  We report a laboratory investigation of weak turbulence of water surface
waves in the gravity-capillary crossover. By using time-space resolved
profilometry and a bicoherence analysis, we observe that the nonlinear
processes involve 3-wave resonant interactions. By studying the solutions of
the resonance conditions we show that the nonlinear interaction is dominantly
1D and involves collinear wave vectors. Furthermore taking into account the
spectral widening due to weak nonlinearity explains that nonlocal interactions
are possible between a gravity wave and high frequency capillary ones. We
observe also that nonlinear 3-wave coupling is possible among gravity waves and
we raise the question of the relevance of this mechanism for oceanic waves.
