Craig Smith, Ph.D. - US grants

This is an application to become one of the cooperating clinics in the Optic Neuritis Treatment Trial (ONTT). The ONTT consists of essentially two research components: (1) a clinical trial of the efficacy of oral prednisone and intravenous methlprednisolone in reducing residual optic nerve damage in patients with optic neuritis; and (2) a study of the natural history of optic neuritis. In this proposal we document our patient recruitment potential and ability to perform this study according to protocol. Within a recent consecutive 12 month period our neuro-ophthalmology group of ophthalmologists and neurologists saw 24 patients with optic neuritis that met eligibility criteria for entry into the ONTT.

Three data acquisition and signal processing systems will be provided to implement a novel improvement in undergraduate instrumentation laboratories. The new idea addresses the need to teach digital data acquisition and signal processing techniques such as: concepts of dynamic system response, data sampling, leakage, aliasing, transformation, and others to mechanical-engineering undergraduate students. In the newly designed instrumentation curricula, spectrum analyzers are being used much like oscilloscopes were used previously. This new approach to undergraduate instrumentation permits students to learn techniques currently used in industry. These principles will be taught not only in the class room environment but also through newly designed laboratory experiments in two undergraduate instrumentation courses. The equipment will provide the laboratories with three work stations consisting of personal computer controllers, data acquisition and signal processing peripherals, and appropriate signal conditioning and excitation hardware.

This project involves the acquisition of three data acquisition and signal processing systems to assist in implementing an innovative approach in teaching instrumentation to undergraduate students. The new approach addresses the need to teach digital data acquisition and signal processing techniques such as: concepts of dynamic system response, data sampling, leakage, aliasing, transformation, and others to mechanical-engineering undergraduate students. In the newly designed instrumentation curricula, spectrum analyzers are being used much like oscilloscopes were used previously. The significance of this new approach to undergraduate instrumentation is due to the fact that industry heavily uses these techniques while they are not taught in the schools (at least in mechanical-engineering curricula). These principles will be taught not only in the class room environment but also through newly designed laboratory experiments in two undergraduate instrumentation courses. The equipment will provide the laboratories with three work stations consisting of personal computer controllers, data acquisition and signal processing peripherals, and appropriate signal condition and excitation hardware.

Rich animal communities fueled by carbon producing microorganisms are known from a variety of reducing habitats at the deep-sea floor including vents, seeps, and organic-rich sediments; these habitats generally are linked to the boundaries between plates and/or areas of high coastal productivity. During a recent dive with the submersible, ALVIN, in the Catalina Basin, scientists discovered a community fueled by a novel source of reduced carbon compounds --- the skeleton of a 20-m long whale. Preliminary evidence suggests that whale remains may provide persistent and abundant reducing habitats with faunal communities similar to those of seeps, vents and organic-rich muds. However, the significance of whale-skeleton reducing habitats cannot be rigorously evaluated without much better knowledge of at least: (1) the source and flux rates of reducing compounds, (2) community composition (including vent-seep affinities), and (3) community dynamics (e.g., persistence times) associated with these carbon rich microbial systems. This research will provide a descriptive and experimental program, using the Catalina Basin whale-fall as a case study, to address these three topics.

In 1991-1992, the US JGOFS Equatorial Pacific program will study the production, flux and fate of organic carbon along a cross-equatorial transect at 140oW. From the equator northward, this transect traverses a steep gradient in particulate organic-carbon flux and burial at the abyssal seafloor. In order to elucidate the fate of organic carbon in these sediments, an understanding of bioturbation and seabed particle dynamics (as traced by naturally occurring radionuclides) is essential. The P.I.'s propose to test, along this carbon-flux gradient, four hypotheses of biogoechemical significance: (1) bioturbation rates and depths vary with annual particulate organic-carbon (POC) flux to the seafloor, (2) these variations have a significant impact on the mineralization and burial of organic carbon in the seabed, (3) macrobenthic standing crop and mean body size are correlated with annual POC flux, and (4) seabed inventories of excess 234Th, 228Th and 210Pb are correlated with POC flux on 100-d, 10-yr and 100-yr time scales, respectively.

