Find research datasets worth reusing

openCC (other)Jan 2026View details →

The Biomass and Plant Functional Traits of Leymus chinensis Affected by Genotypic Diversity and Soil Nitrogen Addition through a Two-year Experiment, Tianjin, China, 2021-2023

In order to investigate the effects of soil nitrogen addition on the genotypic diversity of Leymus chinensis, 12 genotypes of Leymus chinensis were used as plant material and a two-factor experimental design was carried out in this study. Factor one was genotypic diversity of L. chinensis, including three levels: mono-genotype (G1), three genotypes (G3), and six genotypes (G6). Factor two was the soil nitrogen addition level, which included four levels: no nitrogen addition (N0), 2.5 g N/(m²·a) nitrogen application (N2.5), 5 g N/(m²·a) nitrogen application (N5), and 10 g N/(m²·a) nitrogen application (N10). Each treatment had 12 combinations as replicates, and 12 genotypes of L. chinensis were used. The frequency of each genotype was standardized across all treatment levels of genotypic diversity × soil nitrogen addition. The experiment commenced in September 2021 and soil nitrogen was applied every 2 months. Plants were cultivated in the experimental field at Nankai University, but were moved to a greenhouse for overwintering from November to February each year. During the experiment, there were no stresses or disturbances such as shading, drought, or insect feeding; weeds were regularly removed.

openCC (other)Oct 2021View details →

SBC LTER: Reef: Long-term experiment: biomass of kelp forest species, ongoing since 2008 (Reformatted to the ecocomDP Design Pattern)

This data package is formatted as an ecocomDP (Ecological Community Data Pattern). For more information on ecocomDP see https://github.com/EDIorg/ecocomDP. This Level 1 data package was derived from the Level 0 data package found here: https://pasta.lternet.edu/package/metadata/eml/knb-lter-sbc/119/7. The abstract below was extracted from the Level 0 data package and is included for context: These data represent values of biomass density for more than 200 species of macroalgae, invertebrates and fish measured in fixed plots at five reefs as part of a long-term experiment designed to evaluate the effects of disturbance to giant kelp on the structure and productivity of the benthic community. Taxon-specific relationships between size and mass were applied to field measurements of species abundance to estimate biomass density of each species. The five reefs (Arroyo Quemado 34°28.048’N, 120°07.031’W; Carpinteria 34°23.474’N, 119°32.510’W; Isla Vista 34°23.275’N, 119°32.792’W; Mohawk 34°23.649’N, 119°43.762’W; and Naples 34° 25.342’N, 119° 57.102’W) ranged in depth from 5.8 m to 8.9 m (MLLW) and were chosen to represent a range of physical and biological characteristics known to influence subtidal macroalgal assemblages in the region. A common (but not always persistent) feature on these reefs was the presence of the giant kelp, which forms a dense canopy at the sea surface that suppresses recruitment and growth of understory algae below it. See Methods for more information. The primary research objective of the Santa Barbara Coastal LTER is to investigate the importance of land and ocean processes in structuring giant kelp (Macrocystis pyrifera ) forest ecosystems. As in many temperate regions, the shallow rocky reefs in the Santa Barbara Channel, California, are dominated by giant kelp forests. Because of their close proximity to shore, kelp forests are influenced by physical and biological processes occurring on land as well as in the open ocean. SBC LTER research foc

Mass per tiller, nitrogen concentration, stable isotope ratios for carbon and nitrogen from the 1980-82 Eriophorum vaginatum reciprocal transplant experiment along a latitudinal gradient in interior Alaska collected in July, 2011

In 1980-1982, six transplant gardens were established along a latitudinal gradient in interior Alaska from Eagle Creek, AK in the south to Prudhoe Bay, AK in the north. Three sites, Toolik Lake (TL), Sagwon (SAG), and Prudhoe Bay (PB) are north of the continental divide and the remaining three, Eagle Creek (EC), No Name Creek (NN), and Coldfoot (CF), are south of the continental divide. Each garden consisted of 10 individual Eriophorum vaginatum tussocks transplanted back to their home-site, as well as 10 individuals from each of the other transplant sites. The gardens were harvested in 2011. Important variables are garden name, source population, mass per tiller, nitrogen concentration, and stable isotope ratios for Carbon and Nitrogen.

openCC (other)Mar 2017View details →

Carbon and nitrogen isotopes and concentrations in terrestrial plants from a six-year (2006-2012) fertilization experiment at the Arctic LTER, Toolik Field Station, Alaska.

