Gulf of Alaska | Lower Trophic Levels
Phytoplankton monitoring in Kachemak Bay, Alaska Presenter: Dominic Hondolero , Dominic.Hondolero@noaa.gov, NOAA Kasitsna Bay Laboratory Martin Renner , Martin.Renner@noaa.gov, NOAA Kasitsna Bay Laboratory Kristine Holderied , Kris.Holderied@noaa.gov, NOAA Kasitsna Bay Laboratory
Kachemak Bay, Alaska is a highly productive, estuarine ecosystem located in southcentral Alaska. Phytoplankton in Kachemak Bay form the base of an extensive food web that supports a productive zooplankton community, diverse invertebrates, migratory seabirds, fishes, and marine mammals such as sea otters and whales. Additionally, Kachemak Bay supports commercial fishing, mariculture, and subsistence harvesting of marine resources. The reliance of so many consumers on the marine food web and phytoplankton as the primary producers has shown the importance of regular long-term monitoring in Kachemak Bay. Since 2012, we have been conducting monitoring in Kachemak Bay as part of the Gulf Watch Alaska long-term monitoring program, funded by the Exxon Valdez Oil Spill Trustee Council and NOAA’s National Centers for Coastal Ocean Science. Several species of harmful phytoplankton have been observed in our sampling including Alexandrium catanella, which can cause Paralytic Shellfish Poisoning (PSP), Pseudo-nitzschia spp. which can cause Amnesic Shellfish Poisoning (ASP), and Dinophysis spp . which can cause Diarrhetic Shellfish Poisoning (DSP). Over the course of our monitoring we have also seen several water discoloration events caused by benign phytoplankton that emphasize the need for regular monitoring and event response when these blooms occur and attract the attention of concerned members of the public. The phytoplankton community in Kachemak Bay shows strong seasonal patterns, with diatom productivity typically peaking in early to mid-summer and, usually, a second dinoflagellate bloom in late summer before the productivity tapers off around October, with cell counts remaining low until the spring bloom begins again in March and April. We are combining this long-term information on phytoplankton population patterns with parallel time series on oceanographic conditions and zooplankton community composition to improve understanding of climate-driven changes in the marine food web.
Alaska Marine Science Symposium 2023 136
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