Robert M. Sherrell - US grants

Study will be made of trace element scavenging mechanisms and particle dynamics through measurements of temporal variations in dissolved, suspended particulate and sinking particulate elemental distributions during a two year time-series study in the northeast Pacific. A recently-developed in situ pump will be used for collection of contamination-free size-fractionated samples of suspended matter throughout the water column. Five occupations of a deep-water station in the California Current will sample three seasons of varying productivity. This sampling will be coupled with simultaneous sediment trap and dissolved element measurements to examine the effect of changing productivity and vertical mass flux on the overall distribution of trace elements in a productive eastern boundary water column. Samples of all three pools will be analyzed for Al, Fe, Ca, Si, Mn, Pb, Zn, Cu, Ni, Cd, Ba, I, U, and 232Th. This research will address the shortage of fundamental information on the distribution of particulate trace elements which currently limits formulation of realistic scavenging models. The chemical differences in the behavior of elements will be used as probes of the scavenging process, as illustrated by our previous measurements of a subset of these elements in samples from Bermuda, the Northeast Atlantic, and the Northeast Pacific. In addition, elemental composition of particulate matter will be used as a tracer of mass exchange among particulate pools.

This research is a new and detailed approach to the investigation of chemical scavenging processes in the Atlantic and Pacific Oceans, using the distributions of the rare earth elements (REE) as indicators of particulate removal and redox cycling under varying conditions of primary particle flux and water column structure. In situ pumping, will be used to collect large suspended particulate samples as part of an ongoing study of dissolved/particulate fractionation for a suite of major and minor elements. Established trace metal seawater sampling techniques will be used to collect REE water samples. The dependence of dissolved and particulate REE patterns and cerium anomalies on the mass concentration, composition, and vertical flux of the suspended particle field will be explored. This will be accomplished by profile measurements at four oceanographically distinct sites: 1) the productive Northeast Pacific margin environment, 2) the oligotrophic Northeast Atlantic, 3) the Gulf Stream/NW Sargasso Sea frontal system, and 4) the variably productive Central Equatorial Pacific. The REE will be used as probes of scavenging processes over spatial and temporal gradients in primary and new production. Results will have broad implications for the critical variables which regulate biological uptake, adsorptive scavenging, and redox-controlled removal of trace inorganics in open ocean and ocean margin environments.

9311080 Able, K. The Rutgers University Marine Field Station is located near Tuckerton, New Jersey, at the mouth of the Mullica River - Great Bay Estuary. The entire watershed of this estuary is protected within the New Jersey National Pinelands Reserve. The station provides easy access to extensive salt marsh and estuarine habitats in the cleanest estuary on the northeast coast, and to a site at 15 m depth on the continental shelf where studies on hydrodynamic processes, sediment resuspension and transport, larval and juvenile settlement and recruitment of commercial species of fish and invertebrates, and bottom boundary layer prosses affecting benthic communities are being conducted. A Long-Term Ecosystem Observatory has been established at this site to track episodic and long-term changes in important environmental parameters. This project will 1) enhance the ability to transport and maintain invertebrates and fishes from the estray and continental shelf under controlled temperatures, and 2) improve data collection at the site on environmental factors fundamental to a number of the studies there, e.g., additional components for an existing meteorological station, a salinometer and a fluorometer. ***

9316183 Sherrell PIs have found iridium (Ir) anomalies in ice cores associated with the 1908 Tunguska event and the 1783 Laki eruption. In collabooration with Robert Rocchia (Paris), they will extend these analyses to other ice cores with the following goals: 1) test and verify findings, 2) make systematic studies on ice core samples to clarify partitioning of Ir, and 3) investigate temporal variability of background Ir deposition. Results have implications for debate over impact vs. volcanic sources for iridium in the stratigraphic record, and also for linking volcanism and impacts to climatic changes.

9601668 Sherrell Funds are provided to Rutgers University for acquisition of an Isotope Ratio Mass Spectrometer (IRMS) and an Inductively-Coupled Plasma Mass Spectrometer (ICP-MS) which will be utilized for integrated and interdisciplinary studies of coastal biogeochemistry. The IRMS will allow the determination of stable isotope ratios of carbon, nitrogen, sulfur, and oxygen in samples of sea water, particulate organic matter, and plant and animal tissue. The ICP-MS will permit rapid sensitive analysis of a suite of elements which act as important tracers of pathways within biogeochemical cycles in the marine environment. Both mass spectrometers will be managed by faculty working groups in user groups, and the instruments will be run on a cost per sample basis. Rutgers University is supporting this project with $316,000, which represents a 44% costshare. ***

9601668 Sherrell Funds are provided to Rutgers University for acquisition of an Isotope Ratio Mass Spectrometer (IRMS) and an Inductively-Coupled Plasma Mass Spectrometer (ICP-MS) which will be utilized for integrated and interdisciplinary studies of coastal biogeochemistry. The IRMS will allow the determination of stable isotope ratios of carbon, nitrogen, sulfur, and oxygen in samples of sea water, particulate organic matter, and plant and animal tissue. The ICP-MS will permit rapid sensitive analysis of a suite of elements which act as important tracers of pathways within biogeochemical cycles in the marine environment. Both mass spectrometers will be managed by faculty working groups in user groups, and the instruments will be run on a cost per sample basis. Rutgers University is supporting this project with $316,000, which represents a 44% costshare. ***

