Geological evolution of the Mississippi River into the Anthropocene

2021 ◽  
pp. 205301962110455
Author(s):  
Catherine Russell ◽  
Colin N Waters ◽  
Stephen Himson ◽  
Rachael Holmes ◽  
Annika Burns ◽  
...  

The Mississippi River maintains commercial and societal networks of the USA along its >3700 km length. It has accumulated a fluvial sedimentary succession over 80 million years. Through the last 11,700 years of the Holocene Epoch, the wild river shaped the landscape, models of which have become classic in geological studies of ancient river strata. Studies of the river were led by the need to develop infrastructure and to search for hydrocarbons, through which, these models have become quite sophisticated. However, whilst the models demonstrate how the wild river behaves, a monumental shift in fundamental controls on the entire fluvial system, broadly coinciding with the proposed mid-20th century onset of the Anthropocene Epoch, has generated new geological patterns that are becoming globally ubiquitous, and which the Mississippi River typifies. As such, whilst classic Holocene river models may be compared to human-modified systems such as the Lower Mississippi River (and others worldwide), locally the models may now only directly apply to its fossilized components preserved in the sub-surface. Such river models need adapting to better understand the present dynamics, and future evolution of these landscapes.

Author(s):  
Brittany M. Cleary ◽  
Megan E. Romano ◽  
Celia Y. Chen ◽  
Wendy Heiger-Bernays ◽  
Kathryn A. Crawford

Abstract Purpose of Review Our comparative analysis sought to understand the factors which drive differences in fish consumption advisories across the USA — including exposure scenarios (acute and chronic health risk, non-cancer and cancer health endpoints), toxicity values (reference dose, cancer slope factor, acute tolerance level), and meal size and bodyweight assumptions. Recent Findings Fish consumption provides essential nutrients but also results in exposure to contaminants such as PCBs and methylmercury. To protect consumers from the risks of fish contaminants, fish consumption advisories are established, most often by state jurisdictions, to estimate the amount of a certain fish species a person could consume throughout their lifetime without harm. However, inconsistencies in advisories across the USA confuse consumers and undermine the public health goals of fish advisory programs. To date, no rigorous comparison of state and national fish consumption advisories has been reported. Summary Our work identifies discrepancies in key assumptions used to derive risk-based advisories between US states, reflecting differences in the interpretation of toxicity science. We also address the implications for these differences by reviewing advisories issued by contiguous states bordering two waterbodies: Lake Michigan and the Lower Mississippi River. Our findings highlight the importance of regional collaboration when issuing advisories, so that consumers of self-caught fish are equipped with clear knowledge to make decisions to protect their health.


2008 ◽  
Vol 2008 (1) ◽  
pp. 7-36 ◽  
Author(s):  
Rolf Elberfeld

In the 20th century the European sciences have tried in different ways to develop post-colonial forms of knowledge. Since the 1920s, under headings such as »intercultural«, »multicultural« and »transcultural«, discourses have arisen in the USA and in Europe in which, until the present, new perspectives and structures in the sciences have developed. The article offers, on one hand, a discourse analysis of these three headings until 1980 and makes clear by way of examples how complicated and deep the challenges are for knowledge discourses in Europe within the scope of the research perspective of »interculturality«.


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