Trace Metal Biogeochemistry Laboratory

Welcome to the Twining Laboratory! We conduct interdisciplinary research on the biogeochemistry of metals in marine and aquatic systems. Our research is focused on the interactions between trace metals and aquatic organisms that have biogeochemical, ecological, or toxicological implications. Our work takes many forms and includes laboratory investigations with cultured phytoplankton and protists, as well as fieldwork to collect and study planktonic organisms in natural systems. Our work can be organized into a few themes:

Elemental composition of plankton

Planktonic organisms influence the distribution and geochemical fate of many important elements (including carbon) in the ocean by accumulating these elements into their cells. We strive to understand the factors that affect element stoichiometries in marine protists. Plankton also form the base of most aquatic food webs, and contaminants such as cadmium, selenium, silver, and mercury can become concentrated in plankton and passed to higher organisms. We are interested in the determining the occurrence and understanding the implications of metal accumulation in marine organisms.

Elemental composition of macroalgae

There is growing interest in commercial harvesting and aquaculture of seaweeds for use as human food and feed supplement for livestock. We are involved in several projects to understand the elemental composition of seaweeds. This work involves measuring arsenic (including inorganic and organic species), iodine, and major ions such as magnesium, calcium, and potassium, in addition to our favorite trace elements.

Micronutrient limitation and cycling

Phytoplankton growth in several large ocean regions is limited by the availability of iron and potentially cobalt, manganese, and even zinc. Some of our work is specifically focused on understanding trace metal cycling and biogeochemistry. We have been involved in projects investigating metal limitation and cycling in the equatorial Pacific Ocean, Indian Ocean, Southern Ocean, Arctic Ocean, Weddell Sea, Sargasso Sea, and in coastal waters off New Zealand, California, and British Columbia. We find that shipboard incubations help to keep our backs strong! We often use radioisotope tracers to study iron cycling, as well as chemiluminescence and electrochemical techniques to determine the redox speciation and complexation of trace metals.

Twining group members

We have been lucky to have many talented folks spend time working in our group over the years:

Past members

• Kristin Rouse – University of South Carolina undergraduate student
• Elyse Walker – University of South Carolina undergraduate student
• Kaitlin Duffey – University of South Carolina undergraduate student
• Allison Dalbec – University of South Carolina masters student
• Brandon Bozard – University of South Carolina masters student
• Daliangelis Nunez-Milland – University of South Carolina masters student
• Hai Lin – University of South Carolina PhD student
• Hannah McDaniel – Bigelow Laboratory REU intern
• Maria Nielsdottir – visiting postdoctoral researcher
• Meaghan Daley – Bigelow Laboratory REU intern
• Brittney Honisch – Bigelow Laboratory REU intern
• Conor Maginn – Bates College undergraduate intern
• Angel Ruacho – Bigelow Laboratory REU intern
• Jochen Nuester – Bigelow Laboratory postdoctoral researcher
• Kaitlyn Pritchard – Bigelow Laboratory REU intern
• Alice Chapman – Bigelow Laboratory REU intern
• Jeremy Jacquot – Bigelow Laboratory postdoctoral researcher
• Jade Enright – Bigelow Laboratory REU intern
• Brooke Stemple – Bigelow Laboratory REU intern
• Sarabeth George – Bigelow Laboratory REU intern and Sea Change Semester intern
• Dan Ohnemus – Bigelow Laboratory postdoctoral researcher
• Renee Torrie – Bigelow Laboratory REU intern
• Liz Mann – Bigelow Laboratory postdoctoral researcher
• Erika Alvarado – Bigelow Laboratory REU intern
• Gabriela Kim – Bigelow Laboratory REU intern and Sea Change Semester intern
• Dylan Halbeisen – Bigelow Laboratory REU intern

Current members

• Sara Rauschenberg – Senior Research Associate
• Laura Sofen – Bigelow Laboratory postdoctoral researcher