UMass Dartmouth SMAST Visit

Last week Neil Fredrick and I visited the School of Marine Science and Technology (SMAST) at U. Mass. Dartmouth. I gave a seminar and we had some very good discussions about science and research with SMAST faculty. One thing we were very excited about was meeting Dr. Changsheng Chen, who is the developer of the FVCOM model, which we are using for our Lake Taihu project. Dr. Chen gave us some useful advice on our model and also showed us his  Northeast Coastal Ocean Forecast System (NECOFS). I spent a couple of hours playing with this system today. For someone interested in surface water quality, its really interesting technology. I made the plot below, which shows the currents at 8am today, outgoing tide. A while back, Boston discharged its wastewater at Moon Island (red circle). Then, they constructed two treatment plants, at Nut Island (green circle) and Deer Island (yellow circle). Seems like a good (or better) choice considering the currents. Now Boston has just one treatment plant at Deer Island, but the outfall is 9 miles offshore. Here is the link to the system:
http://porpoise1.smast.umassd.edu:8080/fvcomwms/

New paper: Mechanisms of Heterogeneity in Phytoplankton

I am pleased to announce the publication of our paper “Use of Agent-Based Modeling To Explore the Mechanisms of Intracellular Phosphorus Heterogeneity in Cultured Phytoplankton“ by Neil Fredrick et al. in Applied & Environmental Microbiology. I want to use this post to highlight an important point that has real consequences for our biogeochemical models. This paper is related to a previous one where we looked at the nutrient content heterogeneity in a field population. One of the main conclusions from that research was that microscale patchiness leads to large heterogeneity. This process is related to zooplankton excretion and thus does not operate in laboratory experiments. This means the heterogeneity in laboratory experiments is much lower than in the field, and that, considering the effect of heterogeneity, means that parameters estimated from the lab are not applicable to the field. Specifically, the maximum growth rate in the Droop quota model should be reduced by a factor of about 0.7. Here is a side-by-side comparison of the laboratory and field results:

Here are links to the “lab” and “field” papers.
http://aem.asm.org/content/79/14/4359.short
http://link.springer.com/article/10.1007/s10452-011-9384-6
And if you want to try the model, here it is:
http://www.systemsbioecology.org/files/QuotaHeterogeneity/QuotaHeterogeneity.html

Lake Taihu Field Report

Earlier this month, PhD student Neil Fredrick and I were in China for a meeting on our Lake Taihu project. The picture below is me standing on the dock at the Taihu Laboratory for Lake Ecosystem Research (TLLER) during a bloom. Despite the rather challenging conditions (107dF & high humidity), the trip was enjoyable and very productive. Specifically, we connected with a hydrodynamic modeler (Li Wei) and started combining her hydrodynamic model with Neil’s N cycle model. This will allow us to predict spatial patterns in the N cycle processes.

Summer Research Wraps Up

This year, our summer research focused on understanding the role of N fixation on the N cycle and export of N from lakes. The team was led by PhD student Xiaodan Ruan and included PhD student Frank Schellenger, RET Bruce Brender and YSPs Garlyn Colas and Janice Tso. Janice and Garlyn made a very nice oral presentation at the wrap-up meeting on August 2. Here is a picture of the team.

Antibiotic Resistance Modeling Lecture NOW AVAILABLE

I published a lecture video entitled “Modeling antibiotic resistance in the ambient aquatic environment”. This 1-hour lecture is suitable as an advanced topic in graduate-level surface water quality modeling courses. The lecture provides an introduction to antibiotics, antibiotic resistance (AR) and AR in the ambient environment. It presents a mathematical model (MAQUIS) and application to tetracyclines in the Poudre River, as well as a hands-on tutorial and homework assignment. If you are teaching surface water quality modeling, you may find this lecture to be a valuable addition to your course. Please contact me if you have any questions or comments. Here is the link to the lecture: http://www.youtube.com/watch?v=RblyKjlPxds&feature=share&list=UU-l5JSjKdLI7fGaYx_l-i5Q

FEMS Conference Report

I am at the Congress of European Microbiologists (FEMS 2013) in Leipzig http://www2.kenes.com/fems2013/pages/home.aspx. I helped organize a session on modeling, and presented a poster on intraspecific internal nutrient heterogeneity and a talk on bet hedging in yeast. This is a very interesting meeting and I am learning a lot about microbiology. Let me tell you about one thing that stands out to me. You know, there is now a lot of realization on the role of the gut bacteria (microbiome) on human health. A couple of people presented research linking (pretty conclusively in my mind) the biodiversity in the gut to obesity and infection risk. Those are important and interesting problems, but I am not a medical person so my interests are more in the tools they are using. In one experiment they took germ-free mice and inoculated them with various bacteria. Wow! I wish we could do this with our environmental systems. I mean, can I have a few sterile Charles Rivers that I can inoculate with different bacteria? Please? Of course, we can make lab experiments, but those don’t include any of the complexities of the real system. Whole lake experiments can be and are done (e.g. at the Experimental Lake Area in Canada), but there we are limited to simple perturbations – we don’t have direct control of the microbe population. I think because of these types of experimental capabilities (and also availability of funding in the medical area), some of the most exciting advances in microbial ecology in the near future will come from the medical arena. Next stop: Shanghai and Lake Taihu.

Victory for the Charles!

This Saturday, the Charles River opened for swimming! For the first time in over 50 years we had public swimming. This event was organized by the Charles River Conservancy, who also led the effort to bring swimming back to the river over the past years. My research group has helped out by doing some water quality monitoring at potential (ahem actual!) swimming sites. Of course I had to participate. And you know what? It was wonderfully refreshing! And surprisingly so! I didn’t even realize and I wonder if all those people on the Esplanade realize that there is a cool and refreshing (and swimmable) river just a few feet from where we sweat in the sun. The plan is to do more of this, and I think this would significantly improve the quality of life in Boston!

See the article on the NU news blog here:http://www.northeastern.edu/news/2013/07/love-that-clean-water/

Read the article in the Boston Globe here:http://www.boston.com/metrodesk/2013/07/13/charles-river-opens-for-public-swim-for-first-time-since/4tgCdQ1cONXeN6SPvhe6rI/story.html

Visit the swimming page at the Charles River Conservancy here:http://www.thecharles.org/projects-and-programs/swimmable-charles/