Regional shifts in phytoplankton abundance, structure, and phenology along the Western Antarctic Peninsula

Printer-friendly version

The western Antarctic Peninsula (WAP) is experiencing dramatic climate change. Warmer, maritime conditions are expand poleward and interact with regional shifts in ocean circulation as well as  local physics and topography. Thus, there is much heterogeneity in the effects of climate on WAP marine ecosystems. In situ observations collected by the Palmer LTER project  have provided three decades of insight  regarding changes in phytoplankton abundance, community structure and primary production seasonally at Palmer station, and spatially during annual cruises across the WAP shelf.  Despite the challenges with cloud cover and high latitude retrieval, satellite-based phytoplankton observations have extended inference from in situ observations and have improved our understanding of ecological pattern and process in this region. Changes in phenology are evident, with spring blooms following the earlier ice retreat. At local scales, deep troughs (or canyons) bisect the continental shelf and act as conduits for warm Upper Circumpolar Deep Water, reduce seasonal ice concentrations, and provide a reservoir of macro and micronutrients, also influencing phytoplankton dynamics. On regional scales, interannual variations in seasonal sea-ice coverage and ocean temperatures result in both latitudinal and cross-shelf gradients in phytoplankton production and community structure.