The data set describes stable carbon and nitrogen isotopes and carbon and nitrogen concentrations from an August 2012 pluck of a fertilization experiment begun in 2006. Fertilization was with nitrogen (N) and phosphorus (P). Fertilization levels included control, F2, F5, and F10, with F2 corresponding to yearly additions of 2 g/m2 N and 1 g/m2 P, F5 corresponding to yearly additions of 5 g/m2 N and 2.5 g/m2 P, and F10 corresponding to yearly additions of 10 g/m2 N and 5 g/m2 P. After harvest, plants were separated by species and then by tissue. Tissues were then dried, ground and analyzed for stable isotopes and concentrations at the University of New Hampshire stable isotope laboratory.

Point-frame measurments from a nitrogen (N), phosphorus (P) and N+P fertilization experiment at the 2007 Anaktuvuk River, Alaska, USA fire scar during the 2016-2019 growing seasons

This file contains point-frame measurements from a nitrogen (N), phosphorus (P) and N+P fertilization experiment established in the southern section of the 2007 Anaktuvuk River fire in 2016 at a severely burned site and an unburned site. Pin-vegetation contact was recorded using a 0.75 m2 frame with 41 evenly spaced pin-drop points. Data was collected once during the height of the growing season in 2016 (when fertilization began) 2017, 2018 and 2019. This data was used to measure the impact of fertilization and fire on community composition.

Leaf area index (LAI) recorded from a nitrogen (N), phosphorus (P) and N+P fertilization experiment at the 2007 Anaktuvuk River, Alaska, USA fire scar during the 2016-2019 growing seasons

This file contains leaf area index (LAI) measurements from an nitrogen (N), phosphorus (P) and N+P fertilization experiment established in the southern section of the 2007 Anaktuvuk River fire in 2016. LAI was recorded using a handheld plant canopy analyzer (LI-COR 2200C; LI-COR, Lincoln, NE, USA) Data spans 4 years from 2016 (when fertilization began) until 2019. Data was recorded once a year at the peak of each growing season.

openCC (other)Sep 2025View details →

Block summaries of biomass, carbon, nitrogen, and phosphorus allocation among tissue types, species, and plant functional types from Arctic LTER 1981 Moist Acidic Tussock (MAT81) long-term experiment harvests: 2000 and 2015, Toolik Lake Field Station, Alaska.

A complete accounting of biomass, C, N, and P allocation both among tissue types (leaves, stems, rhizomes, roots) and among species and plant functional types from Arctic LTER 1981 Moist Acidic Tussock (MAT81) long-term experiment’s untreated control plots and plots that were fertilized annually, harvested after 20 and 35 years, near Toolik Lake Field Station, Alaska. Data are gram per meter squared summarized by block.

openOpenNov 2024View details →

Aquatic biofilm autotrohic index, carbon dioxide flux, and environmental conditions for the APEX water table experiment 2021-2023

