Seasonal pattern of the chlorophyll-a in a coastal lagoon from the southern Baja California (Mexico), described with in situ observations and MODIS-Aqua imagery

Oceanologia

Raúl Martell-Dubois¹  María del Carmen Jiménez-Quiroz²  Rafael Cervantes-Duarte³  Sergio Cerdeira-Estrada⁴ 

[1] Corresponding author at: Dirección General Adjunta de Investigación Pesquera en el Pacífico, Instituto Nacional de Pesca y Acuacultura, Secretaría de Agricultura y Desarrollo Rural, Av. México 190, Del Carmen, Coyoacán, 04100, Mexico City, Mexico.;General Directorate for Fisheries Research in the Pacific, National Institute of Fisheries and Aquaculture, Del Carmen, Coyoacán, Mexico City, Mexico;National Commission for the Knowledge and Use of Biodiversity (CONABIO), Mexico City, Mexico;National Polytechnic Institute, Interdisciplinary Center of Marine Sciences, La Paz, Mexico;

关键词: Remote sensing;    Coastal lagoons;    Transitional zone;   

DOI  :  

来源: DOAJ

【 摘 要 】

This study aims to estimate, with a climatology perspective, the average seasonal pattern of phytoplankton biomass (SP-PBavg) and its distribution in Bahia Magdalena (Mexico) as a baseline to evaluate PB changes in future studies. This lagoon is in a semi-arid region, lacks river discharges, and channels with vegetation are limited at the north and south zones. SP-PBavg was estimated with chlorophyll-a (chl-a) data obtained in 21 sites on daily MODIS-Aqua imagery (2002–2013; n = 2,418) from a ready-to-use public database. The first step was to establish criteria to use imagery and validate with in situ observations taken in 14 sites (2002–2011; n = 312). MODIS-Aqua overestimated chl-a (mean ± confidence interval95: 5.09 ± 0.97 mg m−3; n = 225); with differences among sites. There were no differences near the inlet lagoon (p <0.05), where the water characteristics are Case-1 while values were significantly higher in the eastern shore and two or three times higher in the mouth of north and south channels, whose water characteristics are similar to Case-2. Multivariate statistical methods allow defining zones into the lagoon and describe their SP-PBavg with both in situ and MODIS Aqua data, but the former's sample size was small, and the patterns were only delineated. In the inlet surroundings, chl-a peaks from March/April to June/July. On the eastern shore, where MODIS Aqua and in situ data were correlated, despite concentration differences, chl-a is higher from March/April to October, with peaks in June and September. In the mouth of internal channels, chl-a was higher than other sites and during a longer period; however, the very high MODIS-Aqua values suggest that the satellite also detects organic matter supplied by phytoplankton and other vegetables, which explain the high lagoon's productivity. These results validate the use of MODIS Aqua imagery to describe the chl-a seasonal patterns in the sea's vicinity.

【 授权许可】

Unknown