Level IV Ecoregions of Vermont

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Illinois

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Louisiana

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Massachusetts

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Wyoming

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Texas

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Oregon

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Colorado

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Missouri

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Alabama

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Arizona

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Nebraska

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Utah

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Alabama

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Wisconsin

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Connecticut

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Massachusetts

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Nevada

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Pennsylvania

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Nebraska

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Arkansas

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Idaho

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Texas

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Oregon

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Georgia

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Vermont

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Indiana

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Virginia

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Minnesota

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Kentucky

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Florida

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Mississippi

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Washington

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Kentucky

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Connecticut

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Maryland

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Montana

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Idaho

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Michigan

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Georgia

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Florida

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Nevada

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Kansas

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Michigan

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Maine

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Ohio

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Iowa

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Washington

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Delaware

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Iowa

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Alaska

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. The ecoregions of Alaska are a...

Level IV Ecoregions of California

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Arkansas

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Illinois

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Colorado

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Pennsylvania

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Oklahoma

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Utah

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Oklahoma

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Ohio

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Minnesota

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Conservation status of imperiled North American freshwater and diadromous fishes

Science.gov (United States)

Howard L. Jelks; Stephen J. Walsh; Noel M. Burkhead; Salvador Contreras-Balderas; Edmundo Diaz-Pardo; Dean A. Hendrickson; John Lyons; Nicholas E. Mandrak; Frank McCormick; Joseph S. Nelson; Steven P. Plantania; Brady A. Porter; Claude B. Renaud; Juan Jacobo Schmitter-Soto; Eric B. Taylor; Melvin L. Jr. Warren

2008-01-01

This is the third compilation of imperiled (i.e., endangered, threatened, vulnerable) plus extinct freshwater and diadromous fishes of North America prepared by the American Fisheries Society?s Endangered Species Committee. Since the last revision in 1989, imperilment of inland fishes has increased substantially. This list includes 700 extant taxa representing 133...

A simple web-based tool to compare freshwater fish data collected using AFS standard methods

Science.gov (United States)

Bonar, Scott A.; Mercado-Silva, Norman; Rahr, Matt; Torrey, Yuta T.; Cate, Averill

2016-01-01

The American Fisheries Society (AFS) recently published Standard Methods for Sampling North American Freshwater Fishes. Enlisting the expertise of 284 scientists from 107 organizations throughout Canada, Mexico, and the United States, this text was developed to facilitate comparisons of fish data across regions or time. Here we describe a user-friendly web tool that automates among-sample comparisons in individual fish condition, population length-frequency distributions, and catch per unit effort (CPUE) data collected using AFS standard methods. Currently, the web tool (1) provides instantaneous summaries of almost 4,000 data sets of condition, length frequency, and CPUE of common freshwater fishes collected using standard gears in 43 states and provinces; (2) is easily appended with new standardized field data to update subsequent queries and summaries; (3) compares fish data from a particular water body with continent, ecoregion, and state data summaries; and (4) provides additional information about AFS standard fish sampling including benefits, ongoing validation studies, and opportunities to comment on specific methods. The web tool—programmed in a PHP-based Drupal framework—was supported by several AFS Sections, agencies, and universities and is freely available from the AFS website and fisheriesstandardsampling.org. With widespread use, the online tool could become an important resource for fisheries biologists.

Chihuahuan Deserts Ecoregion: Chapter 27 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Ruhlman, Jana; Gass, Leila; Middleton, Barry

2012-01-01

The Chihuahuan Desert is the largest of the North American deserts, extending from southern New Mexico and Texas deep into Mexico, with approximately 90 percent of its area falling south of the United States–Mexico border (Lowe, 1964, p. 24). The Chihuahuan Deserts Ecoregion covers approximately 174,472 km2 (67,364 mi2) within the United States, including much of west Texas, southern New Mexico, and a small portion of southeastern Arizona (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is generally oriented from northwest to southeast, with the Madrean Archipelago Ecoregion to the west; the Arizona/New Mexico Mountains, Arizona/New Mexico Plateau, Southwestern Tablelands, and Western High Plains Ecoregions to the north; and the Edwards Plateau and Southern Texas Plains Ecoregions to the east (fig. 1).

Level IV Ecoregions of New York

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of New Jersey

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of New Mexico

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of New Hampshire

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of North Dakota

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of West Virginia

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of New Jersey

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of New York

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of South Dakota

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of North Carolina

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of New Hampshire

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of New Mexico

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of North Dakota

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of South Carolina

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of North Carolina

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level IV Ecoregions of Rhode Island

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of Rhode Island

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Level III Ecoregions of South Dakota

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...

Wyoming Basin Rapid Ecoregional Assessment

Science.gov (United States)

Carr, Natasha B.; Melcher, Cynthia P.

2015-08-28

The Wyoming Basin Rapid Ecoregional Assessment was conducted in partnership with the Bureau of Land Management (BLM). The overall goals of the BLM Rapid Ecoregional Assessments (REAs) are to identify important ecosystems and wildlife habitats at broad spatial scales; identify where these resources are at risk from Change Agents, including development, wildfire, invasive species, disease and climate change; quantify cumulative effects of anthropogenic stressors; and assess current levels of risk to ecological resources across a range of spatial scales and jurisdictional boundaries by assessing all lands within an ecoregion. There are several components of the REAs. Management Questions, developed by the BLM and stakeholders for the ecoregion, identify the regionally significant information needed for addressing land-management responsibilities. Conservation Elements represent regionally significant species and ecological communities that are of management concern. Change Agents that currently affect or are likely to affect the condition of species and communities in the future are identified and assessed. REAs also identify areas that have high conservation potential that are referred to as “large intact areas.” At the ecoregion level, the ecological value of large intact areas is based on the assumption that because these areas have not been greatly altered by human activities (such as development), they are more likely to contain a variety of plant and animal communities and to be resilient and resistant to changes resulting from natural disturbances such as fire, insect outbreaks, and disease.

Level III Ecoregions of EPA Region 8

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions for EPA Administrative Regions were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the...

Level IV Ecoregions of EPA Region 8

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions for EPA Administrative Regions were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the...

Level IV Ecoregions of EPA Region 9

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions for EPA Administrative Regions were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the...

Level III Ecoregions of EPA Region 9

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions for EPA Administrative Regions were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the...

Level IV Ecoregions of EPA Region 5

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level IV Ecoregions of EPA Region 10

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level IV Ecoregions of EPA Region 2

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level IV Ecoregions of EPA Region 3

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level III Ecoregions of EPA Region 2

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level III Ecoregions of EPA Region 4

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level IV Ecoregions of EPA Region 7

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level IV Ecoregions of EPA Region 6

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level IV Ecoregions of EPA Region 1

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level III Ecoregions of EPA Region 1

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level III Ecoregions of EPA Region 10

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level IV Ecoregions of EPA Region 4

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level III Ecoregions of EPA Region 3

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level III Ecoregions of EPA Region 7

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level III Ecoregions of EPA Region 5

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Level III Ecoregions of EPA Region 6

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions by EPA region were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality,...

Effects and empirical critical loads of Nitrogen for ecoregions of the United States

Science.gov (United States)

Pardo, Linda H.; Robin-Abbott, Molly J.; Fenn, Mark E.; Goodale, Christine L.; Geiser, Linda H.; Driscoll, Charles T.; Allen, Edith B.; Baron, Jill S.; Bobbink, Roland; Bowman, William D.; Clark, C M; Emmett, B.; Gilliam, Frank S; Greaver, Tara L.; Hall, Sharon J; Lilleskov, Erik A.; Liu, Lingli; Lynch, Jason A.; Nadelhoffer, Knute J; Perakis, Steven; Stoddard, John L; Weathers, Kathleen C.; Dennis, Robin L.

2015-01-01

Human activity in the last century has increased nitrogen (N) deposition to a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. We synthesized current research relating atmospheric N deposition to effects on terrestrial and freshwater ecosystems in the United States, and estimated associated empirical critical loads of N for several receptors: freshwater diatoms, mycorrhizal fungi, lichens, bryophytes, herbaceous plants, shrubs, and trees. Biogeochemical responses included increased N mineralization and nitrification, increased gaseous N losses, and increased N leaching. Individual species, population, and community responses included increased tissue N, physiological and nutrient imbalances, increased growth, altered root-shoot ratios, increased susceptibility to secondary stresses, altered fire regime, shifts in competitive interactions and community composition, changes in species richness and other measures of biodiversity, and increases in invasive species. The range of critical loads of nutrient N reported for U.S. ecoregions, inland surface waters, and freshwater wetlands is 1–39 kg N ha−1 yr−1, spanning the range of N deposition observed over most of the country. The empirical critical loads of N tend to increase in the following sequence: diatoms, lichens and bryophytes, mycorrhizal fungi, herbaceous plants and shrubs, trees.

ROE Ecoregions Data

Data.gov (United States)

U.S. Environmental Protection Agency — This web service layer group contains multiple layers at various scale dependencies which enhances the cartographic display of ecoregion data. Each layer depicts...

Ecoregions and stream morphology in eastern Oklahoma

Science.gov (United States)

Splinter, D.K.; Dauwalter, D.C.; Marston, R.A.; Fisher, W.L.

2010-01-01

Broad-scale variables (i.e., geology, topography, climate, land use, vegetation, and soils) influence channel morphology. How and to what extent the longitudinal pattern of channel morphology is influenced by broad-scale variables is important to fluvial geomorphologists and stream ecologists. In the last couple of decades, there has been an increase in the amount of interdisciplinary research between fluvial geomorphologists and stream ecologists. In a historical context, fluvial geomorphologists are more apt to use physiographic regions to distinguish broad-scale variables, while stream ecologists are more apt to use the concept of an ecosystem to address the broad-scale variables that influence stream habitat. For this reason, we designed a study using ecoregions, which uses physical and biological variables to understand how landscapes influence channel processes. Ecoregions are delineated by similarities in geology, climate, soils, land use, and potential natural vegetation. In the fluvial system, stream form and function are dictated by processes observed throughout the fluvial hierarchy. Recognizing that stream form and function should differ by ecoregion, a study was designed to evaluate how the characteristics of stream channels differed longitudinally among three ecoregions in eastern Oklahoma, USA: Boston Mountains, Ozark Highlands, and Ouachita Mountains. Channel morphology of 149 stream reaches was surveyed in 1st- through 4th-order streams, and effects of drainage area and ecoregion on channel morphology was evaluated using multiple regressions. Differences existed (?????0.05) among ecoregions for particle size, bankfull width, and width/depth ratio. No differences existed among ecoregions for gradient or sinuosity. Particle size was smallest in the Ozark Highlands and largest in the Ouachita Mountains. Bankfull width was larger in the Ozark Highlands than in the Boston Mountains and Ouachita Mountains in larger streams. Width/depth ratios of the

Glacial cycles as an allopatric speciation pump in north-eastern American freshwater fishes.

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April, Julien; Hanner, Robert H; Dion-Côté, Anne-Marie; Bernatchez, Louis

2013-01-01

Allopatric speciation may be the principal mechanism generating new species. Yet, it remains difficult to judge the generality of this process because few studies have provided evidence that geographic isolation has triggered the development of reproductive isolation over multiple species of a regional fauna. Here, we first combine results from new empirical data sets (7 taxa) and published literature (9 taxa) to show that the eastern Great Lakes drainage represents a multispecies suture zone for glacial lineages of freshwater fishes with variable levels of genetic divergence. Second, we performed amplified fragment length polymorphism analyses among four pairs of lineages. Results indicate that lineages with relatively deep levels of mtDNA 5' COI (barcode) sequence divergence (>2%) developed strong reproductive barriers, while lineages with lower levels of divergence show weaker reproductive isolation when found in sympatry. This suggests that a threshold of 2% sequence divergence at mtDNA could be used as a first step to flag cryptic species in North American freshwater fishes. By describing different levels of divergence and reproductive isolation in different co-occurring fishes, we offer strong evidence that allopatric speciation has contributed significantly to the diversification of north-eastern American freshwater fishes and confirm that Pleistocene glacial cycles can be viewed as a 'speciation pump' that played a predominant role in generating biodiversity. © 2012 Blackwell Publishing Ltd.

Ecoregions of Kansas

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Kansas Data Access and Support Center — Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a...

Level III Ecoregions of the Mississippi Alluvial Plain

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U.S. Environmental Protection Agency — Ecoregions for the Mississippi Alluvial Plain were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in...

Level IV Ecoregions of the Mississippi Alluvial Plain

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U.S. Environmental Protection Agency — Ecoregions for the Mississippi Alluvial Plain were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in...

Ecoregions - ECOREGIONS_USGS_IN: Ecoregions, Levels III and IV, Indiana (U.S. Geological Survey, 1:250,000, Polygon Shapefile)

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NSGIC State | GIS Inventory — The following is excerpted from the metadata for OHIN_ECO: "The ecoregions shown here have been derived from Omernik (1987) and fr refinements of Omernik's framework...

Verification of a ‘freshwater-type’ life history variant of juvenile American shad in the Columbia River

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Wetzel, Lisa A.; Larsen, Kimberly A.; Parsley, Michael J.; Zimmerman, Christian E.

2011-01-01

American shad are native to the Atlantic coast of North America and were successfully introduced to the Pacific coast in the 1870s. They are now more abundant in the Columbia River than are its native salmon. As in their native range, Columbia River American shad are anadromous and have been assumed to solely exhibit an ‘ocean-type’ life history, characterized by a short period of juvenile rearing in freshwater, followed by seaward migration and saltwater entry before age-1, with sexually mature individuals returning to freshwater to spawn beginning at age-3. During October 2007, emigrating juvenile American shad were captured in the juvenile fish monitoring facility at Bonneville Dam (river kilometer 235) on the Columbia River. Their length frequencies revealed the presence of two modes; the lower mode averaged 77 mm fork length (FL) and the upper mode averaged 184 mm FL. A subsample of fish from each mode was aged using otoliths. Otoliths from the lower mode (n=10) had no annuli, indicating that they were all age-0, while otoliths from the upper mode (n=25) had one or two annuli, indicating that they were either age-1 or age-2, respectively. Spawning adults collected in June 2007 averaged 393 mm FL (range 305-460 mm; n=21) and were estimated to range in age from 3-6. Elemental analyses of juvenile and adult otoliths provide evidence for deviations from the typical migration pattern expected for this species, including extensive freshwater rearing of up to two years. This evidence shows that a ‘freshwater-type’ of juvenile American shad exists as year-round or transient residents in the Columbia River basin. The ecological role of this life history variant within the fish community is unknown.

Agro-ecoregionalization of Iowa using multivariate geographical clustering

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Carol L. Williams; William W. Hargrove; Matt Leibman; David E. James

2008-01-01

Agro-ecoregionalization is categorization of landscapes for use in crop suitability analysis, strategic agroeconomic development, risk analysis, and other purposes. Past agro-ecoregionalizations have been subjective, expert opinion driven, crop specific, and unsuitable for statistical extrapolation. Use of quantitative analytical methods provides an opportunity for...

Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States

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Pardo, L.H.; Fenn, M.E.; Goodale, C.L.; Geiser, L.H.; Driscoll, C.T.; Allen, E.B.; Baron, Jill S.; Bobbink, R.; Bowman, W.D.; Clark, C.M.; Emmett, B.; Gilliam, F.S.; Greaver, T.L.; Hall, S.J.; Lilleskov, E.A.; Liu, L.; Lynch, J.A.; Nadelhoffer, K.J.; Perakis, S.S.; Robin-Abbott, M. J.; Stoddard, J.L.; Weathers, K.C.; Dennis, R.L.

2011-01-01

Human activity in the last century has led to a significant increase in nitrogen (N) emissions and atmospheric deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the deposition of pollution that would be harmful to ecosystems is the determination of critical loads. A critical load is defined as the input of a pollutant below which no detrimental ecological effects occur over the long-term according to present knowledge. The objectives of this project were to synthesize current research relating atmospheric N deposition to effects on terrestrial and freshwater ecosystems in the United States, and to estimate associated empirical N critical loads. The receptors considered included freshwater diatoms, mycorrhizal fungi, lichens, bryophytes, herbaceous plants, shrubs, and trees. Ecosystem impacts included: (1) biogeochemical responses and (2) individual species, population, and community responses. Biogeochemical responses included increased N mineralization and nitrification (and N availability for plant and microbial uptake), increased gaseous N losses (ammonia volatilization, nitric and nitrous oxide from nitrification and denitrification), and increased N leaching. Individual species, population, and community responses included increased tissue N, physiological and nutrient imbalances, increased growth, altered root : shoot ratios, increased susceptibility to secondary stresses, altered fire regime, shifts in competitive interactions and community composition, changes in species richness and other measures of biodiversity, and increases in invasive species. The range of critical loads for nutrient N reported for U.S. ecoregions, inland surface waters, and freshwater wetlands is 1-39 kg N.ha -1.yr -1, spanning the range of N deposition observed over most of the country. The empirical critical loads for N tend to

Biodiversity, Urban Areas, and Agriculture: Locating Priority Ecoregions for Conservation

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Taylor Ricketts

2003-12-01

Full Text Available Urbanization and agriculture are two of the most important threats to biodiversity worldwide. The intensities of these land-use phenomena, however, as well as levels of biodiversity itself, differ widely among regions. Thus, there is a need to develop a quick but rigorous method of identifying where high levels of human threats and biodiversity coincide. These areas are clear priorities for biodiversity conservation. In this study, we combine distribution data for eight major plant and animal taxa (comprising over 20,000 species with remotely sensed measures of urban and agricultural land use to assess conservation priorities among 76 terrestrial ecoregions in North America. We combine the species data into overall indices of richness and endemism. We then plot each of these indices against the percent cover of urban and agricultural land in each ecoregion, resulting in four separate comparisons. For each comparison, ecoregions that fall above the 66th quantile on both axes are identified as priorities for conservation. These analyses yield four "priority sets" of 6-16 ecoregions (8-21% of the total number where high levels of biodiversity and human land use coincide. These ecoregions tend to be concentrated in the southeastern United States, California, and, to a lesser extent, the Atlantic coast, southern Texas, and the U.S. Midwest. Importantly, several ecoregions are members of more than one priority set and two ecoregions are members of all four sets. Across all 76 ecoregions, urban cover is positively correlated with both species richness and endemism. Conservation efforts in densely populated areas therefore may be equally important (if not more so as preserving remote parks in relatively pristine regions.

EPA Level III Ecoregions

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U.S. Environmental Protection Agency — The ecoregions shown here have been derived from Omernik (1987) and from refinements of Omernik's framework that have been made for other projects. These ongoing or...

Level III and IV Ecoregions of the Continental United States

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Information and downloadable maps and datasets for Level III and IV ecoregions of the continental United States. Ecoregions are areas of general similarity in the type, quality, and quantity of environmental resources.

U.S. Level III and IV Ecoregions (U.S. EPA)

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U.S. Environmental Protection Agency — This map service displays Level III and Level IV Ecoregions of the United States and was created from ecoregion data obtained from the U.S. Environmental Protection...

Determining ecoregional numeric nutrient criteria by stressor-response models in Yungui ecoregion lakes, China.

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Huo, Shouliang; Ma, Chunzi; Xi, Beidou; Tong, Zhonghua; He, Zhuoshi; Su, Jing; Wu, Fengchang

2014-01-01

The importance of developing numeric nutrient criteria has been recognized to protect the designated uses of water bodies from nutrient enrichment that is associated with broadly occurring levels of nitrogen/phosphorus pollution. The identification and estimation of stressor-response models in aquatic ecosystems has been shown to be useful in the determination of nutrient criteria. In this study, three methods based on stressor-response relationships were applied to determine nutrient criteria for Yungui ecoregion lakes with respect to total phosphorus (TP), total nitrogen (TN), and planktonic chlorophyll a (Chl a). Simple linear regression (SLR) models were established to provide an estimate of the relationship between a response variable and a stressor. Multiple linear regressions were used to simultaneously estimate the effect of TP and TN on Chl a. A morphoedaphic index (MEI) was applied to derive nutrient criteria using data from Yungui ecoregion lakes, which were considered as areas with less anthropogenic influences. Nutrient criteria, as determined by these three methods, showed broad agreement for all parameters. The ranges of numeric nutrient criteria for Yungui ecoregion lakes were determined as follows: TP 0.008-0.010 mg/L and TN 0.140-0.178 mg/L. The stressor-response analysis described will be of benefit to support countries in their numeric criteria development programs and to further the goal of reducing nitrogen/phosphorus pollution in China.

Ecoregions for Louisiana from EPA source data, Geographic NAD83, LOSCO (2004) [ecoregions_EPA_2004

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Louisiana Geographic Information Center — Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. By recognizing the spatial differences...

Investigation of floristic similarities between Taiwan and terrestrial ecoregions in Asia using GBIF data.

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Liao, Chi-Cheng; Chen, Chih-Hui

2017-12-01

Floristic compositions of non-endemic plants of continental islands were related to the neighboring continents because non-endemic plant species had historically migrated to continental islands from source areas. This study attempts to identify source areas of a continental island by means of floristic analysis and to assess possible migration routes on the basis of geographical distribution ranges of plants. Large quantities of angiosperm data records were downloaded from the Global Biodiversity Information Facility (GBIF). Similarity index and cluster analysis were used to identify the floristic similarities among 22 geographical localities of Taiwan (GLTs) and 34 terrestrial ecoregions in Asia. Geographical distribution ranges of non-endemic angiosperm species in Taiwan (NEASTs) were evaluated to mirror the possible migration routes from different source areas to Taiwan. There are 3275 angiosperm species in Taiwan derived from the dataset of GBIF. Among them, 847 are endemic and 2428 are NEASTs. Geographical distribution ranges of the 2428 NEASTs were categorized into 7 distribution groups. They were widely distribution from equator to Siberia (27 species), tropical ecoregions (345 species), tropical and subtropical ecoregions (663 species), tropical to temperate ecoregions (591 species), subtropical ecoregions (265 species), subtropical to temperate ecoregions (387 species), and temperate ecoregions (150 species). Results of similarity indices and cluster analysis demonstrated that high floristic similarities were observed among GLTs at lowland and southern Taiwan and tropical and subtropical ecoregions in Asia. GLTs at high mountains were assumed to have floristic similarity with temperate ecoregions in Asia, whereas the assumption was not supported by our analysis. It is partly because of that angiosperms with tropical and subtropical distributions extend their ranges from low to high elevations in Taiwan. Subtropical ecoregions at southern China and tropical

A segmentation approach for a delineation of terrestrial ecoregions

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Nowosad, J.; Stepinski, T.

2017-12-01

Terrestrial ecoregions are the result of regionalization of land into homogeneous units of similar ecological and physiographic features. Terrestrial Ecoregions of the World (TEW) is a commonly used global ecoregionalization based on expert knowledge and in situ observations. Ecological Land Units (ELUs) is a global classification of 250 meters-sized cells into 4000 types on the basis of the categorical values of four environmental variables. ELUs are automatically calculated and reproducible but they are not a regionalization which makes them impractical for GIS-based spatial analysis and for comparison with TEW. We have regionalized terrestrial ecosystems on the basis of patterns of the same variables (land cover, soils, landform, and bioclimate) previously used in ELUs. Considering patterns of categorical variables makes segmentation and thus regionalization possible. Original raster datasets of the four variables are first transformed into regular grids of square-sized blocks of their cells called eco-sites. Eco-sites are elementary land units containing local patterns of physiographic characteristics and thus assumed to contain a single ecosystem. Next, eco-sites are locally aggregated using a procedure analogous to image segmentation. The procedure optimizes pattern homogeneity of all four environmental variables within each segment. The result is a regionalization of the landmass into land units characterized by uniform pattern of land cover, soils, landforms, climate, and, by inference, by uniform ecosystem. Because several disjoined segments may have very similar characteristics, we cluster the segments to obtain a smaller set of segment types which we identify with ecoregions. Our approach is automatic, reproducible, updatable, and customizable. It yields the first automatic delineation of ecoregions on the global scale. In the resulting vector database each ecoregion/segment is described by numerous attributes which make it a valuable GIS resource for

Ecoregions of the conterminous United States: evolution of a hierarchical spatial framework

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Omernik, James M.; Griffith, Glenn E.

2014-01-01

A map of ecological regions of the conterminous United States, first published in 1987, has been greatly refined and expanded into a hierarchical spatial framework in response to user needs, particularly by state resource management agencies. In collaboration with scientists and resource managers from numerous agencies and institutions in the United States, Mexico, and Canada, the framework has been expanded to cover North America, and the original ecoregions (now termed Level III) have been refined, subdivided, and aggregated to identify coarser as well as more detailed spatial units. The most generalized units (Level I) define 10 ecoregions in the conterminous U.S., while the finest-scale units (Level IV) identify 967 ecoregions. In this paper, we explain the logic underpinning the approach, discuss the evolution of the regional mapping process, and provide examples of how the ecoregions were distinguished at each hierarchical level. The variety of applications of the ecoregion framework illustrates its utility in resource assessment and management.

EcoRegion Polygons, Nevada, 2007, ECOMAP

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U.S. Environmental Protection Agency — Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a...

Ecoregion-Based Conservation Planning in the Mediterranean: Dealing with Large-Scale Heterogeneity

Science.gov (United States)

Giakoumi, Sylvaine; Sini, Maria; Gerovasileiou, Vasilis; Mazor, Tessa; Beher, Jutta; Possingham, Hugh P.; Abdulla, Ameer; Çinar, Melih Ertan; Dendrinos, Panagiotis; Gucu, Ali Cemal; Karamanlidis, Alexandros A.; Rodic, Petra; Panayotidis, Panayotis; Taskin, Ergun; Jaklin, Andrej; Voultsiadou, Eleni; Webster, Chloë; Zenetos, Argyro; Katsanevakis, Stelios

2013-01-01

Spatial priorities for the conservation of three key Mediterranean habitats, i.e. seagrass Posidonia oceanica meadows, coralligenous formations, and marine caves, were determined through a systematic planning approach. Available information on the distribution of these habitats across the entire Mediterranean Sea was compiled to produce basin-scale distribution maps. Conservation targets for each habitat type were set according to European Union guidelines. Surrogates were used to estimate the spatial variation of opportunity cost for commercial, non-commercial fishing, and aquaculture. Marxan conservation planning software was used to evaluate the comparative utility of two planning scenarios: (a) a whole-basin scenario, referring to selection of priority areas across the whole Mediterranean Sea, and (b) an ecoregional scenario, in which priority areas were selected within eight predefined ecoregions. Although both scenarios required approximately the same total area to be protected in order to achieve conservation targets, the opportunity cost differed between them. The whole-basin scenario yielded a lower opportunity cost, but the Alboran Sea ecoregion was not represented and priority areas were predominantly located in the Ionian, Aegean, and Adriatic Seas. In comparison, the ecoregional scenario resulted in a higher representation of ecoregions and a more even distribution of priority areas, albeit with a higher opportunity cost. We suggest that planning at the ecoregional level ensures better representativeness of the selected conservation features and adequate protection of species, functional, and genetic diversity across the basin. While there are several initiatives that identify priority areas in the Mediterranean Sea, our approach is novel as it combines three issues: (a) it is based on the distribution of habitats and not species, which was rarely the case in previous efforts, (b) it considers spatial variability of cost throughout this

Parasites of freshwater fishes and the Great American Biotic Interchange: a bridge too far?

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Choudhury, A; García-Varela, M; Pérez-Ponce de León, G

2017-03-01

We examine the extent to which adult helminths of freshwater fishes have been part of the Great American Biotic Interchange (GABI), by integrating information in published studies and new data from Panama with fish biogeography and Earth history of Middle America. The review illustrates the following: (1) the helminth fauna south of the Trans-Mexican Volcanic Belt, and especially south of the Isthmus of Tehuantepec, shows strong Neotropical affinities; (2) host-parasite associations follow principles of the 'biogeographic core fauna' in which host-lineage specificity is pronounced; (3) phylogenetic analysis of the widespread freshwater trematode family Allocreadiidae reveals a complex history of host-shifting and co-diversification involving mainly cyprinodontiforms and characids; (4) allocreadiids, monogeneans and spiruridan nematodes of Middle American cyprinodontiforms may provide clues to the evolutionary history of their hosts; and (5) phylogenetic analyses of cryptogonimid trematodes may reveal whether or how cichlids interacted with marine or brackish-water environments during their colonization history. The review shows that 'interchange' is limited and asymmetrical, but simple narratives of northward isthmian dispersal will likely prove inadequate to explain the historical biogeography of many host-parasite associations in tropical Middle America, particularly those involving poeciliids. Finally, our study highlights the urgent need for targeted survey work across Middle America, focused sampling in river drainages of Colombia and Venezuela, and deeper strategic sampling in other parts of South America, in order to develop and test robust hypotheses about fish-parasite associations in Middle America.

Mammal occurrence and roadkill in two adjacent ecoregions (Atlantic Forest and Cerrado in south-western Brazil

Directory of Open Access Journals (Sweden)

Nilton C. Cáceres

2010-10-01

Full Text Available This paper examines the frequencies of mammal roadkill in two adjacent biogeographic ecoregions (Atlantic Forest and Cerrado of Brazil. Mammals were recorded during a seven-year period and over 3,900 km of roads, in order to obtain data for frequencies of species in habitats (sites and frequencies of species killed by cars on roads. Sites (n = 80 within ecoregions (Cerrado, n = 57; Atlantic Forest, n = 23 were searched for records of mammals. Species surveyed in the entire region totaled 33, belonging to nine orders and 16 families. In the Cerrado, 31 species were recorded in habitats; of these, 25 were found dead on roads. In the Atlantic Forest ecoregions, however, we found 21 species in habitats, 16 of which were also found dead on roads. There was no overall significant difference between ecoregions for frequencies of occurrence in habitats or for roadkills, but there were differences between individual species. Hence, anteaters were mostly recorded in the Cerrado ecoregion, whereas caviomorph rodents tended to be more frequent in the Atlantic Forest ecoregion (seen mainly by roadkills. The greater number of species (overall and threatened and the greater abundance of species records in the Cerrado suggest that this ecoregion has a greater biodiversity and is better conserved than the Atlantic Forest ecoregion, in the state of Mato Grosso do Sul, south-western Brazil.

Changes in Species Richness and Composition of Tiger Moths (Lepidoptera: Erebidae: Arctiinae) among Three Neotropical Ecoregions

Science.gov (United States)

Beccacece, Hernán Mario; Zeballos, Sebastián Rodolfo; Zapata, Adriana Inés

2016-01-01

Paraná, Yungas and Chaco Serrano ecoregions are among the most species-rich terrestrial habitats at higher latitude. However, the information for tiger moths, one of the most speciose groups of moths, is unknown in these ecoregions. In this study, we assess their species richness and composition in all three of these ecoregions. Also we investigated whether the species composition of tiger moths is influenced by climatic factors and altitude. Tiger moth species were obtained with samples from 71 sites using standardized protocols (21 sites were in Yungas, 19 in Paraná and 31 in Chaco Serrano). Rarefaction-extrapolation curves, non-parametric estimators for incidence and sample coverage indices were performed to assess species richness in the ecoregions studied. Non metric multidimensional scaling and adonis tests were performed to compare the species composition of tiger moths among ecoregions. Permutest analysis and Pearson correlation were used to evaluate the relationship among species composition and annual mean temperature, annual temperature range, annual precipitation, precipitation seasonality and altitude. Among ecoregions Paraná was the richest with 125 species, followed by Yungas with 63 species and Chaco Serrano with 24 species. Species composition differed among these ecoregions, although Yungas and Chaco Serrano were more similar than Paraná. Species composition was significantly influenced by climatic factors and altitude. This study showed that species richness and species composition of tiger moths differed among the three ecoregions assessed. Furthermore, not only climatic factors and altitude influence the species composition of tiger moths among ecoregions, but also climatic seasonality at higher latitude in Neotropical South America becomes an important factor. PMID:27681478

Changes in Species Richness and Composition of Tiger Moths (Lepidoptera: Erebidae: Arctiinae among Three Neotropical Ecoregions.

Directory of Open Access Journals (Sweden)

Hernán Mario Beccacece

Full Text Available Paraná, Yungas and Chaco Serrano ecoregions are among the most species-rich terrestrial habitats at higher latitude. However, the information for tiger moths, one of the most speciose groups of moths, is unknown in these ecoregions. In this study, we assess their species richness and composition in all three of these ecoregions. Also we investigated whether the species composition of tiger moths is influenced by climatic factors and altitude. Tiger moth species were obtained with samples from 71 sites using standardized protocols (21 sites were in Yungas, 19 in Paraná and 31 in Chaco Serrano. Rarefaction-extrapolation curves, non-parametric estimators for incidence and sample coverage indices were performed to assess species richness in the ecoregions studied. Non metric multidimensional scaling and adonis tests were performed to compare the species composition of tiger moths among ecoregions. Permutest analysis and Pearson correlation were used to evaluate the relationship among species composition and annual mean temperature, annual temperature range, annual precipitation, precipitation seasonality and altitude. Among ecoregions Paraná was the richest with 125 species, followed by Yungas with 63 species and Chaco Serrano with 24 species. Species composition differed among these ecoregions, although Yungas and Chaco Serrano were more similar than Paraná. Species composition was significantly influenced by climatic factors and altitude. This study showed that species richness and species composition of tiger moths differed among the three ecoregions assessed. Furthermore, not only climatic factors and altitude influence the species composition of tiger moths among ecoregions, but also climatic seasonality at higher latitude in Neotropical South America becomes an important factor.

Multi-site Management Plan Ecoregional Conservation for the Ouachita Ecoregion Arkansas and Oklahoma

Science.gov (United States)

2006-08-01

Poultry Disposal Pits. Ark. Water Res. Cen. fact sheet no. 2, n.d. Fausch , Kurt D., et al . Fish Communities as Indicators of Environmental...Degradation. Amer. Fish. Soc. Sym. 8, pp. 123-144; 1990. Ouachita Highlands Ecoregional Assessment – Appendix A 24 Fausch , Kurt D., et al . Regional...Interior Plateau of USEPA ( 2002 ). SOURCES References: DeSelm and Murdock 1993, DeSelm and Webb 1997, Nelson 1985, USFWS 1974, Webb et al . 1997 Last

RESEARCH: An Ecoregional Approach to the Economic Valuation of Land- and Water-Based Recreation in the United States

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Bhat; Bergstrom; Teasley; Bowker; Cordell

1998-01-01

/ This paper describes a framework for estimating the economic value of outdoor recreation across different ecoregions. Ten ecoregions in the continental United States were defined based on similarly functioning ecosystem characters. The individual travel cost method was employed to estimate recreation demand functions for activities such as motor boating and waterskiing, developed and primitive camping, coldwater fishing, sightseeing and pleasure driving, and big game hunting for each ecoregion. While our ecoregional approach differs conceptually from previous work, our results appear consistent with the previous travel cost method valuation studies.KEY WORDS: Recreation; Ecoregion; Travel cost method; Truncated Poisson model

Middle Rockies Ecoregion: Chapter 5 in Status and trends of land change in the Western United States--1973 to 2000

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Taylor, Janis L.

2012-01-01

The Middle Rockies Ecoregion—characterized by steep, high-elevation mountain ranges and intermountain valleys—is a disjunct ecoregion composed of three distinct geographic areas: the Greater Yellowstone area in northwest Wyoming, southwest Montana, and eastern Idaho; the Bighorn Mountains in north-central Wyoming and south-central Montana; and the Black Hills in western South Dakota and eastern Wyoming (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion covers approximately 90,160 km2 (34,881 mi2), and its three distinct geographic sections are bordered by several other ecoregions (fig. 1). The Yellowstone section abuts the Montana Valley and Foothill Prairies and the Northern Rockies Ecoregions to the north, the Snake River Basin and the Central Basin and Range Ecoregions to the west, and the Wyoming Basin Ecoregion to the south and east. The Bighorn Mountains section lies between the Wyoming Basin Ecoregion to the west and the Northwestern Great Plains Ecoregion to the east, and it abuts the Montana Valleys and Foothill Prairies Ecoregion to the north. The Black Hills section is entirely surrounded by the Northwestern Great Plains Ecoregion. The Continental Divide crosses the ecoregion from the southeast along the Wind River Range, through Yellowstone National Park, and west along the Montana-Idaho border. On both sides of the divide, topographic relief causes local climate variability, particularly the effects of aspect, exposure to prevailing wind, thermal inversions, and rain-shadow effects, that are reflected in the wide variety of flora and fauna within the ecoregion (Ricketts and others, 1999).

Changes of arthropod diversity across an altitudinal ecoregional zonation in Northwestern Argentina

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Andrea X. González-Reyes

2017-12-01

Full Text Available This study examined arthropod community patterns over an altitudinal ecoregional zonation that extended through three ecoregions (Yungas, Monte de Sierras y Bolsones, and Puna and two ecotones (Yungas-Monte and Prepuna of Northwestern Argentina (altitudinal range of 2,500 m, and evaluated the abiotic and biotic factors and the geographical distance that could influence them. Pitfall trap and suction samples were taken seasonally in 15 sampling sites (1,500–4,000 m a.s.l during one year. In addition to climatic variables, several soil and vegetation variables were measured in the field. Values obtained for species richness between ecoregions and ecotones and by sampling sites were compared statistically and by interpolation–extrapolation analysis based on individuals at the same sample coverage level. Effects of predictor variables and the similarity of arthropods were shown using non-metric multidimensional scaling, and the resulting groups were evaluated using a multi-response permutation procedure. Polynomial regression was used to evaluate the relationship between altitude with total species richness and those of hyperdiverse/abundant higher taxa and the latter taxa with each predictor variable. The species richness pattern displayed a decrease in species diversity as the elevation increased at the bottom wet part (Yungas of our altitudinal zonation until the Monte, and a unimodal pattern of diversity in the top dry part (Monte, Puna. Each ecoregion and ecotonal zone evidenced a particular species richness and assemblage of arthropods, but the latter ones displayed a high percentage of species shared with the adjacent ecoregions. The arthropod elevational pattern and the changes of the assemblages were explained by the environmental gradient (especially the climate in addition to a geographic gradient (the distance of decay of similarity, demonstrating that the species turnover is important to explain the beta diversity along the

Arizona/New Mexico Plateau Ecoregion: Chapter 26 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Ruhlman, Jana; Gass, Leila; Middleton, Barry

2012-01-01

Situated between ecoregions of distinctly different topographies and climates, the Arizona/New Mexico Plateau Ecoregion represents a large area of approximately 192,869 km2 (74,467 mi2) that stretches across northern Arizona, central and northwestern New Mexico, and parts of southwestern Colorado; in addition, a small part extends into southeastern Nevada (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). Forested, mountainous terrain borders the ecoregion on the northeast (Southern Rockies Ecoregion) and southwest (Arizona/New Mexico Mountains Ecoregion). Warmer and drier climates exist to the south (Chihuahuan Deserts Ecoregion) and west (Mojave Basin and Range Ecoregion). The semiarid grasslands of the western Great Plains are to the east (Southwestern Tablelands Ecoregion), and the tablelands of the Colorado Plateau in Utah and western Colorado lie to the north (Colorado Plateaus Ecoregion). The Arizona/New Mexico Plateau Ecoregion occupies a significant portion of the southern half of the Colorado Plateau.

Standard methods for sampling freshwater fishes: opportunities for international collaboration

OpenAIRE

Bonar, Scott A.; Mercado-Silva, Norman; Hubert, Wayne A.; Beard, T. Douglas; Dave, Göran; Kubečka, Jan; Graeb, Brian D.S.; Lester, Nigel P.; Porath, Mark; Winfield, Ian J.

2017-01-01

With publication of Standard Methods for Sampling North American Freshwater Fishes in 2009, the American Fisheries Society (AFS) recommended standard procedures for North America. To explore interest in standardizing at intercontinental scales, a symposium attended by international specialists in freshwater fish sampling was convened at the 145th Annual AFS Meeting in Portland, Oregon, in August 2015. Participants represented all continents except Australia and Antarctica and were employed by...

Extension of landscape-based population viability models to ecoregional scales for conservation planning

Science.gov (United States)

Thomas W. Bonnot; Frank R. III Thompson; Joshua Millspaugh

2011-01-01

Landscape-based population models are potentially valuable tools in facilitating conservation planning and actions at large scales. However, such models have rarely been applied at ecoregional scales. We extended landscape-based population models to ecoregional scales for three species of concern in the Central Hardwoods Bird Conservation Region and compared model...

Canadian Rockies Ecoregion: Chapter 4 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Taylor, Janis L.

2012-01-01

The Canadian Rockies Ecoregion covers approximately 18,494 km2 (7,141 mi2) in northwestern Montana (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The east side of the ecoregion is bordered by the Montana Valley and Foothill Prairies Ecoregion, which also forms a large part of the western border of the ecoregion. In addition, the Northern Rockies Ecoregion wraps around the ecoregion to the northwest and south (fig. 1). As the name implies, the Canadian Rocky Mountains are located mostly in Canada, straddling the border between Alberta and British Columbia. However, this ecoregion only includes the part of the northern Rocky Mountains that is in the United States. This ecoregion is characterized by steep, high-elevation mountain ranges similar to most of the rest of the Rocky Mountains. Compared to the Northern Rockies Ecoregion, however, the Canadian Rockies Ecoregion reaches higher elevations and contains a greater proportion of perennial snow and ice (Omernik, 1987) (fig. 2). Over the years, this section of the Rocky Mountains has garnered many different names, including “Crown of the Continent” by George Bird Grinnell (Waldt, 2008) and “Backbone of the World” by the Blackfeet (Pikuni) Nation. Throughout the ecoregion, montane, subalpine, and alpine ecosystems have distinct flora and fauna elevation zones. Glaciers, permanent snowfields, and seasonal snowpack are found at the highest elevations. Spring and summer runoff fills lakes and tarns that form the headwaters of numerous streams and rivers, including the Columbia and Missouri Rivers that flow west and east, respectively, from the Continental Divide.

Level IV Ecoregions of the Conterminous United States

Data.gov (United States)

U.S. Environmental Protection Agency — Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a...

Klamath Mountains Ecoregion: Chapter 13 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Sleeter, Benjamin M.; Calzia, James P.

2012-01-01

The Klamath Mountains Ecoregion covers approximately 47,791 km2 (18,452 mi2) of the Klamath and Siskiyou Mountains of northern California and southern Oregon (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is flanked by the Coast Range Ecoregion to the west, the Southern and Central California Chaparral and Oak Woodlands Ecoregion to the south, the Cascades and the Eastern Cascades Slopes and Foothills Ecoregions to the east, and the Willamette Valley Ecoregion to the north. The mild Mediterranean climate of the ecoregion is characterized by hot, dry summers and wet winters; the amount of winter moisture varies within the ecoregion, decreasing from west to east. The Klamath–Siskiyou Mountains region is widely recognized as an important biodiversity hotspot (Whittaker, 1960; Kruckeberg, 1984; Wagner, 1997; DellaSala and others, 1999), containing more than 3,500 plant species, more than 200 of which are endemic (Sawyer, 2007). A biological assessment by DellaSala and others (1999) ranked the Klamath–Siskiyou Mountains region as the fifth richest coniferous forest in terms of species diversity. In addition, the International Union for the Conservation of Nature considers the region an area of notable botanical importance (Wagner, 1997). Twenty-nine different species of conifers can be found in the Klamath Mountains Ecoregion (Sawyer, 1996).

Species discovery and diversity in Lobocriconema (Criconematidae: Nematoda) and related plant-parasitic nematodes from North American ecoregions.

Science.gov (United States)

Powers, T O; Bernard, E C; Harris, T; Higgins, R; Olson, M; Olson, S; Lodema, M; Matczyszyn, J; Mullin, P; Sutton, L; Powers, K S

2016-03-03

There are many nematode species that, following formal description, are seldom mentioned again in the scientific literature. Lobocriconema thornei and L. incrassatum are two such species, described from North American forests, respectively 37 and 49 years ago. In the course of a 3-year nematode biodiversity survey of North American ecoregions, specimens resembling Lobocriconema species appeared in soil samples from both grassland and forested sites. Using a combination of molecular and morphological analyses, together with a set of species delimitation approaches, we have expanded the known range of these species, added to the species descriptions, and discovered a related group of species that form a monophyletic group with the two described species. In this study, 148 specimens potentially belonging to the genus Lobocriconema were isolated from soil, individually measured, digitally imaged, and DNA barcoded using a 721 bp region of cytochrome oxidase subunit 1 (COI). One-third of the specimens were also analyzed using amplified DNA from the 3' region of the small subunit ribosomal RNA gene (18SrDNA) and the adjacent first internal transcribed spacer (ITS1). Eighteen mitochondrial haplotype groups, falling into four major clades, were identified by well-supported nodes in Bayesian and maximum likelihood trees and recognized as distinct lineages by species delimitation metrics. Discriminant function analysis of a set of morphological characters indicated that the major clades in the dataset possessed a strong morphological signal that decreased in comparisons of haplotype groups within clades. Evidence of biogeographic and phylogeographic patterns was apparent in the dataset. COI haplotype diversity was high in the southern Appalachian Mountains and Gulf Coast states and lessened in northern temperate forests. Lobocriconema distribution suggests the existence of phylogeographic patterns associated with recolonization of formerly glaciated regions by eastern

Conservation status of imperiled north American freshwater and diadromous fishes

Science.gov (United States)

Jelks, H.L.; Walsh, S.J.; Burkhead, N.M.; Contreras-Balderas, Salvador; Diaz-Pardo, E.; Hendrickson, D.A.; Lyons, J.; Mandrak, N.E.; McCormick, F.; Nelson, Joseph S.; Platania, Steven P.; Porter, B.A.; Renaud, C.B.; Schmitter-Soto, J. J.; Taylor, E.B.; Warren, M.L.

2008-01-01

This is the third compilation of imperiled (i.e., endangered, threatened, vulnerable) plus extinct freshwater and diadromous fishes of North America prepared by the American Fisheries Society's Endangered Species Committee. Since the last revision in 1989, imperilment of inland fishes has increased substantially. This list includes 700 extant taxa representing 133 genera and 36 families, a 92% increase over the 364 listed in 1989. The increase reflects the addition of distinct populations, previously non-imperiled fishes, and recently described or discovered taxa. Approximately 39% of described fish species of the continent are imperiled. There are 230 vulnerable, 190 threatened, and 280 endangered extant taxa, and 61 taxa presumed extinct or extirpated from nature. Of those that were imperiled in 1989, most (89%) are the same or worse in conservation status; only 6% have improved in status, and 5% were delisted for various reasons. Habitat degradation and nonindigenous species are the main threats to at-risk fishes, many of which are restricted to small ranges. Documenting the diversity and status of rare fishes is a critical step in identifying and implementing appropriate actions necessary for their protection and management.

Omernik's Level III Ecoregions Of The Conterminous United States

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U.S. Environmental Protection Agency — Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a...

Conservation priorities in the Apache Highlands ecoregion

Science.gov (United States)

Dale Turner; Rob Marshall; Carolyn A. F. Enquist; Anne Gondor; David F. Gori; Eduardo Lopez; Gonzalo Luna; Rafaela Paredes Aguilar; Chris Watts; Sabra Schwartz

2005-01-01

The Apache Highlands ecoregion incorporates the entire Madrean Archipelago/Sky Island region. We analyzed the current distribution of 223 target species and 26 terrestrial ecological systems there, and compared them with constraints on ecosystem integrity (e.g., road density) to determine the most efficient set of areas needed to maintain current biodiversity. The...

Arizona/New Mexico Mountains Ecoregion: Chapter 10 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Ruhlman, Jana; Gass, Leila; Middleton, Barry

2012-01-01

As the name suggests, the Arizona/New Mexico Mountains Ecoregion includes much of the mountainous regions of these two states, plus a very small part in the Guadalupe Mountains of northwestern Texas. Several isolated areas of higher terrain in Arizona and New Mexico are also included in the ecoregion, which occupies approximately 108,432 km2 (41,866 mi2) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is bounded on the south by the Sonoran Basin and Range, Madrean Archipelago, and Chihuahuan Deserts Ecoregions; to the north, the ecoregion is both bounded and surrounded by the Arizona/New Mexico Plateau Ecoregion (fig. 1). The ecoregion encompasses the largest contiguous ponderosa pine (Pinus ponderosa) forest in the United States (Strom and Fulé, 2007), which stretches from Williams, Arizona, along the Mogollon Rim, Arizona, into southwestern New Mexico, north and west of Silver City, New Mexico.

