Quantitative aspects of inorganic nutrient fluxes in the Gazi Bay (Kenya): implications for coastal ecosystems.
Quantitative aspects of inorganic nutrient fluxes in the Gazi Bay (Kenya): implications for coastal ecosystems.
复制标题
加齐湾（肯尼亚）无机养分通量的定量方面：对沿海生态系统的影响。
DOI：
10.1016/s0025-326x(02)00176-5
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发表时间：
2002
影响因子：
5.8
通讯作者：
I. Jumba
中科院分区：
文献类型：
--
作者：
B. Mwashote;I. Jumba
利用底栖通量钟罩箱（横截面积0.066 m2，容积0.0132 m3）对加齐湾近岸沉积物中的NH 4+、NO2-、NO3-、PO 43-和Si（OH）4在红树林、海草和珊瑚礁群落生境中的通量进行了原位测定。其目标是：（1）确定底栖通量、河流流量和季节变化对海湾沃茨营养物收支的影响;（2）确定潮汐和空间变化对水柱中营养物负荷的影响;（3）确定营养物来源对海湾总群落生产的相对重要性。直接测量的通量范围分别为−270至+148 μmol NH 4 +-N/m2/h; −60至+63 μmol NO2−-N/m2/h; −79至+41 μmol NO3−-N/m2/h; −79至+75 μmol PO 43 −-P/m2/h和+30至+350 μmol Si（OH）4-Si/m2/h。据确定，底栖通量是溶解无机NH 4+，NO2−和Si（OH）4的主要来源，而河流来源是重要的NO3−和PO 43 −进入加齐湾沃茨。季节变化对PO 43-通量、N：Si比、河流营养盐排放、浮游生物生产力和重要环境因子（如盐度和温度）有明显影响。潮汐和空间变化没有显着的影响营养盐浓度和净通量的水柱。结果表明，底栖通量主要负责近岸沿海生态系统的营养动态，特别是在直接陆地输入没有显着贡献的营养收支。
Fluxes of dissolved inorganic nutrients: NH4+, NO2−, NO3−, PO43−and Si(OH)4from 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 m2and 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 μmol NH4+–N/m2/h; −60 to +63 μmol NO2−–N/m2/h; −79 to +41 μmol NO3−–N/m2/h; −79 to +75 μmol PO43−–P/m2/h and +30 to +350 μmol 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)4while fluvial sources are important for NO3−and PO43−into Gazi Bay waters. Seasonal variations had an appreciable effect on the PO43−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.