Selected Current Projects

Submerged Aquatic Vegetation Gardening

Funding Agencies: Mobile Bay Estuary Program, Alabama Department of Coastal and Natural Resources

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With this project, we intend to restore around 10,000 square feet of submerged aquatic vegetation (SAV) beds.  To do that, we will locate denuded sites suitable for SAV growth (good sediment, clear waters and low hydrodynamics) and plant seedlings collected from donor meadows.  To avoid inflicting any significant damage on the donor meadows, we will only collect a number of limited seedlings from any donor meadow.  Furthermore, we will collect the seedlings from dense areas within the center of the meadow so that the small bare zones created with our collection will be re-colonized with new plants in little time.  We will use well-established planting techniques to anchor the seedlings in the receiving locations.  The choice of suitable sites for SAV growth and appropriate techniques for planting will assure the success of the newly established meadows.  We will also evaluate the performance of our SAV restoration activities.  To document the degree of restoration success, we will track changes over time in plant density, coverage and a number of structural descriptors, such as plant size, length and width over time in all restored locations.  We will also compare these measurements in newly established beds with measurements obtained in stable, undisturbed beds that have pervaded for a long time.  If the process of restoration is successful, the attributes measured in the newly established beds should evolve towards the characteristics of long-pervading beds.

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Evaluating the role of restored black needlerush marsh (Juncus roemerianus) as a buffer of anthropogenic eutrophication of coastal systems: an isotope enrichment approac

Funding Agencies:   Mississippi-Alabama Sea Grant Consortium

Nitrogen enrichment of coastal waters due to anthropogenic alterations in the watersheds has become a world-wide, pervasive environmental problem.  This is urging scientists and managers to devise solutions to reduce the magnitude of the problem.  Past work suggests that fringing marshes may be one of those solutions when nitrogen is delivered to receiving open coastal waters mainly through groundwater discharge; as the groundwater plume traverses the rhizosphere of the marsh, a significant fraction of the nitrogen carried by the groundwater can be taken up by plants and stored as plant biomass or denitrified and gassed out to the atmosphere, thereby reducing the quantity of nitrogen entering the receiving coastal waters.  

  

Experimental demonstration of this hypothesis, however, is missing, particularly for black needlerush (Juncus roemerianus) marshes.  These marshes, which are abundant in the Gulf of Mexico, have suffered and continue to suffer substantial losses due to human development and, as a result, numerous efforts to restore them are under way.  The need to restore black needlerush marshes, along with their potential role as effective filters of groundwater nutrient delivery and the importance to demonstrate such a role, provide an excellent opportunity well within the priorities of MASGC.  Namely, we present two new designs of black needlerush restoration and we intend to demonstrate that restored marshes following those designs are effective filters of nitrogen inputs into open coastal waters via groundwater.  We also intend to characterize the processes responsible for nutrient filtration in the marsh rhizosphere (i.e. plant uptake, denitrification, incorporation into bulk sediment organic matter, and ammonification) to improve our understanding of how that filtration occurs and implement potential applications to environmental management needs.  To do that, we propose a series of isotope (15NO3) enrichment experiments where the accumulation of the isotope into the different targeted pools will be assessed as groundwater travels through the rhizosphere of the restored marsh.


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Long-term ecosystem dynamics in coastal lagoons of Perdido Bay, Florida

Funding Agencies: NOAA National Coastal Data Development Center

   

Over the past eight years we have been surveying three coastal lagoons in the Perdido Bay area. This work has been funded by several agencies, including NSF, the Mississippi-Alabama Sea Grant Consortium and the Alabama Center for Estuarine Studies. Three students have graduated from that work (one MS and two Ph.D.'s) and a good number of papers are in press or submitted. The variables measured comprise physical and chemical variables (water-column salinity, temperature, oxygen, light penetration, water-column dissolved inorganic nitrogen, dissolved organic nitrogen, particulate organic nitrogen, phosphate, and sediment pore water inorganic nutrients) and biological variables