Madrean Archipelago Ecoregion: Chapter 28 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Ruhlman, Jana; Gass, Leila; Middleton, Barry

2012-01-01

The Madrean Archipelago Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997), also known as the “Madrean Sky Islands” or “Sky Islands,” covers an area of approximately 40,536 km2 (15,651 mi2) in southeastern Arizona and southwestern New Mexico (fig. 1). The ecoregion is bounded on the west by the Sonoran Basin and Range Ecoregion, on the east by the Chihuahuan Deserts Ecoregion, and on the north by the Arizona/New Mexico Mountains Ecoregion. This area of basin-and-range topography is one of the most biologically diverse in the world (Koprowski, 2005; Skroch, 2008). Although the mountains in the ecoregion bridge the Rocky Mountains to the north and the Sierra Madre Occidental in Mexico to the south (U.S. Environmental Protection Agency, 1997), the lower elevations act as a barrier to species dispersal. Nevertheless, the geographic convergence of these two major continental mountain ranges, as well as of the Chihuahuan Desert to the east and the Sonoran Desert to the west, forms the foundation for ecological interactions found nowhere else on Earth (Skroch, 2008).

Wasatch and Uinta Mountains Ecoregion: Chapter 9 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Brooks, Mark S.

2012-01-01

The Wasatch and Uinta Mountains Ecoregion covers approximately 44,176 km2 (17, 057 mi2) (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). With the exception of a small part of the ecoregion extending into southern Wyoming and southern Idaho, the vast majority of the ecoregion is located along the eastern mountain ranges of Utah. The ecoregion is situated between the Wyoming Basin and Colorado Plateaus Ecoregions to the east and south and the Central Basin and Range Ecoregion to the west; in addition, the Middle Rockies, Snake River Basin, and Northern Basin and Range Ecoregions are nearby to the north. Considered the western front of the Rocky Mountains, the two major mountain ranges that define the Wasatch and Uinta Mountains Ecoregion include the north-south-trending Wasatch Range and east-west- trending Uinta Mountains. Both mountain ranges have been altered by multiple mountain building and burial cycles since the Precambrian era 2.6 billion years ago, and they have been shaped by glacial processes as early as 1.6 million years ago. The terrain is defined by sharp ridgelines, glacial lakes, and narrow canyons, with elevations ranging from 1,829 m in the lower canyons to 4,123 m at Kings Peak, the highest point in Utah (Milligan, 2010).

A PROPOSED METHODOLOGY FOR ESTIMATING ECOREGIONAL VALUES FOR OUTDOOR RECREATION IN THE UNITED STATES

OpenAIRE

Bhat, Gajanan; Bergstrom, John C.; Bowker, James Michael; Cordell, H. Ken

1996-01-01

This paper provides a methodology for the estimation of recreational demand functions and values using an ecoregional approach. Ten ecoregions in the continental US were defined based on similarly functioning ecosystem characters. The individual travel cost method was employed to estimate the recreational demand functions for activities such as motorboating and waterskiing, developed and primative camping, coldwater fishing, sightseeing and pleasure driving, and big game hunting for each ecor...

An ecoregional approach to the economic valuation of land- and water-based recreation in the United States

Science.gov (United States)

Gajana Bhat; John Bergsrom; R. Jeff. Teasley

1998-01-01

This paper describes a framework for estimating the economic value of outdoor recreation across different ecoregions. Ten ecoregions in the continental United States were defined based on similarly functioning ecosystem characters. The individual travel cost method was employed to estimate recreation demand functions for activities such...

The evolution of body size in extant groups of North American freshwater fishes: speciation, size distributions, and Cope's rule.

Science.gov (United States)

Knouft, Jason H; Page, Lawrence M

2003-03-01

Change in body size within an evolutionary lineage over time has been under investigation since the synthesis of Cope's rule, which suggested that there is a tendency for mammals to evolve larger body size. Data from the fossil record have subsequently been examined for several other taxonomic groups to determine whether they also displayed an evolutionary increase in body size. However, we are not aware of any species-level study that has investigated the evolution of body size within an extant continental group. Data acquired from the fossil record and data derived from the evolutionary relationships of extant species are not similar, with each set exhibiting both strengths and weaknesses related to inferring evolutionary patterns. Consequently, expectation that general trends exhibited in the fossil record will correspond to patterns in extant groups is not necessarily warranted. Using phylogenetic relationships of extant species, we show that five of nine families of North American freshwater fishes exhibit an evolutionary trend of decreasing body size. These trends result from the basal position of large species and the more derived position of small species within families. Such trends may be caused by the invasion of small streams and subsequent isolation and speciation. This pattern, potentially influenced by size-biased dispersal rates and the high percentage of small streams in North America, suggests a scenario that could result in the generation of the size-frequency distribution of North American freshwater fishes.

Genetic calibration of species diversity among North America's freshwater fishes.

Science.gov (United States)

April, Julien; Mayden, Richard L; Hanner, Robert H; Bernatchez, Louis

2011-06-28

Freshwater ecosystems are being heavily exploited and degraded by human activities all over the world, including in North America, where fishes and fisheries are strongly affected. Despite centuries of taxonomic inquiry, problems inherent to species identification continue to hamper the conservation of North American freshwater fishes. Indeed, nearly 10% of species diversity is thought to remain undescribed. To provide an independent calibration of taxonomic uncertainty and to establish a more accessible molecular identification key for its application, we generated a standard reference library of mtDNA sequences (DNA barcodes) derived from expert-identified museum specimens for 752 North American freshwater fish species. This study demonstrates that 90% of known species can be delineated using barcodes. Moreover, it reveals numerous genetic discontinuities indicative of independently evolving lineages within described species, which points to the presence of morphologically cryptic diversity. From the 752 species analyzed, our survey flagged 138 named species that represent as many as 347 candidate species, which suggests a 28% increase in species diversity. In contrast, several species of parasitic and nonparasitic lampreys lack such discontinuity and may represent alternative life history strategies within single species. Therefore, it appears that the current North American freshwater fish taxonomy at the species level significantly conceals diversity in some groups, although artificially creating diversity in others. In addition to providing an easily accessible digital identification system, this study identifies 151 fish species for which taxonomic revision is required.

Conservation status of the freshwater mussels of the United States and Canada

Science.gov (United States)

James D. Williams; Melvin L. Warren; Kevin S. Cummings; John L. Harris; Richard J. Neves

1992-01-01

The American Fisheries Society (AFS) herein provides a list of all native freshwater mussels (families Margaritiferidae and Unionidae) in the United States and Canada. This report also provides state and provincial distributions; a comprehensive review of the conservation status of all taxa; and references on biology, conservation, and distribution of freshwater...

Peatlands of the Peruvian Puna ecoregion: types, characteristics and disturbance

Directory of Open Access Journals (Sweden)

F. Salvador

2014-05-01

Full Text Available Peatlands represent one of the most important water resources in the Puna grassland ecoregion, but this fact is not yet widely recognised. Puna peatlands also provide key environmental services such as increasing the regional biodiversity of the Andean Altiplano plateau and contributing to the wellbeing of high-altitude human populations by providing grazing land and cooking fuel. We conducted a study in the Peruvian Puna ecoregion to describe the current condition of peatlands in terms of their vegetation, physical and chemical characteristics and disturbance status. Our results suggest that peat thickness, organic matter and degree of humification are good indicators for identifying peatlands in the Puna ecoregion. In general, the peatland sites that we sampled were dominated by mixtures of cushion and acaulescent rosette forming plants such as Distichia muscoides Nees & Meyen and Plantago tubulosa Decne. These Distichia and Plantago peatland sites were characterised by a mean surface water pH of 6.3, corrected electrical conductivity (K corr. in the range 300–1814 μS cm-1 and presented the following mean exchangeable cation values: Ca2+ 48 mg L-1, Mg2+ 9.6 mg L-1, Na+ 8.2 mg L-1 and K+ 2.1 mg L-1. The most common causes of disturbance we encountered were grazing, peat extraction and roads. Disturbance was most severe in mining sites, where peatlands are especially vulnerable because they are not under legal protection.

Estimating carbon sequestration in the piedmont ecoregion of the United States from 1971 to 2010

Science.gov (United States)

Liu, Jinxun; Sleeter, Benjamin M.; Zhu, Zhiliang; Heath, Linda S.; Tan, Zhengxi; Wilson, Tamara; Sherba, Jason T.; Zhou, Decheng

2016-01-01

Background: Human activities have diverse and profound impacts on ecosystem carbon cycles. The Piedmont ecoregion in the eastern United States has undergone significant land use and land cover change in the past few decades. The purpose of this study was to use newly available land use and land cover change data to quantify carbon changes within the ecoregion. Land use and land cover change data (60-m spatial resolution) derived from sequential remotely sensed Landsat imagery were used to generate 960-m resolution land cover change maps for the Piedmont ecoregion. These maps were used in the Integrated Biosphere Simulator (IBIS) to simulate ecosystem carbon stock and flux changes from 1971 to 2010. Results: Results show that land use change, especially urbanization and forest harvest had significant impacts on carbon sources and sinks. From 1971 to 2010, forest ecosystems sequestered 0.25 Mg C ha−1 yr−1, while agricultural ecosystems sequestered 0.03 Mg C ha−1 yr−1. The total ecosystem C stock increased from 2271 Tg C in 1971 to 2402 Tg C in 2010, with an annual average increase of 3.3 Tg C yr−1. Conclusions: Terrestrial lands in the Piedmont ecoregion were estimated to be weak net carbon sink during the study period. The major factors contributing to the carbon sink were forest growth and afforestation; the major factors contributing to terrestrial emissions were human induced land cover change, especially urbanization and forest harvest. An additional amount of carbon continues to be stored in harvested wood products. If this pool were included the carbon sink would be stronger. Keywords: Land-use change, Carbon change, Piedmont ecoregion, IBIS model

Southern Great Plains Rapid Ecoregional assessment—Volume I. Ecological communities

Science.gov (United States)

Reese, Gordon C.; Burris, Lucy; Carr, Natasha B.; Leinwand, Ian I.F.; Melcher, Cynthia P.

2017-10-19

The Southern Great Plains Rapid Ecoregional Assessment was conducted in partnership with the Bureau of Land Management (BLM) and the Great Plains Landscape Conservation Cooperative. The overall goal of the Rapid Ecoregional Assessments (REAs) is to compile and synthesize regional datasets to facilitate evaluation of the cumulative effects of change agents on priority ecological communities and species. In particular, the REAs identify and map the distribution of communities and wildlife habitats at broad spatial extents and provide assessments of ecological conditions. The REAs also identify where and to what degree ecological resources are currently at risk from change agents, such as development, fire, invasive species, and climate change. The REAs can help managers identify and prioritize potential areas for conservation or restoration, assess cumulative effects as required by the National Environmental Policy Act, and inform landscape-level planning and management decisions for multiple uses of public lands.Management questions form the basis for the REA framework and were developed in conjunction with the BLM and other stakeholders. Conservation elements are communities and species that are of regional management concern. Core management questions relate to the key ecological attributes and change agents associated with each conservation element. Integrated management questions synthesize the results of the primary core management questions into overall landscape-level ranks for each conservation element.The ecological communities evaluated as conservation elements are shortgrass, mixed-grass, and sand prairies; all grasslands; riparian and nonplaya wetlands; playa wetlands and saline lakes; and prairie streams and rivers. Species and species assemblages evaluated are the freshwater mussel assemblage, Arkansas River shiner (Notropis girardi), ferruginous hawk (Buteo regalis), lesser prairie chicken (Tympanuchus pallidicinctus), snowy plover (Charadrius

Genetic calibration of species diversity among North America's freshwater fishes

OpenAIRE

April, Julien; Mayden, Richard L.; Hanner, Robert H.; Bernatchez, Louis

2011-01-01

Freshwater ecosystems are being heavily exploited and degraded by human activities all over the world, including in North America, where fishes and fisheries are strongly affected. Despite centuries of taxonomic inquiry, problems inherent to species identification continue to hamper the conservation of North American freshwater fishes. Indeed, nearly 10% of species diversity is thought to remain undescribed. To provide an independent calibration of taxonomic uncertainty and to establish a mor...

Freshwater Megafauna: Flagships for Freshwater Biodiversity under Threat.

Science.gov (United States)

Carrizo, Savrina F; Jähnig, Sonja C; Bremerich, Vanessa; Freyhof, Jörg; Harrison, Ian; He, Fengzhi; Langhans, Simone D; Tockner, Klement; Zarfl, Christiane; Darwall, William

2017-10-01

Freshwater biodiversity is highly threatened and is decreasing more rapidly than its terrestrial or marine counterparts; however, freshwaters receive less attention and conservation investment than other ecosystems do. The diverse group of freshwater megafauna, including iconic species such as sturgeons, river dolphins, and turtles, could, if promoted, provide a valuable tool to raise awareness and funding for conservation. We found that freshwater megafauna inhabit every continent except Antarctica, with South America, Central Africa, and South and Southeast Asia being particularly species rich. Freshwater megafauna co-occur with up to 93% of mapped overall freshwater biodiversity. Fifty-eight percent of the 132 megafauna species included in the study are threatened, with 84% of their collective range falling outside of protected areas. Of all threatened freshwater species, 83% are found within the megafauna range, revealing the megafauna's capacity as flagship and umbrella species for fostering freshwater conservation.

The decline of North American freshwater fishes

Science.gov (United States)

Walsh, Stephen J.; Jelks, Howard L.; Burkhead, Noel M.

2009-01-01

North America has a broad array of freshwater ecosystems because of the continent's complex geography and geological history. Within a multitude of habitats—that include streams, large rivers, natural lakes, springs, and wetlands—rich assemblages of fishes reside, representing diverse taxonomic groups with unique ecological requirements. They face an unprecedented conservation crisis.1 In the last few decades, the proportion of inland fishes of North America, which are considered imperiled or extinct, increased from 20 to 40%.2 Although extinctions have occurred, many species and populations are declining in range size and abundance. The fish biota of the continent as a whole remains diverse; however, we can take action to stem any further declines.

Documentation of Significant Losses in Cornus florida L. Populations throughout the Appalachian Ecoregion

Directory of Open Access Journals (Sweden)

Christopher M. Oswalt

2010-01-01

Full Text Available Over the last three decades the fungus Discula destructiva Redlin has severely impacted Cornus florida L. (flowering dogwood—hereafter “dogwood” populations throughout its range. This study estimates historical and current dogwood populations (number of trees across the Appalachian ecoregion. Objectives were to (1 quantify current dogwood populations in the Appalachian ecoregion, (2 quantify change over time in dogwood populations, and (3 identify trends in dogwood population shifts. Data from the USDA Forest Service Forest Inventory and Analysis (FIA database were compiled from 41 FIA units in 13 states for county-level estimates of the total number of all live dogwood trees on timberland within the Appalachian ecoregion. Analysis of covariance, comparing historical and current county-level dogwood population estimates with average change in forest density as the covariate, was used to identify significant changes within FIA units. Losses ranging from 25 to 100 percent of the sample population (<.05 were observed in 33 of the 41 (80 percent sampled FIA units. These results indicate that an important component of the eastern deciduous forest has experienced serious losses throughout the Appalachians and support localized empirical results and landscape-scale anecdotal evidence.

A new cryptic species of South American freshwater pufferfish of the genus Colomesus (Tetraodontidae, based on both morphology and DNA data.

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Cesar R L Amaral

Full Text Available The Tetraodontidae are an Acantomorpha fish family with circumglobal distribution composed of 189 species grouped in 19 genera, occurring in seas, estuaries, and rivers between the tropical and temperate regions. Of these, the genus Colomesus is confined to South America, with what have been up to now considered only two species. C. asellus is spread over the entire Amazon, Tocantins-Araguaia drainages, and coastal environments from the Amazon mouth to Venezuela, and is the only freshwater puffers on that continent. C. psittacus is found in coastal marine and brackish water environments from Cuba to the northern coast of South America as far south as to Sergipe in Brazil. In the present contribution we used morphological data along with molecular systematics techniques to investigate the phylogeny and phylogeography of the freshwater pufferfishes of the genus Colomesus. The molecular part is based on a cytochrome C oxidase subunit I dataset constructed from both previously published and newly determined sequences, obtained from specimens collected from three distinct localities in South America. Our results from both molecular and morphological approaches enable us to identify and describe a new Colomesus species from the Tocantins River. We also discuss aspects of the historical biogeography and phylogeography of the South American freshwater pufferfishes, suggesting that it could be more recent than previously expected.

Information to help reduce environmental impacts from freshwater oil spills

International Nuclear Information System (INIS)

Fritz, D.E.; Steen, A.E.

1995-01-01

The American Petroleum Institute (API) has been working since 1990 to provide information to help the response community minimize the impact of spills to pared jointly with the US inland freshwater. Projects have included a manual, pre National Oceanic and Atmospheric Administration (NOAA), to give guidance on the cleanup techniques that will minimize environmental impacts on spills in freshwater habitats. Nearing completion are a literature review and annotated bibliography of the environmental and human health effects of oil spilled in freshwater habitats. The use of chemical treating agents for freshwater spill applications is being studied with input from other industry and government groups. A project has begun, with funding from API, the Louisiana Applied Oil Spill Research and Development Program, NOAA, the Marine Spill Response Corporation (MSRC), and the US Department of Energy, to evaluate in situ burning of oil spilled in marshes

Ecoregion prioritization suggests an armoury not a silver bullet for conservation planning.

Directory of Open Access Journals (Sweden)

Stephan M Funk

Full Text Available In the face of accelerating species extinctions, map-based prioritization systems are increasingly useful to decide where to pursue conservation action most effectively. However, a number of seemingly inconsistent schemes have emerged, mostly focussing on endemism. Here we use global vertebrate distributions in terrestrial ecoregions to evaluate how continuous and categorical ranking schemes target and accumulate endangered taxa within the IUCN Red List, Alliance for Zero Extinction (AZE, and EDGE of Existence programme. We employed total, endemic and threatened species richness and an estimator for richness-adjusted endemism as metrics in continuous prioritization, and WWF's Global200 and Conservation International's (CI Hotspots in categorical prioritization. Our results demonstrate that all metrics target endangerment more efficiently than by chance, but each selects unique sets of top-ranking ecoregions, which overlap only partially, and include different sets of threatened species. Using the top 100 ecoregions as defined by continuous prioritization metrics, we develop an inclusive map for global vertebrate conservation that incorporates important areas for endemism, richness, and threat. Finally, we assess human footprint and protection levels within these areas to reveal that endemism sites are more impacted but have more protection, in contrast to high richness and threat ones. Given such contrasts, major efforts to protect global biodiversity must involve complementary conservation approaches in areas of unique species as well as those with highest diversity and threat.

STUDY ON THE SUGAR-ACID RATIO AND RELEVANT METABOLIZING ENZYME ACTIVITIES IN NAVEL ORANGE FRUITS FROM DIFFERENT ECO-REGIONS

Directory of Open Access Journals (Sweden)

GONG RONGGAO

2015-12-01

Full Text Available ABSTRACT The flavor quality of citrus fruits is largely determined by the sugar-acid ratio, but it remains uncertain how sugar- and/or acid-metabolizing enzymes regulate the sugar-acid ratio of navel oranges and further affect the fruit quality. In the present study, Robertson navel oranges (Citrus sinesis Osb. were collected from six representative habitats in three eco-regions of Sichuan, China. The changes in the sugar-acid ratio and the activities of sucrose phosphate synthase (SPS, sucrose synthase (SS, cytosolic cio-aconitase (ACO, and isocitrate dehydrogenase (IDH were examined in navel oranges during fruit development. The results indicated that the sugar-acid ratio of fruits in different eco-regions changed significantly from 150 days after full bloom. The SPS and cytosolic ACO fruit activities had minor changes among different ecoregions throughout the experimental periods, whereas the activities of SS and IDH changed significantly in fruits among three eco-regions. Furthermore, the sugar-acid ratio and the activities of SS in the synthetic direction and IDH were the highest in south subtropics and the lowest in north mid-subtropics, probably due to the effects of climate conditions and/or other relevant eco-factors. It demonstrated that SS in the synthetic direction and IDH were of greater importance in regulating the sugar-acid ratio of navel oranges in different eco-regions, which provided new insights into the factors that determine the flavor quality of navel oranges and valuable data for guiding relevant agricultural practices.

Effects of harvest, fire, and pest/pathogen disturbances on the West Cascades ecoregion carbon balance.

Science.gov (United States)

Turner, David P; Ritts, William D; Kennedy, Robert E; Gray, Andrew N; Yang, Zhiqiang

2015-12-01

Disturbance is a key influence on forest carbon dynamics, but the complexity of spatial and temporal patterns in forest disturbance makes it difficult to quantify their impacts on carbon flux over broad spatial domains. Here we used a time series of Landsat remote sensing images and a climate-driven carbon cycle process model to evaluate carbon fluxes at the ecoregion scale in western Oregon. Thirteen percent of total forest area in the West Cascades ecoregion was disturbed during the reference interval (1991-2010). The disturbance regime was dominated by harvesting (59 % of all area disturbed), with lower levels of fire (23 %), and pest/pathogen mortality (18 %). Ecoregion total Net Ecosystem Production was positive (a carbon sink) in all years, with greater carbon uptake in relatively cool years. Localized carbon source areas were associated with recent harvests and fire. Net Ecosystem Exchange (including direct fire emissions) showed greater interannual variation and became negative (a source) in the highest fire years. Net Ecosystem Carbon Balance (i.e. change in carbon stocks) was more positive on public that private forestland, because of a lower disturbance rate, and more positive in the decade of the 1990s than in the warmer and drier 2000s because of lower net ecosystem production and higher direct fire emissions in the 2000s. Despite recurrent disturbances, the West Cascades ecoregion has maintained a positive carbon balance in recent decades. The high degree of spatial and temporal resolution in these simulations permits improved attribution of regional carbon sources and sinks.

Ecoregions and ecodistricts: Ecological regionalizations for the Netherlands' environmental policy

Science.gov (United States)

Klijn, Frans; de Waal, Rein W.; Oude Voshaar, Jan H.

1995-11-01

For communicating data on the state of the environment to policy makers, various integrative frameworks are used, including regional integration. For this kind of integration we have developed two related ecological regionalizations, ecoregions and ecodistricts, which are two levels in a series of classifications for hierarchically nested ecosystems at different spatial scale levels. We explain the compilation of the maps from existing geographical data, demonstrating the relatively holistic, a priori integrated approach. The resulting maps are submitted to discriminant analysis to test the consistancy of the use of mapping characteristics, using data on individual abiotic ecosystem components from a national database on a 1-km2 grid. This reveals that the spatial patterns of soil, groundwater, and geomorphology correspond with the ecoregion and ecodistrict maps. Differences between the original maps and maps formed by automatically reclassifying 1-km2 cells with these discriminant components are found to be few. These differences are discussed against the background of the principal dilemma between deductive, a priori integrated, and inductive, a posteriori, classification.

A case for redefining the boundaries of the Mesoamerican Reef Ecoregion

Science.gov (United States)

Chollett, Iliana; Garavelli, Lysel; Holstein, Daniel; Cherubin, Laurent; Fulton, Stuart; Box, Stephen J.

2017-12-01

The Mesoamerican Reef (MAR) is an interconnected system that supports the local economies of four countries through the provision of seafood and tourism. Considerable financial, research and management effort has been invested in this priority ecoregion, whose boundaries were defined more than 18 yr ago based on best available data on oceanographic patterns, reef and watershed distribution. The long-term persistence of the MAR depends, however, on ensuring that all of its constituent parts are appropriately managed, and the current boundaries may not respond to this need. Here we assess the suitability of the current boundaries of the MAR using information on physical environments and larval connectivity of three key species. Our research indicates the boundaries of the ecoregion require an adjustment, as the exclusion of key areas in eastern Honduras might jeopardize the persistence of the entire network of connected reefs, and areas in northern Yucatan belong to a different environmental regime and may require different management strategies.

Estimating carbon sequestration in the piedmont ecoregion of the United States from 1971 to 2010

Directory of Open Access Journals (Sweden)

Jinxun Liu

2016-06-01

Full Text Available Abstract Background Human activities have diverse and profound impacts on ecosystem carbon cycles. The Piedmont ecoregion in the eastern United States has undergone significant land use and land cover change in the past few decades. The purpose of this study was to use newly available land use and land cover change data to quantify carbon changes within the ecoregion. Land use and land cover change data (60-m spatial resolution derived from sequential remotely sensed Landsat imagery were used to generate 960-m resolution land cover change maps for the Piedmont ecoregion. These maps were used in the Integrated Biosphere Simulator (IBIS to simulate ecosystem carbon stock and flux changes from 1971 to 2010. Results Results show that land use change, especially urbanization and forest harvest had significant impacts on carbon sources and sinks. From 1971 to 2010, forest ecosystems sequestered 0.25 Mg C ha−1 yr−1, while agricultural ecosystems sequestered 0.03 Mg C ha−1 yr−1. The total ecosystem C stock increased from 2271 Tg C in 1971 to 2402 Tg C in 2010, with an annual average increase of 3.3 Tg C yr−1. Conclusions Terrestrial lands in the Piedmont ecoregion were estimated to be weak net carbon sink during the study period. The major factors contributing to the carbon sink were forest growth and afforestation; the major factors contributing to terrestrial emissions were human induced land cover change, especially urbanization and forest harvest. An additional amount of carbon continues to be stored in harvested wood products. If this pool were included the carbon sink would be stronger.

Widespread Increases in Iron Concentration in European and North American Freshwaters

Czech Academy of Sciences Publication Activity Database

Björnerås, C.; Weyhenmeyer, G. A.; Evans, C. D.; Gessner, M. O.; Grossart, H. P.; Kangur, K.; Kokorite, I.; Kortelainen, P.; Laudon, H.; Lehtoranta, J.; Lottig, N.; Monteith, D. T.; Nõges, P.; Nõges, T.; Oulehle, Filip; Riise, G.; Rusak, J. A.; Räike, A.; Sire, J.; Sterling, S.; Kritzberg, E. S.

2017-01-01

Roč. 31, č. 10 (2017), s. 1488-1500 ISSN 0886-6236 R&D Projects: GA ČR(CZ) GA15-08124S Institutional support: RVO:86652079 Keywords : browning * climate change * freshwaters * iron * trends Subject RIV: EH - Ecology , Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.655, year: 2016

Widespread Increases in Iron Concentration in European and North American Freshwaters

Czech Academy of Sciences Publication Activity Database

Björnerås, C.; Weyhenmeyer, G. A.; Evans, C. D.; Gessner, M. O.; Grossart, H. P.; Kangur, K.; Kokorite, I.; Kortelainen, P.; Laudon, H.; Lehtoranta, J.; Lottig, N.; Monteith, D. T.; Nõges, P.; Nõges, T.; Oulehle, Filip; Riise, G.; Rusak, J. A.; Räike, A.; Sire, J.; Sterling, S.; Kritzberg, E. S.

2017-01-01

Roč. 31, č. 10 (2017), s. 1488-1500 ISSN 0886-6236 R&D Projects: GA ČR(CZ) GA15-08124S Institutional support: RVO:86652079 Keywords : browning * climate change * freshwaters * iron * trends Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.655, year: 2016

Parallel k-Means Clustering for Quantitative Ecoregion Delineation Using Large Data Sets

Science.gov (United States)

Jitendra Kumar; Richard T. Mills; Forrest M Hoffman; William W Hargrove

2011-01-01

Identification of geographic ecoregions has long been of interest to environmental scientists and ecologists for identifying regions of similar ecological and environmental conditions. Such classifications are important for predicting suitable species ranges, for stratification of ecological samples, and to help prioritize habitat preservation and remediation efforts....

Delimiting tropical mountain ecoregions for conservation

DEFF Research Database (Denmark)

Platts, Philip J.; Burgess, Neil David; Gereau, Roy E.

2011-01-01

Ecological regions aggregate habitats with similar biophysical characteristics within well-defined boundaries, providing spatially consistent platforms for monitoring, managing and forecasting the health of interrelated ecosystems. A major obstacle to the implementation of this approach is imprec......Ecological regions aggregate habitats with similar biophysical characteristics within well-defined boundaries, providing spatially consistent platforms for monitoring, managing and forecasting the health of interrelated ecosystems. A major obstacle to the implementation of this approach...... boundaries. LandScan and census data show population density inside the ecoregion to be higher than in rural lowlands, and lowland settlement to be most probable within 30 km. This definition should help to align landscape scale conservation strategies in the Eastern Arc and promote new research in areas...

Relative invasion risk for plankton across marine and freshwater systems: examining efficacy of proposed international ballast water discharge standards.

Directory of Open Access Journals (Sweden)

Oscar Casas-Monroy

Full Text Available Understanding the implications of different management strategies is necessary to identify best conservation trajectories for ecosystems exposed to anthropogenic stressors. For example, science-based risk assessments at large scales are needed to understand efficacy of different vector management approaches aimed at preventing biological invasions associated with commercial shipping. We conducted a landscape-scale analysis to examine the relative invasion risk of ballast water discharges among different shipping pathways (e.g., Transoceanic, Coastal or Domestic, ecosystems (e.g., freshwater, brackish and marine, and timescales (annual and per discharge event under current and future management regimes. The arrival and survival potential of nonindigenous species (NIS was estimated based on directional shipping networks and their associated propagule pressure, environmental similarity between donor-recipient ecosystems (based on salinity and temperature, and effects of current and future management strategies (i.e., ballast water exchange and treatment to meet proposed international biological discharge standards. Our findings show that current requirements for ballast water exchange effectively reduce invasion risk to freshwater ecosystems but are less protective of marine ecosystems because of greater environmental mismatch between source (oceanic and recipient (freshwater ecoregions. Future requirements for ballast water treatment are expected to reduce risk of zooplankton NIS introductions across ecosystem types but are expected to be less effective in reducing risk of phytoplankton NIS. This large-scale risk assessment across heterogeneous ecosystems represents a major step towards understanding the likelihood of invasion in relation to shipping networks, the relative efficacy of different invasion management regimes and seizing opportunities to reduce the ecological and economic implications of biological invasions.

Willamette Valley Ecoregion: Chapter 3 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Wilson, Tamara S.; Sorenson, Daniel G.

2012-01-01

The Willamette Valley Ecoregion (as defined by Omernik, 1987; U.S. Environmental Protection Agency, 1997) covers approximately 14,458 km² (5,582 mi2), making it one of the smallest ecoregions in the conterminous United States. The long, alluvial Willamette Valley, which stretches north to south more than 193 km and ranges from 32 to 64 km wide, is nestled between the sedimentary and metamorphic Coast Ranges (Coast Range Ecoregion) to the west and the basaltic Cascade Range (Cascades Ecoregion) to the east (fig. 1). The Lewis and Columbia Rivers converge at the ecoregion’s northern boundary in Washington state; however, the majority of the ecoregion falls within northwestern Oregon. Interstate 5 runs the length of the valley to its southern boundary with the Klamath Mountains Ecoregion. Topography here is relatively flat, with elevations ranging from sea level to 122 m. This even terrain, coupled with mild, wet winters, warm, dry summers, and nutrient-rich soil, makes the Willamette Valley the most important agricultural region in Oregon. Population centers are concentrated along the valley floor. According to estimates from the Oregon Department of Fish and Wildlife (2006), over 2.3 million people lived in Willamette Valley in 2000. Portland, Oregon, is the largest city, with 529,121 residents (U.S. Census Bureau, 2000). Other sizable cities include Eugene, Oregon; Salem (Oregon’s state capital); and Vancouver, Washington. Despite the large urban areas dotting the length of the Willamette Valley Ecoregion, agriculture and forestry products are its economic foundation (figs. 2,3). The valley is a major producer of grass seed, ornamental plants, fruits, nuts, vegetables, and grains, as well as poultry, beef, and dairy products. The forestry and logging industries also are primary employers of the valley’s rural residents (Rooney, 2008). These activities have affected the watershed significantly, with forestry and agricultural runoff contributing to river

Study on polychlorobiphenyl serum levels in French consumers of freshwater fish

International Nuclear Information System (INIS)

Desvignes, Virginie; Volatier, Jean-Luc; Bels, Frédéric de; Zeghnoun, Abdelkrim; Favrot, Marie-Christine; Marchand, Philippe; Le Bizec, Bruno; Rivière, Gilles; Leblanc, Jean-Charles; Merlo, Mathilde

2015-01-01

Introduction: Polychlorobiphenyls (PCBs) are persistent pollutants that are widespread in the environment and in foodstuffs, particularly in freshwater fish, which frequently exceed the maximum levels set by European regulations. Objectives: First, we describe the consumption of freshwater fish and serum PCB levels in French anglers, a population expected to have the highest level of dietary PCB exposure. Second, we investigated whether there is a statistical relationship between serum PCB levels and the angler consumption of freshwater fish with high PCB bioaccumulation potential (PCB-BP + freshwater fish) in order to make recommendations with regard to safe consumption of freshwater fish. Methods: We conducted a survey of anglers from six sites with contrasting PCB contamination levels. The survey included a food consumption frequency questionnaire and blood samples were taken to assess serum PCB levels. We used a regression model to determine the main factors contributing to serum PCB levels. Results: Consumption of PCB-BP + freshwater fish was relatively infrequent. Serum PCB levels of the study population and of women of childbearing age were in the same range as those observed in the French population and in neighbouring European countries, but higher than in the North American population. The two factors with the highest positive association with serum PCB levels were age (R 2 = 61%) and the consumption of PCB-BP + freshwater fish (R 2 = 2%). Using the regression model, we calculated, for several scenarios depending on the age and gender of the population, the maximum annual frequencies for PCB-BP + freshwater fish consumption that do not exceed the critical body burden threshold. Conclusion: Following the results of this study, the French agency for food, environmental and occupational health and safety (ANSES) issued an opinion and recommended some specific maximum freshwater fish consumption frequencies to protect the French general population

Study on polychlorobiphenyl serum levels in French consumers of freshwater fish

Energy Technology Data Exchange (ETDEWEB)

Desvignes, Virginie, E-mail: virginie.desvignes@anses.fr [Risk Assessment Department, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), 27–31, avenue du Général Leclerc, Maisons-Alfort, F-94701 (France); Volatier, Jean-Luc [Risk Assessment Department, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), 27–31, avenue du Général Leclerc, Maisons-Alfort, F-94701 (France); Bels, Frédéric de [Division for Public Health and Care, French National Cancer Institute (INCa), 52, avenue André Morizet, Boulogne Billancourt Cedex, F-92513 (France); Zeghnoun, Abdelkrim [Department of Environmental Health, French Institute for Public Health Surveillance (InVS), 12, rue du Val d' Osne, Saint-Maurice, F-94415 (France); Favrot, Marie-Christine [Ministry of Health, 14, avenue Duquesne, Paris, F-75350 (France); Marchand, Philippe; Le Bizec, Bruno [LUNAM Université, Oniris, Laboratoire d' Etude des Résidus et Contaminants dans les Aliments (LABERCA), USC INRA 1329, Nantes, F-44307 (France); Rivière, Gilles; Leblanc, Jean-Charles; Merlo, Mathilde [Risk Assessment Department, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), 27–31, avenue du Général Leclerc, Maisons-Alfort, F-94701 (France)

2015-02-01

Introduction: Polychlorobiphenyls (PCBs) are persistent pollutants that are widespread in the environment and in foodstuffs, particularly in freshwater fish, which frequently exceed the maximum levels set by European regulations. Objectives: First, we describe the consumption of freshwater fish and serum PCB levels in French anglers, a population expected to have the highest level of dietary PCB exposure. Second, we investigated whether there is a statistical relationship between serum PCB levels and the angler consumption of freshwater fish with high PCB bioaccumulation potential (PCB-BP{sup +} freshwater fish) in order to make recommendations with regard to safe consumption of freshwater fish. Methods: We conducted a survey of anglers from six sites with contrasting PCB contamination levels. The survey included a food consumption frequency questionnaire and blood samples were taken to assess serum PCB levels. We used a regression model to determine the main factors contributing to serum PCB levels. Results: Consumption of PCB-BP{sup +} freshwater fish was relatively infrequent. Serum PCB levels of the study population and of women of childbearing age were in the same range as those observed in the French population and in neighbouring European countries, but higher than in the North American population. The two factors with the highest positive association with serum PCB levels were age (R{sup 2} = 61%) and the consumption of PCB-BP{sup +} freshwater fish (R{sup 2} = 2%). Using the regression model, we calculated, for several scenarios depending on the age and gender of the population, the maximum annual frequencies for PCB-BP{sup +} freshwater fish consumption that do not exceed the critical body burden threshold. Conclusion: Following the results of this study, the French agency for food, environmental and occupational health and safety (ANSES) issued an opinion and recommended some specific maximum freshwater fish consumption frequencies to protect the French

A fine structure genetic analysis evaluating ecoregional adaptability of a Bos taurus breed (Hereford)

Science.gov (United States)

Ecoregional differences contribute to genetic environmental interactions and impact animal performance. These differences may become more important under climate change scenarios. Utilizing genetic diversity within a species to address such problems has not been fully explored. In this study Herefor...

Tropical Freshwater Biology

African Journals Online (AJOL)

Tropical Freshwater Biology promotes the publication of scientific contributions in the field of freshwater biology in the tropical and subtropical regions of the world. One issue is published annually but this number may be increased. Original research papers and short communications on any aspect of tropical freshwater ...

Development of index of biotic integrity expectations for the ecoregions of Indiana. I. Central corn belt plain

International Nuclear Information System (INIS)

1991-11-01

The Clean Water Act Amendments of 1987 mandate the development of biological criteria for evaluating the nation's surface waters. The requirements of Section 304(a) was implemented in Indiana to determine water resource degradation. A total of 197 headwater and wading stream sites were sampled in the Central Corn Belt Plain ecoregion in order to develop and calibrate an Index of Biotic Integrity for use in Indiana. Based on inherent variance within the ecoregion, sub-basins were established based on the concept of natural areas as recognized by Homoya et al. (1985). Site specific data; locality information; and species specific scoring criteria for tolerance classification, trophic guilds, and reproductive guilds are included in the appendix

Leatherback turtle movements, dive behavior, and habitat characteristics in ecoregions of the Northwest Atlantic Ocean.

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Kara L Dodge

Full Text Available Leatherback sea turtles, Dermochelys coriacea, are highly migratory predators that feed exclusively on gelatinous zooplankton, thus playing a unique role in coastal and pelagic food webs. From 2007 to 2010, we used satellite telemetry to monitor the movements and dive behavior of nine adult and eleven subadult leatherbacks captured on the Northeast USA shelf and tracked throughout the Northwest Atlantic. Leatherback movements and environmental associations varied by oceanographic region, with slow, sinuous, area-restricted search behavior and shorter, shallower dives occurring in cool (median sea surface temperature: 18.4°C, productive (median chlorophyll a: 0.80 mg m(-3, shallow (median bathymetry: 57 m shelf habitat with strong sea surface temperature gradients (median SST gradient: 0.23°C km(-1 at temperate latitudes. Leatherbacks were highly aggregated in temperate shelf and slope waters during summer, early fall, and late spring and more widely dispersed in subtropical and tropical oceanic and neritic habitat during late fall, winter and early spring. We investigated the relationship of ecoregion, satellite-derived surface chlorophyll, satellite-derived sea surface temperature, SST gradient, chlorophyll gradient and bathymetry with leatherback search behavior using generalized linear mixed-effects models. The most well supported model showed that differences in leatherback search behavior were best explained by ecoregion and regional differences in bathymetry and SST. Within the Northwest Atlantic Shelves region, leatherbacks increased path sinuosity (i.e., looping movements with increasing SST, but this relationship reversed within the Gulf Stream region. Leatherbacks increased path sinuosity with decreasing water depth in temperate and tropical shelf habitats. This relationship is consistent with increasing epipelagic gelatinous zooplankton biomass with decreasing water depth, and bathymetry may be a key feature in identifying

Southern Great Plains Rapid Ecoregional Assessment: pre-assessment report

Science.gov (United States)

Assal, Timothy J.; Melcher, Cynthia P.; Carr, Natasha B.

2015-01-01

The purpose of the Pre-Assessment Report for the Southern Great Plains Rapid Ecoregional Assessment (REA) is to document the selection process for and final list of Conservation Elements, Change Agents, and Management Questions developed during Phase I. The overall goal of the REAs being conducted for the Bureau of Land Management (BLM) is to provide information that supports regional planning and analysis for the management of ecological resources. The REA provides an assessment of baseline ecological conditions, an evaluation of current risks from drivers of ecosystem change, and a predictive capacity for evaluating future risks. The REA also may be used for identifying priority areas for conservation or restoration and for assessing the cumulative effects of a variety of land uses. There are several components of the REAs. Management Questions, developed by the BLM and partners for the ecoregion, identify the information needed for addressing land-management responsibilities. Conservation Elements represent regionally significant terrestrial and aquatic species and communities that are to be conserved and (or) restored. For each Conservation Element, key ecological attributes will be evaluated to determine the status of each species and community. The REA also will evaluate major drivers of ecosystem change, or Change Agents, currently affecting or likely to affect the status of Conservation Elements in the future. The relationships between Change Agents and key ecological attributes will be summarized using conceptual models. The REA process is a two-phase process. Phase I (pre-assessment) includes developing and finalizing the lists of priority Management Questions, Conservation Elements, and Change Agents, culminating in the REA Pre-Assessment Report.

Fish and mussels: importance of fish for freshwater mussel conservation

Directory of Open Access Journals (Sweden)

Ronaldo Sousa

2015-12-01

Full Text Available Co-extinctions have received trivial consideration in discussions about the global conservation crisis, even though recent studies have emphasised their importance. This situation is even more pronounced in freshwater ecosystems where this phenomenon is largely unrecognized. In this presentation we explore the role of fish for freshwater mussels’ conservation. Freshwater mussels’ need fish as a host to complete their life cycle and given this premise is expected that changes in the fish community due to species extinctions or additions may have great effects. We reviewed the published information and we found: 1 that most of the studies were published in the last few years; 2 that most of the studies were performed in North America (69%, which is probably due to the high number of endemic threatened species in this continent; 3 that most of the mussel species that are specialists in fish hosting are listed as vulnerable or endangered (55%; 4 most studies were performed in laboratory (83% and 5 that the majority of studies were focused on life cycle or on identifying suitable fish hosts of freshwater mussel species with few studies focusing on threats. Since the interaction between fish and freshwater mussels can be easily disrupted and serious threats to this interaction have arisen (e.g. loss and fragmentation of habitat, changes in river flow, climate change, introduction of invasive species, pollution a more holistic approach is needed to find the best management strategies to conserve these animals. In addition, more field studies are required and more information on African, South American and Asian species is essential. Neglect the possible fundamental role of fish in the decline or extinction of freshwater mussels may impair the success of any measure devoted to their conservation; therefore, this issue cannot be ignored.

Protected area coverage of threatened vertebrates and ecoregions in Peru: Comparison of communal, private and state reserves.

Science.gov (United States)

Shanee, Sam; Shanee, Noga; Monteferri, Bruno; Allgas, Nestor; Alarcon Pardo, Alejandro; Horwich, Robert H

2017-11-01

Protected areas (PAs) are a conservation mainstay and arguably the most effective conservation strategy for species protection. As a 'megadiverse' country, Peru is a priority for conservation actions. Peruvian legislation allows for the creation of state PAs and private/communal PAs. Using publicly available species distribution and protected area data sets we evaluated the coverage of Threatened terrestrial vertebrate species distributions and ecoregions provided by both kinds of PA in Peru. Peru's state PA system covers 217,879 km 2 and private/communal PAs cover 16,588 km 2 . Of the 462 species of Threatened and Data Deficient species we evaluated, 75% had distributions that overlapped with at least one PA but only 53% had ≥10% of their distributions within PAs, with inclusion much reduced at higher coverage targets. Of the species we evaluated, 118 species are only found in national PAs and 29 species only found in private/communal PAs. Of the 17 terrestrial ecoregions found in Peru all are represented in PAs; the national PA system included coverage of 16 and private/communal PAs protect 13. One ecoregion is only protected in private/communal PAs, whereas four are only covered in national PAs. Our results show the important role private/communal PAs can play in the protection of ecological diversity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Montana Valley and Foothill Prairies Ecoregion: Chapter 6 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Taylor, Janis L.

2012-01-01

The Montana Valley and Foothill Prairies Ecoregion comprises numerous intermountain valleys and low-elevation foothill prairies spread across the western half of Montana, on both sides of the Continental Divide (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion, which covers approximately 64,658 km2 (24,965 mi2), includes the Flathead Valley and the valleys surrounding Helena, Missoula, Bozeman, Billings, Anaconda, Dillon, and Lewistown (fig. 1). These valleys are generally characterized by shortgrass prairie vegetation and are flanked by forested mountains (Woods and others, 1999); thus, the valleys’ biotas with regards to fish and insects are comparable. In many cases, the valleys are conduits for some of the largest rivers in the state, including Clark Fork and the Missouri, Jefferson, Madison, Flathead, Yellowstone, Gallatin, Smith, Big Hole, Bitterroot, and Blackfoot Rivers (fig. 2). The Montana Valley and Foothill Prairies Ecoregion also includes the “Rocky Mountain front,” an area of prairies along the eastern slope of the northern Rocky Mountains. Principal land uses within the ecoregion include farming, grazing, and mining. The valleys serve as major transportation and utility corridors and also contain the majority of Montana’s human population. The Montana Valley and Foothill Prairies Ecoregion extends into 17 mostly rural counties throughout western Montana. Only three of the counties—Carbon, Yellowstone, and Missoula—are part of a metropolitan statistical area with contiguous built-up areas tied to an employment center. Nearly two-thirds of Montana residents live in nonmetropolitan counties (Albrecht, 2008). Ten of the counties within the ecoregion had population growth rates greater than national averages (9–13 percent) between 1970 and 2000 (table 1). Ravalli and Gallatin Counties had the highest growth rates. Population growth was largely due to amenity-related inmigration and an economy dependent on tourism

Freshwater gastropods diversity hotspots: three new species from the Uruguay River (South America

Directory of Open Access Journals (Sweden)

Diego E. Gutiérrez Gregoric

2016-06-01

Full Text Available Background: The Atlantic Forest is globally one of the priority ecoregions for biodiversity conservation. In Argentina, it is represented by the Paranense Forest, which covers a vast area of Misiones Province between the Paraná and Uruguay rivers. The Uruguay River is a global hotspot of freshwater gastropod diversity, here mainly represented by Tateidae (genus Potamolithus and to a lesser extent Chilinidae. The family Chilinidae (Gastropoda, Hygrophila includes 21 species currently recorded in Argentina, and three species in the Uruguay River. The species of Chilinidae occur in quite different types of habitats, but generally in clean oxygenated water recording variable temperature ranges. Highly oxygenated freshwater environments (waterfalls and rapids are the most vulnerable continental environments. We provide here novel information on three new species of Chilinidae from environments containing waterfalls and rapids in the Uruguay River malacological province of Argentina. Materials and Methods: The specimens were collected in 2010. We analyzed shell, radula, and nervous and reproductive systems, and determined the molecular genetics. The genetic distance was calculated for two mitochondrial markers (cytochrome c oxidase subunit I–COI- and cytochrome b -Cyt b- for these three new species and the species recorded from the Misionerean, Uruguay River and Lower Paraná-Río de la Plata malacological provinces. In addition, the COI data were analyzed phylogenetically by the neighbor-joining and Bayesian inference techniques. Results: The species described here are different in terms of shell, radula and nervous and reproductive systems, mostly based on the sculpture of the penis sheath. Phylogenetic analyses grouped the three new species with those present in the Lower Paraná-Río de la Plata and Uruguay River malacological provinces. Discussion: Phylogenetic analyses confirm the separation between the Uruguay River and the Misionerean

Freshwater Fish Communities

Science.gov (United States)

Freshwater fish are ecologically important in stream ecosystems, and they provide people with significant food, recreation, and conservation value as biological indicator of freshwater streams. Historically, the streams and rivers of southern New England supported moderately dive...

Exploring Freshwater Science

Indian Academy of Sciences (India)

and long term studies on mapping freshwater biodiversity1. 1. R J Ranjit Daniels ... The hierarchical nature of stream organization offers opportunity to ecologists to ask .... threats, freshwater systems are losing their aesthetic value (Fig- ure 4).

Effects of climate change and wildfire on soil loss in the Southern Rockies Ecoregion

Science.gov (United States)

S. E. Litschert; D. M. Theobald; T. C. Brown

2014-01-01

Forests in the Southern Rockies Ecoregion surround the headwaters of several major rivers in the western and central US. Future climatic changes will increase the incidence of wildfire in those forests, and will likely lead to changes in downstream water quality, including sediment loads.We estimated soil loss under the historic climate and two IPCC climate change...

Freshwater and fish

International Nuclear Information System (INIS)

Saxen, R.

1997-01-01

Severe radioactive contamination of the freshwater environment could have serious consequences for both drinking water and fish. Most of the Nordic countries have an abundance of freshwater lakes and rivers. Finland alone has about 56,000 lakes, each with a surface area of 1 hectare or more. Nearly 10% of Finland's surface is covered with lakes and rivers. In Sweden, about 9% of the surface area is freshwater, in Norway about 5%, and in Denmark only about 2%. Freshwater plays a minor role in Iceland, but even there numerous rivers discharge from the volcanic soils to the Ocean. Cs-137 and 90 Sr are likely to be the most important radionuclides with respect to long term radioactive contamination of freshwater. If radioactive deposition occurs in the absence of snow and ice radionuclides will contaminate the surface water directly and may rapidly enter the aquatic food chain. Fish which eat contaminated plankton become contaminated almost immediately. Deposition during summer increases the transfer for radionuclides to fish since fish metabolism is faster during the warm season. During the cold period, fish metabolism is slow and thus uptake and excretion of radiocaesium are also slow. (EG)

Environmental changes on freshwater fish communities in South America in the last five decades: a case study in northeast Argentina.

