Meiobenthos distribution pattern in the tropical East Atlantic: indication for fractionated sedimentation of organic matter to the sea floor?


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tsoltwedel [ at ] awi-bremerhaven.de

Abstract

To test to what extent sea surface productivity governs distribution pattern of benthic organisms, meiobenthic standing stocks were investigated on the shelf, continental margin and the adjacent abyssal plains off the Western African Coast between Guinea (10°N) and Angola (18°S). The area of investigations is characterized by gradients in surface productivity due to spatial and seasonally varying coastal upwelling. Reflecting the dependency of deep-sea organisms on organic matter input from the euphotic zone, similar gradients ought to be expected within the benthos.Meiofaunal abundances and biomasses (including foraminifera) from a total of 57 stations along 13 transects across the continental margin showed a fairly close correlation with sediment-bound chloroplastic pigment concentrations, indicating the sedimentation of particulate organic matter from phytoplankton production. However, certain discrepancies in faunal and pigment distribution patterns were found in regions apart from the centres of enhanced primary productivity, i.e. apart from the upwelling centres: whereas pigment concentrations in the sediments were still comparably high, meiofaunal numbers in those peripheral areas were generally lower.It is suggested that smaller/lighter phytodetritial matter, transported over long distances by subsurface currents and exposed to ongoing microbial degradation during its passage, does probably not have the same energy content than relatively fast sinking larger phytodetritus aggregates ("marine snow") in the centres of enhanced primary productivity, which subsequently allow higher benthic stocks. Thus, meiobenthic abundances in relation to sediment-bound pigment concentrations on the Western African Continental Margin may indicate a fractionated sedimentation of organic matter to the sea floor.



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Article
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ISI/Scopus peer-reviewed
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Published
Eprint ID
2961
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Soltwedel, T. (1997): Meiobenthos distribution pattern in the tropical East Atlantic: indication for fractionated sedimentation of organic matter to the sea floor? , Marine biology:, 129 (4), pp. 747-756 .


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