As a part of the European Union's ongoing research project entitled
LIFECO (Linking hydrographic Frontal activity to ECOsystem dynamics),
scientists are using real-time imagery from the Sea-viewing Wide
Field-of-view Sensor (SeaWiFS) to monitor the development of the spring
phytoplankton bloom in the North Sea and Skagerrak. These data are used
to in conjunction with ship-based measurements of the annual bloom.
In the course of monitoring the spring bloom of diatoms in the region,
scientists detected a second, harmful algal bloom (called Chattonella)
off the southern coast of Norway on March 19, 2001. This harmful algal
bloom appears to have been carried by currents westward from the Swedish
coast of the Kattegat to the Norwegian coast where it has already killed
more than 1,000 tons of salmon in fish farms during the past week.
Norway is the world's top producer of Atlantic salmon, yielding about
400,000 tons per year.
SeaWiFS, which flies aboard the OrbView-2 satellite, precisely measures
ocean color (even variations of color so slight our eyes cannot perceive
the difference), which enables scientist to accurately estimate the
concentrations of sediments, organic materials, or even phytoplankton at
the surface. In the latter case, to be more precise, SeaWiFS measures
the concentration of chlorophyll-a, the green pigment found in
In the false-color image above, red pixels represent the areas with the
greatest concentrations of chlorophyll-a (more than 10 milligrams per
cubic meter), yellows show high concentrations (about 3 mg/m3), greens
and turquoise pixels show intermediate values (0.3 to 1 mg/m3), and
blues and purples show where there is little or no abundance of
chlorophyll-a. Note the very high values along the southern coasts of
Sweden and Norway, extending westward into the North Sea.
It should also be noted that while SeaWiFS can accurately measure
chlorophyll-a concentrations, it cannot yet be used to distinguish between species of
phytoplankton. So, without the aid of surface-based measurements, it is
not possible to pinpoint which parts of the bloom in this image are the
harmful algal bloom and which are the benign bloom of diatoms.
Image provided by the SeaWiFS Project,
NASA/Goddard Space Flight Center, and ORBIMAGE.Note: All
SeaWiFS images and data presented or referred to in
this email message are for research and educational use only.
All commercial use of SeaWiFS data must be coordinated with