Archive February 2013

Antarctic voyage: Mud, mud, glorious mud Guest Work Feb 28

No Comments

Date: 27/2/2013
Location: 66.5914˚S, 148.064901˚E
Weather: 10 knots and clear
Sea state: Calm

3.5khz chirp section. [Helen Bostock]

Antarctic Voyage: The biological pump – the importance of microscopic phytoplankton Guest Work Feb 27

No Comments

Writtenby  Helen Bostock (Marine Geologist, NIWA) and Elizabeth Shadwick (ACE CRC)

Date: 26/2/2013
Location: 65.111248°S, 146.056312°E
Weather: Sunny, less than 20 knots

Simplified Antarctic food web. [Courtney Derriman]

Sea state: 1-3 m swell

Phytoplankton are microscopic plants that live at the surface of the ocean.

There are billions of them in ocean surface waters, which are then grazed upon by millions of zooplankton (including krill), which are eaten by fish, which are eaten by bigger fish, which are eaten by seals and penguins (actually the Adelie penguins eat krill, just like the whales), which are eventually eaten by just a few top predators.

Thus, phytoplankton form the base of the marine food web.

Diatoms under a microscope – Odontella weissflogii, Corethron pennatum, Corethron sp., Asteromphlaus hookeri, Thalssiosira spp. [Leanne Armand, Macquarie University]

Phytoplankton photosynthesise, just like land plants, using sunlight to convert CO2 into organic carbon and oxygen (see blog post 13: The carbon team). The organic carbon is then used by the whole marine food web, and a small fraction of it eventually ends up in the deep ocean. This process of transferring carbon from the atmosphere to the deep ocean is called the biological pump.

As the sea ice melts back each summer in the Mertz Polynya, the surface waters are exposed to sunlight and there is an intense phytoplankton bloom. Due to the upwelling of nutrient-rich deep waters on to the shelf there is no shortage of nutrients (nitrate, phosphate, silicate) to feed this bloom.

The phytoplankton also need minor amounts of iron.  The iron is locally sourced from upwelling waters, dust (although this is minor in this region, it can be a major component in other areas of Antarctica) and coastal sediment.

Some of the resulting biomass then sinks to the sea floor. Thus during the brief Antarctic summer the biological pump is active in this region, transferring atmospheric CO2 to the deep ocean, via the formation of the Antarctic bottom water (see blog post 21: The formation of the Antarctic bottom water).

In the Southern Ocean and around Antarctica, the primary producers are diatoms. As well as organic carbon, these also produce a skeleton made out of silica. These silica skeletons are very intricate and beautiful under a microscope.

The filtering set up – the water is filtered through a 20mm, 5mm, 2mm and 0.45mm filter. [Courtney Derriman]

We have been filtering sea water to collect some of these diatoms (and other phytoplankton). We have also been deploying a plankton net – just like a fine meshed fishing net – to see if we can collect any zooplankton. The different species will be identified under a microscope to determine the abundance and changes in the diversity of the assemblage.

We will also use the filtered and towed plankton samples to test out some new geochemical proxies on the carbonate and silica skeletons. By comparing the geochemical values with modern environmental data (temperature, CO2, nutrients, salinity), we can produce a calibration. We can then analyse the geochemistry of the silica skeletons of the diatoms, which accumulate in the sediment cores, to interpret environmental changes over time (see blog posts 8: The geology team and coring and 22: Could the past be the key to the present).

So while plankton are not quite as photogenic as seals, penguins or whales – at least not with a regular camera as they require a high magnification microscope to view them – these creatures play an central role in the marine food web and global carbon cycle.

Ian Smith (crew) holding up the collection of plankton collected using the plankton net. [Courtney Derriman]

Antarctic Voyage: The discovery of the Mertz Region Guest Work Feb 26

No Comments

Written by Dr Helen Bostock  (Marine Geologist, NIWA).

Date: 25/2/2013
Location: 65.507326°E, 143.982206°S
Weather: Cloudy and foggy, gentle wind (<20 knots)
Sea State: 2-3 m swell

Given the issues we are having with accessing the coast due to the sea ice this year, it seems incredible that just over 100 years ago an Australian expedition landed in this region and spent a couple of years exploring.

In 1910, Australian geologist Douglas Mawson began organising a voyage to explore and chart the essentially-unknown Antarctic coastline directly south of Australia. At the time very little was known about the area between Cape Adare, lying to the south of New Zealand, and Gauss Berg, south of the Indian Ocean.

An American expedition in 1839, under the leadership of Wilkes, had previously reported land. Subsequent exploration, however, showed that most of these landfalls were incorrect and they had probably only encountered the pack ice.

A year later, Dumont D’Urville came within sight of the Antarctic Coast and named the area Adélie Land after his wife.

Mawson was well known, and had proved himself as an explorer during Ernest Shackleton’s 1907-1909 Nimrod Expedition to find the Magnetic South Pole, which was still on land a century ago (see blog post 16: The South Pole).

The Australian Association for the Advancement of Science gave their approval to Mawson’s plans and pledged a significant sum of money towards the cost of the expedition. Large amounts of funding for the expedition was provided by Australian Commonwealth and State Governments, the British Government and the Royal Geographical Society, with the rest made up of donations from the public.

Mawson’s expedition team of 35 individuals was selected primarily from young graduates from Australian and New Zealand universities. It also included a couple of previous acquaintances from his past adventures, including Frank Wild and Frank Hurley, and he recruited Lieutenant Belgrave Edward Sutton Ninnis of the Royal Fusiliers and Dr. Xavier Mertz, an expert Swiss glaciologist, mountaineer and explorer.

The expedition vessel, SY Aurora, was originally built in Dundee, Scotland, and came from the Newfoundland sealing fleet. The Captain of the ship, and second in command, was John King Davis, whom Mawson had known during the Nimrod expedition.

After being refitted in London and sailing to Australia, the Australasian-Antarctic voyage finally left Hobart in December 1911.

They initially stopped at Macquarie Island southeast of Tasmania, and dropped off a team to set up a base. The main scientific objectives were to carry out geographical exploration, biological and geological collections, and undertake meteorological and magnetic observations. As well as land-based field work on Macquarie Island and Antarctica, the expedition also sampled the ocean and seafloor during the voyage.

In early 1912 they first sighted land, which Mawson named Commonwealth Bay. On the far side of the bay was a cape, presumed to be Cape Découverte, the most easterly extension of Adélie Land. Mawson named the adjoining region King George V Land, after the British King.

They established several bases in Antarctica.

Mawson’s hut at Cape Denison, outside – taken during the centenary voyage on the RV Aurora Australis. [Nick Roden, University of Tasmania]

The main base was at Cape Denison in the middle of Commonwealth Bay. After a long winter trapped inside their hut by raging blizzards, several expeditions were sent off to explore in November 1912.

Mawson led a 3 man sledging team to the east with Mertz and Ninnis and a team of Greenland husky sledge dogs. After 3 weeks of excellent progress the party was crossing a large glacier, when Ninnis, 6 dogs, most of the rations, tents and other supplies fell through a snow covered crevasse and were lost. Mawson and Mertz rationalised their gear to just the basics and with 10 days food immediately turned around and started to head back to Cape Denison.

Mawson’s hut at Cape Denison, inside – taken during the centenary voyage on the RV Aurora Australis. [Nick Roden, University of Tasmania]

They supplemented their food supply by eating the 6 remaining dogs. However, after a couple of days Mertz began to deteriorate and died a few days later. It was unknown at the time that huskydogs’ livers contain extremely high levels of vitamin A, which is poisonous to humans.

Mawson continued pulling a sled with geological specimens (a true dedicated scientist) and the last of the food the final 160 km back to the base at Cape Denison. Unfortunately he was too late as SY Aurora had departed just a few hours before he returned. They used the radio to recall the ship, but bad weather prevented any rescue attempt; and Mawson, and six men who had remained behind to look for him, wintered a second year until December 1913.

The large glaciers in the region were named by Mawson after his companions Ninnis and Mertz. Many other geographical features were also named after members of the expedition and the ship. I recommend reading Douglas Mawson’s book “The Home of the Blizzard” to appreciate the conditions they endured on this expedition, and while others were racing to the poles, they dedicated their efforts to scientific exploration.

Mawson is considered the grandfather of Australian Antarctic and Southern Ocean Science, with a large celebration held last year on the centenary of this scientifically successful expedition.

Antarctic Voyage: Hump day – half way through the trip Guest Work Feb 25

No Comments

Written by Dr Helen Bostock  (Marine Geologist, NIWA).

Date: 22/2/2013
Location: 64.838758°S, 142.310661°E
Weather: 20 knots, cloudy
Sea state: 2-3 m swell

Humpback whales

We are now half way through the voyage…. it seems to be going by quickly. While most people were at lunch today, we were visited by 5 or 6 large humpback whales (12-16 m in length): very appropriate for hump day!

The whales ended up swimming and playing around the ship for a couple of hours, putting on a spectacular display for us – breaching, flipper slapping and diving. Several of our photographers got some fantastic images and videos. We will provide these to the whale experts to help them identify the individuals; the experts have named many individuals from their distinct scars and black and white markings on the underside of their tails (also called flukes), and over many years have built up a database of pictures with which they compare whale sightings.

Humpback fluke. [Sue Reynolds]

Humpback breaching. [Sue Reynolds]

Humpback snout. [Sue Reynolds]

Aurora australis

Clear skies over several nights this week have treated those of us on the night shift to views of the aurora australis, or southern lights.

The aurora occurs within 10° to 20° of the magnetic pole (see blog post 16: The South Pole), although during geomagnetic storms it expands into lower latitudes. It is caused by the collision of particles and atoms high up in the atmosphere: the particles originate in the magnetosphere and the solar wind and are then deflected by the Earth’s magnetic field into the atmosphere.

Interestingly, NIWA’s atmospheric research station in Lauder, Central Otago, was originally established in the early 1960s to study the aurora australis.

Aurora australis. [Mark Fenwick]

Antarctic Voyage: Could the past be the key to the present? Guest Work Feb 25

No Comments

Written by Molly Paterson (PhD student, Antarctic Research Centre, VUW).

