Document Detail


Quantitative aspects of inorganic nutrient fluxes in the Gazi Bay (Kenya): implications for coastal ecosystems.
MedLine Citation:
PMID:  12523518     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Fluxes of dissolved inorganic nutrients: NH4+, NO2-, NO3-, PO4(3-) and Si(OH)4 from nearshore sediments of Gazi Bay were measured in situ within mangrove, seagrass and coral reef biotopes using benthic flux bell-jar chambers of cross-sectional area 0.066 m2 and volume 0.0132 m3. The objectives were: (1) to determine the influence of benthic fluxes, fluvial discharge and seasonal variations on the nutrient budget in the Bay waters; (2) to determine the effect of tidal and spatial variations on nutrient loads in the water column and (3) to establish the relative importance of the nutrient sources with regard to total community production of the Bay. The directly measured fluxes ranged from -270 to +148 micromol NH4+-N/m2/h; -60 to +63 micromol NO2(-)-N/m2/h; -79 to +41 micromol NO3(-)-N/m2/h; -79 to +75 micromol PO4(3-)-P/m2/h and +30 to +350 micromol Si(OH)4-Si/m2/h for and respectively. It was established that benthic fluxes are the major sources of dissolved inorganic NH4+, NO2- and Si(OH)4 while fluvial sources are important for NO3- and PO4(3-) into Gazi Bay waters. Seasonal variations had an appreciable effect on the PO4(3-) fluxes, N:Si ratio, river nutrient discharge, plankton productivity and important environmental factors such as salinity and temperature. Tidal and spatial variations had no significant effect on nutrient concentrations and net fluxes within the water column. The results imply that benthic fluxes are largely responsible for the nutrient dynamics of the nearshore coastal ecosystems especially where direct terrestrial inputs do not contribute significantly to the nutrient budget.
Authors:
Benjamin M Mwashote; Isaac O Jumba
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Marine pollution bulletin     Volume:  44     ISSN:  0025-326X     ISO Abbreviation:  Mar. Pollut. Bull.     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2003-01-13     Completed Date:  2003-05-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0260231     Medline TA:  Mar Pollut Bull     Country:  England    
Other Details:
Languages:  eng     Pagination:  1194-205     Citation Subset:  IM    
Affiliation:
Kenya Marine and Fisheries Research Institute, P. O. Box 81651 Mombasa, Kenya. bmwashote@recoscix.org
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MeSH Terms
Descriptor/Qualifier:
Ammonia / analysis
Ecosystem*
Environmental Monitoring
Geologic Sediments / chemistry*
Kenya
Nitrates / analysis
Nitrites / analysis
Nitrogen Compounds / analysis*
Oxygen / analysis
Phosphates / analysis*
Quaternary Ammonium Compounds / analysis
Seasons
Seawater / analysis*
Silicon Compounds / analysis
Sodium Chloride / analysis
Temperature
Water Movements
Chemical
Reg. No./Substance:
0/Nitrates; 0/Nitrites; 0/Nitrogen Compounds; 0/Phosphates; 0/Quaternary Ammonium Compounds; 0/Silicon Compounds; 7647-14-5/Sodium Chloride; 7664-41-7/Ammonia; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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