Long-term studies on West Antarctic Peninsula phytoplankton blooms suggest range shifts between temperate and polar species

ANTONI, JULIETA; ALMANDOZ, GASTÓN O.; GOLDSMIT, JESICA; GARCIA, M.D.; FLORES-MELO, XIMENA; HERNANDO, MARCELO P.; SCHLOSS IRENE RUTH

GLOBAL CHANGE BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2024

1354-1013

The Western Antarctic Peninsula (WAP) experiences one of the highest rates of seasurface warming globally, leading to potential changes in biological communities.Long-termphytoplankton monitoring in Potter Cove (PC, King George Island, SouthShetlands) from the 1990s to 2009 revealed consistently low biomass values, andsporadic blooms dominated by cold-watermicroplankton diatoms. However, a significantchange occurred between 2010 and 2020, marked by a notable increase inintense phytoplankton blooms in the region. During this period, the presence of ananoplankton diatom, Shionodiscus gaarderae, was documented for the first time. Insome instances, this species even dominated the blooms. S. gaarderae is recognizedfor producing blooms in temperate waters in both hemispheres. However, its bloomingin the northern Southern Ocean may suggest either a recent introduction or arange shift associated with rising temperatures in the WAP, a phenomenon previouslyobserved in experimental studies. The presence of S. gaarderae could be viewed as awarning sign of significant changes already underway in the northern WAP planktoncommunities. This includes the potential replacement of microplankton diatoms bysmaller nanoplankton species. This study, based on observations along the past decade,and compared to the previous 20 years, could have far-reachingimplications forthe structure of the Antarctic food web.