Thursday, September 19, 2013

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:

Monday, September 2, 2013

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.
And if you want to try the model, here it is: