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Baseline soil chemistry data measurements from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx)

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. Soils were destructively sampled before the beginning of the experiment (March 2014) and after approximately 3 years of treatments (December 2016) and analyzed for bulk density, percent carbon, percent nitrogen, total phosphorus, available phosphorus, available nitrate, and available ammonium.

Soil surface temperature measurements from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx) Project

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. We are measuring soil surface temperature in the plots as one of the response variables for the SALTEx project.

Green algae, cyanobacteria and diatom concentrations from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx) Project

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. We are measuring the abundance of benthic algae with a BenthoTorch as one of the response variables for the SALTEx project.

Fall 2017 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in July and August 2017. Visual surveys were conducted along 8 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

Continuous soil temperature measurements at 10 cm depth from 3 month-long deployments in summer and winter within the Georgia Coastal Ecosystems Long Term Ecological Research (GCE-LTER) site in 2017 and 2018

To understand the influence of marsh elevation and flooding on soil temperature in Spartina alterniflora marsh, we measured soil temperature at 10 cm depth along two transects that spanned a marsh edge to interior gradient. We then associated those measurements with elevation, creek water height and vegetation characteristics. Soil temperature was logged every 15 min with a Hobo Onset Tidbit Pendant Temperature probe in Spartina alterniflora-dominated marsh near the Georgia Coastal Ecosystems Long Term Ecological Research (GCE-LTER) eddy covariance flux tower. Measurements were collected along two transects of approximately 250 m in length from 18 plots (transect 1) or 20 plots (transect 2) and over 3 sample deployments of approximately 1 month in length: 27 Jul – 31 Aug 2017 (transect 1), 8 Jan – 13 Feb 2018 (transect 1) and 23 Aug – 18 Sep 2018 (transect 2). Plot elevations along each transect were measured with a Trimble R6 RTK after probes were installed in the marsh. Creek water heights were estimated with the pressure transducer associated with the GCE-LTER eddy covariance flux tower data. Spartina alterniflora height forms were measured for each sample station during August as the mean of all stem heights within 0.25 m quadrants centered over each soil probe location. While these data are 24 hr soil temperature measurements, during all three deployments, we found that daily mean soil temperature was negatively correlated with marsh elevation on the marsh platform during low tide conditions, which represented the majority of the observations.

openCC (other)May 2021View details →

GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2018

A quadrat survey was conducted in October 2018 to measure the species and size distribution of plants at 3 sampling sites on the creekbank of the Altamaha River. The sites were chosen to capture the transition from Spartina alterniflora to Spartina cynosuroides (site SCSA) and the transition from Spartina cynosuroides to Zizaniopsis miliacea (sites ZSC1 and ZSC2). The quadrats were established as permanent plots in October 2012 by placing PVC stakes along the creekbank at each site. Plots were evenly spaced, but were not randomly located because the goal was to start with mixtures of vegetation in most of the plots, and vegetation was distributed in patches along the creekbanks. Therefore, these plots provide useful measures of vegetation change, but are not a random sample of the vegetation at the site. Plots will be replaced each year as necessary to replace any lost to disturbance. 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. 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.

openCC (other)Oct 2020View details →

Fall 2018 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in July 2018. Visual surveys were conducted along 8 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

Quarterly plant monitoring survey -- shoot height and flowering status and calculated biomass of plants in three GCE LTER permanent monitoring plots (7,8,9) and three Altamaha River plant transition sites (SCSA,ZSC1,ZSC2) following hurricane Irma from October 2017 through October 2018.

The biomass of plants surveyed in permanent plots at 3 GCE LTER sampling sites (7,8,9) and 3 Altamaha River plant transition sites (SCSA, ZSC1, ZSC2) following hurricane Irma from October 2017 through October 2018. October data are duplicates of data from the annual fall monitoring data sets but are included here for completeness. 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-IRMA-2002a). Biomass twas 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-1711a, and allometric relationships were based on GCE data sets PLT-GCEM-0211b and PLT-GCEM-0812a. NOTE: These relationships were measured in the fall and may not be valid at other seasons.

Quarterly disturbance observations to three GCE LTER permanent monitoring plots (7,8,9) and three Altamaha River plant transition sites (SCSA,ZSC1,ZSC2) following hurricane Irma from October 2017 through October 2018.

