William Craig Burnett - US grants

Proposal Objectives and Relevance to Program Objectives: The U.S. investigators will work with William James McCabe from the Institute of Nuclear Sciences located at Lower Hutt, New Zealand, over a period of two years. The project is aimed at the development and application of a new method for the separation of isotopes. The radio chemistry group at New Zealand's Institute of Nuclear Sciences has developed a new process for the chemical separation of uranium, thorium, and protoactinium from geologic samples. The method, based on temperature-controlled ion exchange techniques and rotating disc electrodeposition, provides quantitative recoveries of these elements. This project seeks to improve the method by including simultaneous separation of polonium, radium, lead, and other elements. In addition to further enhancement of this new technique, several applications to on-going research projects at both institutions are planned. These projects include a study of radiochemical contamination of ground water in southwest Florida and dating of Pleistocene terraces in New Zealand. The combination of techniques and of expertise of the U.S. and New Zealand scientists helps fulfill the objective of the Program of promoting research of mutual benefit to both countries. Merit: The use of the technique pioneered in New Zealand with the further development by the U.S. investigators holds considerable potential for continued benefits. The introduction of this technology into the U.S. will provide an opportunity to expand the available dating techniques for small, low-yield samples common in ocean sciences. The project has been recommended by the Marine Geology and Geophysics Program for funding with high priority, and will take place with the concurrence of the New Zealand executive agent for the cooperative program. Relation to Other Projects and Funding: The research proposed here represents the addition of an international collaborative effort to research currently being supported domestically by the Marine Geology Program (OCE 85-20724) and by the Florida Department of Environmental Regulation. There is no duplication of funding, as this award provides only foreign travel, communication and support for the shipping of samples.

Three senior U.S. scientists, S. R. Riggs (East Carolina University), R. E. Garrison (U.C. Santa Cruz), and J. A. McKenzie (University of Florida), in addition to the principal investigator, will work with Dr. R. J. Cook, Chief of the Division of Continental Geology of the Bureau of Mineral Resources in Canberra, and colleagues in a project aimed at increasing our understanding of the nature and origin of sedimentary phosphate deposits in various on- and off-shore areas of Australia. This knowledge may shed light on the use of phosphorites to explain how major chemical and biological changes occur through geologic time. Phosphate deposits in Australia will be studied both in the field and in the laboratory through sedimentological and geochemical research methods jointly by the U.S. and Australian scientists. Such questions as: how phosphates are precipitated to form phosphorites; whether the biota of phosporites is unique; under what depositional conditions phosphorites are formed; what chemical/biochemical processes are involved in the weathering of phosphorites; and, whether the processes involved in the formation of phosphorite have varied over time, will be addressed. The Australian and U.S. groups have complementary expertise for this study, and both sides will benefit from a synergetic approach. The project fulfills the Program's objective of supporting research of scientific benefit both to Australia and the United States, and of providing access for U.S. scientists to the research environments and expertise of their Australian colleagues. The research propsed here extends studies being conducted by the investigators under other NSF grants (e.g., OCE 85-20724), to include _ _ data on Australian phosphates, and the use of various cross- disciplinary techniques available in Australia. This award provides travel and subsistence for one trip to Australia for each of the four senior researchers involved in the work. Results of the proposed research should lead to increased understanding of the processes involved in the evolution of the earth. In addition, both Australian and U.S. investigators will benefit from bringing the varied experimental techniques of sedimentology, paleobiology, oceanography, microbial ecology, and remote sensing to problems of this type. The project will take place under the aegis of the Agreement betweeen Australia and the United States for Scientific and Technical Cooperation.