To better understand linkages between hydrology and ecosystem carbon flux in northern aquatic ecosystems, we evaluated the relationship between plant communities, biofilm development, and carbon dioxide (CO2) exchange following long-term changes in hydrology in an Alaskan fen. We quantified seasonal variation in biofilm composition and CO2 exchange in response to lowered and raised water-table position (relative to a control) during years with varying levels of background dissolved organic carbon (DOC). We then used nutrient-diffusing substrates to evaluate cause-effect relationships between changes in plant subsidies (i.e., leachates) and biofilm composition among water-table treatments. We found that background DOC concentration determined whether plant subsidies promoted net autotrophy or heterotrophy on nutrient diffusing substrates. In conditions where background DOC was <= 40 mg L-1, plant subsidies promoted an autotrophic biofilm. Conversely, when background DOC concentration was >= 50 mg L-1, plant subsidies promoted heterotrophy. Greater light attenuation associated with elevated levels of DOC may have overwhelmed the stimulatory effect of nutrients on autotrophic microbes by constraining photosynthesis while simultaneously allowing heterotrophs to outcompete autotrophs for available nutrients. At the ecosystem level, conditions that favored an autotrophic biofilm resulted in net CO2 uptake among all water-table treatments, whereas the site was a net source of CO2 to the atmosphere in conditions that supported greater heterotrophy. Taken together, these findings show that hydrologic history interacts with changes in dominant plant functional groups to alter biofilm composition, which has consequences for ecosystem CO2 exchange.

openCC0Dec 2023View details →

FAB 1: Forests and Biodiversity Experiment - High density diversity experiment: carbon budget data

This data represents changes in above and belowground C pools in young stands six years after the initiation of the Forests and Biodiversity experiment (FAB1) in 2013, consisting of high density plots of one, two, five, or 12 tree species planted in a common garden. Trees were planted to represent a range of native functional diversity, including needle-leaf conifer and broadleaf deciduous species as well as ectomycorrhizal and arbuscular mycorrhizal species. We quantified the effects of species richness, phylogenetic diversity, and functional diversity on aboveground C accumulation, as well as on soil C accumulation, fine root C, and soil aggregation. To assess the role of the microbial community in mediating these effects, we further compared changes in soil C pools to phospholipid fatty acids (PLFAs) profiles collected in 2016.

Physical and microbial processing of dissolved organic nitrogen (DON) (Salinity Experiment) along an oligotrophic marsh/mangrove/estuary ecotone (Taylor Slough and Florida Bay) for August 2003 in Everglades National Park (FCE), South Florida, USA

A better understanding of the biogeochemical cycling of nutrients entering Florida Bay is a key issue regarding the restoration of the Everglades. In addition to precipitation, the other major source of freshwater to Florida Bay is from Taylor Slough and the C-111 Basin in the northeast section of the Bay. While it is known that these areas deliver significant amounts of N to the Bay, a significant portion of this is in the form of dissolved organic N (DON). The sources, environmental fate and bioavailability to microorganisms of this DON are however, not known. Should this DON be readily available, any increased load as a function of restoration changes might have an impact on internal phytoplankton bloom dynamics. No significant flocculation or precipitation of DOM occurred with increase in salinity, meaning that terrestrial DOM does not get trapped in the sediments but stays in the water column where it subjected to photolysis and advective transport. Sunlight has a significant effect on the chemical characteristics of DOM. While the DOC levels did not change significantly during photo-exposure, the optical characteristics of the DOM were modified. The environmental implications of this are conflicting: photo-induced polymerization may stabilize the DOM by reducing its bioavailability while photolysis may make the DOM more labile. Overall, DON bioavailability was relatively low in this region. Even though the amount of DON loaded to the bay may be significant, the fraction of DON available for microbial cycling is much smaller. The amount of N supplied by recycling may be a significant portion of the total DIN pool. All this must be considered in context with the proposed CERP modifications to flows. As of the latest initial Comprehensive Everglades Restoration Project (CERP) update, the flows to Taylor Slough and C-111/Panhandle Basis are not predicted to change very much from base conditions. Therefore we do not expect any great increases in TN loading in this

Physical and microbial processing of dissolved organic nitrogen (DON) (Photodegradation Experiment) along an oligotrophic marsh/mangrove/estuary ecotone (Taylor Slough and Florida Bay) for August 2003 in Everglades National Park (FCE), South Florida, USA

Greenhouse experiment (FCE) in April and August 2001: Responses of neotropical mangrove saplings to the combined effect of hydroperiod and salinity/Biomass

A greenhouse experiment was performed for 13.5 months to evaluate the effect of salinity and hydroperiod on seedling growth rates of 2 mangrove species( Laguncularia racemosa and Rizhophora mangle). Data analyses are currently being performed.

