MEES Colloquium 2016
Every year the MEES Program holds an annual Colloquium. The colloquium is designed to promote interaction among the students and faculty of the program regardless of their site location. Third and fifth year students, both M.S. and Ph.D., are also given the opportunity to present their current research to their peers and faculty mentors.
This year the MEES Colloquium was held at the University of Maryland, College Park. Over 100 people attended the event, which spanned a weekend in October. Students were given the opportunity to share their research, hear from our invited guest, Mr. Jim Purdue of Purdue Farms, and experience College Park after dark.
We began the weekend with a warm welcome and certainly appreciated hearing more about the new curriculum from Dr. Tom Miller. This was followed by our Plenary Speaker Mr. Jim Purdue who explained more about chickens than anyone can imagine and even managed to tie it to MEES. It was a fascinating look into his world of providing chickens and pork to market and their work toward providing products the customer wants. There was so much more breadth to the Purdue business. Tom Miller stretched our thinking with asking us to apply what Jim Purdue presented with what MEES faculty and students see as interesting opportunities in possible research. Four teams presented their brainstorming on Saturday morning. The Colloquium concluded with Dr. Bill Dennison’s thoughts on successful interviewing.
Every year, MEES Faculty Members "judge" the student posters and presentations. This year, with 30 students presenting, faculty had a hard time selecting the "best". Therefore, we were able to award 5 very lucky winners each $250 for their academic achievements! This award winners and their abstracts this year are below:
MULTI-SCALE MODELING OF SARGASSUM GROWTH AND TRANSPORT
Maureen T. Brooks and Victoria J. Coles
Horn Point Laboratory, University of Maryland Center for Environmental Science
The pelagic macroalgae Sargassum fluitans and Sargassum natans are keystone species in the Atlantic Ocean and Gulf of Mexico, where they serve as habitat and forage for a diverse floating ecosystem. Recent Sargassum wash-ups along the coastline in the Caribbean highlight the need for improved understanding of this organism. The seasonal distribution of Sargassum throughout the tropics and subtropics established via satellite and ship-board observations is at odds with a basin-wide circulation that tends to aggregate buoyant material in the central North Atlantic Subtropical Gyre. Mesoscale features such as eddies can reconcile these differences by physically dispersing Sargassum and altering local growing conditions through nutrient upwelling. Using high performance computing, a series of four coupled models including ocean circulation, biogeochemistry, Lagrangian trajectories, and Sargassum physiology, were applied to examine the effects of eddies on Sargassum growth and dispersal.
SULFATE-REDUCING BACTERIA PRODUCE HIGH LEVELS OF CHROMOPHORIC DISSOLVED ORGANIC MATTER
Jenna Luek 2, Kaitlyn Thompson 1, Michael Gonsior 2, Randolph Larsen1
1. St. Mary's College of Maryland 2. University of Maryland Center for Environmental Science
Chromophoric dissolved organic matter (CDOM) is the optically active constituent of dissolved organic matter (DOM) and is found in all natural waters, including sediment pore waters. This CDOM is important to regulate light attenuation and to protect aquatic organisms from harmful UV radiation. It consists of a mixture of aromatic and conjugated π-electron systems and hence absorb ultraviolet (UV) and visible sunlight. A subset of these chromophores are fluorescent and are generally referred to as fluorescent DOM (FDOM). During early diagensis and under anaerobic conditions, sulfate reducing bacteria (SRB) reduce sulfate into inorganic sulfur species, such as hydrogen sulfide, polysulfides, sulfites and others. Surprisingly, we found FDOM being released during sulfate reduction. Detailed optical properties analysis during anaerobic incubation of lake sediments at different sulfate and acetate concentrations, revealed a very strong correlation (R2=0.98) between FDOM and sulfate reduction rates. The SRB fluorescent signal matched closely to that of humic-like material. We suggest that either the direct release of SRB metabolites or the hydrosulfurization of DOM caused the observed FDOM signals. This is the first evidence directly linking the production of FDOM with the process of sulfate reduction during early diagenesis of organic matter in anaerobic sediments.
