Florida Coastal Everglades Long Term Ecological Research
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PAST WORKING GROUPS

Nutrients and DOM Working Group
(Phase I, 2000-2006)


Abstract:
The Nutrients and DOM Working Group is mandated to 1) provide baseline data for other FCE-LTER researchers, 2) develop functional relationships between hydrology and nutrient loading and transformations, and 3) investigate the coupling between physically and biotic aspects of DOM and nutrient cycling.

Autosampler in Taylor Slough (TS/Ph-3) Autosampler in Taylor Slough (TS/Ph-3). We use autosamplers to collect water quality samples at our wetland sites.


Water Quality: Water quality samples are being collected using ISCO autosamplers at all wetland sites (that is, all sites except TS/Ph-9, 10, and 11). Water is sampled once every 3 days. The samples are collected every 3-4 weeks and analyzed for total phosphorus (TP), total nitrogen (TN), and salinity. When sites are visited to collect these samples, a grab sample is also collected and immediately put on ice. A portion of these grab samples is analyzed for dissolved nutrients (NO2-, NO3-, NH4+, SRP, and DOC). The unfiltered fraction of these grab samples is analyzed for TP, TN, and TOC. These monthly grab samples are used to generate relationships between TP and SRP, and between TN and NO2- + NO3- + NH4+. In addition to the regular water quality monitoring, the rain level actuators at all freshwater sites are used to trigger water sampling after rain events exceed a given threshold of duration and/or intensity. Rain event samples are collected, treated, and analyzed as all other water quality samples. Investigators collaborate with a separately funded monitoring program (funded by SFWMD and EPA to J.Boyer; http://serc.fiu.edu/wqmnetwork) to obtain water quality for the 3 Florida Bay sites (TS/Ph-9, 10, and 11). This monitoring program provides monthly sampling of temperature, salinity, DO, NH4+, NO3-, NO2-, TN, TON, SRP, TP, TOC, chlorophyll a, alkaline phosphatase activity, turbidity, and light extinction at these 3 sites.


Microbial Loop Parameters: This study provides a means to concurrently analyze the contribution of microbial community to nutrient and dissolved organic carbon pools. Monthly sampling events of Florida Bay, Whitewater Bay, and coastal Everglades sites for microbial parameters were conducted beginning in 2001. Algal energetics (as quantum yield) and chlorophyll a concentrations for major phytoplankton guilds (green algae, brown algae, and cyanobacteria) are quantified using pulse amplitude modulated fluorometry. Bacteria are quantified by direct counts using the molecular marker SYBR Green I; 3H-thymidine uptake is used to measure bacterial production.


Shark River Surveys: Biannual sampling events of the Shark River estuary in the Everglades are performed beginning in 2001. Surveys are conducted at slack low and high tide along the salinity gradient. In addition samples are collected at a central station in the river over a 48 hour period. Variables measured include temperature, salinity, dissolved oxygen, ammonium, nitrate, nitrite, total nitrogen, total organic nitrogen, soluble reactive phosphorus, total phosphorus, total organic carbon, chlorophyll a, alkaline phosphatase activity, turbidity, and light extinction. Algal energetics (as quantum yield) and chlorophyll a concentrations for major phytoplankton guilds (green algae, brown algae, and cyanobacteria) were quantified using pulse amplitude modulated fluorometry. Bacteria are quantified by direct counts using the molecular marker SYBR Green I; 3H-thymidine uptake is used to measure bacterial production.


Dissolved Organic Matter Characterization and Quantification: Dissolved organic matter (DOM) from different locations within the Florida Coastal Everglades is being quantified and its' molecular nature characterized by a variety of chemical methods. DOM in water samples collected from over 60 estuarine sites on a monthly basis are characterized by fluorescence techniques such as emission fluorescence and synchronous fluorescence with the objective to better understand DOM dynamics (i.e. origin, fate and transformations) in the system. In addition, biannual sampling events of the Shark River and Taylor River estuary in the Everglades are performed beginning in 2001. Surveys of DOM fluorescence characteristics are conducted at slack low and high tide along the salinity gradient and correlated with other water quality parameters as described above. In addition samples are collected at a central station in the river over a 48 hour period. During the Fall 2001 period DOM samples from these transects will also be concentrated through ultrafiltration and the high molecular weight fraction (1000 daltons - 0.2 µm) characterized by more advanced techniques such as 13C-NMR, FTIR and pyrolysis-GC/MS. These analyses were performed at all FCE-LTER sites biannually starting in Spring 2002.
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National Science Foundation logo This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DEB-1237517, #DBI-0620409, and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
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