Antarctic sympagic meiofauna in winter: Comparing diversity, abundance and biomass between perennially and seasonally ice-covered regions

Kramer, Maike; Swadling, Kerrie M.; Meiners, Klaus M.; Kiko, Rainer; Scheltz, Annette; Nicolaus, Marcel; Werner, Iris

doi:10.1016/j.dsr2.2010.10.029

Cited by 221 publications

(24 citation statements)

References 50 publications

(75 reference statements)

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“…For example, postwinter/early spring communities have been observed to comprise dinoflagellates, ciliates, cercozoans, Stramenopiles, Viridiplantae, haptophytes, and metazoans, or a dinoflagellate-dominated community, or a diatom-dominated community that developed after sea ice breakup (Piquet et al, 2008). Furthermore, at the end of winter, phototrophs may be essentially absent from sea ice, having been removed by extensive over-winter grazing (Bachy et al, 2011), although spatial heterogeneity can result in significantly different postwinter communities (Kramer et al, 2011). Evidence from Arctic sea ice suggests that communities inhabiting the ice/water interface are more similar to seawater communities than those entrained higher in the ice matrix, isolated from seawater intrusions (Bachy et al, 2011).…”

Section: Virioplankton: Crucial Influence and Much To Be Learnedmentioning

confidence: 99%

Key microbial drivers in Antarctic aquatic environments

et al. 2013

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Antarctica is arguably the world's most important continent for influencing the Earth's climate and ocean ecosystem function. The unique physico-chemical properties of the Southern Ocean enable high levels of microbial primary production to occur. This not only forms the base of a significant fraction of the global oceanic food web, but leads to the sequestration of anthropogenic CO2 and its transport to marine sediments, thereby removing it from the atmosphere; the Southern Ocean accounts for ~ 30% of global ocean uptake of CO2 despite representing ~ 10% of the total surface area of the global ocean. The Antarctic continent itself harbors some liquid water, including a remarkably diverse range of surface and subglacial lakes. Being one of the remaining natural frontiers, Antarctica delivers the paradox of needing to be protected from disturbance while requiring scientific endeavor to discover what is indigenous and learn how best to protect it. Moreover, like many natural environments on Earth, in Antarctica, microorganisms dominate the genetic pool and biomass of the colonizable niches and play the key roles in maintaining proper ecosystem function. This review puts into perspective insight that has been and can be gained about Antarctica's aquatic microbiota using molecular biology, and in particular, metagenomic approaches.

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Section: Virioplankton: Crucial Influence and Much To Be Learnedmentioning

confidence: 99%

Key microbial drivers in Antarctic aquatic environments

et al. 2013

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“…Sea ice is active in feedback mechanisms between ice, the atmosphere, and the ocean and thus key in the climate system (e.g., Massom and Stammerjohn 2010); it also generates brines that form bottom waters (e.g., Smith et al 2010), participates in biogeochemical cycling, and exerts control on diverse biological processes throughout the water column and on the seafloor in polar seas (e.g., Dieckmann and Hellmer 2009;Atkins and Dunbar 2009;Kramer et al 2011). Relative to seasonal sea ice, multiyear sea ice minimizes ocean-atmosphere exchange (e.g., Hillenbrand and Cortese 2006), and reduces productivity, thus adversely affecting planktic, nektic, and benthic organisms (e.g., Lohrer et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Sediments Beneath Multi-Year Sea Ice: Delivery By Deltaic and Eolian Processes

