Monthly monitoring fluorescence data for Shark River Slough and Taylor Slough, Everglades National Park, Florida, USA (FCE LTER) for 2012 to Present
Authors: John Kominoski
Time period: 2012-01-01 to 2020-12-31
Package id: knb-lter-fce.1234.1
How to cite:
Kominoski, J.. 2021. Monthly monitoring fluorescence data for Shark River Slough and Taylor Slough, Everglades National Park, Florida, USA (FCE LTER) for 2012 to Present. Environmental Data Initiative. https://doi.org/10.6073/pasta/d1abed5732fe4f4b086e092fb85bf431. Dataset accessed 2022-12-05.
Dataset AbstractDissolved organic matter plays an important role in biogeochemical processes in aquatic environments such as elemental cycling, microbial loop energetics, and the transport of materials across landscapes. Since most of N (> 90%) and P (around 90%) is in the organic form in the oligotrophic subtropical Florida Coastal Everglades (FCE), study of the source and dynamics of dissolved organic matter (DOM) in the ecosystem is crucial for the better understanding of the biogeochemical cycling of nutrients. FCE are composed of estuaries with distinct regions with different biogeochemical processes. Freshwater marsh primarily receives terrestrial input and local autochthonous vegetation production. Mangrove ecotone, nevertheless, is affected by the tidal contributions from Florida Bay and local mangrove production. Florida Bay (FB) is a wedge-shaped shallow oligotrophic estuary which lays south of the Everglades, the bottom of which is covered with a dense biomass of seagrass. The sources of both freshwater and nutrients in FCE are difficult to quantify, owing to the non-point source nature of runoff from the Everglades and the dendritic cross channels in the mangroves. Furthermore, the combination of multiple DOM sources (freshwater marsh vegetation, mangroves, phytoplankton, seagrass, etc.), and the potential seasonal variability of their relative contribution, along with the history of (photo)chemical and microbial diagenetic processing, and complex advective circulation, makes the study of DOM dynamics in FCE particularly difficult using standard schemes of estuarine ecology. Quantitative information of DOM is very useful to investigate the biogeochemical cycling of DOM to a certain degree, however, qualitative information is necessary to better understand the source and dynamics of DOM. Since fluorescence spectroscopic techniques are very sensitive, quick and simple, they have been applied to investigate the fate of DOM in estuaries.
Geographic CoverageBounding Coordinates
N: 25.7463, S: 25.7463, E: -80.6537, W: -80.6537
N: 25.54973, S: 25.54973, E: -80.78520999999999, W: -80.78520999999999
N: 25.46821, S: 25.46821, E: -80.85328, W: -80.85328
N: 25.409760000000002, S: 25.409760000000002, E: -80.96431, W: -80.96431
N: 25.37702, S: 25.37702, E: -81.03235, W: -81.03235
N: 25.36463, S: 25.36463, E: -81.07795, W: -81.07795
N: 25.42389, S: 25.42389, E: -80.5903, W: -80.5903
N: 25.403570000000002, S: 25.403570000000002, E: -80.6069, W: -80.6069
N: 25.25241, S: 25.25241, E: -80.66272, W: -80.66272
N: 25.31472, S: 25.31472, E: -80.52209, W: -80.52209
N: 25.29479, S: 25.29479, E: -80.52024, W: -80.52024
N: 25.21418, S: 25.21418, E: -80.64908, W: -80.64908
N: 25.1908, S: 25.1908, E: -80.63911, W: -80.63911
N: 25.17693, S: 25.17693, E: -80.48978000000001, W: -80.48978000000001
N: 25.02477, S: 25.02477, E: -80.68097, W: -80.68097
N: 24.91293, S: 24.91293, E: -80.93798000000001, W: -80.93798000000001
Temporal CoverageStart Date: 2012
End Date: 2020
Water samples were collected monthly during February 2012 to December 2020 from a total of 14 sampling stations located in the coastal estuaries of the southern tip of the Florida Peninsula, USA. These stations were established for an on-going water quality monitoring program (http://www.serc.fiu.edu/wqmnetwork). Sampling stations can be largely grouped into 3 distinct districts based on the geomorphological features, that is, Florida Bay (FB, 3 sampling stations), Shark River Slough (SRS, 6 sampling stations), and Taylor Slough (TSPH, 8 sampling stations). Surface water samples were taken from the these stations. The samples were collected using pre-washed, brown Nalgen polyethylene bottles (Nalge Nunc International). Salinity of the water samples was measured in the field using an Orion salinity meter. The samples were stored on ice and returned to the laboratory within 8 h for analysis. Subsamples for spectroscopic analysis were filtered through precombusted Whatman GF/F glass fiber filters once received in the laboratory and analyzed immediately.