Submarine springs and seeps discharge a substantial but not precisely defined quantity of water into the ocean. Recent estimates suggest that the magnitude of this discharge, driven by gravitational and convective forces, may be globally significant. Discharged fluids may consist of fresh water, connate waters, brines derived from evaporite deposits, or recirculated seawater. Because the composition of submarine hydrologic discharge may be markedly different than seawater, this process is capable of contributing significantly to the marine geochemical cycling of many elements. The proposed research will determine the potential of using water column standing crops of the tracers 222Rn, 226Ra and CH4, constituents greatly enriched in groundwater relative to seawater, for the purpose of locating and assessing submarine groundwater discharge to the ocean. A detailed geochemical mass balance will be constructed for the single best tracer, 222Rn, within a relatively small area on the continental shelf of northwest Florida, an area where we expect to find appreciable submarine discharge. Groundwater tracer concentrations and fluxes will be measured, both in the form of discrete springs and as disseminated seeps. Benthic fluxes and other processes, such as advection and air-sea exchange, which contribute to changes in the water column standing crop will be evaluated. These measurements will be modeled to evaluate the prospects of developing a simple tracer-based technique for determining the magnitude of groundwater discharge to the ocean applicable to other areas.

The controls on phosphorize formation and mineralization rates will be determined by analysis of the upper several meters of the shelf sediments from cores sampled during ODP leg 112 and several wide-diameter cores to be sampled during two future expeditions. Detailed chronostratigraphic analysis will be obtained by stable isotope analysis of benthonic foraminifera, bulk sediment dating and absolute dating interdispersed authigenic minerals and shell material. These data will allow the PIs to relate the formation and occurrence of phosphorize to environmental parameters over a time scale of hundreds to tens of thousands of years.

This award is under the International Postdoctoral Fellows Program, which enables U.S. scientists and engineers to conduct three to twelve months of research at foreign centers of proven excellence. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a four-month postdoctoral research visit by Dr. Carter D. Hull of Florida State University to work with Dr. Gudmundur Palmason at Orkustofnun (Icelandic National Energy Authority) in Iceland. This research project takes an integrated approach for producing detailed thermal and fluid histories of hydrothermal systems. Fluid, vein mineralization, and reservoir rock samples from geothermal systems will be collected, identified, and analyzed during the four month period. Chemical geothermometers will be applied and multicomponent chemical equilibrium models developed with the fluid analyses. Light-stable isotopic ratios and the activities of radionuclides in the 238U and 232Th decay series will be measured for selected fluids and minerals. Light-stable isotopic data can be used to characterize fluids and applied in studies of water-rock interaction. The ages of hydrothermal minerals, redistributions of radioisotopes, and residence times of fluids in the reservoir can be calculated from disequilibrium in the U-Th series. U-Th disequilibrium and the distribution of radionuclides in hydrothermal systems can be very useful as natural analogs for the transport and sorption of radionuclides in repositories. This award recommendation provides funds for a stipend of four months, international travel, an allowance for in-country travel, chemicals, and excess baggage and an administrative allowance for Florida State University.

This project focuses on the balance between riverine and submarine groundwater discharge in Southeast Asian coastal zone areas dominated by large rivers. Using geochemical tracers (radon and radium isotopes), the researchers will study both groundwater and river-derived fluxes in two river-dominated systems in which they have established strong international partnerships: (a) The Yellow River-Bohai Sea and (b) the Chao Phraya-Gulf of Thailand. Parallel biogeochemical studies to be performed by international collaborators will permit direct comparisons of the river- and groundwater-derived inputs of biologically relevant chemical species to the coastal zone. The project will contribute to human resource development in developing countries and the U.S. and will have important implications for coastal zone water resource management in highly populated areas.

