Oceanographic conditions over the continental shelf off Magdalena Bay (Mexico) in 2011–2012

Zaytsev, Oleg; Trasviña-Castro, Armando; Linero-Cueto, Jean; Gaxiola‐Castro, Gilberto; Cepeda-Morales, Jushiro

doi:10.7773/cm.v40i2.2314

Cited by 28 publications

(20 citation statements)

References 13 publications

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“…Consistent with the geostrophic surface circulation obtained from the combination of satellite and tide gauge data [ Strub and James , , Figure 3], the modeled circulation showed a cyclonic eddy—centered at ∼27°N (Figure b)—that dominated the coastal circulation near Punta Eugenia. Recent studies exhibit a quasi‐permanent surface poleward flow off ∼25°N [ Zaitsev et al ., ; Valle Rodríguez , ], our numerical implementation also reproduced a long‐term mean surface poleward flow there (Figure b).…”

Section: Mean Circulationmentioning

confidence: 99%

Semiannual variability of the California Undercurrent along the Southern California Current System: A tropical generated phenomenon

Gómez-Valdivia

Parés‐Sierra²,

Flores-Morales³

2017

J. Geophys. Res. Oceans

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We used a high‐resolution numerical model implementation to analyze the California Undercurrent (CU) dynamics along the Southern California Current System. In agreement with reported observations, the modeled CU was stronger during June–July and December–January, when it flowed continuously along Baja California and Southern California reaching long‐term averages up to 6 cm s−1. Previous research has associated the biannual CU intensification to the local dynamics off Southern California. Our results evidenced, however, that the passage of remote Semiannual Coastal‐Trapped Waves (SCTW) primarily explained the semiannual CU variability. The CU was stronger 2–3 months after the passage of the upwelling SCTW phase, when the offshore propagation of Rossby waves, brought about by the SCTW transit, induced an energetic cross‐shore pressure gradient that strengthened the subsurface poleward circulation along the continental slope. The SCTW were independent of the local wind; they corresponded to the northward extension of semiannual equatorial Kelvin waves that have been observed along the northeastern tropical Pacific.

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Section: Mean Circulationmentioning

confidence: 99%

Semiannual variability of the California Undercurrent along the Southern California Current System: A tropical generated phenomenon

Gómez-Valdivia

Parés‐Sierra²,

Flores-Morales³

2017

J. Geophys. Res. Oceans

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“…As a result, the tropical coastal region shows peak ADT and SST (~82 cm and ~30°C) along with the lowest EkP (~18 cm d −1 ) and relatively low CHL (~1.0 mg m −3 ) (Figure ). Moreover, the Mexican Coastal Current conveys warm tropical water toward the subtropical zone [ Zaitsev et al , ], depicted in Figure c, which shows an intense poleward geostrophic flow alongshore in the tropical zone that becomes apparent nearshore along the peninsula in autumn (Figure d). In spite of the influence of warm water in summer, high CHL levels are observed off the Baja California coast (~8.0 mg m −3 ) with a positive EkP (~70 cm d −1 ), lower than that observed in spring.…”

Section: Resultsmentioning

confidence: 99%

Approach for estimating the dynamic physical thresholds of phytoplankton production and biomass in the tropical‐subtropical Pacific Ocean

2017

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Threshold is defined as the point where small changes in an environmental driver produce large responses in the ecosystem. Generalized additive models (GAMs) were used to estimate the thresholds and contribution of key dynamic physical variables in terms of phytoplankton production and variations in biomass in the tropical‐subtropical Pacific Ocean off Mexico. The statistical approach used here showed that thresholds were shallower for primary production than for phytoplankton biomass (pycnocline < 68 m and mixed layer < 30 m versus pycnocline < 45 m and mixed layer < 80 m) but were similar for absolute dynamic topography and Ekman pumping (ADT < 59 cm and EkP > 0 cm d−1 versus ADT < 60 cm and EkP > 4 cm d−1). The relatively high productivity on seasonal (spring) and interannual (La Niña 2008) scales was linked to low ADT (45–60 cm) and shallow pycnocline depth (9–68 m) and mixed layer (8–40 m). Statistical estimations from satellite data indicated that the contributions of ocean circulation to phytoplankton variability were 18% (for phytoplankton biomass) and 46% (for phytoplankton production). Although the statistical contribution of models constructed with in situ integrated chlorophyll a and primary production data was lower than the one obtained with satellite data (11%), the fits were better for the former, based on the residual distribution. The results reported here suggest that estimated thresholds may reliably explain the spatial‐temporal variations of phytoplankton in the tropical‐subtropical Pacific Ocean off the coast of Mexico.

