Northern Antarctic Peninsula: a marine climate hotspot of rapid changes on ecosystems and ocean dynamics

Kerr, Rodrigo; Mata, Maurício M.; Mendes, Carlos; Secchi, Eduardo R.

doi:10.1016/j.dsr2.2018.05.006

Cited by 55 publications

(60 citation statements)

References 65 publications

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“…The Northern Antarctic Peninsula (NAP), which encompasses the Gerlache and Bransfield Straits, the southernmost sector of the Drake Passage, the northwestern Weddell Sea and the regions offshore of the western Antarctic Peninsula, is a good example of how environmental changes can alter and transform the polar ecosystem through time (Kerr et al 2018c and references therein). This is a highly productive area and a key-feeding region for whales (e.g., Dalla Rosa et al 2008;Nowacek et al 2011;Secchi et al 2011;Seyboth et al 2018) and other krill-feeding predators (e.g., Trivelpiece et al 2011;Southwell et al 2012).…”

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Dynamics of an intense diatom bloom in the Northern Antarctic Peninsula, February 2016

Costa

Mendes

Tavano

et al. 2020

Limnology & Oceanography

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Diatoms are considered the main base of the Southern Ocean food web as they are responsible for more than 85% of its annual primary production and play a crucial role in the Antarctic trophic structure and in the biogeochemical cycles. Within this context, an intense diatom bloom reaching > 45 mg m−3 of chlorophyll a was registered in the Northern Antarctic Peninsula (NAP) during a late summer study in February 2016. Given that nutrient concentrations and grazing activities were not identified here as limiting factors on the bloom development, the aim of this study was to evaluate the effect of water column structure (stability and upper mixed layer depth) on the phytoplankton biomass and composition in the NAP. The diatom bloom, mainly composed by the large centric Odontella weissflogii (mostly > 70 μm in length), was associated with a local ocean carbon dioxide uptake that reached values greater than −60 mmol m−2 d−1. We hypothesize that the presence of a vertically large water column stability barrier, just below the pycnocline, was the main driver allowing for the development of the intense diatom bloom, particularly in the Gerlache Strait. Contrarily, a shift from diatoms to dinoflagellates (mainly Gymnodiniales < 20 μm) was observed associated with conditions of a highly stable thin layer. The results suggest that a large fraction of this intense diatom bloom is in fast sinking process, associated with low grazing pressure, showing a crucial role of diatoms for the efficiency of the biological carbon pump in this region.

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Dynamics of an intense diatom bloom in the Northern Antarctic Peninsula, February 2016

Costa

Mendes

Tavano

et al. 2020

Limnology & Oceanography

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“…Six main projects were carried out by the GOAL from 2003 to 2019 in the NAP area: REDE-1 (Mata and Garcia, 2016a,b,c), SOS-CLIMATE (Mata and Garcia, 2016d,e,f), POLARCANION/PRO-OASIS (Mata and Kerr, 2016a,b,c), and 105 NAUTILUS/INTERBIOTA (Kerr et al, 2018a and references therein; Table 1). Most of the cruises covered the Bransfield and Gerlache straits, followed by the Bellingshausen Sea during the NAUTILUS/INTERBIOTA projects and the northwestern Weddell Sea during the SOS-CLIMATE project (Table 1 and Fig.…”

Section: Hydrographic Cruises Data Sampling and Ancillary Data Setmentioning

confidence: 99%

“…Most climatological products are built to represent the global ocean and its large-scale basins, such as the Southern Ocean. The NAP, on the other hand, is a relatively small region but highly dynamical and ecologically important to connect 300 regional environments (Kerr et al, 2018a). In this context, we now compare the GOAL gridded product with some other available gridded products, widely used by the ocean community, to show how effective is to have regional climatologies, especially in areas of intense spatial and temporal variability.…”

