Understanding and managing urban aquatic ecosystems has to begin with good information about their distribution and about characteristics like size and shape (hydrography). We've just received word that our paper on this topic, led by post-doc Meredith Steele, has been accepted for publication in Ecological Applications! One simple thing that makes this paper significant is the spatial extent of Meredith's analysis (100 cities across the whole US). A second simple thing about this paper is what the data show: urban water bodies (lakes, ponds, wetlands) are of moderate size. That is, in comparison to undeveloped land outside cities, there are fewer very large and fewer very small water bodies. The more complicated thing we want to know is how these differences arise. One possibility is that cities are located near particular types of water bodies. A second possibility is that, during urban development, we remove small (and large?) water bodies, and build medium-sized ones. We use some subtler patterns in our data to distinguish among these processes, and ask how their importance might change over time. This paper is the first of several papers Meredith has in review or in prep that will deal with other scales and other aspects of urban hydrographic change. Very exciting! And congratulations Meredith!
Congratulations are due to Ewan Isherwood, who successfully defended his MS thesis this morning at FIU! Ewan's research addresses the distinctness of vegetation communities (ridges and sloughs) in the Florida Everglades, with a particular focus on how these these distinct communities become more blended as a result of hydrologic modification and microtopographic flattening. To do this, Ewan developed statistical proxies of distinctness using multivariate techniques, and applied them across our Everglades-wide sampling regime.
A few weeks ago, Dr. Todd Kana delivered a new instrument to the River Center. The Membrane Inlet Mass Spectrometer, which Todd designs and builds, measures dissolved gases directly from water samples. We had one of these instruments in our lab at FIU, and used it to study denitrification in the Floridan Aquifer and in spring-fed and blackwater rivers.
Yesterday, Todd returned to us to train about 8 people from the River Center and other labs on the use of the new instrument, which is a slightly different model than the old MIMS. We also had lunch with about a dozen people where we discussed the different applications of the MIMS, including the different gases it can measure and the different kinds of samples it can measure (air, water; field samples, in line experiments, etc.). We are very excited to have this new capability in the lab, and look forward to all of the neat things we will learn with it!
This is the homepage of the Heffernan Lab at Duke University. Here you can find all sorts of information about our research, teaching, and outreach. If you have any questions, contact Dr. Heffernan.
Dr. Jim Heffernan
I am an Assistant Professor in the Nicholas School of the Environment at Duke University. My research is focused on the causes and consequences of major changes in ecosystem structure, mostly in streams and wetlands.
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