Harmful Algal Blooms Monitored from Space in Chile

Sea Technology, Jul 2006

Chile is currently the world's largest producer of fanned salmon and has a burgeoning mussel culture industry that is supplying a growing world market.

However, the country's marine aquaculture sector is vulnerable to harmful algal blooms (HABs) that cause physical or biochemical damage to fish and shellfish.

Early detection of HABs allows fish fanners to make timely decisions in order to minimize the damage to aquaculture. To aid in this effort, a team led by Hatfield Consultants Ltd. (Vancouver, Canada), under the European Space Agency (ESA)-funded Chilean Aquaculture Project (CAP), has implemented an early warning service based on Earth observation (EO) data, which delivers forecasts of potential HABs to aquaculture companies via a customized Internet portal.

Just like plants on land, algae employ green-pigmented chlorophyll for photosynthesis. The chlorophyll collectively tints the color of the surrounding water, providing a means of detecting these tiny organisms from space with dedicated ocean color sensors onboard satellites.

The CAP project utilizes a combination of near-real-time EO data-such as chlorophyll-a pigment concentration, secchi transparency, suspended matter and sea surface temperature, derived from the medium-resolution imaging spectrometer onboard ESA's Envisat satellite and the moderate-resolution imaging spectroradiometer onboard the U.S. National Aeronautics and Space Administration's Aqua satellite-and in-situ water monitoring to watch the Southern Ocean off the coast of Chile. A hydrodynamic model, established and validated through the project, is also used to characterize the water circulation patterns in the major aquaculture area in southern Chile.