The cycling and accumulation of biogenic silica and organic carbon in Antarctic deep-sea and continental margin environments

DeMaster, David J.; Nelson, T.M.; Harden, Stephen L.; Nittrouer, Charles A.

doi:10.1016/s0304-4203(09)90039-1

Cited by 88 publications

(23 citation statements)

References 13 publications

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“…Based on the profiles of 210 Pb and 14 C measured in the sediments collected from Antarctic abyssal and Ž . continental margin regions, DeMaster et al 1991 reported that bioturbation was negligible. For the Southern Ocean site, however, we do not know whether bottom currents had affected the organic matter deposited in the surface sediment and influenced the observed D 14 C profile.…”

Section: Comparison Of D 14 C Signatures In Sediments Of the Two Oceansmentioning

confidence: 99%

Radiocarbon and stable carbon isotope compositions of organic compound classes in sediments from the NE Pacific and Southern Oceans

Wang

Druffel

2001

Marine Chemistry

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AbstractŽ 14 .Ž 13 . Radiocarbon D C abundance and stable carbon isotope d C compositions were measured for total lipid, total Ž . Ž . hydrolyzable amino acids THAA , total carbohydrates TCHO , and acid-insoluble organic fractions separated from Ž . phytoplankton, zooplankton, and sediment cores collected from two abyssal sites, one in the northeast NE Pacific Ocean and one in the Southern Ocean. These results are compared with those obtained for a separate core from the NE Pacific and w Ž . In contrast, sediment from the Southern Ocean had much lower TOC and D 14 C values, which indicated that organic matter was extremely refractory. Sedimentation rates calculated from 14 C ages of TOC for both sites indicate that the differences in the organic composition and D 14 C signatures of organic matter in the sediments likely resulted from the differences in production and deposition of organic matter to the sediment, and the diagenetic stages of sedimentary organic matter in the two oceans. 14 Ž 13 . Unlike D C, stable carbon isotopic d C compositions of TOC in the sediments of the two oceans had similar values, which reflect not only the organic matter input from marine-derived sources but also the nature of degraded, predominately uncharacterized organic fraction in these sediments. The differences in d 13 C values among the compound classes in sediments at both sites can be attributed to the carbon isotopic signatures in original sources during photosynthesis and associated environmental factors. Preferential degradation of organic matter and heterotrophic effects may also play important roles for the observed d 13 C variations and these effects need to be further investigated. q 2001 Elsevier Science B.V. All rights reserved. -C. Wang, E.R.M. Druffelr Marine Chemistry 73 2001 65-81 66

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Section: Comparison Of D 14 C Signatures In Sediments Of the Two Oceansmentioning

confidence: 99%

Radiocarbon and stable carbon isotope compositions of organic compound classes in sediments from the NE Pacific and Southern Oceans

Wang

Druffel

2001

Marine Chemistry

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“…for AESOPS see: Moore et al, 1999;Abbott et al, 2000;Barth et al, 2001). High silica fluxes to the sediments below the PFZ are found to be correlated to the blooms of large diatoms which sink to the deep sea forming the sedimentary opal belt surrounding Antarctica (Demaster et al, 1991;Pondaven et al, 2000). North of the PFZ in the Subantarctic Zone (SAZ), smaller nano-and pico-plankton dominate the phytoplankton biomass (Griffiths et al, 1999;Kopczynska et al, 2001), and shifts to lower export:production ratios might be expected.…”

Section: Introductionmentioning

confidence: 99%

The effect of marginal ice-edge dynamics on production and export in the Southern Ocean along 170°W

