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Michelle with her poster

Michelle McCarthy

Navajo Technical University

Research Mentor: David Kimmel and Colleen Harpold

Project: Trends and Variability in Chlorophyll Concentrations in the Southeastern Bering Sea During Record Low Ice

My name is Michelle McCarthy, I am studying Environmental Science with an emphasis in Natural Resources at Navajo Technical University. This summer, I had the opportunity to participate in a research project through the Joint Institute for the Study of the Atmosphere and Ocean. I worked with Dr. David Kimmel and Colleen Harpold at National Oceanic and Atmospheric Administration (NOAA) in the National Marine Fisheries Service (NMFS)/Alaska Fisheries Science Center- Sand Point.

 The research project I worked on with my mentors was to compile data from spring/fall 2018 cruise that collected chlorophyll samples in the Southeastern Bering Sea (BS). With those samples I developed a historic time series that showed the differences in concentrations of chlorophyll blooms. The focus of my project was to find and explain the trends that occurred from record low sea ice to chlorophyll values in 2016.

 At sea, water samples were collected along the 70m isobath from Niskin bottles mounted on a standard CTD rosette system during spring and late summer/early autumn. Samples were collected from discrete water depths (0 to 50m at 10m intervals) and filtered through Whatman GF/F filters (nominal pore size 0.7 um) to estimate total Chlorophyll a. Filters were frozen at sea and analyzed in the laboratory within 12 months using Trilogy Fluorometer.

 We found evidence of a bloom in both spring and fall of 2016 but not in 2018. However using satellite data we found that the bloom occurred later in the year, though chlorophyll concentrations were low. Our results suggest early ice retreat is linked to smaller and later blooms in spring. If this persists it will have large scale impacts on the BS food web.

 Overall, I learned a lot this summer and would like to thank Dave and Colleen for their scientific knowledge. And JISAO for funding my internship experience in the PNW.

Michelle's research poster