Chlorophyll <i>a</i> in Antarctic sea ice from historical ice core data

Meiners, Klaus M.; Vancoppenolle, Martin; Thanassekos, Stéphane; Dieckmann, Gerhard; Thomas, David N.; Tison, Jean-Louis; Arrigo, Kevin R.; Garrison, David L.; McMinn, Andrew; Lannuzel, Delphine; Merwe, Pier van der; Swadling, KM; Smith, Walker O; Melnikov, I. A.; Raymond, Ben

doi:10.1029/2012gl053478

Cited by 100 publications

(118 citation statements)

References 26 publications

(41 reference statements)

Supporting

Mentioning

108

Contrasting

Unclassified

Order By: Relevance

“…Concentrations of chl a within the sea ice and water column in the pack-ice zone found during our study were consistent with previous data from the Weddell Sea and other regions of the Southern Ocean in winter (western Antarctic Peninsula region, northwestern Weddell Sea, Lazarev Sea, East Antarctica) 8,[13][14][15][23][24][25][26] . Previous larval krill winter studies in the western Antarctic Peninsula region demonstrate significantly different growth rates between years, at the same time and location, due to variable chl a concentration in the water column.…”

Section: Nature Ecology and Evolutionsupporting

confidence: 92%

“…We investigated feeding activity and growth rates of Antarctic krill larvae in the Scotia and northern Weddell Sea (14 August to 16 October 2013, Punta Arenas-Cape Town) in three different zones: (1) the persistently ice-free, open water (OW) region off South Georgia, (2) the marginal ice zone (MIZ) and (3) the pack-ice zone (PIZ). Food supply in terms of chl a and particulate organic matter were measured in the water column and within sea ice as proxies for the autotrophic and heterotrophic/detrital biomass, respectively 14,26,39 . At all locations, larval krill sampling was performed with a number of different of net and pump systems.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The winter pack-ice zone provides a sheltered but food-poor habitat for larval Antarctic krill

et al. 2017

View full text Add to dashboard Cite

A ntarctic krill Euphausia superba, a key species in Southern Ocean food webs 1 , plays a central role in ecosystem processes and community dynamics of apex predators, and is the target of a commercial fishery 2 . Krill spawn in late spring and their larvae develop during summer, autumn and under the ice in winter to emerge as juveniles in the following spring. The newly spawned eggs sink from the surface to up to 1,000 m depth where they hatch and the developing larvae actively swim upwards to feed in the upper water column 1 . Larval Antarctic krill have low lipid reserves, which are insufficient to support long periods of starvation. Therefore, winter, when primary production is minimal, is assumed to be a critical bottleneck for larval krill development and hence recruitment to the adult population 3,4 . Present hypotheses suggest that high algal biomass in winter sea ice enhances larval krill winter-feeding conditions and growth [5][6][7][8] . This implies that larvae have access to this high algal biomass within the sea ice. However, recent observations 9,10 indicate that the linkage between sea ice and krill recruitment success is not as direct as has been suggested. The timing of ice-edge advance and annual ice-season duration is highly variable, and does not necessarily show a clear link to krill recruitment in the following year ( Supplementary Figs. 1 and 2). Along the Antarctic Peninsula, adult krill have a five to six year population cycle with oscillations in biomass exceeding an order of magnitude 9 . According to bioenergetics models, part of the variability is due to interannual variation in reproductive output 11 as well as autumn blooms that may govern the possible overwinter survival rate of larvae 11,12 . In the Bransfield Strait, three krill winter surveys have shown that krill abundance is an order of magnitude higher than in summer, regardless of concurrent sea-ice conditions 10 A dominant Antarctic ecological paradigm suggests that winter sea ice is generally the main feeding ground for krill larvae. Observations from our winter cruise to the southwest Atlantic sector of the Southern Ocean contradict this view and present the first evidence that the pack-ice zone is a food-poor habitat for larval development. In contrast, the more open marginal ice zone provides a more favourable food environment for high larval krill growth rates. We found that complex under-ice habitats are, however, vital for larval krill when water column productivity is limited by light, by providing structures that offer protection from predators and to collect organic material released from the ice. The larvae feed on this sparse ice-associated food during the day. After sunset, they migrate into the water below the ice (upper 20 m) and drift away from the ice areas where they have previously fed. Model analyses indicate that this behaviour increases both food uptake in a patchy food environment and the likelihood of overwinter transport to areas where feeding conditions are more favourable in spring.

show abstract

Section: Nature Ecology and Evolutionsupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

The winter pack-ice zone provides a sheltered but food-poor habitat for larval Antarctic krill

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Our second model includes Chl a, and provides a better fit than the physical model. Airborne or satellite remote sensing cannot determine sea ice Chl a (because of the presence of overlying snow and ice depth), but this model could be used in association with under-ice spatial Chl a data, or derived from large-scale relationships between Chl a, ice thickness, and seasonality (45,49).…”

Section: Discussionmentioning

confidence: 99%

“…4A) predicts sea ice dCHO concentration on the basis of ice thickness, vertical position in the ice core, and core salinity. Ice thickness has been found to be key in determining sea ice Chl a in Antarctic pack ice (45). Approaches are being developed to assess ice thickness based on remote-sensing technologies (46,47).…”