Directory of Open Access Journals (Sweden)

Alejandra Volpedo

2017-01-01

Full Text Available Environmental changes together with other stressors, such as habitat destruction, may cause widespread extinctions, decrease in biodiversity and disrupt natural communities, resulting in novel species assemblages. South America has a large diversity of freshwater fishes with complex evolutionary histories, mainly due to the presence of a wide variety of aquatic environments. Argentina has experienced an increase in rainfall in the last five decades leading to important climatic and hydrological changes. These changes caused the displacement of the isohyets towards the west. This study reports changes in the composition of freshwater fishes in northeast Argentina during the last five decades, and investigated a causal relationship between the variation in fish assemblages and climate change. The changes in the distribution and composition of fish communities between 1962 and 2010 were analyzed in 22 stations. These stations were agrouped in relation to the ichthyogeographic provinces: Great Rivers province (GRp and Pampean province (Pp. The correlation between rainfall in relation to the number total species from each of the studied provinces showed a significant positive correlation in Pp and not correlation in GRp. The annual mean river discharge and the number of total species from each ecoregion showed a significant positive correlation in GRp, and not correlation in Pp. The results of this study strongly suggest that the rainfall variations and river discharges observed in northeast Argentina induced changes in the composition of fish assemblages that lead to the redistribution of fish species among ichthyogeographic provinces.

Standard methods for sampling freshwater fishes: Opportunities for international collaboration

Science.gov (United States)

Bonar, Scott A.; Mercado-Silva, Norman; Hubert, Wayne A.; Beard, Douglas; Dave, Göran; Kubečka, Jan; Graeb, Brian D. S.; Lester, Nigel P.; Porath, Mark T.; Winfield, Ian J.

2017-01-01

With publication of Standard Methods for Sampling North American Freshwater Fishes in 2009, the American Fisheries Society (AFS) recommended standard procedures for North America. To explore interest in standardizing at intercontinental scales, a symposium attended by international specialists in freshwater fish sampling was convened at the 145th Annual AFS Meeting in Portland, Oregon, in August 2015. Participants represented all continents except Australia and Antarctica and were employed by state and federal agencies, universities, nongovernmental organizations, and consulting businesses. Currently, standardization is practiced mostly in North America and Europe. Participants described how standardization has been important for management of long-term data sets, promoting fundamental scientific understanding, and assessing efficacy of large spatial scale management strategies. Academics indicated that standardization has been useful in fisheries education because time previously used to teach how sampling methods are developed is now more devoted to diagnosis and treatment of problem fish communities. Researchers reported that standardization allowed increased sample size for method validation and calibration. Group consensus was to retain continental standards where they currently exist but to further explore international and intercontinental standardization, specifically identifying where synergies and bridges exist, and identify means to collaborate with scientists where standardization is limited but interest and need occur.

Biodiversity on the brink: an assessment of conservation strategies for North American freshwater mussels

Science.gov (United States)

Wendell R. Haag; James D. Williams

2014-01-01

The North America freshwater mussel fauna has suffered an inordinately high recent extinction rate, and the small size and isolation of many remaining populations portends a continued diminishment of this fauna. Causes of extinction and imperilment are varied but revolve around massive habitat loss, deterioration, and fragmentation. The National Strategy for the...

Freshwater Fungal Infections

Directory of Open Access Journals (Sweden)

Dennis J. Baumgardner

2017-01-01

Full Text Available Fungal infections as a result of freshwater exposure or trauma are fortunately rare. Etiologic agents are varied, but commonly include filamentous fungi and Candida. This narrative review describes various sources of potential freshwater fungal exposure and the diseases that may result, including fungal keratitis, acute otitis externa and tinea pedis, as well as rare deep soft tissue or bone infections and pulmonary or central nervous system infections following traumatic freshwater exposure during natural disasters or near-drowning episodes. Fungal etiology should be suspected in appropriate scenarios when bacterial cultures or molecular tests are normal or when the infection worsens or fails to resolve with appropriate antibacterial therapy.

Pelagic larval duration predicts extinction risk in a freshwater fish clade

OpenAIRE

Douglas, Morgan; Keck, Benjamin P.; Ruble, Crystal; Petty, Melissa; Shute, J. R.; Rakes, Patrick; Hulsey, C. Darrin

2013-01-01

Pelagic larval duration (PLD) can influence evolutionary processes ranging from dispersal to extinction in aquatic organisms. Using estimates of PLD obtained from species of North American darters (Percidae: Etheostomatinae), we demonstrate that this freshwater fish clade exhibits surprising variation in PLD. Comparative analyses provide some evidence that higher stream gradients favour the evolution of shorter PLD. Additionally, similar to patterns in the marine fossil record in which lower ...

Exotic annual Bromus invasions: Comparisons among species and ecoregions in the western United States [Chapter 2

Science.gov (United States)

Matthew L. Brooks; Cynthia S. Brown; Jeanne C. Chambers; Carla M. D' Antonio; Jon E. Keeley; Jayne Belnap

2016-01-01

Exotic annual Bromus species are widely recognized for their potential to invade, dominate, and alter the structure and function of ecosystems. In this chapter, we summarize the invasion potential, ecosystem threats, and management strategies for different Bromus species within each of five ecoregions of the western United States. We characterize invasion...

Taxonomic composition and endemism of the helminth fauna of freshwater fishes of Mexico.

Science.gov (United States)

Salgado-Maldonado, Guillermo; Quiroz-Martínez, Benjamín

2013-01-01

We examine the taxonomic composition and endemism of adult helminth parasites of freshwater fishes of Mexico, with regard to the main hydrological basins of the country. A presence-absence matrix, including every species of adult helminth parasites of freshwater fishes from 23 Mexican hydrological basins was compiled and examined in this paper. The helminth fauna of freshwater fishes of Mexico consists of a large group of Central American Neotropical species (S = 119) and another set, less rich of Nearctic species (S = 48), which are distributed along with the families of its fish hosts; insufficient data preclude the assignation of three species. This fauna is composed predominantly by nematodes, trematodes, and monogeneans, which together contributed 86 % of the total species recorded; cestodes and acanthocephalans being the taxa with the least species recorded. Current data suggests a 22 % (37/170) endemism amongst helminths of freshwater fishes of Mexico. Data suggests that the isolation of bodies of water in the Mexican territory, mostly in the Neotropical areas of southeastern Mexico and in the central Altiplano Mexicano (Mexican Highland Plateau), with well delimited basins separated by orographic features, provided peculiar conditions that have been conducive to the diversification of a unique helminth fauna.

Effects of Nano-Titanium Dioxide on Freshwater Algal Population Dynamics

Science.gov (United States)

Kulacki, Konrad J.; Cardinale, Bradley J.

2012-01-01

To make predictions about the possible effects of nanomaterials across environments and taxa, toxicity testing must incorporate not only a variety of organisms and endpoints, but also an understanding of the mechanisms that underlie nanoparticle toxicity. Here, we report the results of a laboratory experiment in which we examined how titanium dioxide nanoparticles impact the population dynamics and production of biomass across a range of freshwater algae. We exposed 10 of the most common species of North American freshwater pelagic algae (phytoplankton) to five increasing concentrations of n-TiO2 (ranging from controls to 300 mg n-TiO2 L−1). We then examined the effects of n-TiO2 on the population growth rates and biomass production of each algal species over a period of 25 days. On average, increasing concentrations of n-TiO2 had no significant effects on algal growth rates (p = 0.376), even though there was considerable species-specific variation in responses. In contrast, exposure to n-TiO2 tended to increase maximum biomass achieved by species in culture (p = 0.06). Results suggest that titanium dioxide nanoparticles could influence certain aspects of population growth of freshwater phytoplankton, though effects are unlikely at environmentally relevant concentrations. PMID:23071735

Nutrient addition shifts plant community composition towards earlier flowering species in some prairie ecoregions in the U.S. Central Plains.

Directory of Open Access Journals (Sweden)

Lori Biederman

Full Text Available The distribution of flowering across the growing season is governed by each species' evolutionary history and climatic variability. However, global change factors, such as eutrophication and invasion, can alter plant community composition and thus change the distribution of flowering across the growing season. We examined three ecoregions (tall-, mixed, and short-grass prairie across the U.S. Central Plains to determine how nutrient (nitrogen (N, phosphorus, and potassium (+micronutrient addition alters the temporal patterns of plant flowering traits. We calculated total community flowering potential (FP by distributing peak-season plant cover values across the growing season, allocating each species' cover to only those months in which it typically flowers. We also generated separate FP profiles for exotic and native species and functional group. We compared the ability of the added nutrients to shift the distribution of these FP profiles (total and sub-groups across the growing season. In all ecoregions, N increased the relative cover of both exotic species and C3 graminoids that flower in May through August. The cover of C4 graminoids decreased with added N, but the response varied by ecoregion and month. However, these functional changes only aggregated to shift the entire community's FP profile in the tall-grass prairie, where the relative cover of plants expected to flower in May and June increased and those that flower in September and October decreased with added N. The relatively low native cover in May and June may leave this ecoregion vulnerable to disturbance-induced invasion by exotic species that occupy this temporal niche. There was no change in the FP profile of the mixed and short-grass prairies with N addition as increased abundance of exotic species and C3 graminoids replaced other species that flower at the same time. In these communities a disturbance other than nutrient addition may be required to disrupt phenological

Investigation of road salts and biotic stressors on freshwater wetland communities.

Science.gov (United States)

Jones, Devin K; Mattes, Brian M; Hintz, William D; Schuler, Matthew S; Stoler, Aaron B; Lind, Lovisa A; Cooper, Reilly O; Relyea, Rick A

2017-02-01

The application of road deicing salts has led to the salinization of freshwater ecosystems in northern regions worldwide. Increased chloride concentrations in lakes, streams, ponds, and wetlands may negatively affect freshwater biota, potentially threatening ecosystem services. In an effort to reduce the effects of road salt, operators have increased the use of salt alternatives, yet we lack an understanding of how these deicers affect aquatic communities. We examined the direct and indirect effects of the most commonly used road salt (NaCl) and a proprietary salt mixture (NaCl, KCl, MgCl 2 ), at three environmentally relevant concentrations (150, 470, and 780 mg Cl - /L) on freshwater wetland communities in combination with one of three biotic stressors (control, predator cues, and competitors). The communities contained periphyton, phytoplankton, zooplankton, and two tadpole species (American toads, Anaxyrus americanus; wood frogs, Lithobates sylvaticus). Overall, we found the two road salts did not interact with the natural stressors. Both salts decreased pH and reduced zooplankton abundance. The strong decrease in zooplankton abundance in the highest NaCl concentration caused a trophic cascade that resulted in increased phytoplankton abundance. The highest NaCl concentration also reduced toad activity. For the biotic stressors, predatory stress decreased whereas competitive stress increased the activity of both tadpole species. Wood frog survival, time to metamorphosis, and mass at metamorphosis all decreased under competitive stress whereas toad time to metamorphosis increased and mass at metamorphosis decreased. Road salts and biotic stressors can both affect freshwater communities, but their effects are not interactive. Copyright © 2016 Elsevier Ltd. All rights reserved.

Inhabitants of the Fresh-Water Community.

Science.gov (United States)

Jorgensen, Joseph; Schroeder, Marlene

This learner's guide is designed to assist middle school students in studying freshwater organisms. Following a brief introduction to freshwater ecology, simple line drawings facilitate the identification of plants and animals common to Florida's freshwater ecosystems. Emphasis of the short text which accompanies each illustration is upon the…

Diversity, distribution, and conservation status of the native freshwater fishes of the Southern United States

Science.gov (United States)

Melvin L. Warren; Brooks M. Burr; Stephen J. Walsh; Henry L. Bart; Robert C. Cashner; David A. Etnier; Byron J. Freeman; Bernard R. Kuhajda; Richard L. Mayden; Henry W. Robison; Stephen T. Ross; Wayne C. Starnes

2000-01-01

The Southeastern Fishes Council Technical Advisory Committee reviewed the diversity, distribution, and status of all native freshwater and diadromous fishes across 51 major drainage units of the Southern United States. The Southern United States supports more native fishes than any area of comparable size on the North American continent north of Mexico, but also has a...

Scale-based freshwater conservation planning: towards protecting freshwater biodiversity in KwaZulu-Natal, South Africa

CSIR Research Space (South Africa)

Rivers-Moore, NA

2011-01-01

Full Text Available River systems have strong linear linkages and require innovative solutions to capture these linkages from aquatic conservation planners. The authors applied an approach to freshwater conservation planning to freshwater ecosystems of Kwa...

Cadmium-binding proteins in midgut gland of freshwater crayfish Procambarus clarkii

Energy Technology Data Exchange (ETDEWEB)

Del Ramo, J.; Pastor, A.; Torreblanca, A.; Medina, J.; Diza-Mayans, J.

1989-02-01

Metallothioneins, metal binding proteins, were originally isolated and characterized by Margoshes and Vallee. These proteins have a high affinity for various heavy metals, particularly cadmium and mercury and have extensively been studied in mammals. Metal binding proteins have been observed in a variety of marine invertebrates; however, there is very little information available on metal binding proteins in freshwater invertebrates, and particularly in freshwater crustaceans. Cadmium is an ubiquitous non essential element which possesses high toxicity to aquatic organisms. Cadmium binding proteins observed in invertebrates have similar characteristics to mammalian metallothioneins. In 1978, the American red crayfish appeared in Albufera Lake and the surrounding rice fields (Valencia, Spain). Albufera Lake and the surrounding rice fields waters are subjected to very heavy loads of sewage and toxic industrial residues (including heavy metals) from the many urban and wastewaters in this area. In previous reports the authors studied the toxicity and accumulation of cadmium on Procambarus clarkii of Albufera Lake. This crayfish shows a high resistance to cadmium and a great accumulation rate of this metal in several tissues, including midgut gland. Since Procambarus clarkii shows a high resistance to cadmium, the presence of cadmium binding proteins (Cd-BP) in midgut gland of these crayfish would be expected. This report describes results on the characterization of Cd-BPs obtained from cadmium exposed crayfish Procambarus clarkii, demonstrating their presence in this freshwater crayfish.

Reclaiming freshwater sustainability in the Cadillac Desert

Science.gov (United States)

Sabo, John L.; Sinha, Tushar; Bowling, Laura C.; Schoups, Gerrit H.W.; Wallender, Wesley W.; Campana, Michael E.; Cherkauer, Keith A.; Fuller, Pam L.; Graf, William L.; Hopmans, Jan W.; Kominoski, John S.; Taylor, Carissa; Trimble, Stanley W.; Webb, Robert H.; Wohl, Ellen E.

2010-01-01

Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%.

First record of Triaenodes bicolor (Curtis, 1834) (Insecta: Trichoptera) from the Ecoregion Hellenic Western Balkans

OpenAIRE

Ibrahimi, Halil; Kuçi, Ruzhdi; Bilalli, Astrit; Gashi, Ermira

2017-01-01

We collected adult caddisfly specimens with entomological nets and ultraviolet light traps monthly from May to November 2012 in Brezne Lake situated in Dragash Municipality. During this investigation we found the Leptocerid species Triaenodes bicolor for the first time in Kosovo; it is also the first record for Ecoregion 6, Hellenic Western Balkans. Additionally, this is the first record of the genus Triaenodes from Kosovo. In total seven males and three females of this species were found. Tr...

Desalination - an alternative freshwater resource

International Nuclear Information System (INIS)

Shakaib, M.

2005-01-01

Global water constitutes 94 percent salt water that is from the oceans and 6% is in the form of freshwater. Out of this 6% freshwater approximately 27% is trapped in glaciers and 72% is underground. The sea water is important for transportation, fisheries. Oceans regulate climate through air sea interaction. However direct consumption of sea water is too salty to sustain human life. Water with a dissolved solids (salt) content generally below about 1000 milligrams per liter (mg/L) is considered acceptable for human consumption. The application of desalting technologies over the past 50 years have been in many of the arid zone where freshwater is available. Pakistan lies in the Sun Belt. It is considered a wide margin coastal belt (990 km), having an Exclusive Economic Zone of 240,000 km/sup 2/, that strokes trillion cubic meters of sea water that can be made available as freshwater source to meet the shortfall in the supply of domestic water through desalination along the coastal belt of Pakistan. The freshwater obtained from the other desalination processes is slightly expensive, but the cost of desalination can be considerably reduced provided that the available inexpensive or free waste energy is utilized mainly. (author)

The freshwater reservoir effect in radiocarbon dating

DEFF Research Database (Denmark)

Philippsen, Bente

case studies will show the degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants and animals, shows that age differences of up to 2000 years can occur within one river. In the Limfjord, freshwater influence......The freshwater reservoir effect can result in too high radiocarbon ages of samples from lakes and rivers, including the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. In my talk, I will explain the causes and consequences of this effect. Two...... caused reservoir ages to vary between 250 and 700 years during the period 5400 BC - AD 700. Finally, I will discuss the implications of the freshwater reservoir effect for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany....

Meeting ecological and societal needs for freshwater

Science.gov (United States)

Baron, Jill S.; Poff, N.L.; Angermeier, P.L.; Dahm, Clifford N.; Gleick, P.H.; Hairston, N.G.; Jackson, R.B.; Johnston, C.A.; Richter, B.D.; Steinman, A.D.

2002-01-01

Human society has used freshwater from rivers, lakes, groundwater, and wetlands for many different urban, agricultural, and industrial activities, but in doing so has overlooked its value in supporting ecosystems. Freshwater is vital to human life and societal well-being, and thus its utilization for consumption, irrigation, and transport has long taken precedence over other commodities and services provided by freshwater ecosystems. However, there is growing recognition that functionally intact and biologically complex aquatic ecosystems provide many economically valuable services and long-term benefits to society. The short-term benefits include ecosystem goods and services, such as food supply, flood control, purification of human and industrial wastes, and habitat for plant and animal life—and these are costly, if not impossible, to replace. Long-term benefits include the sustained provision of those goods and services, as well as the adaptive capacity of aquatic ecosystems to respond to future environmental alterations, such as climate change. Thus, maintenance of the processes and properties that support freshwater ecosystem integrity should be included in debates over sustainable water resource allocation.The purpose of this report is to explain how the integrity of freshwater ecosystems depends upon adequate quantity, quality, timing, and temporal variability of water flow. Defining these requirements in a comprehensive but general manner provides a better foundation for their inclusion in current and future debates about allocation of water resources. In this way the needs of freshwater ecosystems can be legitimately recognized and addressed. We also recommend ways in which freshwater ecosystems can be protected, maintained, and restored.Freshwater ecosystem structure and function are tightly linked to the watershed or catchment of which they are a part. Because riverine networks, lakes, wetlands, and their connecting groundwaters, are literally the �

Freshwater Availability and Constraints on Thermoelectric Power Generation in the Southeast U.S

International Nuclear Information System (INIS)

Feldman, David; Slough, Amanda; Garrett, Gary

2008-01-01

There is a myriad of uses to which our country's freshwater supply is currently committed. Together with increasing quantities of consumption, there are growing constraints on water availability. In our future there will be two elements of consumption at the forefront of concern: availability and efficiency. Availability of freshwater is the most important of these and is the subject of this report. To use water efficiently, we must first have it. Efficiency is key to ensuring availability for future needs. As population grows and economic and technology demands increase - especially for thermoelectric power - needs for freshwater will also increase. Thus, using our limited supplies of freshwater must be done as efficiently as possible. Thermoelectric generating industry is the largest user of our nation's water resources, including fresh, surface, ground, and saline water. Saline water use accounts for approximately 30% of thermoelectric use, while the remaining 70% is from freshwater sources. The U.S. Geological Survey (USGS) estimates that thermoelectric generation accounts for roughly 136,000 million gallons per day (MGD), or 39% of freshwater withdrawals. This ranks slightly behind agricultural irrigation as the top source of freshwater withdrawals in the U.S. in 2000. For Americans to preserve their standard of living and maintain a thriving economy it is essential that greater attention be paid to freshwater availability in efforts to meet energy demands - particularly for electric power. According to projections by the Energy Information Administration's (EIA) Annual Energy Outlook 2006 (AEO 2006) anticipated growth of thermoelectric generating capacity will be 22% between 2005 and 2030. In the 2007 Report, EIA estimates that capacity to grow from approximately 709 GW in 2005 to 862 GW in 20303. These large increases in generating capacity will result in increased water demands by thermoelectric power plants and greater competition over water between the

The freshwater reservoir effect in radiocarbon dating

DEFF Research Database (Denmark)

Philippsen, Bente

2013-01-01

of magnitude and degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14C years can occur within one river. The freshwater reservoir effect has also implications......The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. This includes the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. Water rich in dissolved ancient calcium carbonates, commonly known...... as hard water, is the most common reason for the freshwater reservoir effect. It is therefore also called hardwater effect. Although it has been known for more than 60 years, it is still less well-recognized by archaeologists than the marine reservoir effect. The aim of this study is to examine the order...

Variation in NAT2 acetylation phenotypes is associated with differences in food-producing subsistence modes and ecoregions in Africa

Czech Academy of Sciences Publication Activity Database

Podgorná, Eliška; Diallo, I.; Vangenot, Ch.; Sanchez-Mazas, A.; Sabbagh, A.; Černý, Viktor; Poloni, E. S.

2015-01-01

Roč. 15, č. 263 (2015) ISSN 1471-2148 R&D Projects: GA ČR GA13-37998S Institutional support: RVO:67985912 Keywords : NAT2 * acetylation polymorphism * African Sahel * pastoral nomads * subsistence mode * ecoregion * natural selection Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 3.406, year: 2015 http://www.biomedcentral.com/1471-2148/15/263

Status and Impacts of Arctic Freshwater Export

Science.gov (United States)

Haine, T. W. N.

2017-12-01

Large freshwater anomalies clearly exist in the Arctic Ocean. For example, liquid freshwater has accumulated in the Beaufort Gyre in the decade of the 2000s compared to 1980-2000, with an extra ≈5000 km3—about 25%—being stored. The sources of freshwater to the Arctic from precipitation and runoff have increased between these periods (most of the evidence comes from models). Despite flux increases from 2001 to 2011, it is uncertain if the marine freshwater source through Bering Strait for the 2000s has changed, as observations in the 1980s and 1990s are incomplete. The marine freshwater fluxes draining the Arctic through Fram and Davis straits are also insignificantly different. In this way, the balance of sources and sinks of freshwater to the Arctic, Canadian Arctic Archipelago (CAA), and Baffin Bay shifted to about 1200±730 km3yr-1 freshening the region, on average, during the 2000s. The observed accumulation of liquid freshwater is consistent with this increased supply and the loss of freshwater from sea ice (Figure, right). Evidence exists that such discharges can impact the Atlantic meridional overturning circulation, and hence Atlantic sector climate. Nevertheless, it appears that the observed AMOC variability since 2004, when high quality measurements began, is not attributable to anthropogenic influence. This work is based on, and updated from, Haine et al. (2015), Carmack et al. (2016), and Haine (2016). Haine, T. W. N. Ocean science: Vagaries of Atlantic overturning. Nature Geoscience, 9, 479-480, 10.1038/ngeo2748, 2016. T. W. N. Haine et al., Arctic Freshwater Export: Status, Mechanisms, and Prospects, Global Planetary Change, 125, 13-35, 10.1016/j.glopacha.2014.11.013, 2015. E. Carmack et al., Fresh water and its role in the Arctic Marine System: sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans. J. G. Res. Biogeosciences, 10.1002/2015JG003140, 2016.

Whitemouth croaker, Micropogonias furnieri, trapped in a freshwater coastal lagoon: a natural comparison of freshwater and marine influences on otolith chemistry

Directory of Open Access Journals (Sweden)

Cristiano Q. de Albuquerque

Full Text Available Strontium and barium incorporation into otoliths was compared between whitemouth croaker, Micropogonias furnieri, collected from an entrapped freshwater population (Mirim Lagoon and a normal marine/estuarine population in southern Brazil. Chemical analysis was performed using LA-ICPMS with the objective of validating the effects of marine and freshwater environments on Sr and Ba incorporation as a basis for further investigation of marine and freshwater connectivity of M. furnieri. The freshwater population was dominated by older fish with mean ±SD age of 34±1 y, whereas the coastal samples were dominated by younger fish of 14±7 y. Comparison of strontium and barium incorporation among otolith life-history profiles indicated significantly higher barium and lower strontium for the freshwater population compared to the marine population. Furthermore, comparison of otolith material deposited in the freshwater, estuarine and marine life-history phases demonstrated clear differences among these environments. Mean concentrations of strontium and barium in otoliths of M. furnieri were respectively 710 and 112 µg g-1 for freshwater, 2069 and 16.7 µg g-1 for estuarine, and 2990 and 2.7 µg g-1 for marine life-history phases. Barium concentrations in otoliths from the freshwater population of M. furnieri appeared high relative to other freshwater species. Strontium levels across life-history profiles of marine fish increased with age from 2000 to 2900 µg g-1, possibly indicating more time spent in marine than estuarine waters with age. In contrast, for the freshwater population, strontium levels decreased during the first year of life approximately to 700 µg g-1, and remained low and stable thereafter, consistent with the early life-history occurring in an estuarine environment prior to entrapment in Mirim Lagoon. The results confirm the strong and opposite effects of marine and freshwater environments on incorporation of barium and strontium into

Genetic Divergence between Freshwater and Marine Morphs of Alewife (Alosa pseudoharengus): A ‘Next-Generation’ Sequencing Analysis

Science.gov (United States)

Czesny, Sergiusz; Epifanio, John; Michalak, Pawel

2012-01-01

Alewife Alosa pseudoharengus, a small clupeid fish native to Atlantic Ocean, has recently (∼150 years ago) invaded the North American Great Lakes and despite challenges of freshwater environment its populations exploded and disrupted local food web structures. This range expansion has been accompanied by dramatic changes at all levels of organization. Growth rates, size at maturation, or fecundity are only a few of the most distinct morphological and life history traits that contrast the two alewife morphs. A question arises to what extent these rapidly evolving differences between marine and freshwater varieties result from regulatory (including phenotypic plasticity) or structural mutations. To gain insights into expression changes and sequence divergence between marine and freshwater alewives, we sequenced transcriptomes of individuals from Lake Michigan and Atlantic Ocean. Population specific single nucleotide polymorphisms were rare but interestingly occurred in sequences of genes that also tended to show large differences in expression. Our results show that the striking phenotypic divergence between anadromous and lake alewives can be attributed to massive regulatory modifications rather than coding changes. PMID:22438868

Late Pleistocene fishes of the Tennessee River Basin: an analysis of a late Pleistocene freshwater fish fauna from Bell Cave (site ACb-2) in Colbert County, Alabama, USA

OpenAIRE

Stephen J. Jacquemin; Jun A. Ebersole; William C. Dickinson; Charles N. Ciampaglio

2016-01-01

The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (?10,000 to 30,000 years B.P.) lead...

Venomics and antivenomics of Bothrops erythromelas from five geographic populations within the Caatinga ecoregion of northeastern Brazil

OpenAIRE

Jorge, Roberta Jeane B.; Monteiro, Helena S.A.; Gonçalves Machado, Larissa; Guarnieri, Míriam C.; Ximenes, Rafael M.; Borges Nojosa, Diva M.; de O. Luna, Karla P.; Zingali, Russolina B.; Corrêa Netto, Carlos; Gutiérrez, José María; Sanz, Libia; Calvete, Juan J.; Pla, Davinia

2015-01-01

The Caatinga lancehead, Bothrops erythromelas, is a medically relevant species, responsible for most of the snakebite accidents in most parts of its distribution range in northeastern Brazil. The spectrum and geographic variability of its venom toxins were investigated applying a venomics approach to venom pools from five geographic areas within the Caatinga ecoregion. Despite its wide habitat, populations of B. erythromelas from Ceará, Pernambuco, Juazeiro, Paraiba, and Ilha de Itaparica exh...

The presence of species of Pseudochironomus Malloch 1915 (Diptera: Chironomidae) in watercourses of Chaco Serrano Ecoregion (Argentina, South America).

Science.gov (United States)

Paggi, Analía C; Rodriguez Garay, Gretel N

2015-05-15

Male imagos of Pseudochironomus viridis (Kieffer) are redescribed, the immature stages are described and figured for the first time. During this study, larva and pupal exuviae associated to P. richardsoni (Malloch) were recorded for the first time for South America. The specimens were collected from a stream and a river in the Pampasic Hills System in the Chaco Serrano ecoregion of Argentina.

Native Freshwater Fish and Mussel Species Richness

Data.gov (United States)

U.S. Environmental Protection Agency — These data represent predicted current distributions of all native freshwater fish and freshwater mussels in the Middle-Atlantic region. The data are available for...

Sahyadria, a new genus of barbs (Teleostei: Cyprinidae from Western Ghats of India

Directory of Open Access Journals (Sweden)

R. Raghavan

2013-11-01

Full Text Available Redline Torpedo Barbs (Teleostei: Cyprinidae, comprising of two species, Puntius denisonii and P. chalakkudiensis, and six evolutionarily distinct lineages are endemic to the streams of the Western Ghats freshwater ecoregion in peninsular India. Based on molecular and osteological evidence, we demonstrate that these barbs comprise a distinct genus, for which we propose the name Sahyadria.

Field-based methods for evaluating the annual maximum specific conductivity tolerated by freshwater invertebrates

Data.gov (United States)

U.S. Environmental Protection Agency — Data includes chemical and biological samples from Ecoregion 69 in West Virginia. eco69_dupchem.csv: 1. Station-year with at least 6 conductivity samples, one in the...

Effects of Pollution on Freshwater Fish.

Science.gov (United States)

Brungs, W. A.; And Others

1978-01-01

Presents a literature review of the effects of pollution on freshwater fish, covering publications of 1976-77. This review includes: (1) water quality; (2) pesticide pollutants; (3) chemical pollutants; (4) miscellaneous pollutants; and (5) physical factors of pollution on freshwater fish. A list of 338 references is also presented. (HM)

Methods for preparing synthetic freshwaters.

Science.gov (United States)

Smith, E J; Davison, W; Hamilton-Taylor, J

2002-03-01

Synthetic solutions that emulate the major ion compositions of natural waters are useful in experiments aimed at understanding biogeochemical processes. Standard recipes exist for preparing synthetic analogues of seawater, with its relatively constant composition, but, due to the diversity of freshwaters, a range of compositions and recipes is required. Generic protocols are developed for preparing synthetic freshwaters of any desired composition. The major problems encountered in preparing hard and soft waters include dissolving sparingly soluble calcium carbonate, ensuring that the ionic components of each concentrated stock solution cannot form an insoluble salt and dealing with the supersaturation of calcium carbonate in many hard waters. For acidic waters the poor solubility of aluminium salts requires attention. These problems are overcome by preparing concentrated stock solutions according to carefully designed reaction paths that were tested using a combination of experiment and equilibrium modeling. These stock solutions must then be added in a prescribed order to prepare a final solution that is brought into equilibrium with the atmosphere. The example calculations for preparing hard, soft and acidic freshwater surrogates with major ion compositions the same as published analyses, are presented in a generalized fashion that should allow preparation of any synthetic freshwater according to its known analysis.

Review: Freshwater conservation planning in South Africa ...

African Journals Online (AJOL)

Review: Freshwater conservation planning in South Africa: Milestones to ... Water SA. Journal Home · ABOUT THIS JOURNAL · Advanced Search ... Since the 1970s, at approximately 10-year intervals, 4 national-scale freshwater conservation ...

The sociology of landowner interest in restoring fire-adapted, biodiverse habitats in the wildland-urban interface of Oregon's Willamette Valley ecoregion

Science.gov (United States)

Max Nielsen-Pincus; Robert G. Ribe; Bart R. Johnson

2011-01-01

In many parts of the world, the combined effects of wildfire, climate change, and population growth in the wildland-urban interface pose increasing risks to both people and biodiversity. These risks are exemplified in western Oregon's Willamette Valley Ecoregion, where population is projected to double by 2050 and climate change is expected to increase wildfire...

Freshwater crayfish invasions in South Africa: past, present and ...

African Journals Online (AJOL)

Freshwater crayfish invasions have been studied around the world, but less so in Africa, a continent devoid of native freshwater crayfish. The present study reviews historical and current information on alien freshwater crayfish species introduced into South Africa and aims to indicate which areas are at risk from invasion.

Farming of Freshwater Rainbow Trout in Denmark

DEFF Research Database (Denmark)

Jokumsen, Alfred; Svendsen, Lars Moeslund

Textbook on Farming of Freshwater Rainbow Trout in Denmark. Danish edition with the title: Opdræt af regnbueørred i Danmark......Textbook on Farming of Freshwater Rainbow Trout in Denmark. Danish edition with the title: Opdræt af regnbueørred i Danmark...

Exploring Freshwater Science

Indian Academy of Sciences (India)

Freshwater ecosystems and associated habitats harbor incrediblebiodiversity. They offer various ecosystem services andsustain human livelihoods. However, due to increasing developmentalpressure and rising water demand, these systemsare under huge threat. As a result, many aquatic species arefeared to become ...

Seasonal comparison of aquatic macroinvertebrate assemblages in a flooded coastal freshwater marsh

Science.gov (United States)

Kang, Sung-Ryong; King, Sammy L.

2013-01-01

Marsh flooding and drying may be important factors affecting aquatic macroinvertebrate density and distribution in coastal freshwater marshes. Limited availability of water as a result of drying in emergent marsh may decrease density, taxonomic diversity, and taxa richness. The principal objectives of this study are to characterize the seasonal aquatic macroinvertebrate assemblage in a freshwater emergent marsh and compare aquatic macroinvertebrate species composition, density, and taxonomic diversity to that of freshwater marsh ponds. We hypothesize that 1) freshwater emergent marsh has lower seasonal density and taxonomic diversity compared to that of freshwater marsh ponds; and 2) freshwater emergent marsh has lower taxa richness than freshwater marsh ponds. Seasonal aquatic macroinvertebrate density in freshwater emergent marsh ranged from 0 organisms/m2 (summer 2009) to 91.1 ± 20.53 organisms/m2 (mean ± SE; spring 2009). Density in spring was higher than in all other seasons. Taxonomic diversity did not differ and there were no unique species in the freshwater emergent marsh. Our data only partially support our first hypothesis as aquatic macroinvertebrate density and taxonomic diversity between freshwater emergent marsh and ponds did not differ in spring, fall, and winter but ponds supported higher macroinvertebrate densities than freshwater emergent marsh during summer. However, our data did not support our second hypothesis as taxa richness between freshwater emergent marsh and ponds did not statistically differ.

Field and model investigations of freshwater lenses in coastal aquifers

NARCIS (Netherlands)

Pauw, P.S.

2015-01-01

A major problem of sustaining freshwater supply from freshwater lens is the invasion of saline groundwater into a fresh groundwater body. In many coastal areas saltwater intrusion has led to well closure and reduced freshwater supply. Furthermore, in the future saltwater intrusion is expected to

Pelagic larval duration predicts extinction risk in a freshwater fish clade.

Science.gov (United States)

Douglas, Morgan; Keck, Benjamin P; Ruble, Crystal; Petty, Melissa; Shute, J R; Rakes, Patrick; Hulsey, C Darrin

2013-01-01

Pelagic larval duration (PLD) can influence evolutionary processes ranging from dispersal to extinction in aquatic organisms. Using estimates of PLD obtained from species of North American darters (Percidae: Etheostomatinae), we demonstrate that this freshwater fish clade exhibits surprising variation in PLD. Comparative analyses provide some evidence that higher stream gradients favour the evolution of shorter PLD. Additionally, similar to patterns in the marine fossil record in which lower PLD is associated with greater extinction probability, we found a reduced PLD in darter lineages was evolutionarily associated with extinction risk. Understanding the causes and consequences of PLD length could lead to better management and conservation of organisms in our increasingly imperiled aquatic environments.

Predicting freshwater habitat integrity using land-use surrogates

CSIR Research Space (South Africa)

Amis, MA

2007-04-01

Full Text Available Freshwater biodiversity is globally threatened due to human disturbances, but freshwater ecosystems have been accorded less protection than their terrestrial and marine counterparts. Few criteria exist for assessing the habitat integrity of rivers...

Restricted-range fishes and the conservation of Brazilian freshwaters.

Science.gov (United States)

Nogueira, Cristiano; Buckup, Paulo A; Menezes, Naercio A; Oyakawa, Osvaldo T; Kasecker, Thais P; Ramos Neto, Mario B; da Silva, José Maria C

2010-06-30

Freshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms) and translating these into conservation priorities on the ground remains a major challenge to biodiversity science, and depends directly on species occurrence data of high taxonomic and geographic resolution. Brazil harbors the richest freshwater ichthyofauna in the world, but knowledge on endemic areas and conservation in Brazilian rivers is still scarce. Using data on environmental threats and revised species distribution data we detect and delineate 540 small watershed areas harboring 819 restricted-range fishes in Brazil. Many of these areas are already highly threatened, as 159 (29%) watersheds have lost more than 70% of their original vegetation cover, and only 141 (26%) show significant overlap with formally protected areas or indigenous lands. We detected 220 (40%) critical watersheds overlapping hydroelectric dams or showing both poor formal protection and widespread habitat loss; these sites harbor 344 endemic fish species that may face extinction if no conservation action is in place in the near future. We provide the first analysis of site-scale conservation priorities in the richest freshwater ecosystems of the globe. Our results corroborate the hypothesis that freshwater biodiversity has been neglected in former conservation assessments. The study provides a simple and straightforward method for detecting freshwater priority areas based on endemism and threat, and represents a starting point for integrating freshwater and terrestrial conservation in representative and biogeographically consistent site-scale conservation strategies, that may be scaled-up following naturally linked drainage systems. Proper management (e. g. forestry code enforcement, landscape

length-weight relationhip of freshwater wild fish species

African Journals Online (AJOL)

Dr Naeem

2012-06-21

Jun 21, 2012 ... Length-weight (LWR) and length-length relationships (LLR) were determined for a freshwater catfish ... Key words: Mystus bleekeri, length-weight relationship, length-length relationship, predictive equations. INTRODUCTION. Mystus bleekeri (freshwater catfish Day, 1877), locally ..... fish farmers, Aquacult.

Exotic annual Bromus invasions: comparisons among species and ecoregions in the western United States

Science.gov (United States)

Brooks, Matthew L.; Brown, Cynthia S.; Chambers, Jeanne C.; D'Antonio, Carla M.; Keeley, Jon E.; Belnap, Jayne

2016-01-01

Exotic annual Bromus species are widely recognized for their potential to invade, dominate, and alter the structure and function of ecosystems. In this chapter, we summarize the invasion potential, ecosystem threats, and management strategies for different Bromus species within each of five ecoregions of the western United States. We characterize invasion potential and threats in terms of ecosystem resistance to Bromus invasion and ecosystem resilience to disturbance with an emphasis on the importance of fi re regimes. We also explain how soil temperature and moisture regimes can be linked to patterns of resistance and resilience and provide a conceptual framework that can be used to evaluate the relative potential for invasion and ecological impact of the dominant exotic annual Bromus species in the western United States.

The freshwater biodegradation potential of nine Alaskan oils

International Nuclear Information System (INIS)

Blenkinsopp, S.; Segy, G.

1997-01-01

Nine Alaskan representative crude oils and oil products with freshwater spill potential were collected, aged, and incubated in the presence of the standard freshwater inoculum for 28 days at 10 degrees C. Detailed analytical chemistry was performed on all samples to quantify compositional changes. All of the samples tested exhibited measurable hydrocarbon loss as a result of incubation with the freshwater inoculum. Total saturate and total n-alkane biodegradation were greatly enhanced when nutrients were present. The oil products Jet B Fuel and Diesel No. 2 appear to be more biodegradable than the Alaska North Slope and Cook Inlet crude oils tested, while the Bunker C/Diesel mixture appears to be less biodegradable than these crude oils. These results suggest that the screening procedures described here can provide useful information when applying bioremediation technology to the cleanup of selected oiled freshwater environments. 10 refs., 5 tabs., 13 figs

Threatened and Endangered Freshwater Fish and Mussel Species Richness

Data.gov (United States)

U.S. Environmental Protection Agency — These data represent predicted current distributions of all US listed Threatened and Endangered freshwater fish and freshwater mussels in the Middle-Atlantic region....

Disentangling the effects of a century of eutrophication and climate warming on freshwater lake fish assemblages.

Directory of Open Access Journals (Sweden)

Peter C Jacobson

Full Text Available Eutrophication and climate warming are profoundly affecting fish in many freshwater lakes. Understanding the specific effects of these stressors is critical for development of effective adaptation and remediation strategies for conserving fish populations in a changing environment. Ecological niche models that incorporated the individual effects of nutrient concentration and climate were developed for 25 species of fish sampled in standard gillnet surveys from 1,577 Minnesota lakes. Lake phosphorus concentrations and climates were hindcasted to a pre-disturbance period of 1896-1925 using existing land use models and historical temperature data. Then historical fish assemblages were reconstructed using the ecological niche models. Substantial changes were noted when reconstructed fish assemblages were compared to those from the contemporary period (1981-2010. Disentangling the sometimes opposing, sometimes compounding, effects of eutrophication and climate warming was critical for understanding changes in fish assemblages. Reconstructed abundances of eutrophication-tolerant, warmwater taxa increased in prairie lakes that experienced significant eutrophication and climate warming. Eutrophication-intolerant, warmwater taxa abundance increased in forest lakes where primarily climate warming was the stressor. Coolwater fish declined in abundance in both ecoregions. Large changes in modeled abundance occurred when the effects of both climate and eutrophication operated in the same direction for some species. Conversely, the effects of climate warming and eutrophication operated in opposing directions for other species and dampened net changes in abundance. Quantifying the specific effects of climate and eutrophication will allow water resource managers to better understand how lakes have changed and provide expectations for sustainable fish assemblages in the future.

Changing Arctic Ocean freshwater pathways.

Science.gov (United States)

Morison, James; Kwok, Ron; Peralta-Ferriz, Cecilia; Alkire, Matt; Rigor, Ignatius; Andersen, Roger; Steele, Mike

2012-01-04

Freshening in the Canada basin of the Arctic Ocean began in the 1990s and continued to at least the end of 2008. By then, the Arctic Ocean might have gained four times as much fresh water as comprised the Great Salinity Anomaly of the 1970s, raising the spectre of slowing global ocean circulation. Freshening has been attributed to increased sea ice melting and contributions from runoff, but a leading explanation has been a strengthening of the Beaufort High--a characteristic peak in sea level atmospheric pressure--which tends to accelerate an anticyclonic (clockwise) wind pattern causing convergence of fresh surface water. Limited observations have made this explanation difficult to verify, and observations of increasing freshwater content under a weakened Beaufort High suggest that other factors must be affecting freshwater content. Here we use observations to show that during a time of record reductions in ice extent from 2005 to 2008, the dominant freshwater content changes were an increase in the Canada basin balanced by a decrease in the Eurasian basin. Observations are drawn from satellite data (sea surface height and ocean-bottom pressure) and in situ data. The freshwater changes were due to a cyclonic (anticlockwise) shift in the ocean pathway of Eurasian runoff forced by strengthening of the west-to-east Northern Hemisphere atmospheric circulation characterized by an increased Arctic Oscillation index. Our results confirm that runoff is an important influence on the Arctic Ocean and establish that the spatial and temporal manifestations of the runoff pathways are modulated by the Arctic Oscillation, rather than the strength of the wind-driven Beaufort Gyre circulation.

Species diversity and distribution of freshwater crabs (Decapoda: Pseudothelphusidae inhabiting the basin of the Rio Grande de Térraba, Pacific slope of Costa Rica

Directory of Open Access Journals (Sweden)

Luis Rólier Lara

2013-09-01

Full Text Available During the last decades, knowledge on biodiversity of freshwater decapods has increased considerably; however, information about ecology of these crustaceans is scarce. Currently, the freshwater decapod fauna of Costa Rica is comprised by representatives of three families (Caridea: Palaemonidae and Atyidae; Brachyura: Pseudothelphusidae. The present study aims to describe the species diversity and distribution of freshwater crabs inhabiting the basin of the Rio Grande de Térraba, Pacific slope of Costa Rica, where the Instituto Costarricense de Electricidad (ICE plans to implement one of the largest damming projects in the region. Samples were collected in 39 locations at an altitude ranging from 20 to 1,225 m. Sampling was carried out during several months in 2007, 2009 and 2010. We collected a total of 661 crabs, comprising eight species of Pseudothelphusidae of three genera, representing 53% of the 15 pseudothelphusid crab species currently recorded from Costa Rica. The most common species was Ptychophallus paraxanthusi followed by P. tristani. Freshwater crabs were more frequently encountered in the middle-low region of the basin (between 311 and 600 m and less frequently in the medium-high basin (between 601 and 1,225 m. Ptychophallus paraxanthusi showed the widest distribution and was collected in altitudes ranging from 20 to 700 m. The Rio Grande de Térraba region can be considered as a relatively small, but highly diverse system. Therefore, any alteration of the basin of Rio Grande de Térraba, and especially the possible construction of a hydroelectric power plant, needs to be carefully analyzed to mitigate the damaging effects of this project on the freshwater crabs. More ecological information about freshwater crabs from Costa Rica and the Central American region are needed to reach a first reasonable overview on the ecological role of these decapods in freshwater systems.

Lysogenic infection in sub-tropical freshwater cyanobacteria cultures and natural blooms

NARCIS (Netherlands)

Steenhauer, L.M.; Pollard, P.C.; Brussaard, C.P.D.; Säwström, C.

2014-01-01

Lysogeny has been reported for a few freshwater cyanobacteria cultures, but it is unknown how prevalent it is in freshwater cyanobacteria in situ. Here we tested for lysogeny in (a) cultures of eight Australian species of subtropical freshwater cyanobacteria; (b) seven strains of one species:

Restricted-range fishes and the conservation of Brazilian freshwaters.

Directory of Open Access Journals (Sweden)

Cristiano Nogueira

Full Text Available BACKGROUND: Freshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms and translating these into conservation priorities on the ground remains a major challenge to biodiversity science, and depends directly on species occurrence data of high taxonomic and geographic resolution. Brazil harbors the richest freshwater ichthyofauna in the world, but knowledge on endemic areas and conservation in Brazilian rivers is still scarce. METHODOLOGY/PRINCIPAL FINDINGS: Using data on environmental threats and revised species distribution data we detect and delineate 540 small watershed areas harboring 819 restricted-range fishes in Brazil. Many of these areas are already highly threatened, as 159 (29% watersheds have lost more than 70% of their original vegetation cover, and only 141 (26% show significant overlap with formally protected areas or indigenous lands. We detected 220 (40% critical watersheds overlapping hydroelectric dams or showing both poor formal protection and widespread habitat loss; these sites harbor 344 endemic fish species that may face extinction if no conservation action is in place in the near future. CONCLUSIONS/SIGNIFICANCE: We provide the first analysis of site-scale conservation priorities in the richest freshwater ecosystems of the globe. Our results corroborate the hypothesis that freshwater biodiversity has been neglected in former conservation assessments. The study provides a simple and straightforward method for detecting freshwater priority areas based on endemism and threat, and represents a starting point for integrating freshwater and terrestrial conservation in representative and biogeographically consistent site-scale conservation strategies, that may be scaled-up following naturally linked

Vulnerability of European freshwater catchments to climate change.

Science.gov (United States)

Markovic, Danijela; Carrizo, Savrina F; Kärcher, Oskar; Walz, Ariane; David, Jonathan N W

2017-09-01

Climate change is expected to exacerbate the current threats to freshwater ecosystems, yet multifaceted studies on the potential impacts of climate change on freshwater biodiversity at scales that inform management planning are lacking. The aim of this study was to fill this void through the development of a novel framework for assessing climate change vulnerability tailored to freshwater ecosystems. The three dimensions of climate change vulnerability are as follows: (i) exposure to climate change, (ii) sensitivity to altered environmental conditions and (iii) resilience potential. Our vulnerability framework includes 1685 freshwater species of plants, fishes, molluscs, odonates, amphibians, crayfish and turtles alongside key features within and between catchments, such as topography and connectivity. Several methodologies were used to combine these dimensions across a variety of future climate change models and scenarios. The resulting indices were overlaid to assess the vulnerability of European freshwater ecosystems at the catchment scale (18 783 catchments). The Balkan Lakes Ohrid and Prespa and Mediterranean islands emerge as most vulnerable to climate change. For the 2030s, we showed a consensus among the applied methods whereby up to 573 lake and river catchments are highly vulnerable to climate change. The anthropogenic disruption of hydrological habitat connectivity by dams is the major factor reducing climate change resilience. A gap analysis demonstrated that the current European protected area network covers climate change. Priority should be placed on enhancing stakeholder cooperation at the major basin scale towards preventing further degradation of freshwater ecosystems and maintaining connectivity among catchments. The catchments identified as most vulnerable to climate change provide preliminary targets for development of climate change conservation management and mitigation strategies. © 2017 John Wiley & Sons Ltd.

