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Examining controls on the solubility of iron and copper in Gulf of Alaska waters

Biological productivity in the Gulf of Alaska is limited by availability of the micronutrient iron. Copper, at high concentrations, can be toxic to marine organisms. The solubility of each element in seawater drives the biological response. This internship would carry out studies on seawater, dust, ash and sediment samples, to examine controls on the solubility in seawater of these elements.

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Project Hypothesis or Objectives:

Inputs of dust, volcanic ash, and sediments are suggested to be important sources of the trace element iron to the ocean, including in the Gulf of Alaska where biological productivity is limited by availability of iron. Atmospheric sources and sediments can both supply copper, which is known to be toxic to a variety of marine organisms.  However, controls on the solubility of both iron and copper are poorly understood, and are modulated by a variety of processes, including the presence of various organic ligands. This project offers the opportunity to examine the controls of iron and/or copper solubility in Gulf of Alaskan waters.   This work could include dissolution experiments carried out in fresh water spanning a range of pH values, intended to mimic conditions in clouds and in precipitation, or experiments in seawater, both with and without a variety of naturally occurring organic ligands that are thought to complex iron and copper in solution and enhance  solubility.  It could also involve measurements of copper and ligand concentrations in existing seawater samples.  This work could involve collaboration with Dr. Randie Bundy in the UW School of Oceanography.

Duration: Up to 12 months

Internship Location: Seattle, WA

Field(s) of Study: Chemistry, Geoscience

Applicable NSF Division: EAR  Earth Sciences, OCE  Ocean Sciences

Intern Type Preference: Either Type of Intern

Keywords: Nutrient, iron, productivity, ligand, glacier, copper, toxicity 

Expected Outcome:

The project will provide a valuable research experience to the intern and exposure to a project that examines the sources and behavior of iron and other trace elements to the coastal Gulf of Alaska region from dust, from coastal sediments, and from industrial emissions (through the Coastal and Marine Geology Program). The USGS has a large number of scientists close to retirement age, and the organization will  benefit from continual contact with upcoming PhD students who might be future USGS scientists or future collaborators of USGS scientists.

Special skills/training Required:

The intern should be capable of carrying out geochemical and/or biological experiments.  Ideally, s/he would have experience with trace-metal-clean sampling and experimentation, but this is not a necessity, as this could be taught.  The laboratory and instrumentation needed to carry out the work is available in Seattle.

Duties/Responsibilities:

The intern will carry out experiments either in the laboratory, or at sea, to examine the controls on the solubility of iron and/or copper.  The intern could also analyze the samples by inductively coupled plasma mass spectrometry (ICP-MS). The intern will have access to a variety of dust, sediment and seawater samples in the possession of John Crusius (USGS Alaska Science Center, affiliated with and located at the UW School of Oceanography, Seattle. The intern will have access to needed background information on each of these samples, including their collection location, date and/or depth, as well as some background geochemical information.