Terrestrial organisms are composed of six major elements, C, H, N, O, P, and S, in addition to more than 50 trace elements. In the ocean, nitrogen (N) and phosphorus (P) are called limiting nutrients because they may be available in concentrations which limit photosynthesis in algae. C, H, O and S typically present in abundance are therefore non-limiting. Silica (Si) is also an important resource for some algae such as diatoms that use it to form their protective shells. For growth, phytoplankton consume the available forms of these elements namely nitrate (NO3), ammonium (NH4+), phosphate (PO42-) and silicate (SiO3–) from the surrounding waters.
Phytoplankton are microscopic plants that thrive in the ocean currents and are the base of the marine food chain. They are an ecosystem indicator and are therefore important to monitor. Phytoplankton, like terrestrial plants, mainly need two things to grow: nutrients (i.e. food) and light.
The GreenEdge project aims to improve our understanding about phytoplankton in the Ice covered Arctic Ocean.
It was to study diatoms, the microalgae that dominate phytoplankton blooms, that the “silica and diatom” team came to Qikiqtarjuaq. To follow the evolution of the phytoplankton bloom, successive Green Edge teams focused their efforts on measuring how fast diatoms form silica shells (frustules) and the rate at which the frustules dissolve. Aude Leynaert was the first to reach the ice camp on May 5, 2016. A month later, Véronique Cornet-Barthaux and Morgane Gallinari took over! Justine Legras, Bernard Quéguiner and Brivaela Moriceauare the last to arrive at the camp!