Electromagnetic methods for mapping freshwater lenses on Micronesian atoll islands

Science.gov (United States)

Anthony, S.S.

1992-01-01

The overall shape of freshwater lenses can be determined by applying electromagnetic methods and inverse layered-earth modeling to the mapping of atoll island freshwater lenses. Conductivity profiles were run across the width of the inhabited islands at Mwoakilloa, Pingelap, and Sapwuahfik atolls of the Pohnpei State, Federated States of Micronesia using a dual-loop, frequency-domain, electromagnetic profiling system. Six values of apparent conductivity were recorded at each sounding station and were used to interpret layer conductivities and/or thicknesses. A three-layer model that includes the unsaturated, freshwater, and saltwater zones was used to simulate apparent-conductivity data measured in the field. Interpreted results were compared with chloride-concentration data from monitoring wells and indicate that the interface between freshwater and saltwater layers, defined from electromagnetic data, is located in the upper part of the transition zone, where the chloride-concentration profile shows a rapid increase with depth. The electromagnetic method can be used to interpret the thickness of the freshwater between monitoring wells, but can not be used to interpret the thickness of freshwater from monitoring wells to the margin of an island. ?? 1992.

Predicting freshwater habitat integrity using land-use surrogates

African Journals Online (AJOL)

2007-04-02

Apr 2, 2007 ... Quantification of potential surrogates of freshwater habitat integrity. We chose a series of land-use variables that might be suitable predictors for assessing freshwater habitat integrity from the land cover map (CSIR 2005) and added separate GIS surfaces for human population density and the distribution of ...

A Synopsis of Global Mapping of Freshwater Habitats and Biodiversity: Implications for Conservation

Energy Technology Data Exchange (ETDEWEB)

McManamay, Ryan A. [ORNL; Griffiths, Natalie A. [ORNL; DeRolph, Christopher R. [ORNL; Pracheil, Brenda M. [ORNL

2018-01-01

Accurately mapping freshwater habitats and biodiversity at high-resolutions across the globe is essential for assessing the vulnerability and threats to freshwater organisms and prioritizing conservation efforts. Since the 2000s, extensive efforts have been devoted to mapping global freshwater habitats (rivers, lakes, and wetlands), the spatial representation of which has changed dramatically over time with new geospatial data products and improved remote sensing technologies. Some of these mapping efforts, however, are still coarse representations of actual conditions. Likewise, the resolution and scope of global freshwater biodiversity compilation efforts have also increased, but are yet to mirror the spatial resolution and fidelity of mapped freshwater environments. In our synopsis, we find that efforts to map freshwater habitats have been conducted independently of those for freshwater biodiversity; subsequently, there is little congruence in the spatial representation and resolution of the two efforts. We suggest that global species distribution models are needed to fill this information gap; however, limiting data on habitat characteristics at scales that complement freshwater habitats has prohibited global high-resolution biogeography efforts. Emerging research trends, such as mapping habitat alteration in freshwater ecosystems and trait biogeography, show great promise in mechanistically linking global anthropogenic stressors to freshwater biodiversity decline and extinction risk.

Mechanical challenges to freshwater residency in sharks and rays.

Science.gov (United States)

Gleiss, Adrian C; Potvin, Jean; Keleher, James J; Whitty, Jeff M; Morgan, David L; Goldbogen, Jeremy A

2015-04-01

Major transitions between marine and freshwater habitats are relatively infrequent, primarily as a result of major physiological and ecological challenges. Few species of cartilaginous fish have evolved to occupy freshwater habitats. Current thought suggests that the metabolic physiology of sharks has remained a barrier to the diversification of this taxon in freshwater ecosystems. Here, we demonstrate that the physical properties of water provide an additional constraint for this species-rich group to occupy freshwater systems. Using hydromechanical modeling, we show that occurrence in fresh water results in a two- to three-fold increase in negative buoyancy for sharks and rays. This carries the energetic cost of lift production and results in increased buoyancy-dependent mechanical power requirements for swimming and increased optimal swim speeds. The primary source of buoyancy, the lipid-rich liver, offers only limited compensation for increased negative buoyancy as a result of decreasing water density; maintaining the same submerged weight would involve increasing the liver volume by very large amounts: 3- to 4-fold in scenarios where liver density is also reduced to currently observed minimal levels and 8-fold without any changes in liver density. The first data on body density from two species of elasmobranch occurring in freshwater (the bull shark Carcharhinus leucas, Müller and Henle 1839, and the largetooth sawfish Pristis pristis, Linnaeus 1758) support this hypothesis, showing similar liver sizes as marine forms but lower liver densities, but the greatest negative buoyancies of any elasmobranch studied to date. Our data suggest that the mechanical challenges associated with buoyancy control may have hampered the invasion of freshwater habitats in elasmobranchs, highlighting an additional key factor that may govern the predisposition of marine organisms to successfully establish in freshwater habitats. © 2015. Published by The Company of Biologists Ltd.

Microplastics ingestion by a common tropical freshwater fishing resource.

Science.gov (United States)

Silva-Cavalcanti, Jacqueline Santos; Silva, José Diego B; França, Elton José de; Araújo, Maria Christina Barbosa de; Gusmão, Felipe

2017-02-01

Microplastics pollution is widespread in marine ecosystems and a major threat to biodiversity. Nevertheless, our knowledge of the impacts of microplastics in freshwater environments and biota is still very limited. The interaction of microplastics with freshwater organisms and the risks associated with the human consumption of organisms that ingested microplastics remain major knowledge gaps. In this study, we assessed the ingestion of microplastics by Hoplosternum littorale, a common freshwater fish heavily consumed by humans in semi-arid regions of South America. We assessed the abundance and diversity of both plastic debris and other food items found in the gut of fishes caught by local fishermen. We observed that 83% of the fish had plastic debris inside the gut, the highest frequency reported for a fish species so far. Most of the plastic debris (88.6%) recovered from the guts of fish were microplastics (microplastics at the urbanized sections of the river, and that the ingestion of microplastics was negatively correlated with the diversity of other food items in the gut of individual fish. Nevertheless, microplastics ingestion appears to have a limited impact on H. littorale, and the consequences of human consumption of this fish were not assessed. Our results suggest freshwater biota are vulnerable to microplastics pollution and that urbanization is a major factor contributing to the pollution of freshwater environments with microplastics. We suggest the gut content of fish could be used as a tool for the qualitative assessment of microplastics pollution in freshwater ecosystems. Further research is needed to determine the processes responsible for the high incidence of microplastics ingestion by H. littorale, and to evaluate the risk posed to humans by the consumption of freshwater fish that ingested microplastics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Global impacts of energy demand on the freshwater resources of nations.

Science.gov (United States)

Holland, Robert Alan; Scott, Kate A; Flörke, Martina; Brown, Gareth; Ewers, Robert M; Farmer, Elizabeth; Kapos, Valerie; Muggeridge, Ann; Scharlemann, Jörn P W; Taylor, Gail; Barrett, John; Eigenbrod, Felix

2015-12-01

The growing geographic disconnect between consumption of goods, the extraction and processing of resources, and the environmental impacts associated with production activities makes it crucial to factor global trade into sustainability assessments. Using an empirically validated environmentally extended global trade model, we examine the relationship between two key resources underpinning economies and human well--being-energy and freshwater. A comparison of three energy sectors (petroleum, gas, and electricity) reveals that freshwater consumption associated with gas and electricity production is largely confined within the territorial boundaries where demand originates. This finding contrasts with petroleum, which exhibits a varying ratio of territorial to international freshwater consumption, depending on the origin of demand. For example, although the United States and China have similar demand associated with the petroleum sector, international freshwater consumption is three times higher for the former than the latter. Based on mapping patterns of freshwater consumption associated with energy sectors at subnational scales, our analysis also reveals concordance between pressure on freshwater resources associated with energy production and freshwater scarcity in a number of river basins globally. These energy-driven pressures on freshwater resources in areas distant from the origin of energy demand complicate the design of policy to ensure security of fresh water and energy supply. Although much of the debate around energy is focused on greenhouse gas emissions, our findings highlight the need to consider the full range of consequences of energy production when designing policy.

Freshwater flux to Sermilik Fjord, SE Greenland

Directory of Open Access Journals (Sweden)

S. H. Mernild

2010-10-01

Full Text Available Terrestrial inputs of freshwater flux to Sermilik Fjord, SE Greenland, were estimated, indicating ice discharge to be the dominant source of freshwater. A freshwater flux of 40.4 ± 4.9×10⁹ m³ y⁻¹ was found (1999–2008, with an 85% contribution originated from ice discharge (65% alone from Helheim Glacier, 11% from terrestrial surface runoff (from melt water and rain, 3% from precipitation at the fjord surface area, and 1% from subglacial geothermal and frictional melting due to basal ice motion. The results demonstrate the dominance of ice discharge as a primary mechanism for delivering freshwater to Sermilik Fjord. Time series of ice discharge for Helheim Glacier, Midgård Glacier, and Fenris Glacier were calculated from satellite-derived average surface velocity, glacier width, and estimated ice thickness, and fluctuations in terrestrial surface freshwater runoff were simulated based on observed meteorological data. These simulations were compared and bias corrected against independent glacier catchment runoff observations. Modeled runoff to Sermilik Fjord was variable, ranging from 2.9 ± 0.4×10⁹ m³ y⁻¹ in 1999 to 5.9 ± 0.9×10⁹ m³ y⁻¹ in 2005. The sub-catchment runoff of the Helheim Glacier region accounted for 25% of the total runoff to Sermilik Fjord. The runoff distribution from the different sub-catchments suggested a strong influence from the spatial variation in glacier coverage, indicating high runoff volumes, where glacier cover was present at low elevations.

Wnt signaling and polarity in freshwater sponges.

Science.gov (United States)

Windsor Reid, Pamela J; Matveev, Eugueni; McClymont, Alexandra; Posfai, Dora; Hill, April L; Leys, Sally P

2018-02-02

The Wnt signaling pathway is uniquely metazoan and used in many processes during development, including the formation of polarity and body axes. In sponges, one of the earliest diverging animal groups, Wnt pathway genes have diverse expression patterns in different groups including along the anterior-posterior axis of two sponge larvae, and in the osculum and ostia of others. We studied the function of Wnt signaling and body polarity formation through expression, knockdown, and larval manipulation in several freshwater sponge species. Sponge Wnts fall into sponge-specific and sponge-class specific subfamilies of Wnt proteins. Notably Wnt genes were not found in transcriptomes of the glass sponge Aphrocallistes vastus. Wnt and its signaling genes were expressed in archaeocytes of the mesohyl throughout developing freshwater sponges. Osculum formation was enhanced by GSK3 knockdown, and Wnt antagonists inhibited both osculum development and regeneration. Using dye tracking we found that the posterior poles of freshwater sponge larvae give rise to tissue that will form the osculum following metamorphosis. Together the data indicate that while components of canonical Wnt signaling may be used in development and maintenance of osculum tissue, it is likely that Wnt signaling itself occurs between individual cells rather than whole tissues or structures in freshwater sponges.

The role of fecundity and reproductive effort in defining life-history strategies of North American freshwater mussels.

Science.gov (United States)

Haag, Wendell R

2013-08-01

Selection is expected to optimize reproductive investment resulting in characteristic trade-offs among traits such as brood size, offspring size, somatic maintenance, and lifespan; relative patterns of energy allocation to these functions are important in defining life-history strategies. Freshwater mussels are a diverse and imperiled component of aquatic ecosystems, but little is known about their life-history strategies, particularly patterns of fecundity and reproductive effort. Because mussels have an unusual life cycle in which larvae (glochidia) are obligate parasites on fishes, differences in host relationships are expected to influence patterns of reproductive output among species. I investigated fecundity and reproductive effort (RE) and their relationships to other life-history traits for a taxonomically broad cross section of North American mussel diversity. Annual fecundity of North American mussel species spans nearly four orders of magnitude, ranging from 200000). Estimates of RE also were highly variable, ranging among species from 0.06 to 25.4%. Median fecundity and RE differed among phylogenetic groups, but patterns for these two traits differed in several ways. For example, the tribe Anodontini had relatively low median fecundity but had the highest RE of any group. Within and among species, body size was a strong predictor of fecundity and explained a high percentage of variation in fecundity among species. Fecundity showed little relationship to other life-history traits including glochidial size, lifespan, brooding strategies, or host strategies. The only apparent trade-off evident among these traits was the extraordinarily high fecundity of Leptodea, Margaritifera, and Truncilla, which may come at a cost of greatly reduced glochidial size; there was no relationship between fecundity and glochidial size for the remaining 61 species in the dataset. In contrast to fecundity, RE showed evidence of a strong trade-off with lifespan, which was

Why are freshwater fish so threatened?

Science.gov (United States)

Closs, Gerard P.; Angermeier, Paul; Darwall, William R.T.; Balcombe, Stephen R.

2015-01-01

The huge diversity of freshwater fishes is concentrated into an area of habitat that covers only about 1% of the Earth's surface, and much of this limited area has already been extensively impacted and intensively managed to meet human needs (Dudgeon et al., 2006). As outlined in Chapter 1, the number and proportions of threatened species tend to rise wherever fish diversity coincides with dense human populations, intensive resource use and development pressure. Of particular concern is the substantial proportion of the global diversity of freshwater fishes concentrated within the Mekong and Amazon Basins and west-central Africa (Berra, 2001; Abell et al., 2008; Dudgeon, 2011; Chapter 1) with extensive exploitation of water resources planned to accelerate in future years (Dudgeon, 2011; Chapter 1). If current trends continue, and the social, political and economic models that have been used to develop industrialised regions of the world over the past two centuries prevail, then the future of a significant proportion of global diversity of freshwater fish species is clearly uncertain.

Marine ecoregion and Deepwater Horizon oil spill affect recruitment and population structure of a salt marsh snail

Science.gov (United States)

Pennings, Steven C.; Zengel, Scott; Oehrig, Jacob; Alber, Merryl; Bishop, T. Dale; Deis, Donald R.; Devlin, Donna; Hughes, A. Randall; Hutchens, John J.; Kiehn, Whitney M.; McFarlin, Caroline R.; Montague, Clay L.; Powers, Sean P.; Proffitt, C. Edward; Rutherford, Nicolle; Stagg, Camille L.; Walters, Keith

2016-01-01

Marine species with planktonic larvae often have high spatial and temporal variation in recruitment that leads to subsequent variation in the ecology of benthic adults. Using a combination of published and unpublished data, we compared the population structure of the salt marsh snail, Littoraria irrorata, between the South Atlantic Bight and the Gulf Coast of the United States to infer geographic differences in recruitment and to test the hypothesis that the Deepwater Horizon oil spill led to widespread recruitment failure of L. irrorata in Louisiana in 2010. Size-frequency distributions in both ecoregions were bimodal, with troughs in the distributions consistent with a transition from sub-adults to adults at ~13 mm in shell length as reported in the literature; however, adult snails reached larger sizes in the Gulf Coast. The ratio of sub-adults to adults was 1.5–2 times greater in the South Atlantic Bight than the Gulf Coast, consistent with higher recruitment rates in the South Atlantic Bight. Higher recruitment rates in the South Atlantic Bight could contribute to higher snail densities and reduced adult growth in this region. The ratio of sub-adults to adults in Louisiana was lower in 2011 than in previous years, and began to recover in 2012–2014, consistent with widespread recruitment failure in 2010, when large expanses of spilled oil were present in coastal waters. Our results reveal an important difference in the ecology of a key salt marsh invertebrate between the two ecoregions, and also suggest that the Deepwater Horizon oil spill may have caused widespread recruitment failure in this species and perhaps others with similar planktonic larval stages.

Origin and evolutionary history of freshwater Rhodophyta: further insights based on phylogenomic evidence.

Science.gov (United States)

Nan, Fangru; Feng, Jia; Lv, Junping; Liu, Qi; Fang, Kunpeng; Gong, Chaoyan; Xie, Shulian

2017-06-07

Freshwater representatives of Rhodophyta were sampled and the complete chloroplast and mitochondrial genomes were determined. Characteristics of the chloroplast and mitochondrial genomes were analyzed and phylogenetic relationship of marine and freshwater Rhodophyta were reconstructed based on the organelle genomes. The freshwater member Compsopogon caeruleus was determined for the largest chloroplast genome among multicellular Rhodophyta up to now. Expansion and subsequent reduction of both the genome size and GC content were observed in the Rhodophyta except for the freshwater Compsopogon caeruleus. It was inferred that the freshwater members of Rhodophyta occurred through diverse origins based on evidence of genome size, GC-content, phylogenomic analysis and divergence time estimation. The freshwater species Compsopogon caeruleus and Hildenbrandia rivularis originated and evolved independently at the inland water, whereas the Bangia atropurpurea, Batrachospermum arcuatum and Thorea hispida are derived from the marine relatives. The typical freshwater representatives Thoreales and Batrachospermales are probably derived from the marine relative Palmaria palmata at approximately 415-484 MYA. The origin and evolutionary history of freshwater Rhodophyta needs to be testified with more organelle genome sequences and wider global sampling.

Freshwater savings from marine protein consumption

International Nuclear Information System (INIS)

Gephart, Jessica A; Pace, Michael L; D’Odorico, Paolo

2014-01-01

Marine fisheries provide an essential source of protein for many people around the world. Unlike alternative terrestrial sources of protein, marine fish production requires little to no freshwater inputs. Consuming marine fish protein instead of terrestrial protein therefore represents freshwater savings (equivalent to an avoided water cost) and contributes to a low water footprint diet. These water savings are realized by the producers of alternative protein sources, rather than the consumers of marine protein. This study quantifies freshwater savings from marine fish consumption around the world by estimating the water footprint of replacing marine fish with terrestrial protein based on current consumption patterns. An estimated 7 600 km 3  yr −1 of water is used for human food production. Replacing marine protein with terrestrial protein would require an additional 350 km 3  yr −1 of water, meaning that marine protein provides current water savings of 4.6%. The importance of these freshwater savings is highly uneven around the globe, with savings ranging from as little as 0 to as much as 50%. The largest savings as a per cent of current water footprints occur in Asia, Oceania, and several coastal African nations. The greatest national water savings from marine fish protein occur in Southeast Asia and the United States. As the human population increases, future water savings from marine fish consumption will be increasingly important to food and water security and depend on sustainable harvest of capture fisheries and low water footprint growth of marine aquaculture. (paper)

Sulfate reduction and methanogenesis at a freshwater

DEFF Research Database (Denmark)

Iversen, Vibeke Margrethe Nyvang; Andersen, Martin Søgaard; Jakobsen, Rasmus

The freshwater-seawater interface was studied in a ~9-m thick anaerobic aquifer located in marine sand and gravel with thin peat lenses. Very limited amounts of iron-oxides are present. Consequently, the dominating redox processes are sulfate reduction and methanogenesis, and the groundwater...... is enriched in dissolved sulfide, methane and bicarbonate. Under normal conditions the seawater-freshwater interface is found at a depth of 4 m at the coastline and reaches the bottom of the aquifer 40 m inland. However, occasional flooding of the area occurs, introducing sulfate to the aquifer. Groundwater...... chemistry was studied in a 120 m transect perpendicular to the coast. Cores were taken for radiotracer rate measurements of sulfate reduction and methanogenesis. In the saline part of the aquifer 35 m inland, sulfate reduction was the dominant process with rates of 0.1-10 mM/year. In the freshwater part 100...

The potential of freshwater macroalgae as a biofuels feedstock and the influence of nutrient availability on freshwater macroalgal biomass production

Science.gov (United States)

Yun, Jin-Ho

Extensive efforts have been made to evaluate the potential of microalgae as a biofuel feedstock during the past 4-5 decades. However, filamentous freshwater macroalgae have numerous characteristics that favor their potential use as an alternative algal feedstock for biofuels production. Freshwater macroalgae exhibit high rates of areal productivity, and their tendency to form dense floating mats on the water surface imply significant reductions in harvesting and dewater costs compared to microalgae. In Chapter 1, I reviewed the published literature on the elemental composition and energy content of five genera of freshwater macroalgae. This review suggested that freshwater macroalgae compare favorably with traditional bio-based energy sources, including terrestrial residues, wood, and coal. In addition, I performed a semi-continuous culture experiment using the common Chlorophyte genus Oedogonium to investigate whether nutrient availability can influence its higher heating value (HHV), productivity, and proximate analysis. The experimental study suggested that the most nutrient-limited growth conditions resulted in a significant increase in the HHV of the Oedogonium biomass (14.4 MJ/kg to 16.1 MJ/kg). Although there was no significant difference in productivity between the treatments, the average dry weight productivity of Oedogonium (3.37 g/m2/day) was found to be much higher than is achievable with common terrestrial plant crops. Although filamentous freshwater macroalgae, therefore, have significant potential as a renewable source of bioenergy, the ultimate success of freshwater macroalgae as a biofuel feedstock will depend upon the ability to produce biomass at the commercial-scale in a cost-effective and sustainable manner. Aquatic ecology can play an important role to achieve the scale-up of algal crop production by informing the supply rates of nutrients to the cultivation systems, and by helping to create adaptive production systems that are resilient to

Recent changes in the freshwater composition east of Greenland

NARCIS (Netherlands)

de Steur, L.; Pickart, R.S.; Torres, D.J.; Valdimarsson, H.

2015-01-01

Results from three hydrographic surveys across the East Greenland Current between 2011 and 2013 are presented with focus on the freshwater sources. End-member analysis using salinity, d18O, and nutrient data shows that while meteoric water dominated the freshwater content, a significant amount of

Having it both ways? Land use change in a U.S. midwestern agricultural ecoregion

Science.gov (United States)

Auch, Roger F.; Laingen, Chris R.

2015-01-01

Urbanization has been directly linked to decreases in area of agricultural lands and, as such, has been considered a threat to food security. Although the area of land used to produce food has diminished, often overlooked have been changes in agricultural output. The Eastern Corn Belt Plains (ECBP) is an important agricultural region in the U.S. Midwest. It has both gained a significant amount of urban land, primarily from the conversion of agricultural land between 1973 and 2000, and at the same time continued to produce ever-increasing quantities of agricultural products. By 2002, more corn, soybeans, and hogs were produced on a smaller agricultural land base than in 1974. In the last quarter of the twentieth century, ECBP ecoregion society appeared to have “had it both ways”: more urbanization along with increased agricultural output.

Analysis of consumer behavior in decision making of purchasing ornamental freshwater fish (case of study at ornamental freshwater fish market at Peta Street, Bandung)

Science.gov (United States)

Gumilar, I.; Rizal, A.; Sriati; Setiawan Putra, R.

2018-04-01

This research aim was to analyzed process of decision making of purchasing ornamental freshwater fish at Peta Street, Bandung City and Analyzed what factors are driving consumers to buy freshwater fish Peta Street. The method used in this research is case study with rating scale and rank spearman analysis. The sampling technique is the accidental random sampling method consist of 30 respondents. The consumer’s decision making process consist of five stages, namely the recognition of needs, information searching, alternative evaluation, process of purchasing, and the evaluation of results. The results showed that at the stage of recognition of needs the motivation of purchasing freshwater fish because respondents are very fond of ornamental freshwater fish, at the stage of information search, the information sources are from the print media and friends or neighborhood. At the stage of alternative evaluation, the reason consumers buy ornamental freshwater fish because the quality of good products. The stage of purchasing decision process consumers bought 1-5 fish with frequency of purchase 1 time per month. The evaluation of results of post-purchasing consumers feel very satisfied with the fish products and the price is very affordable. To observe the factors that influence purchasing motivation of consumers, spearman rank test is the method. The results showed that the quality and price of the product are the factors that most influence the purchase decision of ornamental freshwater fish with the range of student-t value 3,968 and 2,107.

Freshwater Treatment and Test Facility

Data.gov (United States)

Federal Laboratory Consortium — The Freshwater Treatment and Test Facility, located at SANGB, has direct year-round access to water from Lake St. Clair and has a State of Michigan approved National...

Lama guanicoe remains from the Chaco ecoregion (Córdoba, Argentina): An osteological approach to the characterization of a relict wild population.

Science.gov (United States)

Costa, Thiago; Barri, Fernando

2018-01-01

Guanacos (Lama guanicoe) are large ungulates that have been valued by human populations in South America since the Late Pleistocene. Even though they were very abundant until the end of the 19th century (before the high deforestation rate of the last decades), guanacos have nearly disappeared in the Gran Chaco ecoregion, with relicts and isolated populations surviving in some areas, such as the shrubland area near the saline depressions of Córdoba province, Argentina. In this report, we present the first data from a locally endangered guanaco wild population, through the study of skeletal remains recovered in La Providencia ranch. Our results showed that most of the elements belonged to adults aged between 36 and 96 months; sex evaluation showed similar numbers of males and females. Statistical analysis of the body size of modern samples from Córdoba demonstrated that guanacos from the Chaco had large dimensions and presented lower size variability than the modern and archaeological specimens in our database. Moreover, they exhibited dimensions similar to those of modern guanacos from Patagonia and San Juan, and to archaeological specimens from Ongamira and Cerro Colorado, although further genetic studies are needed to corroborate a possible phylogenetic relationship. Finally, we used archaeozoological techniques to provide a first characterization of a relict guanaco population from the Chaco ecoregion, demonstrating its value to the study of modern skeletal remains and species conservation biology.

Pesticides in Brazilian freshwaters: a critical review.

Science.gov (United States)

Albuquerque, A F; Ribeiro, J S; Kummrow, F; Nogueira, A J A; Montagner, C C; Umbuzeiro, G A

2016-07-13

The widespread use of pesticides in agriculture can lead to water contamination and cause adverse effects on non-target organisms. Brazil has been the world's top pesticide market consumer since 2008, with 381 approved pesticides for crop use. This study provides a comprehensive literature review on the occurrence of pesticide residues in Brazilian freshwaters. We searched for information in official agency records and peer-reviewed scientific literature. Risk quotients were calculated to assess the potential risk posed to aquatic life by the individual pesticides based on their levels of water contamination. Studies about the occurrence of pesticides in freshwaters in Brazil are scarce and concentrated in few sampling sites in 5 of the 27 states. Herbicides (21) accounted for the majority of the substances investigated, followed by fungicides (11), insecticides (10) and plant growth regulators (1). Insecticides are the class of major concern. Brazil would benefit from the implementation of a nationwide pesticide freshwater monitoring program to support preventive, remediation and enforcement actions.

Water availability reconstructions using tree-rings in the Valdivian rainforest ecoregion, Chile

International Nuclear Information System (INIS)

Urrutia, Rocio; Pena, M P; Christie, Duncan A; Lara, Antonio

2010-01-01

Water availability can be considered as one of the main restrictions for future development in South-Central Chile, due to the reported decreasing trends in precipitation in the last decades and the increasing demand for this resource. This issue makes the study of past water availability fundamental for the understanding of present and future variations. This paper presents a comparison of two water availability reconstructions within the Valdivian rainforest ecoregion (35 0 -48 0 S), one corresponding to a precipitation (37 0 -39.5 0 S) and the other to a streamflow reconstruction (41 0 S). This study shows that there are fundamental differences between them especially in the long term variability. However, there are also coincidences, mainly at higher frequency variations, such as at a bidecadal, decadal and annual scale. Another important finding is that these reconstructions show significant correlations with different climatic forcings in this area. The northern reconstruction presents a significant relationship with ENSO (El Nino Southern Oscillation), while the southern does the same with the AAO (Antarctic Oscillation Index).

Cable Bacteria in Freshwater Sediments

DEFF Research Database (Denmark)

Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

2015-01-01

In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

New Zealand Freshwater Management: Changing Policy for a Changing World

Science.gov (United States)

Rouse, H. L.; Norton, N.

2014-12-01

Fresh water is essential to New Zealand's economic, environmental, cultural and social well-being. In line with global trends, New Zealand's freshwater resources are under pressure from increased abstraction and changes in land-use which contribute contaminants to our freshwater systems. Recent central government policy reform introduces greater national direction and guidance, to bring about a step-change in freshwater management. An existing national policy for freshwater management introduced in 2011 requires regional authorities to produce freshwater management plans containing clear freshwater objectives (measurable statements about the desired environmental state for water bodies) and associated limits to resource use (such as environmental flows and quantity allocation limits, and loads of contaminants to be discharged). These plans must integrate water quantity and quality management, consider climate change, and incorporate tangata whenua (New Zealand māori) roles and interests. In recent (2014) national policy amendments, the regional authorities are also required to implement national 'bottom-line' standards for certain attributes of the system to be managed; undertake accounting for all water takes and all sources of contaminants; and to develop and implement their plans in a collaborative way with communities. This rapid change in national policy has necessitated a new way of working for authorities tasked with implementation; many obstacles lie in their path. The scientific methods required to help set water quantity limits are well established, but water quality methods are less so. Collaborative processes have well documented benefits but also raise many challenges, particularly for the communication of complex and often uncertain scientific information. This paper provides background on the national policy changes and offers some early lessons learned by the regional authorities implementing collaborative freshwater management in New Zealand.

Stormwater runoff drives viral community composition changes in inland freshwaters

Science.gov (United States)

Williamson, Kurt E.; Harris, Jamie V.; Green, Jasmin C.; Rahman, Faraz; Chambers, Randolph M.

2014-01-01

Storm events impact freshwater microbial communities by transporting terrestrial viruses and other microbes to freshwater systems, and by potentially resuspending microbes from bottom sediments. The magnitude of these impacts on freshwater ecosystems is unknown and largely unexplored. Field studies carried out at two discrete sites in coastal Virginia (USA) were used to characterize the viral load carried by runoff and to test the hypothesis that terrestrial viruses introduced through stormwater runoff change the composition of freshwater microbial communities. Field data gathered from an agricultural watershed indicated that primary runoff can contain viral densities approximating those of receiving waters. Furthermore, viruses attached to suspended colloids made up a large fraction of the total load, particularly in early stages of the storm. At a second field site (stormwater retention pond), RAPD-PCR profiling showed that the viral community of the pond changed dramatically over the course of two intense storms while relatively little change was observed over similar time scales in the absence of disturbance. Comparisons of planktonic and particle-associated viral communities revealed two completely distinct communities, suggesting that particle-associated viruses represent a potentially large and overlooked portion of aquatic viral abundance and diversity. Our findings show that stormwater runoff can quickly change the composition of freshwater microbial communities. Based on these findings, increased storms in the coastal mid-Atlantic region predicted by most climate change models will likely have important impacts on the structure and function of local freshwater microbial communities. PMID:24672520

Ammonium transformation in a nitrogen-rich tidal freshwater marsh

DEFF Research Database (Denmark)

Gribsholt, B.; Andersson, M.; Boschker, H.T.S.

2006-01-01

The fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrient rich Scheldt River, Belgium, was quantified in a whole ecosystem 15N labeling experiment. In late summer (September) we added 15N-NH4+ to the flood water entering a 3477 m2 tidal freshwater marsh...

Genome-Wide DNA Methylation Profiling Reveals Epigenetic Adaptation of Stickleback to Marine and Freshwater Conditions.

Science.gov (United States)

Artemov, Artem V; Mugue, Nikolai S; Rastorguev, Sergey M; Zhenilo, Svetlana; Mazur, Alexander M; Tsygankova, Svetlana V; Boulygina, Eugenia S; Kaplun, Daria; Nedoluzhko, Artem V; Medvedeva, Yulia A; Prokhortchouk, Egor B

2017-09-01

The three-spined stickleback (Gasterosteus aculeatus) represents a convenient model to study microevolution-adaptation to a freshwater environment. Although genetic adaptations to freshwater environments are well-studied, epigenetic adaptations have attracted little attention. In this work, we investigated the role of DNA methylation in the adaptation of the marine stickleback population to freshwater conditions. DNA methylation profiling was performed in marine and freshwater populations of sticklebacks, as well as in marine sticklebacks placed into a freshwater environment and freshwater sticklebacks placed into seawater. We showed that the DNA methylation profile after placing a marine stickleback into fresh water partially converged to that of a freshwater stickleback. For six genes including ATP4A ion pump and NELL1, believed to be involved in skeletal ossification, we demonstrated similar changes in DNA methylation in both evolutionary and short-term adaptation. This suggested that an immediate epigenetic response to freshwater conditions can be maintained in freshwater population. Interestingly, we observed enhanced epigenetic plasticity in freshwater sticklebacks that may serve as a compensatory regulatory mechanism for the lack of genetic variation in the freshwater population. For the first time, we demonstrated that genes encoding ion channels KCND3, CACNA1FB, and ATP4A were differentially methylated between the marine and the freshwater populations. Other genes encoding ion channels were previously reported to be under selection in freshwater populations. Nevertheless, the genes that harbor genetic and epigenetic changes were not the same, suggesting that epigenetic adaptation is a complementary mechanism to selection of genetic variants favorable for freshwater environment. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Gene Expression in the Three-Spined Stickleback (Gasterosteus aculeatus) of Marine and Freshwater Ecotypes.

Science.gov (United States)

Rastorguev, S M; Nedoluzhko, A V; Gruzdeva, N M; Boulygina, E S; Tsygankova, S V; Oshchepkov, D Y; Mazur, A M; Prokhortchouk, E B; Skryabin, K G

2018-01-01

Three-spine stickleback (Gasterosteus aculeatus) is a well-known model organism that is routinely used to explore microevolution processes and speciation, and the number of studies related to this fish has been growing recently. The main reason for the increased interest is the processes of freshwater adaptation taking place in natural populations of this species. Freshwater three-spined stickleback populations form when marine water three-spined sticklebacks fish start spending their entire lifecycle in freshwater lakes and streams. To boot, these freshwater populations acquire novel biological traits during their adaptation to a freshwater environment. The processes taking place in these populations are of great interest to evolutionary biologists. Here, we present differential gene expression profiling in G. aculeatus gills, which was performed in marine and freshwater populations of sticklebacks. In total, 2,982 differentially expressed genes between marine and freshwater populations were discovered. We assumed that differentially expressed genes were distributed not randomly along stickleback chromosomes and that they are regularly observed in the "divergence islands" that are responsible for stickleback freshwater adaptation.

The effectiveness of surrogate taxa to conserve freshwater biodiversity

Science.gov (United States)

Stewart, David R.; Underwood, Zachary E.; Rahel, Frank J.; Walters, Annika W.

2018-01-01

Establishing protected areas has long been an effective conservation strategy, and is often based on more readily surveyed species. The potential of any freshwater taxa to be a surrogate of other aquatic groups has not been fully explored. We compiled occurrence data on 72 species of freshwater fish, amphibians, mussels, and aquatic reptiles for the Great Plains, Wyoming. We used hierarchical Bayesian multi-species mixture models and MaxEnt models to describe species distributions, and program Zonation to identify conservation priority areas for each aquatic group. The landscape-scale factors that best characterized aquatic species distributions differed among groups. There was low agreement and congruence among taxa-specific conservation priorities (<20%), meaning that no surrogate priority areas would include or protect the best habitats of other aquatic taxa. We found that common, wide-ranging aquatic species were included in taxa-specific priority areas, but rare freshwater species were not included. Thus, the development of conservation priorities based on a single freshwater aquatic group would not protect all species in the other aquatic groups.

Freshwater exposure pathways in the Nordic countries

International Nuclear Information System (INIS)

Tveten, U.

1984-06-01

The report relates to a subproject under a Nordic project called ''Large reactor accidents - consequences and mitigating actions''. The report summarizes information available, primarily in the Nordic countries, on freshwater exposure pathways. Experimental and theoretical data concerning the deposition and run-off of the nuclides *sp90*Sr and*Sp137*Cs is presented. Internal exposure via drinking water and freshwater fish is dealt with, as well as external exposure due to swimming, boating, contact with fishing utensils and use of beach areas. In addition is exposure via irrigated agricultural products considered. (RF)

Biota connect aquatic habitats throughout freshwater ecosystem mosaics

Science.gov (United States)

Schofield, Kate A.; Alexander, Laurie C.; Ridley, Caroline E.; Vanderhoof, Melanie; Fritz, Ken M.; Autrey, Bradley; DeMeester, Julie; Kepner, William G.; Lane, Charles R.; Leibowitz, Scott; Pollard, Amina I.

2018-01-01

Freshwater ecosystems are linked at various spatial and temporal scales by movements of biota adapted to life in water. We review the literature on movements of aquatic organisms that connect different types of freshwater habitats, focusing on linkages from streams and wetlands to downstream waters. Here, streams, wetlands, rivers, lakes, ponds, and other freshwater habitats are viewed as dynamic freshwater ecosystem mosaics (FEMs) that collectively provide the resources needed to sustain aquatic life. Based on existing evidence, it is clear that biotic linkages throughout FEMs have important consequences for biological integrity and biodiversity. All aquatic organisms move within and among FEM components, but differ in the mode, frequency, distance, and timing of their movements. These movements allow biota to recolonize habitats, avoid inbreeding, escape stressors, locate mates, and acquire resources. Cumulatively, these individual movements connect populations within and among FEMs and contribute to local and regional diversity, resilience to disturbance, and persistence of aquatic species in the face of environmental change. Thus, the biological connections established by movement of biota among streams, wetlands, and downstream waters are critical to the ecological integrity of these systems. Future research will help advance our understanding of the movements that link FEMs and their cumulative effects on downstream waters.

A SPATIAL DECISION SUPPORT SYSTEM FOR ECOTOURISM DEVELOPMENT IN CASPIAN HYRCANIAN MIXED FORESTS ECOREGION

Directory of Open Access Journals (Sweden)

ALI BALI

Full Text Available Ecotourism, as a form of sustainable nature-based tourism, promotes conservation of ecological and scenic values. In this study, a Spatial Decision Support System, SDSS, was developed based upon Multi Criteria Evaluation, MCE, for ecotourism development in the Caspian Hyrcanian Mixed Forests ecoregion, northern Iran. For this, important criteria and constraints for ecotourism development were shortlisted using the Delphi Method. The criteria were weighted using Analytical Hierarchy Process, AHP. The obtained results indicated that "distance from water resources", "land use", "slope", "soil", "climate", "distance from roads", "land cover density", "erosion", and "distance from residential areas" were the most important criteria, respectively. The findings suggest that GIS-based SDSS is suitable to engage the various criteria affecting the development of ecotourism destinations. This empirical research develops a new method that can significantly facilitate planning forecotourism development with respect to ecological capability of ecotourism destinations.

Consumption of freshwater fish by recreational and native freshwater anglers in the upper St-Maurice (Quebec, Canada) and estimation of the intake of methylmercury in humans

International Nuclear Information System (INIS)

Loranger, S.; Houde, L.; Schetagne, R.

1995-01-01

Hydro-Quebec is planning to build two hydroelectric reservoirs in the upper Saint-Maurice River, which would flood about 80% of the surrounding area. The methylmercury (MeHg) content in freshwater fish will therefore tend to increase during the first few years. This development will have a direct impact on the amount of MeHg that the actual users of this river section are exposed to. The objective of this study is to assess the consumption of local fish of these target groups using a Monte-Carlo approach. This study is part of a larger research project aimed at assessing human exposure and the health risks related to MeHg contamination in local fish. The fish consumption rate for recreational freshwater anglers was calculated using the duration of the average annual fishing trip, the average number of catches per species, the average fish weight per species exceeding a specific length of fish usually caught, and the edible portion of fish consumed. This rate was calculated for the native communities based on the total number of meals per year per species, the average fish weight per species, and the edible portion. Based on these calculations, average intake for sport fishermen is estimated at 6.9 g/day (sd = 6.4). This value is 5 to 25 times lower on average than for other North American native communities. However, it must be pointed out that the food habits of the native population were very similar to those of non-native populations; less than 30% of the food comes from traditional sources

Bistability of mangrove forests and competition with freshwater plants

Science.gov (United States)

Jiang, Jiang; Fuller, Douglas O; Teh, Su Yean; Zhai, Lu; Koh, Hock Lye; DeAngelis, Donald L.; Sternberg, L.D.S.L.

2015-01-01

Halophytic communities such as mangrove forests and buttonwood hammocks tend to border freshwater plant communities as sharp ecotones. Most studies attribute this purely to underlying physical templates, such as groundwater salinity gradients caused by tidal flux and topography. However, a few recent studies hypothesize that self-reinforcing feedback between vegetation and vadose zone salinity are also involved and create a bistable situation in which either halophytic dominated habitat or freshwater plant communities may dominate as alternative stable states. Here, we revisit the bistability hypothesis and demonstrate the mechanisms that result in bistability. We demonstrate with remote sensing imagery the sharp boundaries between freshwater hardwood hammock communities in southern Florida and halophytic communities such as buttonwood hammocks and mangroves. We further document from the literature how transpiration of mangroves and freshwater plants respond differently to vadose zone salinity, thus altering the salinity through feedback. Using mathematical models, we show how the self-reinforcing feedback, together with physical template, controls the ecotones between halophytic and freshwater communities. Regions of bistability along environmental gradients of salinity have the potential for large-scale vegetation shifts following pulse disturbances such as hurricane tidal surges in Florida, or tsunamis in other regions. The size of the region of bistability can be large for low-lying coastal habitat due to the saline water table, which extends inland due to salinity intrusion. We suggest coupling ecological and hydrologic processes as a framework for future studies.

Checklists of Crustacea Decapoda from the Canary and Cape Verde Islands, with an assessment of Macaronesian and Cape Verde biogeographic marine ecoregions.

Science.gov (United States)

GonzÁlez, JosÉ A

2018-04-23

The complete list of Canarian marine decapods (last update by González Quiles 2003, popular book) currently comprises 374 species/subspecies, grouped in 198 genera and 82 families; whereas the Cape Verdean marine decapods (now fully listed for the first time) are represented by 343 species/subspecies with 201 genera and 80 families. Due to changing environmental conditions, in the last decades many subtropical/tropical taxa have reached the coasts of the Canary Islands. Comparing the carcinofaunal composition and their biogeographic components between the Canary and Cape Verde archipelagos would aid in: validating the appropriateness in separating both archipelagos into different ecoregions (Spalding et al. 2007), and understanding faunal movements between areas of benthic habitat. The consistency of both ecoregions is here compared and validated by assembling their decapod crustacean checklists, analysing their taxa composition, gathering their bathymetric data, and comparing their biogeographic patterns. Four main evidences (i.e. different taxa; divergent taxa composition; different composition of biogeographic patterns; different endemicity rates) support that separation, especially in coastal benthic decapods; and these parametres combined would be used as a valuable tool at comparing biotas from oceanic archipelagos. To understand/predict south-north faunal movements in a scenario of regional tropicalization, special attention is paid to species having at the Canaries their southernmost occurrence, and also to tropical African warm-affinity species.

Distributional patterns of the South American species of Hyalella (Amphipoda: Hyalellidae)

OpenAIRE

De los Ríos-Escalante, Patricio; Morrone, Juan J; Rivera, Reinaldo

2012-01-01

Distributional patterns of the South American species of the freshwater amphipod genus Hyalella were analysed using a panbiogeographic approach. Five generalized tracks were found: (1) northern Andes to Lake Titicaca (H. dielaii, H. meinerti, H. dybowskii, H.jelskii, H. lubominsky, and H. pauperocavae; (2) lake Titicaca (H. armata, H. cuprea, H. latinamus, H. lucifugax, H. montforti, H. neveulemairei, H. robusta, H. tiwanaku, H. simplex simplex, and H. solida); (3) central Andes (H. fossamanc...

Potential impacts of alien freshwater crayfish in South Africa | de ...

African Journals Online (AJOL)

The habitat preferences and life history characteristics of four alien species of freshwater crayfish (Cherax tenuimanus, C. destructor, C. quadricarinatus and Procambarus clarkii) are reviewed. The potential impact of these species on South African freshwater ecosystems is assessed and the desirability of allowing their ...

Snail abundance in freshwater canals in the eastern province of ...

African Journals Online (AJOL)

Ksu-network

2012-07-19

Jul 19, 2012 ... Recent Advances in Freshwater Biology. New Delhi. Anmol. Publication. Vol. 2. pp. 187-202. Al-Akel and Suliman. 12261. Supian Z, Ikhwanuddin AM (2002). Population dynamics of freshwater mollusks (Gastropod: Melanoides Tuberculatus) in crocker range park, Sabah. ASEAN Rev. Biodiv. Environ.

A Search for Freshwater in the Saline Aquifers of Coastal Bangladesh

Science.gov (United States)

Peters, C.; Hornberger, G. M.

2017-12-01

Can we locate pockets of freshwater amidst brackish groundwater in remote villages in Bangladesh? This study explores what we can infer about local groundwater-surface water (GW-SW) interactions in the polders of coastal Bangladesh. In this underdeveloped region, the shallow groundwater is primarily brackish with unpredictable apportioning of freshwater pockets. We use transects of piezometers, cores, electromagnetic induction, and water chemistry surveys to explore two sources of potential fresh groundwater: (1) tidal channel-aquifer exchange and (2) meteoric recharge. Freshwater is difficult to find due to disparate subsurface lithology, asymmetrical tidal dynamics, extreme seasonal fluctuations in rainfall, and limited field data. Observations suggest substantial lateral variability in shallow subsurface conductivity profiles as well as tidal pressure signals in piezometers. Nevertheless, active exchange of freshwater may be limited due to low permeability of banks and surface sediments limits. Small scale heterogeneity in delta formation likely caused much of the groundwater salinity variation. Without adequate ground truthing of groundwater quality, the ability to deduce the exact location of freshwater pockets may be restricted.

Multiple invasions into freshwater by pufferfishes (teleostei: tetraodontidae: a mitogenomic perspective.

Directory of Open Access Journals (Sweden)

Yusuke Yamanoue

Full Text Available Pufferfishes of the Family Tetraodontidae are the most speciose group in the Order Tetraodontiformes and mainly inhabit coastal waters along continents. Although no members of other tetraodontiform families have fully discarded their marine lives, approximately 30 tetraodontid species spend their entire lives in freshwaters in disjunct tropical regions of South America, Central Africa, and Southeast Asia. To investigate the interrelationships of tetraodontid pufferfishes and thereby elucidate the evolutionary origins of their freshwater habitats, we performed phylogenetic analysis based on whole mitochondrial genome sequences from 50 tetraodontid species and closely related species (including 31 newly determined sequences. The resulting phylogenies reveal that the family is composed of four major lineages and that freshwater species from the different continents are independently nested in two of the four lineages. A monophyletic origin of the use of freshwater habitats was statistically rejected, and ancestral habitat reconstruction on the resulting tree demonstrates that tetraodontids independently entered freshwater habitats in different continents at least three times. Relaxed molecular-clock Bayesian divergence time estimation suggests that the timing of these invasions differs between continents, occurring at 0-10 million years ago (MA in South America, 17-38 MA in Central Africa, and 48-78 MA in Southeast Asia. These timings are congruent with geological events that could facilitate adaptation to freshwater habitats in each continent.

Turtles: Freshwater

Science.gov (United States)

Gibbons, J. Whitfield; Lovich, Jeffrey E.; Bowden, R.M.

2017-01-01

With their iconic shells, turtles are morphologically distinct in being the only extant or extinct vertebrate animals to have their shoulders and hips inside their rib cages. By the time an asteroid hit the earth 65.5 million years ago, causing the extinction of dinosaurs, turtles were already an ancient lineage that was 70% through their evolutionary history to date. The remarkable evolutionary success of turtles over 220 million years is due to a combination of both conservative and effective life history traits and an essentially unchanging morphology that withstood the test of time. However, the life history traits of many species make them particularly susceptible to overharvest and habitat destruction in the modern world, and a majority of the world’s species face serious conservation challenges with several extinctions documented in modern times. The global plight of turtles is underscored by the fact that the percentage of imperiled species exceeds that of even the critically endangered primates.Freshwater turtles, with over 260 recognized species, have become a focus on a worldwide scale for many conservation issues. This article is a synthesis of a diverse body of information on the general biology of freshwater turtles, with particular emphasis on the extensive research on ecology, life history, and behavior that has been accomplished in the last half century. Much of the research has been applicable to the aforementioned conservation challenges. The studies presented include a combination of laboratory and field experiments and observational studies on this intriguing group of animals.

Draft genome of the American Eel (Anguilla rostrata).

