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Survey of adult and juvenile periwinkle snail (Littoraria irrorata) density in mid-marsh and creekbank plots at GCE LTER study sites in October 2015.

To characterize spatial variation in the adult and juvenile density of periwinkle snails, Littoraria irrorata, within two zones in the salt marsh, the mid-marsh and creekbank, and across a gradient in salinity and distance to ocean, we surveyed snail density in October 2015. In each marsh zone at each GCE LTER permanent monitoring site, we counted the number of adult and juvenile snails in 8 replicate quadrats.

Survey of adult and juvenile periwinkle snail (Littoraria irrorata) density in mid-marsh and creekbank plots at GCE LTER study sites in October 2016.

To characterize spatial variation in the adult and juvenile density of periwinkle snails, Littoraria irrorata, within two zones in the salt marsh, the mid-marsh and creekbank, and across a gradient in salinity and distance to ocean, we surveyed snail density in October 2016. In each marsh zone at each GCE LTER permanent monitoring site, we counted the number of adult and juvenile snails in replicate quadrats (8 in creekbank and 12 in mid-marsh zones).

Survey of adult and juvenile periwinkle snail (Littoraria irrorata) density in mid-marsh and creekbank plots at GCE LTER study sites in October 2017.

To characterize spatial variation in the adult and juvenile density of periwinkle snails, Littoraria irrorata, within two zones in the salt marsh, the mid-marsh and creekbank, and across a gradient in salinity and distance to ocean, we surveyed snail density in October 2017. In each marsh zone at each GCE LTER permanent monitoring site, we counted the number of adult and juvenile snails in 8 replicate quadrats.

Variation in Landsat 8-estimated land surface temperature with elevation from Spartina alterniflora marsh cross sections in the Georgia Coastal Ecosystems Long Term Ecological Research (GCE-LTER) site and Virginia Coast Reserve (VCR) LTER sites for winter and summer observations spanning 2013-2018

We estimated land surface temperature from top of atmosphere brightness temperature provided by Landsat 8's band 10 (a thermal band). We collected these measurements first for Spartina alterniflora dominated marsh near the Georgia Coastal Ecosystems Long Term Ecological Research (GCE-LTER) eddy covariance flux tower. Measurements were collected from pixels along three east-west cross sections that spanned a marsh edge to interior gradient. We extracted Landsat 8 data for all available cloud-free low tide dates during August, September, January and February during the years 2013 to 2018 and associated these with marsh elevation information from a 1 m^2 Digital Elevation Model (DEM), created by Haldik et al 2013, also available from the GCE data catalog (http://dx.doi.org/10.6073/pasta/4c5187ef603f70cd0a77ece24ef0fed9). We rescaled the DEM to the coarser spatial resolution of Landsat 8 (30 x 30 m) where the rescaled elevation was the mean of the constituent DEM values. Ultimately, we used generalized additive models to relate land surface temperature to elevation, while accounting for variation from spatial proximity, transect and sample date. These models revealed that land surface temperature was negatively related to marsh elevation on the marsh platform. We then confirmed the generality of this pattern by rederiving these same relationships for three cross sections of Spartina alterniflora marsh at Virginia Coast Reserve (VCR) LTER for winter sampling dates only (data also included here). DEM data for VCR LTER are available at https://www.vcrlter.virginia.edu/gisdata/LIDAR/USGS2015/. We used custom R functions that can convert Landsat 8 top of atmosphere brightness temperature or top of atmosphere radiance from band 10 data to land surface temperature, which are available at https://github.com/jloconnell/convert_top_of_atmosphere_thermal_to_land_surface_temperature. Currently, a provisional land surface temperature product is available on earthexplorer.usgs.gov, w

Fall 2018 plant monitoring survey -- shoot height and flowering status of plants in permanent plots at GCE sampling sites 1-10