ABSTRACT

OCE-9819324 / OCE-9902660 / OCE- 9902658


Although a number of recent studies have verified that primary production in various marine environments may be limited by trace metal availability, there has not yet been a similar body of research for freshwater systems, even the inland sea system of the North American Great Lakes. In this project researchers from the University of Minnesota, Rutgers University, and Bowling Green State University will investigate the existence, mechanisms, spatial-temporal extent, and significance of trace metal limitation to primary production in Lake Superior. They will take a three-pronged approach. First, to quantify and characterize total and bioactive trace metal concentrations, Al, Fe, Mn, Zn, Cu, Cd, and Co would be determined in solution, in suspended particles, and in plankton in the field. Secondly, immunological and fluorescence assays would be used to assess metal deficiency in algae in the field. Third, trace metal enrichment experiments would be used to assess limitation experimentally in the laboratory. The three field sites would be chosen to take advantage of existing data available from the NSF-sponsored KITES program.

The overall objective of this project is to investigate iron limitation in marine phytoplankton using the newly discovered fluorescence diagnostic technique. The project encompasses both laboratory and field components. The laboratory studies are aimed at resolving the physiological mechanism(s) for the fluorescence diagnostic of iron limitation and testing for its expression across major phytoplankton taxonomic divisions. These studies are based on continuous culture experiments and will include measurements of. (1) variable fluorescence parameters, (2) fluorescence emission spectra, (3) picosecond fluorescence lifetimes, and (4) the stoichiometric composition of the photosystems. The laboratory studies will address the following questions:

(1) Does the fluorescence diagnostic result from an effect of iron limitation on the fluorescence signature of state transitions or the back-transfer of electrons from a highly reduced plastoquinone pool to the primary acceptor on Photosystem II?

(2) Is the fluorescence diagnostic equally expressed in all taxonomic divisions under iron limiting conditions or is it restricted to prokaryotic photoautotrophs?

The modest field component will be conducted to explore the utility of this technique in nature.

This project details the development of a new course in quantitative analysis that is designed to capture the imagination and interest of chemistry majors and of larger numbers of students of environmental and biological sciences. The revised course will improve students' preparation for independent research opportunities with faculty mentors.

The project is to implement work from "The Chemistry of Water" (NSF DUE 9156123). The primary object is to enable students to: 1) receive training in analytical chemistry that is current, level-appropriate, and of the highest quality; 2) see how their own laboratory results relate to an ongoing scientific investigation and thus how scientific knowledge advances through collation of independent data sources; 3) gain mastery over the internet's power to facilitate the sharing of data; and 4) work on assignments that take account of their varied learning styles. Successful innovations and modifications will be shared with the larger community of chemical and environmental educators.

A working group of faculty members from the Departments of Chemistry, Marine and Coastal Sciences, Environmental Sciences, and Biochemistry has devised means to obtain for students a set of oceanographic samples with research significance. Students will analyze these samples in many different ways and compare their results with those obtained by active research scientists. New experiments will be designed by project investigators knowledgeable in instrumental chemical oceanography (NSF BES 9402540); trace element analyses (NSF OCE 9601668; NSF EAR 9316242); and analytical techniques related to phytoplankton pigmentation (NSF OCE 9402540). The organization of the group laboratory activities will be based partly on the ideas of P.M. Treichel and colleagues (NSF DUE 9450615) and will also be influenced by experience gained in connection with a course on the Greenhouse Effect (NSF DUE 9354742), and a program recently begun at Rutgers for Institution-Wide Reform of Education in Science, Mathematics, Engineering, and Technology (NSF DUE 9850071).

The proposed innovations will affect a diverse group of undergraduates. Current enrollment demographics indicate that an appropriate audience is being and will be reached. (e.g., Fall 1998: 50% male, 50% female; 10-15% latino; 5-10% African-American). The revised course will rely on the use of the web for distribution of course materials and for transfer of data among students and from the web site for Rutgers' Long-term Ecosystem Observatory.