Science.gov (United States)

Pavey, Scott A; Laporte, Martin; Normandeau, Eric; Gaudin, Jérémy; Letourneau, Louis; Boisvert, Sébastien; Corbeil, Jacques; Audet, Céline; Bernatchez, Louis

2017-07-01

Freshwater eels (Anguilla sp.) have large economic, cultural, ecological and aesthetic importance worldwide, but they suffered more than 90% decline in global stocks over the past few decades. Proper genetic resources, such as sequenced, assembled and annotated genomes, are essential to help plan sustainable recoveries by identifying physiological, biochemical and genetic mechanisms that caused the declines or that may lead to recoveries. Here, we present the first sequenced genome of the American eel. This genome contained 305 043 contigs (N50 = 7397) and 79 209 scaffolds (N50 = 86 641) for a total size of 1.41 Gb, which is in the middle of the range of previous estimations for this species. In addition, protein-coding regions, including introns and flanking regions, are very well represented in the genome, as 95.2% of the 458 core eukaryotic genes and 98.8% of the 248 ultra-conserved subset were represented in the assembly and a total of 26 564 genes were annotated for future functional genomics studies. We performed a candidate gene analysis to compare three genes among all three freshwater eel species and, congruent with the phylogenetic relationships, Japanese eel (A. japanica) exhibited the most divergence. Overall, the sequenced genome presented in this study is a crucial addition to the presently available genetic tools to help guide future conservation efforts of freshwater eels. © 2016 John Wiley & Sons Ltd.

Invasive alien freshwater fishes in the Wilderness Lakes System, a ...

African Journals Online (AJOL)

Invasive alien freshwater fishes in the Wilderness Lakes System, a wetland of international importance in the Western Cape Province, South Africa. ... A total of 87 893 fish comprising 16 species were caught. In addition to confirming the ... Key words: freshwater fish, invasive alien fishes, estuary, RAMSAR site, diversity.

Atmospheric teleconnection influence on North American land surface phenology

Science.gov (United States)

Dannenberg, Matthew P.; Wise, Erika K.; Janko, Mark; Hwang, Taehee; Kolby Smith, W.

2018-03-01

Short-term forecasts of vegetation activity are currently not well constrained due largely to our lack of understanding of coupled climate-vegetation dynamics mediated by complex interactions between atmospheric teleconnection patterns. Using ecoregion-scale estimates of North American vegetation activity inferred from remote sensing (1982-2015), we examined seasonal and spatial relationships between land surface phenology and the atmospheric components of five teleconnection patterns over the tropical Pacific, north Pacific, and north Atlantic. Using a set of regression experiments, we also tested for interactions among these teleconnection patterns and assessed predictability of vegetation activity solely based on knowledge of atmospheric teleconnection indices. Autumn-to-winter composites of the Southern Oscillation Index (SOI) were strongly correlated with start of growing season timing, especially in the Pacific Northwest. The two leading modes of north Pacific variability (the Pacific-North American, PNA, and West Pacific patterns) were significantly correlated with start of growing season timing across much of southern Canada and the upper Great Lakes. Regression models based on these Pacific teleconnections were skillful predictors of spring phenology across an east-west swath of temperate and boreal North America, between 40°N-60°N. While the North Atlantic Oscillation (NAO) was not strongly correlated with start of growing season timing on its own, we found compelling evidence of widespread NAO-SOI and NAO-PNA interaction effects. These results suggest that knowledge of atmospheric conditions over the Pacific and Atlantic Oceans increases the predictability of North American spring phenology. A more robust consideration of the complexity of the atmospheric circulation system, including interactions across multiple ocean basins, is an important step towards accurate forecasts of vegetation activity.

Changes of freshwater-lens thickness in basaltic island aquifers overlain by thick coastal sediments

Science.gov (United States)

Rotzoll, Kolja; Oki, Delwyn S.; El-Kadi, Aly I.

2010-01-01

Freshwater-lens thickness and long-term changes in freshwater volume in coastal aquifers are commonly assessed through repeated measurement of salinity profiles from monitor wells that penetrate into underlying salt water. In Hawaii, the thickest measured freshwater lens is currently 262 m in dike-free, volcanic-rock aquifers that are overlain by thick coastal sediments. The midpoint depth (depth where salinity is 50% salt water) between freshwater and salt water can serve as an indicator for freshwater thickness. Most measured midpoints have risen over the past 40 years, indicating a shrinking lens. The mean rate of rise of the midpoint from 1999–2009 varied locally, with faster rates in highly developed areas (1.0 m/year) and slower rates in less developed areas (0.5 m/year). The thinning of the freshwater lenses is the result of long-term groundwater withdrawal and reduced recharge. Freshwater/salt-water interface locations predicted from measured water levels and the Ghyben-Herzberg principle may be deeper than measured midpoints during some periods and shallower during other periods, although depths may differ up to 100 m in some cases. Moreover, changes in the midpoint are slower than changes in water level. Thus, water levels may not be a reliable indicator of the amount of freshwater in a coastal aquifer.

Multiple drivers of decline in the global status of freshwater crayfish (Decapoda:Astacidea)

Science.gov (United States)

Nadia I. Richman; Monika Böhm; Susan B. Adams; Fernando Alvarez; Elizabeth A. Bergey; John J. S. Bunn; Quinton Burnham; Jay Cordeiro; Jason Coughran; Keith A. Crandall; Kathryn L. Dawkins; Robert J. DiStefano; Niall E. Doran; Lennart Edsman; Arnold G. Eversole; Leopold Füreder; James M. Furse; Francesca Gherardi; Premek Hamr; David M. Holdich; Pierre Horwitz; Kerrylyn Johnston; Clive M. Jones; Julia P. G. Jones; Robert L. Jones; Thomas G. Jones; Tadashi Kawai; Susan Lawler; Marilu López-Mejía; Rebecca M. Miller; Carlos Pedraza-Lara; Julian D. Reynolds; Alastair M. M. Richardson; Mark B. Schultz; Guenter A. Schuster; Peter J. Sibley; Catherine Souty-Grosset; Christopher A. Taylor; Roger F. Thoma; Jerry Walls; Todd S. Walsh; Ben Cohen

2015-01-01

Rates of biodiversity loss are higher in freshwater ecosystems than in most terrestrial or marine ecosystems, making freshwater conservation a priority. However, prioritization methods are impeded by insufficient knowledge on the distribution and conservation status of freshwater taxa, particularly invertebrates. We evaluated the extinction risk of the world’s 590...

Identifying national freshwater ecosystem priority areas

CSIR Research Space (South Africa)

Nel, JL

2012-10-01

Full Text Available This presentation highlights the use of systematic conservation planning to identify priority areas for managing the health of freshwater ecosystems and their associated biodiversity and ecosystem services....

Extensive behavioural divergence following colonisation of the freshwater environment in threespine sticklebacks.

Directory of Open Access Journals (Sweden)

Carole Di-Poi

Full Text Available Colonisation of novel environments means facing new ecological challenges often resulting in the evolution of striking divergence in phenotypes. However, little is known about behavioural divergence following colonisation, despite the predicted importance of the role of behavioural phenotype-environment associations in adaptive divergence. We studied the threespine stickleback (Gasterosteus aculeatus, a model system for postglacial colonisation of freshwater habitats largely differing in ecological conditions from the ones faced by the descendants of the marine ancestor. We found that common-environment reared freshwater juveniles were less social, more active and more aggressive than their marine counterparts. This behavioural divergence could represent the result of natural selection that acted on individuals following freshwater colonisation, with predation as a key selection agent. Alternatively, the behavioural profile of freshwater juveniles could represent the characteristics of individuals that preferentially invaded freshwater after the glacial retreat, drawn from the standing variation present in the marine population.

Occurrence of digenean larvae in freshwater snails in the Ruvu ...

African Journals Online (AJOL)

Occurrence of digenean larvae in freshwater snails in the Ruvu basin, Tanzania. G Nkwengulila, ESP Kigadye. Abstract. A survey was carried out on digenean larvae infecting freshwater snails in five habitats in Dar es Salaam, Ruvu and Morogoro. 9424 snails belonging to 12 species from five families were examined for ...

Short Communications: First record of freshwater fish on the Cape ...

African Journals Online (AJOL)

During a non-exhaustive survey of freshwater bodies on five islands of the archipelago, the first presence of a freshwater fish was recorded. Using barcoding sequences, the species was identified as the guppy (Poecilia reticulata), a highly invasive species alien to the Cape Verdean Islands. Key words: Cape Verde, guppy, ...

2H and 18O Freshwater Isoscapes of Scotland

Science.gov (United States)

Meier-Augenstein, Wolfram; Hoogewerff, Jurian; Kemp, Helen; Frew, Danny

2013-04-01

Scotland's freshwater lochs and reservoirs provide a vital resource for sustaining biodiversity, agriculture, food production as well as for human consumption. Regular monitoring of freshwaters by the Scottish Environment Protection Agency (SEPA) fulfils legislative requirements with regards to water quality but new scientific methods involving stable isotope analysis present an opportunity combining these mandatory monitoring schemes with fundamental research to inform and deliver on current and nascent government policies [1] through gaining a greater understanding of Scottish waters and their importance in the context of climate change, environmental sustainability and food security. For example, 2H and 18O isoscapes of Scottish freshwater could be used to underpin research and its applications in: • Climate change - Using longitudinal changes in the characteristic isotope composition of freshwater lochs and reservoirs as proxy, isoscapes will provide a means to assess if and how changes in temperature and weather patterns might impact on precipitation patterns and amount. • Scottish branding - Location specific stable isotope signatures of Scottish freshwater have the potential to be used as a tool for provenancing and thus protecting premium Scottish produce such as Scottish beef, Scottish soft fruit and Scottish Whisky. During 2011 and 2012, with the support of SEPA more than 110 samples from freshwater lochs and reservoirs were collected from 127 different locations across Scotland including the Highlands and Islands. Here we present the results of this sampling and analysis exercise isotope analyses in form of 2H and 18O isoscapes with an unprecedented grid resolution of 26.5 × 26.5 km (or 16.4 × 16.4 miles). [1] Adaptation Framework - Adapting Our Ways: Managing Scotland's Climate Risk (2009): Scotland's Biodiversity: It's in Your Hands - A strategy for the conservation and enhancement of biodiversity in Scotland (2005); Recipe For Success - Scotland

Non-parallel divergence across freshwater and marine three-spined stickleback Gasterosteus aculeatus populations.

Science.gov (United States)

Pujolar, J M; Ferchaud, A L; Bekkevold, D; Hansen, M M

2017-07-01

This work investigated whether multiple freshwater populations of three-spined stickleback Gasterosteus aculeatus in different freshwater catchments in the Jutland Peninsula, Denmark, derived from the same marine populations show repeated adaptive responses. A total of 327 G. aculeatus collected at 13 sampling locations were screened for genetic variation using a combination of 70 genes putatively under selection and 26 neutral genes along with a marker linked to the ectodysplasin gene (eda), which is strongly correlated with plate armour morphs in the species. A highly significant genetic differentiation was found that was higher among different freshwater samples than between marine-freshwater samples. Tests for selection between marine and freshwater populations showed a very low degree of parallelism and no single nucleotide polymorphism was detected as outlier in all freshwater-marine pairwise comparisons, including the eda. This suggests that G. aculeatus is not necessarily the prime example of parallel local adaptation suggested in much of the literature and that important exceptions exist (i.e. the Jutland Peninsula). While marine populations in the results described here showed a high phenotype-genotype correlation at eda, a low association was found for most of the freshwater populations. The most extreme case was found in the freshwater Lake Hald where all low-plated phenotypes were either homozygotes for the allele supposed to be associated with completely plated morphs or heterozygotes, but none were homozygotes for the putative low-plated allele. Re-examination of data from seven G. aculeatus studies agrees in showing a high but partial association between phenotype-genotype at eda in G. aculeatus freshwater populations and that mismatches occur everywhere in the European regions studied (higher in some areas, i.e. Denmark). This is independent of the eda marker used. © 2017 The Fisheries Society of the British Isles.

Sources, variability and fate of freshwater in the Bellingshausen Sea, Antarctica

Science.gov (United States)

Regan, Heather C.; Holland, Paul R.; Meredith, Michael P.; Pike, Jennifer

2018-03-01

During the second half of the twentieth century, the Antarctic Peninsula was subjected to a rapid increase in air temperatures. This was accompanied by a reduction in sea ice extent, increased precipitation and a dramatic retreat of glaciers associated with an increase in heat flux from deep ocean water masses. Isotopic tracers have been used previously to investigate the relative importance of the different freshwater sources to the adjacent Bellingshausen Sea (BS), but the data coverage is strongly biased toward summer. Here we use a regional model to investigate the ocean's response to the observed changes in its different freshwater inputs (sea ice melt/freeze, precipitation, evaporation, iceberg/glacier melt, and ice shelf melt). The model successfully recreates BS water masses and performs well against available freshwater data. By tracing the sources and pathways of the individual components of the freshwater budget, we find that sea ice dominates seasonal changes in the total freshwater content and flux, but all sources make a comparable contribution to the annual-mean. Interannual variability is dominated by sea ice and precipitation. Decadal trends in the salinity and stratification of the ocean are investigated, and a 20-year surface freshening from 1992 to 2011 is found to be predominantly driven by decreasing autumn sea ice growth. These findings will help to elucidate the role of freshwater in driving circulation and water column structure changes in this climatically-sensitive region.

Effects of pollution on freshwater fish

International Nuclear Information System (INIS)

McKim, J.M.; Anderson, R.L.; Benoit, D.A.; Spehar, R.L.; Stokes, G.N.

1976-01-01

Studies of the effects of pollution on freshwater fish are reviewed. Subjects include: inorganic industrial pollutants, man-made disturbances and radioactive pollutants. Topics include uptake distribution, retention, mortality, and lethal doses

The Implications of Ranaviruses to European farmed and wild freshwater fish

DEFF Research Database (Denmark)

Jensen, Ann Britt Bang

The present thesis explores the implications of ranaviruses to European farmed and wild freshwater fish. The work presented was carried out as a part of the EU project “Risk assessment of new and emerging systemic iridoviral diseases for European fish and aquatic ecosystems” which was initiated...... in 2005 as a reaction to the speculation that ranaviruses might pose a serious threat to both farmed and wild-living freshwater fish and amphibians within the European community. In the present thesis, the purpose is to determine the implications of ranaviruses to European freshwater farmed and wild......-living fish. The following specific objectives are addressed: Objective 1: To determine the susceptibility of selected European freshwater fish to a panel of ranaviruses Objective 2: To determine whether ornamental fish are susceptible to or can be carriers of ranaviruses Objective 3: To develop a model...

Successful enrichment of the ubiquitous freshwater acI Actinobacteria.

Science.gov (United States)

Garcia, Sarahi L; McMahon, Katherine D; Grossart, Hans-Peter; Warnecke, Falk

2014-02-01

Actinobacteria of the acI lineage are often the numerically dominant bacterial phylum in surface freshwaters, where they can account for > 50% of total bacteria. Despite their abundance, there are no described isolates. In an effort to obtain enrichment of these ubiquitous freshwater Actinobacteria, diluted freshwater samples from Lake Grosse Fuchskuhle, Germany, were incubated in 96-well culture plates. With this method, a successful enrichment containing high abundances of a member of the lineage acI was established. Phylogenetic classification showed that the acI Actinobacteria of the enrichment belonged to the acI-B2 tribe, which seems to prefer acidic lakes. This enrichment grows to low cell densities and thus the oligotrophic nature of acI-B2 was confirmed. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Reversing a tree regeneration crisis in an endangered ecoregion.

Science.gov (United States)

Fischer, Joern; Stott, Jenny; Zerger, Andre; Warren, Garth; Sherren, Kate; Forrester, Robert I

2009-06-23

Global food demand is growing rapidly. Livestock grazing can provide a valuable source of protein, but conventional grazing is often unsustainable. We studied an 800,000-ha section of a threatened ecoregion in southeastern Australia. Conventional management in the region involves continuous livestock grazing with few rest periods and regular fertilizer application. By using remotely sensed data on tree cover and extensive field data on livestock grazing regimes, soil chemistry, tree diameters, and tree regeneration, we show that the region is facing a tree regeneration crisis. Under conventional management, across the region, millions of hectares of land currently supporting tens of millions of trees will be treeless within decades from now. This would have severe negative ramifications for biodiversity and key ecosystem services, including water infiltration and shade provision for livestock. However, we identified an unexpected win-win solution for tree regeneration and commercial grazing. A relatively new practice in the region is fast-rotational grazing, characterized by prolonged rest periods in between short, intensive grazing events. The probability of regeneration under fast-rotational grazing was up to 4-fold higher than under conventional grazing, and it did not differ significantly from the probability of regeneration in ungrazed areas. In addition, trees were more likely to regenerate where soil nutrient levels were low. These findings suggest that the tree regeneration crisis can be reversed by applying low-input, fast-rotational grazing. New policy settings supporting these practices could signal a turning point for the region, from ecological decline to ecological recovery.

Assessing and managing freshwater ecosystems vulnerable to global change

Science.gov (United States)

Angeler, David G.; Allen, Craig R.; Birge, Hannah E.; Drakare, Stina; McKie, Brendan G.; Johnson, Richard K.

2014-01-01

Freshwater ecosystems are important for global biodiversity and provide essential ecosystem services. There is consensus in the scientific literature that freshwater ecosystems are vulnerable to the impacts of environmental change, which may trigger irreversible regime shifts upon which biodiversity and ecosystem services may be lost. There are profound uncertainties regarding the management and assessment of the vulnerability of freshwater ecosystems to environmental change. Quantitative approaches are needed to reduce this uncertainty. We describe available statistical and modeling approaches along with case studies that demonstrate how resilience theory can be applied to aid decision-making in natural resources management. We highlight especially how long-term monitoring efforts combined with ecological theory can provide a novel nexus between ecological impact assessment and management, and the quantification of systemic vulnerability and thus the resilience of ecosystems to environmental change.

Impact of increasing antarctic glacial freshwater release on regional sea-ice cover in the Southern Ocean

Science.gov (United States)

Merino, Nacho; Jourdain, Nicolas C.; Le Sommer, Julien; Goosse, Hugues; Mathiot, Pierre; Durand, Gael

2018-01-01

The sensitivity of Antarctic sea-ice to increasing glacial freshwater release into the Southern Ocean is studied in a series of 31-year ocean/sea-ice/iceberg model simulations. Glaciological estimates of ice-shelf melting and iceberg calving are used to better constrain the spatial distribution and magnitude of freshwater forcing around Antarctica. Two scenarios of glacial freshwater forcing have been designed to account for a decadal perturbation in glacial freshwater release to the Southern Ocean. For the first time, this perturbation explicitly takes into consideration the spatial distribution of changes in the volume of Antarctic ice shelves, which is found to be a key component of changes in freshwater release. In addition, glacial freshwater-induced changes in sea ice are compared to typical changes induced by the decadal evolution of atmospheric states. Our results show that, in general, the increase in glacial freshwater release increases Antarctic sea ice extent. But the response is opposite in some regions like the coastal Amundsen Sea, implying that distinct physical mechanisms are involved in the response. We also show that changes in freshwater forcing may induce large changes in sea-ice thickness, explaining about one half of the total change due to the combination of atmospheric and freshwater changes. The regional contrasts in our results suggest a need for improving the representation of freshwater sources and their evolution in climate models.

Biota: Providing often-overlooked connections among freshwater systems

Science.gov (United States)

Mushet, David M.; Christensen, Jay R.; Bennett, Michah; Alexander, Laurie C.

2017-01-01

When we think about connections in and among aquatic systems, we typically envision clear headwater streams flowing into downstream rivers, river floodwaters spilling out onto adjacent floodplains, or groundwater connecting wetlands to lakes and streams. However, there is another layer of connectivity moving materials among freshwater systems, one with connections that are not always tied to downgradient flows of surface waters and groundwater. These movements are those of organisms, key components of virtually every freshwater system on the planet. In their movements across the landscape, biota connect aquatic systems in often-overlooked ways.

78 FR 52192 - Final Aquatic Life Ambient Water Quality Criteria For Ammonia-Freshwater 2013

Science.gov (United States)

2013-08-22

... ambient water quality criteria for the protection of aquatic life from effects of ammonia in freshwater... ammonia to freshwater aquatic life. On December 30, 2009, EPA published draft national recommended water... freshwater are intended to protect aquatic life and do not address human health toxicity data. The water...

Key roles for freshwater Actinobacteria revealed by deep metagenomic sequencing.

Science.gov (United States)

Ghai, Rohit; Mizuno, Carolina Megumi; Picazo, Antonio; Camacho, Antonio; Rodriguez-Valera, Francisco

2014-12-01

Freshwater ecosystems are critical but fragile environments directly affecting society and its welfare. However, our understanding of genuinely freshwater microbial communities, constrained by our capacity to manipulate its prokaryotic participants in axenic cultures, remains very rudimentary. Even the most abundant components, freshwater Actinobacteria, remain largely unknown. Here, applying deep metagenomic sequencing to the microbial community of a freshwater reservoir, we were able to circumvent this traditional bottleneck and reconstruct de novo seven distinct streamlined actinobacterial genomes. These genomes represent three new groups of photoheterotrophic, planktonic Actinobacteria. We describe for the first time genomes of two novel clades, acMicro (Micrococcineae, related to Luna2,) and acAMD (Actinomycetales, related to acTH1). Besides, an aggregate of contigs belonged to a new branch of the Acidimicrobiales. All are estimated to have small genomes (approximately 1.2 Mb), and their GC content varied from 40 to 61%. One of the Micrococcineae genomes encodes a proteorhodopsin, a rhodopsin type reported for the first time in Actinobacteria. The remarkable potential capacity of some of these genomes to transform recalcitrant plant detrital material, particularly lignin-derived compounds, suggests close linkages between the terrestrial and aquatic realms. Moreover, abundances of Actinobacteria correlate inversely to those of Cyanobacteria that are responsible for prolonged and frequently irretrievable damage to freshwater ecosystems. This suggests that they might serve as sentinels of impending ecological catastrophes. © 2014 John Wiley & Sons Ltd.

Oil spills into freshwater environments-literature review of fate and effects

International Nuclear Information System (INIS)

Taylor, E.; Owens, E.; Craig, A.; Steen, A.; Fritz, D.

1993-01-01

A literature search (1984--1992) was performed to summarize the environmental and human health effects of inlands spills. Over 100 major spills that affected freshwater environments were reported through the Emergency Response Notification System (ERNS) in 1991--1992 alone. Spills from pipelines outnumber all other sources combined. The oil types involved are about equally distributed between non-persistent oils and crude. Small rivers, streams, and creeks are the habitats into which most freshwater spills occur. Cleanup of stranded oil, rather than protection or recovery of floating oil, is the norm in most situations because stranding on river and lake banks often occurs before response is possible. The prediction of spill movement commonly is simpler for freshwater spills because freshwater bodies are relatively small and commonly have strong uni-directional flow; however, fast flow in rivers and streams and turnover in cooling lakes serve to distribute oil throughout the water column. Impacts to the environment, through food web structures or groundwater, may persist for months following a spill but seldom persist for years, unlike marine coastal impacts. Chronic impacts of oil spills into freshwater are rarely documented and these impacts are difficult to separate from effects of other hydrocarbons in the environment

Life history and biogeographic diversification of an endemic western North American freshwater fish clade using a comparative species tree approach.

Science.gov (United States)

Baumsteiger, Jason; Kinziger, Andrew P; Aguilar, Andres

2012-12-01

The west coast of North America contains a number of biogeographic freshwater provinces which reflect an ever-changing aquatic landscape. Clues to understanding this complex structure are often encapsulated genetically in the ichthyofauna, though frequently as unresolved evolutionary relationships and putative cryptic species. Advances in molecular phylogenetics through species tree analyses now allow for improved exploration of these relationships. Using a comprehensive approach, we analyzed two mitochondrial and nine nuclear loci for a group of endemic freshwater fish (sculpin-Cottus) known for a wide ranging distribution and complex species structure in this region. Species delimitation techniques identified three novel cryptic lineages, all well supported by phylogenetic analyses. Comparative phylogenetic analyses consistently found five distinct clades reflecting a number of unique biogeographic provinces. Some internal node relationships varied by species tree reconstruction method, and were associated with either Bayesian or maximum likelihood statistical approaches or between mitochondrial, nuclear, and combined datasets. Limited cases of mitochondrial capture were also evident, suggestive of putative ancestral hybridization between species. Biogeographic diversification was associated with four major regions and revealed historical faunal exchanges across regions. Mapping of an important life-history character (amphidromy) revealed two separate instances of trait evolution, a transition that has occurred repeatedly in Cottus. This study demonstrates the power of current phylogenetic methods, the need for a comprehensive phylogenetic approach, and the potential for sculpin to serve as an indicator of biogeographic history for native ichthyofauna in the region. Copyright © 2012 Elsevier Inc. All rights reserved.

Homogenization patterns of the world's freshwater fish faunas.

Science.gov (United States)

Villéger, Sébastien; Blanchet, Simon; Beauchard, Olivier; Oberdorff, Thierry; Brosse, Sébastien

2011-11-01

The world is currently undergoing an unprecedented decline in biodiversity, which is mainly attributable to human activities. For instance, nonnative species introduction, combined with the extirpation of native species, affects biodiversity patterns, notably by increasing the similarity among species assemblages. This biodiversity change, called taxonomic homogenization, has rarely been assessed at the world scale. Here, we fill this gap by assessing the current homogenization status of one of the most diverse vertebrate groups (i.e., freshwater fishes) at global and regional scales. We demonstrate that current homogenization of the freshwater fish faunas is still low at the world scale (0.5%) but reaches substantial levels (up to 10%) in some highly invaded river basins from the Nearctic and Palearctic realms. In these realms experiencing high changes, nonnative species introductions rather than native species extirpations drive taxonomic homogenization. Our results suggest that the "Homogocene era" is not yet the case for freshwater fish fauna at the worldwide scale. However, the distressingly high level of homogenization noted for some biogeographical realms stresses the need for further understanding of the ecological consequences of homogenization processes.

Predator-induced reduction of freshwater carbon dioxide emissions

Science.gov (United States)

Atwood, Trisha B.; Hammill, Edd; Greig, Hamish S.; Kratina, Pavel; Shurin, Jonathan B.; Srivastava, Diane S.; Richardson, John S.

2013-03-01

Predators can influence the exchange of carbon dioxide between ecosystems and the atmosphere by altering ecosystem processes such as decomposition and primary production, according to food web theory. Empirical knowledge of such an effect in freshwater systems is limited, but it has been suggested that predators in odd-numbered food chains suppress freshwater carbon dioxide emissions, and predators in even-numbered food chains enhance emissions. Here, we report experiments in three-tier food chains in experimental ponds, streams and bromeliads in Canada and Costa Rica in the presence or absence of fish (Gasterosteus aculeatus) and invertebrate (Hesperoperla pacifica and Mecistogaster modesta) predators. We monitored carbon dioxide fluxes along with prey and primary producer biomass. We found substantially reduced carbon dioxide emissions in the presence of predators in all systems, despite differences in predator type, hydrology, climatic region, ecological zone and level of in situ primary production. We also observed lower amounts of prey biomass and higher amounts of algal and detrital biomass in the presence of predators. We conclude that predators have the potential to markedly influence carbon dioxide dynamics in freshwater systems.

Freshwater availability and coastal wetland foundation species: ecological transitions along a rainfall gradient

Science.gov (United States)

Osland, Michael J.; Enwright, Nicholas M.; Stagg, Camille L.

2014-01-01

Climate gradient-focused ecological research can provide a foundation for better understanding critical ecological transition points and nonlinear climate-ecological relationships, which is information that can be used to better understand, predict, and manage ecological responses to climate change. In this study, we examined the influence of freshwater availability upon the coverage of foundation plant species in coastal wetlands along a northwestern Gulf of Mexico rainfall gradient. Our research addresses the following three questions: (1) what are the region-scale relationships between measures of freshwater availability (e.g., rainfall, aridity, freshwater inflow, salinity) and the relative abundance of foundation plant species in tidal wetlands; (2) How vulnerable are foundation plant species in tidal wetlands to future changes in freshwater availability; and (3) What is the potential future relative abundance of tidal wetland foundation plant species under alternative climate change scenarios? We developed simple freshwater availability-based models to predict the relative abundance (i.e., coverage) of tidal wetland foundation plant species using climate data (1970-2000), estuarine freshwater inflow-focused data, and coastal wetland habitat data. Our results identify regional ecological thresholds and nonlinear relationships between measures of freshwater availability and the relative abundance of foundation plant species in tidal wetlands. In drier coastal zones, relatively small changes in rainfall could produce comparatively large landscape-scale changes in foundation plant species abundance which would affect some ecosystem good and services. Whereas a drier future would result in a decrease in the coverage of foundation plant species, a wetter future would result in an increase in foundation plant species coverage. In many ways, the freshwater-dependent coastal wetland ecological transitions we observed are analogous to those present in dryland

Selecting reliable and robust freshwater macroalgae for biomass applications.

Directory of Open Access Journals (Sweden)

Rebecca J Lawton

Full Text Available Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m⁻² day⁻¹, lowest ash content (3-8%, lowest water content (fresh weigh: dry weight ratio of 3.4, highest carbon content (45% and highest bioenergy potential (higher heating value 20 MJ/kg compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO₂ across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96% (±7 S.E. in Oedogonium-Spirogyra bi-cultures, 86% (±16 S.E. in Oedogonium-Cladophora bi-cultures and 82% (±18 S.E. in polycultures. The high productivity, bioenergy potential and competitive dominance of Oedogonium make this species an ideal freshwater macroalgal target for large-scale production and a valuable biomass source for bioenergy applications. These results demonstrate that freshwater macroalgae are thus far an under-utilised feedstock with

Radionuclide transfer to freshwater biota species: review of Russian language studies

International Nuclear Information System (INIS)

Fesenko, S.; Fesenko, J.; Sanzharova, N.; Karpenko, E.; Titov, I.

2011-01-01

Around 130 publications reporting studies on radionuclide transfer to freshwater biota species conducted in the former USSR were reviewed to provide the concentration ratio values. None of these studies were available up to now in the English language reviews or publications. The values derived have been compared with the CR values used for freshwater systems in the International reviews. For some radionuclides reviewed in this paper, the data are in good agreement with the mean CR values presented earlier, however for some of them, in particular, for 241 Am (bivalve molluscs, gastropods and pelagic fish), 60 Co (gastropods, benthic fish and insect larvae), 90 Sr and 137 Cs (benthic fish and zooplankton), the mean values given here are substantially different from those presented earlier. The data reported in this paper for thirty five radionuclides and eleven groups of freshwater species markedly improve the extent of available data for evaluation of radiation impact on freshwater species. - Research highlights: → The paper provides information on concentration ratios to freshwater biota species for 35 radionuclides. Many of the data are for 90 Sr and 137 Cs. → For the majority of radionuclides reviewed in this paper, the CR values are in good agreement with those given in the recent International reviews. → For 241 Am (bivalve molluscs, gastropods and pelagic fish), 60 Co (gastropods, benthic fish and insect larvae), 90 Sr and 137 Cs (benthic fish and zooplankton), the mean values based on review of the Russian language publications are substantially different from those presented in the International reviews. → Information presented in the paper significantly increases the availability of data on radionuclide accumulation in freshwater species.

Tributyltin-resistant bacteria from estuarine and freshwater sediments.

Science.gov (United States)

Wuertz, S; Miller, C E; Pfister, R M; Cooney, J J

1991-01-01

Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT selected for a TBT-resistant population. In contrast, EC50s were significantly lower for populations from a TBT-contaminated estuarine site than for those from a site without TBT, suggesting that other factors in addition to TBT determine whether populations become resistant. EC50s for populations from TBT-contaminated freshwater sediments were nearly 30 times higher than those for populations from TBT-contaminated estuarine sediments. We defined a TBT-resistant bacterium as one which grows on trypticase soy agar containing 8.4 microM TBT, a concentration which prevented the growth of 90% of the culturable bacteria from these sediments. The toxicity of TBT in laboratory media was influenced markedly by the composition of the medium and whether it was liquid or solid. Ten TBT-resistant isolates from estuarine sediments and 19 from freshwater sediments were identified to the genus level. Two isolates, each a Bacillus sp., may be the first gram-positive bacteria isolated from fresh water in the presence of a high concentration of TBT. There was a high incidence of resistance to heavy metals: metal resistance indices were 0.76 for estuarine isolates and 0.68 for freshwater isolates.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1746939

Egg masses of the Patagonian squid Doryteuthis (Amerigo gahi attached to giant kelp (Macrocystis pyrifera in the sub-Antarctic ecoregion

Directory of Open Access Journals (Sweden)

Sebastián Rosenfeld

2014-11-01

Full Text Available Egg masses of the Patagonian squid Doryteuthis (Amerigo gahi attached to giant kelp (Macrocystis pyrifera in the Magellanic channels of the sub-Antarctic ecoregion in southern South America is documented for the first time. Of seven egg masses observed between 2008 and 2011, one was taken to the laboratory to be analysed and photographed. Comprising long transparent capsules containing eggs, the masses were strongly attached to the stipes of M. pyrifera. This macroalgae is a potentially important economic resource due to its multiple industrial uses; this study shows that it also serves an important ecological role as a spawning substrate for D. gahi.

Analysis of the Arctic system for freshwater cycle intensification: Observations and expectations

Science.gov (United States)

Rawlins, M.A.; Steele, M.; Holland, M.M.; Adam, J.C.; Cherry, J.E.; Francis, J.A.; Groisman, P.Y.; Hinzman, L.D.; Huntington, T.G.; Kane, D.L.; Kimball, J.S.; Kwok, R.; Lammers, R.B.; Lee, C.M.; Lettenmaier, D.P.; McDonald, K.C.; Podest, E.; Pundsack, J.W.; Rudels, B.; Serreze, Mark C.; Shiklomanov, A.; Skagseth, O.; Troy, T.J.; Vorosmarty, C.J.; Wensnahan, M.; Wood, E.F.; Woodgate, R.; Yang, D.; Zhang, K.; Zhang, T.

2010-01-01

Hydrologic cycle intensification is an expected manifestation of a warming climate. Although positive trends in several global average quantities have been reported, no previous studies have documented broad intensification across elements of the Arctic freshwater cycle (FWC). In this study, the authors examine the character and quantitative significance of changes in annual precipitation, evapotranspiration, and river discharge across the terrestrial pan-Arctic over the past several decades from observations and a suite of coupled general circulation models (GCMs). Trends in freshwater flux and storage derived from observations across the Arctic Ocean and surrounding seas are also described. With few exceptions, precipitation, evapotranspiration, and river discharge fluxes from observations and the GCMs exhibit positive trends. Significant positive trends above the 90% confidence level, however, are not present for all of the observations. Greater confidence in the GCM trends arises through lower interannual variability relative to trend magnitude. Put another way, intrinsic variability in the observations tends to limit confidence in trend robustness. Ocean fluxes are less certain, primarily because of the lack of long-term observations. Where available, salinity and volume flux data suggest some decrease in saltwater inflow to the Barents Sea (i.e., a decrease in freshwater outflow) in recent decades. A decline in freshwater storage across the central Arctic Ocean and suggestions that large-scale circulation plays a dominant role in freshwater trends raise questions as to whether Arctic Ocean freshwater flows are intensifying. Although oceanic fluxes of freshwater are highly variable and consistent trends are difficult to verify, the other components of the Arctic FWC do show consistent positive trends over recent decades. The broad-scale increases provide evidence that the Arctic FWC is experiencing intensification. Efforts that aim to develop an adequate

Distribution and Modeled Transport of Plastic Pollution in the Great Lakes, the World's Largest Freshwater Resource

Directory of Open Access Journals (Sweden)

Rachel N. Cable

2017-07-01

Full Text Available Most plastic pollution originates on land. As such, freshwater bodies serve as conduits for the transport of plastic litter to the ocean. Understanding the concentrations and fluxes of plastic litter in freshwater ecosystems is critical to our understanding of the global plastic litter budget and underpins the success of future management strategies. We conducted a replicated field survey of surface plastic concentrations in four lakes in the North American Great Lakes system, the largest contiguous freshwater system on the planet. We then modeled plastic transport to resolve spatial and temporal variability of plastic distribution in one of the Great Lakes, Lake Erie. Triplicate surface samples were collected at 38 stations in mid-summer of 2014. Plastic particles >106 μm in size were quantified. Concentrations were highest near populated urban areas and their water infrastructure. In the highest concentration trawl, nearly 2 million fragments km−2 were found in the Detroit River—dwarfing previous reports of Great Lakes plastic abundances by over 4-fold. Yet, the accuracy of single trawl counts was challenged: within-station plastic abundances varied 0- to 3-fold between replicate trawls. In the smallest size class (106–1,000 μm, false positive rates of 12–24% were determined analytically for plastic vs. non-plastic, while false negative rates averaged ~18%. Though predicted to form in summer by the existing Lake Erie circulation model, our transport model did not predict a permanent surface “Lake Erie Garbage Patch” in its central basin—a trend supported by field survey data. Rather, general eastward transport with recirculation in the major basins was predicted. Further, modeled plastic residence times were drastically influenced by plastic buoyancy. Neutrally buoyant plastics—those with the same density as the ambient water—were flushed several times slower than plastics floating at the water's surface and exceeded the

Inactivation of Paragonimus westermani metacercariae in soy sauce-marinated and frozen freshwater crabs.

Science.gov (United States)

Kim, Tae Im; Oh, Se-Ra; Dai, Fuhong; Yang, Hyun-Jong; Ha, Sang-Do; Hong, Sung-Jong

2017-03-01

Soy sauce-marinated freshwater crabs (Eriocheir japonicus) are a source of human paragonimiasis. The viability of Paragonimus westermani metacercariae (PwMc) in marinated crabs was investigated in an experimental setting. The PwMc collected from freshwater crayfish were inoculated into freshwater crabs, which were then frozen or marinated in soy sauce. All PwMc in the freshwater crabs were inactivated after freezing for 48 h at -20 °C and after freezing for 12 h at -40 °C. After marinating for 32 days, the survival rate of PwMc in 5% NaCl soy sauce was 50%, in 7.5% NaCl soy sauce it was 33.3%, and in 10.0% NaCl soy sauce it was 31.3%. When marinated for 64 days, all PwMc were inactivated in all experimental groups. These results revealed that freezing and soy sauce marination were detrimental to the survival of PwMc in freshwater crabs. Specifically, freezing crabs for more than 48 h or soaking them in soy sauce containing at least 5.0% NaCl for 64 days can inactivate PwMc. These results can inform the production of the traditional Korean soy sauce-marinated freshwater crabs known as gejang.

Graphite Based Electrode for ECG Monitoring: Evaluation under Freshwater and Saltwater Conditions

Directory of Open Access Journals (Sweden)

Tharoeun Thap

2016-04-01

Full Text Available We proposed new electrodes that are applicable for electrocardiogram (ECG monitoring under freshwater- and saltwater-immersion conditions. Our proposed electrodes are made of graphite pencil lead (GPL, a general-purpose writing pencil. We have fabricated two types of electrode: a pencil lead solid type (PLS electrode and a pencil lead powder type (PLP electrode. In order to assess the qualities of the PLS and PLP electrodes, we compared their performance with that of a commercial Ag/AgCl electrode, under a total of seven different conditions: dry, freshwater immersion with/without movement, post-freshwater wet condition, saltwater immersion with/without movement, and post-saltwater wet condition. In both dry and post-freshwater wet conditions, all ECG-recorded PQRST waves were clearly discernible, with all types of electrodes, Ag/AgCl, PLS, and PLP. On the other hand, under the freshwater- and saltwater-immersion conditions with/without movement, as well as post-saltwater wet conditions, we found that the proposed PLS and PLP electrodes provided better ECG waveform quality, with significant statistical differences compared with the quality provided by Ag/AgCl electrodes.

The development of a GIS atlas of southern African freshwater fish ...

African Journals Online (AJOL)

The development of a GIS atlas of southern African freshwater fish. LEP Scott, PH Skelton, AJ Booth, L Verheust. Abstract. A geographic information systems (GIS) based atlas of southern African freshwater fish has been developed for the SADC countries. The JLB Smith Institute of Ichthyology, in collaboration with ALCOM, ...

Freshwater Ecosystem Service Flow Model To Evaluate Regional Water Security: A Case Study In Beijing-Tianjin-Hebei Region, China

Science.gov (United States)

Li, D.; Li, S.

2016-12-01

Freshwater service, as the most important support ecosystem service, is essential to human survival and development. Many studies have evidenced the spatial differences in the supply and demand of ecosystem services and raised the concept of ecosystem service flow. However, rather few studies quantitatively characterize the freshwater service flow. This paper aims to quantify the effect of freshwater ecosystem service flow on downstream areas in Beijing-Tianjin-Hebei (BTH) region, China over 2000, 2005 and 2010. We computed the freshwater ecosystem service provision with InVEST model. We calculated freshwater ecosystem service consumption with water quota method. We simulated the freshwater ecosystem service flow using our simplified flow model and assessed the regional water security with the improved freshwater security index. The freshwater provision service mainly depends on climatic factors that cannot be influenced by management, while the freshwater consumption service is constrained by human activities. Furthermore, the decrease of water quota for agricultural, domestic and industrial water counteracts the impact of increasing freshwater demand. The analysis of freshwater ecosystem service flow reveals that the majority area of the BTH (69.2%) is affected by upstream freshwater. If freshwater ecosystem service flow is considered, the water safety areas of the whole BTH account for 66.9%, 66.1%, 71.3%, which increase 6.4%, 6.8% and 5.7% in 2000, 2005 and 2010, respectively. These results highlight the need to understand the teleconnections between distant freshwater ecosystem service provision and local freshwater ecosystem service use. This approach therefore helps managers choose specific management and investment strategies for critical upstream freshwater provisions across different regions.

Patterns of Freshwater Species Richness, Endemism, and Vulnerability in California.

Directory of Open Access Journals (Sweden)

Jeanette K Howard

Full Text Available The ranges and abundances of species that depend on freshwater habitats are declining worldwide. Efforts to counteract those trends are often hampered by a lack of information about species distribution and conservation status and are often strongly biased toward a few well-studied groups. We identified the 3,906 vascular plants, macroinvertebrates, and vertebrates native to California, USA, that depend on fresh water for at least one stage of their life history. We evaluated the conservation status for these taxa using existing government and non-governmental organization assessments (e.g., endangered species act, NatureServe, created a spatial database of locality observations or distribution information from ~400 data sources, and mapped patterns of richness, endemism, and vulnerability. Although nearly half of all taxa with conservation status (n = 1,939 are vulnerable to extinction, only 114 (6% of those vulnerable taxa have a legal mandate for protection in the form of formal inclusion on a state or federal endangered species list. Endemic taxa are at greater risk than non-endemics, with 90% of the 927 endemic taxa vulnerable to extinction. Records with spatial data were available for a total of 2,276 species (61%. The patterns of species richness differ depending on the taxonomic group analyzed, but are similar across taxonomic level. No particular taxonomic group represents an umbrella for all species, but hotspots of high richness for listed species cover 40% of the hotspots for all other species and 58% of the hotspots for vulnerable freshwater species. By mapping freshwater species hotspots we show locations that represent the top priority for conservation action in the state. This study identifies opportunities to fill gaps in the evaluation of conservation status for freshwater taxa in California, to address the lack of occurrence information for nearly 40% of freshwater taxa and nearly 40% of watersheds in the state, and to

Education Agendas and Resistance with the Teaching and Learning of Freshwater and Extreme Freshwater Events

Science.gov (United States)

Sammel, Alison; McMartin, Dena; Arbuthnott, Katherine

2018-01-01

Despite the essentiality of freshwater to all life on the planet, the populous has inadequate understandings of water. Formal education plays a key role in shaping how individuals and communities make sense of water, its accessibility, management, consumption, and hazards. This article seeks to bring attention to the infuence of cultural framings…

Biogenic silica in tidal freshwater marsh sediments and vegetation (Schelde estuary, Belgium)

NARCIS (Netherlands)

Struyf, E.; van Damme, S.; Gribsholt, B.; Middelburg, J.J.; Meire, P.

2005-01-01

To date, estuarine ecosystem research has mostly neglected silica cycling in freshwater intertidal marshes. However, tidal marshes can store large amounts of biogenic silica (BSi) in vegetation and sediment. BSi content of the typical freshwater marsh plants Phragmites australis, Impatiens

Effects of salinity on freshwater fishes in coastal plain drainages in the southeastern U.S.

Science.gov (United States)

Peterson, Mark S.; Meador, Michael R.

1994-01-01

This review focuses on the influence of salinity on freshwater fishes in coastal rivers and estuaries of the southeastern U.S. Influences of salinity on freshwater fish species can be explained partly through responses evidenced by behavior, physiology, growth, reproduction, and food habits during all aspects of life history. Factors influencing the rate of salinity change affect the community structure and dynamics of freshwater fishes in brackish environments. Our understanding of the relation between salinity and the life history of freshwater fishes is limited because little ecological research has been conducted in low-salinity habitats that we consider an “interface” between freshwater streams and the estuary proper. Much of the available data are descriptive in nature and describe best general patterns, but more specific studies are required to better determine the influence of salinity on freshwater fishes. Improved understanding of the influence of human-induced changes on the productivity and viability of these important systems will require a new research focus.

Salinity tolerances and use of saline environments by freshwater turtles: implications of sea level rise.

Science.gov (United States)

Agha, Mickey; Ennen, Joshua R; Bower, Deborah S; Nowakowski, A Justin; Sweat, Sarah C; Todd, Brian D

2018-03-25

The projected rise in global mean sea levels places many freshwater turtle species at risk of saltwater intrusion into freshwater habitats. Freshwater turtles are disproportionately more threatened than other taxa; thus, understanding the role of salinity in determining their contemporary distribution and evolution should be a research priority. Freshwater turtles are a slowly evolving lineage; however, they can adapt physiologically or behaviourally to various levels of salinity and, therefore, temporarily occur in marine or brackish environments. Here, we provide the first comprehensive global review on freshwater turtle use and tolerance of brackish water ecosystems. We link together current knowledge of geographic occurrence, salinity tolerance, phylogenetic relationships, and physiological and behavioural mechanisms to generate a baseline understanding of the response of freshwater turtles to changing saline environments. We also review the potential origins of salinity tolerance in freshwater turtles. Finally, we integrate 2100 sea level rise (SLR) projections, species distribution maps, literature gathered on brackish water use, and a phylogeny to predict the exposure of freshwater turtles to projected SLR globally. From our synthesis of published literature and available data, we build a framework for spatial and phylogenetic conservation prioritization of coastal freshwater turtles. Based on our literature review, 70 species (∼30% of coastal freshwater turtle species) from 10 of the 11 freshwater turtle families have been reported in brackish water ecosystems. Most anecdotal records, observations, and descriptions do not imply long-term salinity tolerance among freshwater turtles. Rather, experiments show that some species exhibit potential for adaptation and plasticity in physiological, behavioural, and life-history traits that enable them to endure varying periods (e.g. days or months) and levels of saltwater exposure. Species that specialize on

The effect of Congo River freshwater discharge on Eastern Equatorial Atlantic climate variability

Energy Technology Data Exchange (ETDEWEB)

Materia, Stefano [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Gualdi, Silvio; Navarra, Antonio [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Terray, Laurent [Sciences de l' Univers au CERFACS, URA1875 CERFACS/CNRS, Toulouse (France)

2012-11-15

The surface ocean explains a considerable part of the inter-annual Tropical Atlantic variability. The present work makes use of observational datasets to investigate the effect of freshwater flow on sea surface salinity (SSS) and temperature (SST) in the Gulf of Guinea. In particular, the Congo River discharges a huge amount of freshwater into the ocean, affecting SSS in the Eastern Equatorial Atlantic (EEA) and stratifying the surface layers. The hypothesis is that an excess of river runoff emphasize stratification, influencing the ocean temperature. In fact, our findings show that SSTs in the Gulf of Guinea are warmer in summers following an anomalously high Congo spring discharge. Vice versa, when the river discharges low freshwater, a cold anomaly appears in the Gulf. The response of SST is not linear: temperature anomalies are considerable and long-lasting in the event of large freshwater flow, while in dry years they are less remarkable, although still significant. An excess of freshwater seems able to form a barrier layer, which inhibits vertical mixing and the entrainment of the cold thermocline water into the surface. Other processes may contribute to SST variability, among which the net input of atmospheric freshwater falling over EEA. Likewise the case of continental runoff from Congo River, warm anomalies occur after anomalously rainy seasons and low temperatures follow dry seasons, confirming the effect of freshwater on SST. However, the two sources of freshwater anomaly are not in phase, so that it is possible to split between atypical SST following continental freshwater anomalies and rainfall anomalies. Also, variations in air-sea fluxes can produce heating and cooling of the Gulf of Guinea. Nevertheless, atypical SSTs cannot be ascribed to fluxes, since the temperature variation induced by them is not sufficient to explain the SST anomalies appearing in the Gulf after anomalous peak discharges. The interaction processes between river runoff, sea

Radionuclide transfer to freshwater biota species: review of Russian language studies

Energy Technology Data Exchange (ETDEWEB)

Fesenko, S., E-mail: s.fesenko@iaea.or [International Atomic Energy Agency, NAAL, 1400 Vienna (Austria); Fesenko, J.; Sanzharova, N.; Karpenko, E.; Titov, I. [Russian Institute of Agricultural Radiology and Radioecology, 249020 Obninsk (Russian Federation)

2011-01-15

Around 130 publications reporting studies on radionuclide transfer to freshwater biota species conducted in the former USSR were reviewed to provide the concentration ratio values. None of these studies were available up to now in the English language reviews or publications. The values derived have been compared with the CR values used for freshwater systems in the International reviews. For some radionuclides reviewed in this paper, the data are in good agreement with the mean CR values presented earlier, however for some of them, in particular, for {sup 241}Am (bivalve molluscs, gastropods and pelagic fish), {sup 60}Co (gastropods, benthic fish and insect larvae), {sup 90}Sr and {sup 137}Cs (benthic fish and zooplankton), the mean values given here are substantially different from those presented earlier. The data reported in this paper for thirty five radionuclides and eleven groups of freshwater species markedly improve the extent of available data for evaluation of radiation impact on freshwater species. - Research highlights: {yields} The paper provides information on concentration ratios to freshwater biota species for 35 radionuclides. Many of the data are for {sup 90}Sr and {sup 137}Cs. {yields} For the majority of radionuclides reviewed in this paper, the CR values are in good agreement with those given in the recent International reviews. {yields} For {sup 241}Am (bivalve molluscs, gastropods and pelagic fish), {sup 60}Co (gastropods, benthic fish and insect larvae), {sup 90}Sr and {sup 137}Cs (benthic fish and zooplankton), the mean values based on review of the Russian language publications are substantially different from those presented in the International reviews. {yields} Information presented in the paper significantly increases the availability of data on radionuclide accumulation in freshwater species.

