CORSACS
Methods
We will conduct two cruises to the Ross Sea, one is
summer and one in austral spring, and conduct both experimental and
observational studies. We will sample regions where iron and carbon
dioxide is high, as well as regions where both are low, and determine
the irradiance regime in each. If possible, we will also sample regions
with high iron and reduced CO2 levels, as well as low Fe and high CO2
concentrations (both are relatively unusual states). The observations
should allow us to determine the most important factor in controlling
phytoplankton composition, a major factor in controlling biogeochemical
cycles in the ocean.
We also will sample water and manipulate
CO2, Fe and irradiance levels within deck-board semi-continuous
mesocosms. This will directly test the interactions among the three
variables.
Measured Parameters
Many different measurements were made by the group and include the following:
- Temperature, salinity, density
- Nutrients (nitrate, nitrite, silicate, phosphate, ammonium)
- Iron (dissolved, complexed, particulate), Cobalt, Cadmium
- Chlorophyll (total and < 20 µm)
- Particulate organic carbon, nitrogen and phosphorus
- Biogenic silica
- DMS, DMSP (all pools)
- CO2, pH
- Photosynthetic performance via fluorescence
- Primary production via 14C
- Phytoplankton pigments via HPLC
- Phytoplankton composition via microscopy
- Bacterial and viral abundance
- Photosynthetic responses