Circulation and Mixing in Winyah Bay: An Observational Approach

Presenter: Diane Fribance (CCU)

Winyah Bay is a fairly large and complex local estuary, with diverse ecosystems and inputs from a variety of rivers. Prior studies have started to explore the circulation patterns and the driving forces behind tidal and residual circulation in this system. Using recent data acquired during May 2014, I will review what we know so far and what information is necessary to get a better grasp on the dynamics of this system. Two cross-sections in particular will be described, including what are likely the first energy dissipation estimates for this region. The high tidal velocities provided a challenging environment for vertical microstructure profiles, obtained over six days. The complex interactions of tides, winds, and changing river input make this region a good candidate for future observation and possible numerical modeling.

CCU's 2014 Hurricane Forecast on the Mark

As shown in the table below, the HUrricane Genesis & Outlook (HUGO) forecast was successful in range in every category with some exact hits. For example, the HUGO forecast value predicted the key accumulated cyclone energy (ACE) value to be 65 and the actual value was 64.7. Likewise the HUGO forecast range for the number of U.S. Atlantic Ocean Basin coastline land-falls was between 0 and 2 and the actual number of land-falls was 1. For the 2015 hurricane season, the HUGO team plans to further refine its Outlook and Land-Fall forecast capabilities.

Join us today for this week's seminar!

Join us this afternoon for 2 seminar presentations by graduate students Amanda Roach and Karsen Schottleutner.
When: Nov. 20 @ 3:00PM
Where: BCCMWS 100

Revisiting Submarine Mass Movements along the U.S Atlantic Continental Margin: Implications for Tsunami Hazards

Presenter: Karsen Schottleutner

A peaked interest in the generation of tsunamis by submarine mass movements has created the need for a better understanding of submarine landslides, specifically offshore of the eastern U.S. Through the acquisition and analysis of bathymetric data, GLORIA sidescan sonar data, seismic reflection profiles data, and core data Chaytor el al. was able to better define the extent and thickness of individual and composite submarine landslides along the continental slope and rise. They observed the morphology of deposits in order to identifying types of landslides in this region. Failures seem to originate on either the open-slope or in submarine canyons in the eastern U.S. region. Slope-sourced failures prove to be larger than canyon sourced failures, suggesting they have a larger potential to create tsunamis. This research discusses the material volume disturbance that occurs during individual failure events along with composite failure events. By understanding the underlying geology this research was able to better understand the potential of the submarine landslides to initiate tsunamis along the U.S. Atlantic margin.

Andrews B, Brink T, Buczkowski B, Claytor J, Twichell D (2007) Revisiting Submarine Mass Movements along the U.S Atlantic Continental Margin: Implications for Tsunami Hazards. Springer: 395-403.

The Effects of Mechanical Integrity of Hardbottom Habitat on Recruitment of Sessile Fauna

Presenter: Amanda Roach

Hardbottom habitat is characterized by exposed consolidated sediments which may or may not be colonized by sessile invertebrates such as corals and sponges. Recent efforts have been made to delineate hardbottom areas near the proposed Charleston Harbor expansion channel using a combination of geophysical methodologies. Bathymetric surveys were supplemented with video groundtruthing which revealed an interesting pattern of recruitment of sessile invertebrates to rocky outcrops. The varying recruitment of benthic fauna to natural hard bottom has been studied for variables such as reef morphology and hydrodynamics but the material of hard bottom itself has not been evaluated as a factor in this recruitment. Evaluation of the mechanical integrity of identified hardbottom areas may be accomplished through the employment of divers for visual and physical collection of rocky hardbottom samples. This study becomes important as the hardbottom material destroyed in the channel expansion project will be mitigated for through artificially created reef dump sites. Significant findings relating the mechanical strength of the hardbottom material and recruitment may be considered when creating these artificial reef sites around the channel. 

Join us today for this week's seminar!

Join us this afternoon for 2 seminar presentations by graduate students Matthew Kestner and 

Understanding the Distribution, Density and Demography of MacGillivray’s Seaside Sparrow in South Carolina

Presenter: John Laskaris

Understanding the dynamics between sea level rise and management strategies upon endemic tidal marsh birds will help increase effective conservation methods.  By using a population viability analysis (PVA) to evaluate the relative impacts of two sea level rise scenarios and two prescribed fire management scenarios on seaside sparrows, Kern et al. determined marsh loss via sea level rise to have the greater impact on sparrow population viability than management via prescribed burn.  These results have significant implications on the effectiveness of traditional marsh management strategies, which have positive effects on seaside sparrow persistence but do nothing to reduce rate of marsh loss. Marsh management strategies should therefore shift from traditional methods to proactive management strategies including assisted accretion and facilitated marsh transgression. 

