Seminar Title: Coastal ocean response to near-resonant sea breeze/land breeze wind forcing near the critical latitude in the Georgia Bight
Presented by: Catherine Edwards , Ph. D. student, University of North Carolina at Chapel Hill
Date: Monday, October 27, 2008
Time: 2:00 p.m.
Where: SkIO Library Auditorium
Summary: Near the critical latitude of 30 deg N or S, the local inertial frequency coincides with the diurnal, and an increased response to diurnal forcing can be observed in both the atmosphere and in the ocean. On the mid- to outer shelf of the Georgia Bight, between 29-32 deg N, non-tidal diurnal currents can exceed 25 cm/s more than 120 km offshore, and are surface-intensified, with currents in the lower layer 180 degrees out of phase with those in the upper layer. Persistent from April through October, these diurnal motions appear to be inertial oscillations (IOs) and near-inertial internal waves (NIIW), forced by sea breeze/land breeze (SBLB), which is itself near-resonance.

Observational wind and current data from 1999-2007 are analyzed from a moored array in the Georgia Bight, where linear theory predicts a maximum of SBLB magnitude and offshore extent. The structure of diurnal variability in observed and modeled wind fields compares well with the predictions of linear SBLB theory, with the greatest SBLB winds near 30 deg N. SBLB is a source of shelf-wide wind forcing near the resonant frequency; SBLB winds are found to exceed 1-2 m/s at least 250 km offshore, a distance almost an order of magnitude greater than that found at other latitudes.

Though the SBLB winds decrease with distance offshore, the coastal ocean response increases as the presence of stratification increases the efficiency of the wind forcing -- preliminary analysis of surface currents from HF radar suggests continued increase past the shelf break into the Gulf Stream. A month-long glider deployment in August 2006 allows for a closer examination of the role of stratification in determining the magnitude and vertical structure of the SBLB-forced currents, and reveals that the pycnocline contains the return flow, rotating 180 deg out of phase with surface currents. This unusual vertical structure has significant implications for mixing, as the shelf of the Georgia Bight appears to trap near-inertial energy input from the wind, enhanced near the critical latitude for diurnal/inertial resonance.

Seminar Title: Assessing Biodiversity/genetic Diversity in the Marine Phytoplankton
Presented by: Linda K. Medlin, Observatoire Océanologique de Banyuls-sur-mer, Laboratoire Arago, 66651 Banyuls-sur-mer, France
Date: Tuesday, October 28
Time: 3:00 p.m.
Where: SkIO Library Auditorium
Summary: Marine phytoplankton are highly dispersed with large population sizes and are often considered to be homogenous over their entire range. Thus using this definition, one would predict that everything is everywhere for these microbes. However, recent molecular analyses have shown both spatial and temporal compartmentalization in phytoplankton communities, thus calling into question the idea that everything is everywhere. Molecular techniques can now address many important questions concerning taxonomic affinity, genetic diversity, gene flow and dispersal, and physiological states, of which all have an impact on the assessment of biodiversity and production in all aquatic systems. When comparing genetic diversity with physiological adaptation we see how the phytoplankton has maintained ecosystem resilience. Examples are presented to document the range of genetic diversity and population fragmentation that has been reported in the phytoplankton and a hypothesis as to how this relates to species evolution on a geological time scale is provided.

Sushi is a growing industry in the United States that can be economically stimulating if done on a commercial scale. Our research focuses on the parameters to successfully culture Gracilaria. Gracilaria is an edible seaweed with a profitable market so we are testing its viability as a biofilter in fish tanks. Our experiments include three different approaches at culturing Gracilaria. These include using black sea bass waste water in a recirculating system, a flow through seawater tank, and aquariums with varying nutrients and light. We believed that Gracilaria grown in sea bass water or in aquariums with no light would grow best. Our data has shown that Gracilaria can be cultured successfully by maintaining a temperature around 25° C, plenty of shade, continuous aeration, a pH of 8.5, and salinity of 34 parts per million.

The objective of the experiment is to observe the growth rates of Graciliaria cultured in variable environments. Optimum growth of Graciliaria can make a beneficial profit for commercial sales of seaweed. Graciliaria was observed in aquariums, flow through tanks, and a sea bass filter system. Twelve aquariums were observed with varying light and nutrient parameters. The flow through tanks circulate seawater from the river and the seaweed was suspended in crates.

The Graciliaria is stimulated by the absorption of nutrients from the sea bass waste, which in turn reduces the water toxicity for the sea bass. Amongst the several parameters tested, the Graciliaria showed best growth in the shaded aquarium medium.

The demand for seafood, including sushi, is increasing nationwide. Acknowledging this fact, Skidaway Institute of Oceanography has adapted a system of raising Black Sea Bass from fry to adult size using a diet of tilapia. I will discuss how raising fish from fry to market size will be a profitable business venture as well as the organic vegetables that can be aquaponically grown in conjunction. Using the information collected on both markets, I will develop a business plan which to include marketing, operations and financial information. Details needed to operate efficiently in this market will also be provided in the business plan. Not only will I provide information on the fish market but I will also answer the question, why we believe our fish should be considered organic.

The price of gas and biodiesel are quickly increasing day by day, and alternatives are being researched to find new sources of fuel. It has been discovered that through an extensive process, corn can be converted into biodiesel as well as ethanol. Using this principal, we designed an experiment to create biodiesel and ethanol using algae as our medium. We extracted carbohydrates and lipids, through filtration, from the single-cell algae, which could then be converted to biodiesel as well as fermented the filamentous algae to see if it would yield a high percentage of ethanol. Our results showed a 75% yield of carbohydrates from the filamentous algae and a 50% yield of carbohydrates from the single-cell algae. Also, we discovered that there was only a 3% yield of lipids for the filamentous algae, and a 6% yield of lipids from the single-cell algae. From these test results, we hypothesize that it will be possible to convert algae into biodiesel and ethanol.

Algae, a potential Bio-Fuel and Lucrative Business
Ashley Shannon - Clark Atlanta University

In response to the rising prospective profit and interest for bio-fuel, we designed a research project to look at the probability of profit that could be made from algae produced in Skidaway Institute of Oceanography’s tilapia raceways. My preliminary hypothesis includes a profit plan for use of the algal water produced in the tilapia aquaculture. Since the algae is a byproduct of the fish production, costs should remain fairly low. Through-out the past couple weeks, I have researched variable and fixed costs for this bio-fuel project as well as assisted in the research, finding the amount of carbohydrates and lipids available. Consequently we found that the concentration of lipids were low; however, there is a high percentage of carbohydrates, giving the option for fermentation to produce ethanol.