Location: 65.17903°S, 141.413812°E
Weather: Cloudy with winds up to 30 knots
Sea state: 3-4 m swell

Molly logging a sediment core. [Helen Bostock]

Over the last week, while the oceanographers have been studying the hydrology of the slope, the geologists have recovered two cores.

We hope that by analysing the sediment in the cores for different proxies (see blog post 8: The geology team and coring) we will learn about past changes in the Antarctic bottom water formation and flow over glacial/interglacial cycles (several hundred thousand years).

I am a PhD student from the Antarctic Research Centre, Victoria University in Wellington and interested in much longer time scales. I am studying the evolution of Antarctic Ice volume throughout the Cenozoic (the last 65 million years). My PhD focuses on understanding of the physical mechanisms driving Antarctic ice volume and the downstream influence on bottom water circulation and sea level change.

A central question facing society today is what the potential implications of anthropogenic global warming on Earth’s climate system are. In order to help answer this question, I am examining Earth’s history during periods when atmospheric CO2 concentrations were similar to today, and global mean temperatures were in the range of those predicted by climate models for the end of the century. The Pliocene Epoch (~5.3 to 2.6 million years ago) represents the last time Earth’s climate met these criteria, particularly the warmest interval from 4.3 to 3.0 million years.

Geological drilling by the ANDRILL program (ANtarctic geological DRILLing) documented frequent collapses of the marine-based (i.e. grounded below sea level) Ross Ice Shelf, part of the West Antarctic Ice Sheet throughout the Pliocene.

The Wilkes/Adelie Land region of the East Antarctic Ice Sheet, the region which includes the Mertz Polynya, is also largely grounded below sea level. It has therefore been suggested that this region of the EAIS will be sensitive to similar processes regulating the WAIS. It is thought that the melting of these marine-based ice shelves is dominated by warming of the ocean temperatures – resulting in melting from below – with only minor contributions from the warming of the atmosphere (melting from above).

Part of my PhD focuses on understanding the processes off the Wilkes Land margin by looking at data from sediments in long drill cores that were collected by the Integrated Ocean Drilling Program (IODP) in 2010. We are interested in what the sediments can tell us about changes in the ice sheets and their sensitivity to insolation changes (solar radiation – heating by the sun). The sensitivity of the ice sheets to insolation appears to have changed as the Earth went through a relatively warmer period with higher atmospheric CO2.

So it is great to visit my study area during the voyage and get a feel for what the modern system is like. It has been good to get some hands-on field experience of marine geology – especially coring. I also hope to learn more about the polynya system from the oceanographers on board, as it is central to understanding the stability and changes in the ice shelves.

This voyage is in stark contrast to my previous field work. This time last year I was sleeping in shearer’s quarters, dodging cows and sheep, tramping through rivers, climbing up, down and over Pliocene rocks in order to collect geological samples in the Wanganui Basin, New Zealand.  These rocks provide a record of sea level changes, which were up to 7 m higher during the warmest Pliocene intervals. These sea level changes are directly linked to the ice sheet, and associated volume, changes we see in the cores from the Wilkes Land margin, Antarctica.

Antarctic voyage: The formation of the Antarctic bottom water Guest Work Feb 22

No Comments

Written by Emmanuelle Sultan and Helen Bostock (NIWA)

Date: 20/2/2013
Location: 65.114305°S, 142.304997°E
Weather: Cloudy and calm
Sea state: Calm

One of the primary aims of this voyage has been to monitor the formation of High Salinity Shelf Water at the Wilkes/Adelie Land shelf and its end product, the Antarctic bottom water.

The Antarctic bottom water can be found at the very bottom of the ocean, directly overlaying the sea floor. This cold, salty, and therefore dense water spreads across the very deep, abyssal (greater than 3000 m) plains of the global ocean and can be found as far north as the equator.

This water, which has recently been in contact with the atmosphere, helps ventilate the deep ocean by delivering oxygen to the abyss. It also plays an important role in the carbon cycle with the uptake of carbon via the biological pump (more on this in future blog posts).

Bottom waters are formed in the high latitudes of both hemispheres. In the Northern Hemisphere the densest waters are formed in the North Atlantic Ocean, in the Labrador and Greenland seas. They export the cold water from the arctic ocean into the deep ocean, which travels south via bottom currents through the Atlantic Ocean, eventually mixing with other deep waters in the Southern Ocean.

In the Southern Hemisphere, several different formation spots exist for Antarctic bottom water.

The major sources are the Weddell and Ross Sea, but there are several other source areas around Antarctica. A combination of several factors is required to make a suitable source region: the shape of the coastline, a deep basin acting as a pool or a long thin plateau, and a polynya system (see previous blog post ‘What is a polynya?’).

The Mertz Glacier polynya is a very important location for the production of the dense salty waters. Strong katabatic winds along an L-shaped polynya, over the Adelie Depression, act as a factory for High Salinity Shelf Water during sea ice formation. The High Salinity Shelf Waters pool in the underlying basin, before overflowing and cascading down the Antarctic continental slope, feeding the Antarctic bottom water. It is the third biggest source of Antarctic bottom water after the Weddell and Ross Seas.

Any change to one of the physical parameters may change the rate of Antarctic bottom water production.

The Mertz Glacier Tongue calving that occurred in February 2010 has completely changed the coastline and the ice conditions in this region. The size, shape and location of the polynya has been altered, with a resulting reduction in the High Salinity Shelf Waters that form the Antarctic bottom waters. This will have downstream effects on deep water circulation, the carbon cycle and the climate system.

As the sea ice is currently preventing us from getting on to the Antarctic continental shelf to directly measure the water in the polynya (and retrieve the moorings – see previous blog post ‘What is a polynya?’), we are now focussing our efforts on the continental slope.

We are undertaking a hydrology (water mass) survey using the CTD to look for the outflow of the high salinity, cold, dense waters flowing off the shelf down a series of canyons. We are finding evidence in the CTD profiles for these salty, cold, oxygen-rich waters just above the sea bed. The challenge now is to discriminate between locally formed dense waters from Antarctic bottom water formed in the Ross Sea and then transported west in to this region by the Antarctic Current.

We are still hoping that the sea ice might open up and let us make a dash for the moorings! Keep your fingers crossed for us.

CTD coming up. [Jill Scott]

Analysing the water for nutrients in the lab – Peter Hughes. [Helen Bostock]

CTD in the snow with Ian Smith, on the deck of RV Tangaroa. [Helen Bostock]

Antarctic voyage: What is a polynya? Guest Work Feb 21

1 Comment

Written by Dr Beatriz Pena-Molino (ACE CRC)

Date: 19/2/2013
Location: 65.395795°S, 142.682921°E
Weather: Sunny
Sea State: Calm

But why do we care so much about polynyas?

Sea ice and icebergs. [Adrian Bass]

Antarctic voyage: Q and A Guest Work Feb 20

No Comments

Written by Helen Bostock  (Marine Geologist, NIWA) . Additional answers provided by Courtney Derriman, Jill Scott and Mike Williams

Date: 16/2/2013
Location: 65.184442°S,143.517782°E
Weather: Cloudy, then clearing to a beautiful day
Sea State: calm, 10 knots of wind, very cold!

We have received a number of questions from students at Wellington East Girls’ College and Nelson College for Girls, which we will attempt to answer in this blog post.

Image: Common dolphin. [Adrian Bass]

Typical Day at Sea

The first question we were sent by the students at Wellington East Girls’ College was “what do you do in a typical day at sea?”

Courtney Derriman (MSc Student, Macquarie University, Sydney) endeavours to explain:

My day begins at 11:30pm. That’s right; I am one of the unfortunate souls that got landed with the night shift (12 hours from 12 am to 12 pm).  I swat at my alarm to make it be quiet and then attempt to roll out of my comfy, warm bunk – thankfully I scored the bottom bunk so there is limited risk of injury. It’s then up to the ‘mess’ (dining room) to have my breakfast just before midnight.  It’s shift changeover time, so we catch up with those working during the day to work out where we are in the voyage plan.

I check my emails (my only link to the outside world) and then hopefully there is some work for me to do. Yesterday morning it was a plankton tow, so I got all dressed up in my various layers to go outside. It’s cold and snowing, and it takes about two hours to finish and clean up after the two tows.

And then, smoko time! Not that I smoke, but it is back to the mess for a cup of tea – desperately required to warm up my hands – while others such as Helen are on to their second or third breakfast for the day.

While most of the other people on my shift are involved with the CTD that is currently being deployed, I don’t have that much to do. I read for a while or watch TV until I feel like I should probably be doing something else (the guilt is killer). I update my data sheets, which are in multiple locations: like the majority of the scientists I am paranoid about losing six weeks’ worth of data. While we are on a 12 hour shift, we are not working 12 hours solidly and there is some down time between stations.

6:30am comes and it’s breakfast time (or in our case more like lunch), then back outside again to start filtering some seawater in the hopes of getting diatoms, a type of phytoplankton. The cold waters of the Antarctic are so nutrient rich that diatoms are abundant and the filters quickly begin to clog; I get out my book and wait patiently for gravity and the pump to get the job done. Then I label everything and move on to the next task.

Thankfully, it is now nearly midday and lunch time (or dinner for the night shift). With my twelve hour shift over it’s time for a shower.

Having a shower is not as easy as you think. When it is rough it is very hard to hold on to the rail in the shower and wash without falling over when the ship rolls. While we don’t have to cook and wash the dishes (thanks to Kim and Kris the cooks and Gemma the steward), we do have to make our beds and do our own washing.

I try to unwind by watching a movie or reading a book, and climb in to bed around 3pm, so I can do it all over again tomorrow.  At first trying to get my eight hours sleep at that time of day was impossible, but as week two of our voyage comes to a close, it is beginning to feel normal. Nothing exhaustion and a pair of ear plugs can’t overcome!

Food glorious food….

After mentions of the fantastic food on board, we were not surprised that we got a question about food from the Wellington East Girls College students: “What was it like for the cooks having to plan what food to take for a 6 week trip?”