In this study, the PIs will test and develop a new paleoclimate proxy- Rare Earth Element (REE) abundances of carbonate sediments that contain metalliferous sediment originating from hydrothermal plumes. In combination, the PIs will use Nd isotope values (?Nd) as a proxy to help unravel differences in weathering rates and sources from variations in seawater REE abundances due to other causes. The short residence times of the REE (<1-4 Ka) mean that potentially, these proxies could provide high resolution data. Preliminary data show that metalliferous sediment records bottom water REE patterns and that the REE patterns are virtually identical for the Atlantic and Pacific. The entire REE pattern is reflected in differences in Nd/Er. Preliminary data for a core for the last 135 Ka indicate that Nd/Er and ???O are well correlated, showing good potential for the proxy. Additional preliminary data for a longer period (last 28Ma) show interesting patterns and large changes in ?Nd and Nd/Er for this period, again arguing that these combined proxies have potential to identify changing weathering inputs to the ocean. In order to further evaluate this proxy, the PIs will analyze hydrothermal plume material from additional hydrothermal vents in the northern and southern EPR, carry out lab experiments of REE uptake in vitro, calibrate the Nd/Er proxy using Holocene core tops from SEPR cores, evaluate possible diagenetic effects on the preservation of the proxy signals using cores with known and diverse diagenetic histories, and explore the behavior of both proxies on Ma to 10 Ka time scales for large climatic variations in the Oligocene and Miocene.

ABSTRACT

OCE-0137592


In this project, researchers at Rutgers University will continue their ongoing studies of the dependence of cadmium uptake by coastal marine phytoplankton on taxonomic affinity, growth rate, relative concentrations of other bioactive metals, and the ambient dissolved concentration of carbon dioxide in seawater. With this renewal funding, the focus will be on laboratory culture studies to complement field work carried out over the last four years. Anticipating that the implications of the study will be of general applicability, the investigators have designed the study to quantify fundamental dependencies for several classes of phytoplankton. Nevertheless, a strong impetus for the work is the desire to understand cadmium/phosphorous fractionation in Southern Ocean surface waters. The team hopes to develop ground rules for the robust estimation of phosphorous utilization in past Southern Ocean surface waters from the Cd/Ca ratio of fossil planktonic foraminifera.

The three-year project will address two major questions: (1) Does uptake of Cd depend strongly on phytoplankton phylogeny, or are cell size, growth rate and availability of other metals more important? (2) Is increased Cd uptake with decreased pCO2 found in all major phytoplankton groups, or just diatoms, and is it caused by a physiological response to pCO2 or by pH-dependent changes in water chemistry? To answer these questions the research team will conduct two sets of experiments. First, they will determine Cd uptake in phytoplankton species from four major taxonomic groups, and test the dependence of Cd uptake on availability of other bioactive metals and on growth rate. Secondly, they will investigate the mechanism and ubiquity of Cd uptake control by ambient dissolved CO2 concentration by measuring the effect of varying CO2 on species across a wide phylogenetic spectrum of the phytoplankton. As part of the latter studies, they will conduct experiments to distinguish a physiological role for Cd in carbon acquisition from pH effects on availability of competing metals.

ABSTRACT
OCE- 0352291 / OCE- 0352274 / OCE 0352208

The concentration of nitrate in Lake Superior waters has increased steadily during the past century by six-fold from ca. 5 to ca. 30 umol L-1. Today, nitrate remains in excess of biotic demand at the end of the growing season. Though the increase in nitrogen concentration is not surprising, the magnitude and rate of increase in Lake Superior are, considering the long, fifty-year N turnover rate of the lake, and the absence of significant local sources of N to the mainly forested watershed.

To elucidate the causes of this impressive nitrate build up, researchers from the University of Minnesota, Bowling Green State University, and Rutgers University will undertake studies of the Lake Superior nitrogen cycle, combined with studies of limiting nutrients and the responses of plankton communities to differing nutrient supply regimes. Nitrification and denitrification rates, previously assumed to be zero, will be measured with stable isotope tracers and with other methods. Sources and transformations of the lakes nitrate will be traced using natural abundances of stable isotopes of nitrogen and oxygen in the lake, in streams and rivers, and in atmospheric sources. In addition to testing the limitation on nitrate uptake, the team of scientists will also explore the N cycle and its intersection with the P and Fe cycles in this large lake. Shortages of P, along with cold and dark physical conditions, are likely important factors in understanding lack of ecosystem assimilation of added nitrate. Iron too may play an important role because of its critical role in nitrate utilization by plankton. Indeed, it may be that absence of iron limits the ability of the plankton to utilize nitrate such that the plankton are N deficient even in the presence of nitrate surplus. In addition to developing a new water column nitrogen model and data sets for several geochemically distinct pools of dissolved P and Fe (with both spatial and temporal coverage of large portions of the lake) this research will also yield a dramatically improved knowledge of the nitrogen cycle in the worlds' largest lake.