Greenhouse mixed culture experiment from August 2002 to April 2003 (FCE): Evaluate the effect of salinity and hydroperiod on interspecific mangrove seedlings growth rate (mixed culture) / Morphometric variables

A greenhouse experiment (mixed culture experiment) was performed for 8 months to evaluate the effect of salinity and hydroperiod on seedling growth rates of 2 mangrove species( Laguncularia racemosa and Rizhophora mangle). Data analyses are currently being performed.

openCC (other)Feb 2022View details →

The dataset and model code pertinent to the Everglades Peat Elevation Model (EvPEM): The salinity and inundation mesocosm experiment in freshwater and brackish water sawgrass wetlands in Florida Coastal Everglades (2015-2017).

This is an assembled data and Everglades Peat Elevation Model (EvPEMv1.0) Stella code used to estimate and simulate net ecosystem carbon balance (NECB) and peat elevation change in response to saltwater intrusion and level of inundations. Data from several studies were combined for the estimation of NECB, model parameterization, and calibration (Wilson, 2018; Wilson et al., 2018, 2019; Charles et al., 2019; Servais et al., 2020). The reported data includes aboveground net primary productivity (ANPP), belowground net primary productivity (BNPP), peat elevation change, and decomposition rates that were collected from outdoor laboratory mesocosm experiments conducted at the Florida Bay Interagency Science Center in Key Largo, Florida during 2015-17. The plant-soil monoliths were obtained from a freshwater peat and a brackish water peat marsh located within the Florida Coastal Everglades and transported to the Key Largo facility for the experimental manipulations. In experiments focused on the brackish water marsh, three experiments were carried out reflecting the combined effect of salinity, inundation, and peat exposure to air. The brackish water experiments characterized submerged (SUB), exposed (EXP), and extended depth of exposure of peat surface (EXTEXP) conditions, as we varied water depth relative to the peat surface. Each experiment was subjected to two salinity manipulations: (1) ambient (~10 ppt) porewater salinity (AMB) and (2) elevated (~20 ppt) salinity (SALT). The experimental design included six (2 X 3) treatments: (1) submerged ambient salinity (AMB.SUB), (2) submerged elevated salinity (SALT.SUB.), (3) exposed ambient salinity (AMB.EXP), (4) exposed elevated salinity (SALT.EXP), (5) exposed with extended exposure/dry-down ambient salinity (AMB.EXTEXP), and (6) exposed with extended exposure/dry-down elevated salinity (SALT.EXTEXP). The water level was kept 4 cm above the peat surface for the brackish water SUB treatments. Exposure for the EXP treatment

Quarterly porewater salinity and conductivity measurements from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx) Project

openCustomJan 2020View details →

Mesocosm experiment on fresh marsh plant community responses to salinity pulses in 2014 and 2015

We established mesocosm communities using seven freshwater species (Zizaniopsis miliacea, Pontederia cordata, Persicaria hydropiperoides, Peltandra virginica, Ludwigia peploides, Sagittaria lancifolia and Eleocharis palustris) collected in the same freshwater marsh (31°20’16”N, 81°27’52”W) between Apr 19th and Apr 22nd, 2014, and the sediments were collected from a freshwater pond (31°23'54"N, 81°16'47"W) on Sapelo Island, GA at the same time. Our experimental unit was a plastic round swimming pool (h = 18 cm, r = 122 cm) filled to the top with homogenized sediments. Each unit consisted of 2 individuals of Zizaniopsis, Pontederia, Peltandra and Sagittaria, 5 – 8 Persicaria and Ludwigia separately. Eleocharis was mixed up with other species, so there were uneven numbers in each unit. From May 22 to August 19, 2014, the mesocosm communities were treated with three salinity levels (3, 5, and 10 psu: practical salinity units) and five exposure durations (5, 10, 15, 20 and 30 days per month), relative to a freshwater control (n=3 per treatment combination). Except for 30 days treatment which equals saline press treatment, plants were watered with daily freshwater after treated with saline water for 5, 10, 15 and 20 days. Different salinities were achieved by mixing tap water with sea water. We simulated tides during the treatment, by watering the plants every morning and then pumping out the excess water through a 6-in (15 cm) slotted well (constructed of PVC pipe) in the afternoon. From August 20, 2014 to June 30, 2015, all mesocosm communities were flushed with fresh tap water to recover.

openCC (other)May 2021View details →

Effect of salt water intrusion on the distribution of invertebrates in a GA tidal freshwater marshes from the GCE Seawater Addition Long-Term Experiment (SALTEx) project.

