skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Amazon River’s Ecosystem: Where Land Meets the Sea

Abstract

What happens to plant matter on its journey down the Amazon River to the Atlantic Ocean? One research group investigated the region where river and ocean meet to fill in this part of the story.

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1421343
Report Number(s):
PNNL-SA-128535
Journal ID: ISSN 2324-9250; EOSTAJ
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Eos, Transactions American Geophysical Union (Online); Journal Volume: 99
Country of Publication:
United States
Language:
English
Subject:
Amazon; aquatic; bacteria; biogeochemistry; carbon; carbon dioxide; climate change; coastal; continuum; decomposition; dissolved organic carbon; ecosystem; estuarine; export; cycling; emission; ecotone; flux; global change; greenhouse gas; marine; metagenome; methane; microbial; organic; outgassing; remote sensing; rivers; tidal; tidal river; terrestial aquatic interface; wetland

Citation Formats

Ward, Nicholas, Sawakuchi, Henrique, and Richey, Jeffrey. The Amazon River’s Ecosystem: Where Land Meets the Sea. United States: N. p., 2018. Web. doi:10.1029/2018EO088573.
Ward, Nicholas, Sawakuchi, Henrique, & Richey, Jeffrey. The Amazon River’s Ecosystem: Where Land Meets the Sea. United States. doi:10.1029/2018EO088573.
Ward, Nicholas, Sawakuchi, Henrique, and Richey, Jeffrey. Thu . "The Amazon River’s Ecosystem: Where Land Meets the Sea". United States. doi:10.1029/2018EO088573.
@article{osti_1421343,
title = {The Amazon River’s Ecosystem: Where Land Meets the Sea},
author = {Ward, Nicholas and Sawakuchi, Henrique and Richey, Jeffrey},
abstractNote = {What happens to plant matter on its journey down the Amazon River to the Atlantic Ocean? One research group investigated the region where river and ocean meet to fill in this part of the story.},
doi = {10.1029/2018EO088573},
journal = {Eos, Transactions American Geophysical Union (Online)},
number = ,
volume = 99,
place = {United States},
year = {Thu Jan 18 00:00:00 EST 2018},
month = {Thu Jan 18 00:00:00 EST 2018}
}
  • As the world's population has grown and moved toward the sea, the oceanic effects of this progression have been felt first and most acutely in the estuary. Perhaps this should come as no surprise, for the estuary is where the river, with all its waterborne materials draining off the altered landscape, meets the sea. But there is more than proximity at work here. The estuary is nearly a world unto itself, buffered from a strong marine influence by a controlled communication with the ocean, and protected by enclosing coastal boundaries. Within this domain, the estuary's unique water motion retains andmore » recycles nutrients essential to living organisms, inducing the richest productivity per square kilometer on the earth's surface. Labeled the protein factory' by writer H.L. Mencken, an estuary is made bountiful through the workings of physical, chemical, and biological engines in complex and sometimes mysterious balance. These balances can be very delicate, and humans can tilt and dramatically shift the outcome, clarity to the point where a diver literally cannot see a hand at arm's length. This feature is a result of the estuarine circulation, where fine-grained sediment delivered by the river is retained and resuspended many times by the ebb and flow of tidal currents. Because many toxic substances are attracted to the surfaces of these sediment particles, some fear that such trapping processes created by the two-layer flow might produce local regions with unacceptably high levels of contamination.« less
  • The Tennessee Valley Authority (TVA) has started the next phase of a project that could help solve one of the most viewing solid waste disposal problems in the USA. The disposal of used automobile tires. TVA began burning about 1250 tons of shredded tires mixed with crushed coal at its Allen plant near Memphis, Tennessee. Of the 300-MW Allen unit 1, one of the three units at the 900-MW station, TVA is mixing about 20 tons of shredded tires with 500 tons of coal per hour, or a 4% mixture. Made mostly of petroleum, tires have good fuel characteristics. Theymore » have a higher BTU value than coal, burn at a higher temperature, and burn cleaner. The first phase of the TVA test program was designed to show whether tires may be used as a fuel. Some results of the tests are presented and discussed.« less
  • The author sees unfathomable problems in the shadows of proposals to amend the Public Utility Holding Company Act (PUHCA). His concerns lead him to insist on retaining key protections of PUHCA and adding certain protections through state regulation. State regulators are addressing myriad new and complex issues, many of which have their genesis in policy shifts at the federal level. Debate was launched when the Federal Energy Regulatory Commission issued its Notice of inquiry proceeding (NOPR). The NOPRs contemplated fundamental change in the structure of the industry and regulation. This article examines the assumptions underlying the call for PUHCA reformmore » and to discuss the fundamental policy issues which must be considered before any attempt is made to fix a major consumer protection statute which, may not be broken.« less
  • The desire to improve and expand the scope of clinical magnetic resonance imaging (MRI) has prompted the search for contrast agents of higher efficiency. The development of better agents requires consideration of the fundamental coordination chemistry of the gadolinium(III) ion and the parameters that affect its efficacy as a proton relaxation agent. In optimizing each parameter, other practical issues such as solubility and in vivo toxicity must also be addressed, making the attainment of safe, high-relaxivity agents a challenging goal. Here we present recent advances in the field, with an emphasis on the hydroxypyridinone family of Gd{sup III} chelates.
  • Although recent research suggests that contaminant plumes behave as geobatteries that produce an electrical current in the ground, no associated model exists that honors both geophysical and biogeochemical constraints. Here, we develop such a model to explain the two main electrochemical contributions to self-potential signals in contaminated areas. Both contributions are associated with the gradient of the activity of two types of charge carriers, ions and electrons. In the case of electrons, bacteria act as catalysts for reducing the activation energy needed to exchange the electrons between electron donor and electron acceptor. Possible mechanisms that facilitate electron migration include ironmore » oxides, clays, and conductive biological materials, such as bacterial conductive pili or other conductive extracellular polymeric substances. Because we explicitly consider the role of biotic processes in the geobattery model, we coined the term 'biogeobattery'. After theoretical development of the biogeobattery model, we compare model predictions with self-potential responses associated with laboratory and field-scale conducted in contaminated environments. We demonstrate that the amplitude and polarity of large (>100 mV) self-potential signatures requires the presence of an electronic conductor to serve as a bridge between electron donors and acceptors. Small self-potential anomalies imply that electron donors and electron acceptors are not directly interconnected, but instead result simply from the gradient of the activity of the ionic species that are present in the system.« less