0420839
Sherrell
This Major Research Instrumentation award to Rutgers University in New Jersey provides funds for acquisition of a high-resolution inductively coupled plasma-mass spectrometer for research and teaching at the Institute of Marine and Coastal Sciences and the Department of Geological Sciences. The award includes support for a laser ablation sample introduction system. In addition to marine and earth sciences applications, it is expected that use will include a wide array of environmental and health sciences research, as has been the case with the system it will replace. The broader impacts of the acquisition include a major emphasis on education and training at a number of levels, from student internships through methods courses for researchers. In addition the instrumentation will be managed as a shared-use facility, open to researchers from throughout Rutgers and outside, and it will be used to study a wide array of projects with compelling societal relevance (climate change, pollution, erosion). Rutgers is providing cost-share of 30% of the project cost from non-federal funds. This proposal is supported by the Division of Ocean Sciences at NSF.
***

Abstract

The research objective is (1) to determine the distributions and dynamics of a full suite of bioactive trace metals in dissolved and suspended particulate forms, along sampling transects of the Amundsen and Ross Seas. And (2) to test the sensitivity of overall cellular metal stoichiometry (metal/carbon ratios) to natural gradients in species assemblage and Fe availability. Our earlier findings from a single Ross Sea station and from a Drake Passage crossing suggest that Fe-limited phytoplankton cells are unusually enriched in Zn, Cu and Cd relative to biomass carbon, with strong implications for the biogeochemical cycling of these elements relative to carbon fluxes in the Southern Ocean. In collaboration with other researchers on the cruise, we will also measure metal stoichiometry of cells exposed to predicted 2010 temperature and carbon dioxide levels in shipboard incubation studies, as a window into possible effects of climate change on metals biogeochemistry in these regions. This proposal will support close international collaborations and lasting infrastructure development as US and Swedish scientists, and more importantly, their students, work toward shared the shared goal of understanding a region that is experiencing one of the fastest rates of climate change on the globe. Trace metal micro-nutrients are a key control on the productivity of Antarctic marine ecosystems. Our results will be made widely available through research publications and internet-available databases, and public outreach through COSEE at Rutgers University.

Oceanic trace elements and their isotopes can function as nutrients, contaminants, and tracers or proxies of various oceanographic processes. The GEOTRACES program was developed as an international initiative designed to determine the processes that control the global distributions and biogeochemical cycles of key trace elements and their isotopes (TEI) throughout the ocean. Laboratories and institutions from around the world will be involved in completing sampling transects across ocean basins to achieve the scientific objectives of GEOTRACES. However, before performing ocean transects, intercalibration of sampling, analytical, and modeling techniques must be completed to attain the best precision and accuracy for the GEOTRACES program.

Oceanographers from Old Dominion University, the University of California in Santa Cruz, and Rutgers University proposed to provide the infrastructure and organization required to support the participation by as many U.S. and international scientists as possible. The principle investigators specifically propose to address the U.S. GEOTRACES intercalibration through development and testing of the U.S. GEOTRACES sampling systems and procedures for TEIs. Using these systems, the principle investigators intend to conduct a thorough intercalibration for the dissolved and particulate phases of the GEOTRACES TEIs and establish GEOTRACES Baseline Stations in the western North Atlantic and eastern North Pacific Oceans. These results would be documented and utilized to create the "US GEOTRACES Users Manuals and Procedures" for future US-sponsored GEOTRACES cruises.

The development of a GEOTRACES infrastructure is significant in impact to both the oceanographic and public community. The development of users' manuals will be invaluable to scientists in the US and to those in less-developed countries with few resources to devote to basic oceanographic research. By completing the first phase of the GEOTRACES initiative, the oceanographic community will have a better understanding of the processes involved in oceanic trace-element cycles and their sensitivity to changing environmental conditions.

A direct record of past nutrient concentrations in the surface ocean would add considerably to our understanding of the links between ocean circulation, climate, and air-sea carbon fluxes, and in coastal waters would allow reconstructions of upwelling and eutrophication histories. The calcium carbonate skeleton of a single colony of coral can provide a continuous record of ocean surface conditions, including phosphate concentrations, over hundreds of years. For this reason, an investigator from Rutgers University plans to develop, calibrate, and apply a new coral proxy for surface ocean phosphate based on promising preliminary data from a Gulf of Panama coral indicating skeletal P/Ca quantitatively record variations in surface water phosphate in a seasonal upwelling regime. This project will focus on calibration of the P/Ca proxy against in situ time-series surface water chemistry data, to test the following hypotheses based on findings from the preliminary data: (1) skeletal P/Ca in recent corals quantitatively reflects documented time-series surface water phosphate variations at relatively high (Panama Bay: 0.2-0.8 M) and low (Gulf of Eilat, Red Sea: 0.01-0.1M) seawater phosphate values; (2) the P/Ca surface water phosphate proxy can be applied in Pavona and Porites, and inter- and intra-colony replication would allow reconstruction of seasonal scale surface water phosphate variations; (3) coralline phosphorous is incorporated as a combination of inorganic and organic species that allow total P/Ca to be resistant to diagenetic alteration, permitting application of P/Ca to long cores and fossil corals; and (4) the organic component of skeletal phosphorous largely comprises phospholipids distributed at the sub-micron scale in biogenic aragonite and provide a window into incorporation mechanism.