Freshwater biodiversity and aquatic insect diversification.

Science.gov (United States)

Dijkstra, Klaas-Douwe B; Monaghan, Michael T; Pauls, Steffen U

2014-01-01

Inland waters cover less than 1% of Earth's surface but harbor more than 6% of all insect species: Nearly 100,000 species from 12 orders spend one or more life stages in freshwater. Little is known about how this remarkable diversity arose, although allopatric speciation and ecological adaptation are thought to be primary mechanisms. Freshwater habitats are highly susceptible to environmental change and exhibit marked ecological gradients. Standing waters appear to harbor more dispersive species than running waters, but there is little understanding of how this fundamental ecological difference has affected diversification. In contrast to the lack of evolutionary studies, the ecology and habitat preferences of aquatic insects have been intensively studied, in part because of their widespread use as bioindicators. The combination of phylogenetics with the extensive ecological data provides a promising avenue for future research, making aquatic insects highly suitable models for the study of ecological diversification.

Freshwater fishes of Tsitsikamma National Park

Directory of Open Access Journals (Sweden)

I.A. Russell

2002-12-01

Full Text Available This study aimed to determine the distribution and relative abundance of freshwater fishes in the Tsitsikamma National Park. Fish assemblages in six river systems were sampled in 2001, with a total of 323 fish from eight species recorded. Indigenous fish collected included four freshwater species (Pseudobarbus afer, Pseudobarbus tenuis, Sandelia capensis, Anguilla mossambica, three estuarine species (Monodactylus falciformis, Caffrogobius gilchristi, Myxus capensis, and one alien (Micropterus salmoides. One additional indigenous species (Galaxias zebratus and two aliens (Salmo trutta, Oncorhynchus mykiss could potentially occur within the park. The topography and locality of the park presents a unique opportunity to meaningfully conserve the endangered P. tenuis as well as other fish characteristic of the eastern reaches of the Cape Floristic Region. Management action is required to minimise opportunities for further establishment and spread of alien fish species and to conserve indigenous fish assemblages within the park.

Dissolved organic carbon in the freshwater tidal reaches of the Schelde estuary

DEFF Research Database (Denmark)

Muylaert, K.; Dasseville, R.; De Brabandere, Loreto

2005-01-01

To unravel the factors that regulate DOC dynamics in the freshwater tidal reaches of the Schelde estuary, DOC concentration and biodegradability were monitored in the upper Schelde estuary and its major tributaries. Although the Schelde estuary possesses a densely populated and industrialized...... catchment, our data suggest that the bulk of DOC in the freshwater tidal reaches is not derived from waste water. This was concluded from the low biodegradability of DOC (on average 9%), DOC concentrations that are close to the mean for European rivers (4.61 mg/l) and the absence of an inverse relationship....../l), these blooms did not appear to produce large quantities of DOC in the freshwater tidal reaches as DOC concentrations were low when phytoplankton biomass was high. The fact that DOC concentrations were high in winter and decreased in summer suggests a predominantly terrestrial source of DOC in the freshwater...

Documentation of Significant Losses in Cornus florida L. Populations throughout the Appalachian Ecoregion

International Nuclear Information System (INIS)

Oswalt, Ch.M.; Oswalt, S.N.

2010-01-01

Over the last three decades the fungus Discula destructiva Redlin has severely impacted Cornus florida L. (flowering dogwood hereafter dogwood) populations throughout its range. This study estimates historical and current dogwood populations (number of trees) across the Appalachian ecoregion. Objectives were to (1) quantify current dogwood populations in the Appalachian eco region, (2) quantify change over time in dogwood populations, and (3) identify trends in dogwood population shifts. Data from the USDA Forest Service Forest Inventory and Analysis (FIA) database were compiled from 41 FIA units in 13 states for county-level estimates of the total number of all live dogwood trees on timberland within the Appalachian eco region. Analysis of covariance, comparing historical and current county-level dogwood population estimates with average change in forest density as the covariate, was used to identify significant changes within FIA units. Losses ranging from 25 to 100 percent of the sample population (ρ<.05) were observed in 33 of the 41 (80 percent) sampled FIA units. These results indicate that an important component of the eastern deciduous forest has experienced serious losses throughout the Appalachians and support localized empirical results and landscape-scale anecdotal evidence.

Assessment of human-natural system characteristics influencing global freshwater supply vulnerability

Science.gov (United States)

Padowski, Julie C.; Gorelick, Steven M.; Thompson, Barton H.; Rozelle, Scott; Fendorf, Scott

2015-10-01

Global freshwater vulnerability is a product of environmental and human dimensions, however, it is rarely assessed as such. Our approach identifies freshwater vulnerability using four broad categories: endowment, demand, infrastructure, and institutions, to capture impacts on natural and managed water systems within the coupled human-hydrologic environment. These categories are represented by 19 different endogenous and exogenous characteristics affecting water supply vulnerability. By evaluating 119 lower per capita income countries (Yemen and Djibouti nearly as vulnerable. Surprising similarities in vulnerability were also found among geographically disparate nations such as Vietnam, Sri Lanka, and Guatemala. Determining shared patterns of freshwater vulnerability provides insights into why water supply vulnerabilities are manifested in human-water systems at the national scale.

Marine and freshwater toxins.

Science.gov (United States)

Hungerford, James M

2006-01-01

In a very busy and exciting year, 2005 included First Action approval of a much needed official method for paralytic shellfish toxins and multiple international toxin symposia highlighted by groundbreaking research. These are the first-year milestones and activities of the Marine and Freshwater Toxins Task Force and Analytical Community. Inaugurated in 2004 and described in detail in last year's General Referee Report (1) this international toxins group has grown to 150 members from many regions and countries. Perhaps most important they are now making important and global contributions to food safety and to providing alternatives to animal-based assays. Official Method 2005.06 was first approved in late 2004 by the Task Force and subsequently Official First Action in 2005 (2) by the Methods Committee on Natural Toxins and Food Allergens and the Official Methods Board. This nonproprietary method (3) is a precolumn oxidation, liquid chromatographic method that makes good use of fluorescence detection to provide high sensitivity detection of the saxitoxins. It has also proven to be rugged enough for regulatory use and the highest level of validation. As pointed out in the report of method principle investigator and Study Director James Lawrence, approval of 2005.06 now provides the first official alternative to the mouse bioassay after many decades of shellfish monitoring. This past year in April 2005 the group also held their first international conference, "Marine and Freshwater Toxins Analysis: Ist Joint Symposium and AOAC Task Force Meeting," in Baiona, Spain. The 4-day conference consisted of research and stakeholder presentations and symposium-integrated subgroup sessions on ciguatoxins, saxitoxin assays and liquid chromatography (LC) methods for saxitoxins and domoic acids, okadaiates and azaspiracids, and yessotoxins. Many of these subgroups were recently formed in 2005 and are working towards their goals of producing officially validated analytical methods

Feeding ecology of the freshwater crab Trichodactylus borellianus (Decapoda: Trichodactylidae in the floodplain of the Paraná River, southern South America

Directory of Open Access Journals (Sweden)

Verónica Williner

2013-09-01

Full Text Available Freshwater crabs are not commonly considered to be an important group in trophic webs, and this might be due to a lack of knowledge about their trophic roles in aquatic ecosystems. Trichodactylus borellianus is one of the most common and widely distributed freshwater crabs in the floodplains of the southern South American rivers. The main objective of the present study was to examine the trophic role of T. borellianus, in the floodplain of the Paraná River, and its relationships with the freshwater littoral community. The trophic spectrum of this species was characterized for both sexes and individuals of different sizes (adults and juveniles, throughout daily and seasonal cycles. Samples were collected from the aquatic vegetation of three shallow lakes. The diet composition and the feeding activity of T. borellianus were evaluated through the examination of the stomach contents and their degree of emptiness. This crab species consumed several plant and animal items, including amoebas, rotifers, oligochaetes, copepods, cladocerans, and insect larvae. Moreover, this species consumes filamentous and unicellular algae, diatoms, fungi, and macrophytic remains. The predatory habits varied with the season and time of day, and variations in the feeding activity of the juveniles and adults were detected and documented. The diversity of food items eaten by this crab suggests that its trophic role in the community as an omnivore and opportunistic predator provides a connection among several trophic levels from both aquatic and terrestrial communities.

[BIODIVERSITY OF ACANTHOCEPHALANS (ACANTHOCEPHALA) IN FRESHWATER FISHES OF ASIATIC SUB-ARCTIC REGION].

Science.gov (United States)

Atrashkevich, G I; Mikhailova, E I; Orlovskaya, O M; Pospekhov, V V

2016-01-01

The analysis of taxonomical and ecological diversity of acanthocephalans in fishes of Asiatic sub-Arctic region freshwaters, summarizing changes in modern views on species composition, life cycles, and ecology of background groups of these parasites is given. A priority role of studies provided by O. N. Bauer and his scientific school in organization and development of these aspects of acanthocephalology is demonstrated. Special attention is paid to the assessment of acanthocephalan biodiversity of the genus Neoechinorhynchus, the background group of freshwater fish parasites of the Asiatic sub-Arctic region, and an original key for their species is given. The distribution of acanthocephalans of the genus Acanthocephalus in northeastern Asia is analyzed and prospective study of this parasite group, evolutionary associated with freshwater isopods of the genus Asellus as intermediate hosts, is outlined. The absence of documented evidences on intermediate hosts of other background parasites of freshwater fishes in the region, acanthocephalans of the genus Metechinorhynchus, is revealed. It is assumed that subsequent taxonomic revisions based both on morphological and molecular genetic studies are necessary for the reliable revealing of species composition in each genus of the background acanthocephalans from freshwater fishes of Northern Asia. Theoretical significance of the study of acanthocephalan life cycles and revealing their natural intermediate hosts for the reliable estimation of structural and functional organization of their host-parasite systems in different parts of the range is substantiated and the possibility of the distribution of taxonomic conclusions in new territories is analyzed. A brief annotated taxonomical list of freshwater acanthocephalans of the Asiatic sub-Arctic region is given.

Overwintering of sea trout (Salmo trutta) in freshwater

DEFF Research Database (Denmark)

Thomsen, Dennis; Koed, Anders; Nielsen, Christian

2007-01-01

Brown trout (Salmo trutta) show large phenotypic plasticity. Juveniles may reside in their native freshwater habitat until maturation or migrate into the ocean as 1- to 3-year-old smolts. Sea-going fish (sea trout) reside at sea for 2-3 years until migrating back to their native stream for reprod......Brown trout (Salmo trutta) show large phenotypic plasticity. Juveniles may reside in their native freshwater habitat until maturation or migrate into the ocean as 1- to 3-year-old smolts. Sea-going fish (sea trout) reside at sea for 2-3 years until migrating back to their native stream...... for reproduction. However, immature fish may leave the ocean during their first or second winter at sea and overwinter in freshwater. The question is why does this occur? We tested the hypothesis that hypo-osmoregulatory capacity is compromised by low temperature in two coastal sea trout populations, one...... representing high salinity and the other, low salinity. Immature sea-run trout were caught in lower parts of two rivers during winter and acclimated to laboratory conditions. Subgroups were challenged with high salinity or low water temperature or both, and their osmoregulatory performance was investigated...

Magnetic resonance imaging of live freshwater mussels (Unionidae)

Science.gov (United States)

Michael, Holliman F.; Davis, Denise; Bogan, Arthur E.; Kwak, Thomas J.; Cope, W. Gregory; Levine, Jay F.

2008-01-01

We examined the soft tissues of live freshwater mussels, Eastern elliptio Elliptio complanata, via magnetic resonance imaging (MRI), acquiring data with a widely available human whole-body MRI system. Anatomical features depicted in the profile images included the foot, stomach, intestine, anterior and posterior adductor muscles, and pericardial cavity. Noteworthy observations on soft tissue morphology included a concentration of lipids at the most posterior aspect of the foot, the presence of hemolymph-filled fissures in the posterior adductor muscle, the presence of a relatively large hemolymph-filled sinus adjacent to the posterior adductor muscle (at the ventral-anterior aspect), and segmentation of the intestine (a diagnostic description not reported previously in Unionidae). Relatively little is known about the basic biology and ecological physiology of freshwater mussels. Traditional approaches for studying anatomy and tissue processes, and for measuring sub-lethal physiological stress, are destructive or invasive. Our study, the first to evaluate freshwater mussel soft tissues by MRI, clarifies the body plan of unionid mussels and demonstrates the efficacy of this technology for in vivoevaluation of the structure, function, and integrity of mussel soft tissues.

An ultrasonic method for separation of epiphytic microbes from freshwater submerged macrophytes.

Science.gov (United States)

Cai, Xianlei; Gao, Guang; Yang, Jing; Tang, Xiangming; Dai, Jiangyu; Chen, Dan; Song, Yuzhi

2014-07-01

Epiphytic microbes are common inhabitants of freshwater submerged macrophytes, which play an important role in aquatic ecosystems. An important precondition for studying the epiphytic microbes is having an effective method of separating the attached microbes from the host macrophytes. We developed an ultrasound-based method for separating epiphytic microbes from freshwater submerged macrophytes, optimized the conditions of ultrasonic separation with an orthogonal experimental design, and compared the optimized ultrasonic method with manual separation. This method can be particularly useful for freshwater submerged macrophytes having a complex morphology. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

2008 NWFSC Tidal Freshwater Genetics Results

Energy Technology Data Exchange (ETDEWEB)

David Teel

2009-05-01

Genetic Analysis of Juvenile Chinook Salmon for inclusion in 'Ecology of Juvenile Salmon in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2008. Annual Report to Bonneville Power Administration, Contract DE-AC05-76RL01830.'

Assess and Adapt: Coordinated Ecoregional Forest Vulnerability Assessments Covering the Upper Midwest and Northeast in Support of Climate-informed Decision-making

Science.gov (United States)

Swanston, C.; Janowiak, M.; Handler, S.; Butler, P.; Brandt, L.; Iverson, L.; Thompson, F.; Ontl, T.; Shannon, D.

2016-12-01

Forest ecosystem vulnerability assessments are rapidly becoming an integral component of forest management planning, in which there is increasing public expectation that even near-term activities explicitly incorporate information about anticipated climate impacts and risks. There is a clear desire among forest managers for targeted assessments that address critical questions about species and ecosystem vulnerabilities while delivering this information in an accessible format. We developed the Ecosystem Vulnerability Assessment Approach (EVAA), which combines multiple quantitative models, expert elicitation from scientists and land managers, and a templated report structure oriented to natural resource managers. The report structure includes relevant information on the contemporary landscape, past climate, future climate projections, impact model results, and a transparent vulnerability assessment of species and ecosystems. We have used EVAA in seven ecoregional assessments covering 246 million acres of forestland across the upper Midwest and Northeast (www.forestadaptation.org; five published, two in review). We convened a panel of local forest ecology and management experts in each assessment area to examine projected climate effects on system drivers, stressors, and dominant species, as well as the current adaptive capacity of the major ecoregional forest ecosystems. The panels provided a qualitative assessment of the vulnerability of forest ecosystems to climate change over the next century. Over 130 authors from dozens of organizations collaborated on these peer-reviewed assessment publications, which are delivered to thousands of stakeholders through live and recorded webinars, online briefs, and in-person trainings and seminars. The assessments are designed to be used with the Adaptation Workbook (www.adaptationworkbook.org), a planning tool that works at multiple scales and has generated more than 200 real-world forest adaptation demonstration projects.

Diversity of deep-sea fishes of the Easter Island Ecoregion

Science.gov (United States)

Easton, Erin E.; Sellanes, Javier; Gaymer, Carlos F.; Morales, Naiti; Gorny, Matthias; Berkenpas, Eric

2017-03-01

The Easter Island Ecoregion is in the center of the South Pacific gyre and experiences ultra-oligotrophic conditions that could make it highly susceptible to global change and anthropogenic activities, so it is imperative that these regions are characterized and studied so that conservation and sustainable management strategies can be developed. From the few studies from the region, we know that the coastal areas are relatively depauperate and have relatively high rates of endemism. Here, we present a brief report from the first video observations from this region of the deep-dwelling fishes from ROV exploration of benthic communities from 157 to 281 m and baited drop-camera videos from 150 to 1850 m. We observed a total of 55 fish species from the ROV and Drop-Cam surveys; nine could not be assigned family level or lower, 26 were observed in the ROV surveys, 29 were observed in the Drop-Cam surveys, nine were observed with both survey methods, at least six species are potentially new to science, and nine species were observed at deeper depths than previously reported. These new reports may be indicative of the unique oceanographic conditions in the area and the relative isolation of the communities that have provided opportunity for the evolution of new species and favorable conditions for range expansion. In contrast, these new reports may be indicative of the severe undersampling in the south Pacific at mesopelagic depths. The prevalence of potentially new species suggests that the region likely harbors a wealth of undiscovered biodiversity.

Fast evolution from precast bricks: genomics of young freshwater populations of threespine stickleback Gasterosteus aculeatus.

Directory of Open Access Journals (Sweden)

Nadezhda V Terekhanova

2014-10-01

Full Text Available Adaptation is driven by natural selection; however, many adaptations are caused by weak selection acting over large timescales, complicating its study. Therefore, it is rarely possible to study selection comprehensively in natural environments. The threespine stickleback (Gasterosteus aculeatus is a well-studied model organism with a short generation time, small genome size, and many genetic and genomic tools available. Within this originally marine species, populations have recurrently adapted to freshwater all over its range. This evolution involved extensive parallelism: pre-existing alleles that adapt sticklebacks to freshwater habitats, but are also present at low frequencies in marine populations, have been recruited repeatedly. While a number of genomic regions responsible for this adaptation have been identified, the details of selection remain poorly understood. Using whole-genome resequencing, we compare pooled genomic samples from marine and freshwater populations of the White Sea basin, and identify 19 short genomic regions that are highly divergent between them, including three known inversions. 17 of these regions overlap protein-coding genes, including a number of genes with predicted functions that are relevant for adaptation to the freshwater environment. We then analyze four additional independently derived young freshwater populations of known ages, two natural and two artificially established, and use the observed shifts of allelic frequencies to estimate the strength of positive selection. Adaptation turns out to be quite rapid, indicating strong selection acting simultaneously at multiple regions of the genome, with selection coefficients of up to 0.27. High divergence between marine and freshwater genotypes, lack of reduction in polymorphism in regions responsible for adaptation, and high frequencies of freshwater alleles observed even in young freshwater populations are all consistent with rapid assembly of G. aculeatus

Fast evolution from precast bricks: genomics of young freshwater populations of threespine stickleback Gasterosteus aculeatus.

Science.gov (United States)

Terekhanova, Nadezhda V; Logacheva, Maria D; Penin, Aleksey A; Neretina, Tatiana V; Barmintseva, Anna E; Bazykin, Georgii A; Kondrashov, Alexey S; Mugue, Nikolai S

2014-10-01

Adaptation is driven by natural selection; however, many adaptations are caused by weak selection acting over large timescales, complicating its study. Therefore, it is rarely possible to study selection comprehensively in natural environments. The threespine stickleback (Gasterosteus aculeatus) is a well-studied model organism with a short generation time, small genome size, and many genetic and genomic tools available. Within this originally marine species, populations have recurrently adapted to freshwater all over its range. This evolution involved extensive parallelism: pre-existing alleles that adapt sticklebacks to freshwater habitats, but are also present at low frequencies in marine populations, have been recruited repeatedly. While a number of genomic regions responsible for this adaptation have been identified, the details of selection remain poorly understood. Using whole-genome resequencing, we compare pooled genomic samples from marine and freshwater populations of the White Sea basin, and identify 19 short genomic regions that are highly divergent between them, including three known inversions. 17 of these regions overlap protein-coding genes, including a number of genes with predicted functions that are relevant for adaptation to the freshwater environment. We then analyze four additional independently derived young freshwater populations of known ages, two natural and two artificially established, and use the observed shifts of allelic frequencies to estimate the strength of positive selection. Adaptation turns out to be quite rapid, indicating strong selection acting simultaneously at multiple regions of the genome, with selection coefficients of up to 0.27. High divergence between marine and freshwater genotypes, lack of reduction in polymorphism in regions responsible for adaptation, and high frequencies of freshwater alleles observed even in young freshwater populations are all consistent with rapid assembly of G. aculeatus freshwater genotypes

Value-chain analysis of freshwater apple snail (Pila globosa used for on-farm feeds in the freshwater prawn farming sector in Bangladesh

Directory of Open Access Journals (Sweden)

S.A.A. Nahid

2013-12-01

Full Text Available Growth of the freshwater prawn (Macrobrachium rosenbergii sector in Bangladesh since 1970s has been supported by natural availability of freshwater apple snail (Pila globosa, used for on-farm prawn feeds. The present study identified the current configuration of the value-chain benefits and constraints of freshwater apple snail in south-western Bangladesh in August 2011, based upon Rapid Market Appraisal (RMA approach. The site of snail collection was Chanda Beel in Gopalganj district, while trading, processing and final consumption was represented by Rayer Mahal Bazar in Khulna district. There were seven different nodes recognized throughout the value chain. Snail marketing was identified as a seasonal business and took place during June to November each year. Between 1995 and 2011 the price of whole snail, meat and shell has increased by 800%, 325% and 315%, respectively. The abundance of snail had been reduced and its demand has increased due to the expansion of the prawn farming industry. Prawn farmers preferred snail meat due to its’ low cost (US$ 0.21 kg-1 as a source of protein compared to commercial prawn feed (US$ 0.41 kg-1. Snail harvesting and processing were considered as additional livelihood options for the poor, where 60% of the labour involved in snail harvesting were women, and 95% the de-shelling workforce. Induced breeding in captivity and sustainable management in nature as well as development of commercial production of apple snails might reduce the pressure on ecosystems and positively contributed to the continued expansion of freshwater prawn farming in Bangladesh.

Effect of sustainability information on consumers' liking of freshwater prawn (Macrobrachium rosenbergii).

Science.gov (United States)

Simoes, Julia Siqueira; Mársico, Eliane Teixeira; da Cruz, Adriano Gomes; de Freitas, Mônica Queiroz; Doro, Laís Higino; Conte-Junior, Carlos Adam

2015-12-01

This research aimed to investigate whether consumer acceptance is affected by information on sustainable practices on the product label. Hedonic evaluations of freshwater prawns were performed by 80 consumers under three aspects: the blind condition - consumers taste samples without information; expected - without tasting samples, consumers evaluated the message 'Freshwater prawns were grown using sustainable practices, reducing environmental impacts caused by traditional breeding'; informed - in which prawns were tasted and the card evaluated. For the entire consumer group, it was observed that the message about sustainability on packaging increased freshwater prawn acceptability (8.25, expected condition (E) versus 6.75, blind condition (B)). High scores were observed under all three test conditions, ranging from 6 (like slightly) to 9 (like extremely), on a 9-point scale. It can be concluded that the use of sustainable information can influence consumers' perception and increase their preference toward freshwater prawns, and even increase the sensory attributes of the product. © 2014 Society of Chemical Industry.

Effects of pollution on freshwater fish

International Nuclear Information System (INIS)

McKim, J.M.; Christensen, G.M.; Tucker, J.H.; Benoit, D.A.; Lewis, M.J.

1974-01-01

Various aspects of pollution effects on fishes are reviewed under the following headings: methodology; water quality; pesticide pollutants; industrial pollutants; domestic pollutants; radioactive pollutants; and other pollutants. A table is presented to show acute and chronic toxicity of inorganic and organic pollutants to freshwater fish. (U.S.)

Ammonia-oxidizing Bacteria and Archaea in the Rhizosphere of Freshwater Macrophytes

DEFF Research Database (Denmark)

Herrmann, Martina; Schramm, Andreas

2007-01-01

AMMONIA-OXIDIZING ARCHAEA AND BACTERIA IN THE RHIZOSPHERE OF FRESHWATER MACROPHYTES Martina Herrmann and Andreas Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Denmark Aquatic macrophytes such as Littorella uniflora and Lobelia dortmanna release oxygen from...... their roots and thereby stimulate nitrification and coupled nitrification-denitrification in their rhizosphere. However, oxygen release and inorganic nitrogen concentrations differ markedly between macrophyte species. We therefore propose (i) that the rhizosphere of freshwater macrophytes harbours a species......-specific microbial community distinct from that of unvegetated sediment and (ii) that aquatic macrophytes have an impact on abundance and activity of nitrifying and denitrifying bacteria in freshwater sediment. The goal of this study was to test these hypotheses for the key functional group for coupled nitrification...

Gulf-Wide Information System, Environmental Sensitivity Index Freshwater Fish Database, Geographic NAD83, LDWF (2001) [esi_freshwater_fish_LDWF_2001

Data.gov (United States)

Louisiana Geographic Information Center — This data set contains sensitive biological resource data for freshwater (inland) fish species in coastal Louisiana. Vector polygons represent water-bodies and other...

Characterization of a Freshwater Crab Sudanonautes aubryi ...

African Journals Online (AJOL)

SARAH

2014-01-31

Jan 31, 2014 ... 2Faculty of Sciences and Techniques, University Marien Ngouabi - PoB 69 Congo Brazzaville ... to collect and realize a biometric characterization of this common freshwater ... information, which will be used by conservation.

The First Detailed 2H and 18O Isoscapes of Freshwater in Scotland

Science.gov (United States)

Meier-Augenstein, W.; Hoogewerff, J.; Kemp, H. F.; Frew, D.

2012-04-01

Scotland's freshwater lochs and reservoirs provide a vital resource for sustaining biodiversity, agriculture, food production as well as for human consumption. Regular monitoring of freshwater quality by the Scottish Environmental Protection Agency (SEPA) fulfils the legislative requirements but new scientific methods involving stable isotope analysis present an opportunity for delivering on current and nascent government policies [1] and gaining a greater understanding of Scottish waters and their importance in the context of climate change, environmental sustainability and the aforementioned functions. In brief, 2H and 18O isoscapes of Scottish freshwater could be used to support fundamental and applied research in: • Climate change - These first ever isoscapes will provide a baseline against which future environmental impact can be assessed due to changes in the characteristic isotope composition of freshwater lochs and reservoirs. • Scottish branding - Location specific stable isotope signatures of Scottish freshwater have the potential to be used as a tool for provenancing and thus protecting premium Scottish produce such as Scottish beef, Scottish berries and Scottish Whisky. During 2011, freshwater samples were collected with the support of SEPA from more than 80 freshwater lochs and reservoirs across Scotland. Here we present the result of the 2H and 18O stable isotope analyses of these water samples together with the first isoscapes generated based on these data. [1] Adaptation Framework - Adapting Our Ways: Managing Scotland's Climate Risk (2009): Scotland's Biodiversity: It's in Your Hands - A strategy for the conservation and enhancement of biodiversity in Scotland (2005); Recipe For Success - Scotland's National Food and Drink Policy (2009); Scottish Planning Policy Environmental Report (2009); Scottish Planning Policy (SPP) 15 Planning for Rural Development (2005); National Planning Policy Guideline (NPPG) 14: Natural Heritage (1999).

Cylindrospermopsin and Saxitoxin Synthetase Genes in Cylindrospermopsis raciborskii Strains from Brazilian Freshwater

Science.gov (United States)

Hoff-Risseti, Caroline; Dörr, Felipe Augusto; Schaker, Patricia Dayane Carvalho; Pinto, Ernani; Werner, Vera Regina; Fiore, Marli Fatima

2013-01-01

The Cylindrospermopsis raciborskii population from Brazilian freshwater is known to produce saxitoxin derivatives (STX), while cylindrospermopsin (CYN), which is commonly detected in isolates from Australia and Asia continents, has thus far not been detected in South American strains. However, during the investigation for the presence of cyrA, cyrB, cyrC and cyrJ CYN synthetase genes in the genomes of four laboratory-cultured C. raciborskii Brazilian strains, the almost complete cyrA gene sequences were obtained for all strains, while cyrB and cyrC gene fragments were observed in two strains. These nucleotide sequences were translated into amino acids, and the predicted protein functions and domains confirmed their identity as CYN synthetase genes. Attempts to PCR amplify cyrJ gene fragments from the four strains were unsuccessful. Phylogenetic analysis grouped the nucleotide sequences together with their homologues found in known CYN synthetase clusters of C. raciborskii strains with high bootstrap support. In addition, fragments of sxtA, sxtB and sxtI genes involved in STX production were also obtained. Extensive LC-MS analyses were unable to detect CYN in the cultured strains, whereas the production of STX and its analogues was confirmed in CENA302, CENA305 and T3. To our knowledge, this is the first study reporting the presence of cyr genes in South American strains of C. raciborskii and the presence of sxt and cyr genes in a single C. raciborskii strain. This discovery suggests a shift in the type of cyanotoxin production over time of South American strains of C. raciborskii and contributes to the reconstruction of the evolutionary history and diversification of cyanobacterial toxins. PMID:24015317

Cylindrospermopsin and saxitoxin synthetase genes in Cylindrospermopsis raciborskii strains from Brazilian freshwater.

Directory of Open Access Journals (Sweden)

Caroline Hoff-Risseti

Full Text Available The Cylindrospermopsis raciborskii population from Brazilian freshwater is known to produce saxitoxin derivatives (STX, while cylindrospermopsin (CYN, which is commonly detected in isolates from Australia and Asia continents, has thus far not been detected in South American strains. However, during the investigation for the presence of cyrA, cyrB, cyrC and cyrJ CYN synthetase genes in the genomes of four laboratory-cultured C. raciborskii Brazilian strains, the almost complete cyrA gene sequences were obtained for all strains, while cyrB and cyrC gene fragments were observed in two strains. These nucleotide sequences were translated into amino acids, and the predicted protein functions and domains confirmed their identity as CYN synthetase genes. Attempts to PCR amplify cyrJ gene fragments from the four strains were unsuccessful. Phylogenetic analysis grouped the nucleotide sequences together with their homologues found in known CYN synthetase clusters of C. raciborskii strains with high bootstrap support. In addition, fragments of sxtA, sxtB and sxtI genes involved in STX production were also obtained. Extensive LC-MS analyses were unable to detect CYN in the cultured strains, whereas the production of STX and its analogues was confirmed in CENA302, CENA305 and T3. To our knowledge, this is the first study reporting the presence of cyr genes in South American strains of C. raciborskii and the presence of sxt and cyr genes in a single C. raciborskii strain. This discovery suggests a shift in the type of cyanotoxin production over time of South American strains of C. raciborskii and contributes to the reconstruction of the evolutionary history and diversification of cyanobacterial toxins.

The functional response of a freshwater benthic community to cadmium pollution

International Nuclear Information System (INIS)

Faupel, Michael; Ristau, Kai; Traunspurger, Walter

2012-01-01

Theory predicts that in freshwater communities under chemical stress secondary production will decrease while the rate of biomass turnover (P/B) will increase. However, this concept has never been tested on organisms of smaller size (bacteria, protozoans, small metazoans), although they form the basis of the heterotrophic food web. The present work describes the results of a 7-month microcosm study, in which the effects of low and high toxic stress on an entire sediment community were examined, with cadmium (Cd) as the model pollutant (50 and 400 mg Cd kg −1 dry sediment). While metazoans and protozoans generally followed the expected trend, in bacteria both production and P/B decreased under Cd stress. These observations provide new insights into the functioning of freshwater ecosystems and demonstrate the functional consequences of toxicants on biological systems. - Highlights: ► Secondary production of freshwater organisms was estimated under cadmium stress. ► Cadmium generally decreased the production of all taxa. ► The corresponding P/B ratio increased for some taxa. ► Secondary production provides insight into the functioning of polluted ecosystems. - Cadmium alters the biomass turnover rate of a freshwater community.

Adaptive management in the context of barriers in European freshwater ecosystems.

Science.gov (United States)

Birnie-Gauvin, Kim; Tummers, Jeroen S; Lucas, Martyn C; Aarestrup, Kim

2017-12-15

Many natural habitats have been modified to accommodate for the presence of humans and their needs. Infrastructures - such as hydroelectric dams, weirs, culverts and bridges - are now a common occurrence in streams and rivers across the world. As a result, freshwater ecosystems have been altered extensively, affecting both biological and geomorphological components of the habitats. Many fish species rely on these freshwater ecosystems to complete their lifecycles, and the presence of barriers has been shown to reduce their ability to migrate and sustain healthy populations. In the long run, barriers may have severe repercussions on population densities and dynamics of aquatic animal species. There is currently an urgent need to address these issues with adequate conservation approaches. Adaptive management provides a relevant approach to managing barriers in freshwater ecosystems as it addresses the uncertainties of dealing with natural systems, and accommodates for future unexpected events, though this approach may not be suitable in all instances. A literature search on this subject yielded virtually no output. Hence, we propose a step-by-step guide for implementing adaptive management, which could be used to manage freshwater barriers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phylogeography of an island endemic: the Puerto Rican freshwater crab, Epilobocera sinuatifrons

Science.gov (United States)

Benjamin D. Cook; Catherine M. Pringle; Jane M. Hughes

2008-01-01

The endemic Puerto Rican crab, Epilobocera sinuatifrons (Pseudothelphusidae), has a freshwater-dependant life-history strategy, although the species has some capabilities for terrestrial movement as adults. In contrast to all other freshwater decapods on the island (e.g., caridean shrimp), E. sinuatifrons does not undertake amphidromous migration, and is restricted to...

Dose-Time Effect of Crude Oil and Hydro-test Effluent on Freshwater ...

African Journals Online (AJOL)

This work was undertaken to investigate the dose-time effect of crude oil and hydro-test effluent on freshwater and brackish water habitats. The species used for the acute toxicity were freshwater fish, Tilapia guineenis (fry) and a brackish water shrimp, Palaemonetes africanus. Test results indicated that the brackish water ...

CAGE BREEDING OF WARM WATER FRESHWATER FISH SPECIES

Directory of Open Access Journals (Sweden)

Roman Safner

2008-10-01

Full Text Available In the 1970s, Croatia became actively involved in the contemporary trend of breeding fish in floating cages. In addition to various species of marine fishes, breeding was attempted with trout, carp, catfish, cisco and salmon. Of the above freshwater fish species, specific standards were established only for the cage breeding of rainbow trout. Cage breeding of the remaining species remained at the level of occasional attempts, with more of an experimental than a commercial character. The regular attempts to master this technique for cage breeding of warm water freshwater fish species were aimed at achieving the known benefits of such breeding, such as simplicity of implementing technological measures, easier establishment of the breeding system, simpler manipulation, the possibility of denser colonies per unit volume with a high level of production, easier adaptations to market conditions and fewer initial structural investments. Despite the many advantages, the main reasons for the lack of greater implementation of the cage breeding technology for warm water species of freshwater fish include problems in obtaining the appropriate category and quantity of healthy fry, the specificity and applicability of physical and chemical properties of the recipients and human error. In evaluating the advantages and disadvantages, the final decision on the justification of cage breeding for individual warm water freshwater species must be based on both biological and economic factors. Based on the knowledge of cage breeding acquired to date, the rule for virtually all intensive breeding systems is that it is only recommended for those species with high market demand and a high market price. The technology that demands nutrition with highly concentrated feed and other production expenditures is costly, and is therefore not profitable with less expensive fish species. Furthermore, production must be market oriented, i.e. the appropriate market research measures

Effects of Pollution on Freshwater Invertebrates.

Science.gov (United States)

Buikema, A. L., Jr.; Herricks, E. E.

1978-01-01

Presents a literature review of the effects of pollution on freshwater invertebrates, covering publications of 1976-77. Some of the areas covered are: (1) toxicant effects on invertebrates; (2) microcosm and community effects, and (3) biological control of aquatic life. A list of 123 references is also presented. (HM)

Persistent organochlorine pesticide residues in freshwater systems ...

African Journals Online (AJOL)

DRINIE

determined in water and sediment samples of freshwater systems in the Eastern Cape Province of South Africa that ... The organochlorine pesticides (OCPs) in water and sediments ...... Test Methods For Evaluating Solid Waste (3rd edn.) ...

Practical aids for freshwater spill response

International Nuclear Information System (INIS)

Steen, A.E.; Walker, A.H.

1993-01-01

The current research program at API is focused on the environmental and human health effects from oil spills in freshwater habitats. Components of the program include lessons learned from spill response, development of decision-making protocols for the use of chemicals during initial response operations, preparation of a manual for spill response and contingency planning, and a review of the literature on environmental and human health effects from inland spills. API has reviewed past inland spill responses to identify lessons learned. A survey questionnaire has been developed to collect information from freshwater spill responders on their successes and difficulties in response operations. The questionnaire is tailored to focus on the impact to the operations from the absence of technical/scientific data on environmental effects or operation effectiveness/efficiency as well as to identify situations in which the use of particular response or cleanup options is likely to be effective. The questionnaires will be available at the Conference. Published case studies also will be examined for lessons-learned information. The results will be used to identify and prioritize API research needs in freshwater spill response. General concerns about the effectiveness of the toxicity associated with chemicals in spill response has prevented their use in fresh water. API has begun a detailed survey and interview process with state and federal regulatory personnel to identify their concerns and decision criteria to evaluate the use of chemicals in initial spill response. Ten classes of chemicals were identified for consideration: dispersants, shoreline cleaners, shoreline protection agents, herding agents, solidifiers, demulsifiers, emulsion inhibitors, foaming agents, oxidizing agents, and burning agents

Exotic freshwater planarians currently known from Japan

NARCIS (Netherlands)

Sluys, R.; Kawakatsu, M.; Yamamoto, K.

2010-01-01

Biogeographical and taxonomic information on the four non-indigenous freshwater planarians of Japan is reviewed, viz. Dugesia austroasiatica Kawakatsu, 1985, Girardia tigrina (Girard, 1850), G. dorotocephala (Woodworth, 1897), and Rhodax evelinae? Marcus, 1947. The occurrence of Girardia

Dinoflagellates associated with freshwater sponges from the ancient lake baikal.

Science.gov (United States)

Annenkova, Natalia V; Lavrov, Dennis V; Belikov, Sergey I

2011-04-01

Dinoflagellates are a diverse group of protists that are common in both marine and freshwater environments. While the biology of marine dinoflagellates has been the focus of several recent studies, their freshwater relatives remain little-investigated. In the present study we explore the diversity of dinoflagellates in Lake Baikal by identifying and analyzing dinoflagellate sequences for 18S rDNA and ITS-2 from total DNA extracted from three species of endemic Baikalian sponges (Baikalospongia intermedia,Baikalospongia rectaand Lubomirskia incrustans). Phylogenetic analyses of these sequences revealed extensive dinoflagellate diversity in Lake Baikal. We found two groups of sequences clustering within the order Suessiales, known for its symbiotic relationships with various invertebrates. Thus they may be regarded as potential symbionts of Baikalian sponges. In addition,Gyrodinium helveticum, representatives from the genus Gymnodinium, dinoflagellates close to the family Pfiesteriaceae, and a few dinoflagellates without definite affiliation were detected. No pronounced difference in the distribution of dinoflagellates among the studied sponges was found, except for the absence of the Piscinoodinium-like dinoflagellates inL. incrustans. To the best of our knowledge, this is the first study of the diversity of dinoflagellates in freshwater sponges, the first systematic investigation of dinoflagellate molecular diversity in Lake Baikal and the first finding of members of the order Suessiales as symbionts of freshwater invertebrates. Copyright © 2010 Elsevier GmbH. All rights reserved.

Tracking animals in freshwater with electronic tags: past, present and future

Science.gov (United States)

Cooke, Steven J.; Midwood, Jonathan D.; Thiem, Jason D.; Klimley, Peter; Lucas, Martyn C.; Thorstad, Eva B.; Eiler, John; Holbrook, Chris; Ebner, Brendan C.

2013-01-01

Considerable technical developments over the past half century have enabled widespread application of electronic tags to the study of animals in the wild, including in freshwater environments. We review the constraints associated with freshwater telemetry and biologging and the technical developments relevant to their use. Technical constraints for tracking animals are often influenced by the characteristics of the animals being studied and the environment they inhabit. Collectively, they influence which and how technologies can be used and their relative effectiveness. Although radio telemetry has historically been the most commonly used technology in freshwater, passive integrated transponder (PIT) technology, acoustic telemetry and biologgers are becoming more popular. Most telemetry studies have focused on fish, although an increasing number have focused on other taxa, such as turtles, crustaceans and molluscs. Key technical developments for freshwater systems include: miniaturization of tags for tracking small-size life stages and species, fixed stations and coded tags for tracking large samples of animals over long distances and large temporal scales, inexpensive PIT systems that enable mass tagging to yield population- and community-level relevant sample sizes, incorporation of sensors into electronic tags, validation of tag attachment procedures with a focus on maintaining animal welfare, incorporation of different techniques (for example, genetics, stable isotopes) and peripheral technologies (for example, geographic information systems, hydroacoustics), development of novel analytical techniques, and extensive international collaboration. Innovations are still needed in tag miniaturization, data analysis and visualization, and in tracking animals over larger spatial scales (for example, pelagic areas of lakes) and in challenging environments (for example, large dynamic floodplain systems, under ice). There seems to be a particular need for adapting

Vegetable oil sources in diets for freshwater angelfish (Pterophyllum scalare, Cichlidae: growth and thermal tolerance

Directory of Open Access Journals (Sweden)

A.K. Ikeda

2011-06-01

Full Text Available The influence of fatty acid composition of the diets on the productive performance and on cold and heat tolerance of juvenile freshwater angelfish (Pterophyllum scalare, in three different phases, was studied. Phase I studied the productive performance of freshwater angelfish in a completely randomized experimental design with four treatments, canola, linseed, olive and soybean oils and four replicates during 50 days using 192 fish in 16 aquaria. Phase II studied the cold tolerance of juvenile freshwater angelfish using 72 juvenile freshwater angelfish, coming from phase I and maintained in 12 aquaria climatized chamber. The temperature was reduced 1ºC per day, until the observation of 100% fish mortality. Phase III, it was studied the heat tolerance of juvenile freshwater angelfish employing an identical procedure to phase II, but with a daily increase of 1ºC. Significant differences (P>0.05 were not observed for any parameters evaluated. Thus, it was concluded that the type of vegetable oil (canola, linseed, olive and soybean used as a diet supplement did not affect the productive performance, nor the tolerance to cold and heat, of juvenile freshwater angelfish.

Methane emission from tidal freshwater marshes

NARCIS (Netherlands)

Van der Nat, F.J.; Middelburg, J.J.

2000-01-01

In two tidal freshwater marshes, methane emission, production and accumulation in the pore-water have been studied. The two sites differ in their dominant vegetation, i.e., reed and bulrush, and in their heights above sea level. The reed site was elevated in relation to the bulrush site and had

Herbivory on freshwater and marine macrophytes

NARCIS (Netherlands)

Bakker, Elisabeth S.; Wood, Kevin A.; Pagès, Jordi F.; Veen, G.F.; Christianen, Marjolijn J.A.; Santamaría, Luis; Nolet, Bart A.; Hilt, Sabine

2016-01-01

Until the 1990s, herbivory on aquatic vascular plants was considered to be of minor importance, and the predominant view was that freshwater and marine macrophytes did not take part in the food web: their primary fate was the detritivorous pathway. In the last 25 years, a substantial body of

Adaptive management in the context of barriers in European freshwater ecosystems

DEFF Research Database (Denmark)

Birnie-Gauvin, Kim; Tummers, Jeroen S.; Lucas, Martyn C.

2017-01-01

Many natural habitats have been modified to accommodate for the presence of humans and their needs. Infrastructures e such as hydroelectric dams, weirs, culverts and bridges e are now a common occurrence in streams and rivers across the world. As a result, freshwater ecosystems have been altered...... extensively, affecting both biological and geomorphological components of the habitats. Many fish species rely on these freshwater ecosystems to complete their lifecycles, and the presence of barriers has been shown to reduce their ability to migrate and sustain healthy populations. In the long run, barriers...... may have severe repercussions on population densities and dynamics of aquatic animal species. There is currently an urgent need to address these issues with adequate conservation approaches. Adaptive management provides a relevant approach to managing barriers in freshwater ecosystems as it addresses...

Cadmium as toxicant in Freshwater Cyprinid, Labeo rohita

African Journals Online (AJOL)

Sajo

2012-04-24

Apr 24, 2012 ... urbanization, expansion of industrial activity, industrial wasteful effluents .... blood capillaries, and sinusoids were randomly distri- buted. ..... cholinesterase activity of freshwater fish, Oreochromis mossambicus. Peters. Asia.

Bryozoans are returning home: recolonization of freshwater ecosystems inferred from phylogenetic relationships.

Science.gov (United States)

Koletić, Nikola; Novosel, Maja; Rajević, Nives; Franjević, Damjan

2015-01-01

Bryozoans are aquatic invertebrates that inhabit all types of aquatic ecosystems. They are small animals that form large colonies by asexual budding. Colonies can reach the size of several tens of centimeters, while individual units within a colony are the size of a few millimeters. Each individual within a colony works as a separate zooid and is genetically identical to each other individual within the same colony. Most freshwater species of bryozoans belong to the Phylactolaemata class, while several species that tolerate brackish water belong to the Gymnolaemata class. Tissue samples for this study were collected in the rivers of Adriatic and Danube basin and in the wetland areas in the continental part of Croatia (Europe). Freshwater and brackish taxons of bryozoans were genetically analyzed for the purpose of creating phylogenetic relationships between freshwater and brackish taxons of the Phylactolaemata and Gymnolaemata classes and determining the role of brackish species in colonizing freshwater and marine ecosystems. Phylogenetic relationships inferred on the genes for 18S rRNA, 28S rRNA, COI, and ITS2 region confirmed Phylactolaemata bryozoans as radix bryozoan group. Phylogenetic analysis proved Phylactolaemata bryozoan's close relations with taxons from Phoronida phylum as well as the separation of the Lophopodidae family from other families within the Plumatellida genus. Comparative analysis of existing knowledge about the phylogeny of bryozoans and the expansion of known evolutionary hypotheses is proposed with the model of settlement of marine and freshwater ecosystems by the bryozoans group during their evolutionary past. In this case study, brackish bryozoan taxons represent a link for this ecological phylogenetic hypothesis. Comparison of brackish bryozoan species Lophopus crystallinus and Conopeum seurati confirmed a dual colonization of freshwater ecosystems throughout evolution of this group of animals.

Influenza A Virus Surveillance in the Invasive American Mink (Neovison vison) from Freshwater Ecosystems, Northern Spain.

Science.gov (United States)

Gholipour, H; Busquets, N; Fernández-Aguilar, X; Sánchez, A; Ribas, M P; De Pedro, G; Lizarraga, P; Alarcia-Alejos, O; Temiño, C; Cabezón, O

2017-08-01

Influenza A viruses (IAVs) are negative-sense, single-stranded and segmented RNA viruses of the Orthomyxoviridae family that may cause acute respiratory disease in a wide range of birds and mammals. Susceptibility of several species within the family Mustelidae to IAVs has been reported as a result of natural or experimental infections. The objectives of this study were to assess whether free-ranging American mink populations from Northern Spain were infected with IAV and try to define the role of this species in the epidemiology of IAV. Sera from 689 American mink from Northern Spain captured between 2011 and 2014 were tested for the presence of antibodies against IAVs using a commercial competition cELISA. Positive sera were further analysed with haemagglutination inhibition (HI) assay. Fifteen of the 689 (2.2%, 1.3-3.6 CI 95% ) of the American minks analysed were ELISA positive. No significant differences were observed between years of capture, provinces, river basins, sexes or ages of the animals. All seropositive sera resulted negative to the panel strains used in the HI assay, showing that the most relevant strains circulating in swine, the most relevant avian subtypes (H5 and H7) and the H10N4 subtype isolated in minks have not been circulating in this free-ranging exotic carnivore from Spain. In the light of these results, the free-range American mink from Northern Spain do not seem to have an important role in the epidemiology of IAVs. © 2016 Blackwell Verlag GmbH.