EAR-00521201
Salters

This award, made through the Major Research Instrumentation (MRI) Program, provides partial support for the purchase of a Multicollector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS), and associated hardware. The instrument will be housed in a new Plasma Analytical Facility (PAF) at the National High Magnetic Field Laboratory (NHMFL).
We will use the instrument for:
- mantle geochemistry to constrain the processes that result in mantle heterogeneity as the instrument allows improved analyses of Hf and Pb isotopes as well as in-situ trace element analyses;
- cosmochemistry by measurement of heavy elemental abundances in extra terrestrial materials. returned from the GENESIS and STARDUST missions. For this project the MC-ICP-MS will be coupled with a single collector instrument for the determination of the major elements.
- low temperature geochemistry where the MC-ICP-MS allows metal stable isotope analysis. Foremost will be Fe-isotope analyses to investigate the cycling of Fe in the oceans. The MC-ICP-MS will be instrumental in our development of a Biogeochemical Dynamics Program, an interdisciplinary program that will focus on the interplay between chemistry and biology in aquatic ecosystems and which will make use of the unique instrumentation at the NHMFL. We will develop the protocols to measure the isotopic composition of environmentally significant metals like Cu, Zn, Mo and Hg.
At the NHMFL the instrument will also be of use to the material science and condensed matter physics faculty.

ABSTRACT

OCE-0451379

Over the past few years, some methods have been developed to assess submarine groundwater discharge (SGD) on a local scale. However, methodologies for regional scale evaluations (i.e., >100 km) have not occurred. For this reason, a scientist from the University of Hawaii, in collaboration with a scientist from Florida State University, plan to develop a three tiered approach to assess SGD into the sea at regional scales using the following methods: (1) high resolution, temperature calibrated (<0.1'C) geo-corrected aerial infrared surveys; (2) ground-truthing selected sites via natural geochemical tracers (223Ra, 224Ra, 227Th, 228Th); and (3) upscaling the results via typology. The PIs have selected the Kona coast for their study site because of its high apparent SGD, focused nature of the discharge, and lack of surface drainage. Once discharge is established, fluxes of nitrogen species, total phosphorus, inorganic phosphorus, silica, and total chlorophyll will be calculated for the Kona coast and placed within a regional and global context by comparison to stream fluxes.

As regards broader impacts, this study will provide scientists with a new method to assess submarine groundwater discharge on a regional scale, as well as yield new insights into the impact of submarine groundwater discharge on water budgets and biogeochemical cycles in the coastal ocean. The benefits of this study will extend from oceanographers to hydrologist to coastal and water resource managers. Students from both the University of Hawaii and Florida State University will participate in the research study.

ABSTRACT

OCE-0520723

Submarine groundwater discharge (SGD) represents an important, yet largely unquantified pathway for nutrients and other dissolved constituents from land to the coastal ocean. Coastal oceanographers and hydrologists have shown that slow yet persistent seepage of fresh groundwater through sediments occurs wherever an aquifer with a positive head is hydraulically connected to a surface water body. It is now recognized that a considerable amount of seawater is also recirculated through coastal aquifer systems and that both fresh and saline water inputs contribute nutrients and other dissolved solids to coastal waters. However, the relative importance of the driving processes and the extent to which saline water flow is coupled to fresh water discharges is still not well understood and the predictive capabilities are lacking.

For this reason, researchers at Florida State University will investigate the forces that drive both fresh and saline groundwater discharges. Since both terrestrial (hydraulic gradient, seasonal recharge cycle) and marine (wave setup, tidal pumping, water level differences) forces drive subsurface fluid flows through coastal aquifers and nearshore sediments, this team of scientists will examine these processes via a cross-disciplinary approach. It is critical to tackle the problem of SGD from both ends (terrestrial and marine), and from both disciplines (hydrology and oceanography) because driving forces overlap in time and space and the resultant fluid flow measured through coastal sediments is often a result of composite forcing. The project will separate and evaluate these forcing functions by a combination of long-term measurements (i.e., isotopic tracers, seepage meters), hydrological/geophysical investigations, and numerical modeling. The goal is to develop a long-term data set on all parameters that are relevant to SGD and its driving forces. Since many SGD drivers have known temporal variations, the frequency of the parameters and the ensuing SGD responses will be measured to deconvolute the influence of the forces.