As regards broader impacts, the scientist would collaborate with the COSEE-MA office at Rutgers University to develop coral and paleoceanography teaching materials. One graduate student would be supported and trained as part of this project.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

The Amundsen Sea Polynya is areally the most productive Antarctic polynya, exhibits higher chlorophyll levels during peak bloom and greater interannual variability than the better-studied Ross Sea Polynya ecosystem. Polynyas may be the key to understanding the future of polar regions as their extent is expected to increase with anthropogenic warming. The project will examine 1) sources of iron to the Amundsen Sea Polynya as a function of climate forcing, 2) phytoplankton community structure in relation to iron supply and mixed-layer depths, 3) the efficiency of the biological pump of carbon to depth and 4) the net flux of carbon as a function of climate and micronutrient forcing. The research also will compare results for the Amundsen Sea to existing data synthesis and modeling efforts for the Palmer LTER and Ross Sea. The project will 1) build close scientific collaborations between US and Swedish researchers; 2) investigate climate change implications with broad societal relevance; 3) train new researchers; 4) encourage participation in research science by underrepresented groups, and 5) involve broad dissemination of results via scientific literature and public outreach, including close interactions with NSF-supported PolarTrec and COSEE K-12 teachers

Reconstruction of nutrient concentrations in past intermediate and deep waters is a critical goal in paleoceanography. Such information will allow calculation of intermediate/deep water mass mixing ratios in areas of active advection (e.g., the Atlantic), and when combined with radiocarbon dating will yield ventilation rates, which are thought to be an important control on atmospheric CO2. Past nutrient distributions can also yield information about productivity and remineralization in areas of more sluggish circulation. This award supports refinement and application of paleo-proxies for the nutrient phosphate (P/Ca) and the quasi-nutrient barium (Ba/Ca) in the solitary deep-sea coral D. dianthus. The research will produce a regional proxy calibration for the Southern Ocean using live-collected corals, and will then analyze fossil specimens to determine the evolution of endmember Southern source water nutrient content since the Last Glacial Maximum. They will also reconstruct the history of nutrient concentrations at mid to deep water depths in the NW Atlantic over the past 30ky using dated fossil corals from the New England seamounts. The research will provide a new, quantitative assessment of nutrient distribution in the past ocean. This work is part of a larger collaborative effort involving scientists from CalTech and Imperial College, London, who will provide both sample material and complementary data. Broader impacts include funding of a female PhD student as well as outreach efforts in association with the well-established COSEE (Center for Ocean Sciences Education Excellence) program at Rutgers University.

Ocean acidification (the decrease in seawater pH) is driven by the increase in atmospheric CO2. This is expected to have a dramatic effect on organisms that precipitate calcium carbonate. Coral reefs are formed and maintained by calcifying organisms, particularly reef-building corals. Current predictions are that coral species will be negatively impacted; however the limited number of available measurements exhibit significant variability for reasons that are not understood. This is critically important as coral reef ecosystems hold significant cultural and economic values both nationally and internationally. This program is therefore focused on the molecular basis for calcification in corals in order to understand how corals will respond to ocean acidification in the next century. Rutgers University has a state-of-art coral culture facility that will be used to simulate future ocean conditions. The work will utilize a unique set of coral tissue cultures that will allow scientists to assess the cellular biology that underlies the reponses of corals to ocean acidification. The laboratory measurements will also determine how geochemical signatures of corals are affected by varying environmental conditions. These results are important because coral geochemical signatures are used to understand how corals have responded to changes in the ocean pH in the historical past. The project will be conducted by a research team at Rutgers, in collaboration with scientists in Taiwan and Israel. The program will also engage K-12 teachers in order to develop lesson plans that highlight coral biology and ocean biogeochemistry.

This project seeks to generate a Uranium/Thorium (U/Th) dated record of rainfall in the southern tropical Pacific at sub-century (~50 year/sample) resolution for most of the glacial and Holocene periods using stalagmites from the island of Niue and from Tonga. The speleothem from Niue dates to 83,000 years before the present.

Specifically, the researchers will: 1) analyze the Niue specimen, as well as a Holocene-age stalagmite from Tonga, for Oxygen-18, Carbon-13, Magnesium/Calcium ratios, Strontium/Calcium ratios, and Barium/Calcium ratios; 2) generate a precise absolute-dated U/Th age model for the specimens; and 3) undertake drip-water sampling to validate paleoclimate interpretations.

The goal of the project is to examine the following hypotheses: a) at times of increased Thermohaline Circulation (THC), a northward shift of the Pacific Inter-tropical Convergence Zone (ITCZ) dominated over a westward shift in the Walker Cell resulting in decreased rainfall at Niue; and b) rainfall records at Niue will show rapid shifts in phase with Greenland ice-core records, but will also show additional changes characteristic of Antarctic temperature records.

The broader impacts include the potential for a high-quality paleoclimate record from an important and under-studied region. In addition to the scientific importance and support of a graduate student, the researcher will conduct outreach through a NSF-sponsored program through which high-school students and teachers from New Jersey participate in workshops on marine and climate science.

