The biogeochemistry of marine particulate trace metals

• Main Author: Ohnemus, Daniel C.
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution 2014
• Subjects: Biogeochemical cycles; Marine chemical ecology; Melville (Ship) Cruise MV1101; Knorr (Ship : 1970-) Cruise KN199; Knorr (Ship : 1970-) Cruise KN204; Roger Revelle (Ship) Cruise RR1202; North Atlantic
• Online Access: https://hdl.handle.net/1912/6353

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2014 Marine particles include living and non-living solid components of seawater, representing a dynamic and chemically diverse mixture of phases. Through a combination of method development, basin-scale particulate collection and analyses, modeling, and field experiments, this thesis examines both the distributions of marine particulate trace metals and the underlying processes—inputs, scavenging, vertical and horizontal transport, and biotic uptake—in which marine particles participate. I first present the results of an intercalibration exercise among several US laboratories. We use inter-lab and intra-lab total elemental recoveries of these particles to determine our state of our intercalibration and to identify means of future improvement. We present a new chemical method for dissolution of polyethersulfone filters and compare it to other total particle digestion procedures. I then present the marine particulate distributions of the lithogenic elements Al, Fe, and Ti in the North Atlantic GEOTRACES section. A one-dimensional multi-box model that describes lithogenic particle distributions is also proposed and its parameter sensitivities and potential implications are discussed. I conclude with presentation of results from a series of bottle incubations in iron-limited waters using isotopically labeled Fe-minerals. We demonstrate solubilization of minerals ferrihydrite and fayalite via transfer of isotopic label into suspended particles. Funding was provided by the Williams College Tyng Fellowship, the MIT/WHOI Academic Programs Office, the International and US GEOTRACES Offices, and U.S. National Science Foundation (NSF) #0960880 and #0963026 and PLR #0838921 to P.J. Lam.