William Landing

Research

1. National Science Foundation (Chemical Oceanography OCE-0752351). Collaborative Research: Participation in the GEOTRACES Intercalibration Cruise.

The GEOSECS program of the 1970s and the present-day CLIVAR Repeat Hydrography program investigation of trace elements and their isotopes (TEI) acknowledge TEIs not only as nutrients or contaminants, but also as powerful tracers or proxies of oceanographic processes. The basin-wide sections of dissolved and particulate trace elements and total and soluble aerosol trace elements of the CLIVAR Repeat Hydrography program have lead to a better understanding of how global ocean biogeochemical cycles operate. The dissolved Fe and Al data will be used to improve and constrain coupled ocean/atmosphere nutrient and carbon cycling models, and permit more accurate prediction of the role played by atmospheric Fe deposition across various biogeographic zones of the world's major ocean basins. The Landing/Measures sampling and sub-sampling systems are being adopted by scientists from several countries and the GEOTRACES program as a model for collecting uncontaminated trace element samples that are consistent with international global scale hydrographic programs. In this context the new international program GEOTRACES is proposing a series of enabling activities to ensure the accuracy and precision of analytical methodology before sampling transects across ocean basins are started. An important part of this activity is to ensure that the newly constructed GEOTRACES rosette system can obtain seawater samples that are free of trace element contamination. This proposal seeks funding to participate in the GEOTRACES Intercalibration program and to provide access to the established reliability of the Landing/Measures sampling and sub-sampling systems for intercalibration with GEOTRACES sampling and sub-sampling systems. This research will be a collaborative effort among two PIs and a Post-Doctoral Researcher over 2 years. The goals of our participation in the GEOTRACES Intercalibration program are first, assist in the evaluation and development GEOTRACES sample acquisition, handling, and storage protocols during the initial Intercalibration Cruises with the a trace metal-clean rosette system of 12L GO-Flo bottles deployed on Kevlar conducting line and sub-sampled in a clean lab (Landing and Measures system used on CLIVAR cruises). Second, our goal is to perform shipboard flow injection analysis and intercalibration of dissolved Al and Fe, core GEOTRACES TEIs. Finally, our goal is validate the determination of iron in seawater by high-resolution isotope dilution inductively coupled plasma mass spectrometry after Mg(OH)2 coprecipitation at the University of Hawai'i.

 
 
2. National Science Foundation (Chemical Oceanography OCE-0752832). "GEOTRACES: Intercalibration for Aerosol Sampling and Analysis."

Project Summary: The international GEOTRACES program is proposing a series of enabling activities to ensure the accuracy and precision of analytical methodology before sampling transects across ocean basins are started. The importance of measuring trace element and isotope (TEI) concentrations and deposition to the oceans for aerosols and rainfall is described in the GEOTRACES Science Plan (2006). NSF funding for US scientists involved in GEOTRACES over the next two years will be devoted to a series of intercalibration experiments to establish protocols for sample collection and analysis. These protocols will be developed in collaboration with international scientists so that the GEOTRACES research cruises will yield a data set that is accurate, precise and internally-consistent. This proposal is to acquire, test, and intercalibrate equipment and methods for the collection of aerosols and rainwater on the GEOTRACES cruises to be conducted over the next decade or so. The rationale for collecting and chemically-characterizing such samples is discussed below. Because GEOTRACES is in the "intercalibration" phase, this project does not intend to fulfill the specific GEOTRACES research objectives regarding atmospheric input, other than to establish the sample collection and analytical protocols that will enable us to meet those objectives. We propose to:

  1. Acquire high-volume sampling equipment to be made available for deployment on GEOTRACES research cruises for the collection of total aerosols (TSP)and size-fractionated aerosols on low-blank filter matrices that can be subsampled and shared with colleagues around the world.
  2. Acquire automated rainwater sampling equipment to be made available for deployment on GEOTRACES research cruises for the collection of large volumes of unfiltered and filtered rainfall that can be subsampled and shared.
  3. Test and intercalibrate the equipment during two field experiments (2008 on the RSMAS-University of Miami roof and 2009 on the Tudor Hill Marine-Atmospheric Observatory Sampling Tower in Bermuda).
  4. Invite collaborators from the US and elsewhere to participate in sampler intercalibration during the field experiments.
  5. Distribute aerosol and rainwater subsamples to collaborators from the US and elsewhere for the purposes of intercalibrating analytical methods.
  6. Collect intercalibration data from the various collaborators and produce an intercalibration document (for journal publication).
  7. Prepare "handbooks" describing the atmospheric sampling and analytical protocols for use on GEOTRACES cruises; to be shared with our US and international GEOTRACES colleagues.

