Microbial Sampling from Shark River Slough and Taylor Slough, Everglades National Park, South Florida (FCE) from January 2001 to Present

We collected monthly observations of water microbial characteristics from each of the FCE LTER sites beginning in February 2001. Bacteria counts using DAPI epifluorescence, heterotrophic bacteria production with tritiated Thymidine uptake, and algal energetics and chl a using the PAM fluorometer were determined from each of the water samples. Bacteria counts in Shark River Slough in the freshwater end of the transect revealed highest bacteria numbers upon marsh rewetting after the dry down. The highest overall count of bacteria was found at the most freshwater point adjacent to the perimeter of the water conservation area but only in March of 2001. Peak numbers of bacteria in the saline end of Shark River transect occurred in December and July. There is some evidence that these higher bacteria numbers in the SR transect are associated with higher salinities. Highest bacteria counts along the Taylor slough transect were observed at the mouth of the Taylor River with peak counts in the wet season in October. Bacteria densities also increased from the eastern to western end of the transect in Florida Bay. Heterotrophic bacterial production did not relate closely bacteria numbers and exhibited highest numbers in the dry season. There was no discernible relationship between salinity and bacteria production as seen in bacteria numbers. Monthly observations using PAM fluorometry revealed that brown algae was the greatest contribution to the algal chal a pool and this relationship was consistent across all FCE LTER sites. Converse to the pattern of bacteria abundance along the Shark River transect, there was evidence that algal biomass decreases from freshwater to estuary. In the Shark River, algal energetics increased from marsh to estuary as well as in the panhandle region of the Taylor River transect. From these observations we conclude the behavior of the microbial loop and interactions generated between functional guilds is highly variable along individual transects and between the Shark River and Taylor River transect. Wet dry season dynamics partially explain temporal variability in microbial dynamics along the individual transects yet responses were unique for each section of the transect as freshwater versus estuarine versus Bay. Relationships between salinity and microbial parameters in this case, were not easily discerned but were more consistent within the two river transects than between river transects.本数据集于2001年2月起，对佛罗里达海岸大沼泽地长期生态研究站点（FCE LTER）的各监测点位开展水体微生物特征的月度观测。所有水体样本均完成以下检测：采用DAPI荧光显微计数法测定细菌总量，利用氚标记胸苷摄取法测算异养细菌生产力，借助脉冲振幅调制荧光仪（PAM fluorometer）分析藻类能量代谢与叶绿素a（chl a）含量。 对样带淡水端的鲨鱼河沼泽开展细菌计数结果显示，干旱期结束后的沼泽复淹阶段，细菌数量达到峰值。全数据集内细菌总量的最高值出现在紧邻水源保护区边界的最淡水点位，但仅在2001年3月观测到该峰值。鲨鱼河样带咸水端的细菌数量峰值分别出现在12月与7月。有证据表明，鲨鱼河样带（SR transect）内的细菌丰度升高与盐度升高存在相关性。 泰勒沼泽样带的细菌总量最高值出现在泰勒河河口，且峰值对应10月的湿季。佛罗里达湾样带的细菌密度同样呈现从样带东端向西端逐步升高的趋势。异养细菌生产力与细菌总量并无显著关联，其峰值出现在旱季；与细菌总量的盐度响应规律不同，盐度与异养细菌生产力之间未呈现可辨识的相关性。 通过脉冲振幅调制荧光仪开展的月度观测显示，褐藻对藻类叶绿素a库的贡献占比最高，且该特征在所有FCE LTER站点中均保持一致。与鲨鱼河样带的细菌丰度分布规律相反，有证据表明藻类生物量从淡水区域向河口湾逐步降低。在鲨鱼河区域，藻类能量代谢从沼泽到河口湾呈升高趋势；泰勒河样带的狭长地带区域亦呈现该规律。 基于上述观测结果，本研究得出结论：微生物食物环的动态变化以及功能群间的相互作用，在各单一样带内部以及鲨鱼河与泰勒河样带之间均存在显著异质性。干湿季的动态变化可部分解释单一样带内微生物动态的时间变异性，但样带不同区段（淡水区、河口湾区与海湾区）的响应特征各具特异性。本数据集内盐度与微生物参数之间的关联并不易于辨识，但相较于两条河流样带之间，该关联在单条河流样带内部的一致性更强。