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Credit: Russ HopcroftThe coastal Gulf of Alaska water column is becoming progressively more stratified — the entire water column is warming, but more rapidly at the surface than near the seafloor, while near surface waters are becoming fresher. This is due to multiple factors including the air-sea heat flux, ocean heat flux convergences, the stabilizing… Read more »

Credit: Ana Aguilar-IslasReductions in primary producer average cell size and biomass followed the 2015-2016 warming, as did corresponding reductions at higher trophic levels. In addition, southern zooplankton species of smaller body size invaded the region and anomalous increases in gelatinous zooplankton population were observed. These changes, which could represent a window into the future of… Read more »

Credit: NGA LTERAlthough glacial input leads to high iron concentrations during summer and fall within the narrow Alaska Coastal Current, the ratio of iron to nitrate over the Northern Gulf of Alaska shelf in spring can be low enough to lead to nutritional stress in diatoms. This mismatch in essential nutrients likely affects phytoplankton community… Read more »

Credit: Seth DanielsonModeling at NGA LTER investigates how the complex interplay between the strongly seasonal freshwater discharge at the coast and offshore eddies controls horizontal gradients of limiting nutrients (nitrate and iron). This work builds on previous modeling studies in the region that utilized Seward Line observations to improve the accuracy of simulated physical and… Read more »

Credit: PAL LTERShifts in sea ice are affecting the WAP ecosystem and biogeochemistry. Despite dramatic shifts in Antarctic food webs, the number of the keystone krill species (Euphausia superba) has not changed significantly over the PAL LTER study area. However, researchers have observed reduced juvenile recruitment following positive anomalies of the Southern Annular Mode. North… Read more »

Credit: US LTERBetween 2010 and 2017, the PAL LTER study area experienced cooler winter air temperatures, cooler summer surface ocean temperatures, and longer ice seasons relative to the first decade of the 21st century (but not relative to the 1950s-1970s). This has slowed sea ice declines, which is associated with increased primary productivity and ocean… Read more »

Credit: PAL LTERRapid warming in the WAP coincides with increases in gentoo penguin and decreases in Adélie penguin populations. While foraging ranges of Adélies and Gentoos overlap with each other and with krill density maxima near Palmer Station, the vertical grazing ranges of the two penguin species differ . This suggests that declines in Adélie… Read more »

Credit: PAL LTERHumpback whale populations are growing at their biological maximum as they recover from intense  commercial whaling. New cetacean research at PAL LTER shows that humpbacks forage in close proximity to the penguins near Palmer Station, and in similar portions of the water column used by Adélie penguins during critical chick rearing periods. Palmer… Read more »

Credit: PAL and US LTEROver the past five decades, the West Antarctic Peninsula (WAP) has experienced changes related to rapidly warming winter atmospheric temperatures, dramatic sea ice declines, and accelerated glacial melting. Interactions between ocean and atmospheric climate cycles (El Niño, Southern Annual Mode) influence shoreward heat delivery associated with deep warm ocean waters and… Read more »

Credit: Erika ZambelloA 20-year landscape-scale experiment at VCR LTER was the first to show the role of restoration in reestablishing carbon burial in seagrass meadows, which matches natural systems after a decade. Virginia Coast Reserve scientists authored the international protocol through Verified Carbon Standards for issuing seagrass restoration carbon offset credits on the voluntary market…. Read more »