The marine system of the West Antarctic Peninsula: status and strategy for progress

Abstract

One contribution of 14 to a theme issue 'The marine system of the West Antarctic Peninsula: status and strategy for progress in a region of rapid change'.

Evidence for the Impact of Climate Change on Primary Producers in the Southern Ocean

“…To date, the most consistent long-term observations of phytoplankton and factors affecting primary production have been made from coastal research stations, notably along the coastal West Antarctic Peninsula as part of the Long Term Ecological Research Network (LTER; Montes-Hugo et al, 2009;Moreau et al, 2015;Kim et al, 2018;Brown et al, 2019). Over the 20-year LTER record, Kim et al (2018) found significant positive trends in chl-a at some field stations on the Antarctic Peninsula but decreasing phytoplankton biomass at others. Our study shows increases in chl-a along the West Antarctic Peninsula (Figure 2) but the spatial scale of the satellite data is coarser and unreliable within a few km of the shore.…”

“…Unlike most of the world's oceans, the vast majority of the Southern Ocean is considered to be replete with nitrate and instead, silicate and iron are limiting in some areas and seasons (Banse, 1996;Boyd et al, 2012Boyd et al, , 2001Hiscock et al, 2003;Doblin et al, 2011). Irradiance can also be crucial to primary production (Deppeler and Davidson, 2017;Kim et al, 2018) and microbial community composition (Arrigo et al, 2010;Kropuenske et al, 2010;Van de Poll et al, 2011;Trimborn et al, 2017) in the Southern Ocean, and irradiance, iron and nutrient availability interact in ways not fully understood at present (Strzepek et al, 2012;Luxem et al, 2017;Trimborn et al, 2019). Further complexities arise from colimitation by iron and other micronutrients (e.g., Mn; Pausch et al, 2019).…”

Physical and Biogeochemical Regionalization of the Southern Ocean and the CCAMLR Zone 48.1

“…Changes in dissolved iron supply, light availability, stratification and ice-free period are projected to affect the biogeochemical cycles and increase Southern Ocean NPP rates up to 50%, in contrast with global trend of declining NPP (Henley et al, 2020). Sea ice variability also influence the production of dimethyl sulfide, a climate-active gas with high concentration in the marginal ice zone (Meredith et al, 2017;Hendry et al, 2018;Henley et al, 2019), and plays an important role in controlling the amount of organic matter that reaches the benthic community (Hendry et al, 2018;Henley et al, 2019). The strong interdependency between sea ice and phytoplankton abundance and size spectrum implies that its variability is also able to alter higher trophic levels of the food web, changing the structure and functioning of the entire ecosystem (Kerr et al, 2018).…”

“…The 48.1 zone of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is a key region for monitoring the Antarctic ecosystem. This area is experimenting strong interannual variability and trends in sea ice coverage and water column temperature (Schmidtko et al, 2014;Jones et al, 2016) that turn this zone in one of the most climate sensitive region of the planet and most variable (Hendry et al, 2018). Recent studies (Murphy et al, 2016;Comiso et al, 2017) suggested that the interannual oceanographic variability is partly linked with atmospheric patterns, such as El Niño-Southern Oscillation and the Southern Annular Mode.…”

“…The terrestrial ice-free area of Antarctica was divided in 16 biogeographic regions by Terauds and Lee (2016), whereas various studies of bioregionalization have been previously performed for the Southern Ocean pelagic (i.e., Grant et al, 2006;Spalding et al, 2007Spalding et al, , 2012Cabré et al, 2016) and benthic communities (Griffiths et al, 2009;Pierrat et al, 2013;Douglass et al, 2014;Hogg et al, 2016;Teschke et al, 2016;Fabri-Ruiz et al, 2020). A new physical and biogeochemical regionalization is needed to fill the existing gap in the understanding of the physical forcing on biogeochemical cycles spatial heterogeneity (Hendry et al, 2018) and to generate useful information for marine protected areas proposals and marine ecosystem modeling.…”