Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico

Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico

Sixteen monthly cruises were carried out at a station 6.5 km to the NW of the mouth of Magdalena Bay (Mexico) to study the temporal variability of phytoplankton biomass and primary production rates, and the response of phytoplankton to the prevailing hydrographic characteristics. During each cruise,...

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主要な著者: Cervantes-Duarte, Rafael, Barón-Campis, Sofía, Hernández-Becerril, David Uriel, Gaxiola-Castro, Gilberto, Lara-Lara, J Rubén
フォーマット: info:eu-repo/semantics/article
言語:eng
出版事項: Iniversidad Autónoma de Baja California 2018
オンライン･アクセス:https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/2744
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id repositorioinstitucional-20.500.12930-7522
record_format dspace
institution Repositorio Institucional
collection DSpace
language eng
description Sixteen monthly cruises were carried out at a station 6.5 km to the NW of the mouth of Magdalena Bay (Mexico) to study the temporal variability of phytoplankton biomass and primary production rates, and the response of phytoplankton to the prevailing hydrographic characteristics. During each cruise, temperature and salinity were measured in the water column, and discrete samples were collected to measure inorganic nutrient concentrations (nitrate, phosphate, and silicate) and chlorophyll a content (as a proxy for phytoplankton biomass); in addition, in situ incubations were performed to estimate primary production (PP) rates using the 14C technique. During spring and early summer (March–July), the water column at the study site was cold (14.4 ºC at 80 m depth and 17.7 ºC at the surface) and well mixed, with high nutrient concentrations (nitrate = 6.39 μM, phosphate = 0.91 μM, and silicate = 11.87 μM) at the surface, typical of intense upwelling systems. On the contrary, from August to February the water column was stratified (23.5 ± 3.2 ºC above the thermocline and 17.0 ± 1.7 ºC at 80 m depth) and had low nutrient concentrations (nitrate = 3.90 μM, phosphate = 0.47 μM, and silicate = 10.30 μM) at the surface. Phytoplankton abundance, chlorophyll a concentration, and PP rates in the euphotic zone were higher during the upwelling season, with maximum cell density of 1.7 × 106 cells·L–1 (nanoplankton fraction), integrated chlorophyll a content of 231 mg·m–2, and integrated PP rates of 553 mg C·m–2·h–1). Abundance of cells <20 μm, as determined by flow cytometry, revealed the importance of the nanoplankton and picoplankton fractions in this region. This study showed the seasonal variability of phytoplankton communities (biomass and productivity) in waters off Magdalena Bay and the coupling of phytoplankton to environmental variability. Seasonal variability was similar to that observed for other typical coastal upwelling regions, that is, higher phytoplankton abundances and PP rates in spring and summer and lower values in autumn and winter. Key words: biomass, primary productivity, hydrography, coastal zone, Magdalena Bay.
format info:eu-repo/semantics/article
author Cervantes-Duarte, Rafael
Barón-Campis, Sofía
Hernández-Becerril, David Uriel
Gaxiola-Castro, Gilberto
Lara-Lara, J Rubén
spellingShingle Cervantes-Duarte, Rafael
Barón-Campis, Sofía
Hernández-Becerril, David Uriel
Gaxiola-Castro, Gilberto
Lara-Lara, J Rubén
Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico
author_facet Cervantes-Duarte, Rafael
Barón-Campis, Sofía
Hernández-Becerril, David Uriel
Gaxiola-Castro, Gilberto
Lara-Lara, J Rubén
author_sort Cervantes-Duarte, Rafael
title Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico
title_short Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico
title_full Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico
title_fullStr Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico
title_full_unstemmed Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico
title_sort temporal variability of phytoplankton biomass and primary production off magdalena bay, baja california sur, mexico
publisher Iniversidad Autónoma de Baja California
publishDate 2018
url https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/2744
_version_ 1792609983255281664