A quadrat survey was conducted in October 2018 to measure the species and size distribution of plants at 10 GCE LTER sampling sites. The quadrats were established as permanent plots at GCE sampling sites in October 2000 by placing wooden stakes at random locations across two nominal zones at each site, designated based on marsh structure (creekbank and high marsh). New plots were added each year as necessary to replace those lost due to catastrophic wrack disturbance or creek bank erosion. The plots were visually surveyed and the species, shoot height, and flowering status was recorded individually for each shoot over 10 cm in height present in each plot. Observations from plots exhibiting signs of disturbance were noted in a separate data set (PLT-GCEM-1801). This survey will be repeated annually to assess changes in plant distribution and biomass in relation to environmental changes documented by other GCE LTER monitoring efforts.

Fall 2018 plant monitoring survey -- biomass calculated from shoot height and flowering status of plants in permanent plots at GCE sampling sites 1-10

The biomass of plants surveyed in permanent plots at 10 GCE LTER sampling sites in October 2018 was estimated based on allometric relationships between biomass and shoot height and flowering status derived for each site, zone, and species in October 2002 and October 2008. Biomass was calculated for dominant species, including Spartina alterniflora, S. cynosuroides, Juncus roemerianus, and Zizaniopsis miliacea, as well as rarer species including Scirpus spp, Panicum spp. And Typha angustifolia. This data set is based on GCE plant monitoring survey data set PLT-GCEM-1811a, and allometric relationships were based on GCE data sets PLT-GCEM-0211b, PLT-GCEM-0711, and PLT-GCEM-2011.

Fall 2018 crab population monitoring: mid-marsh and creek bank abundance based on crab hole counts at GCE marsh, monitoring sites 1-10

This data set is the Fall 2018 estimate of crab densities at the GCE-LTER marsh sites used for population monitoring. Crab abundance was determined by counting the number of crab holes within a 625 cm^2 quadrat and converting the counts to number per square meter. Counts were made in the mid-marsh and creek bank zones (n = 4 per zone) at GCE sites 1 through 10. Note that this census method does not differentiate which species made a particular hole and therefore only estimates total burrowing crab abundance, potentially including species Uca pugnax, Uca minax, Uca pugilator, Armases cinereum, Eurytium limosum and Sesarma reticulatum. Crab holes that are not actively maintained are quickly covered by tidal activity and other sediment disturbances, therefore plugged holes were assumed to be unoccupied and excluded from the counts.

Mollusc population abundance monitoring: Fall 2018 mid-marsh and creekbank infaunal and epifaunal mollusc abundance based on collections from GCE marsh, monitoring sites 1-10

This data set is the Fall 2018 estimate of infaunal and epifaunal mollusc abundance at the GCE-LTER marsh sites used for population monitoring. Species abundance was determined by hand-collecting all the infaunal and epifaunal molluscs from within quadrats of known area in mid-marsh and creekbank zones (n = 4 quadrats per zone) at all sites. The molluscs were returned to the lab, fixed in ethanol, transferred to and preserved in ethanol, counted and measured (size data is reported separately). The counts were converted to number per square meter. Gastropod species are listed first, followed by bivalve species. Size distribution data for these collections may be found in the GCE-LTER data set INV-GCEM-1907a.

Mollusc population size distribution monitoring: Fall 2018 mid-marsh and creekbank infaunal and epifaunal mollusc size distributions based on collections from GCE marsh monitoring sites 1-10

This data set is the Fall 2018 report of infaunal and epifaunal mollusc species size distributions at the GCE-LTER marsh sites used for population monitoring. Infaunal and epifaunal molluscs were hand-collected from within quadrats of known area from mid-marsh and creekbank zones (n = 4 quadrats per zone) at all sites. The molluscs were returned to the lab, preserved in ethanol, measured and counted (count data is reported separately). Length of each measurable individual was determined using calipers or an ocular micrometer mounted in a stereomicroscope. Species abundance and density data for these collections may be found in the GCE-LTER data set INV-GCEM-1907. Numbers of individuals of each species in the abundance data file may not correspond exactly to the numbers of individuals in the size data file because some individuals may not have been measureable.