To access the effect of hurricane Irma on the GCE domain, yearly monitoring of species and size distribution of plants at three GCE LTER sampling sites (7, 8, 9) and three Altamaha plant transition sites (SCSA, ZSC1, ZSC2) was expanded to quarterly sampling between October 2017 and October 2018. We established permanent vegetation monitoring plots in creekbank and midmarsh at GCE sites 1-10 in 2000. A dedicated Juncus zone was later added at sites 10 and 9. We established creekbank permanent vegetation monitoring plots in three plant transition zones along the Altamaha River in 2012. When we recorded plant sizes, we also noted any disturbance to the plots. Plots were scored as normal (no visible disturbance), disturbed by wrack (wrack present in plots and stems dead or broken), disturbed by snails (>100 Littoraria per square meter and plant biomass low), disturbed by pigs (animal trail through the plot, this mostly happened at site 8 mid-marsh), initial slump (plot at the creekbank sliding into the creek based on movement of pvc poles or formation of a crevasse), and terminal slump (plot had slid far enough down that vegetation had drowned). Plots that experienced terminal slump or could not be found for any reason were scored as lost. Lost plots were replaced with a new plot in the same general area with the plot code incremented by 10. For example if plot 3 was lost, it was replaced by 13, and then in turn by 23. October data are duplicates of data from the annual fall monitoring data sets but are included here for completeness.

openCC (other)May 2021View details →

Fall 2019 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in August 2019. Visual surveys were conducted along 8 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

openCC (other)May 2021View details →

GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2019

A quadrat survey was conducted in October 2019 to measure the species and size distribution of plants at 3 sampling sites on the creekbank of the Altamaha River. The sites were chosen to capture the transition from Spartina alterniflora to Spartina cynosuroides (site SCSA) and the transition from Spartina cynosuroides to Zizaniopsis miliacea (sites ZSC1 and ZSC2). The quadrats were established as permanent plots in October 2012 by placing PVC stakes along the creekbank at each site. Plots were evenly spaced, but were not randomly located because the goal was to start with mixtures of vegetation in most of the plots, and vegetation was distributed in patches along the creekbanks. Therefore, these plots provide useful measures of vegetation change, but are not a random sample of the vegetation at the site. Plots will be replaced each year as necessary to replace any lost to disturbance. 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. 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 2000 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at GCE LTER sampling sites 1, 3, 4, 5, and 6

Grasshopper abundance and species diversity were investigated at five sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in August 2000. Visual surveys were conducted along 10 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

Fall 2002 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in August 2002. Visual surveys were conducted along 10 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

Fall 2005 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in August 2005. Visual surveys were conducted along 8 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

Marsh soil characteristics at nine GCE-LTER sampling sites in May 2001

Soil cores were collected from two tidal marsh locations at nine GCE-LTER sampling sites in May 2001. Bulk density and organic Carbon, total Nitrogen, total Phosphorous, Cesium-137 and Lead-210 content were measured in 15 2cm sections from each 30cm core. The sampling locations were chosen to represent three estuaries of the Georgia coast (USA) that vary in delivery of freshwater and sediment. This study was conducted to evaluate the effects of freshwater input on soil properties, accretion and accumulation.

Soil respiration and temperature measurements at 5 GCE-LTER sampling sites from June 2003 to March 2005

Soil temperature and respiration were measured in tidal marshes at five GCE-LTER sampling sites. The sites represent estuaries of the Georgia coast (USA) that vary in delivery of freshwater and sediment. Replicate measurements were taken from several locations at each site (levee, marsh plain, and marsh dieback) on seven dates between June 2003 and March 2005 to evaluate the effects of freshwater input on soil respiration over time.

Fall 2006 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in July-August 2006. Visual surveys were conducted along 8 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

Fall 2007 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in July-August 2007. Visual surveys were conducted along 8 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

Fall 2008 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in August 2008. Visual surveys were conducted along 8 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.

Fall 2009 grasshopper monitoring -- mid-marsh grasshopper abundance and species diversity at eight GCE LTER sampling sites

Grasshopper abundance and species diversity were investigated at eight sampling sites within the Georgia Coastal Ecosystems (GCE) LTER study area in August 2009. Visual surveys were conducted along 8 2m by 10m transects randomly allocated within the mid-marsh zone at each site. All grasshoppers observed within each transect were counted and identified to species, if possible. This survey was conducted as part of the GCE invertebrate monitoring program, and will be performed annually to assess long-term changes in relative species abundances across the GCE study area.