Miller¹,

Fan²,

Bowser³

2015

Journal of Sedimentary Research

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Little is known about land-to-sea sediment transport and deposition in polar regimes with multi-year sea ice such as at the mouth of the Taylor Valley, one of the Dry Valleys in Antarctica. This study integrates textural analysis of 574 coastal subaerial and nearshore submarine sediment samples with data from sediment traps and with published grain-size analyses of offshore sea-ice surface and submarine sediments to reconstruct transport and depositional processes from the shoreline to , 8 km offshore.Sediment, primarily sand sized, is transferred into the marine environment via two processes: 1) erosion, transport, and deposition of till by ephemeral meltwater streams that deliver sediment to the subaqueous part of the delta built over the last , 7,500 years, and 2) onshore to sea-ice sediment transport by wind during rare but powerful foehn wind events. Because the distributaries flow into quiet water beneath the sea ice, most of their load is dropped close to shore, but a small amount of finegrained sediment, mostly silt, is carried kilometers offshore, probably by low-density, low-salinity plumes.Wind deposits sediment on the sea ice with median grain size decreasing from medium to fine sand within 1.5 km of the shoreline; even offshore sea-ice sediment contains very little silt and almost no clay. Nearshore the sea-ice sediment is coarser than that on the underlying seafloor, but in a few kilometers offshore the median grain sizes of the seafloor and sea-ice sediments are similar; this reflects a mixture of sea-ice-rafted eolian sediment and fine-grained delta-derived sediment transported beneath the sea ice.This system is unusual in the relative effectiveness of the transport systems. The feeble distributaries deposit their sediment load immediately upon entering the quiet water, and only a minor amount of silt and clay is carried seaward under the ice. In contrast, winds deposit coarser sediment on the nearshore sea ice and carry fine sand . 7 km offshore, although the amount and grain size of sediment is attenuated within 1.5 km of shore. Melting of the sea ice drops sediment onto the seafloor, where it mixes with the delta-derived silt and clay. Similar combinations of eolian and fluvial transport processes may have operated in polar regimes dominated by multi-year sea ice in the past. Understanding of the modern processes in Explorers Cove may aid recognition of ancient sediments deposited under multi-year sea ice, as well as help predict future changes in processes around Antarctica as the distribution of multi-year sea ice shifts in response to climate change.

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“…, 2010) but their identification requires the establishment of a sedimentary context of deposition under permanent or near‐permanent sea ice. Recent recognition of multi‐year sea ice as a habitat for relatively high diversity meiofaunal communities (Kramer et al. , 2011) and multi‐year fast ice as a determinant of the behaviour of nearby glacial tongues (Massom et al.…”

Section: Introductionmentioning

confidence: 99%

“…Polynas were likely islands of high productivity and perhaps served as biological refugia during periods of ice sheet advance as during the Last Glacial Maximum (LGM; Smith et al, 2010) but their identification requires the establishment of a sedimentary context of deposition under permanent or near-permanent sea ice. Recent recognition of multi-year sea ice as a habitat for relatively high diversity meiofaunal communities (Kramer et al, 2011) and multi-year fast ice as a determinant of the behaviour of nearby glacial tongues (Massom et al, 2010) adds to the importance of recognizing multi-year sea ice in the sedimentary record for better understanding of ice streaming and of palaeo-ice community dynamics, as well as of palaeoclimate and ocean-atmosphere interactions.…”

Section: Introductionmentioning

confidence: 99%

Depositional processes beneath coastal multi‐year sea ice

Murray¹,

Miller²,

Bowser

2012

Sedimentology

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The extent of multi‐year sea ice impacts climate processes worldwide, such as ocean–atmosphere carbon dioxide exchange and deep ocean current formation. Reconstructing these processes in the past, and assessing the distribution of ecologically and climatically significant features, such as polynas, requires recognition of sediments deposited under multi‐year sea ice, but little is known about their characteristics. Textural analysis of subaerial and sea floor sediment in Explorers Cove, McMurdo Sound, at the mouth of Taylor Valley, Antarctica, augmented with observations of sedimentary structures and faunal components, elucidates how sediment is transported to the sea floor and allows characterization of the deposits. Comparison of grain‐size characteristics of subaerial (moraine, delta and sea‐ice surface) sediment and sea floor sediment from short cores taken at depths of 7 to 25 m indicates that the likely source of the moderately to poorly sorted sea floor sand is deltaic sediment; small glacial meltwater streams have built deltas since Taylor Valley became ice‐free ca 7000 years ago. Windblown sediment accumulating on the multi‐year sea ice close to the coast typically is coarser grained than sediment on the sea floor; this suggests that the transport of sediment through the ice to the sea floor is not the predominant mode of sediment transfer. However, supra‐sea‐ice sediment does move to the sea floor through local fractures. The rate of sedimentation under multi‐year sea ice is low because of limited stream flow and biogenic sedimentation; the ice cover inhibits primary productivity and dampens waves, precluding physical re‐suspension. The upper centimetres of sea floor sediment are churned by epifaunal scallops and brittle stars that leave no telltale biogenic structures and whose calcite ossicles and shells may be poorly preserved. The resulting deposits under multi‐year sea ice are poorly sorted, massive sand that provides little evidence of the bioturbators that have masked the indicators of the original physical depositional processes.

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Antarctic sympagic meiofauna in winter: Comparing diversity, abundance and biomass between perennially and seasonally ice-covered regions

Cited by 221 publications

References 50 publications

Key microbial drivers in Antarctic aquatic environments

Key microbial drivers in Antarctic aquatic environments

Sediments Beneath Multi-Year Sea Ice: Delivery By Deltaic and Eolian Processes

Depositional processes beneath coastal multi‐year sea ice

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