Dataset: March Incubation Chlorophyll a

Multivariate mesocosm experiments were conducted with a natural phytoplankton community from Narragansett Bay, RI. Water was incubated in triplicate at -0.5ºC, 2.6ºC, and 6ºC for 10 days. At each temperature, treatments included both nutrient amendments (N, P, Si addition) and controls (no macronutrients added). For complete methodology, see “The Interactive Effects of Temperature and Nutrients on a Spring Phytoplankton Community” (Anderson et al, in prep).

Community size structure from incubation experiments was assessed using size-fractionated chlorophyll a. At each dilution time point, whole incubation water was filtered in triplicate onto 25 mm Whatman GF/F filters (GE Healthcare), 5 µm polyester filters, or pre-filtered through a 20 µm mesh and then filtered onto 25 mm GF/F filters. This allowed for the calculation of the following size fractions: 0.7-5 µm, 5-20 µm, and >20 µm. Chlorophyll was then extracted in 90% acetone for 24 hours at -20ºC.  Fluorescence was read on a 10-AU fluorometer (Turner Designs) and data was analyzed according to the techniques described in Graff and Rynearson (2011).