Browsing by Author "Fitzsimmons, Jessica"

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Collaborative Research: U.S. GEOTRACES PMT: Dissolved Trace Metal Distributions and Size Partitioning
Oceanography; TAMU; https://hdl.handle.net/20.500.14641/365; National Science Foundation
The goal of the international GEOTRACES program is to understand the distributions of trace chemical elements and their isotopes in the oceans. Many trace metals, which are by definition present in very low amounts, are essential for life and thus considered nutrients for phytoplankton growth. Other elements can be useful for tracing other ocean processes, and some (such as lead) are important because they are pollutants. The primary goal of this project is to measure the concentrations of iron, manganese, zinc, copper, cadmium, nickel, lead, and scandium dissolved in seawater along a line of full-depth ocean stations extending south from Alaska to Tahiti in the Pacific Ocean. Specialized sampling and filtration techniques will also enable these investigators and their colleagues to determine the distribution of these metals on very small particles. A graduate student and several undergraduate students will take part in the project. The U.S. GEOTRACES Pacific Meridional Transect, planned for the fall of 2018, aims to systematically and thoroughly determine the distribution of trace elements and isotopes on a cruise transect that spans zonal bands of sedimentary, atmospheric, and hydrothermal metal supplies; intersects several zonal biological production and oxygenation regimes; traverses the complex equatorial upwelling system; and encompasses the oldest known deep waters in the ocean. The primary goal of this proposal is to determine the concentrations of dissolved (<0.2 micron-filtered) micronutrient metals Fe, Mn, Zn, Cu, Cd, and Ni, as well as tracers Pb and Sc, on every water column and surface sample collected, using two well-established multi-element analytical methods that will be intercalibrated internally to maximize data quality. Many of these are "key elements" required for analysis on GEOTRACES cruises. Ultrafiltration will also be completed on all samples to determine the "truly soluble" (<0.003 micron) concentrations of these elements and to calculate, by difference, the colloidal (0.003-0.2 micron) fraction. The overarching goal of the proposed research is to understand the ocean fluxes and processes that control the distributions of micronutrient trace metals, which themselves modulate primary production and oceanic carbon dioxide uptake, in the Pacific Ocean. The proposed research will allow for an estimate of the meridional influence of each of these metal source fluxes and processes in the Pacific, which is poorly constrained to date due to the mostly zonal Pacific cruise transects in the past. Colloidal distributions are specifically targeted in order to derive additional information on the reactivity (with respect to both scavenging and bioavailability) of distinct dissolved metal pools, as well as to provide a basic constraint on metal physicochemical speciation, which is poorly defined for many of the eight metals.
GEOTRACES Arctic section: Dissolved micronutrient trace metal distributions and size partitioning-partitioning (Fe, Mn, Zn, Cu, Cd, and Ni)
Oceanography; TAMU; https://hdl.handle.net/20.500.14641/365; National Science Foundation
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.
REU Site: Observing the Ocean
Oceanography; https://hdl.handle.net/20.500.14641/1072; National Science Foundation
Texas A&M University's Department of Oceanography in College Station TX will host a Research Experience for Undergraduates (REU) Site program from 2019-2021. The program will focus on "Observing the Ocean" and will bring ten undergraduates to TAMU for a 10-week internship each summer. Mentors will be selected from the Departments of Oceanography, Geography and Civil Engineering and the Geochemical and Environmental Research Group (GERG), and students will have access to a variety of ocean observing instrumentation and data. They will participate in a cruise aboard the R/V Pelican to collect samples and data from the nearshore and offshore environments. Seminars and training modules will focus on data analysis, graphical representation of oceanographic data, data management, science writing and professional development. Students will present at weekly REU seminars and at the final REU Student Research Symposium, and they will complete a research proposal and either a final poster or written report. Student recruitment will focus on rising Sophomores and Juniors. The TAMU REU Site will provide a total of thirty undergraduates with internships over the three-year period. The program conducts a national search for applicants and seeks to engage students who are from schools with limited research opportunities. Most of the funding provided supports student stipends, housing and travel to attend the program. The focus of potential research projects for REU students at TAMU includes ocean observing technologies and analytical skills used to understand ocean issues such as hypoxia, early warning of harmful algal blooms, effects of oil spills and other pollutants, climate-induced variability in hydrography, and effects of ocean acidification. This project supports national goals of developing the next generation of scientists and the scientific workforce.