Spatial variation of nutrients and primary productivity in the Rufiji Delta mangroves,Tanzania |
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| Authors: | A Minu JF Machiwa S Pamba |
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| Institution: | 1. Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, Dar es Salaam, Tanzania  https://orcid.org/0000-0002-5214-0692;2. Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, Dar es Salaam, Tanzania;3. Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, Dar es Salaam, Tanzania https://orcid.org/0000-0003-2299-2541 |
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| Abstract: | Determinations of spatial and temporal variations in organic matter and nutrient dynamics in water and sediments are crucial for understanding changes in aquatic bodies. In this study, we (i) determine the spatial dynamics of dissolved inorganic nutrients, during the transition from the dry to the rainy season, and (ii) provide future productivity predictions for the Rufiji Delta mangroves, Tanzania, based on the input of various nutrients. Water samples were collected from six locations, three times per year between April 2012 and January 2014, and analysed for dissolved nutrients, total organic and inorganic carbon, chlorophyll a, chlorophyll b and total carotenoids. The prediction of future net primary productivity in the Rufiji mangroves was undertaken using the software STELLA. The mean nutrient concentrations were of the order: nitrate > phosphate > ammonium > silica > dissolved organic carbon. The study revealed that high nutrient concentrations occurred in the northern part of the Rufiji Delta as a result of anthropogenic influence in the watershed. Modelling of nutrient inputs into the delta indicated enhanced primary productivity, which is expected to increase the vulnerability of water quality in the near future due to eutrophication. |
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| Keywords: | biogeochemical processes chlorophyll estuary modelling N:P ratios nutrient input plant pigments water quality |
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https://orcid.org/0000-0002-5214-0692;2. Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, Dar es Salaam, Tanzania;3. Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, Dar es Salaam, Tanzania