Simulations of freshwater lens recharge and salt/freshwater interfaces using the HYDRUS and SWI2 packages for MODFLOW

Directory of Open Access Journals (Sweden)

Szymkiewicz Adam

2018-06-01

Full Text Available The paper presents an evaluation of the combined use of the HYDRUS and SWI2 packages for MODFLOW as a potential tool for modeling recharge in coastal aquifers subject to saltwater intrusion. The HYDRUS package for MODFLOW solves numerically the one-dimensional form of the Richards equation describing water flow in variablysaturated media. The code computes groundwater recharge to or capillary rise from the groundwater table while considering weather, vegetation, and soil hydraulic property data. The SWI2 package represents in a simplified way variable-density flow associated with saltwater intrusion in coastal aquifers. Combining these two packages within the MODFLOW framework provides a more accurate description of vadose zone processes in subsurface systems with shallow aquifers, which strongly depend upon infiltration. The two packages were applied to a two-dimensional problem of recharge of a freshwater lens in a sandy peninsula, which is a typical geomorphologic form along the Baltic and the North Sea coasts, among other places. Results highlighted the sensitivity of calculated recharge rates to the temporal resolution of weather data. Using daily values of precipitation and potential evapotranspiration produced average recharge rates more than 20% larger than those obtained with weekly or monthly averaged weather data, leading to different trends in the evolution of freshwater-saltwater interfaces. Root water uptake significantly influenced both the recharge rate and the position of the freshwater-saltwater interface. The results were less sensitive to changes in soil hydraulic parameters, which in our study were found to affect average yearly recharge rates by up to 13%.

Experimental study of a sustainable hybrid system for thermoelectric generation and freshwater production

Science.gov (United States)

de Souza, Gabriel Fernandes; Tan, Lippong; Singh, Baljit; Ding, Lai Chet; Date, Abhijit

2017-04-01

The paper presents a sustainable hybrid system, which is capable of generating electricity and producing freshwater from seawater using low grade heat source. This proposed system uses low grade heat that can be supplied from solar radiation, industrial waste heat or any other waste heat sources where the temperature is less than 150°C. The concept behind this system uses the Seebeck effect for thermoelectricity generation via incorporating the low boiling point of seawater under sub-atmospheric ambient pressure. A lab-test prototype of the proposed system was built and experimentally tested in RMIT University. The prototype utilised four commercial available thermoelectric generators (Bi2Te3) and a vacuum vessel to achieve the simultaneous production of electricity and freshwater. The temperature profiles, thermoelectric powers and freshwater productions were determined at several levels of salinity to study the influence of different salt concentrations. The theoretical description of system design and experimental results were analysed and discussed in detailed. The experiment results showed that 0.75W of thermoelectricity and 404g of freshwater were produced using inputs of 150W of simulated waste heat and 500g of 3% saline water. The proposed hybrid concept has demonstrated the potential to become the future sustainable system for electricity and freshwater productions.

Future Freshwater Stress on Small Islands: Population, Aridity and Global Warming Targets

Science.gov (United States)

Karnauskas, K. B.; Schleussner, C. F.; Donnelly, J. P.; Anchukaitis, K. J.

2017-12-01

Small island developing states (SIDS) face multiple threats from anthropogenic climate change, including potential changes in freshwater resource availability. Future freshwater stress, including geographic and seasonal variability, has important implications for climate change adaptation scenarios for vulnerable human populations living on islands across the world ocean. Due to a mismatch in spatial scale between SIDS landforms and the horizontal resolution of global climate models (GCMs), SIDS are mostly unaccounted for in GCMs that are used to make future projections of global climate change and its regional impacts. Specific approaches are required to address this gap between broad-scale model projections and regional, policy-relevant outcomes. Here we apply a recently developed methodology to project future changes in aridity in combination with population projections associated with different shared socioeconomic pathways (SSPs) to evaluate overall changes in freshwater stress in SIDS at warming levels of 1.5°C and 2°C above pre-industrial levels. By accounting for evaporative demand a posteriori, we reveal a robust yet spatially variable tendency towards increasing aridity for 16 million people living on islands by mid-century. Although about half of the islands are projected to experience increased rainfall—predominantly in the deep tropics—projected changes in evaporation are more uniform, shifting the global distribution of changes in island freshwater balance towards greater aridity. In many cases, the magnitude of projected drying is comparable to the amplitude of the estimated observed interannual variability, with important consequences for extreme events. While we find that future population growth will dominate changes in projected freshwater stress especially towards the end of the century, projected changes in aridity are found to compound freshwater stress for the vast majority of SIDS. Particularly across the Caribbean region, a

Heliozoa from Nigeria | Wujek | Tropical Freshwater Biology

African Journals Online (AJOL)

A total of seven scaled protistans were observed from four freshwater sites in Nigeria. They include the holiozoan genera Acanthocystis, Polyplacocystis, Pterocystis, and Raphidiophrys. All are new records for Africa. KEY WORDS: Heliozoa, Protozoa, Acanthocystis, Polyplacocystis, Pterocystis, Raphidiophrys Tropical ...

Use of wild trout for PBDE assessment in freshwater environments: Review and summary of critical factors

Directory of Open Access Journals (Sweden)

Juan M. Ríos

2015-11-01

Full Text Available Certain wild animals represent sentinels to address issues related to environmental pollution, since they can provide integrative data on both pollutant exposure and biological effects. Despite their technological benefits, PBDEs are considered a threat to environmental health due to their persistence, toxicity, and capacity to be accumulated. These pollutants have been found geographically widespread in fish, particularly in predator species such as trout. The aim of this work is to critically review the applicability and usefulness of wild trout for assessing PBDEs in freshwater environments. Reviewed reports include data from highly industrialized areas as well as areas from remote regions with relatively low human activity, including European and North American great lakes and freshwater environments in Europe, Greenland, subarctic areas and Patagonia, respectively. A summary of relevant factors were grouped into organism-specific factors (food habits, age, size, lipid content, sex and reproduction, tissue type, mechanism of contaminant uptake and metabolism, and PBDE levels in the surrounding environment (sediment. Five wild trout species [rainbow trout (Oncorhynchus mykiss, brown trout (Salmo trutta, lake trout (Salvelinus namaycush, arctic char (Salvelinus alpinus, and brook trout (Salvelinus fontinalis], collected worldwide within the 1994 to present time frame, were considered. Multivariate techniques (principal component analysis-PCA and mapping approach, showed clear differences in geographic distribution patterns of PBDE levels in trout depending on the region studied: wild trout from European and North American great lakes have the highest PBDE loads. This pattern could be due to high industrial activity at these locations. A correlational approach used to explore intraspecific relationships between PBDE levels and morphometry, showed positive relationships only for brown trout. Further, brown trout showed the highest trout

Filling gaps in a large reserve network to address freshwater conservation needs.

Science.gov (United States)

Hermoso, Virgilio; Filipe, Ana Filipa; Segurado, Pedro; Beja, Pedro

2015-09-15

Freshwater ecosystems and biodiversity are among the most threatened at global scale, but efforts for their conservation have been mostly peripheral to terrestrial conservation. For example, Natura 2000, the world's largest network of protected areas, fails to cover adequately the distribution of rare and endangered aquatic species, and lacks of appropriate spatial design to make conservation for freshwater biodiversity effective. Here, we develop a framework to identify a complementary set of priority areas and enhance the conservation opportunities of Natura 2000 for freshwater biodiversity, using the Iberian Peninsula as a case study. We use a systematic planning approach to identify a minimum set of additional areas that would help i) adequately represent all freshwater fish, amphibians and aquatic reptiles at three different target levels, ii) account for key ecological processes derived from riverscape connectivity, and iii) minimize the impact of threats, both within protected areas and propagated from upstream unprotected areas. Addressing all these goals would need an increase in area between 7 and 46%, depending on the conservation target used and strength of connectivity required. These new priority areas correspond to subcatchments inhabited by endangered and range restricted species, as well as additional subcatchments required to improve connectivity among existing protected areas and to increase protection against upstream threats. Our study should help guide future revisions of the design of Natura 2000, while providing a framework to address deficiencies in reserve networks for adequately protecting freshwater biodiversity elsewhere. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantifying the effect of catchment land-use and water nutrient concentrations on freshwater river and stream biodiversity

NARCIS (Netherlands)

Weijters, M.J.; Janse, J.H.; Alkemade, J.R.M.; Verhoeven, J.T.A.

2009-01-01

A major threat to freshwater taxon diversity is the alteration of natural catchment Land use into agriculture, industry or urban areas and the associated eutrophication of the water. In order to stop freshwater biodiversity loss, it is essential to quantify the relationships between freshwater

Marine nutrient contributions to tidal creeks in Virginia: spawning marine fish as nutrient vectors to freshwater ecosystems

Science.gov (United States)

Macavoy, S. E.; Garman, G. C.

2006-12-01

Coastal freshwater streams are typically viewed as conduits for the transport of sediment and nutrients to the coasts. Some coastal streams however experience seasonal migrations of anadromous fish returning to the freshwater to spawn. The fish may be vectors for the delivery of marine nutrients to nutrient poor freshwater in the form of excreted waste and post-spawning carcasses. Nutrients derived from marine sources are 13C, 15N and 34S enriched relative to nutrients in freshwater. Here we examine sediment, particulate organic matter (POM), invertebrates and fish in two tidal freshwater tributaries of the James River USA. The d15N of POM became elevated (from 3.8 to 6.5%), coincident with the arrival of anadromous river herring (Alosa sp), indicating a pulse of marine nitrogen. However, the elevated 15N was not observed in sediment samples or among invertebrates, which did not experience a seasonal isotopic shift (there were significant differences however among the guilds of invertebrate). Anadromous Alosa aestivalis captured within the tidal freshwater were 13C and 34S enriched (-19.3 and 17.2%, respectively) relative to resident freshwater fishes (-26.4 and 3.6% respectively) captured within 2 weeks of the Alosa. Although it is likely that marine derived nitrogen was detected in the tidal freshwater, it was not in sufficient abundance to change the isotope signature of most ecosystem components.

Current status of parasitic ciliates Chilodonella spp. (Phyllopharyngea: Chilodonellidae) in freshwater fish aquaculture.

Science.gov (United States)

Bastos Gomes, G; Jerry, D R; Miller, T L; Hutson, K S

2017-05-01

Freshwater fish farming contributes to more than two-thirds of global aquaculture production. Parasitic ciliates are one of the largest causes of production loss in freshwater farmed fishes, with species from the genus Chilodonella being particularly problematic. While Chilodonella spp. include 'free-living' fauna, some species are involved in mortality events of fish, particularly in high-density aquaculture. Indeed, chilodonellosis causes major productivity losses in over 16 species of farmed freshwater fishes in more than 14 countries. Traditionally, Chilodonella species are identified based on morphological features; however, the genus comprises yet uncharacterized cryptic species, which indicates the necessity for molecular diagnostic methods. This review synthesizes current knowledge on the biology, ecology and geographic distribution of harmful Chilodonella spp. and examines pathological signs, diagnostic methods and treatments. Recent advances in molecular diagnostics and the ability to culture Chilodonella spp. in vitro will enable the development of preventative management practices and sustained freshwater fish aquaculture production. © 2016 John Wiley & Sons Ltd.

The Implications of Ranaviruses to European farmed and wild freshwater fish

DEFF Research Database (Denmark)

Jensen, Ann Britt Bang

The present thesis explores the implications of ranaviruses to European farmed and wild freshwater fish. The work presented was carried out as a part of the EU project “Risk assessment of new and emerging systemic iridoviral diseases for European fish and aquatic ecosystems” which was initiated...... in 2005 as a reaction to the speculation that ranaviruses might pose a serious threat to both farmed and wild-living freshwater fish and amphibians within the European community. In the present thesis, the purpose is to determine the implications of ranaviruses to European freshwater farmed and wild...... describing the risk of introduction and spread of exotic ranaviruses in European wild and farmed aquatic ecosystems Objectives 1 and 2 have been addressed by experimental trials involving bath challenges of both European farmed and wild fish species and ornamental fish species. The results showed that some...

Cultured branchial epithelia from freshwater fish gills

Science.gov (United States)

Wood; PÄRt

1997-01-01

We have developed a method for the primary culture of gill epithelial cells from freshwater rainbow trout on permeable supports, polyethylene terephthalate membranes ('filter inserts'). Primary cultures of gill cells (6-9 days in Leibowitz L-15 culture medium plus foetal bovine serum and glutamine) are trypsinized and the cells seeded onto the inserts. After 6 days of growth with L-15 medium on both surfaces (approximately isotonic to trout plasma), the cells form a tight epithelium as judged from a progressive rise in transepithelial resistance which reaches a stable plateau for a further 6 days, as long as L-15 exposure is continued on both surfaces. The cultured epithelium (approximately 8 µm thick) typically consists of 2-4 overlapping cell layers organized as in the lamellae in vivo, with large intercellular spaces, multiple desmosomes and putative tight junctions. The cells appear to be exclusively pavement-type cells with an apical surface glycocalyx, an abundance of rough endoplasmic reticulum, no selective DASPEI staining and relatively few mitochondria. Transepithelial resistance (approximately 3.5 k cm2), permeability to a paracellular marker (polyethylene glycol-4000; 0.17x10(-6) cm s-1) and unidirectional flux of Na+ and Cl- (approximately 300 nmol cm-2 h-1) all appear realistic because they compare well with in vivo values; net fluxes of Na+ and Cl- are zero. The preparation acidifies the apical medium, which accumulates a greater concentration of ammonia. Upon exposure to apical freshwater, resistance increases six- to elevenfold and a basolateral-negative transepithelial potential (TEP) develops as in vivo. These responses occur even when mannitol is used to prevent changes in apical osmotic pressure. Net Na+ and Cl- loss rates are low over the first 12 h (-125 nmol cm-2 h-1) but increase substantially by 48 h. The elevated resistance and negative TEP gradually attenuate but remain significantly higher than pre-exposure values after 48 h of apical

Study on Waste Heat Utilization Device of High-Temperature Freshwater in the Modern Marine Diesel Engine

Science.gov (United States)

Wang, Shuaijun; Liu, Chentao; Zhou, Yao

2018-01-01

Based on using the waste heat recycling from high temperature freshwater in marine diesel engine to heat fuel oil tank, lubrication oil tank and settling tank and so on to achieve energy saving, improve fuel efficiency as the goal, study on waste heat utilization device of high-temperature freshwater in the modern marine diesel engine to make the combustion chamber effectively cooled by high-temperature freshwater and the inner liner freshwater temperature heat is effectively utilized and so on to improve the overall efficiency of the power plant of the ship and the diesel optimum working condition.

Injuries by marine and freshwater stingrays: history, clinical aspects of the envenomations and current status of a neglected problem in Brazil.

Science.gov (United States)

Junior, Vidal Haddad; Cardoso, João Luiz Costa; Neto, Domingos Garrone

2013-07-29

Stingrays are a group of rays - cartilaginous fish related to sharks - that have whiplike tails with barbed, usually venomous spines and are found around the world, especially the marine species. Despite recent reports of accidents involving these fish, they are not aggressive, reacting only when stepped on or improperly handled. Injuries by stingrays are seldom mentioned by historians, although they have always been present in riverine communities of inland waters and in South American coasts. Indeed, envenomations by stingrays are quite common in freshwater and marine fishing communities. Although having high morbidity, such injuries are neglected because they have low lethality and usually occur in remote areas, which favor the use of folk remedies. In the present review article, historical aspects of injuries caused by stingrays in Brazil and their distribution on the coast of São Paulo state and riverine communities of the North, Midwest and Southeast regions were studied. In addition, other aspects were analyzed such as clinical features, therapeutic methods, preventive measures and trends in occurrence of these accidents in the country, particularly in areas in which freshwater stingrays had not been previously registered, being introduced after breaching of natural barriers.

Establishing a database of radionuclide transfer parameters for freshwater wildlife

International Nuclear Information System (INIS)

Yankovich, T.; Beresford, N.A.; Fesenko, S.; Fesenko, J.; Phaneuf, M.; Dagher, E.; Outola, I.; Andersson, P.; Thiessen, K.; Ryan, J.; Wood, M.D.; Bollhöfer, A.

2013-01-01

Environmental assessments to evaluate potentials risks to humans and wildlife often involve modelling to predict contaminant exposure through key pathways. Such models require input of parameter values, including concentration ratios, to estimate contaminant concentrations in biota based on measurements or estimates of concentrations in environmental media, such as water. Due to the diversity of species and the range in physicochemical conditions in natural ecosystems, concentration ratios can vary by orders of magnitude, even within similar species. Therefore, to improve model input parameter values for application in aquatic systems, freshwater concentration ratios were collated or calculated from national grey literature, Russian language publications, and refereed papers. Collated data were then input into an international database that is being established by the International Atomic Energy Agency. The freshwater database enables entry of information for all radionuclides listed in ICRP (1983), in addition to the corresponding stable elements, and comprises a total of more than 16,500 concentration ratio (CR wo-water ) values. Although data were available for all broad wildlife groups (with the exception of birds), data were sparse for many organism types. For example, zooplankton, crustaceans, insects and insect larvae, amphibians, and mammals, for which there were CR wo-water values for less than eight elements. Coverage was most comprehensive for fish, vascular plants, and molluscs. To our knowledge, the freshwater database that has now been established represents the most comprehensive set of CR wo-water values for freshwater species currently available for use in radiological environmental assessments

Monitoring endangered freshwater biodiversity using environmental DNA

DEFF Research Database (Denmark)

Thomsen, Philip Francis; Kielgast, Jos; Iversen, Lars Lønsmann

2012-01-01

Freshwater ecosystems are among the most endangered habitats on Earth, with thousands of animal species known to be threatened or already extinct. Reliable monitoring of threatened organisms is crucial for data-driven conservation actions but remains a challenge owing to nonstandardized methods t...

Homogenization patterns of the world’s freshwater fish faunas

Science.gov (United States)

Villéger, Sébastien; Blanchet, Simon; Beauchard, Olivier; Oberdorff, Thierry; Brosse, Sébastien

2011-01-01

The world is currently undergoing an unprecedented decline in biodiversity, which is mainly attributable to human activities. For instance, nonnative species introduction, combined with the extirpation of native species, affects biodiversity patterns, notably by increasing the similarity among species assemblages. This biodiversity change, called taxonomic homogenization, has rarely been assessed at the world scale. Here, we fill this gap by assessing the current homogenization status of one of the most diverse vertebrate groups (i.e., freshwater fishes) at global and regional scales. We demonstrate that current homogenization of the freshwater fish faunas is still low at the world scale (0.5%) but reaches substantial levels (up to 10%) in some highly invaded river basins from the Nearctic and Palearctic realms. In these realms experiencing high changes, nonnative species introductions rather than native species extirpations drive taxonomic homogenization. Our results suggest that the “Homogocene era” is not yet the case for freshwater fish fauna at the worldwide scale. However, the distressingly high level of homogenization noted for some biogeographical realms stresses the need for further understanding of the ecological consequences of homogenization processes. PMID:22025692

Explosive diversification following a benthic to pelagic shift in freshwater fishes

OpenAIRE

Hollingsworth, Phillip R; Simons, Andrew M; Fordyce, James A; Hulsey, C Darrin

2013-01-01

Background Interspecific divergence along a benthic to pelagic habitat axis is ubiquitous in freshwater fishes inhabiting lentic environments. In this study, we examined the influence of this habitat axis on the macroevolution of a diverse, lotic radiation using mtDNA and nDNA phylogenies for eastern North America’s most species-rich freshwater fish clade, the open posterior myodome (OPM) cyprinids. We used ancestral state reconstruction to identify the earliest benthic to pelagic transition ...

Luminescence properties of a nanoporous freshwater diatom.

Science.gov (United States)

Goswami, Bondita; Choudhury, Amarjyoti; Buragohain, Alak K

2012-01-01

Freshwater diatom frustules show special optical properties. In this paper we observed luminescence properties of the freshwater diatom Cyclotella meneghiniana. To confirm the morphological properties we present scanning electron microscopy (SEM) images. X-ray diffraction (XRD) studies were carried out to visualize the structural properties of the frustules, confirming that silica present in diatom frustules crystallizes in an α-quartz structure. Study of the optical properties of the silica frustules of diatoms using ultra-violet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy confirmed that the diatom C. meneghiniana shows luminescence in the blue region of the electromagnetic spectrum when irradiated with UV light. This property of diatoms can be exploited to obtain many applications in day-to-day life. Also, using time-resolved photoluminescence spectroscopy (TRPL) it was confirmed that this species of diatom shows bi-exponential decay. Copyright © 2011 John Wiley & Sons, Ltd.

Acute toxicity of polyacrylamide flocculants to early life stages of freshwater mussels

Science.gov (United States)

Buczek, Sean B.; Cope, W. Gregory; McLaughlin, Richard A.; Kwak, Thomas J.

2017-01-01

Polyacrylamide has become an effective tool for reducing construction-related suspended sediment and turbidity, which are considered to have significant adverse impacts on aquatic ecosystems and are a leading cause of the degradation of North American streams and rivers. However, little is known about the effects of polyacrylamide on many freshwater organisms, and prior to the present study, no information existed on the toxicity of polyacrylamide compounds to native freshwater mussels (family Unionidae), one of the most imperiled faunal groups globally. Following standard test guidelines, we exposed juvenile mussels (test duration 96 h) and glochidia larvae (test duration 24 h) to 5 different anionic polyacrylamide compounds and 1 non-ionic compound. Species tested included the yellow lampmussel (Lampsilis cariosa), an Atlantic Slope species that is listed as endangered in North Carolina; the Appalachian elktoe (Alasmidonta raveneliana), a federally endangered Interior Basin species; and the washboard (Megalonaias nervosa), a common Interior Basin species. We found that median lethal concentrations (LC50s) of polyacrylamide ranged from 411.7 to >1000 mg/L for glochidia and from 126.8 to >1000 mg/L for juveniles. All LC50s were orders of magnitude greater (2–3) than concentrations typically recommended for turbidity control (1–5 mg/L), regardless of their molecular weight or charge density. The results demonstrate that the polyacrylamide compounds tested were not acutely toxic to the mussel species and life stages tested, indicating minimal risk of short-term exposure from polyacrylamide applications in the environment. However, other potential uses of polyacrylamide in the environment (e.g., wastewater treatment, paper processing, mining, algae removal) and their chronic or sublethal effects remain uncertain and warrant additional investigation.

Natural and anthropogenic factors affecting freshwater lenses in coastal dunes of the Adriatic coast

Science.gov (United States)

Cozzolino, Davide; Greggio, Nicolas; Antonellini, Marco; Giambastiani, Beatrice Maria Sole

2017-08-01

This study characterizes the near-shore portion of the shallow coastal aquifer included in the Ravenna area (Northern Italy) with special attention to the roles of coastal dunes as freshwater reservoirs and their buffer on groundwater salinity. The paper focuses on the presence and evolution of freshwater lenses below coastal dunes and highlights the existing differences between preserved natural dunes and dunes strongly affected by human intervention. The influence that multiple natural and anthropogenic factors, such as land cover, local drainage network, and beach erosion have on the presence, size and evolution of the freshwater lenses in the aquifer is quantified and discussed. The methodology includes multiple seasonal monitoring and sampling campaigns of physical (water level, salinity, and temperature) and chemical (major cations and anions) groundwater parameters. Results indicate that freshwater lenses, where existing, are limited in thickness (about 1-2 m). Proximity to drainage ditches as well as limited dune elevation and size do not allow the formation and permanent storage of large freshwater lenses in the aquifer below the dunes. The pine forest land cover, that replaced the typical bush or sand cover, intensifies evapotranspiration reducing net infiltration and freshwater storage. The cation species distribution in the water shows that a freshening process is ongoing in preserved natural sites with stable or advancing beaches, whereas a salinization process is ongoing in anthropogenic-impacted areas with strongly-fragmented dune systems. Currently, the thin freshwater lenses in the shallow Ravenna coastal aquifer are limited in space and have no relevance for irrigation or any other human activity. The dune-beach system, however, is the recharge zone of the coastal aquifer and its protection is important to reduce water and soil salinization, which in turn control the health of the whole coastal ecosystem.

The freshwater balance of polar regions in transient simulations from 1500 to 2100 AD using a comprehensive coupled climate model

Energy Technology Data Exchange (ETDEWEB)

Lehner, Flavio; Raible, Christoph C.; Hofer, Dominik; Stocker, Thomas F. [University of Bern, Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, Bern (Switzerland)

2012-07-15

The ocean and sea ice in both polar regions are important reservoirs of freshwater within the climate system. While the response of these reservoirs to future climate change has been studied intensively, the sensitivity of the polar freshwater balance to natural forcing variations during preindustrial times has received less attention. Using an ensemble of transient simulations from 1500 to 2100 AD we put present-day and future states of the polar freshwater balance in the context of low frequency variability of the past five centuries. This is done by focusing on different multi-decadal periods of characteristic external forcing. In the Arctic, freshwater is shifted from the ocean to sea ice during the Maunder Minimum while the total amount of freshwater within the Arctic domain remains unchanged. In contrast, the subsequent Dalton Minimum does not leave an imprint on the slow-reacting reservoirs of the ocean and sea ice, but triggers a drop in the import of freshwater through the atmosphere. During the twentieth and twenty-first century the build-up of freshwater in the Arctic Ocean leads to a strengthening of the liquid export. The Arctic freshwater balance is shifted towards being a large source of freshwater to the North Atlantic ocean. The Antarctic freshwater cycle, on the other hand, appears to be insensitive to preindustrial variations in external forcing. In line with the rising temperature during the industrial era the freshwater budget becomes increasingly unbalanced and strengthens the high latitude's Southern Ocean as a source of liquid freshwater to lower latitude oceans. (orig.)

Species persistence: a re-look at the freshwater fish fauna of Chennai, India

Directory of Open Access Journals (Sweden)

J.D.M. Knight

2010-11-01

Full Text Available Loss of habitat is one of the prime reasons for species extinction. It is generally established that certain classes of animals are more prone to extinction than others due to their restricted use of available habitats. Freshwater fish are among these sensitive animals. While local extinctions have rendered some species rare throughout their geographical range, many others have demonstrated higher levels of persistence. This paper focuses on a recent in-depth study of the primary freshwater fishes in and around Chennai. The study that spanned a period of two years recorded a total of 75 species of primary freshwater fish, of which 17 are new reports.

Macrophytes: Freshwater Forests of Lakes and Rivers.

Science.gov (United States)

McDermid, Karla J.; Naiman, Robert J.

1983-01-01

Physical, chemical, and biological effects on macrophytes (aquatic plants) on the freshwater ecosystem are discussed. Research questions and issues related to these organisms are also discussed, including adaptations for survival in a wet environment, ecological consequences of large-scale macrophyte eradication, seasonal changes in plant…

Benthic freshwater nematode community dynamics under conditions ...

African Journals Online (AJOL)

Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, ...

Assessing exposure risks for freshwater tilapia species posed by mercury and methylmercury.

Science.gov (United States)

Cheng, Yi-Hsien; Lin, Yi-Jun; You, Shu-Han; Yang, Ying-Fei; How, Chun Ming; Tseng, Yi-Ting; Chen, Wei-Yu; Liao, Chung-Min

2016-08-01

Waterborne and dietborne exposures of freshwater fish to mercury (Hg) in the forms of inorganic (Hg(II)) and organic (methylmercury or MeHg) affect their growth, development, and reproduction. However, an integrated mechanistic risk model framework to predict the impact of Hg(II)/MeHg on freshwater fish is lacking. Here, we integrated biokinetic, physiological and biogeographic data to calibrate and then establish key risk indices-hazardous quotient and exceedance risk-for freshwater tilapia species across geographic ranges of several major rivers in Taiwan. We found that Hg(II) burden was highest in kidney followed by gill, intestine, liver, blood, and muscle. Our results showed that Hg was less likely to pose mortality risk (mortality rate less than 5 %) for freshwater tilapia species. However, Hg is likely to pose the potential hazard to aquatic environments constrained by safety levels for aquatic organisms. Sensitivity analysis showed that amount of Hg accumulated in tilapia was most influenced by sediment uptake rate. Our approach opens up new possibilities for predicting future fish population health with the impacts of continued Hg exposure to provide information on which fish are deemed safe for human consumption.

Observations on the use of tarantula burrows by the anurans Leptodactylus bufonius (Leptodactylidae and Rhinella major (Bufonidae in the Dry Chaco ecoregion of Bolivia

Directory of Open Access Journals (Sweden)

Christopher M. Schalk

2014-06-01

Full Text Available Some species of anurans have been observed utilizing burrows of other animals, such as rodents and tarantulas. Here we report the observations of two anuran species, Leptodactylus bufonius and Rhinella major, utilizing the burrows of tarantulas (Acanthoscurria sp.; Family Theraphosidae in the dry Chaco ecoregion of Bolivia. Both species of anurans never co-occurred with tarantulas in the burrows and used burrows that were wider in diameter and closer to breeding ponds as compared to the total available tarantula burrows in the area. These burrows may serve as refuges from predators, especially for conspicuous, calling males.

DISTRIBUTION OF HEAVY METALS AMONG THE COMPONENTS OF FRESHWATER ECOSYSTEMS (REVIEW)

OpenAIRE

N. Kolesnyk

2014-01-01

Purpose. To review scientific sources on the distribution of heavy metals among the components of freshwater ecosystems. Findings. The review of the works of many scientists showed that heavy metals are widespread in the biotic and abiotic components of freshwater ecosystems. The article highlights the distribution of heavy metals in water, bottom sediments, natural food base, fish organs and tissues. It has been shown that as a result of global pollution of the ecosystem, the majority of...

Impacts of Freshwater Impoundment in the West Loch of Pearl Harbor

Science.gov (United States)

1993-05-01

absence of applicable non-point standards, the "Yellow Book" criteria for freshwater aquatic life or domestic water supply could be applied to evaluate the...Waimalu, Waipahu, Wahiawa, and Ewa water use districts and contains the largest groundwater body on Oahu, supplying more than 50 percent of the island’s...irrigation; desalt existing brackish water supplies, and; 3 create a freshwater impoundment in West Loch. 6I I I The Board of Water Supply (BWS) and

Human activities cause distinct dissolved organic matter composition across freshwater ecosystems

Science.gov (United States)

Williams, Clayton J.; Frost, Paul C.; Morales-Williams, Ana M.; Larson, James H.; Richardson, William B.; Chiandet, Aisha S.; Xenopoulos, Marguerite A.

2016-01-01

Dissolved organic matter (DOM) composition in freshwater ecosystems is influenced by interactions between physical, chemical, and biological processes that are controlled, at one level, by watershed landscape, hydrology, and their connections. Against this environmental template, humans may strongly influence DOM composition. Yet, we lack a comprehensive understanding of DOM composition variation across freshwater ecosystems differentially affected by human activity. Using optical properties, we described DOM variation across five ecosystem groups of the Laurentian Great Lakes Region: large lakes, Kawartha Lakes, Experimental Lakes Area, urban stormwater ponds, and rivers (n = 184 sites). We determined how between ecosystem variation in DOM composition related to watershed size, land use and cover, water quality measures (conductivity, dissolved organic carbon (DOC), nutrient concentration, chlorophyll a), and human population density. The five freshwater ecosystem groups had distinctive DOM composition from each other. These significant differences were not explained completely through differences in watershed size nor spatial autocorrelation. Instead, multivariate partial least squares regression showed that DOM composition was related to differences in human impact across freshwater ecosystems. In particular, urban/developed watersheds with higher human population densities had a unique DOM composition with a clear anthropogenic influence that was distinct from DOM composition in natural land cover and/or agricultural watersheds. This nonagricultural, human developed impact on aquatic DOM was most evident through increased levels of a microbial, humic-like parallel factor analysis component (C6). Lotic and lentic ecosystems with low human population densities had DOM compositions more typical of clear water to humic-rich freshwater ecosystems but C6 was only present at trace to background levels. Consequently, humans are strongly altering the quality of DOM in

Prevalence of Clonorchis sinensis infection in freshwater fishes in northeastern China.

Science.gov (United States)

Zhang, Y; Chang, Q C; Zhang, Y; Na, L; Wang, W T; Xu, W W; Gao, D Z; Liu, Z X; Wang, C R; Zhu, X Q

2014-08-29

The prevalence of Clonorchis sinensis infection in freshwater fishes was surveyed in Heilongjiang Province, northeastern China, between August 2011 and September 2013. Thirteen species of freshwater fish (n=3221) and one species of shrimp (n=93) were collected from Songhua river, Nenjiang river and other lakes or ponds in 37 sites of 15 representative cities in Heilongjiang Province. They were individually examined by digestion technique, and the C. sinensis metacercariae were identified morphologically followed by confirmation using sequences of the second internal transcribed spacer of ribosomal DNA. Ten of the 13 examined species of freshwater fishes were infected with C. sinensis metacercariae, while all shrimps were negative. The overall prevalence of C. sinensis infection in 3221 examined freshwater fishes was 19.96%, with 42.57% (272/639) in Pseudorasbora parva, 22.55% (83/368) in Hemicculter leuciclus, 20.44% (121/592) in Carassius auratus, 17.71% (68/384) in Saurogobio dabryi, 10.85% (23/212) in Rhodeus ocellatus, 10.54% (48/455) in Phoxinus lagowskii, 8.20% (21/256) in Perccottus glehnii, 6.25% (5/80) in Misgurnus anguillicaudatus, 4.55% (1/22) in Xenocypris davidi, and 1.49% (1/67) in Cyprinus carpio. The average infection intensity in P. parva was 103.3 encysted metacercariae per gram of fish meat in Zhaoyuan city. The average prevalence of C. sinensis infection in Songhua river, Nenjiang river and lakes or ponds were 31.96% (503/1574), 11.30% (102/903) and 7.93% (59/744), respectively. The prevalence of C. sinensis infection in Zhaoyuan city (43.68%) was the highest among all sampling locations. These results revealed a high-prevalence of C. sinensis infection in freshwater fishes in Heilongjiang Province, northeastern China, posing significant public health concern. Copyright © 2014 Elsevier B.V. All rights reserved.

Freshwater Choices in China: Options That Will Impact South and Southeast Asia

Science.gov (United States)

2014-12-04

economies in the world. To sustain this economic growth and transform chronic hunger into food self-sufficiency, both China and India have embarked...FRESHWATER CHOICES IN CHINA: OPTIONS THAT WILL IMPACT SOUTH AND SOUTHEAST ASIA A Monograph by Mr. Steven M. Nystrom...TITLE AND SUBTITLE Freshwater Choices in China: Options that will Impact South and Southeast Asia 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

Global priorities for conservation of threatened species, carbon storage, and freshwater services

DEFF Research Database (Denmark)

Larsen, Frank Wugt; Londoño-Murcia, Maria C.; Turner, Will R.

2011-01-01

The potential of global biodiversity conservation efforts to also deliver critical benefits, such as carbon storage and freshwater services, is still unclear. Using spatially explicit data on 3,500 range-restricted threatened species, carbon storage, and freshwater provision to people, we conducted...... for which spatial planning and appropriate conservation mechanisms (e.g., payments for ecosystem services) can be used to realize synergies and mitigate tradeoffs....

Determinants of family planning use among married women in bale eco-region, Southeast Ethiopia: a community based study.

Science.gov (United States)

Gonie, Alemayehu; Wudneh, Alemayehu; Nigatu, Dejene; Dendir, Zelalem

2018-03-12

Family planning is the ability of individuals and couples to anticipate and attain their desired number of children and the spacing and timing of their births. Providing family planning could prevent maternal deaths by allowing women to delay motherhood, space births, avoid unintended pregnancies and abortions, and stop childbearing when they reach their desired family size. Despite the fact that family planning is advantageous for maternal and newborn health and the services and commodities are free of charge, the reason of not using modern family planning methods is unclear in Bale Eco-Region. Therefore, this study assessed the contraceptive prevalence rate and its determinants among women in Bale Eco-Region, Ethiopia. A community-based cross-sectional study design (both quantitative and qualitative methods) was conducted from December 2016 to February 2017. Five hundred sixty-seven women were successfully interviewed using structured and pre-tested questionnaire. A multistage sampling technique was employed. Data were entered into Epi-data version 3.1 and exported to SPSS version 21. Logistic regression analyses were done and a significant association was declared at p-value less than 0.05. All focus group discussions and key informant interviews were recorded and analyzed thematically. The overall contraceptive prevalence rate was 41.5%. Injectable (48.1%), implants (22.6%) and pills (20.0%) were the most contraceptive methods utilized by study participants. Spousal (husband's) opposition (38.8%), religious beliefs (17.7%), concern and fear of side effects (14.8%), and distance of family planning service (5.9%) were the reasons for not using contraceptive methods. Having more than seven deliveries (AOR = 2.98, CI = 1.91-6.10, P = 0.000) and having birth interval less than 24 months between the last two children (AOR = 3.8, CI = 13.41-21.61, P = 0.003) were significantly associated with utilization of contraceptive methods. Low

Measuring benefits of protected area management: trends across realms and research gaps for freshwater systems.

Science.gov (United States)

Adams, Vanessa M; Setterfield, Samantha A; Douglas, Michael M; Kennard, Mark J; Ferdinands, Keith

2015-11-05

Protected areas remain a cornerstone for global conservation. However, their effectiveness at halting biodiversity decline is not fully understood. Studies of protected area benefits have largely focused on measuring their impact on halting deforestation and have neglected to measure the impacts of protected areas on other threats. Evaluations that measure the impact of protected area management require more complex evaluation designs and datasets. This is the case across realms (terrestrial, freshwater, marine), but measuring the impact of protected area management in freshwater systems may be even more difficult owing to the high level of connectivity and potential for threat propagation within systems (e.g. downstream flow of pollution). We review the potential barriers to conducting impact evaluation for protected area management in freshwater systems. We contrast the barriers identified for freshwater systems to terrestrial systems and discuss potential measurable outcomes and confounders associated with protected area management across the two realms. We identify key research gaps in conducting impact evaluation in freshwater systems that relate to three of their major characteristics: variability, connectivity and time lags in outcomes. Lastly, we use Kakadu National Park world heritage area, the largest national park in Australia, as a case study to illustrate the challenges of measuring impacts of protected area management programmes for environmental outcomes in freshwater systems. © 2015 The Author(s).

River and wetland classifications for freshwater conservation ...

African Journals Online (AJOL)

River and wetland classifications for freshwater conservation planning in KwaZulu-Natal, South Africa. ... regional- or provincial-scale conservation planning. The hierarchical structure of the classifications provides scope for finer resolution, by the addition of further levels, for application at a sub-regional or municipal scale.

Microplastic effect thresholds for freshwater benthic macroinvertebrates

NARCIS (Netherlands)

Redondo Hasselerharm, P.E.; Dede Falahudin, Dede; Peeters, E.T.H.M.; Koelmans, A.A.

2018-01-01

Now that microplastics have been detected in lakes, rivers and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates

In Silico characterization of growth hormone from freshwater ...

African Journals Online (AJOL)

dimensional (3D) structure prediction and evolutionary profile of growth hormone (GH) from 14 ornamental freshwater fishes. The analyses were performed using the sequence data of growth hormone gene (gh) and its encoded GH protein.

Mapping potential freshwater services, and their representation within Protected Areas (PAs, under conditions of sparse data. Pilot implementation for Cambodia

Directory of Open Access Journals (Sweden)

Leonardo Sáenz

2016-07-01

Full Text Available Freshwater is arguably one of Earth’s most threatened natural resources, on which more than 7 billion people depend. Pressures on freshwater resources from infrastructure, resource development, agricultural pollution and deforestation are mounting, particularly in developing countries. To date, conservation responses such as Protected Areas (PAs have not typically targeted freshwater ecosystems and their services, and thus little is known about the effectiveness of these efforts in protecting them. This paper proposes and pilots an innovative freshwater services metrics framework to quantify the representation of potential freshwater services in PAs under conditions of scarce data, with a pilot application for Cambodia. Our results indicate that conservation actions have more effectively represented potential freshwater regulation services than potential freshwater provisioning services, with major rivers remaining generally unprotected. Results from the framework are then used to propose a series of context and region specific management options to improve the conservation of freshwater services in Cambodia. There is an acute need for such management options, as the country’s food security depends largely on important freshwater ecosystems such as the Tonle Sap Lake and the deep water pools systems of the Mekong River. The framework proposed can be applied in other countries or large river basins to explore the degree of representation of freshwater services within PAs systems, under conditions of sparse data.

Improved protocols to accelerate the assembly of DNA barcode reference libraries for freshwater zooplankton.

Science.gov (United States)

Elías-Gutiérrez, Manuel; Valdez-Moreno, Martha; Topan, Janet; Young, Monica R; Cohuo-Colli, José Angel

2018-03-01

Currently, freshwater zooplankton sampling and identification methodologies have remained virtually unchanged since they were first established in the beginning of the XX century. One major contributing factor to this slow progress is the limited success of modern genetic methodologies, such as DNA barcoding, in several of the main groups. This study demonstrates improved protocols which enable the rapid assessment of most animal taxa inhabiting any freshwater system by combining the use of light traps, careful fixation at low temperatures using ethanol, and zooplankton-specific primers. We DNA-barcoded 2,136 specimens from a diverse array of taxonomic assemblages (rotifers, mollusks, mites, crustaceans, insects, and fishes) from several Canadian and Mexican lakes with an average sequence success rate of 85.3%. In total, 325 Barcode Index Numbers (BINs) were detected with only three BINs (two cladocerans and one copepod) shared between Canada and Mexico, suggesting a much narrower distribution range of freshwater zooplankton than previously thought. This study is the first to broadly explore the metazoan biodiversity of freshwater systems with DNA barcodes to construct a reference library that represents the first step for future programs which aim to monitor ecosystem health, track invasive species, or improve knowledge of the ecology and distribution of freshwater zooplankton.

Land use patterns, ecoregion, and microcystin relationships in U.S. lakes and reservoirs: a preliminary evaluation

Science.gov (United States)

Beaver, John R.; Manis, Erin E.; Loftin, Keith A.; Graham, Jennifer L.; Pollard, Amina I.; Mitchell, Richard M.

2014-01-01

A statistically significant association was found between the concentration of total microcystin, a common class of cyanotoxins, in surface waters of lakes and reservoirs in the continental U.S. with watershed land use using data from 1156 water bodies sampled between May and October 2007 as part of the USEPA National Lakes Assessment. Nearly two thirds (65.8%) of the samples with microcystin concentrations ≥1.0 μg/L (n = 126) were limited to three nutrient and water quality-based ecoregions (Corn Belt and Northern Great Plains, Mostly Glaciated Dairy Region, South Central Cultivated Great Plains) in watersheds with strong agricultural influence. canonical correlation analysis (CCA) indicated that both microcystin concentrations and cyanobacteria abundance were positively correlated with total nitrogen, dissolved organic carbon, and temperature; correlations with total phosphorus and water clarity were not as strong. This study supports a number of regional lake studies that suggest that land use practices are related to cyanobacteria abundance, and extends the potential impacts of agricultural land use in watersheds to include the production of cyanotoxins in lakes.

Freshwater conservation planning in South Africa: Milestones to ...

African Journals Online (AJOL)

2012-03-01

Mar 1, 2012 ... freshwaters, implemented through a water resource classifica- tion system ... piled for each of South Africa's 19 Water Management Areas, which are ..... et al., 2011) and integrated water and land-use prioritisation. (Nel et al.

Predicting the 137Cs Contamination of Freshwater Fish in Hong Kong

International Nuclear Information System (INIS)

Poon, C.B.; Au, S.M.

1999-01-01

A predictive method for estimating the 137 Cs contamination of freshwater fish in Hong Kong after an acute deposition is presented. This method applies a published aquatic model to the freshwater fish culture ponds in Hong Kong. The predicted transfer coefficient, in terms of peak concentration in fish (wet weight) per unit deposition, is found to be generally lower than those observed in some European and UK lakes after the Chernobyl accident. While the water-fish concentration factor is undoubtedly an important factor, some unique features of the local freshwater fish culture systems, such as the absence of further radioactivity input from catchment to the fish ponds after deposition, and high removal of radioactivity by sedimentation, also play significant roles. Sensitivity of model parameters and uncertainties of prediction are also studied. This predictive model can serve as a useful tool in emergency planning and in countermeasure implementation during a nuclear emergency in Hong Kong. (author)

Incipient toxicity of lithium to freshwater organisms representing a salmonid habitat

International Nuclear Information System (INIS)

Emery, R.; Klopfer, D.C.; Skalski, J.R.

1981-07-01

Because the eventual development of fusion power reactors could increase the mining, use and disposal of lithium five-fold by the year 2000, potential effects from unusual amounts of lithium in aquatic environments were investigated. Freshwater oganisms representing a Pacific Northwest salmonid habitat were exposed to elevated conentrations of lithium. Nine parameters were used to determine the incipient toxicity of lithium to rainbow trout (Salmo gairdneri), insect larvae (Chironomus sp.), and Columbia River periphyton. All three groups of biota were incipiently sensitive to lithium at concentrations ranging between 0.1 and 1 mg/L. These results correspond with the incipient toxicity of beryllium, a chemically similar component of fusion reactor cores. A maximum lithium concentration of 0.01 mg/L occurs naturally in most freshwater environments (beryllium is rarer). Therefore, a concentration range of 0.01 to 0.1 mg/L may be regarded as approaching toxic concentrations when assessing the hazards of lithium in freshwaters

Pharmaceuticals and personal care products (PPCPs in the freshwater aquatic environment

Directory of Open Access Journals (Sweden)

Anekwe Jennifer Ebele

2017-03-01

Full Text Available Pharmaceuticals and personal care products (PPCPs are a unique group of emerging environmental contaminants, due to their inherent ability to induce physiological effects in human at low doses. An increasing number of studies has confirmed the presence of various PPCPs in different environmental compartments, which raises concerns about the potential adverse effects to humans and wildlife. Therefore, this article reviews the current state-of-knowledge on PPCPs in the freshwater aquatic environment. The environmental risk posed by these contaminants is evaluated in light of the persistence, bioaccumulation and toxicity criteria. Available literature on the sources, transport and degradation of PPCPs in the aquatic environment are evaluated, followed by a comprehensive review of the reported concentrations of different PPCP groups in the freshwater aquatic environment (water, sediment and biota of the five continents. Finally, future perspectives for research on PPCPs in the freshwater aquatic environment are discussed in light of the identified research gaps in current knowledge.

Toxicology of freshwater cyanobacteria.

Science.gov (United States)

Liyanage, H M; Arachchi, D N Magana; Abeysekara, T; Guneratne, L

2016-07-02

Many chemical contaminants in drinking water have been shown to cause adverse health effects in humans after prolonged exposure. Cyanobacteria are one of the most potent and diverse groups of photosynthetic prokaryotes. One key component of cyanobacterial success in the environment is the production of potent toxins as secondary metabolites, which have been responsible for numerous adverse health impacts in humans. Anthropogenic activities have led to the increase of eutrophication in freshwater bodies' worldwide, causing cyanobacterial blooms to become more frequent. The present article will discuss about harmful cyanobacteria and their toxicology with special references to microcystin, nodularin, and cylindrospermopsin.

Forest land cover continues to exacerbate freshwater acidification despite decline in sulphate emissions

International Nuclear Information System (INIS)

Dunford, Robert W.; Donoghue, Daniel N.M.; Burt, Tim P.

2012-01-01

Evidence from a multi-date regional-scale analysis of both high-flow and annual-average water quality data from Galloway, south-west Scotland, demonstrates that forest land cover continues to exacerbate freshwater acidification. This is in spite of significant reductions in airborne pollutants. The relationship between freshwater sulphate and forest cover has decreased from 1996 to 2006 indicating a decrease in pollutant scavenging. The relationship between forest cover and freshwater acidity (pH) is, however, still present over the same period, and does not show conclusive signs of having declined. Furthermore, evidence for forest cover contributing to a chlorine bias in marine ion capture suggests that forest scavenging of sea-salts may mean that the forest acidification effect may continue in the absence of anthropogenic pollutant inputs, particularly in coastal areas. - Highlights: ► Forest cover and water chemistry remain linked despite decreased sulphate emissions. ► Forest cover has significant relationships SO 4 2− , Cl − , Na + , pH, ANC and Na:Cl ratio. ► Forest cover: pH relationships shows some evidence of decline 1996–2006. ► Forest cover: freshwater sulphate relationships show evidence of decline 1996–2006. ► Natural forest-mechanisms may exacerbate acidification, particularly sea-salt scavenging. - Relationships between forest land cover and freshwater pH continue to be evident despite declines in anthropogenic pollutant sulphate deposition; sea-salt scavenging may play a role.