 
 
3. National Science Foundation (Chemical Oceanography OCE-0649639). "Collaborative Research: Global Ocean Survey of Dissolved and Particulate Iron and Aluminum and Aerosol Iron and Aluminum Solubility Supporting the CLIVAR Repeat Hydrography Project (2007-2009)."

Project Summary: The Trace Metals component of the CLIVAR Repeat Hydrography program has provided an unprecedented opportunity for quantifying the distributions of total and soluble aerosol Fe and Al and for measuring water column profiles of dissolved and particulate Fe and Al across entire ocean basins. The one-degree profile spacing has revealed fine-scale features in the distributions of dissolved and particulate Fe and Al that were previously unrecognized. Coupling aerosol and water column sampling has shown how dust input can influence the upper ocean chemistry of Fe and Al. Our initial funding (to Bill Landing, Chris Measures, and Joe Resing) was used to participate in 4 cruises (A16N, Iceland to Brazil in 2003; P02, Japan to San Diego in 2004; P16S, Tahiti to New Zealand in 2005; and P16N, Tahiti to Kodiak in 2006). The water column sampling equipment and seawater filtration procedures were recently tested on the "Sampling and Analysis of Fe" (SAFe) cruise (October 2004) and shown to provide uncontaminated samples for dissolved Fe, Ni, Cu, Zn, Cd, and Pb. Our data demonstrate that it is feasible to "scale up" the traditional (and time consuming) GoFlo/Kevlar hydrocast sampling technique: we can collect a 12 depth profile to 1000 meters in under 60 minutes. In addition, FSU graduate student Paul Hansard participated in the P02 and P16N cruises to measure dissolved Fe(II) on the water column profiles using a highly sensitive modification of the FeLume chemiluminescent Fe(II) technique. Some of these results will be discussed in the body of this proposal. So far, we have collected 185 daily integrated sets of replicate aerosol samples, 3,114 0.4 µm filtered seawater subsamples, and 2,488 unfiltered seawater samples from the 4 cruises. Hundreds of additional subsamples have been collected for Mark Altabet, Amy Apprill, Jim Bishop, Ed Boyle, Ken Bruland, Gary Klinkhammer, Dave Krabbenhoft, Dave Nelson, Karen Selph, and Alan Shiller. Data from these cruises has been presented at various AGU, Ocean Sciences, and GEOTRACES meetings, and is now being processed and submitted for publication.

We propose to participate in three more CLIVAR cruises in 2007 (I9N and I9S; Indian Ocean), 2008 (I6S), and 2009 (I7N). We are responsible for measuring: dissolved Fe and Al (shipboard flow-injection analysis); total suspended matter Fe and Al (EDXRF); total aerosol Fe and Al (EDXRF); soluble aerosol Fe and Al (ICPMS), and soluble aerosol Fe(II) (shipboard chemiluminescence). We have added more components to our sampling and analysis. In 2003, we borrowed a MOUDI cascade impactor to measure total aerosol Fe and Al and their solubility as a function of particle size on the A16N cruise. We then purchased a 4-stage MOUDI impactor (3.2, 1.0, 0.56, and 0.056 µm size cutoffs) for the P02, P16S, and P16N cruises. We measure aerosol Fe and Al solubility in both surface seawater and ultrapure DI water. The DI water aerosol leach solutions will be analyzed for additional elements by high-resolution magnetic sector ICPMS (Li, Na, Mg, Al, Si, P, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Nb, Cd, Sb, Cs, La (and REE), Pb, Bi, Th, and U. We will digest and analyze the total aerosol filters for these same elements, yielding a data set for the aerosol solubility of many elements including potentially bio-limiting elements such as Mn, Co, and Zn. We developed an isotope dilution technique for measuring dissolved Fe, Ni, Cu, Zn, Cd, and Pb on 12 mL samples. NSF funding for the retrospective analysis of the seawater samples from the A16N, P02, P16S, and P16N sections was granted to Landing in 2006.

 
 
4. National Science Foundation (Chemical Oceanography OCE-0550317). "Trace Element Analysis of Aerosol and Seawater Samples Collected on the A16N, P02, and P16S CLIVAR Cruises."

