Detection Of Algal Blooms Research Articles

The ABDMAP (Algal Bloom Detection, Monitoring and Prediction) Concerted Action

This paper describes the ABDMAP (Algal Bloom Detection, Monitoring And Prediction) project, which was a Concerted Action funded by the European Commission and carried out from April 1997 to March 1999. In the course of the project a number of workshops were held in various European countries. These workshops were devoted to various scientific aspects of algal blooms and, in particular, to the use of Earth observation (remote sensing) data for the study of such blooms. Great attention was given to the needs of users or potential users from the academic and research communities, from organizations with operational responsibilities for the introduction of legislation or for the monitoring of algal blooms. A state-of-the-art review of scientific knowledge and of applications of this knowledge was compiled and a number of actions were undertaken to widen the appreciation of the potential use of Earth observation (remote sensing) data for the study of algal blooms, including toxic algal blooms.

The detection and mapping of algal blooms from space

Algal blooms change the colour of water through absorption by pigments and scattering by cells and associated detrital material. This paper gives a brief introduction, primarily using ocean colour imagery, to the use of satellite Earth observation measurements in detecting and mapping algal blooms. Two examples, using Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) imagery, show blooms within northern European waters.

Algal bloom research using airborne remotely sensed data: Comparison of high spectral resolution and broad bandwidth CASI data with field measurements in the swan river in Western Australia

The Compact Airborne Spectrographic Imager (CASI) was flown over parts of the Swan River, Western Australia, in February 1993 to provide data to assess uses of remote sensing for detection and monitoring of algal blooms. It was flown in both spectral (288 bands x 39 lines) and spatial (14 bands x 512 lines) modes. Some biological, physical, spectral and chemical sampling of the water column were collected as close as possible to the flight times. Analysis of the CASI Spectral‐ and Spatial‐Mode data showed a relationship with some algal types, their concentrations and other co‐varing parameters. A small number of well chosen bands were sufficient to identify some of the water quality parameters in the Swan River. A synthesized comparison was made with the optimum spectral bands that could be used in a simple airborne digital video system. The relative advantages and applicability of this approach is discussed.

Optical detection and assessment of algal blooms

Concerns about harmful algal blooms (HABs) have grown in recent years. There is a pressing need for robust, quantitative, and cost‐effective methods to detect and characterize algal blooms. Critical applications of these methods include long‐term monitoring of coastal waters to indicate the degree to which present trends of HABs and human activities are linked, early warning systems to protect aquaculture sites and to signal the need for further investigations, and systems to characterize synoptically the distributions and physiological state of phytoplankton in an oceanographic context. Because phytoplankton strongly influence the fate of light in the ocean, optical methods are well suited for HAB applications. Passive optical systems can measure ocean color or the penetration of solar irradiance in surface waters; both properties can be related to the constituents of natural waters, including phytoplankton. The sensors measure radiometric quantities: consequently, rigorous calibration is possible and measurements can be compared between sites and over long periods of time. One passive optical system—a radiometer buoy—is shown to be useful for characterizing biological variability in surface waters over scales from minutes to months. A red tide was easily observed in measures of ocean color from the buoy; sensors for downwelling irradiance detected a subsurface bloom. Some optical instruments use artificial illumination to determine optical properties such as the coefficients of absorption and scattering. These measures can be made continuously in situ and effectively related to phytoplankton. Several types of fluorometers can be used to characterize the abundance, pigmentation, and physiological state of phytoplankton. All of these optical technologies should be useful for the study of HABs, but biological interpretations of many optical measurements need further testing.