Seasonal and interannual variability of chlorophyll a and primary production in the Equatorial Atlantic: in situ and remote sensing observations |
| |
Authors: | Perez, Valesca Fernandez, Emilio Maranon, Emilio Serret, Pablo Garcia-Soto, Carlos |
| |
Affiliation: | 1 Facultad de Ciencias del Mar, Universidad de Vigo, E-36310 Vigo, Spain and 2 Instituto Español de Oceanografía, Centro Oceanográfico de Santander, APDO 240, E-39080 Santander, Spain |
| |
Abstract: | The seasonal variability of phytoplankton in the EquatorialAtlantic was analysed using Sea-viewing Wide Field-of-view Sensor(SeaWiFS)-derived chlorophyll a (Chl a) concentration data from1998 to 2001, together with in situ Chl a and primary productiondata obtained during seven cruises carried out between 1995and 2000. Monthly averaged SeaWiFS Chl a distributions werein agreement with previous observations in the Equatorial Atlantic,showing marked differences between 10° W in the EasternTropical Atlantic (ETRA) and 25° W in the Western TropicalAtlantic (WTRA) provinces (Longhurst et al. 1995. J. PlanktonRes., 17, 12451271). The seasonal cycle of SeaWiFS-derivedChl a concentration calculated for 010° S, 020°W (ETRA) is consistent with in situ Chl a measurements, withvalues ranging from 0.16 mg m3, from February to April,to 0.52 mg m3 in August. Lower variability was observedin 10° N10° S, 2030° W (WTRA) whereminimum and maximum concentrations occurred in April (0.15 mgm3) and in August (0.24 mg m3), respectively.A significant empirical relationship between depth-integratedprimary production and in situ measured sea surface Chl a wasfound for ETRA, allowing us to estimate the seasonal cycle ofdepth-integrated primary production from SeaWiFS-derived Chla. As for Chl a, this model was verified in a small area ofthe Eastern Equatorial Atlantic (010° S, 020°W), although in this instance it was not completely able todescribe the magnitude and temporal variability of in situ primaryproduction measurements. The annual euphotic depth-integratedprimary production rate estimated for ETRA by our empiricalmodel was 1.4 Gt C year1, which represents 16% of theopen ocean primary production estimated for the whole AtlanticOcean. |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|