The shelf waters off the Western Antarctic Peninsula characteristically show high primary productivity, yet are bounded to the west and north by an apparently iron limited Antarctic Circumpolar Current. Natural sources of bioavailable Fe amendments are thought variously to arise from atmospheric deposition, upwelled Circumpolar Deep Water shoaling over the continental shelf, glacier and iceberg melting or even inputs from underlying shallow shelf sediments. As part of the ongoing Palmer LTER (Long-Term Ecological Research) program, a comprehensive study of the water column distribution, bio-uptake studies and the dynamics of various forms of Fe and other bioactive elements will be used to inform physical and biogeochemical models of the WAP.

The Western Antarctic Peninsula is a region of recent rapid climate change and also an important time series site for monitoring carbon uptake from the atmosphere, by the polar ocean. How ecological processes currently being studied in the context of the Palmer LTER site are adapting to a warming ocean is of interest to the science education community, the public, and society at large on issues ranging from the health of the oceans to global sea level rise.

During the 2013 GEOTRACES Eastern Pacific cruise a diverse range of oceanic environments will be encountered from the high productivity/high particle flux waters off Peru to the Peru-Chile oxygen minimum zone, the hydrothermal plume of the East Pacific Rise, and finally to some of the most oligotrophic waters around Tahiti. Scientists from Rutgers University and Woods Hole Oceanographic Institution will sample suspended particulates from the same GO-Flo bottles that will be used to sample dissolved trace metals and their isotopes (TEIs) across this entire transect. The suspended matter samples will be analyzed for 42 elements, including the particle-reactive rare earth elements. In addition, core-top sediments will be collected at every water-column sampling station and analyzed for both bulk composition (i.e., relative % content of organic carbon, opal, biogenic carbonate and lithogenic components) and the same 42 elements to be analyzed in the suspended particulates. Results from this study will be used to assess the role of suspended particulates in the biogeochemical cycling of TEIs across the Eastern Pacific by addressing three key sets of questions: (1) How does uptake of TEIs into phytoplankton and non-living particles in the upper ocean drive the suspended particulate composition through the deeper water column, along the substantial gradient from the high productivity Peru margin to the oligotrophic ocean interior?; (2) How faithfully is the along-transect variability in the upper ocean transmitted to the sediment (paleo) record?; (3) What are the relative influences of vertical recycling versus lateral advection in generating the distributions of dissolved and particulate TEIs observed in the Peru-Chile OMZ?; (4) Is there a characteristic signature of OMZ activity that is preserved in core-top sediments?; (5) What dominates TEI uptake onto/into authigenic particles in hydrothermal plumes and to what extent are these processes augmented by continuing uptake in core-top sediments?; and (6) What is the net effect from submarine venting on global TEI budgets?

As regards broader impacts, the scientist from Rutgers University is collaborating with the Education Director of the Centers for Ocean Science Education Excellence Networked Ocean World (COSEE-NOW) to contribute to the MARE (Marine Activities, Resources, and Education) program by inviting teachers and high school students to workshops and presentations on climate and ocean sciences. With the help of COSEE-NOW, he also plans to create educational video clips during the Pacific cruise and the subsequent laboratory based analytical work to educate them on the use of geochemistry to understand how the ocean works. Both scientists also plan to develop a teaching module entitled "Particles, Metals, and Carbon" for an Introduction to Oceanography class taught by the Rutgers scientist. One postdoc from Rutgers University would be supported and trained as part of this project.

In this project, investigators participating in the 2015 U.S. GEOTRACES Arctic expedition will measure the concentrations of iron, manganese, zinc, copper, cadmium, and nickel from a variety of seawater and ice samples in the Western Arctic Ocean. These are commonly referred to as 'micronutrients' because they are present in the ocean in extremely low concentrations and because they are essential for marine organisms. In common with other national initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. The six trace elements to be measured in this study are arguably the most important bioactive trace elements in the oceans, and their measurement will provide key information on biological and physical processes in the Arctic. This project will be carried out under the direction of a postdoctoral researcher, providing a unique professional development opportunity for an early career scientist. In addition, the research will involve the training of an undergraduate researcher, and provide public outreach opportunities to K-12 teachers and students, and indigenous populations in Alaska.

The six micronutrients to be measured under this project have all been identified as key trace elements for the GEOTRACES Program. This research will allow rigorous testing of the Arctic physical and biological processes, many of which are already undergoing fundamental changes as a result of climate change, that control the inputs and fate of key micronutrient metals in the Arctic Ocean. Colloidal distributions are specifically targeted in order to derive additional information on the unique physicochemical form and reactivity of distinct dissolved metal pools. The project will also explore the role of melting sea ice in driving near-surface concentrations of these elements by measuring concentrations and size partitioning of these six metals in sea ice, snow, melt ponds, and in the seawater immediately under sea ice. Given that the Arctic is a relatively small basin surrounded by broad continental shelves, sedimentary sources and sinks will also play a major role in controlling the distributions of these elements. Thus, metal concentrations in porewater samples from bottom sediments will also be determined from cores in the Bering and Chukchi Seas, in order to investigate benthic exchanges.