RV Tangaroa cook Kim. [Jill Scott]

Jill Scott (IT support, NIWA) went to the kitchen to find out more.

The kitchen crew for this voyage consist of two cooks, Kim Ashby and Kris Solly, who work long and hard to ensure that three large meals and numerous snacks are provided for the crew and scientists every day. Being a 24/7 ship means they also leave plenty of food in the fridge for the midnight shift to eat in the early hours of the morning.

The third member of their team is Gemma Charlett, the Steward.  She assists in the mess with continual dishes and cleaning up after meals, as well as general helping, washing and cleaning around the communal areas of the ship.

So, how do the cooks plan and order the food for the six week voyage?

Chief Cook Kim Ashby started cooking on the Tangaroa 10 years ago – with 5 Antarctic voyages already under her belt she is very experienced in cooking and catering for a 6 week voyage.  When she finds out how many people will be going on the voyage, her first step is to work out how much food will be used each day. She needs to allow for any special dietary requests for vegetarians or those on a gluten- or lactose-free diet, and the gender balance as men generally eat a lot more than women. It’s then a quick calculation to multiply everything by the number of days we are at sea for, and voilà, Kim has her shopping list and the food is ordered. During mobilisation the crew spend an afternoon loading up the storage, chiller and freezer….

The day-to-day menus are then planned on a weekly basis during the voyage. With 3 vegetarians and one vegan on this voyage, Kim has tried to ensure there are plenty of salads.

RV Tangaroa’s kitchen. [Jill Scott]

According to Kim, the fresh food will last right till we get back to Wellington. The chiller is filled with boxes and boxes of fresh fruit and vegetables. By the time we are on the homeward stretch we will still be eating carrots, kumara, pumpkins, potatoes and cabbages. The iceberg lettuces have been bagged and amazingly we will still be eating them too. While bits will go ‘yucky’, we eat the good bits.  There are also lots of frozen veggies to supplement the meals.

Are there any challenges in cooking at sea?

Says Kim: While it is lovely on a calm day, rough conditions can make it quite challenging to continue to produce the same high quality meals.  However the kitchen has been modified to keep the pots on the stove and they are always on the alert to watch out for hazards in the rough. For example, there are bars on the stove to stop the pots from moving around in the roughest of conditions, and they use high pans etc.

A day in the life of a cook

RV Tangaroa cook Kris. [Jill Scott]

Kris Solly is enjoying his first Antarctic trip on the RV Tangaroa. As well as assisting Kim in the kitchen, he contributes to keeping up morale on the voyage, collaborating with Gemma to play the odd practical joke on the unsuspecting scientists and crew.

His impression of Antarctica to date is “Cool!”

Kris’s day starts at 5am with preparations for breakfast to be served at 7am. By 8am he has cooked breakfast, made some goodies and fresh bread for morning tea and prepared the vegetables for lunch. Work continues in the kitchen assisting Kim where he can. After serving lunch, he has a bit of a break and returns between 2:30 and 3pm to start preparations for dinner, making salads and cooking vegetables. He manages to fit in two half-hour workouts in the gym each day, while we are eating lunch and then before bed, and in the rest of his spare time he plays a few games.

RV Tangaroa’s chiller. [Jill Scott]

What happens to all the food waste?

According to Gemma, once we are in Antarctic waters (south of 60°S), all food waste is stored in a large, heavy blue box called a dolav (a large bin) that sits out on the deck aft of the kitchen and is returned to Wellington for disposal. Gemma is responsible for emptying the food bin after each meal.  She is on her first voyage to the ice and discovered that it is not quite as easy in the Antarctic conditions.

Gemma has to suit up to go outside, traversing the deck in the cold, windy and sometimes rough and bleak conditions. Even taking the lid off the dolav can be challenging. She will often wait and choose the right moment, waiting for the wind to die down a bit.

Have you noticed any changes now we are in Antarctic waters?

Says Gemma: “Yes. I used to hate going into chiller and freezer. Now they feel quite warm!”

Questions from Nelson College for Girls

1. Isabella: Are the conditions onboard, such as seasickness and cramped conditions, detrimental to the efficiency of the scientists’ mental capacity when conducting experiments?

I don’t think that anyone functions at 100% while they are at sea as all the motion (sea sickness), noise, and lack of sleep make for non-ideal conditions.  Most of the work we are doing is fairly routine, though, so even though we don’t feel our best we can still get our work done.

2. Yulan: What is the hardest part of working (doing science – my words) in Antarctica and why?

The hardest part is probably the funding and logistics.

Once you are in Antarctica, the most difficult problem that makes doing science hard is the cold temperatures. The low temperatures affect the gear, for example icing up mechanical equipment, water freezing in instruments, expanding and potentially breaking them, and batteries generally don’t like the cold.

We also have to make sure we have everything we can possibly need for the voyage as there is no chance to run out to buy stuff along the way that we have forgotten.

3. Unnamed: Do you ever get sick of seeing sea?

Currently the icebergs and sea ice are very cool. But the sea is constantly changing and even when you are a long way out to sea you usually see birds. The sunsets and sunrises can be spectacular.

4. Caitlin: How do you pick where and how far apart you put your devices?

It is a balance between time and the type, and scale, of information that you need to answer your question. So it varies all the time…

On the transit south our stations were roughly 30 nautical miles (55 km) apart – every half a degree of latitude. While on the Antarctic continental shelf, which is shallower (<1000 m), the stations are around 10 km or less apart, as they take less time and the ocean processes are smaller in scale.

5. Shannon: Where does your septic tank empty?

South of 60°S nothing can be thrown overboard. So we just have to store it and take it all back to Wellington. North of 60°S treated greywater can be discharged in to the ocean.

6. Is the boat noisy? Is there a captain constantly driving the ship? Even at night?

Yes the boat is noisy, and because it is so expensive to run a ship we work 24/7 to make the most of the time we have. The captain and 2 officers (or mates) take it in turns to drive the ship, working 4 hour shifts. The scientists and the other crew work 12 hours shifts.

7. Ella: Do weather conditions ever affect your experiments?

Weather plays a large role in our experiments. Currently the sea ice is affecting where we can go in the Mertz Polynya (see the blog post on sea ice, and future blog posts). But in general on research voyages, if the wind gets too strong, and the sea conditions too bad, then it is dangerous to deploy our instruments. Some instruments can only be deployed in really calm weather, while others can be used in reasonably rough conditions.

8. Michelle and Hannah: How do you get chosen to take part in this voyage?

If you are a student, it is studying the right subjects. Then you need to do a postgraduate degree and pick the right supervisor (usually someone who knows someone who knows someone). You also have to be willing to learn and do anything!

Otherwise, for many of us it is part of our job and we go on voyages fairly regularly. Many of the technicians go to sea a couple of times a year and have been to Antarctica many times.

9. Do you have to take the whole supply of freshwater for the trip with you from NZ?

No. We have two distillation plants, which boil and condense water to make freshwater, and one reverse osmosis plant to make fresh water from sea water. Occasionally we get told we need to take short showers and go easy on the water supply as it doesn’t always keep up with demand.

10. Tiana: Does the temperature vary much in Antarctica?

In this region of Antarctica it gets as cold as -30°C in the winter and about 0 in the summer. This morning the air temperature was -8°C, while the ocean is warmer at only -1.5°C. We have had quite a few snow flurries over the last few days, despite its being the middle of summer.

11. Nikita and Clare: Why are the surface waters constantly being checked for CO2 and plankton?

The surface waters vary due to the amount of CO2 in the atmosphere, the temperature of the ocean, the amount of biological productivity, and the windiness (which results in waves).

The oceans buffer the amount of CO2 in the atmosphere, reducing the effects of climate change. But CO2 also reacts with the water and forms carbonic acid, which reduces the pH, a process called ocean acidification. There will be a blog post about this later.

12. Does the condition of the surface water indicate the health of the rest of the ocean?

The surface waters change rapidly, and these changes are transported down into the deep waters (especially in the Southern Ocean). So yes, in some ways the surface waters tell us how the rest of the ocean is going to change.

However, higher pressures, lower temperatures, and slower circulation mean that the deeper waters are quite different and also need to be studied.

13. How expensive is the continuous plankton recorder to build and run?

They are about $40,000 to build, but they are pretty robust and last a long time. The CPR is usually run opportunistically on research voyages, and also on other ships like fishing vessels. So in theory there is minimal cost to actually collecting the plankton as the ships are already going out to sea.

The largest cost is employing the technical experts to analyse the silks and count the plankton, as this is very time consuming.

13. On the map of NZ showing the undersea floor, what are the river- like forms?

These are large canyons – or underwater rivers. They sometimes form just offshore from large onshore rivers. They form when sea level is lower and the rivers continue out to the edge of the continental shelf. Others form because of underwater landslides, while for others we have no idea why they have formed.

They are not all active – some are very old features that formed a long time ago.

14. Is it true that after a long sea voyage you become seasick from the lack of sea motion?

Yes, this is true. I personally struggle more with land sickness when I get off the ship than with sea sickness at the start of a voyage.

When I get back on land the stairs feel like they are moving under me for the first few days, and I have fallen over in the shower my first night back home on solid ground.

And finally, another question from Wellington East Girls’ College students asks “Have you seen much wildlife on the voyage?”

After being escorted out of Wellington Harbour by a pod of dolphins, we have only seen a few sea birds during most of the transit – although there was a rumour that someone spotted a penguin swimming when we were east of Macquarie Island.

Over the last few days, as we have been approaching the Antarctic Shelf, there has been an increase in the abundance of wildlife. The bridge of the RV Tangaroa has been buzzing with scientists and crew with binoculars and cameras at the ready. Minke and humpback whales have been spotted from a long distance, with some curious ones coming up close to the ship (and recorded on the whale record sheets in the bridge). But yesterday when we first encountered the sea ice we got the complete tourist experience.

We have also discovered that we have a talented wildlife photographer on board, Dr Adrian Bass (also masquerading as a chemist). So I will let his photos tell the rest of the story.

Orca. [Adrian Bass]

Bird. [Adrian Bass]

Seal. [Adrian Bass]

Birds. [Adrian Bass]

Antarctic voyage: Sea ice Guest Work Feb 20

No Comments

Written by NIWA oceanographer and voyage leader Dr Mike Williams.