Total organic carbon (TOC) concentrations were analyzed by a high-temperature combustion method with a Shimadzu TOC-5000A TOC analyzer. In advance the analysis, samples were acidified with 3M HCl, and purged with N2 gas to remove inorganic C. Ancillary physical and chemical parameters were measured using standar methods as part of on-going estuarine water quality monitoring program http://www.serc.fiu.edu/wqmnetwork. Detailed methods will be found elsewhere. For escitation-emission matrix (EEM) measurements, fluorescences spectra were measured with a Jobin-Yvon-Horiba (France) Aqualog-2 fluorometer equipped with a 150-W continuous output xenon arc lamp under condition of 5.7-nm excitation and 2-nm emission slit widths and a 0.25 second response time. Forty-four emission scans were acquired at excitation wavelengths (lamda ex) between 240 and 455 nm at 5 nm intervals. Them emission wavelengths were scanned from lamda ex + 10 nm to lamda ex + 250 nm at 2 nm intervals (Coble et al., 1993 and Coble, 1996). All fluorescence spectra were acquired in ratio mode, whereby the sample (emission signal, S) and reference (excitation lamp output, R) signals were collected and the ratio (S/R) was calculated. The ratio mode eliminates the influence of possible fluctuation and wavelength dependency of excitation lamp output. Several post-acquisition steps were involved in the correction of the fluorescence spectra. First, an inner filter corrections was applied to the fluorescence data according to McKnight et al. (2001). After inner filter corrections the sample EEM underwent spectral subtraction of the Milli-Q water to remove most of the effects due to Raman scattering. Instrument bias related to wavelength dependent efficiencies of the specific instrument's optical components (gratings, mirrors, etc.) were then corrected by applying multiplication factors, supplied by the manufacturer, for both excitation and emission wavelengths for the range of observations. Finally, the fluorescence intensity values were converted to quinine sulfate unit (QSU;1QSU=1 ngL-1 of quinine sulfate monohydroxide) to facilitate inter-laboratory comparisons (Coble et al., 1993). From the 370 nm scan a fluorescence index (FI) was calculated (McKnight et al., 2001). The humification index (HIX) was quantified as the area under the emission curve between 435-480 nm divided by the area under the emission curve between 300-345 nm, for excitation at 254 nm (Zsolnay et al. 1999). The biological index (BIX), an indicator of the relative contribution of new autochthonous production to the DOM pool, was calculated as the emission at 380 nm divided by the emission at 430 nm, for excitation at 310 nm (Huguet et al. 2009). The slope ratio (SR), a measure of the average molecular weight, was calculated as the best-fir slope of the natural-log of abosorbance from 275 to 295 nm divided by the best-fit slope of the natural-log of absorbance from 350 to 400 nm (Helms et al. 2008). Milli-Q water was used as a reference for all fluorescence analysis. UV-visible measurements of the water samples were carried out with 1cm quartz UV-visible cells at room temperature (20 degrees C), using a Varian CARY 50 Bio UV-visible spectrophotometer. Milli-Q water was used as the reference.
Fluorescence measurements are corrected for internal absorbance quenching. Fluorescence spectra are corrected for internal instrument configuration using excitation and emission correction factors. For DOC, Humic carbon and carbohydrate data, we create calibration curves with standards and then graph the data.
==================== Data Sources =========================
Battin, T J 1998. Dissolved organic matter and its optical properties in a blackwater tributary of the upper Orinoco river, Venezuela. Organic Geochemistry, 28: 561-569.
Chen, Meilian L. 2010. Comparative study of dissolved organic matter from groundwater and surface water in the Florida costal Everglades using multi-dimensional spectrofluorometry combined with multivariate statistics. Applied Geochemistry, 25: 872-880.
De Souza Sierra, M M 1997. Spectral identification and behavior of dissolved organic fluorescence material during estuarine mixing processes. Marine Chemistry, 58: 51-58.
Donard, O F 1989. High-sensitivity fluorescence spectroscopy of Mediterranean waters using a conventional or a pulsed laser excitation source. Marine Chemistry, 27: 117-136.
Helms, John R. 2008. Absorption spectral slopes and slope ratios as indicators of molecular weight, source, and photobleaching of chromophoric dissolved organic matter. Limnology and Oceanography, 53(3): 955-969.
Huguet, A., Vacher, L., Relexans, S., Saubusse, S., Froidefond, J.M. and Parlanti, E., 2009. Properties of fluorescent dissolved organic matter in the Gironde Estuary. Organic Geochemistry, 40(6):706-719.
Lu, X Q 2003. Molecular characterization of dissolved organic matter in freshwater wetlands of the Florida Everglades. Water Research, 37: 2599-2606.
McKnight, Diane M 2001. Spectrofluorometric characterization of dissolved organic matter for indication of precursor organic material and aromaticity. Limnology and Oceanography, 46: 38-48.
Stedmon, Colin A. 2003. Tracing dissolved organic matter in aquatic environments using a new approach to fluorescence spectroscopy . Marine Chemistry, 82: 239-254.
Weishaar, James L. 2003. Evaluation of Specific Ultraviolet Absorbance as an Indicator of the Chemical Composition and Reactivity of Dissolved Organic Carbon . Environmental Science and Technology, 37: 4702-4708.
Yamashita, Youhei 2010. Dissolved organic matter characteristics across a subtropical wetland's landscape: Application of optical properties in the assessment of environmental dynamics. Ecosystems, 13: 1006-1019.
Zsolnay, A., Baigar, E., Jimenez, M., Steinweg, B. and Saccomandi, F., 1999. Differentiating with fluorescence spectroscopy the sources of dissolved organic matter in soils subjected to drying. Chemosphere, 38(1): 45-50.
Whatman 0.7um glass fiber filters, Shimadzu TOC-5000A Analyzer, Jobin Yvon Horiba (France) Aqualog-2 fluorometer, Varian CARY 50 Bio UV visible spectrophotometer
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Keywordsdisturbance, biogeochemistry, nutrients, sulfate, emissions, FCE, Florida Coastal Everglades LTER, ecological research, long-term monitoring, Everglades National Park, Dissolved organic matter, Taylor Slough, Shark River Slough, Fluorescence Index, Humification Index, Biological Index, Absorbance, Specific UV Absorbance, Fluorescence, Water, Dissolved organic carbon, estuaries, FCE LTER
Data Table and FormatData Table: Data from long term DOM study in Taylor and Shark Sloughs