9521116 Smith The mechanisms and rates of sediment mixing by the feeding and movements of animals, termed bioturbation, may profoundly influence chemical recycling, microstratigraphy, and faunalcommunity structure at the deep-sea floor. Recent studies of ingestion by bottom-dwelling fauna suggest they consume newly sedimented, highly organic particles. If such selective feeding is widespread, biogeochemical models, based on single bioturbation tracers, would provide unreliable predictions about bioturbation, microbial metabolism, sediment diagenesis, and strata formation. This study will test three alternative, mechanistic hypotheses by: assaying ratiotracer activities in deposit-feeder guts and on sediment particles of various sizes. Specifically, tracer-dependent mixing may result from (1) sizedependent ingestion of Th- 234-rich particles by deposit feeders, (2) selective ingestion of young, food-rich particles by deposit feeders, independent of size, or (3) passive cascade and/or active sequestering of newly deposited particles in animal burrows. ***

The approach of this NCDDG is to continue to develop biodegradable polymers that can be implanted at the site of the tumor and release effective drugs in a controlled manner as the polymer is degraded. Other programs are concerned with research related to providing new polymers and delivery systems for anti cancer drugs. Our program is aimed at development and is designed to provide polymer-drug combinations in optimal, reproducible formulations so that they can be tested in animals (preclinical); the effective formulations will be then scaled-up and extensively studied to be appropriate for human clinical trials (beyond the scope of this proposal). Through the previous NCDDG we have established the requirements for a suitable degradable implant to the brain by using the BCNU-polymer combination as representative. During the course of bringing this device through clinical trials many chemical, pharmaceutical, and pharmacological issues were investigated and the appropriate procedures have been established. These include: scale-up and quality control procedures for polymer manufacturing and drug incorporation; toxicology of the placebo and BCNU-loaded polymer under various conditions; and new polymers and various drugs were introduced to the program. The specific aims of the current proposals are to 1) develop procedures for large scale production of clinical grade drug-polymer implants, focusing on the use of automated compression and injection molding processes, 2) develop methods to produce sufficient quantities of the new polymers and delivery systems developed,in other programs and supply of quality polymers and drug incorporated devices to the other programs, 3) Develop validated methods for the evaluation of the shelf life stability of anticancer polyanhydride delivery systems, 4) develop methods for studying Polymer-Drug interaction and protein stability in polymers, and 5) Determine the optimal gamma- irradiation sterilization dose for polyanhydride based delivery systems.

T lymphocyte

OPP98-15823 P.I. Craig Smith
OPP98-16049 P.I. David DeMaster

Primary production in Antarctic coastal waters is highly seasonal, yielding an intense pulse of biogenic particles to the continental shelf floor. This seasonal pulse may have major ramifications for carbon cycling, benthic ecology and material burial on the west Antarctic Peninsula (WAP) shelf. Thus, we propose a multii-disciplinary program to evaluate the seafloor accumulation, fate and benthic community impacts of bloom material along a transect of three stations crossing the Antarctic shelf in the Palmer LTER study area. Using a seasonal series of five cruises to our transect, we will test the following hypostheses: (1) A substantial proportion of spring/summer export production is deposited ont eh WAP shelf as phytodetritus or fecal pellets. (2) The deposited bloom production is a source of labile particulate organic carbon for benthos for an extended period of time (months). (3) Large amounts of labile bloom POC are rapidly subducted into the sediment column by the deposit-feeding and caching activities of benthos. (4) Macrobenthic detritivores sustain a rapid increase in biomass and abundance following the spring/summer particulate organic carbon pulse. To test these hypotheses, we will evaluate seabed deposition and lability of particulate organic carbon, patterns of particulate organic carbon mixing into sediments, seasonal variations in macrofaunal and megafaunal abundance, biomass and reproductive condition, and rates of particulate organic carbon and silica mineralization and accumulation in the seabed. Fluxes of biogenic materials and radionuclides into midwater particle traps will be contrasted with seabed deposition and burial rates to establish water-column and seabed preservation efficiencies for these materials. The project will substantially improve our understanding of the spring/summer production pulse on the WAP shelf and its impacts on seafloor communities and carbon cycling in Antarctic coastal systems.

