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Tracking the history of dinoflagellate cyst assemblages in sediments from the west coast of India

DRS at CSIR-National Institute of Oceanography

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Title Tracking the history of dinoflagellate cyst assemblages in sediments from the west coast of India
 
Creator DeSilva, M.S.
Anil, A.C.
Borole, D.V.
Nath, B.N.
Singhal, R.K.
 
Subject algal blooms
cysts
sediments
sedimentation
Gonyaulax spinifera
Lingulodinium polyedrum
Protoceratium reticulatum
Scrippsiella trochoidea
 
Description In order to trace the history of dinoflagellate cyst assemblages and provide new insights in to Harmful Algal Bloom (HAB) dynamics in monsoon influenced tropical environments, sediment cores were collected from four different coastal locations along the west coast of India. The naturally occurring radionuclide sup(210) Pb activity in the sediment samples were measured; and subsequently the sedimentation rates (SRs) and ages were modeled. The SRs ranged from 0.15 plus or minus 0.01 to 2.80 plus or minus 0.38 cm/yr and provided coverage of time period spanning between 21 and 145 yr. Cysts of potential harmful dinoflagellates (Gonyaulax spinifera, Lingulodinium polyedrum, Protoceratium reticulatum and Scrippsiella trochoidea) were observed to be present earlier than the 20th century. Among the four sediment cores, significant temporal variations in cyst abundance were observed in the sediment core, off Mangalore. Two of the cores from off Mangalore and Cannanore were dominated by autotrophic cyst assemblages (Gonyaulax membranacea and Gonyaulax spinifera) in the deeper sediment sections. However, the upper sediment sections were dominated by heterotrophic forms. Temporal shifts in cyst assemblages from autotrophic to heterotrophic dinoflagellates in the Mangalore core coincided with high deposition of shells; carbon analyses (Delta 13C sub(org) and C sub(org):N ratio) revealed shifts in organic matter type from terrestrial to marine source. The terrigenous input in this region, influenced by the monsoonal variations, can thus affect dinoflagellate assemblage structure and lead to changes in ecosystem functioning.
 
Date 2012-09-03T05:00:15Z
2012-09-03T05:00:15Z
2012
 
Type Journal Article
 
Identifier Journal of Sea Research, vol.73; 2012; 86-100
no
http://drs.nio.org/drs/handle/2264/4142
 
Language en
 
Relation J_Sea_Res_73_86.jpg
 
Rights An edited version of this paper was published by Elsevier. Copyright [2012] Elsevier
 
Publisher Elsevier