Love lobster? Crab? Swordfish? The larvae (just hatched) stages of these tasty marine species spend their early development floating as part of zooplankton community. Their limited ability to move means that they drift wherever the currents take them, leaving them uniquely vulnerable and unable to escape devastating events such as oil spills or even just the noise associated with searching for new offshore oil reserves.
Published today in Nature, the science is in – the noise from the airguns used in seismic exploration for offshore oil has been shown to have devastating effects on zooplankton. The team of researchers found significant damage to zooplankton up to 3/4 mile away from the source:
Experimental air gun signal exposure decreased zooplankton abundance when compared with controls, as measured by sonar (~3–4 dB drop within 15–30 min) and net tows (median 64% decrease within 1 h), and caused a two- to threefold increase in dead adult and larval zooplankton.
Impacts were observed out to the maximum 1.2 km range sampled, which was more than two orders of magnitude greater than the previously assumed impact range of 10 m. Although no adult krill were present, all larval krill were killed after air gun passage.
There is a significant and unacknowledged potential for ocean ecosystem function and productivity to be negatively impacted by present seismic technology.
The significance and implications of potential large-scale modification of plankton community structure and abundance due to seismic survey operations has enormous ramifications for larval recruitment processes, all higher order predators and ocean health in general.
There is an urgent need to conduct further study to mitigate, model and understand potential impacts on plankton and the marine environment, and to prioritize development and testing of alternative seismic sources.
Plankton also supply half of the oxygen we breathe and are the base of the ocean food web – with less plankton there is less for fish to eat at a time when the world is increasingly looking to the ocean to provide food.
The planned seismic surveys off the Atlantic Coast of the US will have negative effects on the marine life, and eventually will impact the distribution and abundance of seafood. And if you like to fish, you may find it even harder to hook a big one.
NOAA is taking comments until July 6th on the proposed seismic surveys in the Atlantic.