batch_auto_20260713 202607131256465730 BOEM ESP geoESPIS ESPIS@boem.gov Bureau of Ocean Energy Management Marine Arctic Ecosystems Study (MARES) Pilot Program Task 5; Biophysical and Chemical Observations II Stantec Consulting Services Inc. Stantec Consulting Services Inc. The MARES project deployed 4 moorings in the Eastern Beaufort Sea in October 2017, three of which stayed in the water for one year, and one mooring remained until summer of 2019. Five moorings had previously been deployed in fall 2016-2017. The moorings collected data from physical oceanography through to marine mammal vocalizations to better understand drivers and the influence of the Mackenzie outflow on the marine ecosystem in the Study Area. Measurements revealed very large wind driven currents on the shelf and complex patterns of currents at greater depths. The direct measurements of sea ice from the MARES moorings revealed a very dynamic regime of sea ice motion. Zooplankton and Arctic cod biomass coincided with the productive period on the Beaufort Shelf, when sea ice is retreating, ice algal and water column primary production is initiated, and secondary production is ongoing. Detections of marine mammals largely reflected migratory patterns for bowhead and beluga whales, and breeding for bearded seals. Overall, the project contributes continuous records of physical, chemical and biological parameters in the Eastern Beaufort Sea, providing invaluable data to better understand the ecosystem and its drivers and to build further programs. 1131850 U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program https://doi.org/10.13039/100012475 M17PD00006 10.67297/9A1E1C https://boem.gov/awardpages/100252