Saving the Rainforest of the Ocean
--Arindam Biswas
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most reefs grow best in warm, shallow, clear, sunny and agitated water. Sometimes called rainforests of the sea, shallow coral reefs form some of Earth's most diverse ecosystems. They are fragile, partly because they are sensitive to water conditions. There are uplifted reefs also and they form a kind of marine terrace found in intertropical regions as a result of biological activity, shoreline advance and accumulation of reef materials. The formation of these platforms is controlled by changes in environmental conditions and by tectonic activity during recent geological times. Changes in climatic conditions have led to eustatic sea-level oscillations and isostatic movements of the Earth's crust, especially with the changes between glacial and interglacial periods.
Source: Hello Travel
Topographic and hydrographic information are basic elements in studies of nearshore geomorphology, hydrology, and sedimentary processes. This information includes both longterm and short-term changes taking place along the coast; which includes beach profiles, and changes due to erosion (Klemas, 2009). Remote sensing from satellites is an efficient and cost-effective approach to carry out the study. While remote sensing cannot provide the level of detail and accuracy at a single point than a field survey, the statistical power for inferring large scale patterns benefits in having complete areal coverage. Remote sensing imagery in the visible wavelengths is commonly used to perform mapping on coral reefs, utilising multispectral and hyperspectral data, acquired by airborne or satellite-based sensors. Both spatial and spectral resolutions help discriminate various mapping objective, from geomorphic zones (e.g., fore reef, reef crest) to benthic community cover (e.g., coral on reef matrix, algae and coral on rubble).
Remote sensing covers many technologies, from satellites to airborne sensors, unmanned aerial systems, boat-based systems, and autonomous underwater vehicles. Using available remote sensing technologies for coral reef mapping, the extent of the reef can be studied routinely. Apart from mapping only, the rugosity, macroalgal matters, and bleached corals present in the colony can also be studied.
A fire coral before (left) and after (right) bleaching. (Source: Mongabay)
Remote sensing techniques are also used to identify the proxy for various environmental parameters, such as estimation of water attenuation as a proxy for water depth, turbidity for sedimentation, algal bloom for pollution, and sea surface temperature for thermal stress....... To read the full story click here.
