The role of water column stability and wind mixing in the production/export dynamics of two bays in the Western Antarctic Peninsula

Höfer, Juan; Giesecke, Ricardo; Hopwood, Mark J.; Carrera, Vania; Alarcón, Emilio; González, Humberto E.

doi:10.1016/j.pocean.2019.01.005

Cited by 53 publications

(73 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Macronutrient data from Maxwell Bay (King George Island, South Shetland Islands), for example, suggests that Fe from local glaciers mixes with high-NO 3 , high-Si ocean waters, providing ideal conditions for phytoplankton blooms in terms of nutrient availability. The lowest surface macronutrient concentrations measured in Maxwell Bay in a summer campaign were 17 µM NO 3 , 1.4 µM PO 4 , and 47 µM Si (Höfer et al, 2019). Similarly, in…”

Section: Contrasting Fe and No 3 Limited Regions Of The Oceanmentioning

confidence: 85%

“…5). High-NO 3 , low-Fe water can be found in the immediate vicinity of Antarctica's coastline (Gerringa et al, 2012;Marsay et al, 2017), and even in inshore bays (Annett et al, 2015;Höfer et al, 2019).…”

Section: Contrasting Fe and No 3 Limited Regions Of The Oceanmentioning

confidence: 99%

“…For a hypothetical nutrient-flux from a glacier, the same flux could be envisaged in two endmember scenarios; one several kilometres inside an Arctic fjord (e.g. Godthåbsfjord or Kongsfjorden) and one at the coastline of an isolated Southern Ocean island such as the Kerguelen (Bucciarelli et al, 2001) or South Shetland Islands (Höfer et al, 2019). In the Arctic fjord, a pronounced Fe flux from a summertime discharge would likely have no immediate positive effect upon fjord-scale marine primary production because Fe may already be replete (Hopwood et al, 2016;Crusius et al, 2017).…”

Section: Contrasting Fe and No 3 Limited Regions Of The Oceanmentioning

confidence: 99%

See 2 more Smart Citations

Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

Hopwood¹,

Carroll²,

Dunse³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Freshwater discharge from glaciers is increasing across the Artic in response to anthropogenic climate change, which raises questions about the potential downstream effects in the marine environment. Whilst a combination of long-term monitoring programmes and intensive Arctic field campaigns have improved our knowledge of glacier-ocean interactions in recent years, especially with respect to fjord/ocean circulation in the marine environment, there are extensive knowledge gaps concerning how glaciers affect marine biogeochemistry and productivity. Following two cross-cutting disciplinary International Arctic Science Committee (IASC) workshops addressing ‘The importance of glaciers for the marine ecosystem’, here we review the state of the art concerning how freshwater discharge affects the marine environment with a specific focus on marine biogeochemistry and biological productivity. Using a series of Arctic case studies (Nuup Kangerlua/Godthåbsfjord, Kongsfjorden, Bowdoin Fjord, Young Sound, and Sermilik Fjord), the interconnected effects of freshwater discharge on fjord-shelf exchange, nutrient availability, the carbonate system, and the microbial foodweb are investigated. Key findings are that whether the effect of glacier discharge on marine primary production is positive, or negative is highly dependent on a combination of factors. These include glacier type (marine- or land-terminating) and the limiting resource for phytoplankton growth in a specific spatiotemporal region (light, macronutrients or micronutrients). Glacier fjords therefore often exhibit distinct discharge-productivity relationships and multiple case-studies must be considered in order to understand the net effects of glacier discharge on Arctic marine ecosystems.

show abstract

Section: Contrasting Fe and No 3 Limited Regions Of The Oceanmentioning

confidence: 85%

Section: Contrasting Fe and No 3 Limited Regions Of The Oceanmentioning

confidence: 99%

Section: Contrasting Fe and No 3 Limited Regions Of The Oceanmentioning

confidence: 99%

See 1 more Smart Citation

Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

Hopwood¹,

Carroll²,

Dunse³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Regardless of the high bioavailability of DOM from glacial discharge, once glacial DOM enters a fjord and is diluted by ocean waters, evidence of its uptake forming a significant component of the microbial food web in the Arctic has yet to be observed. Work from several outlet glacier fjords around Svalbard shows that the stable isotopic C ratio of bacteria does not match that of DOC originating from local glaciers, suggesting that glacially supplied DOC is a minor component of bacterial consumption compared to autochthonous carbon sources (Holding et al, 2017;Paulsen et al, 2018). Curiously, a data synthesis of taxonomic populations for glaciated catchments globally suggests a significant positive effect of glaciers on bacterial populations in glacier fjords but a negative effect in freshwaters and glacier forefields (Cauvy-Fraunié and Dangles, 2019).…”

Section: Organic Matter In Glacial Dischargementioning

confidence: 99%

Review article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

et al. 2020

Self Cite

View full text Add to dashboard Cite

Abstract. Freshwater discharge from glaciers is increasing across the Arctic in response to anthropogenic climate change, which raises questions about the potential downstream effects in the marine environment. Whilst a combination of long-term monitoring programmes and intensive Arctic field campaigns have improved our knowledge of glacier–ocean interactions in recent years, especially with respect to fjord/ocean circulation, there are extensive knowledge gaps concerning how glaciers affect marine biogeochemistry and productivity. Following two cross-cutting disciplinary International Arctic Science Committee (IASC) workshops addressing the importance of glaciers for the marine ecosystem, here we review the state of the art concerning how freshwater discharge affects the marine environment with a specific focus on marine biogeochemistry and biological productivity. Using a series of Arctic case studies (Nuup Kangerlua/Godthåbsfjord, Kongsfjorden, Kangerluarsuup Sermia/Bowdoin Fjord, Young Sound and Sermilik Fjord), the interconnected effects of freshwater discharge on fjord–shelf exchange, nutrient availability, the carbonate system, the carbon cycle and the microbial food web are investigated. Key findings are that whether the effect of glacier discharge on marine primary production is positive or negative is highly dependent on a combination of factors. These include glacier type (marine- or land-terminating), fjord–glacier geometry and the limiting resource(s) for phytoplankton growth in a specific spatio-temporal region (light, macronutrients or micronutrients). Arctic glacier fjords therefore often exhibit distinct discharge–productivity relationships, and multiple case-studies must be considered in order to understand the net effects of glacier discharge on Arctic marine ecosystems.

show abstract

“…As diatoms are more efficiently grazed by Antarctic krill than cryptophytes (Haberman et al 2003), the shift from a diatoms-to a cryptophyte-dominated community may affect food web trophic interactions and, consequently, the ecology of the local marine food web (Moline et al 2004;Ducklow et al 2007). Due to intensification of meltwater conditions in the Southern Ocean, the water column stability has been pointed as an important driver controlling the biomass and composition of phytoplankton communities (Dierssen et al 2002;Moline et al 2004;Mendes et al 2012;Höfer et al 2019). Therefore, studies on phytoplankton and the influence of environmental constraints in species/groups composition are relevant to evaluate ecosystem changes on short-and long-term scales.…”

mentioning

confidence: 99%

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

Costa

Mendes

Tavano

et al. 2020

Limnology & Oceanography

View full text Add to dashboard Cite

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.

show abstract

The role of water column stability and wind mixing in the production/export dynamics of two bays in the Western Antarctic Peninsula

Cited by 53 publications

References 78 publications

Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

Review article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

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

Contact Info

Product

Resources

About