Calcareous nannoplankton biocoenosis : sediment trap studies in the equatorial Atlantic, central Pacific, and Panama Basin

Steinmetz, John C.

doi:10.1575/1912/406

Cited by 24 publications

(13 citation statements)

References 39 publications

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“…Coccoliths are shed continuously, however, when the cell dies or lyses, large concentrations of coccoliths are detached and the surrounding water turns a characteristic milky white and it is during this period the bloom can be easily observed by satellite imagery. A vertical £ux then follows as coccoliths sink to the seabed (Steinmetz, 1991;Ziveri et al, 2000). Consequently, high re£ectance areas of any bloom are likely to be comprised of dead or dying E. huxleyi cells and the aim of this study was to determine if viruses are the cause of death.…”

Section: Discussionmentioning

confidence: 99%

Isolation of viruses responsible for the demise of an Emiliania huxleyi bloom in the English Channel

et al. 2002

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This study used analytical £ow cytometry (AFC) to monitor the abundance of phytoplankton, coccoliths, bacteria and viruses in a transect that crossed a high re£ectance area in the western English Channel. The high re£ectance area, observed by satellite, was caused by the demise of an Emiliania huxleyi bloom. Water samples were collected from depth pro¢les at four stations, one station outside and three stations inside the high re£ectance area. Plots of transect data revealed very obvious di¡erences between Station 1, outside, and Stations 2^4, inside the high re£ectance area. Inside, concentrations of viruses were higher; E. huxleyi cells were lower; coccoliths were higher; bacteria were higher and virus:bacteria ratio was lower than at Station 1, outside the high re£ectance area. This data can simply be interpreted as virusinduced lysis of E. huxleyi cells in the bloom causing large concentrations of coccoliths to detach, resulting in the high re£ectance observed by satellite imagery. This interpretation was supported by the isolation of two viruses, EhV84 and EhV86, from the high re£ectance area that lysed cultures of E. huxleyi host strain CCMP1516. Basic characterization revealed that they were lytic viruses approximately 170 nm^190 nm in diameter with an icosahedral symmetry. Taken together, transect and isolation data suggest that viruses were the major contributor to the demise of the E. huxleyi population in the high re£ectance area. Close coupling between microalgae, bacteria and viruses contributed to a large organic carbon input. Consequent cycling in£uenced the succession of an E. huxleyi-dominated population to a more characteristic mixed summer phytoplankton community.

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Section: Discussionmentioning

confidence: 99%

Isolation of viruses responsible for the demise of an Emiliania huxleyi bloom in the English Channel

et al. 2002

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“…group is less known. H. hyalina and/or H. pavimentum are rare to occasional in the equatorial tropical and subtropical zone of the Pacific and in the equatorial Atlantic (Okada and McIntyre, 1977;Steinmetz, 1991). The parallel increase in S1 of Helicosphaera spp.…”

Section: Paleoecological Reconstruction Of the S1 Interval Based On Mmentioning

confidence: 98%

Phyto_ and zooplankton paleofluxes during the deposition of sapropel S1 (eastern Mediterranean): Biogenic carbonate preservation and paleoecological implications

Principato

Crudeli

Ziveri

et al. 2006

Palaeogeography, Palaeoclimatology, Palaeoecology

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(M.S. Principato). Abstract The relative and absolute abundances and accumulation rates of foraminifera and calcareous nannofossils were quantified in a box core containing sapropel S1 from the Florence Rise area (SE of Cyprus; 2302 m water depth). The main objective of this study was to reconstruct in detail variations in paleoecological conditions of water masses during the deposition of this sapropel. In particular, we qualitatively evaluated the importance of carbonate dissolution on planktonic assemblages to better interpret the abundance profiles obtained from the two investigated taxa. Selective carbonate corrosion in the core is shown by (1) the decrease in shell mass weight of selected species of planktonic foraminifera, (2) the decrease in accumulation rate of dissolution-susceptible holococcoliths and coccolith species, and (3) the absence of pteropods. However, the presence of other relatively dissolution-susceptible coccolith species throughout all of the S1 interval suggests moderate dissolution. Florisphaera profunda shows a marked increase in paleofluxes within the sapropel coupled with a decrease in the accumulation rate of the upper-middle photic zone coccoliths, suggesting an ecological depth-separation of the water column, probably characterised by higher nutrient availability at depth and nutrient-depleted surface waters between ~ 10 and 6.5 kyr BP. In the same interval Turborotalita quinqueloba and Globigerina bulloides, two foraminiferal species frequently occurring during periods of high fertility, increase in relative abundance. The maximum increase in relative abundance of Globigerinoides ruber (var. alba and rosea) marks the climatic optimum phase and the maximum stratification in surface water that occurred at the beginning of sapropel S1 deposition when the bottom waters were anoxic. An important change in foraminiferal assemblages occurs at ~8 kyr BP and corresponds with a negative shift in CaCO 3 , Ba and C org contents. This short interval marks the establishment of relatively less anoxic conditions in the bottom water, introducing the last phase of sapropel formation. Palaeogeography, Palaeoclimatology, Palaeoecology 235 (2006) 8-27 www.elsevier.com/locate/palaeo After ~ 6.5 kyr BP, a progressive re-establishment of normal oceanographic conditions occurred before the real end of the sapropel S1. This transition is well recorded by the reoccurrence and major accumulation rate of the mixing indicator foraminiferal species Globorotalia inflata and by the gradual decrease in abundance of F. profunda. D

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“…Our fluxes correspond to 4.93 Â 10 8 to 1.34 Â 10 10 liths m À2 d À1 . Current coccolith fluxes in the mid-equatorial Atlantic measure from 6.2 Â 10 7 to 7.8 Â 10 8 liths m À2 d À1 in the mid-equatorial Atlantic (Steinmetz, 1991). Haidar and Thierstein (2001) measured an average flux of 1.4 Â 10 9 liths m À2 d À1 around Bermuda.…”

Section: Coccolith Relative Abundance Datamentioning

confidence: 98%

Coccolithophores as palaeoecological indicators for shifts of the ITCZ in the Cariaco Basin during the late Quaternary

Mertens

Lynn

Aycard

et al. 2008

J Quaternary Science

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Mertens, K. N. J. M., Lynn, M., Aycard, M., Lin, H.-L. and Louwye, S. 2009. Coccolithophores as palaeoecological indicators for shifts of the ITCZ in the Cariaco Basin during the late Quaternary.ABSTRACT: Coccoliths were studied from the ODP Hole 1002C and core PL07-39PC in the Cariaco Basin. Increases in Emiliania huxleyi are synchronous with decreases of Gephyrocapsa oceanica and vice versa. A new index (GEX) based on the relative abundances of these two taxa is proposed, and correlates with various other proxies. It is shown that GEX can serve as upwelling proxy. This confirms that the Intertropical Convergence Zone shifted north during the Bølling/Allerød, south during the Younger Dryas and back north during the Preboreal. The upwelling proxy shows few discrepancies with the terrigenous record.

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Calcareous nannoplankton biocoenosis : sediment trap studies in the equatorial Atlantic, central Pacific, and Panama Basin

Cited by 24 publications

References 39 publications

Isolation of viruses responsible for the demise of an Emiliania huxleyi bloom in the English Channel

Isolation of viruses responsible for the demise of an Emiliania huxleyi bloom in the English Channel

Phyto_ and zooplankton paleofluxes during the deposition of sapropel S1 (eastern Mediterranean): Biogenic carbonate preservation and paleoecological implications

Coccolithophores as palaeoecological indicators for shifts of the ITCZ in the Cariaco Basin during the late Quaternary

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