The Effects of Environmental Changes in the Northern Gulf of Alaska on the Synthesis of Lipid in N.flemingeri and N.plumchrus from 2018 to 2019

Adrianna Hernandez, Florida International University, Miami, FL, United States and Russell R Hopcroft, University of Alaska Fairbanks, Fairbanks, AK, United States
The storage of lipid is an essential aspect of life in high-latitude copepods that rely on it during periods of diapause, for energy storage, and for reproduction. In the sub-arctic Gulf of Alaska, the amount of lipid within Neocalanus plumchrus and Neocalanus flemingeri is likely dependent on the environmental temperature, food availability/quality, and their residence time in favorable feeding environments. We examined: 1) whether the lipid content from samples of these two species differed, from 2018 to 2019, across the GOA shelf, and 2) compared the lipid content between N. plumchurs and N. flemingeri, and between the different life stages of the animals. Animals were collected using a Calvet net at as many as 12 study sites throughout the GOA shelf. The samples were live sorted and photographed, then the area of the lipid sac, as well as the prosome and height lengths’ of the animals were determined for ~50 animals of each species of their last two subadult life stages. Our results demonstrated that 2018 had bigger animals on average for both species, as well as a greater cross-shelf difference in the amount of lipid within individuals. Additionally, in both years, the N. flemingeri had more lipid than N. plumchrus. We believe that because 2019 was a warmer year on the Gulf relative to 2018, temperature had a significant role in the synthesis of lipid within both species. The data suggests that environmental changes directly affects the amount of lipid present in zooplankton, which can, in turn, have a detrimental consequence on their future reproductive rate, as well as on the overall ocean ecosystem where lipid-rich zooplankton serve as a main food source for many marine species.