In terms of broader impacts, this study will significantly advance our understanding of the mechanisms controlling SGD. Proposing to carry out the work prior to coastal development at the site will provide a baseline from which to assess the impact of commercial/residential development on coastal aquifers in the future. To disseminate information to coastal zone manager on SGD and its implications, a workshop will be held during the third year of the project. Graduate and undergraduate students will be involved in the field and laboratory studies of the project.

0809040
Burnett
This project supports collaborative research by Dr. William Burnett, Florida State University, Tallahassee and Dr. Ayman El-Gamal, Coastal Research Institute, Alexandria, Egypt. They plan a study on ?Study of Nutrient Fluxes Submarine Groundwater Discharge into the Coastal Zone Around Alexandria?

Technical Merit: Submarine groundwater discharge (SGD) represents an important, yet largely unquantified pathway for nutrients and other dissolved constituents from land to the coastal ocean. Coastal oceanographers and hydrologists have shown that slow yet persistent seepage of fresh groundwater through sediments occurs wherever an aquifer with a positive head is hydraulically connected to a surface water body. It is now recognized that a considerable amount of seawater is also recirculated through coastal aquifer systems. Both fresh and saline water inputs contribute nutrients and other dissolved solids to coastal waters. This project has three distinct objectives: (1) investigate the role of SGD in the delivery of nutrients to the coastal zone around Alexandria, Egypt; (2) estimate groundwater fluxes using natural radioisotopes; and (3) contribute to the dissemination of knowledge concerning SGD, measurement techniques, and its potential coastal management implications in Egypt. The selected site is located near Alexandria around the outlet of West El-Nobareya Drain (about 21 km west of the center of Alexandria). Groundwater is found at shallow depths in the vicinity of Alexandria. In addition, the groundwater quality is deteriorating as a consequence of the infiltration of contaminated surface water into the aquifers. The PIs will use automated radon monitors for continuous measurements of SGD flow over various time periods. They plan to construct a detailed nutrient budget for the site. Potential sources of nutrients to this area include surface water inflow, atmospheric deposition, diffusion across the sediment water interface, and SGD, that is currently unknown. This would likely be the first groundwater discharge study in North African coastal waters.

Broader impacts: Human resource development will be an important aspect of this project via capacity building in a developing country and meaningful graduate student participation in the field studies and other aspects of the research. A graduate student at Florida State University will have the opportunity to add to his Ph.D. research during this project. The project also involves important coastal zone management issues as the urban coastal system being studied has suffered from over consumption of groundwater, subsidence relating to this over pumping, and increased contamination from fertilizer, sewage, and other pollution sources. Nutrient inputs from contaminated groundwaters have been implicated in the eutrophication of near-shore waters and the increasing occurrence of harmful algal blooms offshore. This project is being supported under the US-Egypt Joint Fund Program.

Numerous studies over the past few decades have shown that submarine groundwater discharge (SGD) transports significant quantities of nutrients to estuaries and nearshore oceans worldwide. So far, none of the geochemical and hydrological studies of SGD have demonstrated a clear ecological role. At the same time, studies of microalgal community dynamics have suggested, but not verified, that SGD is an important determinant of community structure. We thus have neither thorough SGD investigations with inferences about ecological responses nor detailed observations of microalgae with only an inferred linkage to SGD. Attempting to assess the role of SGD on microalgal dynamics is complicated by two factors. First, discharge occurs through the benthos, which in near-shore waters is the niche inhabited by benthic microalgae. The microphytobenthos (MPB) can be present at densities orders of magnitude higher than the phytoplankton and have repeatedly been shown to alter nutrient efflux. The role of the MPB as a sink for nutrients will depend on their growth rates, which are in turn largely driven by temperature and light availability. The second complicating factor is that SGD can be highly episodic and its nutrient content very variable. The effect of SGD on the phytoplankton assemblage may be due to nutrient delivery and/or to dilution (reduction in competition and grazing pressure) and altered residence times. The time-scales of SGD and community response are difficult to assess by standard sampling methods.

