Premium
Satellite observations of the impact of dust in a low‐nutrient, low‐chlorophyll region: Fertilization or artifact?
Author(s) -
Volpe Gianluca,
Banzon Viva F.,
Evans Robert H.,
Santoleri Rosalia,
Mariano Arthur J.,
Sciarra Roberto
Publication year - 2009
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2008gb003216
Subject(s) - phytoplankton , environmental science , chlorophyll a , aerosol , mediterranean sea , nutrient , atmospheric sciences , oceanography , satellite , ocean color , lag , mediterranean climate , mineral dust , geology , physics , biology , meteorology , ecology , botany , astronomy , computer network , computer science
The coupling between dust aerosols and phytoplankton concentrations in the Mediterranean Sea, a low‐nutrient, low‐chlorophyll region, is examined at different timescales using Sea‐viewing Wide Field‐of‐view Sensor observations (1998–2002). Aerosol optical thickness (AOT) and chlorophyll (MCHL) were used as proxies for dust aerosol and phytoplankton biomass, respectively. The AOT data was qualified using quasi‐true color images in order to ascertain the presence of dust. Strong positive correlations were found between AOT and MCHL on weekly but not on seasonal timescales. However, weekly analyses cannot distinguish between real phytoplankton response and artifacts due to residual dust in the atmosphere or water. Daily time series of AOT and MCHL, for single‐dust events, and their temporal cross‐correlation function were analyzed. Apparent AOT‐driven MCHL increases principally occurred within 0–2 days and most cross correlations were significant at zero lag. In contrast, significant negative or positive correlations at lag greater than 2 days were very few, indicating no compelling evidence that dust enhancement of phytoplankton growth is significant and that the response at near‐zero lags is an artifact of the satellite data processing. Our analysis demonstrates that the dust fertilization does not play a significant role in the sustainment of the phytoplankton dynamics in the Mediterranean Sea.