earth and environmental sciences

Rast-Holbrook Seminar

4:00-4:25 Dr. Adam Milewski, Assistant Professor of Geology, University of Georgia, "The Past, Present, and Future of Water Resources in the Middle East and North Africa Region"
4:30-4:55 Dr. Neda Zawahri, Associate Professor of Political Science, Cleveland State University, "Management of Transboundary Rivers in the Middle East"
5:00-5:25 Discussion moderated by Dr. Alan Fryar

Date: 
Thursday, January 29, 2015 - 4:00pm
Location: 
303 Sloane

Morocco, Maps, and Precipitation: The NSF Grant with Ben Currens

In the summer of 2014, several undergraduate and graduate students from the College of Arts and Sciences received a grant from the National Science Foundation. This NSF grant gave them the means to pursue research in various fields as they explored their interests and prepared for their potential futures. In this podcast, we speak to Ben Currens, a graduate student in the Earth and Environmental Science Department. Listen in as Currens discusses his experiences with research and the unexpected turns that he has found along the way.

This podcast was produced by Casey Hibbard
 

Creative Commons License
Morocco, Maps, and Precepitation: The NSF Grant with Ben Currens by UK College of Arts & Sciences is licensed under a Creative Commons Attribution 4.0 International License.

THE CYCLE OF EROSION

 

Out on the trails of Shaker Village at Pleasant Hill, Kentucky, this morning, I got to thinking about William Morris Davis’ “cycle of erosion” conceptual model (also called the geographical or geomorphological cycle). The drive-by, oversimplified version is that landscape evolution starts with uplift of a more-or-less planar, low relief surface. Weathering and erosion goes to work, and results in an initial stage of increasing relief as streams carve valleys, and slope processes operate on the slopes thereby created. Eventually, however, as the streams begin to approach base level, a new stage of decreasing relief begins as hilltops and drainage divides are lowered and valleys infilled. This continues until the entire landscape is about as close to baselevel as the geophysics of mass transport will allow, creating a low-relief, almost-planar surface called a peneplain. At some point a new episode of uplift occurs and the cycle begins anew.

I was thinking of this because many landscapes in the world, like the one I was viewing this morning, do give the impression of a dissected plateau or a low-relief surface into which denudational processes have cut.

HYDROPEDOLOGY: FLUX-STRUCTURE INTERACTIONS

Subfields such as biogeomorphology, ecohydrology, geoecology, soil geomorphology are areas of overlap between disciplines and subdisciplines. They are governed by the paradigms of the overlapping fields, and fit more or less comfortably within, and at the boundaries of, those fields. They do not have an independent paradigm or conceptual framework (which in no way reduces their importance or vitality).

Landscape ecology, by contrast, has developed its own paradigm—pattern, process, scale—that is independent from mainstream ecology, biogeography, and geospatial analysis.

Does, or can, hydropedology have such an independent paradigm? Is its development best served by, say, the ecohydrology or soil geomorphology model as an overlap field dominated by existing paradigms of pedology and hydrology? Or is a landscape ecology, separate paradigm direction more appropriate?

NATURAL SELECTION

 

Natural selection is most familiar with respect to Darwinian evolution. However, though some biologists will argue that selection acts only on genes, this is a very narrow and restricted view. Selection operates on a variety of environmental phenomena, and at a variety of scales. In hydrology and geomorphology, the principle of gradient selection dictates that the most efficient flow paths are preferred over less efficient ones, and that these paths tend to be reinforced. That’s why water flows organize themselves into channels (more efficient than diffuse flows), and channels into networks. The principle of resistance selection in geomorphology is simply that more resistant features will persist while less resistant ones will be removed more quickly. Thus geomorphic processes select for certain forms and features and against others. Among others, Gerald Nanson, Rowl Twidale, and Luna Leopold have written on selection in geomorphology, and Henry Lin, among others, in hydrology.

 

Principle of gradient selection at work--Board Camp Creek, Arkansas

Finding Faults: Inside Sean Bemis' Research

Sean Bemis put his hands together side by side to demonstrate two plates of the earth’s crust with a smooth boundary running between them. But that boundary is not always smooth and those plates do not always sit together neatly, which makes the earth’s crust a dynamic and complex surface.

Undergraduate Assistants Help Freshmen Transition to Life as STEMCats

ANASTAMOSING CHANNELS

Recently published in Earth Surface Processes & Landforms: Anastamosing Channels in the Lower Neches River Valley, Texas. The abstract is below: 

 

Active and semi-active anastomosing Holocene channels upstream of the delta in the lower valley of the meandering Neches River in southeast Texas represent several morphologically distinct and hydrologically independent channel systems. These appear to have a common origin as multi-thread crevasse channels strongly influenced by antecedent morphology. Levee breaching leads to steeper cross-valley flows toward floodplain basins associated with Pleistocene meander scars, creating multi-thread channels that persist due to additional tributary contributions and ground water inputs. Results are consistent with the notion of plural systems where main channels, tributaries, and sub-channels may have different morphologies and hydrogeomorphic functions. The adjacent Trinity and Sabine Rivers have similar environmental controls, yet the Trinity lacks evidence of extensive anastomosing channels on its floodplain, and those of the Sabine appear to be of different origin. The paper highlights the effects of geographical and historical contingency and hydrological idiosyncrasy.

 

TELECONNECTIVITY

 

Last month the climatologist Justin Maxwell from Indiana University gave an interesting talk at our department about drought-busting tropical cyclones. In his talk, and in conversations before and after with our physical geography crew, he had some interesting things to say about climate teleconnections involving mainly sea surface temperature and pressure patterns such as ENSO, NAO, etc. If teleconnections and the various acronyms are unfamiliar, check out the National Climatic Data Center’s teleconnections page: http://www.ncdc.noaa.gov/teleconnections/

PLACE SIMILARITY

I've thought, written, and talked a lot about the need to incorporate geographical and historical contingency--that is, idiosyncratic characteristics of place and history--in geosciences, in addition to (not instead of!) general or universal laws. I've also emphasized the fact that places and environmental systems have elements of uniqueness. This leads to the issue of how to measure or assess place similarity (or the similarity of different, e.g., landscapes, ecosystems, plant communities, soils, etc.). This is a way of thinking about this problem, dressed up with some formal mathematical symbolism. Though I'm personally pretty informal, I'm a big believer in formal statements in science, as it makes arguments at least partly independent of linguistic skills (or lack thereof). 

 

 

 

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