Adult human islets proliferate when cultured using purified laminin-5 extracellular matrix. This ability to proliferate adult human islets ex-vivo has direct potential application to the treatment of diabetes through transplantation, but more importantly, readily allows the mechanisms of adult human islet proliferation to be studied. Understanding the processes occurring when islets expand in culture may lead to novel treatments to restore an adequate beta cell mass in diabetic patients. The overall objective of this research proposal is to understand the mechanisms leading to the ex vivo proliferation of adult human islets. The specific aims are as follows: 1) Determine fully the sequence of morphological and functional phenotype changes that occur when adult human islets proliferate in culture. 2) Determine the factors controlling the phenotype changes and regulating ex vivo adult human islet proliferation. Recently several gene transcription factors that control islet hormone production have in addition been found to play critical roles in the development of the pancreas. The proposed experiments are particularly focused on these transcription factors because they are very likely to be regulated during adult human islet proliferation in culture. To accomplish these objectives adult human islets will be proliferated ex vivo, and examined using cellular and molecular methods.

DESCRIPTION (Adapted from the Applicant's Abstract): The overall objective of this research application is to establish clinical protocols for simultaneous islet-kidney (SIK) transplantation in type 1 diabetic recipients that will provide long-term euglycemia and insulin-independence. Based on prior human islet transplants and experimental evidence, this clinical trial of SIK transplantation will apply proven and recently emerging methods and medications to achieve this goal. Overall, 10% or less of islet transplant recipients have achieved insulin-independence for any sustained period. The best reported results from a single center are four of 12 patients (25%) achieving insulin-independence following islet-kidney transplants. The specific aims are to overcome three obstacles that prevent better results in islet transplants: 1) low engrafted islet mass; 2) high metabolic demand and 3) immunologic graft loss. Preliminary data suggest that an improved two-step method for islet isolation, using a better preservation solution, is a means to increase the engrafted islet mass. Treatment of recipients with pravastatin may also increase the islet mass through its ability to prevent non-specific inflammatory damage to islets, as demonstrated in animal models. State of the art glycemic control with insulin pump therapy and subcutaneously implanted glucose sensors will help to prevent glucotoxicity. The investigators will use recipient treatment with thiazolidinedione class medications to lower the metabolic demand by increasing peripheral sensitivity to insulin. Anti-IL2 receptor monoclonal antibodies effectively prevent immunologic graft loss in animal models for diabetes. This trail will employ basiliximab, a chimeric anti-IL2 receptor antibody. Transplantation of peripancreatic lymphoid cells will also be used to prevent autoimmune destruction of the grafts. Outcome measures that will test the effectiveness of this protocol are arginine induced insulin release, euglycemic clamp insulin sensitivity indices and islet graft survival. Improvements in the success of SIK transplantation may eventually lead to more wide spread application of islet transplantation to the cure of type 1 diabetes.

Abstract
OPP-0096422 & OPP-0095904
P.I.s David Kadko & Craig Smith

The first discovery of chemoautotrophic community living on a seafloor whale-fall carcass was made in the Santa Catalina Basin in 1987. Subsequent discoveries in the Pacific and the fossil record confirm that such communities are widespread in the modern ocean and have occurred over evolutionary timespans. The communities supported by the whale-fall environment bear taxonomic similarities to other deep-sea reducing environments, such as hydrothermal vents, and may occur with an average spacing of an order of magnitude smaller than that for vent fields. Whale-falls are of biogeographical significance for the following reasons: 1) they enhance the biodiversity of the deep-sea; 2) they can provide insights into the effect of anthropogenic influences, such as sewage sludge emplacement and persistent organic pollutants (POPs) on the marine environment; and 3) their potential roles as stepping stones for sulfophilic species in the deep-sea. The proposed work will continue to develop radiochemical methods (using thorium, radon and lead isotopes) for estimating the ages of seafloor whalebone communities. Preliminary measurements, using radiochemical methods, performed on known age bone samples yield isotopic ages that are in good agreement with known ages. The proposed work will undertake the following: 1) establishment of a final protocol for the dating techniques previously developed and make this product available to the scientific community; 2) initiate the study of lipid content and lipid characterization on dated bone material to assess the residence time of lipids within fallen whale skeletons; 3) attempt to assess a record of pollution, particularly persistent organic pollutants (PCB, DDT) within well-dated skeletal remains of whales; and 4) determine rates of development, patterns of succession, and persistence times of whale-fall chemoautotrophic communities.