(microalgal chlorophyll concentrations in the water-column and sediment, seagrass structure, biomass and productivity, seagrass nutrient content, epiphyte biomass, diversity and abundance of invertebrate fauna in seagrass patches and bare sediment, and system metabolism-gross primary productivity, respiration, and net community productivity for water-column, seagrass patches and bare sediment). Furthermore, the three lagoons cover a wide gradient of human pressure, from a pristine lagoon to a lagoon with a moderately developed watershed to a lagoon with a highly developed watershed, thereby allowing us to make inferences as to how human utilization of watersheds affects the health of coastal lagoons and services offered to humankind and wildlife. Thus, this research is proving instrumental for the creation of policies of environmentally-sustainable development and use of coastal watersheds by humans. We are continuing our survey and carrying out manipulative experiments to improve our understanding of these systems and our ability to create effective environmental policies

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Metal accumulation in aquatic primary producers: ecological consequences and potential application to early detection of metal pollution

Funding Agencies: Alabama Center for Estuarine Studies (Environmental Protection Agency)

The aims of this study are two fold. First, we intend to evaluate the use of a suite of freshwater primary producers as bioindicators of Hg and Pb contamination. To do that, water column and sediment, microalgae, rooted submerged macrophytes and marsh plants will be collected in three locations of the Mobile Delta (Alabama) that represent different levels of human-induced Hg and Pb contamination, and the concentrations in the producers will be compared with those in water-column and sediment in the three locations. Second, we will examine the effects of Hg and Pb contamination on several important physiological and ecological properties of the producers. Specifically, we will measure photosynthesis, growth, consumption by herbivores and decomposition of the producers in each of the field locations and, in the laboratory, we will expose the producers to higher metal concentrations than those found at the specific locations and measure the same processes as in the field.  The results will improve our understanding of the impacts of Hg and Pb pollution on freshwater ecosystems, namely (1) whether Hg and Pb concentrate in primary producers as metal loading rates into the ecosystem increase and, if so, (2) how higher concentrations in the producers affect total primary production and the trophic support of first-level consumers (herbivores and detritivores) in the ecosystem.

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Selected Past Projects

“Interactions between anthropogenic eutrophication and the black needlerush (Juncus roemerianus) marsh in the Gulf of Mexico: how is eutrophication affecting the marsh ecological role and to what extent can the marsh palliate the impact of eutrophication on coastal waters." ACES (Alabama Center for Estuarine Studies)/EPA (Environmental Protection Agency)/MASGC (Mississippi-Alabama Sea Grant Consortium).

Effects of anthropogenic eutrophication on the ecosystems services provided by shoalgrass (Halodule wrightii) meadows:  research and education. MASGC (Mississippi-Alabama Sea Grant Consortium).

"Ecosystem Services Provided by Oyster Reefs: An Experimental Assessment." NMFS – Habitat Conservation (National Marine Fisheries Service).  Principal Investigator with Ken Heck and Sean Powers.

"Examining the effects of Hurricane Ivan in Coastal Alabama and Northwestern Florida: A positive impact on shallow coastal lagoons?" NSF (National Science Foundation)/ACES (Alabama Center for Estuarine Studies)/MASGC (Mississippi-Alabama Sea Grant Consortium).

"Preliminary Evaluation of the Ecological Role of the Seagrass Halodule wrightii in Coastal Ecosystems: Towards an Assessment of the Impact of Anthropogenic Eutrophication on That Role."  MASGC (Mississippi-Alabama Sea Grant Consortium).

“Evaluating trophic processes as indicators of anthropogenic eutrophication in coastal ecosystems: an exploratory analyses.”  ACES (Alabama Center for Estuarine Studies).

“Effects of anthropogenic eutrophication on the magnitude and trophic fate of microphytobenthic production in estuaries.”  ACES (Alabama Center for Estuarine Studies), Principal Investigator with Jonathan Pennock (UNH).


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Last Date Updated: 03/03/08