Chapter 17
Basic Ecosystem Dynamics in the Red Sea as
Seen by Sundry Remote Sensing Techniques
Vittorio Barale and Martin Gade
Abstract Patterns of algal blooming are considered to be indicators of basic ecosystem dynamics in marginal and enclosed seas. A time series of chlorophyll-like
pigment concentration (chl)–which can be interpreted as a proxy of biomass and,
under certain circumstances, productivity–derived from SeaWiFS data, from July
1999 to June 2009, was considered to explore the space–time variability of algal
blooming in the Red Sea. The comparison with concurrent surface wind speed (ws)
and direction, derived from QuikSCAT data, allowed to correlate chl variability with
atmospheric forcing. The observed chl seasonality is essentially bimodal, with a
fall-winter period of extended blooming, progressing from south to north and back,
followed by a spring-summer period of reduced blooming, at least in the northern
sub-basin. This annual cycle seems to match the climatic characteristics of the basin,
the monsoon-driven wind regime in particular, and the ensuing thermohaline circulation. The correlation with ws suggests that the Red Sea behaves like a classical
sub-tropical basin, where production is never limited by sunlight, but always limited
by nutrient availability–a condition relaxed only in the colder season, when (winddriven) convection processes can enrich the euphotic zone with nutrients from deeper
layers. However, at the same time, it appears that other blooming episodes, in the
southern sub-basin in particular, are not driven directly by the wind field, but rather
by other factors such as the exchange of water with the Arabian Sea, via the Gulf of
Aden and Bab-el-Mandeb.
V. Barale ()
European Commission, Joint Research Centre,
Institute for Environment and Sustainability,
Ispra, Italy
e-mail: vittorio.barale@jrc.ec.europa.eu
M. Gade
Institut für Meereskunde, Universität Hamburg,
Hamburg, Germany
e-mail: martin.gade@uni-hamburg.de
V. Barale, M. Gade (eds.), Remote Sensing of the African Seas,
337
DOI 10.1007/978-94-017-8008-7_17,
© Springer Science+Business Media Dordrecht 2014
Basic Ecosystem Dynamics in the Red Sea as
Seen by Sundry Remote Sensing Techniques
Vittorio Barale and Martin Gade
Abstract Patterns of algal blooming are considered to be indicators of basic ecosystem dynamics in marginal and enclosed seas. A time series of chlorophyll-like
pigment concentration (chl)–which can be interpreted as a proxy of biomass and,
under certain circumstances, productivity–derived from SeaWiFS data, from July
1999 to June 2009, was considered to explore the space–time variability of algal
blooming in the Red Sea. The comparison with concurrent surface wind speed (ws)
and direction, derived from QuikSCAT data, allowed to correlate chl variability with
atmospheric forcing. The observed chl seasonality is essentially bimodal, with a
fall-winter period of extended blooming, progressing from south to north and back,
followed by a spring-summer period of reduced blooming, at least in the northern
sub-basin. This annual cycle seems to match the climatic characteristics of the basin,
the monsoon-driven wind regime in particular, and the ensuing thermohaline circulation. The correlation with ws suggests that the Red Sea behaves like a classical
sub-tropical basin, where production is never limited by sunlight, but always limited
by nutrient availability–a condition relaxed only in the colder season, when (winddriven) convection processes can enrich the euphotic zone with nutrients from deeper
layers. However, at the same time, it appears that other blooming episodes, in the
southern sub-basin in particular, are not driven directly by the wind field, but rather
by other factors such as the exchange of water with the Arabian Sea, via the Gulf of
Aden and Bab-el-Mandeb.
V. Barale ()
European Commission, Joint Research Centre,
Institute for Environment and Sustainability,
Ispra, Italy
e-mail: vittorio.barale@jrc.ec.europa.eu
M. Gade
Institut für Meereskunde, Universität Hamburg,
Hamburg, Germany
e-mail: martin.gade@uni-hamburg.de
V. Barale, M. Gade (eds.), Remote Sensing of the African Seas,
337
DOI 10.1007/978-94-017-8008-7_17,
© Springer Science+Business Media Dordrecht 2014