This project examines the seasonal variation in the nature of the organic carbon deposited on continental margins. The flux of organic carbon reaching the seabed can be quantified by using particle traps or by modeling seabed burial and regeneration rates, but the quality (i.e., its lability) has been difficult to assess on continental margins because of co-deposition with old refractory carbon from marine and terrestrial systems. Bomb Carbon-14 (C14) is a useful tracer of recently produced marine organic matter, but this signal is masked in continental margin particle?trap samples and surface sediments by the older and refractory carbon that is re-suspended and reworked from shallower marine deposits. Surface deposit feeders in continental margin systems have been shown to sequester the labile fraction of the total organic flux reaching the seabed as a result of their selective ingestive and digestive processes. Therefore, the body tissues and the gut sediments of these benthic fauna can provide a record of the labile material reaching the continental margin seafloor.

Initial C14 data indicate that the body tissues of surface depositing feeders are enriched in this radioisotope by 100 to 300 per mil relative to the surface sediments in which they live and feed. Based on mass?balance C14 calculations, the labile component may comprise only a few tenths of a percent of the total organic matter in the surface seabed, yet the surface deposit feeders exhibit C14 signatures in their body tissues (+20 to +80 per mil) dominated by the local bomb?produced signal . Thorium (Th) data from continental margins suggest that as much as 50% of the recently deposited organic matter on the continental margin sea floor may pass through the guts of deposit feeders prior to microbial degradation or burial. Therefore, C14 measurements on benthic fauna can provide a unique tool for assessing the lability of organic matter reaching the seafloor and for tracking the fate of this material in the benthic food web. Many existing diagenetic models treat organic matter regeneration by microbes and deposit feeders as a batch process with a single carbon degradation constant for the bulk organic matter. The C14 data clearly show that ingestion of organic matter and digestion of this material are very selective processes. The C14 analyses from the California Borderland and the Antarctic continental margin have shown the utility of this approach for documenting variations in the organic carbon lability of surface sediments.

Drs. DeMaster and Smith will expand the initial studies to enable assessment of seasonal variations in the quality of organic carbon deposited on the seabed. Particle?trap samples, benthic?faunal tissues, gut samples and surface sediments have been collected during 6 cruises to the California Borderland and 5 cruises to the Antarctic continental margin covering the major seasonal variations in organic carbon supply. Funds are requested for making 150 C14 analyses (and complementary C13, N15, and C/N measurements) on these samples so that a time series quantifying the nature and flux of organic matter reaching the seabed can be determined. They will assess not only seasonal variations in the nature of particle selection and digestive selection processes for organic matter, but also the changes in these processes as a result of feeding strategy (epibenthic surface deposit feeders, vs. subsurface deposit feeders vs. head?down subsurface deposit feeders) on the seafloor.

Abstract

The Antarctic Peninsula region exhibits one of the largest warming trends in the world. Climate change in this region will reduce the duration of winter sea-ice cover, altering both the pelagic ecosystem and bentho-pelagic coupling. We postulate that shelf benthic ecosystems are highly suitable for tracking climate change because they act as "low-pass" filters, removing high-frequency seasonal noise and responding to longer-term trends in pelagic ecosystem structure and export production. We propose to conduct a 3-year study of bentho-pelagic coupling along a latitudinal climate gradient on the Antarctic Peninsula to explore the potential impacts of climate change (e.g., reduction in sea-ice duration) on Antarctic shelf ecosystems. We will conduct three cruises during summer and winter regimes along a 5- station transect from Smith Island to Marguerite Bay, evaluating a broad range of benthic ecological and biogeochemical processes. Specifically, we will examine the feeding strategies of benthic deposit feeders along this climatic gradient to elucidate the potential response of this major trophic group to climatic warming. In addition, we will (1) quantify carbon and nitrogen cycling and burial at the seafloor and (2) document changes in megafaunal, macrofaunal, and microbial community structure along this latitudinal gradient. We expect to develop predictive insights into the response of Antarctic shelf ecosystems to some of the effects of climate warming (e.g., a reduction in winter sea-ice duration). The proposed research will considerably broaden the ecological and carbon-flux measurements made as parts of the Palmer Station LTER and GLOBEC programs by providing a complementary benthic component. This project also will promote science education from the 9th grade to graduate-student levels. We will partner with the NSF-sponsored Southeastern Center for Ocean Science Education Excellence to reach students of all races in all areas of NC, SC and GA. The project will also benefit students at the post secondary level by supporting three graduate and two undergraduate students. During each of the three field excursions, NCSU and UH students will travel to Chile and Antarctica to participate in scientific research. Lastly, all three PIs will incorporate material from this project into their undergraduate and graduate courses.

