Variability in factors causing light attenuation in Lake Victoria
| Autor: | Luca Bracchini, Nicholas Azza, Andrés Cózar, Antonio Tognazzi, Claudio Rossi, Steven Loiselle, Arduino Massimo Dattilo |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
chemistry.chemical_classification
geography geography.geographical_feature_category Ecology Attenuation Drainage basin Aquatic Science Lake Victoria physical environment physical habitat modelling phytoplankton Oceanography Habitat chemistry Attenuation coefficient Dissolved organic carbon Phytoplankton Environmental science Organic matter Hydrobiology |
| Popis: | Summary 1. The major optical components controlling the attenuation of photosynthetic available radiation in nearshore areas of Lake Victoria (Uganda and Kenya) were examined and their impact compared. It was found that chromophoric dissolved organic matter and tripton play a dominating role in many nearshore areas, indicating that the coastal areas of Lake Victoria cannot be considered as Case I waters. 2. Concentrations of chromophoric dissolved organic matter declined with distance from the coast in an exponential manner indicating dilution and degradation of terrestrial sources of organic matter rather than in situ production. The importance of tripton was found to follow a similar pattern, while the relative importance of phytoplankton biomass in overall attenuation of photosynthetic available radiation was found to increase with distance from the coast. A specific attenuation coefficient for phytoplankton biomass was determined (0.019 m2 mg Chl a−1). 3. Using a light limitation approach based on carrying capacity, it was possible to map areas that are closer to being light limited. Light limitation appears to occur throughout most bays and some coastal areas receiving catchment waters. This spatial information, geographically referenced to bathymetric and catchment conditions, was utilized to understand the importance of environmental conditions in limiting phytoplankton biomass. |
| Databáze: | OpenAIRE |
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