November 19, 2014: Our paper is now online as an accepted unedited version: Bone A, Matson CW, Colman BP, Yang X, Meyer JN, Di Giulio RT, 2014, “Silver Nanoparticle Toxicity to Atlantic Killifish (Fundulus Heteroclitus) and Caenorhabditis Elegans: A Comparison of Mesocosm, Microcosm and Conventional Laboratory Studies.” Environmental Toxicology and Chemistry, November, n/a – n/a. doi:10.1002/etc.2806.
November 11, 2014: Audrey Bone's paper (collaborator and PhD Student in Rich Di Giulio's lab) was just accepted at the SETAC journal, Environmental Toxicology and Chemistry, just in time for her to go to the SETAC annual meeting! This paper details the toxicity of silver nitrate and silver nanoparticles "aged" in several contexts including in our wetland mesocosms, in wetland mesocosm water in the lab, or in microcosms representative of the mesocosms. Toxicity is evaluated by using standard in-lab toxicity assays in one of my favorite fish (Fundulus heteroclitus, a.k.a. Atlantic killifish or mummichog) and everyone's favorite nematode (Caenorhabditis elegans). Take home messages: 1) toxicity of silver is changed by the transformation of silver in the environment, sometimes increasing and sometimes decreasing toxicity; 2) despite our efforts to replicate the mesocosms in microcosm form, our lab aging of particles has not replicated what we see in the field, likely due to the role of UV light; and finally, 3) without mesocosm experiments (capital and labor intensive but information rich), we would not have seen these important results. I'll post a link to the paper once it is online.
November 1, 2014: A huge (belated) welcome to the Bernhardt lab for Steve Anderson, my successor as lab-o-lympics champion in 2012. Steve was working in the Wright lab here at Duke, but we managed to recruit him in September to be the new technician on our work looking at the ecosystem impacts of nanomaterials. If you can't beat them, recruit them, and boy am I glad we did.
August 31, 2014: Finished taking down most recent wetland mesocosm experiment! See August 8th post for experiment details. It was two weeks of sampling water and soils, as well as catching fish, tadpoles, and a range of benthic macroinvertebrates. Many thanks to Leanne Baker (Matson and King labs, Baylor University) for her expertise, guidance, and assistance. Without her help it wouldn't have been possible. Thanks also to Chris Ward (Hunt lab, Duke Marine Lab) and Carley Gwin (Gunch Lab, Duke) for helping pick "bugs" (slang for benthic macroinvertebrates) even though their focus has been on other "bugs" (largely bacteria and archaea). And finally, thanks to Mengchi Ho and Wes Willis (Wetland Center, Duke), and Fabienne Schwabb (Wiesner lab, Duke) for their plant harvesting prowess.
August 29, 2014: The paper that I wrote with Stephanie Yelenik, Jonathan Levine, and Janneke Hille Ris Lambers, "A Mechanistic Study of Plant and Microbial Controls over R* for Nitrogen in an Annual Grassland," came out in PLOS ONE today!!! This paper used techniques form ecosystem ecology to examine mechanisms underlying the R* theory of competition in communities.
If ever a paper had coequal first authors, this is the one, and I am delighted that PLOS ONE denotes this with yin yang symbols! This paper emerged from Stephanie and I batting around ideas in the lab one day over coffee. With Janneke and Jonathan we came up with what seemed like a simple side project. We were wrong, but it may just be that there is no such thing as a simple side project if that side project results in a publication.
August 8, 2014: Nearly time to take down our current wetland mesocosm experiment. We've been looking at the classic ecological dichotomy of pulse vs. press (single one time addition or chronic addition of a substrate or stressor) as it pertains to silver nanoparticles, an emerging contaminant. Most lab studies use high concentration pulse exposures, but actual exposures in natural ecosystems to these contaminants are expected to be low concentration and chronic. I'll be giving a talk in a "Wetlands" session on a subset of the results from this experiment at ESA in Sacramento on Wednesday, August 13th at 9:20, one year to the day after the start of this experiment. Good timing, eh? Then I'll be hurrying back to begin our final harvest immediately following ESA.
July 2014: Manuscript examining the plant and microbial mechanisms underlying resource ratio theory (sensu Tillman's R* theory) has been accepted at PLOS One! This was work from my time at UCSB, and was a collaboration with Stephanie Yelenik, Janneke Hille Ris Lambers, and Jonathan Levine. It was a single growing season experiment that took ~6 years to get accepted (not for lack of trying). The paper links community ecology and ecosystem ecology. I think by linking the two, it has had a heck of a time getting through review. We've learned many lessons about the benefits and perils of interdisciplinary research in the process, and the review process has made it a better paper.
July 2014:Promoted from Postdoctoral Associate to Research Scientist! My day to day responsibilities will be fairly similar (research, mentor, write, repeat), but now I have the ability to be a PI on grant applications, and teach classes here at Duke. Since Emily is in Germany for a year on sabbatical, I'll be offering her Biogeochemistry class (BIO/ENV 572) in Spring 2015.
June 2014: Had to say goodbye this month to Anna Fedders, who has been an integral part of our current wetland mesocosm experiment examining the impacts of pulse vs. chronic nanoparticle pollution. Anna is off to graduate school at University of Illinois at Urbana-Champaign and is sorely missed already!
It's been a busy year so far. A lot has happened since December, but the most important milestone is the publication ("just accepted") of our wetland mesocosm paper in ES&T. In this paper, we describe the fate, transport, and impacts of Ag added to wetland mesocosms as either AgNO3, 12 nm or 49 nm silver nanoparticles. Many thanks to my coauthors, and to everyone who helped with the experiment!
Benjamin P. Colman
» Bernhardt Lab «
» Duke River Center «
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Research interests: Biogeochemistry, ecosystem ecology, plant microbe interactions, microbial ecology, ecotoxicology
Phone: (919) 660 - 7262
Email: benjamin.colman at duke.edu
Durham, NC 27708
124 Science Drive
Durham, NC 27708