Buesseler

Barber

Dickson

et al. 2003

Deep Sea Research Part II: Topical Studies in Oceanography

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We present a synthesis of the rates of gross, new, net and primary production along with particulate organic carbon (POC) flux at 100 m from four cruises along 1701W in the Southern Ocean. Concurrent satellite pigment data, a primary productivity model, and a nitrate mass balance are used to extrapolate daily production estimates in space and time to seasonal and annual rates. From this analysis, we gain a better understanding of the timing, magnitude and impact of the phytoplankton blooms in this region. One of the dominant features with respect to plankton biomass is the association of high chlorophyll levels with the retreat of the sea ice which begins in October just south of the Polar Front. Our primary production model and satellite pigment data suggest higher production and flux levels characterize the marginal ice zone than previous estimates. Elevated rates of new production in ice impacted regions are restricted to relatively short periods following retreat of the ice edge. Export is found to lag the onset of production by up to 1 month. The ratio of POC flux at 100 m to primary production when averaged over the entire season is quite high, increasing from 15% to 25% in the Subantarctic zones to 35-40% near the Polar Front and as high as 50-65% in the southernmost stations, just north of the Ross Sea gyre. Comparisons of phytoplankton community structure and Fe stress indicators suggest that blooms at the Polar Front are initially dominated by large centric diatoms, but are replaced by smaller pennate diatom and non-diatom species as Fe levels decrease. Further south, where Fe levels are never as high and large diatoms are not found, we still observe relatively high biomass and elevated production rates and POC fluxes during the short growing season. r

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“…However we lack a firm quantitative, observational basis to serve as a foundation for these statements, and the models from which they are derived. Marginal ice zones (MIZ) within the 'E-mail: duck@vims.edu Q Inter- Research 1999 Southern Ocean are regimes characterized by large seasonal pulses of primary productivity and vertical fluxes to the sediments (Smith & Nelson 1985, DeMaster et al 1991. The significance of biogeochemical processes in these MIZ regimes is not established, partly because of a paucity of modern biogeochemical studies on the carbon cycle, and partly because the role of ocean margin systems generally is still poorly understood as well as controversial (Mantoura et al 1991, Smith & Hollibaugh 1993.…”

Section: Introductionmentioning

confidence: 99%

Bacterial growth in experimental plankton assemblages and seawater cultures from the Phaeocystis antarctica bloom in the Ross Sea, Antarctica

Ducklow¹,

Carlson²,

Smith³

1999

Aquat. Microb. Ecol.

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A series of seawater culture experiments was carried out during the Phaeocystis antarctica bloom in the Ross Sea polynya (76S0S, 180°W; November to December 1994 and December 1995 to January 1996) to examine bacterioplankton growth and derive empirical factors for estimating bacterial production rates. Bacterial growth was exponential over 3 to 10 d in all experiments, at rates of ca 0.1 to 0.7 d-', even in persistently cold waters (-2 to + 1°C) Growth rates were lower in the early part of the bloom (early to mid-November) and highest during the period of peak primary productivity (2 to 4 g C m-' d-' in late November through December). Apparent lag phases in the growth curves lasting 1 to 7 d could be accounted for mathematically by subpopulations in the bacterial assemblages growing exponentially at different rates, with no need to invoke inactive, nondividing or nonviable populat i o n~. Lags were absent dunng the period of peak primary production, suggesting adaptation of the bacteria to ambient DOM Growth was not stimulated by small temperature increases (A+2 to 4"C), and was not balanced by removal processes in untreated 'whole' water samples. Growth rates were broadly s~rmlar to other directly observed bacterial growth rates in the Antarctic and did not appear to Mfer from rates in warmer waters. Conversion factors for thymidine and leuclne averaged 8 and 0.8 X 10'' cells mol-l, respectively, not dissimilar to estimates from temperate waters. These findings suggest that bacteria were growing actively in 0 to -Z°C waters under rich bloom conditions, and lend strong support to the hypothesis that bacterioplankton metabolism controls DOC accumulation in Antarctic waters, at least at the low rates of DOM supply we infer from field and experimental observations. Bactenoplankton responded within 10 to 20 d to the evolving P. antarctica bloom and did not appear to behave substantially differently from lower latitude bloom systems.

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The cycling and accumulation of biogenic silica and organic carbon in Antarctic deep-sea and continental margin environments

Cited by 88 publications

References 13 publications

Radiocarbon and stable carbon isotope compositions of organic compound classes in sediments from the NE Pacific and Southern Oceans

Radiocarbon and stable carbon isotope compositions of organic compound classes in sediments from the NE Pacific and Southern Oceans

The effect of marginal ice-edge dynamics on production and export in the Southern Ocean along 170°W

Bacterial growth in experimental plankton assemblages and seawater cultures from the Phaeocystis antarctica bloom in the Ross Sea, Antarctica

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