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The production of giant marine diatoms and their export at oceanic frontal zones: implications for Si and C flux in stratified oceans

Kemp, A.E.S., Pearce, R.B., Grigorov, I., Rance, J., Lange, C.B., Quilty, P. and Salter, I. (2006) The production of giant marine diatoms and their export at oceanic frontal zones: implications for Si and C flux in stratified oceans Global Biogeochemical Cycles, 20, (4), GB4S04-[13pp]. (doi:10.1029/2006GB002698).

Record type: Article


From a synthesis of recent oceanic observations and paleo-data it is evident that certain species of giant diatoms including Rhizosolenia spp. Thalassiothrix spp. and Ethmodiscus rex may become concentrated at oceanic frontal zones and subsequently form episodes of mass flux to the sediment. Within the nutrient bearing waters advecting towards frontal boundaries, these species are generally not dominant, but they appear selectively segregated at fronts, and thus may dominate the export flux. Ancient Thalassiothrix diatom mat deposits in the eastern equatorial Pacific and beneath the Polar Front in the Southern Ocean record the highest open ocean sedimentation rates ever documented and represent vast sinks of silica and carbon. Several of the species involved are adapted to a stratified water column and may thrive in Deep Chlorophyll Maxima. Thus in oceanic regions and/or at times prone to enhanced surface water stratification (e.g., during meltwater pulses) they provide a mechanism for generating substantial biomass at depth and its subsequent export with concomitant implications for Si export and C drawdown. This ecology has important implications for ocean biogeochemical models suggesting that more than one diatom “functional type” should be used. In spite of the importance of these giant diatoms for biogeochemical cycling, their large size coupled with the constraints of conventional oceanographic survey schemes and techniques means that they are undersampled. An improved insight into these key species will be an important prerequisite for enhancing our understanding of marine biogeochemical cycling and for assessing the impacts of climate change on ocean export production.

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Submitted date: 25 January 2006
Published date: October 2006
Keywords: giant diatoms, equatorial front, polar front, deep chlorophyll maximum, stratification


Local EPrints ID: 37617
ISSN: 0886-6236
PURE UUID: 372d946f-6705-4b5c-a52a-2e65cb4e9ac4

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Date deposited: 24 May 2006
Last modified: 17 Jul 2017 15:41

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Author: A.E.S. Kemp
Author: R.B. Pearce
Author: I. Grigorov
Author: J. Rance
Author: C.B. Lange
Author: P. Quilty
Author: I. Salter

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