In the scholarly literature, human emotions are increasingly appreciated as representing highly context-specific responses that serve important adaptational functions at both intrapersonal and interpersonal levels. Intrapersonally, emotions are posited to serve important attention-regulatory functions, alerting the individual to adaptationally relevant events and preparing and motivating the individual to respond to those events. Interpersonally, through their physical expression, emotions are posited to communicate important information regarding the person's reactions and likely behaviors to others in the social environment. Given the importance of emotion in human functioning, it is vital to understand how emotions can be elicited in a highly context-specific manner. The ultimate goal of this line of research is to test for a causal role of appraisal, or internal evaluations, in eliciting emotional experience, and to test a key premise of a process model by examining the effects of incidentally primed appraisals on emotion and emotion-related behaviors. However, an important first step in this research is to demonstrate that appraisals can be primed effectively. Although strong effects of social priming have been found in other domains, priming of appraisals is a new research direction. Preliminary evidence suggests the feasibility of emotional priming, but this small grant will explicitly test a variety of priming manipulations, such as cognitive tasks and incidental exposure, to make sure they can effectively and uniquely prime specific appraisals. Several distinct appraisals, having specific hypothesized roles in differentiating emotional experience, will be targeted. These include appraisals of motivational relevance (an evaluation of subjective importance which determines the intensity of the emotional response), coping potential (the extent to which a person feels able to change or maintain circumstances in order to further her/his goals), and accountability (which tells the individual toward whom/what to direct coping efforts). Each targeted appraisal will be primed in two different ways, and the strength and specificity of the priming will be evaluated. The results of these studies will lay the groundwork for subsequent research that will directly test the effects of primed appraisals on emotional response. This research line will greatly strengthen the existing empirical evidence regarding the causal role of appraisal in the elicitation and differentiation of emotional experience, and further, will help provide a theoretical account of the cognitive processes underlying emotion elicitation. The development of this theoretical account in turn will have great utility for understanding the functioning of emotions more broadly through an improved understanding of the conditions and processes by which specific emotions, both adaptive and maladaptive, are elicited. Beyond the broader benefits to society to accrue from an increased understanding of emotional functioning, the proposed research will be conducted so to maximize its educational benefits. The scientific training of both undergraduate and graduate students will be advanced through their participation in data collection, analysis, and presenting the research at scientific meetings, as well as by participating in seminars that examine the theoretical underpinnings of this research.

0732983 - Vernet, Maria - Scripps Institute of Oceanography
0732450 - Van Dover, Cindy - Duke University
0732711 - Smith, Craig - University of Hawaii
0732917 - McCormick, Michael - Hamilton College

Collaborative Research in IPY: Abrupt Environmental Change in the
Larsen Ice Shelf System, a Multidisciplinary Approach - Marine
Ecosystems.

