BACKGROUND Deforestation is one of the most ubiquitous forms of land degradation worldwide. Although remote sensing and aerial photographs can supply valuable information on land/use cover changes, they may not regularly be available for some tropical coasts (e.g., Cameroon estuary) where cloud cover is frequent. With respect to mangroves, researchers are now employing local knowledge as an alt...

Viruses are recognized as the most abundant and dynamic biological entities in the marine and estuarine environment. However, studies on the dynamics and activity of viruses in transient estuarine systems are limited. This study examines temporal and spatial variations in viral abundance (VA) and viral activity across the salinity gradient in a monsoon-driven tropical estuarine system (Cochin e...

Bacterial growth efficiency (BGE) is a key factor in understanding bacterial influence on carbon flow in aquatic ecosystems. We report intra annual variability in BGE, and bacteria mediated carbon flow in the tropical Mandovi and Zuari estuaries (southwest India) and the adjoining coastal waters (Arabian Sea). BGE ranged from 3 to 61% and showed clear temporal variability with significantly (AN...

The geochemical condition of surface sediments in a tropical estuary and adjoining shelf region is presented for their elemental interactions using statistical methods. Principal component analysis separated two clusters comprising of (i) heavy metals possessing significant correlation with texture (organic carbon, clay and silt), which belong to sediments in the shelf region and (ii) heavy met...

Po is concentrated in most marine organisms by factors of 10-10 relative to seawater concentration and its accumulation varies from one tissue to another, according to the capacity to concentrate polonium (Carvalho, 1988). This radionuclide gives rise to almost 7% of the dose equivalent, through natural radiation intake (UNSC, 1988) and about 77% of daily intake comes from solid food, mainly se...

Monthly sampling campaigns were carried out between February 2010 and January 2011 to evaluate the spatial and temporal distribution of nutrients (ammonium, nitrite, nitrate, dissolved organic nitrogen, phosphate, dissolved organic phosphorus and silicate) and chlorophyll-a along a salinity gradient in the tropical Cachoeira River estuary, subject to the untreated effluents of a sewage treatmen...

This chapter discusses definitions and classification of estuaries. It presents both the classical and more flexible definitions of estuaries. Then it discusses separate classifications of estuaries based on water balance, geomorphology, water column stratification, and the stratification–circulation diagram – Hansen–Rattray approach and the Ekman–Kelvin numbers parameter space. The most widely...