Category Archives: geology

New survey vessel joins the fleet

The Alexander lab is in the process of configuring a new shallow water survey boat to enhance their capabilities for collecting high-resolution bathymetric data. new-boat-1-w Hydrographic surveys in shallow environments present challenging logistical situations.  The new hydrographic survey launch will greatly extend the range of tides and conditions available for survey missions.  The launch is 10 ft long and will be equipped with a Knudsen Mini-Sounder single-beam sonar, a dual head GNSS GPS system, an inertial motion sensor, and a waterproof touchscreen computer.


Alexander lab busy on the coast

The Clark Alexander lab is busy mapping the bathymetry and benthic habitats of Ossabaw Sound and will be starting to map Sapelo Sound this fall, with funding from Ga. Department of Natural Resources.

Clark anticipates more work examining shoreline change at Ft. Pulaski and other islands in the Savannah River to better understand current erosional patterns before the ongoing harbor deepening is completed. That project would be funded by the National Park Service and Ga. Department of Transportation.

The ongoing assessment of sand resources in Federal waters will get a boost, as new funding has been made available through the Bureau of Ocean Energy Management. The work will be to fill data gaps identified in the first round of studies and to build capacity on the state level to manage nearshore and offshore sand resources.

Aron Stubbins’ paper journal cover story

Aron Stubbins’ recent work on deep-ocean hydrothermal vents  is the cover story for this month’s Nature Geoscience. Way to go, Aron! To read more about he story, click on the image.

Aron Cover

Survey season for Alexander lab

Surveying season is now officially here for the Clark Alexander lab.  After the successful completion of Wassaw Sound last year, Mike Robinson, Claudia Venherm and Lee Ann DeLeo will be surveying Ossabaw Sound for bathymetry and benthic habitat this summer.

During June, the lab team (Alexander, Jennifer Colley, Robinson, Venherm) were busy on Sapelo Island working within the context of the Georgia Coastal Ecosystems – Long Term Ecosystem Research (GCE-LTER) program.  They collected cores near sediment-elevation monitoring sites to compare seasonal/annual sediment accumulation rates to 100-y average rates.

“This comparison highlights the relative importance of daily and episodic sediment input to marsh accretion,” Alexander said. “In addition, we probed and augered transects from the upland out into the marsh to gather stratigraphic information for an upland runoff manipulation experiment.”

This experiment will modify the flow of groundwater from the upland to the marsh over a period of years to detect changes in salt marsh community structure, as a proxy for drought and development impacts to natural groundwater flows.

Skidaway seismograph detects Nepal earthquake

The seismograph planted in the meadow near Groves Creek detected the April 25th earthquake in Nepal.Earthquake Seismic Image

The seismograph was originally part of an NSF funded project of the Incorporated Research Institutions for Seismology. It was one of dozens of transportable arrays that were moved across the country and collecting seismic activity to image the deep earth several years ago. When the project was completed, the Skidaway station was transferred to another project to monitor earthquakes in the US.  The array is powered by the solar panel that many have seen on the northern end of the Groves Creek meadow.