Overnight Shark River Surveys from Shark River Slough, Everglades National Park (FCE), South Florida from October 2001 to March 2002

Estuarine mixing interfaces have been a focus of wetland ecologists for the last three decades and are of growing concern today. Particularly critical in Everglades restoration, water quality and the dynamics of nutrients and dissolved materials across seasons in the natural system are being defined. We measured diurnal and seasonal (wet and dry) variation in microbial, dissolved and total nutrients and total organic carbon along a riverine transect and for a diurnal cycle in October of 2001 and March of 2002. For the diurnal sampling we anchored a houseboat mid Shark River 100m up river of the mesohaline Florida Coastal Everglades Shark River LTER site and sampled the water for chemical, microbial, and physical parameters. At slack high and low tides we sampled 10 miles offshore then at three sites up the Shark River. TOC (mM) and salinity (ppt) were highly correlated (r2 .97) along the river transect across seasons and TOC derived from terrestrial input. Bacterial production ranged from 1.88 to 10.99 mg C l-1 d-1 and was greatest in the dry season and at the most freshwater sampling points. Combined examination of our 49 sampled parameters both from the diurnal sampling and river transect sampling showed that our position for sampling in the river was critical and that the mid river-estuarine productivity maxima occurred within Shark River in both the wet and dry season. These data suggest this oligotrophic estuarine-river system is highly sensitive to watershed and river fringe nutrient inputs and remineralization vectors within the river.近三十年来，河口混合界面（estuarine mixing interfaces）一直是湿地生态学家的研究热点，如今其受关注度更与日俱增。在大沼泽地（Everglades）生态修复工作中，该界面尤为关键：科研人员正明确自然系统内的水质、养分与溶解物质随季节变化的动态规律。本研究沿河流样带，针对2001年10月与2002年3月的昼夜周期，测定了微生物、溶解态及总养分与总有机碳（total organic carbon, TOC）的昼夜与季节（干湿季）变化。进行昼夜采样时，我们将住家船锚定在鲨鱼河（Shark River）中游，即距中盐度（mesohaline）佛罗里达海岸大沼泽地鲨鱼河长期生态研究站点（Long-Term Ecological Research, LTER）上游100米处，采集水体以测定化学、微生物与物理参数。在涨憩与落憩时刻，我们先在离岸10英里处采样，随后在鲨鱼河上游的三个点位开展采样工作。沿河流样带的全季节采样数据显示，总有机碳（TOC，单位：mM）与盐度（salinity，单位：ppt）呈高度相关（决定系数r²=0.97），且其来源为陆地输入。细菌生产力（bacterial production）介于1.88至10.99 mg C·L⁻¹·d⁻¹之间，且在旱季与淡水占比最高的采样点位达到峰值。对昼夜采样与河流样带采样所得的49项参数进行综合分析后发现，本研究在河流中的采样点位至关重要，且无论湿季还是旱季，河流-河口中部的生产力峰值均出现在鲨鱼河河段内。本研究数据表明，这一贫营养型河口-河流系统对流域与河岸带的养分输入，以及河流内部的再矿化作用传输路径极为敏感。