As Prof. Laura Triplett’s National Science Foundation-funded project continues, she and her 2013 summer research students traveled to the Platte River in Nebraska one last time. Dr. Karin Kettenring (Utah State University), a co-investigator on the project, met our group there. The Platte River has undergone dramatic alterations in the past 100 years, from large reductions in flow, to invasion by non-native species, to aggressive management attempts to restore the river to some sort of natural equilibrium. Below, the Gustavus crew sits in front of a patch of dead Phragmites australis, a non-native 10-foot tall grass. Though it was killed by herbicides last year, the plants’ thick rhizomes and roots — visible under our feet — are still holding this sandy river island together, preventing the river from assuming its more ‘natural’ shape. From left: Emily Ford (Geology ’15), Laura, Rachel Mohr (Geology ’16) and Zach VanOrsdel (Geology ’15).
Although the Platte is again experiencing a very dry year due to low snowfall in its Rocky Mountain headwaters, we did need the Environmental Studies program dinghy to access two sites:
Usually, we were able to just wade across channels, as Laura and Karin are shown doing here. Karin was impressed by (and nervous about) the expensive high-precision GPS unit we had rented for the week, which she is holding.
Note the killed Phragmites in the far background, and young shoots of resurgent live Phrag in the middle of the photo. It’s pernicious stuff.
Most of our time was spent poring over shovelfuls of sediment, much of which we’ve brought back to Gustavus for silica and particle size analysis. We hope to determine how vegetation has changed the amount of silica, a natural element and necessary nutrient for some algae, that is flowing down the river. See earlier blog posts for more info on the project. Again, killed Phrag is visible in the background but resurgent shoots are visible on the far right.
By the end of the week, Zach was ready to destroy Phragmites by whatever means necessary. Die, Phrag! (And, an inevitable geological aside: note nicely-anabranching sandbed river, all vegetation destroyed by herbicide, disc-ing and bulldozing.)
