Microbe Ecology and Water Engineering (MEWE) Workshop Report

I am at DTW on my way back from MEWE in Ann Arbor, which was a very interesting meeting. http://www.mewe2013.org/ There are many areas where people study microbial ecology, including the ocean and the human gut, but also wastewater treatment plants (the “gut of the city”, Tong Zhang). It is interesting to see so many of the same problems (e.g. diversity) and tools (e.g. metagenomics) applied to these different environments. I participated in a session on antibiotic resistance and presented some of my modeling work on the Poudre River (see my post of June 16, 2013) and adaptation to the cost of resistance (see post of November 15, 2012). In this session, there were many very interesting data sets presented from treatment plants and ambient (“receiving”) water systems. Unfortunately they were all from different locations, which limits their utility for modeling. When I was developing my model I was able to take advantage of the large and comprehensive database developed for the Poudre River, and I think we need more of these concerted efforts - testbeds. It brings to mind a recent effort of the environmental engineering community to establish a network of testbed systems across the US (known initially as CLEANER, then WATERS). This effort did not succeed, maybe because it was too big, but it would have been really useful for developing models. Maybe a smaller-scale effort, focused on pharmaceuticals and personal care products (PPCPs) and antibiotic resistance, in one watershed could happen, and it should be pursued! Next stop: FEMS in Leipzig.

Edinburgh Workshop Report

Earlier this week I was in Edinburgh for a workshop on microbe modeling. The meeting focused on biofilms and included many presentations of experimental and modeling research. My work is not directly focused on biofilms per se, but there are a lot of the same tools/methods/questions/problems, so I found it very useful. I felt like I got a good overview of where the state-of-the-science is in this area. There is an interesting story about the use of modeling in biofilm science, which I want to briefly outline. It has to do with social conflict in biofilms. Specifically, bacteria in biofilms produce a sort of glue (extracellular polymer substance, EPS), which helps to hold the biofilm together. This is believed to be a public good (i.e. it benefits all cells in the biofilm), but the production is carried out by individual cells. This raises the question why individual cells produce this substance. In other words, why do they not evolve to not produce EPS and grow faster, while taking advantage of the EPS produced by other cells (i.e. why do “cheaters” not evolve). A few years ago, Xavier and Foster (PNAS, 2007) explored this question using a model. They found that, EPS is not a public good, but that it helps the cells that produce it to push up into the high oxygen regions. Subsequently, there have been a number of experimental investigations that have explored this hypothesis, and indeed, confirmed it. For more information see the workshop outline below. I think its an interesting story which illustrates the role of models in moving science forward, at a time scale greater than an individual paper or project. http://www2.ph.ed.ac.uk/~rallen2/epsrcworkshop.html

Antibiotic Resistance in the Aquatic Environment Trilogy & Off to Edinburgh

Hi Everyone:

I am pleased to announce the publication of our latest paper on modeling antibiotic resistance in the ambient aquatic environment. I want to use this post to try to put this paper into a larger context. You see, mathematical models are useful tools for managing and understanding environmental systems, and they have an established track record in environmental engineering and science. Water quality models can be used to relate discharges to ambient conditions, interpret field observations and test hypotheses. The first water quality model focused on the depletion of dissolved oxygen downstream of a wastewater discharge (Streeter-Phelps model).  Since then, models have continuously evolved to address changing societal needs, including pathogens (e.g. E. coli), eutrophication, toxics (e.g. PCBs), heavy metals and harmful algae (e.g. cyanobacteria). Antibiotic resistance in the aquatic environment is an emerging concern, and it makes sense for us to develop mathematical water quality models for this problem as well.

We are currently developing a model for this problem, and this latest paper includes the mechanism of co-selection by metals. Here are some results from the final model. The figure shows the Poudre River study area with WWTP inputs and urban land use.  The stream segments are shaded based on simulated tetracycline antibiotic resistance for the zinc co-selection case (Model H3\Zn, see paper). The data are from Pei et al. 2006.

Here are the links to the three papers, the newest one is listed last:

http://www.mdpi.com/1660-4601/8/2/480
http://iris.lib.neu.edu/aes/vol5/iss1/8/
http://ascelibrary.org/doi/abs/10.1061/(ASCE)EE.1943-7870.0000696

Next I am off to Edinburgh, Scotland to participate in a modeling workshop.

Guid cheerio the nou! (Good bye in Scots),
Ferdi


















 

Columbia & CDM Smith visits done, many coming up

Hi Everyone:

Just a brief note today. Last month I was at Columbia U for a seminar visit. It was nice to see some old friends, including my PhD advisor Manu Lall. Earlier this month a group of faculty from Northeastern went over to CDM Smith (http://cdmsmith.com/) to learn about each others work and explore possibilities for collaborations. Its always good to get a reality check of what the “real” problems are faced by practicing engineers and scientists.