Project Summary: The Trace Metals component of the CLIVAR Repeat Hydrography program has provided an unprecedented opportunity for quantifying the distributions of total and soluble aerosol Fe and Al and for measuring water column profiles of dissolved and particulate Fe and Al across entire ocean basins. The one-degree profile spacing has revealed fine-scale features in the distributions of dissolved and particulate Fe and Al that were previously unrecognized. Coupling aerosol and water column sampling has shown how dust input can influence the upper ocean chemistry of Fe and Al. The initial funding (to Landing, Measures, and Resing) was used to participate in 3 cruises (A16N, Iceland to Brazil in 2003; P02, Japan to San Diego in 2004; P16S, Tahiti to New Zealand in 2005). We collected 137 daily integrated sets of replicate aerosol samples, 2,658 0.4 ?m filtered seawater subsamples, and 2,336 unfiltered seawater samples from the 3 cruises. The water column sampling equipment and seawater filtration procedures were recently tested on the "Sampling and Analysis of Fe" (SAFe) cruise (October 2004) and shown to provide uncontaminated samples for dissolved Fe, Ni, Cu, Zn, Cd, and Pb. Our data demonstrate that it is feasible to "scale up" the traditional (and time consuming) GoFlo/Kevlar hydrocast sampling technique: we can collect a 12 depth profile to 1000 meters in under 60 minutes. The FSU portion of the initial budget ($218,378 in direct costs over 3 years) covered our participation in the cruises, analysis of seawater-soluble and DI water soluble aerosol Fe, Fe(II), and Al, and analysis of 20% of the seawater subsamples for Fe using isotope dilution HR-ICP-MS. In addition, FSU graduate student Paul Hansard participated in the P02 cruise to measure dissolved Fe(II) on the water column profiles using a highly sensitive modification of the FeLume chemiluminescent Fe(II) technique. Some of these results will be discussed in the body of this proposal.

Given the broad interest in developing geochemical tracers of oceanographic processes (e.g. GEOTRACES), it is very cost effective to use existing samples to explore these possibilities. Our aerosol and water column samples from the 3 CLIVAR cruises are unique in this regard. This proposal requests funds to analyze the aerosol samples, the aerosol leach solutions, and the seawater samples from the first three CLIVAR cruises for additional trace elements. Aerosol samples will be digested and analyzed for at least 42 trace elements using HR-ICP-MS (trace metals, metalloids, REE). DI water aerosol leach solutions will be analyzed for these same elements plus Si (volatile SiF6 is lost during the HF digestion). Water column samples (and the seawater aerosol leach solutions) will be analyzed for Fe, Ni, Cu, Zn, Cd, and Pb using a newly-developed method for multi-element isotope dilution HR-ICP-MS after extraction and elution using a small 8-hydroxyquinoline column. The data will be made available to the community to develop and constrain global ocean models of trace element, nutrient, and carbon biogeochemical cycling. We have also learned that the P16N CLIVAR cruise is scheduled for February-May, 2006. This would complete our N-S section across the Pacific.

Regarding the intellectual merit and broader impacts of the research, the basin-wide sections of dissolved trace elements and total and soluble aerosol trace elements will lead to better understand of how global ocean biogeochemical cycles operate. The Fe data feed directly into coupled ocean/atmosphere nutrient and carbon cycling models, and permit more accurate prediction of the role played by atmospheric Fe deposition across various biogeographic zones of the world's major ocean basins.

 
 
5. Electric Power Research Institute, "Collection and analysis of atmospheric deposition of mercury and trace metals to the Pensacola Bay watershed." Project Summary: Atmospheric concentrations of mercury (Hg), nitrogen and other contaminants have increased since the industrial revolution. Hg emissions to the atmosphere are primarily associated with coal burning power plants and waste incinerators (Dvonch et al.1998). Deposition of atmospheric constituents to land and water surfaces occurs at a wide range of scales, from less than a kilometer to hundreds of kilometers from the emission sources. Thus, airsheds can encompass huge and often amorphous (depending on climate conditions) areas, usually 10 to 100 times greater than watershed area (Valigura et al. 2001).

Air quality in Pensacola Bay is affected by emissions from industrial sources, automobiles and other vehicles as well as other stationary area sources (FDEP 1998). Industrial sources include a coal fired electric generating plant, a paper mill, chemical and other manufacturing companies (EPA website: http://www.epa.gov/air/data/reports.html). Major sources of Hg emissions in 2002 came from the electric generating plant and paper mill. Medical incineration is still occurring in this region at Sacred Heart Hospital although estimated emissions in 2003 were 0.012 lbs. Industrial operations in Escambia and Santa Rosa counties also emit arsenic, cadmium, chromium, lead, nickel and selenium. Industrial activities such as pulp and paper production and industrial heat production are the major sources of most of these trace metals.

Prior monitoring and analysis: Monitoring of atmospheric deposition of mercury, trace metals and major ions in the Pensacola Bay watershed was initiated with funding by the Environmental Protection Agency in 2004 and completed in December 2007. This project addressed the question, what is the atmospheric deposition of mercury and trace metals such as arsenic, cadmium, chromium, lead, selenium, iron and aluminum and major ions to the lower Pensacola Bay Watershed.