Survey of adult and juvenile periwinkle snail (Littoraria irrorata) density in mid-marsh and creekbank plots at GCE LTER study sites in October 2018.

To characterize spatial variation in the adult and juvenile density of periwinkle snails, Littoraria irrorata, within two zones in the salt marsh, the mid-marsh and creekbank, and across a gradient in salinity and distance to ocean, we surveyed snail density in October 2018. In each marsh zone at each GCE LTER permanent monitoring site, we counted the number of adult and juvenile snails in 8 replicate quadrats.

openCustomJan 2020View details →

Porewater measurements of dissolved nutrients (ammonia, nitrate/nitrite, phosphate) from core monitoring sites in the GCE-LTER domain following hurricane Irma from October 2017 to October 2018.

To access the effect of hurricane Irma on the GCE domain, porewater samples were collected to evaluate porewater nutrient concentrations at four core GCE monitoring sites (7, 8, 9 and 11). A limited number of samples were collected in October 2017 (a month after the storm surge from hurricane Irma hit the east coast of the United States) and then all sites were sampled in Nov 2017 and in Jan, Feb, Apr and Oct 2018. Porewater samples were obtained from approximately 10 cm depth using Rhizon samplers and then analyzed for ammonium, nitrate + nitrite, and phosphate concentrations.

Fall 2019 plant monitoring survey -- shoot height and flowering status of plants in permanent plots at GCE sampling sites 1-10

A quadrat survey was conducted in October 2019 to measure the species and size distribution of plants at 10 GCE LTER sampling sites. The quadrats were established as permanent plots at GCE sampling sites in October 2000 by placing wooden stakes at random locations across two nominal zones at each site, designated based on marsh structure (creekbank and high marsh). New plots were added each year as necessary to replace those lost due to catastrophic wrack disturbance or creek bank erosion. The plots were visually surveyed and the species, shoot height, and flowering status was recorded individually for each shoot over 10 cm in height present in each plot. Observations from plots exhibiting signs of disturbance were noted in a separate data set (PLT-GCEM-1801). This survey will be repeated annually to assess changes in plant distribution and biomass in relation to environmental changes documented by other GCE LTER monitoring efforts.

Fall 2019 plant monitoring survey -- biomass calculated from shoot height and flowering status of plants in permanent plots at GCE sampling sites 1-10

The biomass of plants surveyed in permanent plots at 10 GCE LTER sampling sites in October 2019 was estimated based on allometric relationships between biomass and shoot height and flowering status derived for each site, zone, and species in October 2002 and October 2008. Biomass was calculated for dominant species, including Spartina alterniflora, S. cynosuroides, Juncus roemerianus, and Zizaniopsis miliacea, as well as rarer species including Scirpus spp, Panicum spp. And Typha angustifolia. This data set is based on GCE plant monitoring survey data set PLT-GCEM-1911a, and allometric relationships were based on GCE data sets PLT-GCEM-0211b, PLT-GCEM-0711, and PLT-GCEM-2011.

Fall 2019 crab population monitoring: mid-marsh and creek bank abundance based on crab hole counts at GCE marsh, monitoring sites 1-10

This data set is the Fall 2019 estimate of crab densities at the GCE-LTER marsh sites used for population monitoring. Crab abundance was determined by counting the number of crab holes within a 625 cm^2 quadrat and converting the counts to number per square meter. Counts were made in the mid-marsh and creek bank zones (n = 4 per zone) at GCE sites 1 through 10. Note that this census method does not differentiate which species made a particular hole and therefore only estimates total burrowing crab abundance, potentially including species Uca pugnax, Uca minax, Uca pugilator, Armases cinereum, Eurytium limosum and Sesarma reticulatum. Crab holes that are not actively maintained are quickly covered by tidal activity and other sediment disturbances, therefore plugged holes were assumed to be unoccupied and excluded from the counts.

