News archive

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! 

April 2014: 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!

December 2013: 
Was invited to give a talk and sit on a panel on the first day of the recent NSF-EPA-USDA Nanoscale Science and Engineering Grantees Conference in Arlington, Virginia. Good talks on measuring nanomaterials in complex environments (e.g., CNTs in biological organisms, metal and metal oxide particles in environmental media), synthesizing nanomaterials, manufacturing nanomaterials and nano-enabled products, and doing so in as sustainable a fashion as possible.

November 2013: Paper published in ES&T detailing experiments that I helped design, coordinate, and in the case of duckweed, conduct. These experiments tested the toxicity of sulfidized silver nanoparticles (dominant fate in wastewater effluent and biosolids, as well as in anaerobic sediments) to a range of different organisms.

October 2013: Gave a nano-focused seminar for the UNCW Department of BIology and Marine Biology's seminar. Really enjoyed my visit and meetings with faculty and students, and ate some seminar snacks including delicious TiO2 nanoparticle-containing Oreos. Many thanks to Will White for hosting me, and everyone who made time to meet with me.

August 2013: Started new round of wetland mesocosm experiments as a part of CEINT funded research. This round we're looking at the impacts of a pulse exposure (like our last experiment) as compared to chronic exposure, and weathered Ag nanoparticles (Ag2S nanoparticles) as compared to fresh nanoparticles (Ag(0) nanoparticles).

July 2013: Final paper from dissertation research (Colman and Schimel, 2013, SB&B) highlighted by Elsevier as #16 out of the 25 most downloaded articles in Soil Science in 2013. 

June 2013: Was an invited speaker at the International Conference On the Biogeochemistry of Trace Elements (ICOBTE) for their special symposium on the Transport, Fate, Bioavailability and Effects of Manufactured Nanoparticles in the Terrestrial Environment.

May, 2013
Q&A in A to Z Nanotechnology detailing our experiment examining the effects of a realistic exposure of a terrestrial ecosystem to silver nanoparticles in biosolids. Warning, contains giant photos of my head.

May 14, 2013: Spoke at the Museum of Life + Science's Periodic Table Science Cafe at the Broad Street Cafe. Enjoyed great food, cool refreshing beverages, and an attentive audience brimming with stimulating questions.April 2013
Upside-down mesocosm cake, anyone? Emptied out our last round of 24 terrestrial mesocosms, and gearing up for ver. 2.0, now with 120 mesocosms run for two years.

March 30, 2013: For the fifth straight yearwe presented at Nanodays at the North Carolina Museum of Life + Science! Had tons of help from Anna Fedders, and Raven Bier of the Bernhardt lab.

March 2013" Gave invited seminar at the Cary Institute of Ecosystem Studies on, "Impacts of manufactured nanomaterials in terrestrial and aquatic ecosystems."

February 2013: "Low concentrations of silver nanoparticles in biosolids cause adverse ecosystem responses under realistic field Scenario" published in PLOS ONE.

January 2013:  "Drivers of microbial respiration and net N mineralization at the continental scale" published in Soil Biology and Biochemistry.

December 2012: Disappointing middle of the pack finish in the 2012 Lab-o-lympics, but won "Best Last Year" award for my previous gold medal finish, and did better than two of the three PIs.

September 2012: "Effects of Silver Nanoparticle Exposure on Germination and Early Growth of Eleven Wetland Plants" published in PLoS ONE.

June 2012: Paper published in ES&T detailing Part II of a microcosm study, focused on changes in silver nanoparticle toxicity to fish and daphnia in complex environments caused by the changes in the physicochemical characteristics of the system resulting from the particles (Bone, Colman, Gondikas, Newton, Harrold, Cory, Unrine, Klaine, Matson, Di Giulio).

May 2012: Paper published in Ecotoxicology detailing microbial impacts of a commercially available form of silver nanoparticles when added to sediments and streamwater (Colman, Wang, Auffan, Wiesner, and Bernhardt).

March 2012: Paper published in Environmental Science and Technology detailing Part I of a microcosm study, where we showed that nanoparticles added to complex aquatic systems (water, sediment, plants) change the physicochemical characteristics of the system dramatically, and that these changes feed back to modify nanoparticle behavior (Unrine, Colman, Bone, Gondikas, and Matson).