Date: 18/02/2013
Location: 65.225487°S, 143.020138°E
Weather: Small storm clearing
Sea state: 3-4 m swell improving to 1-2 m

Over the last few days the sea ice has given us some of the highs and lows of the voyage.

RV Tangaroa in the sea ice. [Helen Bostock]

Antarctica has showed its treasures as we travel through the ice under a blue sky, with seals and penguins occasionally dotted on the sea ice. The photographers on board have been making the most of this photogenic scenery and charismatic wildlife (see our upcoming Q&A blog post).

We are here at the end of summer and our hope was that the ice would be at its minimum extent, with open passages (or leads) for us to get through to the coast.  In winter this isn’t an option as the sea ice is at its maximum extent. At that time, it nearly doubles the size of Antarctica – the largest annual change of any natural system on the planet.

Sea ice forms from freezing sea water. Once thick enough, it insulates the ocean from the atmosphere. This limits the ocean to a chilling temperature of -1.9°C (it’s colder than fresh water because of the salt in the ocean), while the atmosphere above cools to -40°C or colder during winter.

Pancake ice. [Helen Bostock]

The first ice to form is frazil ice. These are individual crystals of ice that are only microns in size, but they grow rapidly and form into small discs, called pancake ice. The pancakes grow by waves splashing over them, and more water freezing onto the bottom.  Eventually these grow together dampening out the waves that would break them apart. Once glued together the ice thickens to as much as 2 m for first-year ice near the coast, and around 0.5 -1 m out at the edge of the pack ice.

In winter the loose floes of the marginal ice zone (MIZ ) lie further north. Here the ice is unable to form a solid sheet, as the swell rolling in from the Southern Ocean bends and breaks the floes. As summer comes the ice starts to melt, mainly from underneath as the water warms faster than the air in the sun. The MIZ moves south, allowing the swell and the warming water to break and melt the rest of the pack ice.

By the end of summer the MIZ has retreated significantly. Much of what is left is multi-year ice. Some is first-year ice, but if that lasts another month of summer it will become multi-year ice as well.

The multi-year ice is thicker and more convoluted in shape, the result of wind, which pushes one floe over the top of another. This is then covered with snow, leaving the multi-year ice up to several metres thick.

It’s the MIZ we had hoped to sail through to get in to the Mertz Polynya (see upcoming blog posts). On Saturday night, however, the captain announced that the ice was too bad. We won’t be going any further south unless the situation changes significantly. This was the low the sea ice delivered. We are unlikely to be working on the continental shelf this year. The ice has put plans A and B (see blog post 2) out the window.

So we have moved to Plan C. This will focus on the continental slope looking for the outflow of heavy dense water which overflows from the continental shelf down the canyons (see future blog posts).

The first discussion about Plan C was at 4 am. Now, in daylight a couple of days later, and with more satellite images of the current sea ice situation, we can see it is the best decision, particularly as we struggle to slowly move north at 1 knot, the ship shuddering as we push aside the ice floes.

Also in amongst the first year and multi-year ice there are patches of pancake ice starting to form. We don’t want to get trapped. Better to be safe than sorry.

Antarctic voyage: Sailing through thin ice Guest Work Feb 19

Written by Helen Bostock (marine geologist, NIWA)

Date: 17/02/2013
Location: 65.627268°S, 144.277825°E
Weather: Cloudy, calm and very cold
Sea State: Calm

Over the last few days we have seen a lot of icebergs and have been skirting along the edge of the sea ice.

‘Patience….’ is the main advice of our Danish ice pilot, Arne Sorensen, when sailing the ship through areas with sea ice.

‘Slow and steady. The force of the impact if we hit the ice is related to the square of the speed that the ship is travelling at. So the faster you go, the more likely you will damage the ship.’

sea ice

Sea ice [Adrian Bass]

The RV Tangaroawas built in Bergen, Norway, in 1991. She is not an ice breaker. But she has an ice strengthened hull, and is an ice 1C class ship. This means that she can push her way through light ice floes of up to 0.4 m thick.Arne has been to Antarctica 20 times and the Arctic over a dozen times on a wide range of ships, with different missions. He has spent the last few years working specifically as an ice pilot, advising and training ship’s officers to negotiate icy conditions.Arne started going to sea when he was 16 years old as a cadet for a Danish shipping company. His father had been a sailor and then worked in the lighthouse, and his older brother was already working on ships. As a cadet he had to work on the deck, as well as learning how to be an officer. In Denmark they have compulsory national service: naturally, Arne spent his with the navy. After that he continued working on supply ships as a mate and then a Captain, and spent a couple of years working in eastern Greenland. Then he started coming down to Antarctica.

He says there are some differences between the sea ice in the Arctic and Antarctic. There is more multiyear ice in the Arctic (sea ice that hasn’t melted during the summer). First year ice has more salt in it and is “spongier”, while multiyear ice is harder and thicker.

Sea ice

Sea ice [Adrian Bass]

 In the Antarctic there are a lot more large icebergs, some of which get grounded on the shallow banks on the continental shelf. The icebergs affect the distribution of the sea ice. The east of an ice tongue, or ice berg, is usually iced up with “fast ice” (unlikely to break up and melt). This is due to the direction of the winds which transport ice from east to west. But you can’t assume that it will be the same every year, and the conditions can change very quickly.Arne is now retired. He chose to come on this voyage as he is interested in the science and still enjoys the challenge of navigating through the ice. “It is a balance between being cautious and trying to get the job done.”Evan Solly, the master, has been down to Antarctica 8 times, 7 times on the RV Tangaroa, while first mate Ian Popenhagen has been 6 times. So between them and the ice pilot they have 35 years of experience working in these icy conditions. Second mate Daniel Hayward, who is on his first trip to Antarctica, will benefit with expert training from them all.

Many of the crew have also been down to Antarctica before. Mike Steele, the bosun for the last 36 years, has been down many times. He is thankful for the improved clothing that they now have to cope with the extreme conditions, though he still isn’t completely satisfied with the gloves… Despite this, I feel we are in good hands.

Network-wide options by YD - Freelance Wordpress Developer


History Teacher: Educational Requirements

Learn about the education and preparation needed to become a history teacher. Get a quick view of the requirements as well as details about training, job duties and certifications to find out if this is the career for you.

Essential Information

History teachers provide students with a broad exposure to historical events and processes as well as access to various threads of thought from antiquity through the present day. They often gain employment in junior high school, high school and college. History teachers plan lessons, grade assignments, assess student progress and ensure that students meet learning yearly learning objectives. Becoming a history teacher at the middle or high school level generally entails completion of a bachelor's degree program in history with a teacher education component. History teachers at the college level typically hold a doctoral degree.

Junior High School High School Postsecondary
Required Education Bachelor's degree Bachelor's degree Master's or doctoral degree
Other Requirements Teacher certification program and state licensure Teacher certification program and state licensure None
Projected Job Growth (2012-2022)* 12% 6% 14%
Median Salary (2014)* $54,940 annually $56,310 annually $66,840 annually

Source: *U.S. Bureau of Labor Statistics

Career Options

History teachers often teach at the junior high, high school or postsecondary levels. Read more about each of these teaching levels in the sections below.

Junior High School Teacher

Junior high or middle school history teachers instruct different groups of students from grades 6 through 8. The courses are usually specialized, focusing on topics in world history, American history and civics. A bachelor's degree is required to teach history at this educational level, in addition to the successful completion of a teacher education program. State education boards also require junior high and middle school history teachers to receive a teaching license, which includes passing a subject-specific certification exam.

According to the U.S. Bureau of Labor Statistics (BLS), jobs for junior high school history teachers are expected to increase by 12% from 2012 to 2022, which is on par with the national average for all jobs. The BLS also reports that junior high history teachers earned a median annual salary of $54,940 as of May 2014.

High School History Teacher

High school history teachers can instruct students on various cultures and time periods, such as the Renaissance and the Enlightenment, or they can focus on particular areas, like American or European History. History teachers at this level also offer courses in related areas like economics or sociology. Individuals wanting to become a high school history teacher are required to earn a Bachelor's degree and complete a teacher education program. They must also demonstrate mastery of their subject area by passing a state-approved examination.

The job growth percentage rate for high school history teachers is estimated to be slower than the national average, with only a 6% increase from 2012 to 2022 ( The BLS further reports that high school history teachers earned a median yearly salary of $56,310 as of May 2014.

Postsecondary History Teacher

Postsecondary history teachers instruct students in large and small colleges and university and online. They often provide specialized instruction on various subtopics within the field such as American history and modern European history. While there is no formal teacher education program necessary for postsecondary history teachers, individuals are required to have at least a master's degree in history for part-time and adjunct teaching positions. A doctoral degree is necessary for a tenure-track, university position. In addition to preparing lessons, giving assignments and grading student work, postsecondary history teachers conduct their own research and write articles for scholarly publications.

Jobs for postsecondary history teachers are expected to grow at a rate of 14% from 2012 to 2022, according to BLS. This is due to the continuing rise of student enrollment at this level. As of 2014, the median salary for postsecondary history teachers was $66,840 per year.

Educational Requirements for History Teachers

Bachelor's Degree in History Education

While history teachers who do not hold degrees occasionally find employment in private schools, history teachers in public schools are required to hold four-year degrees that combine history and teacher education. Aspiring teachers may benefit from attending programs accredited by the National Council for Accreditation of Teacher Education or the Teacher Education Accreditation Council.

History Curriculum

History teacher education programs cover various cultures and time periods, such as the Renaissance and the Enlightenment. Some programs offer students the opportunity to specialize in a particular area of interest, like American history. Additionally, programs may require students to complete a writing requirement, such as one or more papers on a historical time period or development.

Teacher Education Curriculum

Aside from courses in history, students must complete coursework to prepare them for classroom instruction. These courses typically fulfill state teacher credentialing requirements and may cover topics in curriculum development and teaching methods. Some states also require teacher education programs to include technology training that familiarizes aspiring teachers with the use of computers in classroom instruction.

Most teacher education programs also require aspiring teachers to complete student-teacher internships. These opportunities allow prospective history teachers to design curricula and experiment with instructional techniques under the supervision of licensed instructors.

Alternative Programs

In order to compensate for understaffing in some subjects, state governments have developed alternative programs to help college graduates gain the necessary skills to teach in public schools. For example, some states allow graduates of history degree programs to teach while taking evening classes to fulfill educational requirements. Others allow aspiring teachers to enroll in full-time, one to two semester programs that consist of the necessary teacher education coursework.

Related to History Teacher: Educational Requirements

Search Degrees, Careers, or Schools


Radio immuno assay

Presentation Description

No description available.

Presentation Transcript

Radioimmunoassay By- Nidhi Lathia M.pharm (Sem -I) Pharmaceutics Atmiya Institute of Pharmacy Rajkot.

Slide 2:

Immunoassay: Antibodies, Antigens and Analytes Defined An antibody is a protein that is produced by the body in response to an “invading” (foreign) substance.* Antibodies are produced as part of the body’s immune response to protect itself. For instance, some immunoassays test for the presence of antibodies to cancer molecules. Thus, if the antibodies are present, it means invading cancer cells are, too. An antigen is the substance that the body is trying to “fight off” (eliminate or reduce) by mounting an immune response. Some immunoassays test for antigens directly, rather than looking for the antibodies. In a test to measure the concentration of a therapeutic drug, for example, the drug is the antigen that binds to the antibody. 2 Radioimmunoassay

Slide 3:

Immunogen : An Immunogen is a substance that elicits immune response i.e. drug-protein conjugate. Analyte: An analyte is anything measured by a laboratory test. In immunoassay testing, the analyte may be either an antibody, or an antigen. * AN EXCEPTION IS THE CASE OF AUTOIMMUNE DISEASES , WHERE THE BODY PRODUCES ANTIBODIES TO NATURALLY OCCURRING PROTEINS RATHER THAN FOREIGN SUBSTANCES. 3 Radioimmunoassay

What is ‘LABEL’?:

What is ‘LABEL’ ? All immunoassays require the use of labeled material in order to measure the amount of antigen or antibody present. A label is a molecule that will react as a part of the assay, so change in signal can be measured in the solution. The label can be applied during the manufacture of the reagent to either Ab or Ag. Example of label includes- A radioactive compound An enzyme that causes a change of colour in solution A substance that produces a light 4 Radioimmunoassay

Slide 5:

Radioimmunoassay: An assay based on the reversible and non- covalent binding of an antigen (hapten) by a specific antibody employing radioactivity labelled antigen (hapten) to measure the fraction of the antigen (hapten) bound to a substoichiometric amount of antibody. The technique of radioimmunoassay has revolutionized research and clinical practice in many areas, e.g., blood banking diagnosis of allergies endocrinology Dr. Rosalyn Yalow became the first female to win a Nobel Prize with her work on the radioimmunoassay. 5 Radioimmunoassay

History and Background:

History and Background 1972 First Hepatitis RIA 1972 EMIT Assay 1975 Bead-based Assays 1978 Coated-tube assays 1985 HIV Immunoassay 1993 TroponinAssays 1997 Automated Cytokine Assays (Evans) 6 Radioimmunoassay

Immunoassays at a Glance:

Immunoassays at a Glance Immunoassays are a group of sensitive analytical tests that utilize very specific antibody/antigen complexes to produce a signal that can be measured and related to the concentration of a compound in solution . Immunoassays also produce qualitative data in terms of the presence (+) or absence (-) of a compound in the body. They are used in a lot of laboratories, including hospitals labs, and have been widely used in the special area of Forensic Toxicology to screen for drugs and other chemicals in the body. 7 Radioimmunoassay

Principle It is based on the competition between unlabelled antigen & a fixed amount of the corresponding radio labelled antigen for limited number of antibody binding sites in fixed anount of antiserum. At equilibrium, the unbound antigen (F)+ Antigen-antibody complex(Ag-Ab) are separated & quantified. Ag(larger) + Ab Ag-Ab Ag*(smaller) + Ab Ag*-Ab In std. Condition, amount of labeled antigen bound to the antibody decreases as the amount of unlabelled antigen increases in sample. The reaction between Ab and Ag* is quantified by counting either the bound (B) or the free labeled compound (F). 8 Radioimmunoassay

Principle The amount of labeled compound bound to antibody is dependent on The amount of ligand (Ag +Ag *) present The amount of antibody ( Ab ) present The equilibrium constant/ affinity constants k1’ and k2’ where, k1’ = k1/k2 and k2’=k3/k4. k1 Ag* + Ab k1 Ag*-ab and , k2 Ag + Ab k1 Ag-Ab k2 In assay Ag* and Ab are constant as binding of Ag* solely depends on amount of Ag present. % F = [F/ (F+B)]*100. % B = [B/ (F+B)]*100 9 Radioimmunoassay

Principle :

Principle Fig 3.7.1 RIA before and after Incubation - Blank and Three Standard Samples A Blank and Three Standard Samples 10 Radioimmunoassay

Production of Antibodies:

Production of Antibodies The production of antibodies is an important process in the use of immunoassays because it is the antibody-antigen complexes that form that the device uses for its results. Antibodies can be called monoclonal or polyclonal, depending upon the technique used to produce it. Monoclonal antibodies involve these basic steps and result in very specific antibodies that bind only to one antigen epitope , which in turn reduces the occurrence of false positives in the immunoassay: A mouse (or rabbit) is immunized by being injected with an antigen; the antigen generates an antibody response in the animal. The mouse is sacrificed and the antibody forming cells are isolated from the mouse's spleen. Monoclonal antibodies are produced by fusing single antibody-forming cells with myeloma cells. The resulting cell is called a hybridoma . This hybridization makes the cells “immortal.” The hybridomas contain large amounts of antibodies, and can easily be cultured into populations of cells that contain identical antibodies. These antibodies are called " monoclonal antibodies " because they are produced by the identical offspring of a single, cloned antibody producing cell. (UCLA) 11 Radioimmunoassay

Production of Antibodies Cont’d:

Production of Antibodies Cont’d A diagram depicting the steps involved in monoclonal antibody production. 12 Radioimmunoassay

Production of Antibodies Cont’d:

Production of Antibodies Cont’d Polyconal antibodies are more likely to produce a false positive because they are less specific to antigen epitopes and have varying binding affinities; they may bind of molecules similar to their antigens. Production includes these steps: A mouse (or rabbit) is immunized by being injected with an antigen; the antigen generates an antibody response in the animal. The animal is bled and the antibodies are collected; the blood contains a heterogenous mixture of antibodies of varying binding affinities and specificities. 13 Radioimmunoassay

Slide 14:

Radioimmunoassay 14 Multiple antigen specificities of polyclonal antibodies Uniform specificities of monoclonal antibodies

Slide 15:

Labeled antibodies allow detection of antigen/antibody complexes in immunoassays Labeled antigen also allows detection of antigen/antibody complexes in immunoassays 15 Radioimmunoassay

Slide 16:

Classification of immunoassays: Competitive & Non-competitive immunoassays. 2.Homogeneous & Heterogeneous immunoassays. 3.Limited reagent assays & Excess reagent assays. 16 Radioimmunoassay

Slide 17:

Competitive format In competitive formats, unlabelled analyte (usually antigen) in the test sample is measured by its ability to compete with labeled antigen in the immunoassay. The unlabeled antigen blocks the ability of the labeled antigen to bind because that binding site on the antibody is already occupied. Thus, in a competitive immunoassay, less label measured in the assay means more of the unlabeled (test sample) antigen is present. The amount of antigen in the test sample is inversely related to the amount of label measured in the competitive format . Amount of antigen is indirectly related to the amount of label (signal) in competitive formats Radioimmunoassay 17

Slide 18:

One step competitive immunoassay Two step competitive immunoassay 18 Radioimmunoassay

Slide 19:

Noncompetitive (Sandwich) Method Noncompetitive assay formats generally provide the highest level of assay sensitivity and specificity and are applied to the measurement of critical analytes such as cardiac and hepatitis markers. This format is referred to as a “sandwich” assay because analyte is bound (sandwiched) between two highly specific antibody reagents Noncompetitive sandwich method of immunoassay 19 Radioimmunoassay

Slide 20:

Figure -11 Amount of antigen is directly related to the amount of label (signal) in competitive formats 20 Radioimmunoassay

Slide 21:

Homogeneous and Heterogeneous Immunoassay Methods Immunoassay methods that require separation of bound Ab- Ag* complex are referred to as heterogeneous immunoassays. Those that do not require separation are referred to as homogeneous immunoassays . Homogeneous methods have been generally applied to the measurement of small analytes such as abused and therapeutic drugs. Since bound complex releases a differentiated signal from the unbound reactants, homogeneous methods do not require the separation of the bound Ab-Ag* from the free Ag* and thus they are generally much easier and faster to perform. 21 Radioimmunoassay

Slide 22:

Figure -12 Homogeneous and heterogeneous immunoassays 22 Radioimmunoassay

Slide 23:

Limited reagent assay: Many conventional RIAs follow limited reagent assay protocols. The following scheme depicts the AgAb reaction: Ag AgAb + Ab Ag* Ag*Ab With limited amount of Ab, the unlabeled antigen (analyte) competes with the labeled antigen Ag* for limited binding sites. Bound fraction [AgAb] is separated from free [Ab], and the signal [Ag*Ab] complex i.e. the Ab fraction not occupied by the analyte is measured. The amount of analyte is inversely proportional to the bound [Ag*Ab] complex in a hyperbolic function. 23 Radioimmunoassay

Slide 24:

Excess-Reagent assay This protocol is utilized by- 1. Immunoradiometric Assays (IRMA). 2. Two-site or sandwich Assays . Here the excess Ab is labeled.(In case of sandwich assay an excess amount of first Ab used to capture analyte from sample matrix, and a labeled second Ab provides the signal for quantitation .) IRMA : Ag + Ab* AgAb * Sandwich assay: Ag + Ab1 Ag-Ab1 + Ab2* Ab1-Ag-Ab2 * Bound fraction is separated from free; the signal [AgAb*] or [Ag-Ab1-Ab2*] complex is measured . The amount of analyte is proportional to the bound complex in a hyperbolic function. 24 Radioimmunoassay

The Technique :

The Technique A mixture is prepared of radioactive antigen Because of the ease with which iodine atoms can be introduced into tyrosine residues in a protein, the radioactive isotopes 125 I or 131 I are often used. antibodies against that antigen. Known amounts of unlabeled ("cold") antigen are added to samples of the mixture. These compete for the binding sites of the antibodies. 25 Radioimmunoassay

Slide 26:

At increasing concentrations of unlabeled antigen, an increasing amount of radioactive antigen is displaced from the antibody molecules. The antibody-bound antigen is separated from the free antigen in the supernatant fluid, and the radioactivity of each is measured. 26 Radioimmunoassay

Slide 27:

27 Radioimmunoassay

Reagents used in RIA:

Reagents used in RIA A tracer i.e. a labelled ligand. A binder (Antibody) which is the specific antiserum. A separation system to separate the ‘bound’ and ‘free’ phase. A standard i.e. the ligand (analyte) in highly pure form. A ligand (analyte) - free human antiserum. 28 Radioimmunoassay

Tracers The radioisotopes used are – Beta (positron) emitters- 3 H , 14 C, 11 C, 13 N, 15 O, 18 F Gamma emitters- 125 I, 111 In, 123 I, 131 I, 75 Se Positron vs. Gamma Isotopes: Positron emitters are more appropriate for the direct labeling of drug molecules since the γ-emitting radionuclides are rarely an integral part of the drug molecule structure. The positron (β-emitting) radionuclides are mainly restricted for invitro experiments. The γ-emitting radionuclides are useful for in-vivo imaging. 29 Radioimmunoassay

Radiolabelling Techniques:

Radiolabelling Techniques Isotope Exchange Reactions Introduction of a Foreign Label Labeling with Bifunctional Chelating Agents Biosynthesis 30 Radioimmunoassay

Specific antiserum (Binder, Ab):

Specific antiserum (Binder, Ab ) It is prepared by injecting (repeatedly) the antigen together with the Freund’s adjuvant into a suitable animal such as guinea pig, rabbit or goat. Freund’s adjuvant: It is a mixture of neutral detergent , paraffin oil and killed mycobacterium. It increases the antibody response of the injected antigen Molecules like thyroid hormones, steroids, drugs are not immunogenic. So they are conjugated to carrier proteins and polymers to make them immunogenic. Carrier Molecules: Bovine Serum Albumin (BSA). Egg Albumin. Gamma globulin. Haemocyanin. Fibrinogen. Thyroglobulin. Synthetic Polypeptides. E.g. Poly Lysine, Poly Glutamic acid. Synthetic polymers. E.g. PVP. 31 Radioimmunoassay

Specific antiserum (Binder, Ab):

Specific antiserum (Binder, Ab ) Active group of Protrin carriers for conjugation to heptanes: Amino group of Lysine. –SH group of Cysteine. Imidazole ring of Histidine. –COOH group of Aspartic and Glutamic acid. Phenolic group of Tyrosine. –OH group of Serine. Terminal -NH 2 and –COOH groups. Active positions on rings of Tyrosine, Tryptophan and Histidine can be attached to diazepam salt. 32 Radioimmunoassay

Specific antiserum (Binder, Ab):

Specific antiserum (Binder, Ab ) After 2-3 weeks of immunization, serum of the animal is collected, tested for antibody and suitably diluted before storage. Good quality antiserum is obtained after 3 – 4 booster doses. Antibodies produced are polyclonal i.e. mixture of antibodies specific to different epitopes on the antigen. They have different specificity and avidity and it may vary from animal to animal and batch to batch quality. Monoclonal antibodies are produced by ‘Hybridoma Technique’ propagated from a single cell, uniform in their binding characteristics within batch and also from batch to batch. 33 Radioimmunoassay

Characterization of Antiserum:

Characterization of Antiserum Titre – It is the degree to which the antiserum can be diluted so that it is usable in the assay. The dilution of the antiserum that corresponds to 30% - 50% of binding is taken as the titre of that antiserum. It depends upon – The amount of tracer used, The incubation volume and temperature The % binding with the tracer adopted in the optimized assay. Avidity – It is the energy of binding to the specific antigen. It is expressed in terms of equilibrium constant K. Higher the ‘ avidity ’ greater the sensitivity of RIA. 34 Radioimmunoassay

Characterization of Antiserum:

Characterization of Antiserum 3. Sensitivity – It is the lowest of ligand which can be distinguished from the absence of ligand in that assay. 35 Radioimmunoassay

Characterization of Antiserum:

Characterization of Antiserum 4. Specificity – It is the ability of the antibody to react with specific antigen and no other antigen. It is not always absolute, and may react with chemically resembling analyte. 36 Radioimmunoassay

Separation system:

Separation system RIA requires a separation procedure because the bound fraction does not precipitate spontaneously at the low concentration employed. Variety of procedures are available that exploit physicochemical or immunological differences between the two fractions. They are: Physical methods include: filtration, chromatography, electrophoresis, charcoal- dextran adsorption, adsorption on ion-exchange resin. Chemical methods include: organic solvents, such as ethanol, dioxane and PEG, or salts, such as sodium, zinc and ammonium sulphate, to precipitate antibody bound heptan. Solid phase system. No one is ideal in establishing a new assay as two or more principles employed for separation. 37 Radioimmunoassay

Separation system:

Separation system Basis of method Material/technique used 1. Differential migration of the bound & free fraction by- (a) Differences in charge. Paper chromatography Electrophoresis. (b) Differences in relative molecular mass Gel filtration , Gel equilibration. 2. Adsorption of the free fraction Coated charcoal Ion exchange Resin 3. Precipitation of the bound fraction by- (a) Organic solvent Ethanol, Dioxane , PEGs (b) Salt Sodium or Ammonium sulphate (c) Second antibody 4. Solid phase Methods Coated on tubes or discs (a) First antibody Covalently linked to sephadex paper discs (b) Second antibody Covalently linked to solid matrix. Techniques employed for the separation of bound and free antigen . 38 Radioimmunoassay

Standard A standard i.e. the ligand (analyte) in highly pure form: Drugs, proteins, Hormones etc. must be in pure form, so they can be diluted and aliquoted in precisely measured quantities. Standards are prepared in ligand free serum. In case of protein hormones, the standard should be prepared preferably with the hormone from the species from which the serum is going to be analyzed. 39 Radioimmunoassay

Ligand free human serum:

Ligand free human serum It is prepared by treating human serum with charcoal that absorbs the smaller antigens. It can also be prepared by collecting serum from volunteers in whom production of that ligand or hormone has been inhibited by treatment with an appropriate drug. 40 Radioimmunoassay

Assumptions for RIA validity:

Assumptions for RIA validity The standard is structurally identical with the analyte. However, the labelled antigen (Ag*) need not be structurally identical with the analyte , provided that it closely mimics their behaviour of the analyte with the antibody. The equilibrium constant K between the antibody (Ab) and antigen (Ag) and that between labelled antigen (Ag*) and antibody (Ab) is of the same order of magnitude. The separation of bound and free phases is perfect which is not always the same case. One molecule of antibody (Ab) binds to only one molecule of antigen (Ag) or labelled antigen (Ag). All the reactions between the antibody (Ab) and antigen (Ag) and that between labelled antigen (Ag*) and antibody (Ab) are taken to equilibrium, although many assays are done under non-equilibrium conditions. 41 Radioimmunoassay

Advantages & Disadvantages of RIA:

Advantages & Disadvantages of RIA Advantages:- Highly specific: Immune reactions are specific High sensitivity : Immune reactions are sensitive Indirect method of analysis Saturation analysis Disadvantages:- Radiation hazards: Uses radiolabelled reagents Requires specially trained persons Labs require special license to handle radioactive material Costly Requires special arrangements for Requisition, storage of radioactive material radioactive waste disposal. 42 Radioimmunoassay

Applications Narcotics (drug) detection, Blood bank screening for the hepatitis (a highly contagious condition) virus, Early cancer detection, Measurement of growth hormone levels, Tracking of the leukemia virus, Diagnosis and treatment of peptic ulcers, and Research with brain chemicals called neurotransmitters Endocrinology Insulin, HCG, Vasopressin Detects Endocrine Disorders Physiology of Endocrine Function Pharmacology Morphine Detect Drug Abuse or Drug Poisoning Study Drug Kinetics Epidemiology Hepatitis B Clinical Immunology Antibodies for Inhalant Allergens Allergy Diagnosis Oncology Carcinoembryonic Antigen Early Cancer Detection and Diagnosis 43 Radioimmunoassay

RIA for Insulin:

RIA for Insulin Reagents used :- Each kit is sufficient to run 250 tubes and contain following reagents: Asaay buffer: 0.05M Phosphosaline buffer, pH 7.4, containing 0.025m EDTA, 0.08% Sodium azide & 1% RIA grade BSA. Antiserum: Guinea pig anti rat insulin serum in assay buffer. 125 I -Insulin: 125 I –Insulin label , HPLC purified. Label Hydrating Buffer: Assay buffer containing normal guinea pig IgG as carrier. Standards: Purifies rat Insulin standard buffer at different concentration. Quality controls 1 & 2: Purified rat Insulin in assay buffer. Precipitating reagent: Goat anti-guinea pig IgG serum, 3% PEG & 0.05% triton X-100 in 0.05M Phosphosaline, 0.025M EDTA , 0.08% sodium azide. Radioimmunoassay 44

Specimen collection & storage:

Specimen collection & storage Radioimmunoassay 45

Assay procedure [Day 1]:

Assay procedure [Day 1] Radioimmunoassay 46

Assay procedure [Day 2]:

Assay procedure [Day 2] Radioimmunoassay 47

Assay procedure [Day 2]:

Assay procedure [Day 2] Radioimmunoassay 48

GUIDELINES TO SET UP A RIA LABORATORY Radioimmunoassay 49 Handling facility and Staff requirement for starting RIA laboratory

