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Envisat’s MERIS captures phytoplankton bloom   An example of phytoplankton cell  This image features eastern Canada and three of its provinces. Quebec is in the top left corner. Part of Newfoundland is visible as the island partially covered by clouds in the top centre of the image. Part of Nova Scotia can be seen as well in the left part of the image. The most interesting feature present on this image is the large milky turquoise patch off the southern coast of Newfoundland. The colour of the water is due to the bloom of tiny algae called phytoplankton. This phytoplankton bloom was first observed by the Medium Resolution Imaging Spectrometer (MERIS) on the 24th of July and followed by the instrument during its development until the 13th of August 2002. Technical Information: Instrument: MEdium Resolution Imaging Spectrometer (MERIS) Date of Acquisition: 10 August 2002 Orbit number: 02326 Instrument features: Reduced Resolution image (1200-meter resolution) MERIS was designed to measure the concentration of phytoplankton. The colours seen by MERIS indicate the concentration of chlorophyll, the pigment that phytoplankton use for photosynthesis. MERIS can detect chlorophyll concentrations as low as 0.01 microgram, or 1/100 000 000 of a gram, per litre. MERIS data will be used to monitor the worldwide distribution of phytoplankton and to compute primary production. Blooming off-season  The large milky turquoise patch visible below the southern coast of Newfoundland, Canada, is a bloom of tiny algae called phytoplankton. Also seen in this image is a portion of Nova Scotia on the left side of the image. This phytoplankton bloom was observed by the Medium Resolution Imaging Spectrometer (MERIS) on ESA’s Envisat satellite in a series of image acquisitions from 24 July to 13 August 2002.  The large milky turquoise patch visible below the southern coast of Newfoundland, Canada, is a bloom of tiny algae called phytoplankton. Also seen in this image is a portion of Nova Scotia on the left side of the image. This phytoplankton bloom was observed by the Medium Resolution Imaging Spectrometer (MERIS) on ESA’s Envisat satellite in a series of image acquisitions from 24 July to 13 August 2002.  This image features a phytoplankton bloom in northern Atlantic waters near Newfoundland, Canada, acquired 10 August 2002 by the MEdium Resolution Imaging Spectrometer (MERIS) sensor in two different manners. The right hand image is a qualitative estimation of the fluorescence signal emitted by phytoplankton. Clouds and lands have been masked and appear black. The left hand image is the corresponding ‘true colour’ image. Phytoplankton absorbs energy from solar light in the blue spectral range. Part of this energy is re-emitted through fluorescence, in the red spectral range. The fluorescence signal seen on the right hand image is an excellent indicator of the presence of phytoplankton. MERIS has been specifically designed to observe these subtle variations in the waters of our planet. MERIS - a colourful focus  Small, single-celled phytoplankton play a key role in the marine food chain. They convert sunlight, carbon dioxide and nutrients into carbohydrates on which nearly all life in the ocean depends. In most parts of the Earth's ocean, phytoplankton concentration is extremely low. However, in “upwelling areas,” deep water is pumped up to the surface by strong winds, such as trade winds blowing parallel to the coast. This deep water is rich in nutrients and as this supplies phytoplankton with the nitrogen, phosphate and silicate they need for their growth, which supports the whole food chain. The most important fishing grounds can be found in these upwelling areas. When this upwelling process collapses, as for instance off the Peruvian coast during El Nino events, the ecosystem is dramatically disrupted. Climate change has an impact on the intensity and geographical position of upwelling areas, which, in turn, has important consequences to fishing industries and those who depend on them.
Technical Information:  The first MERIS observation captured the huge phytoplankton patch produced by the 'upwelling' mechanism along the west coast of Africa near Mauritania. The unprecedented resolution allows fine-scale structures to be detected. In such upwelling areas, northeast trade winds bring deep and nutrient-rich water to the surface, feeding phytoplankton. Changes in climate affect the intensity of the upwelling with important consequences for marine ecosystems, fisheries and local economies. One important task for MERIS is to provide overviews of the dynamics of upwelling areas and their primary production. This, in turn, could improve management of fish stocks within sustainable limits. Another important task for MERIS is to provide information on carbon fixation through photosynthesis within the global ocean for a better understanding of the carbon cycle.
Technical Information:  One of the first photos taken by Envisat, ESA's Earth observation satellite on 22 March 2002. MERIS has the capability to remote sense phytoplankton by observing their fluorescence. Phytoplankton pigments absorb light in short-wavelength radiation (blue) and partially reemit it at the fluorescence wavelength. This technique is of very high interest in coastal waters where turbidity makes chlorophyll retrieval more difficult than in the open ocean. This image is the very first attempt done to verify the capability of MERIS to detect fluorescence from space. It will take several months of intense field measurements to compare the satellite data to in situ measurements, to perfectly characterize the instrument and make sure high quality data are delivered to MERIS users. The first results are already fascinating and surprisingly rapid. Release date: 11 June 2004 |