Experimental Design

Experiments were conducted during the CORSACS (Controls On Ross Sea Algal Community Structure) expedition in January 2006 to the Ross Sea, Antarctica, onboard the RVIB Nathaniel B. Palmer (cruise NBP-0601). Water was collected at 75.00S, 177.36E using a trace metal clean towed-intake surface water Teflon diaphragm pumping system (Bruland et al., 2005). Water was prescreened through acid-washed 200μm Nitex mesh to eliminate large zooplankton and collected into a 50-L mixing carboy. Collected water was gently mixed and dispensed into 12 4.5-L and 12 2.7-L acid washed trace metal clean clear polycarbonate bottles for incubation. Half of the bottles were spiked with 1.0nM FeCl3 (final concentration) at the beginning of the experiment. Bottles were incubated in two temperature controlled deck-board incubators (Feng et al., 2009; Hare et al., 2007). Incubators were screened to 18% of Io using two layers of neutral density filter. One incubator was kept at ambient temperature (0 deg C), while the temperature in the other was gradually increased to 4 deg C over the course of 24 h. Bottles were incubated for seven days. The 4.5-L bottles were sampled daily and the 2.7-L bottles were only sampled on the final day of the experiment. All sampling occurred under a laminar flow hood using trace metal clean techniques.

References

Bruland, K.W., E.L. Rue, G.J. Smith, and G.R. DiTullio. 2005. Iron, macronutrients and diatom blooms in the Peru upwelling regime: brown and blue waters of Peru. Marine Chemistry 93: 81-103.

Feng, Y., C.E. Hare, K. Leblanc, G.R. DiTullio, P.A. Lee, S.W. Wilhelm, J. Sun, J.M. Rose, N. Nemcek, I. Benner, and D.A. Hutchins. 2009. The effects of increased pCO2 and temperature on the North Atlantic Spring Bloom: I. The phytoplankton community and biogeochemical response. Marine Ecology Progress Series 388: 13-25.

Hare, C.E., K. Leblanc, G.R. DiTullio, R.M. Kudela, Y. Zhang, P.A. Lee, S.F. Riseman, and D.A. Hutchins. 2007. Consequences of increased temperature and CO2 for phytoplankton community structure in the Bering Sea. Marine Ecology Progress Series 352: 9-16.

nuts_disslv_ant1.csv