Uranium-Thorium Age Model
of Yucatan Carbonate Sediments
Collaborator: Dr. Adi Torfstein
Impacts of Dry Atmospheric Deposition on trace metal and Pb isotopic composition in Seawater, Particulate Matter and Sediment in Gulf of Aqaba, Red Sea
Collaborator: Dr. Adi Torfstein
Collaborator: Dr. Adi Torfstein
Dry atmospheric deposition (DAD) is an important source of pollution to water bodies. The Gulf of Aqaba (GoA) lacks river input and precipitation during the summer period thus DAD may contribute major pollution to the ocean. While papers discussing how DAD influences seawater chemistry in the GoA are available only few include discussion of particulate matter in the water column. Specifically, we have a limited understanding of how DAD alters water and particulate matter chemistry on relatively short time scales. In this study I want to assess the relationships between DAD fluxes, DAD chemical characteristics, and its impact on water and particulate matter chemistry by collecting and analyzing chemical properties of aerosol, water, particulate matter and sediment in the GoA. We will collect total suspended particulate (TSP) samples by high volume TSP sampler daily. Profiles of seawater samples will be collected on research vessels, sinking particles (SP) will be obtained from sediment traps, suspended particulate matter with high volume pumps and surface sediments will also be obtained. Trace metal (Al, Mn, Fe, Co, Ni, Cu, Zn Cd and Pb) and Pb isotopic composition in DAD, seawater, SP sediments will be analyzed to determine impacts from DAD. An atmospheric deposition model base on meteorology and particle sizes will be applied to estimate flux of trace metals and particularly Pb input into the gulf, and a mass balance model used to obtain a mechanistic understanding of Pb cycling in the GoA. Obtaining these data can improve our understanding about atmospheric pollutants input and cycling in the Gulf of Aqaba.
Gene Expression
Changes of Red Sea Coral in a Combined High Temperature Low pH Laboratory
Experiment
Collaborator: Dr. Maoz Fine
During the IRES program, I am going to
research the combined effects of global warming and ocean acidification on Stylophora corals. The release of carbon
dioxide to the atmosphere through the burning of fossil fuels and deforestation
ultimately result in an increase in seawater temperature and ocean acidity.
These processes may result in coral bleaching and reduced calcification. During
two months, I am going to carry out a laboratory experiment with Stylophora coral nubbins which will be
grown in aquaria at different pH and temperatures to simulate future ocean conditions.
I am going to collect tissue samples to look for differences in gene expression
and symbiotic algae health during the experiment. Negative impacts on corals may have significant consequences
to the whole ecosystem: corals serve as food and shelter for other organisms and
they take part in the formation and preservation of coastal relief and sand
beaches. Therefore, a decline in the number, size or health of these calcifiers
may have cascade effects throughout the food web. Moreover the biodiversity in
reef systems is important since coral reef ecosystems provide many nature’s services
to coastal communities such as erosion protection from storms and economic activities
like fisheries and tourism. The results of this study will help to better
understand how corals may cope with climate change, and may provide useful information for the design of management
and conservation plans.
Quantifying Residence Times in the
Coastal Aquifer via Lab and Field Methods
Collaborators: Dr. Yishai Weinstein and Dr. Boaz Lazar
Concentrations
of nitrate, silica, carbon dioxide, all of which are important to ocean
chemistry, are subject to chemical transformations within the coastal
groundwater aquifer in addition to metals, and other solutes. The degree to which many chemical
transformations can occur within the coastal aquifer is limited by the
residence time of seawater within the coastal aquifer. Seawater enters the coastal aquifer through a
variety of mechanisms; the most common of which are wave and tidal action. Residence time (how long water remains in a
certain reservoir) of seawater in the coastal aquifer is a dominant factor controlling
the biogeochemistry of the coastal aquifer. Shorter residence times of seawater
in the coastal aquifer translates to less time for seawater to react and mix
with groundwater and aquifer substrate, while longer residence times translate
to more time for mixing and reactions to occur.
Yet, little is known about how short or long the residence times of
seawater in the coastal aquifer typically are.
I will use short-lived radium isotopes (Ra-224 and Ra-223) to quantify
residence times in a coastal aquifer in the Gulf of Eilat, using novel lab
experiments combined with field observations. Joseph Murray
Constraining
the Nitrogen Budget of the Gulf of Aqaba: A Nitrogen Isotope Approach
Collaborator:
Prof. Ilana Berman-Frank
The
Gulf of Aqaba is a long, semi-enclosed ocean basin located at the northeastern
end of the Red Sea. The local climate is extremely arid, with little to
no rainfall and no riverine input, with very high rates of surface water
evaporation. This situation causes the Gulf to exhibit a reverse estuarine
circulation pattern, where surface waters from the Red Sea pass through the
Straits of Tiran, bringing north large volumes of low nutrient surface seawater
into the Gulf. To balance this inflow, deep, relatively nutrient rich
waters flow south back through the Straits out into the Red Sea. By
simple mass balance, this circulation pattern results in a net loss of
important nutrients, including inorganic nitrogen, from the Gulf, and yet the
basin appears to be roughly in steady state with respect to its nitrogen
balance. Therefore there must be at least one, if not several,
significant external sources of new nitrogen to the Gulf in order to support
primary productivity in the Gulf. Recent work by a number of different
scientific research groups has attempted to quantify potential inputs of new
nitrogen to the Gulf of Aqaba. These sources include dry aerosol
deposition, biological nitrogen fixation, remineralization of deep sea
sediments, submarine groundwater discharge, and anthropogenic activity.
However, a full accounting of these estimates still shows an imbalance in the
overall nitrogen budget for the Gulf. Here, we propose to use a
combination of past approaches, along with several new nitrogen isotopic
methods, in order to attempt a full understanding of the sources, sinks and
processes important for the marine nitrogen cycle of the Gulf of Aqaba.
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