Section: Comparison Against Other Climatological Productsmentioning

confidence: 99%

A novel hydrographic gridded data set for the Northern Antarctic Peninsula

Dotto¹,

Mata²,

Kerr³

et al. 2020

Preprint

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Abstract. The Northern Antarctic Peninsula (NAP) is a highly dynamic transitional zone between the subpolar-polar and oceanic-coastal environments, and it is located in an area affected by intense climate change, including intensification and spatial shifts of the westerlies as well as atmospheric and oceanic warming. In the NAP area, the water masses originate mainly from the Bellingshausen and Weddell Seas, which create a marked regional dichotomic thermohaline characteristic. Although the NAP area has relatively easy access when compared to other Southern Ocean environments, our understanding of the water masses distribution and the dynamical processes affecting the variability of the region is still limited. That limitation is closely linked to the sparse data coverage, as commonly is the case in most of the Southern Ocean environments. This work provides a novel three-dimensional high-resolution hydrographic gridded data set for the NAP, namely the GOAL gridded product. Hydrographic measurements from 2003–2019 have been optimally interpolated to produce maps of conservative temperature, absolute salinity, neutral density and dissolved oxygen at ~10 km spatial resolution and 114 depth levels. The water masses and oceanographic features in this regional gridded product are more accurate than other climatologies and state estimate products currently available. The data sets are available in netCDF format at https://www.goal.furg.br/producao-cientifica/supplements/203-goal-gridded-nap and at https://doi.org/10.5281/zenodo.3989548 (Dotto et al., 2020). The novel GOAL gridded product and comprehensive data sets presented here are a valuable tool to be used in studies addressing climatological changes in the unique NAP region since they provide accurate initial conditions for ocean models and improve the early 21st-century ocean mean-summer-state representation for that area.

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“…The rapid warming of winter air temperature and sea surface temperature resulted in declining perennial and seasonal sea-ice extent and duration [5][6][7][8][9] . Since this warming effect is more pronounced in the northern half of the peninsula, the latitudinal climate gradient with warmer, humid conditions in the north but a cold-dry polar-type continental climate in the south has become steeper [7][8][9] . These alterations have caused considerable changes in the phytoplankton community 2,10 .…”

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“…The observed changes in the abiotic environment and phytoplankton community structure have a strong potential to influence reproduction, recruitment and distribution of key grazers such as Euphausia superba (krill hereafter) and the salp Salpa thompsoni (salps) due to a strong bottom-up control of the system 9 . The temporal and spatial fluctuations in the abundance of krill and salps are commonly assigned to water temperatur, the timing of sea-ice advance, duration of sea-ice cover and food availability 13,14 .…”

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Krill vs salps: dominance shift from krill to salps is associated with higher dissolved N:P ratios

Plum

Hillebrand

Moorthi

2020

Sci Rep

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pronounced atmospheric and oceanic warming along the West Antarctic peninsula (WAp) has resulted in abundance shifts in populations of Antarctic krill and Salpa thompsoni determined by changes in the timing of sea-ice advance, the duration of sea-ice cover and food availability. Krill and salps represent the most important macrozooplankton grazers at the WAP, but differ profoundly in their feeding biology, population dynamics and stoichiometry of excretion products with potential consequences for the relative availability of dissolved nitrogen and phosphorus. Alternation of the dissolved nutrient pool due to shifts in krill and salp densities have been hypothesized but never explicitly tested by using observational data. We therefore used the palmer LteR dataset in order to investigate whether the dominance of either grazer is related with the observed dissolved nitrogen:phosphorus (n:p) ratios at the WAP. Across the whole sampling grid, the dominance of salps over krill was significantly correlated to higher concentrations of both n and p as well as a higher n:p ratios. Using actual long-term data, our study shows for the first time that changes in key grazer dominance may have consequences for the dynamics of dissolved nitrogen and phosphorus at the WAp.

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Northern Antarctic Peninsula: a marine climate hotspot of rapid changes on ecosystems and ocean dynamics

Cited by 55 publications

References 65 publications

Dynamics of an intense diatom bloom in the Northern Antarctic Peninsula, February 2016

Dynamics of an intense diatom bloom in the Northern Antarctic Peninsula, February 2016

A novel hydrographic gridded data set for the Northern Antarctic Peninsula

Krill vs salps: dominance shift from krill to salps is associated with higher dissolved N:P ratios

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