Regional Changes in Icescape Impact Shelf Circulation and Basal Melting

Cougnon, Eva A.; Rintoul, Stephen R.; Legrésy, B.; Williams, Guy D.; Fraser, Alexander; Hunter, John

doi:10.1002/2017gl074943

Cited by 27 publications

(41 citation statements)

References 59 publications

(98 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The postulated more favorable environment on the Mertz Bank might continue to persist for some time until the MGT regrows the ice tongue. Further, oceanographic models from after the calving indicate an increase in basal melting of the MGT due to warmer, faster moving waters from the east after grounded tabular iceberg relocation and the MGT calving (Cougnon et al, 2017) which may slow the regrowth of the MGT.…”

Section: Discussionmentioning

confidence: 99%

“…The missing data at the previous location of the MGT stems from a landmask-artifact in the NASA-data. Panels (D-F) represent the speed of fluctuating currents (tidal currents) at the bottom layer of the regional ocean model used for this study (Cougnon et al, 2017). Panels (G-I) show the number of particles moving horizontally along the seafloor before their permanent sedimentation (on log-scale).…”

Section: Discussionmentioning

confidence: 99%

“…Since the calving of the MGT, the Mertz Polynya has decreased significantly in size (Tamura et al, 2016), changing ocean circulation Cougnon et al, 2017;Kusahara et al, 2017) and increasing sea-ice concentrations (Tamura et al, 2012). The iceberg B09B grounded on the SouthEastern flank of the Adélie Bank shortly after the collision, and a new polynya has formed on its leeward side .…”

Section: Study Areamentioning

confidence: 99%

“…The calving of the Mertz Glacier Tongue (MGT) in 2010 (Young et al, 2010) has resulted in profound environmental changes in the region, such as increased sea-ice concentrations (Campagne et al, 2015), and changes in ocean currents along the shelf as suggested by observations and modeling studies (Cougnon et al, 2017;Kusahara et al, 2017). These environmental changes have consequences for the dynamics and distribution of primary production (Shadwick et al, 2013), the abundance of top-predators (Wilson et al, 2016), and has been observed to influence the community structure of shallow-water benthos (Clark et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…In our modeling, we apply a recently developed FAM on two 5-year climatologies of remotely sensed surface chlorophyll-a for the period before and after the glacier calving, and use ocean current velocities from a purpose-built oceanographic model (Cougnon et al, 2017) (more details can be found in the section Materials and Methods). We then (ii) map the distribution of benthic suspension feeder abundances before the glacier calving, using faunal abundances derived from underwater camera images and environmental predictor variables.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Mapping Antarctic Suspension Feeder Abundances and Seafloor Food-Availability, and Modeling Their Change After a Major Glacier Calving

et al. 2018

View full text Add to dashboard Cite

Seafloor communities are a critical part of the unique and diverse Antarctic marine life. Processes at the ocean-surface can strongly influence the diversity and abundance of these communities, even when they live at hundreds of meters water depth. However, even though we understand the importance of this link, there are so far no quantitative spatial predictions on how seafloor communities will respond to changing conditions at the ocean surface. Here, we map patterns in abundance of important habitat-forming suspension feeders on the seafloor in East Antarctica, and predict how these patterns change after a major disturbance in the icescape, caused by the calving of the Mertz Glacier Tongue. We use a purpose-built ocean model for the time-period before and after the calving of the Mertz-Glacier Tongue in 2010, data from satellites and a validated food-availability model to estimate changes in horizontal flux of food since the glacier calving. We then predict the post-calving distribution of suspension feeder abundances using the established relationships with the environmental variables, and changes in horizontal flux of food. Our resulting maps indicate strong increases in suspension feeder abundances close to the glacier calving site, fueled by increased food supply, while the remainder of the region maintains similar suspension feeder abundances despite a slight decrease in total food supply. The oceanographic setting of the entire region changes, with a shorter ice-free season, altered seafloor currents and changes in food-availability. Our study provides important insight into the flow-on effects of a changing icescape on seafloor habitat and fauna in polar environments. Understanding these connections is important in the context of current and future effects of climate change, and the mapped predictions of the seafloor fauna as presented for the study region can be used as a decision-tool for planning potential marine protected areas, and for focusing future sampling and monitoring initiatives.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mapping Antarctic Suspension Feeder Abundances and Seafloor Food-Availability, and Modeling Their Change After a Major Glacier Calving

et al. 2018

View full text Add to dashboard Cite

show abstract

Rapid volume reduction in Antarctic Bottom Water off the Adélie/George V Land coast observed by deep floats

Kobayashi

2018

Deep Sea Research Part I: Oceanographic Research Papers

View full text Add to dashboard Cite

Influence of ocean tides and ice shelves on ocean–ice interactions and dense shelf water formation in the D’Urville Sea, Antarctica

et al. 2021

View full text Add to dashboard Cite

The D'Urville Sea, East Antarctica, is a major source of Dense Shelf Water (DSW), a precursor of Antarctic Bottom Water (AABW). AABW is a key water mass involved in the worldwide ocean circulation and longterm climate variability. The properties of AABW in global climate models suffer from several biases, making climate projections uncertain. These models are potentially omitting or misrepresenting important mechanisms involved in the formation of DSW, such as tides and ocean-ice shelf interactions. Recent studies pointed out that tides and ice shelves significantly influence the coastal seas of Antarctica, where AABW originates from. Yet, the implications of these two processes in the formation and evolution of DSW are poorly understood, in particular in the D'Urville Sea. Using a series of NEMO-LIM numerical simulations, we assess the sensitivity of dense water formation in the D'Urville Sea to the representation of tides and ocean-ice shelf interactions during the years 2010-2015. We show that the ice shelves off Adélie Land are highly sensitive to tidal forcing, with a significant basal melt increase in the presence of tides. Ice shelf basal melt freshens and cools the ocean over significant portions of the coastal seas at the depth of the ice shelf draft. An opposite warming and increase in salinity are found in the upper layers. The influence of ice shelf basal melt on the ocean is largely increased in the presence of tides. However, the production of sea ice is found to be mostly unaffected by these two processes. Water mass transport out of polynyas and ice shelf cavities are then investigated, together with their sensitivity to tides and ocean-ice shelf interactions. Ice shelf basal melt impacts the volume of dense waters in two ways: (1) Dense Shelf Water and Modified Shelf Water are consumed to form water masses of intermediate density inside the ice shelf cavities, and (2) the freshening of the ocean subsurface makes its transformation into dense water by sea ice formation more difficult. These results suggest that ice shelf basal melt variability can explain part of the observed changes of dense water properties, and may also affect the production of dense water in a future climate.

show abstract

Regional Changes in Icescape Impact Shelf Circulation and Basal Melting

Cited by 27 publications

References 59 publications

Mapping Antarctic Suspension Feeder Abundances and Seafloor Food-Availability, and Modeling Their Change After a Major Glacier Calving

Mapping Antarctic Suspension Feeder Abundances and Seafloor Food-Availability, and Modeling Their Change After a Major Glacier Calving

Rapid volume reduction in Antarctic Bottom Water off the Adélie/George V Land coast observed by deep floats

Influence of ocean tides and ice shelves on ocean–ice interactions and dense shelf water formation in the D’Urville Sea, Antarctica

Contact Info

Product

Resources

About