THE BACTERIAL COMMUNITY STRUCTURE ASSOCIATED WITH BIOFUEL-PRODUCING MICROALGAE
1Samuel Major, 2Deanna Stephens, 3Ema Pagliaroli, 4Ryan Powell and 1Russell T. Hill
Environmental Molecular Biology/Biotechnology
1Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science
2University of Maryland, College Park
3Baltimore Polytechnic Institute
4Manta Biofuel LLC
Third generation biofuels made from microalgae are an attractive source of energy due to their rapid growth and ability to be grown in wastewater, salt water, or fresh water. Due to this production strategy, fuel consumption from algal biofuels are carbon-neutral. Bacterial communities associated with microalgae can provide fixed nitrogen and vitamins such as vitamin B12. Similarly, the bacterial communities use algal exudates for nutrition and consume O2 generated from microalgal photosynthesis. In collaboration with Manta Biofuel LLC, we set out to elucidate which bacterial communities are closely associated with the microalgae used to produce biofuels in large man-made outdoor ponds. Water samples were collected during algal blooms and serially filtered in order to capture the biologic fractions for 16S and 18S rRNA gene sequencing by Illumina Next Generation Sequencing. This approach provides insights into the microalgal and bacterial community structure, enabling us to relate community structure to the quality of oil produced from the biomass by hydrothermal liquefaction. Unfiltered water samples were cultured for bacterial and algal strain isolation. There were significant differences in the bacterial communities between fertilized and non-fertilized ponds, as well as a change in the communities over time. Culturing efforts have revealed several bacterial species that appear to enhance the growth of selected microalga strains suggesting the production of a compound by the bacteria that promotes microalgal growth. On-going analysis will link bacterial and algal community structure to the quality of oil produced. Microalgal and bacterial community analysis has applications in fresh-water and marine systems for enhancing microalgal biofuel production.
CONTINGENT STRUCTURE OF NORTHWEST ATLANTIC MACKEREL EVALUATED USING OTOLITH STABLE ISOTOPES
Gray Redding, Cooper, L., and Secor, D. H.
Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science
Atlantic mackerel (Scomber scombrus) support an important commercial fishery and are prey for many larger species. Stock assessments for Northwest Atlantic mackerel currently assume a single stock, comprised of northern and southern contingents, with natal regions centered off coastal Nova Scotia and southern New England. We hypothesized that otolith δ18O and δ13C values could discriminate fish from these regions on the basis of hydrographic differences and help to retrospectively understand migration and contingent structure of mackerel. Archived otoliths from extensive libraries in both the United States (source: NMFS Northeast Fisheries Center) and Canada (source: Fisheries and Oceans Canada), as well as otoliths from Iceland (source: Marine Research Institute) were carefully milled to extract material corresponding to the first year of life. Initial investigation comparing solely US sourced otoliths from two subregions of the southern New England natal region did not reveal significant geographical variation in isotopic content, but interannual differences were observed that corresponded to trends in regional ocean warming and a shift in the Gulf Stream position. We are now extending these studies of isotopic variation geographically by analyzing otoliths from the northern natal region in Canada and the Icelandic outgroup.
MARK-RECAPTURE ASSESSMENT OF RECREATIONAL BLUE CRAB (CALLINECTES SAPIDUS) HARVESTS
Robert Semmler, Matt Ogburn, Elizabeth North, Robert Aguilar, Anson Hines
Smithsonian Environmental Research Center (SERC)
In the Chesapeake Bay, commercial blue crab (Callinectes sapidus) harvests are monitored through mandatory, annual harvest reporting. However, no such monitoring system exists for the recreational sector, which exclusively targets male crabs. Recreational harvest has not been assessed in almost 15 years, and prior estimates, currently incorporated in the stock assessment model, may no longer be accurate. This study uses a large scale mark-recapture program to assess relative exploitation between the two fishing sectors in 15 harvest reporting areas of Maryland, then extrapolates outward to generate statewide estimates of the ratio of recreational to commercial harvest. It also incorporates a wealth of movement information, provided by marked-crab recovery locations, and uses this information to refine exploitation calculations in a novel manner. Results indicate broad spatial variation in recreational fishing, with a majority of recreational harvests coming from tributaries in upper sections of the Bay, such as the Miles, Patuxent, and Severn Rivers. Using two traditional methods to assess the ratio of recreational to commercial exploitation (uR / uC), values range from 0.112 to 0.142. Incorporating movement information into this calculation further refines this estimate, giving a ratio of 0.138. Considering that the ratio of recreational to commercial exploitation currently accounted for in the stock assessment model is 0.080, recreational harvests could be underestimated by approximately 73%. Incorporating these updated estimates into the stock assessment model would better account for the exploitation of male crabs in Maryland, and could result