To characterize the effect of persistent and episodic salt water intrusion on the distribution of common freshwater marsh invertebrates, we monitored the density of adult and juvenile fiddler crabs and snails. Prior to the start of salt water addition treatments, we collected data on the distribution of crabs and snails in all 30 experimental plots (6 replicates of 5 treatments: pressed salt water addition, pulsed salt water addition, fresh water addition, procedural control structure, and control no structure). In each experimental plot, we counted the number of adult and juvenile fiddler crab burrows and snails visible on the marshs surface in a 50cm x 75cm plot (juvenile fiddler crabs were counted in only half of this area) that was positioned in the Northeastern corner of each experimental plot. Initial data was collected in March 2014. A Bentho Torch was used to measure the concentrations of cyanobacteria, diatoms, and green algae on the marsh surface in 2015 and 2016.

SALTEx soil oxidation-reduction (redox) potential measurements from the GCE LTER Seawater Addition Long-Term Experiment (SALTEx) between July 2016 and March 2017

SALTEx (Seawater Addition Long-Term Experiment) is a field experiment designed to simulate saltwater intrusion in a tidal freshwater wetland to predict how chronic (Press) and acute (Pulse) salinization will affect this and other tidal freshwater ecosystems. The SALTEx experiment was initiated in 2012 and consists of 31 field plots , each 2.5 m on a side. There are three treatments (Press, Pulse, and Fresh) and two types of controls (with and without sides), each consisting of six replicates. The Press treatment plots receive regular (4 times each week) additions of a mixture of seawater and fresh river water. Pulse plots receive the same mixture of seawater and river water during September and October, which is historically a time of low flow in the river when natural saltwater intrusion occurs. The Fresh treatment plots receive regular additions of fresh river water. Treatment water is added during low tide to facilitate its infiltration into the soil, and all plots are inundated by astronomical tides at high tide. Response measurements include porewater chemistry, specifically concentrations of chloride, sulfate, sulfide, dissolved organic carbon (DOC), ammonium-N, nitrate/nitrite-N, dissolved reactive phosphorus, total phosphorus, total nitrogen, organic nitrogen, carbon:nitrogen ratio, organic-carbon:organic-nitrogen ratio, and pH.

Continuous groundwater well temperature, salinity and water level measurements at the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx) site from May 2014 to February 2018

The Georgia Coastal Ecosystems LTER Seawater Addition Long-Term Experiment (SALTEx) is a large-scale field experiment designed to simulate saltwater intrusion in a tidal freshwater wetland to predict how chronic (Press) and acute (Pulse) salinization will affect this and other tidal freshwater ecosystems. In order to characterize groundwater salinity, temperature, and plot flooding following experimental manipulation, unvented water pressure, temperature and conductivity were continuously measured in a PVC groundwater well installed at the SALTEx site. Measurements were made at the bottom of the well using a submerged Schlumberger CTD-Diver logger every 15 minutes from 30-May-2014 to 14-Feb-2018. In February 2016 a second CTD-Diver was deployed near the top of the well. Data were downloaded from the loggers using Diver Office communication software, then imported into MATLAB for post-processing, quality control and documentation. Raw, unvented pressure readings were corrected for atmospheric pressure and sensor height from the bottom of the well to generate corrected pressure readings, then water level, salinity and density were calculated from the measured variables using UNESCO algorithms. These data were collected as part of the Georgia Coastal Ecosystems LTER SALTEx project (http://gce-lter.marsci.uga.edu/public/app/send_project_eml.asp?id=73), and will be updated annually.