​Phytoplankton samples were collected on August 21, 2024 at Bullock Reach and analyzed in the laboratory shortly after collection. It was sunny and breezy on Narragansett Bay. Sonde data revealed the surface water temperature was 22.0°C, salinity was 27.1 psu, and chlorophyll a was 7.0 ug/L. The qualitative tow net sample had a quick filtration time, the filtrate was a light tan color. The analysis of the quantitative whole water sample revealed a total of 433,000 cells/L. The microflagellates were found at 35,000 cells/L. The two most predominant phytoplankton genera were Skeletonema spp. at 84,000 cells/L and Leptocylindrus spp. at 79,000 cells/L. Other representative genera include Ceratulina spp., and Cylindrotheca spp. Today’s featured 200x phase-contrast micrograph shows Chaetoceros curvisetus, a species of marine phytoplankton that is widely distributed and common to North Atlantic waters. Chaetoceros serves as an important food source within the water column and major carbon contributor to the benthic environment. Chaetoceros has been reported to contribute about 91% of total phytoplankton cells serving as an important primary producer within this area.

Phytoplankton samples were collected on July 24, 2024 at Bullock Reach and analyzed in the laboratory shortly after collection. It was a cloudy and humid day on Narragansett Bay. Sonde data revealed the surface water temperature was 24.4°C, salinity was 26.8 psu, and chlorophyll a was 12.8 ug/L. The qualitative tow net sample had a medium filtration time and the filtrate was clear with a light brown color. Some particulates were noted in the filtrate. The analysis of the quantitative whole water sample revealed a total of 1,154,000 cells/L. The microflagellates were found at 672,000 cells/L. The most predominant phytoplankton genus was Eutreptiella spp. at 154,000 cells/L. Other representative genera include Prorocentrum spp. and Heterocapsa spp. Polykrikos spp. is a genus of marine dinoflagellates featured in today’s 200x phase contrast micrograph image. It gets its name from the Greek “poly” – many, and “krikos” – ring or circle. Polykrikos have been found to regulate algal blooms as they feed on toxic dinoflagellates. However, there is also some data available on Polykrikos being toxic to fish.​

​Phytoplankton samples were collected on July 10, 2024 at Bullock Reach and analyzed in the laboratory shortly after collection. Sonde data revealed the surface water temperature was 25.9°C, salinity was 23.6 psu, and chlorophyll a was 5.0 ug/L.  The qualitative tow net sample had a short filtration time, the filtrate was slightly cloudy, and the analyzed sample volume was 500 mL. The analysis of the quantitative whole water sample revealed a total of 999,000 cells/500 mL. The most predominant phytoplankton genus was Skeletonema spp. at 572,000 cells/500mL. Other representative genera include Chaetoceros spp. and Leptocylindrus spp. Ditylum is a genus of marine centric diatoms with a worldwide distribution in boreal, tropical, coastal and estuarine environments and is the feature 200x phase contrast micrograph image for the day. Ditylum spp. have been used as a model organism for genetic studies concerning metapopulation structures and environmental influence on population genetic variability.

​Phytoplankton samples were collected on June 12, 2024 at Bullock Reach and analyzed in the laboratory shortly after collection. Sonde data revealed the surface water temperature was 19.68°C, salinity was 24.22 psu, and chlorophyll a was 9.89 ug/L. The qualitative tow net sample had a short filtration time, and the filtrate was mostly clear. The analysis of the quantitative whole water sample revealed a total of 12,732,000 cells per Liter. The most predominant phytoplankton genus was Skeletonema spp. at 12,408,000 cells/L. Other representative genera include Chaetoceros spp. and Leptocylindrus spp. Prorocentrum spp. (see 200x phase contrast image below) is a dinoflagellate genus containing several toxic and harmful species. P. micans is one of the most common species in the genus. Prorocentrum is found in cold, temperate to tropical waters. This genus forms extensive red tides in many parts of the world, though blooms are usually harmless. It may excrete substances that inhibit diatom growth, but these substances do not enter the food chain or affect organisms at higher trophic levels.