Relationship Between Salinity and Macroinvertebrates Distributions on a Barrier Island in Georgia
Abstract
Sapelo Island is one of Georgia’s barrier islands that is almost completely state owned and managed. The island is characterized by the presence of salt marshes and tidal drainages that support large macroinvertebrate biodiversity. One of the macroinvertebrate species that defines the southeastern coast and is prevalent on Sapelo Island are crayfish. The goal of this research was to study the distribution, presence and diversity of macroinvertebrates on Sapelo Island, Georgia, and compare this with different quality parameters of surface water and soil. Macroinvertebrates were collected using D-Nets following Georgia Adopt-A-Stream’s sampling protocols. A YSI multiparameter instrument and a LabQuest Pro were used in the field to measure physical and chemical water parameters (temperature, pH, dissolved oxygen, conductivity, total dissolved solids). Nitrate concentrations were measured using an ISE nitrate specific probe from Vernier LLC. Water and soil samples were collected and transported to the lab where salinity was analyzed. Data shows that the presence of macroinvertebrates was heavily influenced by the salinity concentration/ conductivity value and secondly by the nitrate concentration. There seems to be a correlation between areas with low conductivity and salinity and a larger diversity of macroinvertebrates. These preliminary results showed strong negative correlations between salinity and the presence of crayfish. Crayfish on Sapelo Island appear to prefer low salinity waters (fresh and brackish water), which also coincided with low nitrate concentrations. These results imply that as global temperatures rise and seawater floods barrier islands, there will be a loss of habitats for some of the species of macroinvertebrates.
Relationship Between Salinity and Macroinvertebrates Distributions on a Barrier Island in Georgia
Sapelo Island is one of Georgia’s barrier islands that is almost completely state owned and managed. The island is characterized by the presence of salt marshes and tidal drainages that support large macroinvertebrate biodiversity. One of the macroinvertebrate species that defines the southeastern coast and is prevalent on Sapelo Island are crayfish. The goal of this research was to study the distribution, presence and diversity of macroinvertebrates on Sapelo Island, Georgia, and compare this with different quality parameters of surface water and soil. Macroinvertebrates were collected using D-Nets following Georgia Adopt-A-Stream’s sampling protocols. A YSI multiparameter instrument and a LabQuest Pro were used in the field to measure physical and chemical water parameters (temperature, pH, dissolved oxygen, conductivity, total dissolved solids). Nitrate concentrations were measured using an ISE nitrate specific probe from Vernier LLC. Water and soil samples were collected and transported to the lab where salinity was analyzed. Data shows that the presence of macroinvertebrates was heavily influenced by the salinity concentration/ conductivity value and secondly by the nitrate concentration. There seems to be a correlation between areas with low conductivity and salinity and a larger diversity of macroinvertebrates. These preliminary results showed strong negative correlations between salinity and the presence of crayfish. Crayfish on Sapelo Island appear to prefer low salinity waters (fresh and brackish water), which also coincided with low nitrate concentrations. These results imply that as global temperatures rise and seawater floods barrier islands, there will be a loss of habitats for some of the species of macroinvertebrates.