Now (Tuesday) I am off to Turkey, where I will be for a month on a mix of personal and business things. I will give a research seminar at Middle East Technical University [Orta Doğu Teknik Universitesi (ODTÜ) in Turkish], the top technical university in Turkey. After that I have quite a busy summer, including a workshop in Edinburgh, a meeting in Ann Arbor, the FEMS conference in Leipzig, and then to China for project meetings and an IWA conference. Here are some links for these:
http://www2.ph.ed.ac.uk/~rallen2/epsrcworkshop.html
http://www.mewe2013.org/
http://www2.kenes.com/fems2013/pages/home.aspx
http://dipcon.rcees.ac.cn/

Maybe we will meet in one of these places!

Güle Güle ("bye bye" in Turkish)
Ferdi

Capstone Final Presentations & Columbia Seminar & Freeman Lecture

Hi again,

It’s that time of year again... Capstones! Please join us for the 2013 Environmental Capstone student presentations. This year, the course is focusing on nonpoint source phosphorus inputs to the Charles River - one of the most important contemporary problems in the Boston area (and worldwide). Four Capstone teams have been working with communities (Boston, Brookline, Cambridge and Newton) and professional mentors (from CDM Smith, Kleinfelder, CRWA and MWH) to design site-specific, tailored solutions. Please join us and learn about the solutions they came up with. A flyer with more details is posted here: https://www.dropbox.com/s/jr1l77tusfp8thg/EnvCapstone2013.pdf

On April 26 I will be at Columbia University for a seminar visit. If you are in the area and interested in learning more about my work, please come. Here is the advertisement:
https://www.dropbox.com/s/u4ppxc9t0uvv9w4/Hellweger%204-26.pdf

Finally, I would like to invite you to the 2013 Freeman Lecture, which this year focuses on hurricane barrier design (motived by Hurricane Sandy). The details are below.

Best regards,
Ferdi


2013 John R. Freeman Lecture
Hurricane Storm Barrier Design and Operation

Presenters:

Lawrence J. Murphy, P.E.
CDM Smith/New York, NY

Michael Bachand, P.E.
USACE

Around the world numerous hurricane or storm surge barriers have been
constructed to protect areas deemed to be critical. With the recent impacts to the
Northeast United States from Hurricane Sandy and to a lesser extent Hurricane Irene
which made landfall a year earlier, concepts for providing flood protection to storm
prone areas have been a national focus. This lecture will present a concept design of
a barrier to protect a portion of Lower Manhattan, as well as provide information on
the operation of two storm barriers that currently exist in the northeast. Various
types of barricades utilized around the world and their effectiveness will also be
presented.

DATE: Thursday, April 18th, 2013
TIME: Reception: 6 p.m./ Lecture: 7 p.m.
LOCATION: MIT’s Tang Center (E51)
70 Memorial Drive
Cambridge, MA 02139

DIMENSIONS Project Kick-Off

Hi Everyone:

Earlier this month I was in Morehead City at the UNC Institute of Marine Sciences for the kick-off meeting for our project on cyanobacteria in Lake Taihu (see my September 2012 post). It was a very productive visit. From a modeler’s perspective this project is exciting because it includes a lot of relevant and exciting observations not commonly available (e.g., ammonia regeneration, nifH gene expression, 14/15N isotope tracing, etc.). These will be a challenge to integrate in the model, but that is the fun part. It is also exciting to work on such an important problem, affecting the drinking water of millions of people. Here is a picture (from Paerl et al., 2011):

This project will keep us busy for a while!

Besides that, chairing a faculty search and teaching two classes is keeping me pretty busy this semester...

Best regards,
Ferdi

Bigelow Visit & ASLO Talk & Charles River Workshop

Hello Friends,

Last week I was at the Bigelow Lab (http://www.bigelow.org/) for a seminar. My visit was hosted by Ben Twining and Ramunas Stepanauskas. I really enjoyed the visit. One thing that stuck with me is the single cell genomics work Ramunas is doing. It turns out that cells of the same species (judged by 16S rRNA similarity) and from the same drop of water, typically (actually, apparently always) have different DNA. I always thought they would be the same, except for a rare mutation here and there. So are microbes as different as people? Have to do some more thinking about this... but - of course - as an individual-based modeler, I see a lot of opportunity for using IBMs here. “Single cell genomics is to metagenomics what individual-based modeling is to population-level modeling”?

Visit our presentations at ASLO! Neil Fredrick will present a talk entitled “EXPLORING MECHANISMS OF P CONTENT HETEROGENEITY IN CULTURED PHYTOPLANKTON USING AGENT-BASED MODELING” in session GS08A Plankton Ecology - Phytoplankton on Feb. 19. Here is a link: http://www.sgmeet.com/aslo/neworleans2013/viewabstract2.asp?AbstractID=10781
And John Berges will present “DIVERSE CAUSES OF CELL DEATH IN PHYTOPLANKTON IN SMALL FRESHWATER ECOSYSTEMS” in session SS79 Phytoplankton interactions in aquatic ecosystems. Here is a link:
http://www.sgmeet.com/aslo/neworleans2013/viewabstract2.asp?AbstractID=11365

We had our 3rd Charles River Water Quality Workshop last week, which was attended by 30 people. This is an annual event where we bring together people doing research on the river and share results in an informal setting. The agenda and presentation slides are available online here:
http://thecharles.org/2013WaterQualityWorkshopPresentations.html

Best regards,
Ferdi