Infaunal density, biomass and bioturbation in the sediments of the Arctic Ocean

Clough, Lisa M.; Ambrose, William G.; Cochran, J. Kirk; Barnes, C; Renaud, Paul E.; Aller, Robert C.

doi:10.1016/s0967-0645(97)00052-0

Cited by 98 publications

(59 citation statements)

References 38 publications

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“…Foraminifera are often neglected in studies on benthic macrofauna, due to the high effort for sorting specimens (Soltwedel 2000;Wollenburg and Kuhnt 2000). Clough et al (1997) conducted one of the few studies recording foraminifera and macrofauna in conjunction with benthic processes in the Arctic. However, foraminiferan contribution to the variability in benthic processes was not statistically analysed, and their contribution to benthic carbon remineralisation was not measured in their study.…”

Section: Discussionmentioning

confidence: 99%

Spring-to-summer changes and regional variability of benthic processes in the western Canadian Arctic

et al. 2011

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Seasonal dynamics in the activity of Arctic shelf benthos have been the subject of few local studies, and the pronounced among-site variability characterizing their results makes it difficult to upscale and generalize their conclusions. In a regional study encompassing five sites at 100-595 m water depth in the southeastern Beaufort Sea, we found that total pigment concentrations in surficial sediments, used as proxies of general food supply to the benthos, rose significantly after the transition from ice-covered conditions in spring (March-June 2008) to open-water conditions in summer (June-August 2008), whereas sediment Chl a concentrations, typical markers of fresh food input, did not. Macrobenthic biomass (including agglutinated foraminifera [500 lm) varied significantly among sites (1.2-6.4 g C m -2 in spring, 1.1-12.6 g C m -2 in summer), whereas a general spring-to-summer increase was not detected. Benthic carbon remineralisation also ranged significantly among sites (11.9-33.2 mg C m -2 day -1 in spring, 11.6-44.4 mg C m -2 day -1 in summer) and did in addition exhibit a general significant increase from spring-to-summer. Multiple regression analysis suggests that in both spring and summer, sediment Chl a concentration is the prime determinant of benthic carbon remineralisation, but other factors have a significant secondary influence, such as foraminiferan biomass (negative in both seasons), water depth (in spring) and infaunal biomass (in summer). Our findings indicate the importance of the combined and dynamic effects of food supply and benthic community patterns on the carbon remineralisation of the polar shelf benthos in seasonally ice-covered seas.

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Section: Discussionmentioning

confidence: 99%

Spring-to-summer changes and regional variability of benthic processes in the western Canadian Arctic

et al. 2011

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“…Bioturbation has been shown to mix surface sediments in these cores to depths of several cm (Clough et al, 1997), and appears responsible for blurred contacts between layers in BC 16, although this is less of an issue in BC 17 .…”

Section: Deglacial Sediment Fluxesmentioning

confidence: 97%

“…Cores from the Eastern Arctic today show rates of bioturbation similar to cores from the Western Arctic (Clough et al, 1997), yet do not show similar intervals of rapid apparent sedimentation rate . Furthermore, few reversals in radiocarbon age are seen at the deglacial in our cores: only one published age model, that of for BC 17, includes a deglacial age reversal, but the coarse fraction weight percent record for that subcore…”

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confidence: 96%

“…Similarly, abundant foraminifera accumulating above glacial sediment might be mixed downward, shifting downcore the apparent sedimentation rate transition inferred from radiocarbon ages. Mixing by bioturbation in the Arctic varies from core to core and is often limited (BC17 is relatively unbioturbated, for example), but may extend to a depth of 2-4 cm (Clough et al, 1997), allowing for the possibility of sediment mixing out of the compressed high-Th glacial section.…”

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confidence: 99%

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Uranium-series radionuclide records of paleoceanographic and sedimentary changes in the Arctic Ocean

Hoffmann¹

2009

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The radionuclides 231 Pa and 230 Th, produced in the water column and removed from the ocean by particle scavenging and burial in sediments, offer a means for paleoceanographers to examine past dynamics of both water column and sedimentary processes. I show for the first time that a state of balance exists between 230 Th production and burial in the Central Arctic basins, based on measured sedimentary 230 Th xs inventories in box cores, establishing this nuclide's utility as a paleoceanographic indicator of sedimentary processes and as a normalization tool. I present the first 230 Th-normalized particle fluxes calculated for the central Arctic: vertical particle fluxes were extremely low during the late glacial, rose during the deglaciation due to particle inputs from shelf inundation, increased productivity and ice-rafted debris, and fell again following the establishment of interglacial conditions. A major event of lateral sediment redistribution, inferred from surplus 230 Th xs inventories, occurred in the Makarov Basin during the deglaciation and may have been due to destabilization of slope and shelf sediments as sea level rose.I present the first high-resolution, radiocarbon-dated downcore records of sedimentary 231 Pa/ 230 Th from the Arctic Ocean. Low ratios indicate that 231 Pa was exported from all sites during the late glacial period, with export decreasing during the deglaciation and Holocene.231 Pa/ 230 Th measurements in cores from three continental slope sites show no evidence for a 231 Pa sink related to boundary scavenging on the continental slopes. Holocene 231 Pa/ 230 Th ratios show a very significant variation by depth, with strong export of 231 Pa at deep sites but little or no export at shallow sites, a result which echoes findings for the South Atlantic and the Pacific. The Arctic thus appears fundamentally similar to other ocean basins in its 231 Pa and 230 Th dynamics, despite its peculiar qualities of sea ice cover, low particle flux, and relatively isolated deep waters.

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“…Therefore, many of the assumptions made for shelf Arctic systems may not be valid for the central Arctic. The few available studies from the central Arctic report extremely low species richness and biomass (Krö ncke 1994(Krö ncke , 1998 for meiofaunal (Vanreusel et al 2000) and macrofaunal taxa (Krö ncke 1994(Krö ncke , 1998Clough et al 1997;Deubel 2000;Bluhm et al 2005;Bluhm, Ambrose et al 2011), as well as a decrease in diversity with increasing water depth (Krö ncke et al 1998). Primary productivity in the central Arctic is limited by light and nutrients.…”

Section: Permanent Ice Cover*high Arcticmentioning

confidence: 99%