spelling repositorioinstitucional-20.500.12930-75222023-05-09T14:30:50Z Temporal variability of phytoplankton biomass and primary production off Magdalena Bay, Baja California Sur, Mexico Variabilidad temporal de la biomasa y la producción primaria del fitoplancton frente a bahía Magdalena, Baja California Sur, México Cervantes-Duarte, Rafael Barón-Campis, Sofía Hernández-Becerril, David Uriel Gaxiola-Castro, Gilberto Lara-Lara, J Rubén Sixteen monthly cruises were carried out at a station 6.5 km to the NW of the mouth of Magdalena Bay (Mexico) to study the temporal variability of phytoplankton biomass and primary production rates, and the response of phytoplankton to the prevailing hydrographic characteristics. During each cruise, temperature and salinity were measured in the water column, and discrete samples were collected to measure inorganic nutrient concentrations (nitrate, phosphate, and silicate) and chlorophyll a content (as a proxy for phytoplankton biomass); in addition, in situ incubations were performed to estimate primary production (PP) rates using the 14C technique. During spring and early summer (March–July), the water column at the study site was cold (14.4 ºC at 80 m depth and 17.7 ºC at the surface) and well mixed, with high nutrient concentrations (nitrate = 6.39 μM, phosphate = 0.91 μM, and silicate = 11.87 μM) at the surface, typical of intense upwelling systems. On the contrary, from August to February the water column was stratified (23.5 ± 3.2 ºC above the thermocline and 17.0 ± 1.7 ºC at 80 m depth) and had low nutrient concentrations (nitrate = 3.90 μM, phosphate = 0.47 μM, and silicate = 10.30 μM) at the surface. Phytoplankton abundance, chlorophyll a concentration, and PP rates in the euphotic zone were higher during the upwelling season, with maximum cell density of 1.7 × 106 cells·L–1 (nanoplankton fraction), integrated chlorophyll a content of 231 mg·m–2, and integrated PP rates of 553 mg C·m–2·h–1). Abundance of cells <20 μm, as determined by flow cytometry, revealed the importance of the nanoplankton and picoplankton fractions in this region. This study showed the seasonal variability of phytoplankton communities (biomass and productivity) in waters off Magdalena Bay and the coupling of phytoplankton to environmental variability. Seasonal variability was similar to that observed for other typical coastal upwelling regions, that is, higher phytoplankton abundances and PP rates in spring and summer and lower values in autumn and winter. Key words: biomass, primary productivity, hydrography, coastal zone, Magdalena Bay. En el periodo de la primavera de 2013 al verano de 2014 se llevaron a cabo 16 muestreos mensuales a 6.5 km al noroeste de la boca de bahía Magdalena (México) con el propósito de estudiar la variabilidad temporal de la biomasa y las tasas de producción primaria del fitoplancton y la respuesta del mismo a las características hidrográficas predominantes. En cada muestreo se midieron la temperatura y salinidad en la columna de agua y se determinaron las concentraciones de nutrientes inorgánicos (nitrato, fosfato y silicato) y el contenido de clorofila a (como proxy de la biomasa del fitoplancton); además, se hicieron incubaciones in situ para estimar la producción primaria (PP) con el método de 14C. En primavera y principios de verano (marzo–julio), el sitio presentó, en promedio, una columna de agua fría (14.4 ºC a 80 m de profundidad y 17.7 ºC en superficie) y mezclada con concentraciones de nutrientes altas en superficie (nitrato = 6.39 μM, fosfato = 0.91 μM y silicato = 11.87μM; valores característicos de zonas de afloramiento intenso). Por el contrario, de agosto a febrero se observó una columna de agua estratificada (23.5 ± 3.2 ºC arriba de la termoclina y 17.0 ± 1.7 ºC a 80 m de profundidad) con menor contenido de nutrientes en superficie (nitrato = 3.90 μM, fosfato = 0.47 μM y silicato = 10.30 μM). La abundancia del fitoplancton, la concentración de clorofila a y las tasas de PP en la zona eufótica fueron mayores en la temporada de surgencias, con densidad celular máxima de 1.7 × 106 cél·L–1 (fracción del nanoplancton), contenido de clorofila a integrada de 231 mg·m–2 y tasa de producción integrada de 553 mg C·m–2·h–1. Las abundancias de células <20 μm determinadas por citometría de flujo mostraron la importancia de las fracciones del nano y picoplancton en la región. Este estudio mostró la variabilidad estacional de las comunidades del fitoplancton (biomasa y productividad) en las aguas frente a bahía Magdalena y su acoplamiento al cambio ambiental. La variabilidad estacional fue similar a la observada en otras regiones características de afloramientos costeros, esto es, mayores abundancias y tasas de PP en primavera y verano y valores menores en otoño e invierno. Palabras clave: biomasa, productividad primaria, hidrografía, zona costera, bahía Magdalena. 2018-06-25 2021-06-03T03:55:34Z 2021-06-03T03:55:34Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article Artículo Arbitrado https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/2744 10.7773/cm.v44i2.2744 https://hdl.handle.net/20.500.12930/7522 eng https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/2744/420420442 Copyright (c) 2018 Ciencias Marinas application/pdf Iniversidad Autónoma de Baja California Ciencias Marinas; Vol. 44 No. 2 (2018); 91–105 Ciencias Marinas; Vol. 44 Núm. 2 (2018); 91–105 2395-9053 0185-3880

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