The Amundsen Sea, in the remote Pacific sector of the Southern Ocean, is one of the least well studied Antarctic continental shelf regions. It shares characteristics in common with other Antarctic ice shelf regions, but exhibits unique aspects also. The Amundsen Sea Polynya (ASP), an open region at the base of several of the terminal glaciers draining the West Antarctic Ice sheet exhibits: 1) large intrusions of heat delivered from the warming modified circumpolar deep water (mCDW) rising up onto the continental shelf, 2) the fastest melting ice sheets in Antarctica, 3) the most productive coastal polynya (161 g C m-2) together with a significant atmospheric CO2 sink, and 4) some of the most rapidly declining regions of seasonal off-shore sea ice on Earth.

Following on from an earlier oceanographic field program, the Amundsen Sea Polynya International Research Expedition (ASPIRE; 2011), this study seeks to better synthesize and model the relative contributions of both physical ocean-ice linkages and biological production and carbon export terms and to compare these with other circumpolar Antarctic regions. A central feature will be the use of a regionally coupled physical-biogeochemical model to follow the dynamics of the large phytoplankton blooms that occur annually in the Amundsen Sea Polyna. This study will provides a means to locate the Amundsen Sea properties along the continuum of Antarctic ice shelf systems, and to understand how these system might change in response to climate change.

Pedagogical techniques will be used to provide educational outreach for three distinct target populations: secondary students, pre-service science teachers, and in-service science teachers. Partnerships will be developed with science teacher educators to implement the STEM career-development lessons in undergraduate and graduate level science teacher
education courses.

Fundamental understanding of the geochemistry of the ocean is required to advance basic knowledge of the world we live in, and to reconstruct aspects of our past climate from the composition of ocean sediments and fossils. This work requires sophisticated instrumentation in a modern laboratory. This award provides the funding for a group of researchers at Rutgers University to purchase a new mass spectrometer (ICP-MS) and an associated laser ablation (LA) sample introduction system, so that they can continue their ongoing research into trace elements in seawater and ocean sediments, and to expand their measurements in new research directions. Our society is urgently interested in the role of the ocean in governing earth's climate; the research of the Principle Investigators will contribute to the fundamental understanding of physical, chemical and biological processes in the ocean that drive the exchange of carbon dioxide with the atmosphere. The new instruments will also be integrated fully into undergraduate and graduate teaching and research: (1) A combined undergraduate/graduate class entitled "Inorganic Mass Spectrometry for Earth Sciences" will be taught focusing on ICP-MS theory and practice; (2) The new facility will offer challenging opportunities for undergraduate research supported by Rutgers' Aresty, RISE, and the NSF Research Experiences for Undergraduates summer programs. In addition, the researchers will work with the new NSF-funded center Advancing the Impact of Research on Society (ARIS) to develop learning opportunities emphasizing participation in science. This project will be modeled on the NSF-funded Rutgers Polar-Interdisciplinary Coordinated Education (ICE) program, that has been successfully implemented in twenty-one classrooms across the country. A new educator course is currently being piloted and will be expanded and offered to a new cohort of educators interested in using scientific data in their teaching. The Principle Investigators have an established reputation for research that expands the capabilities of this type of instrumentation, and have trained many students, including many women and under-represented minorities, who have used these skills to qualify successfully for academic positions once they leave Rutgers.

This award will be used to purchase a high-resolution inductively coupled plasma mass spectrometer with a Laser Ablation sample introduction unit and standard autosampler and introduction systems. This instrumentation is crucial to the research of members of the Departments of Marine and Coastal Sciences, Earth and Planetary Sciences and Environmental Sciences at Rutgers-New Brunswick, as well as users from associated departments at Rutgers-Newark and elsewhere. The new ICP-MS will allow analysis of minute concentrations of trace elements in samples such as seawater, ocean particles, the tiny shells of marine organisms, and glacial ice. The LA will add new capability to the laboratory, and will allow tiny regions of solid samples, such as deep-sea coral skeletons, to be analyzed by vaporizing the solid and injecting the resulting condensed gasses directly into the MS, without the need to dissolve the sample in an acid solution. The current projects of the Principle Investigators include investigation of trace metal dynamics in the Arctic and Antarctic polar oceans, associated with the large field programs GEOTRACES and the Palmer Long Term Ecological Research, the development of geochemical methods to reconstruct past ocean chemistry from trace element concentrations in fossil deep-sea corals and the shells of fossil micro-organisms called foraminifera, and paleoceanographic reconstructions through the International Ocean Discovery Program (IODP). The researchers have been at the forefront of these fields for more than twenty years, and this award allows them to continue to innovate in these research areas.

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.

