In This Issue

Baleen whale excreta and marine food websPhytoplankton, which forms the base of marine food webs, is often limited by low essential nutrient concentrations in surface waters.Whales are known to recycle and release nutrients, but the impact of whales on primary production by phytoplankton is not wellunderstood.Carla Freitas et al. quantified the nutrients released by baleen whales via feces and urine across high-latitude feeding grounds in the Nordic and Barents Seas.The authors measured the concentration of nutrients in excreta from minke (Balaenoptera acutorostrata) and fin (Balaenoptera physalus) whales and inferred nutrient values for sei (Balaenoptera borealis), humpback (Megaptera novaeangliae), blue (Balaenoptera musculus), and bowhead (Balaena mysticetus) whales.The analysis showed that whales release nitrogen primarily through urine, whereas most phosphorus and trace elements, including iron, zinc, copper, and manganese, are released through fecal plumes.Ecosystem modeling indicated that nutrients recycled by whales increased net primary production in the study area, with effects varying across space and time.The greatest impact was found during the summer, when waters are stratified, and in nutrient-poor offshore regions, with net primary production increasing by up to 10%.According to the authors, the findings suggest that baleen whales exert an underappreciated, cascading influence on marine food webs.-M.H.