GUIDELINES TO SET UP A RIA LABORATORY Radioimmunoassay 50 Other facilities required :-

Slide 51:

Radioimmunoassay 51

Enzyme Immunoassay:

Enzyme Immunoassay In EIAs, enzyme labels are used in place of radioactive labels. Typical enzyme labels are alkaline phosphatase, horseradish peroxidase, B-galactosidase, glucose oxidase, p-nitrophenyl phthalate and o-nitro phenyl phthalate galactosidase. Whereas RIAs use radioactivity to measure the concentration of analyte, EIAs typically use a change in color, emission of light, or other signal. Specific equipment is required to quantitate the amount of enzyme present by measuring the specific change that occurred. Radioimmunoassay 52

Enzyme Immunoassay:

Enzyme Immunoassay The two types of Enzyme immunoassay are- Enzyme mediated (multiplied) Immunoassay tevhnique(EMIT) Enzyme linked immunosorbent assay (ELISA). Enzyme immunoassay 53

EMIT Enzyme mediated (multiplied) Immunoassay technique It has been widely used for rapidly assaying micro amount of drug and substance in biological fluid. Key elements are- Compound to be measured (heptan). Enzyme labelled molecules of compound. Specific antibody that binds the compound. Enzyme chromogenic substrate i.e. initially colourless but gives colour with enzyme It is homogeneous method of analysis means there is no need to wash excess of enzyme labelled antigen. Method does not involve solid phase system but enzymes are active in free form but inactive in bound form. Enzyme immunoassay 54

EMIT Two basic test principles are involved in EMIT- The enzyme must retain enzymatic activity even after the heptan or antigen conjugation takes place. 55 Enzyme immunoassay

EMIT 2. The enzyme activity of the heptan-enzyme conjugate is reduced or inhibited when the heptan reacts with specific antibody. EMIT drug assay begins by adding to a patient specimen, an excess of specific antibodies that will bind to the drug being measured. If drug molecules are present, they immediately bind to antibody sites. The enzyme labelled drug is then added to the mixture. 56 Enzyme immunoassay

EMIT Antibody binding sites not occupied by molecules of the drug in the specimen and are immediately filled with molecules of added enzyme labelled drug. Enzyme activity is then reduced because only free enzyme-labelled drug conjugate can act on the substrate. The amount of substrate converted from a colourless to a coloured product in a given period of time is determined by the amount of free enzyme left in the mixture. 57 Enzyme immunoassay

EMIT This result in colour change i.e. measured by spectrophotometrically. The specimen drug concentration is measured by comparing the absorbances of test and standard. The absorbance obtained is directly proportional to the drug concentration in sample. As it is homogeneous assay there is no need for separation of bound from unbound compound as it is necessary with other Immunoassay like ELISA. Sensitivity of EMIT can be increased by using enzyme reaction followed by fluorescent substrate but there may be a problem of quenching. Application: Rapid detection of virus, hormones, drugs, insecticides etc. 58 Enzyme immunoassay

ELISA A 96-well microtiter plate being used for ELISA 59 Enzyme immunoassay

Equipments 60 Enzyme immunoassay

Slide 61:

61 Enzyme immunoassay

ELISA Kit 62 Enzyme immunoassay

ELISA Enzyme-linked immunosorbent assay, also called ELISA, enzyme immunoassay or EIA, is a biochemical technique used mainly in immunology to detect the presence of an antibody or an antigen in a sample. The ELISA has been used as a diagnostic tool in medicine and plant pathology , as well as a quality control check in various industries. 63 Enzyme immunoassay

Types of ELISA:

Types of ELISA Indirect ELISA Sandwich ELISA Competitive ELISA Reverse ELISA 64 Enzyme immunoassay

Slide 65:

Variations in the enzyme-linked immunosorbent assay (ELISA) technique, similar to RIA except using an Enzyme (alkaline ⓟ, horseradish peroxidase, & β-galactosidase) : safer & less costly. to detect Ab (HIV, HCV) to detect Ag to detect Ag 65 Enzyme immunoassay

Application Detecting infections Sexually transmitted agents like HIV, syphilis & Chlamydia Hepatitis B and C Toxoplasma gondii Detecting allergens in food and house dust Measuring ‘rheumatoid factors’ and other autoantibody in autoimmune disease like Lupus erythematosus. Measuring toxins in contaminated food. 66 Enzyme immunoassay

Application Screening donated blood for evidence of viral contamination by:- HIV-1 & HIV-2 (presence of anti-HIV antibodies). Hepatitis C (presence of antibodies) Hepatitis B (testing for both antibodies & a viral antigen) Measuring hormone levels HCG (as a test for pregnancy) LH (determining the time of ovulation) TSH, 3 AND T4 (for thyroid function) 67 Enzyme immunoassay

Application ELISA is used to detect many bacterial and viral antigens including HIV, malaria, cholera, measles and mumps. The ELISA has been used as a diagnostic tool in medicine and plant pathology, as well as a quality control check in various industries. 68 Enzyme immunoassay

ELISA for Insulin :

ELISA for Insulin 69 Enzyme immunoassay

ELISA for Insulin :

ELISA for Insulin 70 Enzyme immunoassay

Fluorescence immunoassay:

Fluorescence immunoassay

Slide 72:

72 Enzyme immunoassay

authorStream Live Help


To Name :
To Email :
From Name :
From Email :
Comments :

Evidence-Based Reviews

Transcend dread: 8 ways to transform your care of ‘difficult’ patients

An empathic, relaxed approach can ease frustration and improve the therapeutic alliance

Vol. 8, No. 9 / September 2009

Comment on this article

In a psychiatric clinic, Dr. B treats Ms. D, a single 28-year-old, for depression. She has multiple pain and gastrointestinal complaints that have responded poorly to treatment, morbid obesity, chronic tiredness, irritability, and Cluster B personality traits. Ms. D is lonely, unemployed, and seems to be in perpetual crisis. She states “unless someone does something to make this better, I just might kill myself.” She blames Dr. B for failing to adequately treat her depression; he has tried many medications to no avail. In psychotherapy sessions, Ms. D complains instead of examining methods for improvement, and she does not complete psychotherapy homework. She is extremely passive in her approach to getting better.

Ms. D asks Dr. B fill out the necessary paperwork so she can qualify for disability. Dr. B informs her that he will not do so because he believes she is capable of employment and that receiving disability would make her less likely to improve. Ms. D and her parents file letters of complaint about Dr. B to the supervisor of the psychiatric clinic for lack of treatment efficacy and for not supporting her disability claim. Dr. B dreads seeing Ms. D on his appointment list, and realizes she repulses him.

Although “the difficult patient” is not a diagnosis or specific clinical entity, clinicians universally struggle with such patients and have an immediate sense of shared experience when describing the phenomenon. In primary care, O’Dowd 1 aptly described this type of patient as the “heartsink” patient, meaning the practitioner often feels exasperation, defeat, or dislike when he or she sees the patient’s name on the schedule.

This article discusses the literature on this topic and provides strategies for dealing with difficult patients in psychiatric practice.

Patient characteristics

Most published reports of difficult patients involve descriptive case series or physician accounts, most often describing patients presenting in nonpsychiatric specialties, including family practice, emergency medicine, rheumatology, gastroenterology, plastic surgery, and dentistry, among others. 2-7

In a survey of physicians in 4 primary care clinics, subjects rated 96 (15%) of 627 adult patients as “difficult.” 8 Difficult patients were significantly more likely than others to have a mental disorder ( Table 1 ). 8 They also had more functional impairment, higher health care utilization, and lower satisfaction with care.

A separate primary care clinic study found uncannily similar results—physicians rated 74 (15%) of 500 new walk-in patients as “difficult.” 9 Compared with other patients, the difficult patients had:

  • higher rates of psychiatric illness, somatization (>5 somatic complaints), and more severe symptoms
  • poorer functional status, more unmet expectations, less satisfaction with care, and higher use of health services.

In addition, physicians with a “poor attitude” toward psychosocial problems were much more likely to rate an encounter as difficult.

Fewer articles on difficult patients have been published in psychiatric literature, although some commonalities have emerged ( Box ). 10-12 Often suffering from chronic conditions without well-defined treatment endpoints, difficult patients do worse clinically, have higher use of health services, and are less happy with their care than other patients.

Difficult patients challenge our competence as physicians and evoke personal distress. Physicians with less job satisfaction, less clinical experience, less training in counseling, and a poor attitude toward psychosocial problems are more likely to perceive a patient as difficult. 13,14

Table 1

Common psychiatric disorders in difficult patients

Multisomatoform disorder

Panic disorder

Generalized anxiety disorder

Major depressive disorder

Alcohol abuse or dependence*

*Researchers categorized patients as having “probable” alcohol abuse or dependence but did not determine if they met DSM-IV-TR criteria for these disorders

Source: Reference 8

Why certain patient types evoke negative reactions

An Ovid Medline search of psychiatric literature for “difficult patients” found only 9 articles published from 1996 to 2008, and most were editorials or essays. 10

Groves 11 grouped difficult patients into 4 categories:

  • dependent clingers
  • entitled demanders
  • manipulative help-rejecters
  • self-destructive deniers.

For a description of the behaviors and personality traits associated with each of these 4 categories and strategies to address them, see “The nurse who worked the system,” Current Psychiatry, July 2009. Groves emphasized that a physician’s negative reactions evoked by such patients—once understood through introspection—may facilitate better understanding and psychological management in their care.

Hinshelwood 12 wrote about the cognitive dissonance psychiatrists encounter when trying to balance the different responses evoked by patients with schizophrenia and severe personality disorders.

When confronted with a psychotic patient’s severely damaged reality testing, psychiatrists often depersonalize the patient in an effort to be “scientific.” Conversely, patients with severe personality disorders threaten the psychiatrist with their emotional instability. The psychiatrist loses the role of objective observer and instead becomes a “moral evaluator,” seeing the patient as “good” or “bad” instead of as a person in need of help.

Hinshelwood cautioned that patients such as this are difficult not because their treatment is complicated but because they challenge our identity as scientists and put us in personal difficulty.