This research has important implications for wetland conservation in the southeast, where marsh management strategies differ substantially and are more geared towards management of impoundments. Little is known about the demographics and behavior of MacGillivray’s seaside sparrow, whose range extends from North Carolina to northern Florida.  Marsh loss via sea level rise, pollution, and increasing coastal development present a threat to this subspecies, along with wintering seaside sparrow populations and several other marsh endemics, whose populations depend on high quality, unfragmented marsh for food, nesting habitat and migration. 

The status of MacGillivray’s Seaside Sparrow in South Carolina is poorly understood due to difficulty in accessing salt marsh habitats to perform breeding bird surveys, and sheer volume of salt marsh habitat within the state.  By performing a site-intensive demographic study and statewide breeding bird surveys using adapted SHARP survey protocols, we can better understand the distribution, density and demography of MacGillivray’s Seaside Sparrow in South Carolina. 

Kern RA, Shriver WG (2014) Sea Level Rise and Prescribed Fire Management: Implications for Seaside Sparrow Population Viability.  Biological Conservation 173: 24-31

Variation in groundwater salinity in a tidal salt marsh basin, North Inlet Estuary, South Carolina

Presenter: Matthew Kestner

Salt marshes are very important to coastal ecosystems. Not only are they very effective storm buffers and nursery grounds, they are also highly productive. This productivity is influenced heavily by groundwater providing a geochemical exchange of nutrients. Carter et al, 2008 look at the brackish/fresh groundwater interchange to see how this interface changes over the course of a year. They focus in on how precipitation and evapotranspiration (ET) affect Crabhaul Creek, a tidal salt marsh basin at the boundary of terrestrial and marine environments in North Inlet. The installment of Piezometers where installed  in transects to measure salinity while monthly Electrical Resistivity data was collected at spring tides to monitor the fresh/brackish groundwater interface. The study then constructed hydrogeologic models using SUTRA Suite from the USGS to determine whether variations in freshwater infiltration could cause movement in the fresh/brackish groundwater interface. The resistivity showed a zone of freshwater to the west every month and would periodically migrate into the eastern part of the survey.

Resistivity models suggest two hydrologic flow systems within the marsh basin: a shallow, upper flow system in the top 1 m of the marsh mud, and a deeper flow system controlling the position of the freshwater-brackish interface (Carter et al, 2008). This upper layer is found to be ubiquitous dominated by tidal inundation.  At lower depths however, it appears that tides are not the dominant driving force. The models suggest that the sand layer is a preferred conduit for freshwater from the uplands to flow into the marsh. Rainfall events and ET where explored as driving forces but no pattern was developed. Electrical Resistivity was effective in defining the freshwater-brackish interface, but additional studies will be required to fully understand how ET and freshwater movement affect the deeper flows.

Join us today for this week's seminar!

Join us this afternoon for 2 seminar presentations by graduate students Aundrea Dolan and Jonathan Petrigac.
When: Nov. 6 @ 3:00PM
Where: BCCMWS 100

Swallow-tailed Kites: An Endangered Species in South Carolina

Presenter: Jonathan Petrigac

There are many endangered species of birds across North America. Although not federally listed the Swallow-Tailed Kite Elanoides forficatus is considered by the South Carolina Department of Natural Resources an endangered species. Other states that inhabit Swallow-tailed Kites list them as species of concern. Swallow-tailed Kites were previously found to nest in 21 states before the 1900s. These birds migrate from South America to the Southeastern U.S. to breed in the summer months. However after populations underwent a dramatic decline between 1880 and 1910 the current distribution has been limited to just 7 states including Texas, Louisiana, Mississippi, Alabama, Florida, Georgia, and South Carolina. The decline in population is mainly contributed to habitat lost due to agriculture development and other land conversion. The Waccamaw Wildlife Refuge currently supports the highest density of nesting Swallow-tailed Kites in South Carolina. The refuge and the surrounding areas are considered the northern most documented nesting area.

These birds have highly social behavior especially when roosting and nesting. Kites tend to roost and nest in clusters which present challenges because they desire particular habitat. Most of the Swallow-tailed Kite breeding grounds in the U.S. are unprotected so habitat alteration will not only displace a pair but larger numbers. Recent conservation efforts in Florida, Georgia, and South Carolina have applied management practices by researching survivorship in adults by satellite tracking and tagging nestlings with VHF transmitters to track dispersal. These management practices are important for the health of future populations of Swallow-tailed Kites.

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