Section: Discussionmentioning

confidence: 99%

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

Underwood

Aslam

Michel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Sea ice can contain high concentrations of dissolved organic carbon (DOC), much of which is carbohydrate-rich extracellular polymeric substances (EPS) produced by microalgae and bacteria inhabiting the ice. Here we report the concentrations of dissolved carbohydrates (dCHO) and dissolved EPS (dEPS) in relation to algal standing stock [estimated by chlorophyll (Chl) a concentrations] in sea ice from six locations in the Southern and Arctic Oceans. Concentrations varied substantially within and between sampling sites, reflecting local ice conditions and biological content. However, combining all data revealed robust statistical relationships between dCHO concentrations and the concentrations of different dEPS fractions, Chl a, and DOC. These relationships were true for whole ice cores, bottom ice (biomass rich) sections, and colder surface ice. The distribution of dEPS was strongly correlated to algal biomass, with the highest concentrations of both dEPS and non-EPS carbohydrates in the bottom horizons of the ice. Complex EPS was more prevalent in colder surface sea ice horizons. Predictive models (validated against independent data) were derived to enable the estimation of dCHO concentrations from data on ice thickness, salinity, and vertical position in core. When Chl a data were included a higher level of prediction was obtained. The consistent patterns reflected in these relationships provide a strong basis for including estimates of regional and seasonal carbohydrate and dEPS carbon budgets in coupled physical-biogeochemical models, across different types of sea ice from both polar regions. S ea ice covers extensive regions of the Arctic and SouthernOceans, as well as some subpolar seas, and exhibits major annual, interannual, and long-term climate-related variability in age, thickness, and structure (1-3). Sea ice is not an inert physical barrier to air-ocean exchange (4), and both microbial activity and physico-chemical reactions within the ice contribute to regional-scale biogeochemical processes at the air-ocean surface interface (5).Sea ice provides a range of habitats for diverse biological assemblages that are characterized by high standing stocks of microalgae and bacteria (6). These microorganisms produce large quantities of dissolved organic carbon (DOC), often in the form of carbohydrate-rich extracellular polymeric substances (EPS) (7). Microbial EPS exist in a dynamic equilibrium from dissolved polysaccharides (dEPS <0.2 μm) to complex particulate EPS that can form gels on the millimeter to centimeter scale (8). Here we focus on the biologically relevant dissolved carbohydrates (dCHO) that constitute a substantial fraction of the DOC in sea ice (9-13) (Fig. 1). dCHO are concentrated from sea ice DOC by dialysis (>8 kDa), with subsequent treatment allowing the definition of four subcomponents of the total dCHO pool: (i) dissolved uronic acids (dUA), produced by ice diatoms and ice bacteria (14-16), that confer strong cross-linkages between polymer chains (8), forming low solubility EPS complexes w...

show abstract

“…Upper level ecosystems are mentioned for the Arctic almost solely anecdotally, for example in the monograph by Melnikov [64]. A working hypothesis is that freeboard and infiltration layers better studied in the Southern Hemisphere [42,66] occur only peripherally and occasionally in the Arctic -although this may be changing as northern ice becomes more seasonal.…”

Section: Observational Datamentioning

confidence: 99%

Strategies for the Simulation of Sea Ice Organic Chemistry: Arctic Tests and Development

Elliott¹,

Jeffery²,

Hunke³

et al. 2017

Preprint

View full text Add to dashboard Cite

Abstract:A numerical mechanism connecting ice algal ecodynamics with the buildup of organic macromolecules is tested within modeled pan-Arctic brine channels. The simulations take place offline in a reduced representation of sea ice geochemistry. Physical driver quantities derive from the global sea ice code CICE, including snow cover, thickness and internal temperature. The framework is averaged over ten boreal biogeographic zones. Computed nutrient-light-salt limited algal growth supports grazing, mortality and carbon flow. Vertical transport is diffusive but responds to pore structure. Simulated bottom layer chlorophyll maxima are reasonable, though delayed by about a month relative to observations due to uncertainties in snow variability. Upper level biota arise intermittently during flooding events. Macromolecular concentrations are tracked as proxy proteins, polysaccharides, lipids and refractory humics. The fresh biopolymers undergo succession and removal by bacteria. Baseline organics enter solely through cell disruption, so that the internal carbon content is initially biased low. By including exudation, agreement with dissolved organic or individual biopolymer data is achieved given strong release coupled to light intensity. Detrital carbon then reaches hundreds of micromolar, sufficient to support structural changes to the ice matrix.

show abstract

Chlorophyll a in Antarctic sea ice from historical ice core data

Cited by 100 publications

References 26 publications

The winter pack-ice zone provides a sheltered but food-poor habitat for larval Antarctic krill

The winter pack-ice zone provides a sheltered but food-poor habitat for larval Antarctic krill

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

Strategies for the Simulation of Sea Ice Organic Chemistry: Arctic Tests and Development

Contact Info

Product

Resources

About