Survival strategies for clinicians

Eight strategies can help improve your care of difficult patients ( Table 2 ).

Table 2

8 strategies for managing difficult patients

1. Acknowledge that the patient is difficult

2. Develop empathy

3. Seek out supervision/consultation

4. Utilize a team approach

5. Lower treatment goals

6. Decompress the treatment timeline

7. Use ‘plussing’ (positive comments and acknowledgements)

8. Use imagery (visualize the patient as a character in an unfinished novel)

1. Acknowledge that the patient is difficult. Allowing yourself to acknowledge that the patient is difficult will enable you to exhale and relax in your approach. Denying that you are frustrated can lead to unconscious actions with bad results for the patient. For example, a psychiatrist in denial of his or her aversion to a chronically suicidal patient may unconsciously forget appointments or signal messages of rejection during a session. The patient may consciously or unconsciously sense abandonment, which can precipitate a crisis. 15

2. Develop empathy. Empathy is identification with and understanding of why a person feels, thinks, and acts as he or she does. The best way to develop empathy for a difficult patient is to learn about him or her firsthand—directly from the patient, not from reading chart notes or from information passed among colleagues.

Learning about the patient firsthand means shifting from sign-and-symptom gathering to performing a genuine inquiry about how the person thinks or feels, including interests, loves, or background. Challenging clinical circumstances—such as seeing a patient in a busy emergency department or during a 15-minute medication check—can make this difficult. In some cases, however, the time needed to establish empathy can be surprisingly brief.

When I meet a patient for the first time, I always begin the conversation as if I wanted to write a brief, positive “bio” of who he or she is. This involves purposefully avoiding questions about pathology. First impressions are powerful in guiding future relationships, and clinicians can cultivate empathy in a natural process by learning about the patient as a person and not as a clinical entity.

The more patients feel that the psychiatrist is “on their level,” the less likely they are to project internalized anguish or impulsively act on conflicted feelings.

3. Seek out supervision or consultation. You can gain new perspectives by taking a “step back” and looking at the case with a colleague. Seeking out consultation also allows you to decompress by “getting it off your chest.” Supervision often allows clinicians to develop:

  • empathy toward a difficult patient
  • increased energy and creativity in subsequent sessions.

4. Utilize a team approach. Difficult patients are exhausting. When possible, having a team rather than an individual responsible for a difficult patient’s care can diffuse the patient’s dysphoric intensity and decrease “targeting” of 1 clinician. In addition, the shared experience of carrying a difficult patient lightens the secondary trauma for individual clinicians.

If you cannot utilize a team to carry out treatment, this approach still may help you develop a treatment plan.

5. Lower treatment goals. The nature of difficult patients makes complete “cures” a rarity. A psychiatrist whose goal is to substantially help a patient may become chronically frustrated and feel inadequate in the face of a patient’s perpetual suffering. The clinician sometimes reacts by developing therapeutic nihilism and withdrawing energy from the case. The patient, of course, senses this and increases his or her general distress level, which intensifies the negative interaction.

By lowering goals—for example, aiming for stabilization rather than improvement—you can feel less like a failure and be more relaxed. A relaxed clinician is more tolerant and in a better position to help the patient. Other lowered goals might be to reduce harm from impulsive or dangerous behaviors instead of eliminating them or better coping with symptoms rather than symptom remission.

6. Decompress the treatment timeline. Difficult patients typically have chronic symptoms that respond poorly to treatment. The clinician who understands that he or she is unlikely to rapidly reduce or eliminate the patient’s symptoms can relax, focus on developing empathy, and help with immediate coping plans that don’t focus on solving long-term problems. Visualizing a treatment plan that has years instead of weeks as markers on the timeline can help you accomplish this.

7. Use ‘plussing.’ Because we experience dread with difficult patients, clinicians often avoid, refrain from, or simply don’t see opportunities to use positive comments and acknowledgements (“plussing”) when they arise. Most patients (as well as clinicians) want to be liked, and small compliments—when genuinely and appropriately placed—sometimes can make a huge difference in patients’ willingness to cope or try new things.

8. Use imagery. Visualize your patient as the central character in an unfinished novel about his or her life. You are in the book as well. Imagine that you are somewhere in the middle of reading this novel. As the once-removed passive reader, you can enjoy the rich, complex nature of the characters and their interactions without feeling overwhelmed by responsibility. You are much better able to accept that your patient is just 1 character, influenced by a myriad of factors other than you. As a character yourself, you are keenly aware of your strengths and weaknesses.

This technique might allow you to see the humorous side of yourself as the hardworking, well-intentioned yet ineffectual psychiatrist. You don’t know how the story will unfold, but you can accept this as you would in any other unfinished novel.

CASE CONTINUED: A more effective approach

Dr. B realizes Ms. D is a difficult patient for him and takes the case into supervision. He is stunned when he is unable to answer several of his supervisor’s questions about Ms. D, including “What was her upbringing like?” and “What are her strengths or interests?” He realizes he knows little about Ms. D and becomes aware that he has focused most of their sessions on either fixing her immediate and never-ending crises or defending himself.

The supervisor points out that Dr. B’s lack of empathy for Ms. D keeps him from helping her—being anxious and defensive makes him less likely to be supportive or creative. Dr. B feels better after the supervision session. He experiences some catharsis and develops a plan to improve the situation.

Did you miss this content?
Avoiding common drug−drug interactions


Poop kills.

If you’re wondering whether I’ve lost my mind, I haven’t: it kills by the millions. On average, 1.8 million people die every year from diarrheal disease caused by poor sanitation and contaminated water supplies. Ninety percent of these deaths are children under five.

The World Health Organization (WHO) registers more than 2 billion cases of diarrheal disease every year, with the most acute cases affecting children under two years old in the developing world. Lack of access to clean sources of water and proper sanitation deprives millions of people of health, dignity and quality of life.

Just a century ago, these same problems afflicted cities like New York, London and Paris. Each metropolis teemed with infectious diseases killing nearly the same number of children that die in sub-Saharan Africa today (check out a History Channel documentary on the topic here).

Essentially, sweeping reforms in water and sanitation allowed these world cities to continue developing. A recent British Medical Journal poll of over 11,000 doctors picked piped water and sewer infrastructure as the most important public health interventions since 1840. Given this success, why has the “sanitation revolution” not yet circled the globe?

Of the two problems, access to clean water has improved the most. Right now, 87% of the world’s population and 84% of the developing world has access to potable drinking water. According to UNICEF and the WHO, households in this group are connected to main water supplies, have secure access to dug wells or springs, or can reliably collect clean rainwater.

This means the world is on track to halve the number of households without access to safe drinking water by 2015 -- one of the high-profile Millennium Development Goals set forth in 2000. That said, water safety is not measured the same way across the board, and policymakers have clearly favored expanding access over ensuring water quality.

A prime example is Honduras. Currently, 86% of households there have access to so-called “improved” water, but only 15% of rural households have access to drinkable water, and only 43% of the total population has access to filtered water. Without filtration and treatment, water is regularly contaminated by microbial bacteria like E. Coli and hazardous waste.

Households with no access to water are left to fend for themselves. As a result, many people in these communities -- almost exclusively rural women and girls -- are forced to spend hours every day collecting water from distant, often toxic sources. This is time not spent caring for family, generating income or going to school.

The situation in slums surrounding cities in developing countries is doubly harsh. Many residents have no access to piped water -- and the water that is available often comes from government authorized cistern trucks that travel door-to-door or standpipes miles away. Local governments allow vendors to buy water at a subsidized price and resell it at a premium. Because demand always outstrips supply, these vendors operate free of regulations and inspections, usually charging a highly-inflated price for unsafe water. The cost of buying water regularly exceeds $1 a day, representing more than half an average day’s income for poor households.

While gains have been made with water, sanitation is lagging behind. At the current rate of growth, access to proper sanitation falls woefully short of Millennium Development Goal targets. To date, more than 2.6 billion people still lack access to improved sanitation services. As defined by UNICEF, this includes access to public sewers or septic tanks, as well as pour-flush or ventilated pit latrines.

The disparity between those who have access to sanitation and those who don’t is massive. Ninety-five percent of households without access are located in Southeast Asia, and in East and sub-Saharan Africa. In these regions, governments allocate only 1 to 2% of the annual budget to low-cost solutions, while spending much more on improving urban sanitation systems for wealthy customers.

Without access to sanitation, poor households have to get by however they can. They use fields, streams, plastic bags, buckets, and unventilated latrines. Few have soap. This results in the rapid spread of fecal-related diseases, causing life-threatening diarrhea and stigmatizing the poor as dirty and unwashed. This feedback cycle infiltrates every aspect of daily life for the poor, leading to environmental degradation, missed days of work and school, and lower income.

But there is hope. Governments have begun to catch onto the link between sanitation and economic development, and are investing accordingly. South Africa’s government, for example, has pioneered a “joined-up thinking” approach to national sanitation policy. This strategy assigns sanitation development and implementation to various actors, including NGOs, local councils and private companies with clearly defined roles and responsibilities. Because sanitation touches everyone, this multi-sector approach is designed to address the institutional and behavioral changes that need to be made.

After all, it isn’t that impoverished households don’t want to be cleaner. The desire for change -- especially at the community level -- has proven to be the most powerful weapon against poor sanitation. Beyond building toilets, these comprehensive local approaches have galvanized whole communities to take ownership of sanitation projects and make sure they succeed.

At Kiva, we believe that major impact starts with small financial interventions and community-level innovations. For this reason, we support Water.org and its efforts to provide micro-credit for households to improve their own water and sanitation systems.To learn more about what this organization is doing, click here.

While water and sanitation projects face unique challenges, the goal to expand access to both is necessary to achieve equitable and inclusive economic growth. Communities have a right to privacy, dignity, health and productivity.

We will continue to discuss issues related to water and sanitation during this blog series. We’ll also highlight a number of our field partners, like Sodis in Bolivia, that are working to finance related projects.

photos courtesy of JJ Casas, Sustainable Sanitation, Barefoot College and Mike Bailey-Gates

<< Kiva Updates