A profound transformation in ecosystem structure and function is occurring in coastal waters of the western Weddell Sea, with the collapse of the Larsen B ice shelf. This transformation appears to be yielding a redistribution of energy flow between chemoautotrophic and photosynthetic production, and to be causing the rapid demise of the extraordinary seep ecosystem discovered beneath the ice shelf. This event provides an ideal opportunity to examine fundamental aspects of ecosystem transition associated with climate change. We propose to test the following hypotheses to elucidate the transformations occurring in marine ecosystems as a consequence of the Larsen B collapse: (1) The biogeographic isolation and sub-ice shelf setting of the Larsen B seep has led to novel habitat characteristics, chemoautotrophically dependent taxa and functional adaptations. (2) Benthic communities beneath the former Larsen B ice shelf are fundamentally different from assemblages at similar depths in the Weddell sea-ice zone, and resemble oligotrophic deep-sea communities. Larsen B assemblages are undergoing rapid change. (3) The previously dark, oligotrophic waters of the Larsen B embayment now support a thriving phototrophic community, with production rates and phytoplankton composition similar to other productive areas of the Weddell Sea. To document rapid changes occurring in the Larsen B ecosystem, we will use a remotely operated vehicle, shipboard samplers, and moored sediment traps. We will characterize microbial, macrofaunal and megafaunal components of the seep community; evaluate patterns of surface productivity, export flux, and benthic faunal composition in areas previously covered by the ice shelf, and compare these areas to the open sea-ice zone. These changes will be placed within the geological, glaciological and climatological context that led to ice-shelf retreat, through companion research projects funded in concert with this effort. Together these projects will help predict the likely consequences of ice-shelf collapse to marine ecosystems in other regions of Antarctica vulnerable to climate change. The research features international collaborators from Argentina, Belgium, Canada, Germany, Spain and the United Kingdom. The broader impacts include participation of a science writer; broadcast of science segments by members of the Jim Lehrer News Hour (Public Broadcasting System); material for summer courses in environmental change; mentoring of graduate students and postdoctoral fellows; and showcasing scientific activities and findings to students and public through podcasts.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study will evaluate the safety and efficacy of islet after kidney transplantation (IAK) in patients with type 1 diabetes. Patients must have previously received successful renal transplant with stable immunosuppression consisting of sirolimus, tacrolimus and no corticosteroids and be referred by a transplant nephrologist/surgeon. Islets will be transplanted intraportally. Patients will be monitored closely for two years for the occurrence of adverse events and changes in renal graft function, blood glucose control, insulin dose requirements, other metabolic variables, immunologic reactions and quality of life. Islet transplantation is expected to improve glycemic control and thereby improve the patient's renal graft function and quality of life.

Organic-rich habitat islands support specialized communities throughout natural ecosystems and often play fundamental roles in maintaining alpha and beta diversity, thus facilitating adaptive radiation and evolutionary novelty. Whale-bone and wood falls occur widely in the deep-sea and contribute fundamentally to biodiversity and evolutionary novelty; nonetheless, large-scale patterns of biodiversity, connectivity, and ecosystem function in these organic-rich metacommunity systems remain essentially unexplored.

The PIs propose a novel comparative experimental approach to evaluate bathymetric, regional, and inter-basin variations in biodiversity and connectivity, as well as interactions between biodiversity and ecosystem function, in whale-bone and wood-fall habitats at the deep-sea floor. Their experiments will use bottom landers to carry and hold samples of bone and wood and a control substrate (basalt) at two depths (1500 and 3000 m), 250-500 km apart, in the NE Pacific and SW Atlantic basins, with quantitative recovery of the colonizing assemblages 15 month later. Each depth will have three replicates. Their experiments will test fundamental hypotheses concerning biodiversity (genetic and taxonomic) and biogeography of macrofaunal and microbial organisms exploiting these resource-rich habitats in energy limited deep-sea environments, and will explore the utility of whale-bone and wood falls as model experimental systems to address patterns of connectivity and decomposer function in the deep sea.

The project will have broader impacts in five areas: (1) At least two graduate students will conduct Ph.D. research, and three undergraduate students will participate in research cruises and develop senior theses within the project. (2) Project results will be incorporated into undergraduate and graduate courses at two universities. (3) The PIs will develop and deliver a new a graduate-level summer course at Friday Harbor Laboratory entitled Deep-Sea Biodiversity, Connectivity and EcosystemFunction based on project results. A similar course will be offered at the University of Sao Paulo in Brazil at no cost to NSF. (4) Public outreach will include project web sites and cruise blogs at both the University of Hawaii (UH) and Auburn University, and presentations at UH and Auburn open houses. (5) Results will be presented at conservation forums such as the annual meeting of Pew Fellows in Marine Conservation.

Intellectual Merit:
The PI requests support to analyze sediments from multi-cores and mega-cores previously collected from beneath the former Larsen B and Larsen A ice shelves. These unique cores will allow the PI to develop a time-integrated understanding of the benthic response to ice shelf collapse off the East Antarctic Peninsula over time periods as short as 5 years following ice shelf collapse up to >170 years after collapse. High latitudes are responding to climate change more rapidly than the rest of the planet and the disappearance of ice shelves are a key manifestation of climate warming. The PI will investigate the newly created benthic environments and associated ecosystems that have resulted from the re-initiation of fresh planktonic material to the sediment-water interface. This proposal will use a new geochemical technique, based on naturally occurring 14C that can be used to assess the distribution and inventory of recently produced organic carbon accumulating in the sediments beneath the former Larsen A and B ice shelves. The PI will couple 14C measurements with 210Pb analyses to assess turnover times for sedimentary labile organic matter. By comparing the distributions and inventories of labile organic matter as well as the bioturbation intensities among different locations as a function of time following ice shelf collapse/retreat, the nature and timing of the benthic response to ice shelf collapse can be assessed.