This project will support the management and implementation of a 60-day research cruise to the Amundsen Sea sector of the Antarctic continental margin to collect samples for measurements of a broad suite of trace elements and isotopes (?TEIs?), as part of the U.S. GEOTRACES program. GEOTRACES is a global effort in the field of Chemical Oceanography, the goal of which is to understand the distributions of trace elements and their isotopes in the ocean. Determining the distributions of these elements and isotopes will increase the understanding of processes that shape their distributions and also the processes that depend on these elements. Key TEIs include essential micronutrients such as iron and zinc; ?tracers? such as aluminum, manganese, and isotopes of nitrogen, thorium and neodymium that can be used to investigate modern and ancient ocean processes; and elements such as lead that are indicative of human activities. In the Southern Ocean, the Antarctic continental margins are important as sources of micronutrient trace elements such as iron, which is required to support biological production and carbon export over the Antarctic shelf and in offshore waters of the Antarctic Circumpolar Current. Moreover, these regions are experiencing rapid environmental changes that are expected to impact oceanic circulation and biogeochemical cycles, for which TEIs provide crucial data needed to test and refine numerical models of the Earth system. The Amundsen Sea sector holds particular interest because of the pronounced, decadal-scale increases in the melting rates of glacial ice shelves that border the region, driven by intrusions of warm Circumpolar Deep Water onto the continental shelf. This melting has potentially major impacts on global sea level, on the formation of Antarctic Bottom Water in the Ross Sea, and on the regional ecosystem.

The cruise will comprise essential sampling operations (collection and shipboard processing) and ancillary measurements (hydrography, nutrients, algal pigments) in support of multiple, individual science projects, following the successful model of previous U.S. GEOTRACES cruises in the Atlantic, Pacific and Arctic ocean basins. The cruise will sample the ocean region between 100°W and 135°W, with stations ranging from 67°S in the Antarctic Circumpolar Current southward to the Amundsen Sea continental shelf, including stations adjacent to several rapidly melting ice shelves and in highly-productive shelf polynyas. Water column samples will be collected using conventional and trace-metal clean CTD-rosette systems, in-situ high-volume pumps, and a towed fish sampler or small boat, using established methods. Sampling time will also be provided for collection of sea ice, floating glacial ice, and seafloor sediments. To facilitate coordination with a complementary open-ocean cruise and ensure access to the study region to document the impact of biological processes, the cruise is planned for late austral summer (late January-late March). Beyond the disciplinary contributions, the proposed research will contribute knowledge concerning the cryosphere and its impacts on global sea level and ocean circulation, regional ecosystems and biological processes, ocean-atmosphere interactions, and past and future environmental change. The project will contribute to STEM education and outreach through the participation of an NSF-funded PolarTREC education professional, and a K-12 STEM program for students from underserved and underrepresented schools run by Rutgers University education specialists. To foster public engagement, the investigators will partner with the UCSC Science Communication Program to engage freelance science journalists to profile research in this spectacular and harsh Antarctic environment.

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.

The goal of the international GEOTRACES program is to understand the distributions of trace chemical elements and their isotopes in the oceans. This project will generate a dataset of 40 trace elements on suspended particles and surface sediment samples collected on the GEOTRACES GP17-ANT cruise to the Amundsen Sea, West Antarctica. The Amundsen Sea hosts the most productive polynya per unit area in all of Antarctica, with biological carbon uptake ten times higher than the average for the Southern Ocean. Over the past 30 years, this region has become a primary locus of increased freshwater input, as the fastest melting glaciers in West Antarctica deliver huge and increasing volumes of freshwater to the Amundsen Sea. The major contribution of this region to global sea level rise is well documented, but the impact of accelerated additions of meltwater and associated chemical constituents on the biogeochemistry of the Antarctic shelf waters, and in particular on the cycling of trace elements, has not received comprehensive investigation. Hypotheses addressing four key components of the biogeochemical system in the Amundsen Sea will be tested, and results will closely mesh with complementary efforts proposed by other GP17-ANT investigators. The project will support a graduate student and several undergraduate interns, with a focus on broadening participation in STEM. The investigators will also work with established programs to create meaningful out-of-school science experiences for middle and high school students.<br/><br/>The aim of the project is to quantify and interpret the distributions of particulate trace elements in approximately 500 samples covering a large swath of the Amundsen Sea shelf, including waters influenced by five major ice shelves, and in the adjacent iron-limited Southern Ocean waters bounded by 100°W and 135°W, and south of 67°S. The investigators will use size-fractionated sample collection, total acid digestion and weak acid leaching, and well-established mass spectrometric methods to determine concentrations and probe the physico-chemical state of the particulate trace elements. The team will use the new data to investigate the following issues: 1) the role of phytoplankton, with a focus on Phaeocystis and diatoms, dominant taxa on the Amundsen Sea shelf, in driving element cycling in the upper water column while experiencing variable degrees of iron stress; 2) the “meltwater pump” which generates vigorous and particle-rich outflow from ice shelf cavities; 3) the bottom nepheloid layer of resuspended sediments as a reaction zone that determines the composition of the sedimentary paleo-record and also modulates of chemical fluxes at the sediment-water boundary; and 4) the rare earth elements (REE), which the team proposes carry unique geochemical information about terrigenous particle provenance among the geologically diverse glacial drainage regions, and also includes a labile particulate fraction whose magnitude and inter-element ratios may serve as a relative index of element scavenging intensity that can be applied to predict regions of maximal scavenging for other particle-reactive elements.<br/><br/>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.