Depth-stratified phytoplankton dynamics in Cyclone Opal, a subtropical mesoscale eddy SCIE SCOPUS

Cited 73 time in WEB OF SCIENCE Cited 74 time in Scopus
Title
Depth-stratified phytoplankton dynamics in Cyclone Opal, a subtropical mesoscale eddy
Author(s)
Landry, Michael R.; Brown, Susan L.; Rii, Yoshimi M.; Selph, Karen E.; Bidigare, Robert R.; Yang, Eun Jin; Simmons, Melinda P.
Publication Year
2008-05
Abstract
As part of E-Flux III cruise studies in March 2005, we investigated phytoplankton community dynamics in a cyclonic cold-core eddy (Cyclone Opal) in the lee of the Hawaiian Islands. Experimental incubations were conducted under in situ temperature and light conditions on a drift array using a two-treatment dilution technique. Taxon-specific estimates of growth, grazing and production rates were obtained from analyses of incubation results based on phytoplankton pigments, flow cytometry and microscopy. Cyclone Opal was sampled at a biologically and physically mature state, with an 80-100m doming of isopycnal surfaces in its central region and a deep biomass maximum of large diatoms. Depth-profile experimentation defined three main zones. The upper (mixed) zone (0-40m), showed little compositional or biomass response to eddy nutrient enrichment, but growth, grazing and production rates were significantly enhanced in this layer relative to the ambient community outside of the eddy. Prochlorococcus spp. dominated the upper mixed layer, accounting for 50-60% of its estimated primary production both inside and outside of Opal. In contrast, the deep zone of 70-90 m showed little evidence of growth rate enhancement and was principally defined by a similar to 100-fold increase of large (> 20-mu m) diatoms and a shift from Prochlorococcus to diatom dominance (similar to 80%) of production. The intermediate layer of 50-60 m marked the transition between the upper and lower extremes but also contained an elevated biomass of physiologically unhealthy diatoms with significantly depressed growth rates and proportionately greater grazing losses relative to diatoms above or below. Microzooplankton grazers consumed 58%, 65% and 55%, respectively, of the production of diatoms, Prochlorococcus and the total phytoplankton community in Cyclone Opal. The substantial grazing impact on diatoms suggests that efficient recycling was the major primary fate of diatom organic production, consistent with the low export fluxes and selective export of biogenic silica, as empty diatom frustules, in Cyclone Opal. (C) 2008 Elsevier Ltd. All rights reserved.
ISSN
0967-0645
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/4509
DOI
10.1016/j.dsr2.2008.02.001
Bibliographic Citation
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY, v.55, no.10-13, pp.1348 - 1359, 2008
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Subject
EASTERN EQUATORIAL PACIFIC; MICROBIAL COMMUNITY STRUCTURE; IRON FERTILIZATION; SARGASSO SEA; BIOLOGICAL RESPONSE; SOUTHERN-OCEAN; ARABIAN SEA; GROWTH; ATLANTIC; CARBON
Keywords
physical-biological coupling; Prochlorococcus; diatom bloom; microzooplankton grazing; growth rate
Type
Article
Language
English
Document Type
Article
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
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