Phytoplankton samples were collected on October 1, 2025 at Bullock’s Reach and analyzed in the laboratory shortly after collection.
It was sunny and breezy on this day. The water temperature was 20.14 °C, the salinity was 30.14 psu, and the chlorophyll a was 4.28 ug/L.
The qualitative tow net sample had a short to moderate filtration time. The filtrate was dark brown and contained some jellyfish.
The analysis of the quantitative whole water sample revealed a total of 509,000 cells/L. The microflagellates were found at 197,000 cells/L. The most predominant phytoplankton genera were Cerataulina spp. at 85,000 cells/L, Chaetoceros spp. at 65,000 cells/L, and Ditylum spp. at 32,000 cells/L.
Thalassiosira is a genus of centric diatoms that are vital primary producers in temperate and polar seas. They can thrive in low temperature and light, as well as mixed waters, which allows them to play a large part in spring diatom blooms. They are also able to defend themselves against zooplankton, allowing them to survive the predation that normally keeps phytoplankton blooms in check.