scholarly journals A brief history and summary of the effects of river engineering and dams on the Mississippi River system and delta

Circular ◽  
2012 ◽  
Author(s):  
Jason S. Alexander ◽  
Richard C. Wilson ◽  
W. Reed Green
2008 ◽  
Vol 35 (23) ◽  
Author(s):  
Nicholas Pinter ◽  
Abebe A. Jemberie ◽  
Jonathan W. F. Remo ◽  
Reuben A. Heine ◽  
Brian S. Ickes

2013 ◽  
Vol 37 (3) ◽  
pp. 422-431 ◽  
Author(s):  
William L. Graf

James C. Knox’s 1977 paper “Human Impacts on Wisconsin Stream Channels,” published in the Annals of the Association of American Geographers, was a key component of a suite of three papers by him defining the response of rivers to the introduction and management of agriculture and to climate change. In this paper he used the Driftless Area of southwest Wisconsin as a laboratory where he could define fluvial responses by their sedimentary signatures in floodplain deposits. Land-use records dating back to the early 19th century along with shorter climate records provided his understanding of the drivers of change. He found that floods increased as an outcome of land-cover change. Upstream tributaries became wider and shallower as coarse deposits limited their adjustments, while main stem channels became narrower and deeper. His paper reflected the influence of his graduate advisor and especially of prominent faculty colleagues at the University of Wisconsin from fields ranging from soils and climatology to geomorphology and history. The paper was the subject of considerable debate in the professional community, but it remains a much-cited example of Knox’s work in unraveling the Quaternary and Holocene history of rivers of the Driftless Area and by extension the upper Mississippi River system.


Fact Sheet ◽  
2017 ◽  
Author(s):  
Jayme M. Stone ◽  
Jenny L. Hanson ◽  
Stephanie R. Sattler

<em>Abstract</em>.—The black carp <em>Mylopharyngodon piceus </em>is a large (>1 m long) riverine fish from eastern Asia introduced into the United States via the aquaculture industry. A wild population has been present in the lower Mississippi River basin since the early 1990s, but little is known about the ecological effect of black carp in invaded environments. In its native range, black carp feed almost exclusively on mollusks. In U.S. waters, they likely prey on native mussels, but few wild-caught specimens have been examined by biologists and all have had empty gastrointestinal tracts. In lieu of stomach content data, we examined isotopic values (δ<sup>13</sup>C and δ <sup>15</sup>N) and mercury (Hg) concentrations in muscle tissue of black carp and 10 other large nonnative and native fish species captured in the Red–Atchafalaya River system of Louisiana, USA. Trophic position estimates derived from δ <sup>15</sup>N values ranged from 2.0 for grass carp <em>Ctenopharyngodon idella </em>to 4.8 for blue catfish <em>Ictalurus furcatus </em>and flathead catfish <em>Pylodictis olivaris</em>. Adult black carp had a δ <sup>15</sup>N value (13.2‰), indicating a trophic level of 3.5. Mean total Hg concentrations ranged from 0.02 µg/g in grass carp to 0.27 µg/g in bigmouth buffalo <em>Ictiobus cyprinellus</em>, in black carp 0.17 µg/g; Hg increased with increasing δ <sup>15</sup>N, indicating biomagnification. The limited numbers of taxa and small samples sizes, as well as constraints in methods used, do not allow confirmation that wild black carp are consuming native mollusks. However, our stable isotope results do provide evidence that its diet is similar to other large fish species inhabiting the Red–Atchafalaya system considered to be benthic invertivores, including some known to prey on freshwater mollusks (i.e., smallmouth buffalo <em>I. bubalus </em>and nonnative common carp <em>Cyprinus carpio</em>).


2014 ◽  
Vol 80 (23) ◽  
pp. 7186-7195 ◽  
Author(s):  
Colin R. Jackson ◽  
Justin J. Millar ◽  
Jason T. Payne ◽  
Clifford A. Ochs

ABSTRACTThe different drainage basins of large rivers such as the Mississippi River represent interesting systems in which to study patterns in freshwater microbial biogeography. Spatial variability in bacterioplankton communities in six major rivers (the Upper Mississippi, Missouri, Illinois, Ohio, Tennessee, and Arkansas) of the Mississippi River Basin was characterized using Ion Torrent 16S rRNA amplicon sequencing. When all systems were combined, particle-associated (>3 μm) bacterial assemblages were found to be different from free-living bacterioplankton in terms of overall community structure, partly because of differences in the proportional abundance of sequences affiliated with major bacterial lineages (Alphaproteobacteria,Cyanobacteria, andPlanctomycetes). Both particle-associated and free-living communities ordinated by river system, a pattern that was apparent even after rare sequences or those affiliated withCyanobacteriawere removed from the analyses. Ordination of samples by river system correlated with environmental characteristics of each river, such as nutrient status and turbidity. Communities in the Upper Mississippi and the Missouri and in the Ohio and the Tennessee, pairs of rivers that join each other, contained similar taxa in terms of presence-absence data but differed in the proportional abundance of major lineages. The most common sequence types detected in particle-associated communities were picocyanobacteria in theSynechococcus/Prochlorococcus/Cyanobium(Syn/Pro) clade, while free-living communities also contained a high proportion of LD12 (SAR11/Pelagibacter)-likeAlphaproteobacteria. This research shows that while different tributaries of large river systems such as the Mississippi River harbor distinct bacterioplankton communities, there is also microhabitat variation such as that between free-living and particle-associated assemblages.


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