This project will to investigate the link between SGD and microalgal dynamics in Little Lagoon, Alabama, a model system for such a study. In contrast to most near-shore environments, it is fully accessible; has no riverine inputs; and is large enough to display ecological diversity (c. 14x 0.75 km) yet small enough to be comprehensively sampled on appropriate temporal and spatial scales. The PIs have previously demonstrated that the lagoon is a hot-spot for toxic blooms of the diatom Pseudo-nitzchia spp that are correlated with discharge from the surficial aquifer. This project will use state-of-the-art techniques to assess variability in SGD, the dependence of benthic nutrient fluxes on MPB abundance and productivity, and the response of the phytoplankton to nutrient enrichment and dilution. The work will integrate multiple temporal and spatial scales and will demonstrate both the relative importance of SGD vs. benthic recycling as a source of nutrients, and the role of SGD in structuring the microalgal community.

Broader Impacts: Although this project is geographically restricted, its findings should be far reaching. Groundwater-born nutrient enrichment is now normal where agriculture occurs over porous soils, including in New England, Maryland/Delaware, Florida, Alabama, likely Texas, Yucatan (Mexico), California, Korea, Japan, and the Netherlands etc. The likely dependence of coupling between SGD and phytoplankton composition is likely to be driven by temperature and the frequency/intensity of precipitation, both of which will change in the Northern Hemisphere, according to the IPCC. The phenomenon therefore has wide application. This project will provide training opportunities for three Ph.D. students and the findings will be incorporated into several courses: Physiological Ecology of Microalgae (MacIntyre), Global Biogeochemical Cycles (Mortazavi) and Environmental Radiochemistry (Burnett). Last, this project will build on the PI's active partnership with local citizens, members of the Little Lagoon Preservation Society (LLPS), in bi-weekly monitoring of water quality and microalgal community composition. Members of the PI's lab have presented talks at each of LLPS' quarterly meetings for the past 2 years. These are attended by local stakeholders, local and state political representatives, and members of the press, and have proved to be an effective means for outreach and education on eutrophication, HABs and hypoxia. The relationship has been reported on extensively in the local press and praised as exemplary in an editorial in the region's largest newspaper.

The research team aims to study cave aerodynamics and dripwater chemistry to better understand how speleothems grow and how they incorporate paleoclimate signals into their calcite bands. This research complements an ongoing monitoring campaign established in Hollow Ridge Cave (HRC), Marianna, Florida.

As part of ongoing efforts, the researchers have been able to establish a simple model for cave air exchange with outside air and, thus, the rate of carbon dioxide ventilation in and out of this cave as it breathes. This has been achieved by continuously measuring 222Rn (radon), carbon dioxide, temperature, barometric pressure, relative humidity (in situ air density), rainfall (cave drip rates), wind speed and direction (cave air flow), and solar irradiance.

By expanding this array of in situ cave monitoring instruments to determine high resolution 3D and temporal air and water (drip) flow and chemistry through the cave (hydraulics), the researchers aim to provide a better understanding of the processes and environmental controls on using speleothems as paleoclimate proxies. In effect, the research team will calibrate the isotopic and chemical signals preserved in ?modern? calcite precipitated in a well-understood cave with the isotopic and chemical signatures in the cave air and drip.

The researchers plan several specific experiments that include: (1) deploying a dense array of micro-scale temperature and air flow sensors to map ventilation; (2) measuring existing active stalagmites for growth rates and isotopic and trace element compositions; (3) analyzing rainwater and drip water for chemistry and isotopic composition (time series); (4) running benthic flux experiments to establish rates of 222Rn emanation into the cave from limestone walls and drips; (5) establishing internal exchangeable cave air volume; (6) dye-chasers to estimate the epikarst volume and flow patterns; and (7) hydraulic groundwater gradients around the cave.

The primary broader impacts involve the potential for improved understanding of the limitations and utility of a widely used climate proxy and the support of undergraduate and graduate students.