Climate change is impacting marine ecosystems through physical changes (e.g., increased marine heatwaves, long-term warming) that can manifest biologically at all trophic levels. In the California Current Ecosystem (CCE), a productive and economically important eastern boundary upwelling system, the effects of these physical changes are observed throughout the region from Mexico to Canada. We investigated range expansions into...

The Gerlache Strait is a narrow channel that separates the western coast of the Antarctic Peninsula (WAP) from the Palmer Archipelago. This area is characterized by the presence of interconnected fjords, bays, islands, and channels that serve as a refuge for megafauna during summer. Through the framework of FjordPhyto – a citizen science collaboration with the International Association of Antarctica Tour Operators (IAATO) vess...

Interactions between phytoplankton and ultraviolet radiation (UVR: 280 – 400 nm) are undergoing changes dictated by variability in ocean temperature, the depth of mixed layers, nutrient availability, and the thickness of the ozone layer. There are a variety of mechanisms for phytoplankton to cope with UVR stress, one of the most prevalent being the presence of mycosporine-like amino acids (MAAs). Despite the importance of thes...

Greenland’s coastal margins are influenced by the confluence of Arctic and Atlantic waters, sea ice, icebergs, and meltwater from the ice sheet. Hundreds of spectacular glacial fjords cut through the coastline and support thriving marine ecosystems and, in some places, adjacent Greenlandic communities. Rising air and ocean temperatures, as well as glacier and sea-ice retreat, are impacting the conditions that support these sys...

In the nearshore coastal waters along the Antarctic Peninsula, a recurrent shift in phytoplankton community structure, from diatoms to cryptophytes, has been documented. The shift was observed in consecutive years (1991–1996) during the austral summer and was correlated in time and space with glacial melt‐water runoff and reduced surface water salinities. Elevated temperatures along the Peninsula will increase the extent of co...

Experimental work with cultures of the red tide dinoflagellate Lingulodinium polyedrum suggested mycosporine‐like amino acids (MAAs) are a component of the organic matter excreted by cells. MAAs in dissolved organic matter (DOM) also may have a large influence on absorption of ultraviolet (UV) light through the water column. To test these hypotheses in a natural setting, data were collected from March 1995 through April 1996 i...

Growth rates of late furcilia and juvenile Antarctic krill ( Euphausia superba Dana) in the spring and summer were related to food quantity and quality. The 4 yr covered by this study (1991–1992, 1993–1994, 1994–1995, and 1995–1996) were part of the seasonal time series of the Palmer Long‐Term Ecological Research program. Chlorophyll a concentrations represented food quantity, and accessory photosynthetic pigments represented...