A R C T I C I N T E G R A T E D E C O S Y S T E M R E S E A R C H P R O G R A M
Warmer water means smaller, less nutritious zooplankton Zooplankton are the important food items that link phytoplankton with organisms higher in the food web. Some species of zooplankton accumulate large fat reserves that they use to overwinter, and these species are important prey items for juve- nile fishes, seabirds, and marine mammals. During spring, zooplankton are growing and reproducing at nearly their maximum rate. In the warm years of the IERP surveys, fewer large, fat-rich zooplankton were found during late summer compared to earlier in the decade. Zooplankton communities comprised of smaller zooplankton were influenced by increased transport of warmer Bering Sea water and plankton through the Bering Strait, particularly in 2019. These smaller zooplankton are less nutritious prey, having less overall caloric and fat content. Further warming will likely result in the increased importance of smaller zooplankton in Arctic waters as a food item for larger animals.
Harmful algal blooms are likely to increase
Warmer waters will likely increase the frequency and impacts of harmful algal bloom events, with potential ramifications for ecosystem and public health, including subsistence harvesting activi- ties. Large aggregations of dormant phytoplankton cysts known to be associated with harmful algal bloom (HAB) species, specifically the dinoflagellate Alexandrium spp., exist on the seafloor, with active cells observed in overlying waters near Icy Cape in the Chukchi Sea. Toxins from Alexandrium spp. and the diatom Pseudo-nitzschia spp. have been found in zooplankton, seabirds, marine mammals, and benthic invertebrates in this region. Research in this area is expanding and the Alaska Harmful Algal Bloom Network is serving a coordination role.
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