Broader impacts:
This study will provide important information characterizing changes occurring on the seafloor after the collapse of ice shelves. This research will support the research project of a graduate student. This project brings together researchers from both the European community and the LARISSA Project.

Marine communities along the western Antarctic Peninsula are highly productive ecosystems which support a diverse assemblage of charismatic animals such as penguins, seals, and whales as well as commercial fisheries such as that on Antarctic krill. Fjords (long, narrow, deep inlets of the sea between high cliffs) along the central coast of the Peninsula appear to be intense, potentially climate sensitive, hotspots of biological production and biodiversity, yet the structure and dynamics of these fjord ecosystems are very poorly understood. Because of this intense biological activity and the charismatic fauna it supports, these fjords are also major destinations for a large Antarctic tourism industry. This project is an integrated field and modeling program to evaluate physical oceanographic processes, glacial inputs, water column community dynamics, and seafloor bottom community structure and function in these important yet little understood fjord systems. These Antarctic fjords have characteristics that are substantially different from well-studied Arctic fjords, likely yielding much different responses to climate warming. This project will provide major new insights into the dynamics and climate sensitivity of Antarctic fjord ecosystems, highlighting contrasts with Arctic sub-polar fjords, and potentially transforming our understanding of the ecological role of fjords in the rapidly warming west Antarctic coastal marine landscape. The project will also further the NSF goal of training new generations of scientists, providing scientific training for undergraduate, graduate, and postdoctoral students. This includes the unique educational opportunity for undergraduates to participate in research cruises in Antarctica and the development of a novel summer graduate course on fjord ecosystems. Internet based outreach activities will be enhanced and extended by the participation of a professional photographer who will produce magazine articles, websites, radio broadcasts, and other forms of public outreach on the fascinating Antarctic ecosystem.

This project will involve a 15-month field program to test mechanistic hypotheses concerning oceanographic and glaciological forcing, and phytoplankton and benthic community response in the Antarctic fjords. Those efforts will be followed by a coupled physical/biological modeling effort to evaluate the drivers of biogeochemical cycles in the fjords and to explore their potential sensitivity to enhanced meltwater and sediment inputs. Fieldwork over two oceanographic cruises will utilize moorings, weather stations, and glacial, sea-ice and seafloor time-lapse cameras to obtain an integrated view of fjord ecosystem processes. The field team will also make multiple shipboard measurements and will use towed and autonomous underwater vehicles to intensively evaluate fjord ecosystem structure and function during spring/summer and autumn seasons. These integrated field and modeling studies are expected to elucidate fundamental properties of water column and sea bottom ecosystem structure and function in the fjords, and to identify key physical-chemical-glaciological forcing in these rapidly warming ecosystems.

Worldwide publicity surrounding the calving of an iceberg the size of Delaware in July 2017 from the Larsen C Ice Shelf on the eastern side of the Antarctic Peninsula presents a unique and time-sensitive opportunity for research and education on polar ecosystems in a changing climate. The goal of this project is to convene a workshop, drawing from the large fund of intellectual capital in the US and international Antarctic research communities. The two-day workshop will be held at Florida State University where a consortium of researchers with expertise in Antarctic biological, ecological, and ecosystem sciences will be gathered to share knowledge, identify important research knowledge gaps, and outline strategic plans for research. The workshop will help advance scientific and public understanding of the continent-wide changes that Antarctic ice shelves and surrounding ecosystems experience as ice shelves change. The primary products will be reports focusing on synthesizing, coordinating and integrating research efforts to understand the ecological impacts of ice-shelf collapses and large iceberg calving along the Antarctic Peninsula. The workshop will also provide an immediate, interactive experience for K-12 school children with a hands-on ?Saturday Polar Academy?, a children's poster session, and question-answer session during the workshop. Children will have the opportunity to interact with Antarctic researchers and become familiar with Antarctic science, organisms, ecosystems and current issues, feeding their scientific curiosity.