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“…En promedio, la saturación de oxigeno disminuyó de ≈100 % en la superficie al fondo (33% en junio, 67% en agosto y 79% en noviembre). Los valores mínimos registrados en junio es posible que se deban al origen subsuperficial del agua (aproximadamente 80 m) transportada hacia la superficie por el proceso de surgencia costera Zaitsev et al, 2014). En verano y otoño (agosto y noviembre) los valores de oxígeno debajo de la superficie tienden a disminuir de manera normal por el aumento de temperatura en el año y el aumento en la tasa de respiración de los organismos.…”

Section: Discussionunclassified

Tidal effect on the nutrients, chlorophyll-a concentration, and physical-chemical parameters in a subtropical coastal lagoon (Bahía Magdalena, Mexico)

2017

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Efecto de la marea en la concentración de nutrientes, clorofila a y parámetros físicos y químicos en una laguna costera subtropical (Bahía Magdalena, México) Tidal effect on the nutrients, chlorophyll-a concentration, and physical-chemical parameters in a subtropical coastal lagoon (Bahía Magdalena, Mexico) . 2017. Efecto de la marea en la concentración de nutrientes, clorofila a y parámetros físicos y químicos en una laguna costera subtropical (Bahía Magdalena, México). Hidrobiológica 27 (2): 253-264. DOI: 10.24275/uam/izt/dcbs/hidro/2017v27n2/CervantesD RESUMEN Antecedentes. Bahía Magdalena es una laguna costera subtropical de alta importancia ecológica y pesquera del noroeste (NO) de México, donde se requiere consolidar el conocimiento de los procesos hidrodinámicos y la calidad de sus aguas para mejorar su aprovechamiento. Objetivos. Analizar la influencia de la marea en la variación y transporte de nutrientes y clorofila a entre la laguna y el océano adyacente como mecanismo de fertilización de la región. Métodos. Se realizaron tres muestreos en junio, agosto y noviembre de 2005 en un sitio aproximadamente a 5 km de la boca (24 o 57´ N y 112 o 03´ O). Se tomaron muestras cada 2 horas durante cada ciclo de marea para medir nutrientes, clorofila a y oxígeno a tres profundidades (0, 15 y 30 m), así como temperatura y salinidad mediante un CTD. Resultados. Se identificaron tres condiciones climático-oceanográficas: surgencias (junio), estratificación (agosto) y ENSO (El Niño Southern Oscilation) negativo (noviembre). La relación entre amplitud de marea y las variables medidas fue mayor en agosto (p < 0.05) respecto a junio y noviembre. Conclusiones. El transporte neto de nutrientes por ciclo de marea depende de la época del año y el estado de la marea y se considera alto comparado con otros sistemas de menores dimensiones y explica la elevada productividad orgánica en esta región costera.Palabras clave: Estuario negativo, fosfato, nitrógeno, oxígeno, transporte neto. ABSTRACTBackground. Magdalena Bay is a subtropical coastal lagoon of northwestern Mexico with important ecological considerations and numerous fisheries. Knowledge of hydrodynamics and water quality are essential for establishing best management practices for the Bay. Goals. The aim of the study was to analyze the influence of the tide on the variation and transport of nutrients and chlorophyll a between the inner lagoon and the adjacent ocean as a fertilization mechanism in the area. Methods. Samples were obtained in June, August, and November 2005 at a site close to the mouth (24 o 57´ N and 112 o 03´ W). The samples were obtained every 2 hours during each tidal cycle at three different depths (0, 15, and 30 m). Temperature and salinity were measured using a CTD. Nutrients, chlorophyll a, and oxygen were measured at a laboratory. Results. Three climatic-oceanographic conditions were identified: upwelling (June), stratification (August), and negative effects during the ENSO (November). The correlation between tidal range and other variables was ...

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Oceanographic conditions over the continental shelf off Magdalena Bay (Mexico) in 2011–2012

Cited by 28 publications

References 13 publications

Semiannual variability of the California Undercurrent along the Southern California Current System: A tropical generated phenomenon

Semiannual variability of the California Undercurrent along the Southern California Current System: A tropical generated phenomenon

Approach for estimating the dynamic physical thresholds of phytoplankton production and biomass in the tropical‐subtropical Pacific Ocean

Tidal effect on the nutrients, chlorophyll-a concentration, and physical-chemical parameters in a subtropical coastal lagoon (Bahía Magdalena, Mexico)

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