TY - JOUR
T1 - Front-Eddy Influence on Water Column Properties, Phytoplankton Community Structure, and Cross-Shelf Exchange of Diatom Taxa in the Shelf-Slope Area off Concepción (∼36–37°S)
AU - Morales, Carmen E.
AU - Anabalón, Valeria
AU - Bento, Joaquim P.
AU - Hormazabal, Samuel
AU - Cornejo, Marcela
AU - Correa-Ramírez, Marco A.
AU - Silva, Nelson
N1 - Funding Information:
We are thankful to the captain and crew of the R/V Abate Molina (IFOP, Chile), and to the technical staff and students participating in the PHYTO- FRONT survey for their invaluable help at sea and initial data processing. V. Anabalón benefited from a CONICYT fellowship (Becas de Doctorado en el Extranjero por Gestión Propia 2008 - Becas Chile 2009) and this work was completed while V. Anabalón was a Ph.D. student in the IOCAG Doctoral Programme in Oceanography and Global Change at the ULPGC in Spain. C.E. Morales and S. Hormazabal were supported by CONICYT-FONDECYT (Projects 1120504 and 1151299) and, together with M. Cornejo, by the Instituto Milenio de Oceanografía (IMO-Chile). We acknowledge the contribution of Pierre-Amael Auger with the eddy-tracking algorithm and his comments on this subject. Satellite Chl-a data used in this study are available from SeaWiFS/MODIS-Sea- viewing Wide Field-of-view Sensor/ Moderate Resolution Imaging Spectro radiometer on the NASA Aqua satellites (http://oceancolor.gsfc.nasa. gov). The Group for High Resolution Sea Surface Temperature (GHRSST) Multi-scale Ultra-high Resolution (MUR) SST data were obtained from the NASA EOSDIS Physical Oceanography Distributed Active Archive Center (PO.DAAC) at the Jet Propulsion Laboratory, Pasadena, CA (https://doi.org/10.5067/GHGMR- 4FJ01). Multimission altimeter products are produced by SSALTO/ Duacs and distributed by AVISO (www. aviso.oceanobs.com). The data included in this study are listed in the figures, URLs in the text, and/or references. In addition, in situ and satellite data used in this study are available upon request from C.E. Morales (camorale@udec.cl) and S. Hormazabal (samuel.hormazabal@ pcuv.cl), respectively. Finally, we thank the very useful comments by two anonymous reviewers.
Publisher Copyright:
© 2017. The Authors.
PY - 2017/11
Y1 - 2017/11
N2 - In eastern boundary current systems (EBCSs), submesoscale to mesocale variability contributes to cross-shore exchanges of water properties, nutrients, and plankton. Data from a short-term summer survey and satellite time series (January–February 2014) were used to characterize submesoscale variability in oceanographic conditions and phytoplankton distribution across the coastal upwelling and coastal transition zones north of Punta Lavapié, and to explore cross-shelf exchanges of diatom taxa. A thermohaline front (FRN-1) flanked by a mesoscale anticyclonic intrathermocline eddy (ITE-1), or mode-water eddy, persisted during the time series and the survey was undertaken during a wind relaxation event. At the survey time, ITE-1 contributed to an onshore intrusion of warm oceanic waters (southern section) and an offshore advection of cold coastal waters (northern section), with the latter forming a cold, high chlorophyll-a filament. In situ phytoplankton and diatom biomasses were highest at the surface in FRN-1 and at the subsurface in ITE-1, whereas values in the coastal zone were lower and dominated by smaller cells. Diatom species typical of the coastal zone and species dominant in oceanic waters were both found in the FRN-1 and ITE-1 interaction area, suggesting that this mixture was the result of both offshore and onshore advection. Overall, front-eddy interactions in EBCSs could enhance cross-shelf exchanges of coastal and oceanic plankton, as well as sustain phytoplankton growth in the slope area through localized upward injections of nutrients in the frontal zone, combined with ITE-induced advection and vertical nutrient inputs to the surface layer.
AB - In eastern boundary current systems (EBCSs), submesoscale to mesocale variability contributes to cross-shore exchanges of water properties, nutrients, and plankton. Data from a short-term summer survey and satellite time series (January–February 2014) were used to characterize submesoscale variability in oceanographic conditions and phytoplankton distribution across the coastal upwelling and coastal transition zones north of Punta Lavapié, and to explore cross-shelf exchanges of diatom taxa. A thermohaline front (FRN-1) flanked by a mesoscale anticyclonic intrathermocline eddy (ITE-1), or mode-water eddy, persisted during the time series and the survey was undertaken during a wind relaxation event. At the survey time, ITE-1 contributed to an onshore intrusion of warm oceanic waters (southern section) and an offshore advection of cold coastal waters (northern section), with the latter forming a cold, high chlorophyll-a filament. In situ phytoplankton and diatom biomasses were highest at the surface in FRN-1 and at the subsurface in ITE-1, whereas values in the coastal zone were lower and dominated by smaller cells. Diatom species typical of the coastal zone and species dominant in oceanic waters were both found in the FRN-1 and ITE-1 interaction area, suggesting that this mixture was the result of both offshore and onshore advection. Overall, front-eddy interactions in EBCSs could enhance cross-shelf exchanges of coastal and oceanic plankton, as well as sustain phytoplankton growth in the slope area through localized upward injections of nutrients in the frontal zone, combined with ITE-induced advection and vertical nutrient inputs to the surface layer.
KW - coastal upwelling
KW - cross-shelf exchange
KW - diatom taxa
KW - eastern South Pacific
KW - frontal zone
KW - mesoscale eddies
KW - nutrient distribution
KW - phytoplankton community structure
UR - http://www.scopus.com/inward/record.url?scp=85034604896&partnerID=8YFLogxK
U2 - 10.1002/2017JC013111
DO - 10.1002/2017JC013111
M3 - Article
AN - SCOPUS:85034604896
VL - 122
SP - 8944
EP - 8965
JO - Journal of Geophysical Research: Oceans
JF - Journal of Geophysical Research: Oceans
SN - 2169-9275
IS - 11
ER -