The calving of A-68, the 5,800 square kilometer iceberg shed in July 2017 from the Larsen C Ice Shelf presents a unique and time-sensitive research opportunity. The scientific momentum and public interest created by this most recent event will be leveraged to convene a workshop at the earliest opportunity, drawing from the large intellectual capital in the US and international Antarctic research communities. The two-day workshop will be held at Florida State University, Coastal and Marine Laboratory on the Gulf Coast organized by Jeroen Ingels (Florida State University; FSU), Richard Aronson (Florida Institute of Technology; FIT), and Craig Smith (University of Hawaii at Manoa; UHM). A consortium of researchers with a diversity of expertise in Antarctic biological, ecological, and ecosystem sciences will be gathered to share knowledge, identify important research priorities and knowledge gaps, and outline strategic plans to advance understanding of the continent-wide changes that Antarctic ice shelves and surrounding ecosystems experience as ice shelves change.

The abyssal plains of the oceans cover roughly half of the earth's surface, host enormous reservoirs of biodiversity and mineral resources, and play important roles in nutrient recycling and carbon sequestration. The most important process controlling the structure and function of these ecosystems is the quantity and quality of food (mostly sinking organic particles) that reaches the deep-sea floor. However, we do not fully understand the processes provisioning this vast ecosystem. We propose to evaluate the relative importance of small and larger "marine snow" particles that sink to deep-sea benthic communities by using the stable isotope signature of amino acids within various food sources and trace their consumption by fauna on the seafloor. This project compares ecosystems from the productive waters off California with the nutrient poor central Pacific, north of Hawaii. This project provides novel insights into how surface ocean processes are coupled to food-webs at the deep ocean seafloor and how changes in food sources potentially impact deep-sea communities. This project also provides excellent training opportunities for graduate students, a postdoctoral researcher, and undergraduates at UH and USC, particularly underrepresented minorities who pursue majors in the geosciences. The project will sponsor an annual G6-12 teacher workshop to inform Hawaii educators about the deep sea and broadly disseminate knowledge to the community. All results are communicated broadly to inform the public as concerns regarding abyssal ecosystems are rising due to interests in deep-sea mining.

The most important process controlling the structure and function of abyssal ecosystems is the quantity and quality of organic material that ultimately reaches the deep-sea floor. Despite the strong relationship between euphotic zone export flux and benthic ecology, studies of abyssal ecosystems have observed a deficit between food supply and benthic community demand. Additional work is therefore needed, particularly with regards to understanding the sources of nutrition to the deep-sea benthos. Recent evidence suggests that small particles may be significant contributors to carbon export, increasing in relative importance with depth in the mesopelagic and reaching the abyssal seafloor. This project is to evaluate the relative importance of small and larger "marine snow" particles to deep-sea benthic communities using a combination of particle flux measurements and state of the art compound specific stable isotope analysis of amino acids (AA-CSIA) at two abyssal locations that contrast in overlying productivity, seasonality, and export magnitude. Time series measurements at these locations (Sta. M off California and Sta. Aloha off Hawaii) provide a rich context for the work. In the mesopelagic central North Pacific larger particles (>53 um) can be resolved from microbially reworked, smaller (0.7-53 um) particles using AA-CSIA. This project is characterizing the isotopic compositions of key individual compounds in a continuum of particle sizes (< 1.0 um suspended particles to large sinking particles >53 um) collected using in situ filtration near the seafloor and bottom-moored sediment traps, thereby defining source-specific isotopic signatures that can be traced into benthic fauna and sediments (that are collected by ROVs and epibenthic sleds). This research to understand pelagic-benthic coupling from particles to megafauna using isotopic measurements at the compound-level will yield novel insights into the importance of small microbially reworked particles to deep-sea benthic food webs. This will more precisely couple surface ocean processes to food-webs at the deep ocean seafloor with implications for understanding climate change effects and the efficiency of energy transfer to higher trophic levels. Furthermore, isotopic measurements can also be used to further parameterize ecosystem models by quantifying trophic position across size classes and thus estimate predator-prey mass ratios in relation to variation in body size spectra, functional type, and ultimately to carbon flux and remineralization. Finally, the results will help refine interpretations of deep-sea paleorecords of past nitrogen dynamics by calibrating potential changes in organic matter isotope values between the surface and seafloor archives.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.