Hawaii Ocean Time-series (HOT)
in the School of Ocean and Earth Science and Technology at the University of Hawai'i at Manoa
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Unlike the HPLC pigments which are oil soluable, phycoerythrin is a water soluable pigment which can be used as a marker for cyanobacteria such as Trichodesmium spp. Samples were size fractionated through 10µm & 5µm nylon membrane filters, 1L of the filtrate collected, then poured through a 0.4µm poly-carbonate filter. Samples were analyzed using a Turner Designs TD-700 with 544 nm (Ex) and 577 nm (Em) wavelength filters, and the fluorescence obtained. Phycoerythrin was then calculated via the formula:
PE = (fluor - B) / M
where M & B are the slope and intercept respectively of the regression curve obtained by using our pure phycoerythrin stock.
Contour plots of the 0.4µm, 5µm and 10µm fractions of phycoerythrin from 0 to 200 meters are shown in Figure 52. While the > 0.4 µm and > 5 µm fractions do not appear to show any type of seasonality or gradation in the upper ocean, the > 10 µm fraction appears to show a late fall bloom of either Trichodesmium or aggregates containing cyanobacteria.