Mollusc population abundance monitoring: Fall 2019 mid-marsh and creekbank infaunal and epifaunal mollusc abundance based on collections from GCE marsh, monitoring sites 1-10

This data set is the Fall 2019 estimate of infaunal and epifaunal mollusc abundance at the GCE-LTER marsh sites used for population monitoring. Species abundance was determined by hand-collecting all the infaunal and epifaunal molluscs from within quadrats of known area in mid-marsh and creekbank zones (n = 4 quadrats per zone) at all sites. The molluscs were returned to the lab, fixed in ethanol, transferred to and preserved in ethanol, counted and measured (size data is reported separately). The counts were converted to number per square meter. Gastropod species are listed first, followed by bivalve species. Size distribution data for these collections may be found in the GCE-LTER data set INV-GCEM-2007a.

Mollusc population size distribution monitoring: Fall 2019 mid-marsh and creekbank infaunal and epifaunal mollusc size distributions based on collections from GCE marsh monitoring sites 1-10

This data set is the Fall 2019 report of infaunal and epifaunal mollusc species size distributions at the GCE-LTER marsh sites used for population monitoring. Infaunal and epifaunal molluscs were hand-collected from within quadrats of known area from mid-marsh and creekbank zones (n = 4 quadrats per zone) at all sites. The molluscs were returned to the lab, preserved in ethanol, measured and counted (count data is reported separately). Length of each measurable individual was determined using calipers or an ocular micrometer mounted in a stereomicroscope. Species abundance and density data for these collections may be found in the GCE-LTER data set INV-GCEM-2007. Numbers of individuals of each species in the abundance data file may not correspond exactly to the numbers of individuals in the size data file because some individuals may not have been measureable.

Survey of adult and juvenile periwinkle snail (Littoraria irrorata) density in mid-marsh and creekbank plots at GCE LTER study sites in October 2019.

To characterize spatial variation in the adult and juvenile density of periwinkle snails, Littoraria irrorata, within two zones in the salt marsh, the mid-marsh and creekbank, and across a gradient in salinity and distance to ocean, we surveyed snail density in October 2019. In each marsh zone at each GCE LTER permanent monitoring site, we counted the number of adult and juvenile snails in 8 creekbank and 12 mid-marsh replicate quadrats.

openCC (other)Apr 2021View details →

Eddy covariance 30-minute CO2 fluxes with accompanying biophysical variables from the Grand Bay, Mississippi flux tower site from March 2018 to January 2019

Eddy covariance (EC) CO2 fluxes from March 2018 to January 2019 collected over a Juncus roemerianus marsh located in the Grand Bay National Estuarine Research Reserve (NERR) in Mississippi. EC fluxes were processed in EddyPro 7. Additional biophysical variables included are air temperature, relative humidity, vapor pressure deficit, soil temperature, and water table height within the marsh.

openCC (other)Apr 2021View details →

Eddy covariance 30-minute CO2 fluxes with accompanying biophysical variables from the GCE-LTER flux tower site from December 2018 to January 2020

Eddy covariance (EC) CO2 fluxes from December 2018 to January 2020 collected over a Spartina alterniflora marsh located on the western side of Sapelo Island bounded by the Duplin River and Barn Creek. EC fluxes were processed in EddyPro 7. Additional biophysical variables included are air temperature, relative humidity, vapor pressure deficit, soil temperature, and water table height from a nearby tidal creek.

Survey of adult and juvenile periwinkle snail (Littoraria irrorata) density in mid-marsh and creekbank plots at GCE LTER study sites in October 2020.

To characterize spatial variation in the adult and juvenile density of periwinkle snails, Littoraria irrorata, within two zones in the salt marsh, the mid-marsh and creekbank, and across a gradient in salinity and distance to ocean, we surveyed snail density in October 2020. In each marsh zone at each GCE LTER permanent monitoring site, we counted the number of adult and juvenile snails in 8 creekbank and 12 mid-marsh replicate quadrats.