An official website of the United States government
This dataset contains species abundance data of epilithic diatoms collected from the Upper Kuparuk River, Alaska (USA), spanning from 1997 to 2022. The dataset is part of a long-term study aimed at understanding the ecological impacts of phosphorus enrichment in Arctic freshwater ecosystems. Samples were collected annually from both phosphorus-fertilized and reference reaches of the river to assess the influence of nutrient enrichment on diatom community composition. The dataset includes detailed records of diatom species identified and their relative abundances in the phosphorus reach only. Analyses of this dataset using permutational multivariate analysis of variance (PERMANOVA) and Redundancy Analysis (RDA) revealed significant shifts in diatom communities attributable to phosphorus enrichment. Indicator Species Analysis identified key diatom species that are reliable indicators of phosphorus-enriched conditions. This dataset provides valuable insights into the long-term responses of diatom communities to nutrient enrichment and the ecological interactions with mosses that colonized the fertilized reach. It serves as an important resource for researchers studying nutrient dynamics, ecological monitoring, and the impacts of climate change on Arctic freshwater systems.
more »
« less
Diatom composition and environmental data from the Greater Everglades, Florida, USA (2013-2020)
{"Abstract":["Environmental and diatom data were collected from sites in the Big Cypress National Preserve (BICY) by the South Florida/Caribbean Inventory and Monitoring Network of the National Park Service and from sites in the Everglades Protection Area (EPA) as part of the Monitoring and Assessment Program of the Comprehensive Everglades Restoration Plan. Samples from years 2012, 2013, 2019, 2019, and 2020 are included in this dataset. Environmental data include drier variables that have been found to influence diatom assemblage composition in the greater Everglades ecosystem, including periphyton mat total phosphorus (a proxy for phosphorus in the environment), water column pH, water column conductivity, water depth, days since last dry, and hydroperiod. Diatom data include diatom species composition as percent relative abundances. Code included is pertinent to the methods described in "Robust species optima estimates from non-uniformly sampled environmental gradients" by Solomon et al. 2025, Journal of Paleolimnology."]}
more »
« less
- Award ID(s):
- 2025954
- PAR ID:
- 10643725
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Abundance-weighted averaging is a simple and common method for estimating taxon preferences (optima) for phosphorus (P) and other environmental drivers of freshwater-ecosystem health. These optima can then be used to develop transfer functions to infer current and/or past environmental conditions of aquatic ecosystems in water-quality assessments and/or paleolimnological studies. However, estimates of species’ environmental preferences are influenced by the sample distribution and length of environmental gradients, which can differ between datasets used to develop and apply a transfer function. Here, we introduce a subsampling method to ensure a uniform and comparable distribution of samples along a P gradient in two similar ecosystems: the Everglades Protection Areas (EPA) and Big Cypress National Preserve (BICY) in South Florida, USA. Diatom optima were estimated for both wetlands using weighted averaging of untransformed and log-transformed periphyton mat total phosphorus (mat TP) values from the original datasets. We compared these estimates to those derived from random subsets of the original datasets. These subsets, referred to as “SUD” datasets, were created to ensure a uniform distribution of mat TP values along the gradient (both untransformed and log-transformed). We found that diatom assemblages in BICY and EPA were similar, dominated by taxa indicating oligotrophic conditions, and strongly influenced by P gradients. However, the original BICY datasets contained more samples with elevated mat TP concentrations than the EPA datasets, introducing a mathematical bias and resulting in a higher abundance of taxa with high mat TP optima in BICY. The weighted averaged mat TP optima of BICY and EPA taxa were positively correlated across all four dataset types, with taxa optima of SUD datasets exhibiting higher correlations than in the original datasets. Equalizing the mat TP sample distribution in the two datasets confirmed consistent mat TP estimates for diatom taxa between the two wetland complexes and improved transfer-function performance. Our findings suggest that diatom environmental preferences may be more reliable across regional scales than previously suggested and support the application of models developed in one region to another nearby region if environmental gradient lengths are equalized and data distribution along gradients is uniform.more » « less
-
Environmental and periphyton data were collected from transects in the Biscayne Bay Coastal Wetlands (BBCW) during the wet and dry seasons of 2022 to investigate the rate of carbonate sediment production by periphyton. Environmental data include surface water metrics (pH, salinity, conductivity, and water depth) and soil depths. Periphyton data include nutrient, production, and diatom species composition in samples collected from artificial substrates (periphytometers) placed in the field. Data collection for this project is complete, although the South Florida Management District continues to monitor these transects for a larger ongoing BBCW project.more » « less
-
Water column nutrient concentrations and autotrophy in oligotrophic ecosystems are sensitive to eutrophication and other long-term environmental changes and disturbances. Disturbance can be defined as an event or process that changes the structure and response of an ecosystem to other environmental drivers. The role disturbance plays in regulating ecosystem functions is challenging because the effect of the disturbance can vary in magnitude, duration, and extent spatially and temporally. We measured changes in total nitrogen (TN), dissolved inorganic nutrient (DIN), total phosphorus (TP), soluble reactive phosphorus (SRP), total organic carbon (TOC), and chlorophyll-a (Chl-a) concentrations throughout the Everglades, Florida Bay, and the Florida Keys. This region has been subjected to a variety of natural and anthropogenic disturbances including tropical storms, fires, eutrophication, and rapid increases in water levels from sea-level rise and freshwater restoration. We hypothesized that the rate of change in water quality would be greatest in the coastal ecotone where disturbance frequencies and marine P concentrations are highest, and in freshwater marshes closest to hydrologic changes from restoration. We applied trend analyses on multi-decadal data (1996–2019) collected from 461 locations distributed from inland freshwater Everglades (ridge and slough) to outer marine reefs along the Florida Keys, USA. Total Organic Carbon decreased throughout the study area and was the only parameter with a systematic trend throughout the study area. All other parameters had spatially heterogeneous patterns in long-term trends. Results indicate more variability across a large spatial and temporal extent associated with changes in biogeochemical indicators and water quality conditions. Chemical and biological changes in oligotrophic ecosystems are important indicators of environmental change, and our regional ridge-to-reef assessment revealed ecosystem-specific responses to both long-term environmental changes and disturbance legacies.more » « less
-
This dataset contains species abundance data of epilithic diatoms collected from the Upper Kuparuk River, Alaska (USA), spanning from 1997 to 2022. The dataset is part of a long-term study aimed at understanding the ecological impacts of phosphorus enrichment in Arctic freshwater ecosystems. Samples were collected annually from the river to examine if physical, chemical, biological, weather, and climate variables influence diatom community composition over time. The dataset includes detailed records of diatom species identified and their relative abundances ins the reference reach only. Analyses of this dataset using permutational multivariate analysis of variance (PERMANOVA), canonical correspondence analysis (CCA), and partial canonical correspondence analysis (pCCA) . Analyses reveal significant shifts in diatom community composition over time, closely linked to changes in alkalinity, nitrate + nitrite, total dissolved phosphorus, dissolved organic carbon, and wind speed. We identify specific diatom taxa as bioindicators, highlighting their sensitivity to shifts in alkalinity, nitrate + nitrite, and wind speed. This dataset provides valuable insights on how climate change is reshaping the structure and function of Arctic rivers, underscoring the importance of diatoms as bioindicators in Arctic ecosystems. It serves as an important resource for researchers studying nutrient dynamics, ecological monitoring, and the impacts of climate change on Arctic freshwater systems.more » « less