Can environmental impact assessments alone conserve freshwater fish biota? Review of the Chilean experience

International Nuclear Information System (INIS)

Lacy, Shaw Nozaki; Meza, Francisco J.; Marquet, Pablo A.

2017-01-01

Chile was one of many countries that initiated environmental impact assessments in the 1990s, and has relied on their use for species conservation and territorial planning without the use of larger-scale environmental and ecological planning. The capacity of Chile's environmental impact assessment system (SEIA) to evaluate resident freshwater fishes and the potential impacts of water projects and aquaculture activities – two categories of projects that create direct threats to freshwater fishes – are assessed. Of the 3997 such submissions to the SEIA, only 0.6% conducted any freshwater fish assessment, and only 0.1% conducted any quantitative assessment of expected impacts from the associated project. The small number of assessments was characterized by poor study design, inconsistent sampling methodology, and species misidentification. Traditional assessments failed to include freshwater fish ecology in the general assessment framework. The new strategic environmental evaluation system only underscores the need for vastly improved field sampling protocols and assessment methodologies.

Can environmental impact assessments alone conserve freshwater fish biota? Review of the Chilean experience

Energy Technology Data Exchange (ETDEWEB)

Lacy, Shaw Nozaki, E-mail: shaw.lacy@gmail.com [Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago (Chile); Departmento de Ecosistemas y Medio Ambiente, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul (Chile); Centro Interdisciplinario de Cambio Global, Vicuña Mackenna 4860, Macul (Chile); Meza, Francisco J. [Departmento de Ecosistemas y Medio Ambiente, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul (Chile); Centro Interdisciplinario de Cambio Global, Vicuña Mackenna 4860, Macul (Chile); Marquet, Pablo A. [Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago (Chile); Instituto de Ecología y Biodiversidad, Las Palmeras 345, Santiago (Chile); Centro Interdisciplinario de Cambio Global, Vicuña Mackenna 4860, Macul (Chile)

2017-03-15

Chile was one of many countries that initiated environmental impact assessments in the 1990s, and has relied on their use for species conservation and territorial planning without the use of larger-scale environmental and ecological planning. The capacity of Chile's environmental impact assessment system (SEIA) to evaluate resident freshwater fishes and the potential impacts of water projects and aquaculture activities – two categories of projects that create direct threats to freshwater fishes – are assessed. Of the 3997 such submissions to the SEIA, only 0.6% conducted any freshwater fish assessment, and only 0.1% conducted any quantitative assessment of expected impacts from the associated project. The small number of assessments was characterized by poor study design, inconsistent sampling methodology, and species misidentification. Traditional assessments failed to include freshwater fish ecology in the general assessment framework. The new strategic environmental evaluation system only underscores the need for vastly improved field sampling protocols and assessment methodologies.

Indirect Consequences of Recreational Fishing in Freshwater Ecosystems: An Exploration from an Australian Perspective

Directory of Open Access Journals (Sweden)

Shelley Burgin

2017-02-01

Full Text Available Recreational fishing in freshwater ecosystems is a popular pastime in Australia. Although most native fish are endemic, the fauna is depauperate compared to any landmass of similar size. With commercial fishing no longer a major industry in the country’s freshwaters, the future sustainability of these ecosystems will depend heavily on the actions of recreational fishers. However, there has been limited focus on the consequences of recreational fishing in freshwaters. There is particularly a dearth of information on the indirect consequences of fishers on the waterbodies they depend on for their sport. After outlining the respective trends in commercial and recreational fishing in Australia as a basis for placing the sport in context, the indirect impacts of fishers on water quality, movement (walking, off-road vehicles, the introduction/translocation of fauna (particularly fish, the dispersal of flora and the transmission of fish disease and pathogens are reviewed. It is concluded that with the decline of commercial fishing, the competition between commercial fin-fishing and recreational fishing is negligible, at least throughout most of the country. It is also concluded that each of the issues addressed has the potential to be detrimental to the long-term sustainability of the freshwater ecosystems that the fishers depend on for their recreation. However, information on these issues is scant. This is despite the current and predicted popularity of freshwater recreational fishing continuing to increase in Australia. Indeed, there has been insufficient quantitative assessment of the impacts to even determine what is required to ensure a comprehensive, adequate and representative protection of these freshwater ecosystems. To underpin the sustainability of inland recreational fishing in the country, it was concluded that research is required to underpin the development and implementation of appropriate policies. The alternative is that the

Trophic transfer of metal nanoparticles in freshwater ecosystems

DEFF Research Database (Denmark)

Tangaa, Stine Rosendal

freshwater ecosystems range from a few ng/L in surface waters and up to mg/kg in sediments. Several studies have shown Ag ENPs to be toxic, bioaccumulative and harmful to aquatic biota within these concentration ranges. However, research on potential trophic transfer of Ag ENPs is limited. To investigate...... the aquatic ecosystems, Ag ENPs will undergo several transformation processes, ultimately leading to particles settling out of the water column. This will likely result in an increased concentration of ENPs in the sediment. In fact, predicted environmental concentrations of Ag ENPs in Danish and European...... freshwater food web. Future studies should concentrate on the internal distribution of Me-ENPs after uptake in both prey and predator, as this will increase the understanding of fate and effects of Me-ENPs on aquatic biota. Trophic transfer studies including more trophic levels, and higher pelagic organisms...

How close do we live to water? A global analysis of population distance to freshwater bodies.

Directory of Open Access Journals (Sweden)

Matti Kummu

Full Text Available Traditionally, people have inhabited places with ready access to fresh water. Today, over 50% of the global population lives in urban areas, and water can be directed via tens of kilometres of pipelines. Still, however, a large part of the world's population is directly dependent on access to natural freshwater sources. So how are inhabited places related to the location of freshwater bodies today? We present a high-resolution global analysis of how close present-day populations live to surface freshwater. We aim to increase the understanding of the relationship between inhabited places, distance to surface freshwater bodies, and climatic characteristics in different climate zones and administrative regions. Our results show that over 50% of the world's population lives closer than 3 km to a surface freshwater body, and only 10% of the population lives further than 10 km away. There are, however, remarkable differences between administrative regions and climatic zones. Populations in Australia, Asia, and Europe live closest to water. Although populations in arid zones live furthest away from freshwater bodies in absolute terms, relatively speaking they live closest to water considering the limited number of freshwater bodies in those areas. Population distributions in arid zones show statistically significant relationships with a combination of climatic factors and distance to water, whilst in other zones there is no statistically significant relationship with distance to water. Global studies on development and climate adaptation can benefit from an improved understanding of these relationships between human populations and the distance to fresh water.

Venomics and antivenomics of Bothrops erythromelas from five geographic populations within the Caatinga ecoregion of northeastern Brazil.

Science.gov (United States)

Jorge, Roberta Jeane B; Monteiro, Helena S A; Gonçalves-Machado, Larissa; Guarnieri, Míriam C; Ximenes, Rafael M; Borges-Nojosa, Diva M; Luna, Karla P de O; Zingali, Russolina B; Corrêa-Netto, Carlos; Gutiérrez, José María; Sanz, Libia; Calvete, Juan J; Pla, Davinia

2015-01-30

The Caatinga lancehead, Bothrops erythromelas, is a medically relevant species, responsible for most of the snakebite accidents in most parts of its distribution range in northeastern Brazil. The spectrum and geographic variability of its venom toxins were investigated applying a venomics approach to venom pools from five geographic areas within the Caatinga ecoregion. Despite its wide habitat, populations of B. erythromelas from Ceará, Pernambuco, Juazeiro, Paraiba, and Ilha de Itaparica exhibit highly conserved venom proteomes. Mirroring their compositional conservation, the five geographic venom pools also showed qualitatively and quantitatively overlapping antivenomic profiles against antivenoms generated in Vital Brazil (BR) and Clodomiro Picado (CR) Institutes, using different venoms in the immunization mixtures. The paraspecificity exhibited by the Brazilian SAB and the Costa Rican BCL antivenoms against venom toxins from B. erythromelas indicates large immunoreactive epitope conservation across genus Bothrops during the last ~14 million years, thus offering promise for the possibility of generating a broad-spectrum bothropic antivenom. Biological Significance Accidental snakebite envenomings represent an important public health hazard in Brazil. Ninety per cent of the yearly estimated 20-30,000 snakebite accidents are caused by species of the Bothrops genus. Bothrops erythromelas, a small, moderately stocky terrestrial venomous snake, is responsible for most of the snakebite accidents in its broad distribution range in the Caatinga, a large ecoregion in northeastern Brazil. To gain a deeper insight into the spectrum of medically important toxins present in the venom of the Caatinga lancehead, we applied a venomics approach to define the proteome and geographic variability of adult B. erythromelas venoms from five geographic regions. Although intraspecific compositional variation between venoms among specimens from different geographic regions has long been

Novel Synechococcus genomes reconstructed from freshwater reservoirs

Czech Academy of Sciences Publication Activity Database

Cabello-Yeves, P.J.; Haro-Moreno, J.M.; Martin-Cuadrado, A.B.; Ghai, Rohit; Picazo, A.; Camacho, A.; Rodriguez-Valera, F.

2017-01-01

Roč. 8, June (2017), č. článku 1151. ISSN 1664-302X R&D Projects: GA ČR(CZ) GA17-04828S Institutional support: RVO:60077344 Keywords : Synechococcus * picocyanobacteria * freshwater reservoirs * metagenomics * abundance Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.076, year: 2016

A NEW FRESHWATER GOBY (TELEOSTEI: GOBIIDAE) FROM THE ...

African Journals Online (AJOL)

497. JUDB, R. A. 1967. Freshwater fishes of southern Africa. Cape Town: Balkema. KOUMANS, F. P. 1931. A preliminary revision of the genera of the gobioidfishes with united ventral fins. N. V. Lisse. (Netherlands) 1-174: Drukkerij, Imperator. R.

Factors driving changes in freshwater mussel (Bivalvia, Unionida) diversity and distribution in Peninsular Malaysia.

Science.gov (United States)

Zieritz, Alexandra; Lopes-Lima, Manuel; Bogan, Arthur E; Sousa, Ronaldo; Walton, Samuel; Rahim, Khairul Adha A; Wilson, John-James; Ng, Pei-Yin; Froufe, Elsa; McGowan, Suzanne

2016-11-15

Freshwater mussels (Bivalvia, Unionida) fulfil important ecosystem functions and are one of the most threatened freshwater taxa globally. Knowledge of freshwater mussel diversity, distribution and ecology in Peninsular Malaysia is extremely poor, and the conservation status of half of the species presumed to occur in the region has yet to be assessed. We conducted the first comprehensive assessment of Peninsular Malaysia's freshwater mussels based on species presence/absence and environmental data collected from 155 sites spanning all major river catchments and diverse habitat types. Through an integrative morphological-molecular approach we recognised nine native and one widespread non-native species, i.e. Sinanodonta woodiana. Two species, i.e. Pilsbryoconcha compressa and Pseudodon cambodjensis, had not been previously recorded from Malaysia, which is likely a result of morphological misidentifications of historical records. Due to their restriction to single river catchments and declining distributions, Hyriopsis bialata, possibly endemic to Peninsular Malaysia, Ensidens ingallsianus, possibly already extinct in the peninsula, and Rectidens sumatrensis, particularly require conservation attention. Equally, the Pahang, the Perak and the north-western river catchments are of particular conservation value due to the presence of a globally unique freshwater mussel fauna. Statistical relationships of 15 water quality parameters and mussel presence/absence identified acidification and nutrient pollution (eutrophication) as the most important anthropogenic factors threatening freshwater mussel diversity in Peninsular Malaysia. These factors can be linked to atmospheric pollution, deforestation, oil-palm plantations and a lack of functioning waste water treatment, and could be mitigated by establishing riparian buffers and improving waste water treatment for rivers running through agricultural and residential land. Copyright © 2016 Elsevier B.V. All rights reserved.

Global diversity patterns of freshwater fishes - potential victims of their own success

OpenAIRE

Pelayo-Villamil, P.; Guisande, C.; Vari, R. P.; Manjarres-Hernandez, A.; Garcia-Rosello, E.; Gonzalez-Dacosta, J.; Heine, J.; Vilas, L. G.; Patti, B.; Quinci, E. M.; Jimenez, L. F.; Granado-Lorencio, C.; Tedesco, Pablo; Lobo, J. M.

2015-01-01

AimTo examine the pattern and cumulative curve of descriptions of freshwater fishes world-wide, the geographical biases in the available information on that fauna, the relationship between species richness and geographical rarity of such fishes, as well as to assess the relative contributions of different environmental factors on these variables. LocationGlobal. MethodsModestR was used to summarize the geographical distribution of freshwater fish species using information available from data-...

FRESHWATER FISH FARMING CONDITIONS IN 1999 AND THE PRODUCTION PLAN FOR 2000

Directory of Open Access Journals (Sweden)

Zlatko Homen

2000-09-01

Full Text Available One of the activities of the Ministry of Agriculture and Forestry, Fishery and Mediterranean Agriculture Directorate, i. e. Fishery Directorate to be more specific, is the monitoring of conditions in freshwater fish farming. The objective of this work is to show conditions in freshwater fish farming during 1999. and to provide a production plan for 2000. It will also provide detailed insight into the present conditions in freshwater fish farming and into the production trends of this field. Regarding this issue, the »Questionnaire for the Monitoring of Conditions in Freshwater Fish Farming«, was sent to fish farmers aroud the country data was processed from 22 cap ponds and 13 trout ponds. Roughe estimates of conditions were conducted for 2 fish farms, since they haven’t yet returned the mandatoruy questionnaire, i. e. the necessary data. This work features data on the number of employees in fish farms, as well as their qualifications, on the actual production and distribution of farmed freshwater fish, on the areas where production was conducted and on the overall yield. Fish food, raw materials, used tools and incentive funds paid were also taken into consideration. The difficulties faced in this branch of the economy are also inicated. Compared to 1998, a slight decrease in the number of employees of freshwater fish farms has been recorded. The total number of employees in 1999 was 655, of which 555 were on carp ponds and 100 on trout ponds. Data on the qualifications of employees for 1999 show that most of them were unskilled workers, while highly skilled workers make up a minority in this work force. The total production of freshwater in 1999. amoounted to 6.185,51 tons. Of this amount 5.592,52 tons were warm-water fish specied and 592,99 tons were cold-water fish species. Compared to 1998, production decreased by 4,89 percent. Production for 2000 has been planned to increase by 22,15 percent, i. e. the production quantity is projected

Functional integrity of freshwater forested wetlands, hydrologic alteration, and climate change

Science.gov (United States)

Middleton, Beth A.; Souter, Nicholas J.;

2016-01-01

Climate change will challenge managers to balance the freshwater needs of humans and wetlands. The Intergovernmental Panel on Climate Change predicts that most regions of the world will be exposed to higher temperatures, CO2, and more erratic precipitation, with some regions likely to have alternating episodes of intense flooding and mega-drought. Coastal areas will be exposed to more frequent saltwater inundation as sea levels rise. Local land managers desperately need intra-regional climate information for site-specific planning, management, and restoration activities. Managers will be challenged to deliver freshwater to floodplains during climate change-induced drought, particularly within hydrologically altered and developed landscapes. Assessment of forest health, both by field and remote sensing techniques, will be essential to signal the need for hydrologic remediation. Studies of the utility of the release of freshwater to remediate stressed forested floodplains along the Murray and Mississippi Rivers suggest that brief episodes of freshwater remediation for trees can have positive health benefits for these forests. The challenges of climate change in forests of the developing world will be considered using the Tonle Sap of Cambodia as an example. With little ecological knowledge of the impacts, managing climate change will add to environmental problems already faced in the developing world with new river engineering projects. These emerging approaches to remediate stressed trees will be of utmost importance for managing worldwide floodplain forests with predicted climate changes.

Calanoid Copepod Behavior in Thin Layer Shear Flows: Freshwater Versus Marine

Science.gov (United States)

Skipper, A. N.; Webster, D. R.; Yen, J.

2015-11-01

Marine copepods have been shown to behaviorally respond to vertical gradients of horizontal velocity and aggregate around thin layers. The current study addresses whether a freshwater copepod from an alpine lake demonstrates similar behavior response. Hesperodiaptomus shoshone is often the greatest biomass in alpine lakes and is the dominant zooplankton predator within its environment. The hypothesis is that H. shoshone responds to vertical gradients of horizontal velocity, which are associated with river outflows from alpine lakes, with fine-scale changes in swimming kinematics. The two calanoid copepods studied here, H. shoshone (freshwater) and Calanus finmarchicus(marine), are of similar size (2 - 4 mm), have similar morphologies, and utilize cruising as their primary swimming mode. The two animals differ not only in environment, but also in diet; H. shoshone is a carnivore, whereas C. finmarchicusis an herbivore. A laminar, planar jet (Bickley) was used in the laboratory to simulate a free shear flow. Particle image velocimetry (PIV) quantified the flow field. The marine species changed its swimming behavior significantly (increased swimming speed and turning frequency) and spent more time in the layer (40% vs. 70%) from control to treatment. In contrast, the freshwater species exhibited very few changes in either swimming behavior or residence time. Swimming kinematics and residence time results were also similar between males and females. Unlike the marine copepod, the results suggest the environmental flow structure is unimportant to the freshwater species.

Impact of transient freshwater releases in the Southern Ocean on the AMOC and climate

Energy Technology Data Exchange (ETDEWEB)

Swingedouw, Didier [Universite Catholique de Louvain, Institut d' Astronomie et de Geophysique Georges Lemaitre, Louvain-la-Neuve (Belgium); CERFACS/GlobC, Toulouse (France); Fichefet, T.; Goosse, H.; Loutre, M.F. [Universite Catholique de Louvain, Institut d' Astronomie et de Geophysique Georges Lemaitre, Louvain-la-Neuve (Belgium)

2009-08-15

The bipolar ocean seesaw is a process that explains the competition between deep waters formed in the North Atlantic (NA) and in the Southern Ocean (SO). In this picture, an increase in the rate of formation of one of these water masses is made at the expense of the other. However, recent studies have questioned the effectiveness of this process. Namely, they show that adding freshwater in the SO can reduce deep water formation in the SO as well as in the NA. In this study, we explore the mechanisms and time scales excited by such a SO freshwater release by performing sensitivity experiments where a freshwater input is added abruptly in the ocean, south of 60 S, with different rates and durations. For this purpose, we evaluate the separate effects of wind, temperature and salinity changes, and we put the emphasis on the time evolution of the system. We find three main processes that respond to these freshwater inputs and affect the NA Deep Water (NADW) production: (i) the deep water adjustment, which enhances the NADW cell, (ii) the salinity anomaly spread from the SO, which weakens the NADW cell, and (iii) the increase in the Southern Hemisphere wind stress, which enhances the NADW cell. We show that process (i) affects the Atlantic in a few years, due to an adjustment of the pycnocline depth through oceanic waves in response to the buoyancy perturbation in the SO. The salinity anomalies responsible for the NADW production decrease [process (ii)] invades the NA in around 30 years, while the wind stress from process (iii) increases in around 20 years after the beginning of the freshwater perturbation. Finally, by testing the response of the ocean to a large range of freshwater release fluxes, we show that for fluxes larger than 0.2 Sv, process (ii) dominates over the others and limits NADW production after a few centuries, while for fluxes lower than 0.2 Sv, process (ii) hardly affects the NADW production. On the opposite, the NADW export is increased by processes

Effects of pollution on freshwater fish and amphibians

International Nuclear Information System (INIS)

Pickering, Q.H.; Hunt, E.P.; Phipps, G.L.; Roush, T.H.; Smith, W.E.; Spehar, D.L.; Stephan, C.E.; Tanner, D.K.

1983-01-01

A literature review is presented dealing with studies on the effects of pollution on freshwater fish and amphibians. The pollutants studied included acid mine drainage, PCBs, cadmium, lead, naphthalene, plutonium, in addition to several studies dealing with pH effects

Reducing the impact of irrigated crops on freshwater availability: the case of Brazilian yellow melons

NARCIS (Netherlands)

Brito de Figueirêdo, M.C.; Boer, de I.J.M.; Kroeze, C.; Silva Barros, da V.; Sousa, de J.A.; Souza de Aragão, F.A.; Sonsol Gondim, R.; Potting, J.

2014-01-01

Purpose This study quantifies freshwater consumption throughout the life cycle of Brazilian exported yellow melons and assesses the resulting impact on freshwater availability. Results are used to identify improvement options. Moreover, the study explores the further impact of variations in

Dactylobiotus luci , a new freshwater tardigrade (Eutardigrada ...

African Journals Online (AJOL)

A new freshwater eutardigrade, Dactylobiotus luci sp. nov., is described from a permanent marsh pool (Zaphania's Pool) at 4225 m elevation in the Alpine zone of the Rwenzori Mountains, Uganda. The new species is most similar to D. dervizi Biserov, 1998 in the shape of the egg processes, absence of papillae and ...

Conservation status of freshwater gastropods of Canada and the United States

Science.gov (United States)

Johnson, Paul D.; Bogan, Arthur E.; Brown, Kenneth M.; Burkhead, Noel M.; Cordeiro, James R.; Garner, Jeffrey T.; Hartfield, Paul D.; Lepitzki, Dwayne A.; Mackie, Gerry L.; Pip, Eva; Tarpley, Thomas A.; Tiemann, Jeremy S.; Whelan, Nathan V.; Strong, Ellen E.

2013-01-01

This is the first American Fisheries Society conservation assessment of freshwater gastropods (snails) from Canada and the United States by the Gastropod Subcommittee (Endangered Species Committee). This review covers 703 species representing 16 families and 93 genera, of which 67 species are considered extinct, or possibly extinct, 278 are endangered, 102 are threatened, 73 are vulnerable, 157 are currently stable, and 26 species have uncertain taxonomic status. Of the entire fauna, 74% of gastropods are imperiled (vulnerable, threatened, endangered) or extinct, which exceeds imperilment levels in fishes (39%) and crayfishes (48%) but is similar to that of mussels (72%). Comparison of modern to background extinction rates reveals that gastropods have the highest modern extinction rate yet observed, 9,539 times greater than background rates. Gastropods are highly susceptible to habitat loss and degradation, particularly narrow endemics restricted to a single spring or short stream reaches. Compilation of this review was hampered by a paucity of current distributional information and taxonomic uncertainties. Although research on several fronts including basic biology, physiology, conservation strategies, life history, and ecology are needed, systematics and curation of museum collections and databases coupled with comprehensive status surveys (geographic limits, threat identification) are priorities.

Effects of acidification on olfactory-mediated behaviour in freshwater and marine ecosystems: a synthesis.

Science.gov (United States)

Leduc, Antoine O H C; Munday, Philip L; Brown, Grant E; Ferrari, Maud C O

2013-01-01

For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Whereas the ecological impacts of impaired olfactory-mediated behaviour may be similar between freshwater and marine ecosystems, the underlying mechanisms are quite distinct. In acidified freshwater, molecular change to chemical cues along with reduced olfaction sensitivity appear to be the primary causes of olfactory-mediated behavioural impairment. By contrast, experiments simulating future ocean acidification suggest that interference of high CO2 with brain neurotransmitter function is the primary cause for olfactory-mediated behavioural impairment in fish. Different physico-chemical characteristics between marine and freshwater systems are probably responsible for these distinct mechanisms of impairment, which, under globally rising CO2 levels, may lead to strikingly different consequences to olfaction. While fluctuations in pH may occur in both freshwater and marine ecosystems, marine habitat will remain alkaline despite future ocean acidification caused by globally rising CO2 levels. In this synthesis, we argue that ecosystem-specific mechanisms affecting olfaction need to be considered for effective management and conservation practices.

Bibliography on cycling of trace metals in freshwater ecosystems

International Nuclear Information System (INIS)

LaRiviere, M.G.; Scott, A.J.; Woodfield, W.G.; Cushing, C.E.

1978-07-01

This bibliography is a listing of pertinent literature directly addressing the cycling of trace metals in freshwater ecosystems. Data on cycling, including the influences of environmental mediators, are included. 151 references

An overview of freshwater prawn fishery in Bangladesh: present status and future prospect

Directory of Open Access Journals (Sweden)

Ferdous Ahamed

2014-07-01

Full Text Available The freshwater prawn fishery plays an important role in the economy of Bangladesh. The fishery is mainly based on the culture of Macrobrachium rosenbergii. The culture fishery has been growing rapidly, thus, masking the dwindling capture fishery which is faced with serious environmental issues augmented by deleterious fishing methods. Despite the high prospects of the freshwater prawn aquaculture in Bangladesh, a lot of research is needed to ensure the sustainable development of the capture fishery which forms a key source of prawn aquaculture seed as well as provide a baseline for future appraisals. Freshwater prawn aquaculture in Bangladesh is based on traditional methods with continuous adaptations by the rural fishers. However, numerous constraints to its full development are evident at all stages of its production. Lack of quality brood stock, seed, feeds and poor technical knowledge at farmers level are but some of the impediments challenging the sustainability of this industry. This paper reviews the freshwater prawn fishery of Bangladesh over the last few decades and outlines approaches for the development of an ecosystem-based management of both the culture and capture sectors of this important fishery.

Evaluation of Drought Implications on Ecosystem Services: Freshwater Provisioning and Food Provisioning in the Upper Mississippi River Basin.

Science.gov (United States)

Li, Ping; Omani, Nina; Chaubey, Indrajeet; Wei, Xiaomei

2017-05-08

Drought is one of the most widespread extreme climate events with a potential to alter freshwater availability and related ecosystem services. Given the interconnectedness between freshwater availability and many ecosystem services, including food provisioning, it is important to evaluate the drought implications on freshwater provisioning and food provisioning services. Studies about drought implications on streamflow, nutrient loads, and crop yields have been increased and these variables are all process-based model outputs that could represent ecosystem functions that contribute to the ecosystem services. However, few studies evaluate drought effects on ecosystem services such as freshwater and food provisioning and quantify these services using an index-based ecosystem service approach. In this study, the drought implications on freshwater and food provisioning services were evaluated for 14 four-digit HUC (Hydrological Unit Codes) subbasins in the Upper Mississippi River Basin (UMRB), using three drought indices: standardized precipitation index ( SPI ), standardized soil water content index ( SSWI ), and standardized streamflow index ( SSI ). The results showed that the seasonal freshwater provisioning was highly affected by the precipitation deficits and/or surpluses in summer and autumn. A greater importance of hydrological drought than meteorological drought implications on freshwater provisioning was evident for the majority of the subbasins, as evidenced by higher correlations between freshwater provisioning and SSI 12 than SPI 12. Food provisioning was substantially affected by the precipitation and soil water deficits during summer and early autumn, with relatively less effect observed in winter. A greater importance of agricultural drought effects on food provisioning was evident for most of the subbasins during crop reproductive stages. Results from this study may provide insights to help make effective land management decisions in responding to

Modeling the influence of atmospheric leading modes on the variability of the Arctic freshwater cycle

Science.gov (United States)

Niederdrenk, L.; Sein, D.; Mikolajewicz, U.

2013-12-01

Global general circulation models show remarkable differences in modeling the Arctic freshwater cycle. While they agree on the general sinks and sources of the freshwater budget, they differ largely in the magnitude of the mean values as well as in the variability of the freshwater terms. Regional models can better resolve the complex topography and small scale processes, but they are often uncoupled, thus missing the air-sea interaction. Additionally, regional models mostly use some kind of salinity restoring or flux correction, thus disturbing the freshwater budget. Our approach to investigate the Arctic hydrologic cycle and its variability is a regional atmosphere-ocean model setup, consisting of the global ocean model MPIOM with high resolution in the Arctic coupled to the regional atmosphere model REMO. The domain of the atmosphere model covers all catchment areas of the rivers draining into the Arctic. To account for all sinks and sources of freshwater in the Arctic, we include a discharge model providing terrestrial lateral waterflows. We run the model without salinity restoring but with freshwater correction, which is set to zero in the Arctic. This allows for the analysis of a closed freshwater budget in the Artic region. We perform experiments for the second half of the 20th century and use data from the global model MPIOM/ECHAM5 performed with historical conditions, that was used within the 4th Assessment Report of the IPCC, as forcing for our regional model. With this setup, we investigate how the dominant modes of large-scale atmospheric variability impact the variability in the freshwater components. We focus on the two leading empirical orthogonal functions of winter mean sea level pressure, as well as on the North Atlantic Oscillation and the Siberian High. These modes have a large impact on the Arctic Ocean circulation as well as on the solid and liquid export through Fram Strait and through the Canadian archipelago. However, they cannot explain

Stability of single dispersed silver nanoparticles in natural and synthetic freshwaters: Effects of dissolved oxygen.

Science.gov (United States)

Zou, Xiaoyan; Li, Penghui; Lou, Jie; Fu, Xiaoyan; Zhang, Hongwu

2017-11-01

Silver nanoparticles (AgNPs) are increasingly used in various commercial products. This increased use raises ecological concerns because of the large release of AgNPs into the environment. Once released, the local water chemistry has the potential to influence the environmental fates and behaviors of AgNPs. The impacts of dissolved oxygen and natural organic matter (NOM) on the dissolution and stability of AgNPs were investigated in synthetic and natural freshwaters for 7 days. In synthetic freshwater, the aggregation of AgNPs occurred due to the compression of the electric double layer, accompanied by the dissolution of AgNPs. However, once oxygen was removed, the highest dissolved Ag (Ag dis ) concentration decreased from 356.5 μg/L to 272.1 μg/L, the pH of the AgNP suspensions increased from less than 7.6 to more than 8.4, and AgNPs were regenerated by the reduction of released Ag + by citrate. The addition of NOM mitigated aggregation, inhibited oxidative dissolution and induced the transformation of AgNPs into Ag 2 S due to the formation of NOM-adsorbed layers, the reduction of Ag + by NOM, and the high affinity of sulfur-enriched species in NOM for Ag. Likewise, in oxygen-depleted natural freshwaters, the inhibition of oxidative dissolution was obtained in comparison with oxygenated freshwaters, showing a decrease in the maximum Ag dis concentration from 137.6 and 57.0 μg/L to 83.3 and 42.4 μg/L from two natural freshwater sites. Our results suggested that aggregation and dissolution of AgNPs in aquatic environments depend on the chemical composition, where oxygen-depleted freshwaters more significantly increase the colloidal stability. In comparison with oxic conditions, anoxic conditions were more favorable to the regeneration of AgNPs by reducing species (e.g., citrate and NOM) and enhanced the stability of nanoparticles. This indicates that some AgNPs will be more stable for long periods in oxygen-deprived freshwaters, and pose more serious

Using species sensitivity distribution approach to assess the risks of commonly detected agricultural pesticides to Australia's tropical freshwater ecosystems.

Science.gov (United States)

Pathiratne, Asoka; Kroon, Frederieke J

2016-02-01

To assess the potential impacts of agricultural pesticides on tropical freshwater ecosystems, the present study developed temperature-specific, freshwater species protection concentrations (i.e., ecotoxicity threshold values) for 8 pesticides commonly detected in Australia's tropical freshwaters. Because relevant toxicity data for native tropical freshwater species to assess the ecological risks were mostly absent, scientifically robust toxicity data obtained at ≥20 °C were used for ecologically relevant taxonomic groups representing primary producers and consumers. Species sensitivity distribution (SSD) curves were subsequently generated for predicted chronic exposure using Burrlioz 2.0 software with mixed chronic and converted acute data relevant to exposure conditions at ≥20 °C. Ecotoxicity threshold values for tropical freshwater ecosystem protection were generated for ametryn, atrazine, diuron, metolachlor, and imidacloprid (all moderate reliability), as well as simazine, hexazinone, and tebuthiuron (all low reliability). Using these SSD curves, the retrospective risk assessments for recently reported pesticide concentrations highlight that the herbicides ametryn, atrazine, and diuron are of major concern for ecological health in Australia's tropical freshwater ecosystems. The insecticide imidacloprid also appears to pose an emerging threat to the most sensitive species in tropical freshwater ecosystems. The exposed temperature-specific approach may be applied to develop water quality guideline values for other environmental contaminants detected in tropical freshwater ecosystems until reliable and relevant toxicity data are generated using representative native species. © 2015 SETAC.

Sensitivity ranking for freshwater invertebrates towards hydrocarbon contaminants.

Science.gov (United States)

Gerner, Nadine V; Cailleaud, Kevin; Bassères, Anne; Liess, Matthias; Beketov, Mikhail A

2017-11-01

Hydrocarbons have an utmost economical importance but may also cause substantial ecological impacts due to accidents or inadequate transportation and use. Currently, freshwater biomonitoring methods lack an indicator that can unequivocally reflect the impacts caused by hydrocarbons while being independent from effects of other stressors. The aim of the present study was to develop a sensitivity ranking for freshwater invertebrates towards hydrocarbon contaminants, which can be used in hydrocarbon-specific bioindicators. We employed the Relative Sensitivity method and developed the sensitivity ranking S hydrocarbons based on literature ecotoxicological data supplemented with rapid and mesocosm test results. A first validation of the sensitivity ranking based on an earlier field study has been conducted and revealed the S hydrocarbons ranking to be promising for application in sensitivity based indicators. Thus, the first results indicate that the ranking can serve as the core component of future hydrocarbon-specific and sensitivity trait based bioindicators.

A synthetic phylogeny of freshwater crayfish: insights for conservation

Science.gov (United States)

Owen, Christopher L.; Bracken-Grissom, Heather; Stern, David; Crandall, Keith A.

2015-01-01

Phylogenetic systematics is heading for a renaissance where we shift from considering our phylogenetic estimates as a static image in a published paper and taxonomies as a hardcopy checklist to treating both the phylogenetic estimate and dynamic taxonomies as metadata for further analyses. The Open Tree of Life project (opentreeoflife.org) is developing synthesis tools for harnessing the power of phylogenetic inference and robust taxonomy to develop a synthetic tree of life. We capitalize on this approach to estimate a synthesis tree for the freshwater crayfish. The crayfish make an exceptional group to demonstrate the utility of the synthesis approach, as there recently have been a number of phylogenetic studies on the crayfishes along with a robust underlying taxonomic framework. Importantly, the crayfish have also been extensively assessed by an IUCN Red List team and therefore have accurate and up-to-date area and conservation status data available for analysis within a phylogenetic context. Here, we develop a synthesis phylogeny for the world's freshwater crayfish and examine the phylogenetic distribution of threat. We also estimate a molecular phylogeny based on all available GenBank crayfish sequences and use this tree to estimate divergence times and test for divergence rate variation. Finally, we conduct EDGE and HEDGE analyses and identify a number of species of freshwater crayfish of highest priority in conservation efforts. PMID:25561670

[Freshwater malacofauna of medical importance located in Yaguajay municipality, Sancti Spíritus province].

Science.gov (United States)

Fimia Duarte, Rigoberto; Vázquez Perera, Antonio A; Luis Rodríguez, Yuodenis; Cepero Rodriguez, Omelio; Pereira Marin, Carlos A

2010-01-01

the study carried out in Yaguajay, Sancti Spíritus province was aimed at identifying the mollusk species present in the freshwater ecocystems as well as their distribution and abundance in each reservoir. two years--2005 and 2006--were analyzed through 2 samplings per years covering the rainy and the dry season; 20 reservoirs were sampled to determine the present freshwater mollusks. Data were processed by Excelxp and the statistical analysis used SPSS version 8 processor and 4 x 4 contingency tables. ten species were detected in 2005, being Tarebia granifera the most distributed and abundant followed by Marisa cornuarietis. It was observed that the highest amount of mosquitoes was collected in the rainy season during the two years under study in addition to proving that there was significant correlation between the occurrence of mollusk species and fish in the 20 researched reservoirs. Yaguajay municipality exhibits wide freshwater mollusk fauna if one takes into account the 14 identified species of which 4 turned out to be intermediate hosts for fascioliasis, schistosomiasis and angiostrongyliasis. There is close relation between freshwater malacofauna and vegetation.

Tropical Freshwater Biology - Vol 18, No 2 (2009)

African Journals Online (AJOL)

Organic fertilizer decomposition and nutrient loads in water reservoir with changing temperature, Wakiso – Ug · EMAIL FULL TEXT EMAIL FULL TEXT ... benthos in response to the biodeposition and bioturbation activities of the freshwater mussel Lamellidens marginalis (Lamarck) · EMAIL FULL TEXT EMAIL FULL TEXT

Anaemia in the freshwater catfish Clarias albopunctatus (Teleostei ...

African Journals Online (AJOL)

Haematological changes were studied in freshwater catfish Clarias albopunctatus exposed for 20 days to 25%, 50% and 100% concentrations of brewery wastewater prepared by dilution using tap water. Haemoglobin, haematocrit and erythrocyte counts in fish exposed to wastewater were significantly lower than in a ...

Haff disease associated with the ingestion of the freshwater fish Mylossoma duriventre (pacu-manteiga).

Science.gov (United States)

Tolesani Júnior, Oswaldo; Roderjan, Christian Nejm; do Carmo Neto, Edgard; Ponte, Micheli Mikaeli; Seabra, Mariana Cristina Pelli; Knibel, Marcos Freitas

2013-01-01

Haff disease associated rhabdomyolysis is correlated with the ingestion of certain freshwater fish and shellfish and is caused by an unidentified toxin. We report the case of a patient who experienced rhabdomyolysis approximately 2 hours after ingestion of the freshwater fish Mylossoma duriventre (pacu-manteiga) approximately 3 years after an outbreak had been reported in Manaus, Brazilian Amazon.

A physically based model of global freshwater surface temperature

Science.gov (United States)

van Beek, Ludovicus P. H.; Eikelboom, Tessa; van Vliet, Michelle T. H.; Bierkens, Marc F. P.

2012-09-01

Temperature determines a range of physical properties of water and exerts a strong control on surface water biogeochemistry. Thus, in freshwater ecosystems the thermal regime directly affects the geographical distribution of aquatic species through their growth and metabolism and indirectly through their tolerance to parasites and diseases. Models used to predict surface water temperature range between physically based deterministic models and statistical approaches. Here we present the initial results of a physically based deterministic model of global freshwater surface temperature. The model adds a surface water energy balance to river discharge modeled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff, and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by shortwave and longwave radiation and sensible and latent heat fluxes. Also included are ice formation and its effect on heat storage and river hydraulics. We use the coupled surface water and energy balance model to simulate global freshwater surface temperature at daily time steps with a spatial resolution of 0.5° on a regular grid for the period 1976-2000. We opt to parameterize the model with globally available data and apply it without calibration in order to preserve its physical basis with the outlook of evaluating the effects of atmospheric warming on freshwater surface temperature. We validate our simulation results with daily temperature data from rivers and lakes (U.S. Geological Survey (USGS), limited to the USA) and compare mean monthly temperatures with those recorded in the Global Environment Monitoring System (GEMS) data set. Results show that the model is able to capture the mean monthly surface temperature for the majority of the GEMS stations, while the interannual variability as derived from the USGS and NOAA data was captured reasonably well. Results are poorest for

Freshwater autotrophic picoplankton: a review

Directory of Open Access Journals (Sweden)

John G. STOCKNER

2002-02-01

Full Text Available Autotrophic picoplankton (APP are distributed worldwide and are ubiquitous in all types of lakes of varying trophic state. APP are major players in carbon production in all aquatic ecosystems, including extreme environments such as cold ice-covered and/or warm tropical lakes and thermal springs. They often form the base of complex microbial food webs, becoming prey for a multitude of protozoan and micro-invertebrate grazers, that effectively channel APP carbon to higher trophic levels including fish. In this review we examine the existing literature on freshwater autotrophic picoplankton, setting recent findings and current ecological issues within an historic framework, and include a description of the occurrence and distribution of both single-cell and colonial APP (picocyanobacteria in different types of lakes. In this review we place considerable emphasis on methodology and ecology, including sampling, counting, preservation, molecular techniques, measurement of photosynthesis, and include extensive comment on their important role in microbial food webs. The model outlined by Stockner of an increase of APP abundance and biomass and a decrease of its relative importance with the increase of phosphorus concentration in lakes has been widely accepted, and only recently confirmed in marine and freshwater ecosystems. Nevertheless the relationship which drives the APP presence and importance in lakes of differing trophic status appears with considerable variation so we must conclude that the success of APP in oligotrophic lakes worldwide is not a certainty but highly probable.

Characterization of freshwater mosses as indicators of radioactive contamination

International Nuclear Information System (INIS)

Beaugelin-Seiller, K.

1994-01-01

The necessity of indicators of freshwater contamination has developed the interest for aquatic mosses. From a fundamental point of view, studying the influence of some biotic and abiotic factors has permitted to better know the mechanisms of radionuclides accumulation by these bryophytes. From a radioecological point of view, simulating real cases of water contamination has allowed to give results a very interesting representativeness. The use of mosses as bio-indicators was applied for two in situ experiments, the results of which have been interpreted from those obtained in laboratory. Finally, an approach by a mathematical model has showed that it is possible to have, in a middle term, an evaluation tool of freshwater contamination, based on the radionuclides concentrations measured in aquatic mosses. (author). refs., 57 figs., 24 tabs

Microplastics in freshwater systems: a review of the emerging threats, identification of knowledge gaps and prioritisation of research needs.

Science.gov (United States)

Eerkes-Medrano, Dafne; Thompson, Richard C; Aldridge, David C

2015-05-15

Plastic contamination is an increasing environmental problem in marine systems where it has spread globally to even the most remote habitats. Plastic pieces in smaller size scales, microplastics (particles microplastic presence and interactions are equally as far reaching as are being observed in marine systems. Microplastics are being detected in freshwaters of Europe, North America, and Asia, and the first organismal studies are finding that freshwater fauna across a range of feeding guilds ingest microplastics. Drawing from the marine literature and these initial freshwater studies, we review the issue of microplastics in freshwater systems to summarise current understanding, identify knowledge gaps and suggest future research priorities. Evidence suggests that freshwater systems may share similarities to marine systems in the types of forces that transport microplastics (e.g. surface currents); the prevalence of microplastics (e.g. numerically abundant and ubiquitous); the approaches used for detection, identification and quantification (e.g. density separation, filtration, sieving and infrared spectroscopy); and the potential impacts (e.g. physical damage to organisms that ingest them, chemical transfer of toxicants). Differences between freshwater and marine systems include the closer proximity to point sources in freshwaters, the typically smaller sizes of freshwater systems, and spatial and temporal differences in the mixing/transport of particles by physical forces. These differences between marine and freshwater systems may lead to differences in the type of microplastics present. For example, rivers may show a predictable pattern in microplastic characteristics (size, shape, relative abundance) based on waste sources (e.g. household vs. industrial) adjacent to the river, and distance downstream from a point source. Given that the study of microplastics in freshwaters has only arisen in the last few years, we are still limited in our understanding of 1

COMMERCIAL FRESHWATER FISHERIES IN REPUBLIC OF CROATIA IN 2009 AND 2010

Directory of Open Access Journals (Sweden)

Josip Suić

2011-12-01

Full Text Available Commercial freshwater fisheries in Republic of Croatia is regulated according to the Freshwater Fisheries Act (2001 and special sub-acts regarding commercial freshwater fisheries, as well as other sub-laws which deal with fish sizes, no-fishing periods and estimation of damages on fish stocks. Subjects of regulations are the areas for commercial fisheries, commercial fishermen exams, fishing permits, fishing tools and gear, yearly allowed catch quotas and catch data delivery. All the sub-acts are presented, as well the explanations of the key terminology and activities. The commercial fisheries catch data for 2009 were collected, analyzed and finally interacted to the yearly allowed catch quotas. According to the results of the analysis of particular interactions of catch/total catch, as well as the interaction between particular fish species and yearly allowed catch quotas, it is obvious that only the amount of carp catch on the Dunav in 2009 goes beyond the yearly allowed catch quota. According to the vast lack of inspectors, on local and state level as well, it is expected that after accepting of the new inspection regulations and competences, as well the lifting of the ban of recruiting state employees, it would be possible to ensure the more efficient surveillance and control of whole fisheries sector, also markets and restaurants. This will surely help decreasing of the black market. Also, according to the new Freshwater Fisheries Act, which is in the process of adoption, new regulations that relate to fish market will be accepted (landing places, first sell, first buyer.

Radurization of commercial freshwater fish species

International Nuclear Information System (INIS)

Chuaqui-Offermanns, N.; McDougall, T.E.; Sprung, W.; Sullivan, V.

1988-01-01

The effect of radurization on the shelf life of fresh Whitefish obtained through ordinary commercial channels has been determined. Whitefish fillets irradiated at 1.2 kGy and stored at 3 0 C have a shelf life three times longer than the unirradiated fish. When the fish was irradiated at 0.82 kGy a two fold shelf-life extension was obtained. The shelf life was estimated by sensory, chemical and microbiological evaluations. Sensory evaluation involved organoleptic assessment of raw and cooked samples. Since freshwater fish do not contain trimethylamine oxide (TMAO), alternate tests for freshness were required. It was found the determination of hypoxanthine and total volatile acid number (VAN) are excellent tests for freshness and quality of freshwater fish; thus, these analyses were adopted. The degree of radiation-induced lipid oxidation was measured by the thiobarbituric acid test (TBA). It was found at doses of 0.82 and 1.2 kGy the TBA number remained within acceptable limits in all samples. Microbiological analyses consisted of the total microbial load assessment in the sample, as well as Pseudomonas and total psychrotrophic counts. The estimated shelf lives as determined by the three separate evaluations were in very good agreement. (author)

Radurization of commercial freshwater fish species

Energy Technology Data Exchange (ETDEWEB)

Chuaqui-Offermanns, N.; McDougall, T.E.; Sprung, W.; Sullivan, V.

1988-01-01

The effect of radurization on the shelf life of fresh Whitefish obtained through ordinary commercial channels has been determined. Whitefish fillets irradiated at 1.2 kGy and stored at 3/sup 0/C have a shelf life three times longer than the unirradiated fish. When the fish was irradiated at 0.82 kGy a two fold shelf-life extension was obtained. The shelf life was estimated by sensory, chemical and microbiological evaluations. Sensory evaluation involved organoleptic assessment of raw and cooked samples. Since freshwater fish do not contain trimethylamine oxide (TMAO), alternate tests for freshness were required. It was found the determination of hypoxanthine and total volatile acid number (VAN) are excellent tests for freshness and quality of freshwater fish;thus, these analyses were adopted. The degree of radiation-induced lipid oxidation was measured by the thiobarbituric acid test (TBA). It was found at doses of 0.82 and 1.2 kGy the TBA number remained within acceptable limits in all samples. Microbiological analyses consisted of the total microbial load assessment in the sample, as well as Pseudomonas and total psychrotrophic counts. The estimated shelf lives as determined by the three separate evaluations were in very good agreement

First freshwater coralline alga and the role of local features in a major biome transition.

Science.gov (United States)

Žuljević, A; Kaleb, S; Peña, V; Despalatović, M; Cvitković, I; De Clerck, O; Le Gall, L; Falace, A; Vita, F; Braga, Juan C; Antolić, B

2016-01-21

Coralline red algae are significant components of sea bottom and up to now considered as exclusively marine species. Here we present the first coralline alga from a freshwater environment, found in the Cetina River (Adriatic Sea watershed). The alga is fully adapted to freshwater, as attested by reproductive structures, sporelings, and an inability to survive brackish conditions. Morphological and molecular phylogenetic analyses reveal the species belongs to Pneophyllum and is described as P. cetinaensis sp. nov. The marine-freshwater transition most probably occurred during the last glaciation. The brackish-water ancestor was preadapted to osmotic stress and rapid changes in water salinity and temperature. The particular characteristics of the karst Cetina River, such as hard water enriched with dissolved calcium carbonate and a pH similar to the marine environment, favoured colonization of the river by a marine species. The upstream advance and dispersal is facilitated by exceptionally pronounced zoochory by freshwater gastropods. Pneophyllum cetinaensis defies the paradigm of Corallinales as an exclusively marine group.

Perfluoroalkyl acid contamination and polyunsaturated fatty acid composition of French freshwater and marine fishes.

Science.gov (United States)

Yamada, Ami; Bemrah, Nawel; Veyrand, Bruno; Pollono, Charles; Merlo, Mathilde; Desvignes, Virginie; Sirot, Véronique; Oseredczuk, Marine; Marchand, Philippe; Cariou, Ronan; Antignac, Jean-Phillippe; Le Bizec, Bruno; Leblanc, Jean-Charles

2014-07-30

In this study, French marine and freshwater fish perfluoroalkyl acid (PFAA) contamination are presented along with their fatty acid (FA) composition to provide further elements for a risk/benefit balance of fish consumption to be assessed. The 29 most consumed marine fish species were collected in four metropolitan French coastal areas in 2004 to constitute composite samples. Geographical differences in terms of consumed species and contamination level were taken into account. Three hundred and eighty-seven composite samples corresponding to 16 freshwater fish species collected between 2008 and 2010 in the six major French rivers or their tributaries were selected among the French national agency for water and aquatic environments freshwater fish sample library. The raw edible parts were analyzed for FA composition and PFAA contamination. Results show that freshwater fishes are more contaminated by PFAAs than marine fishes and do not share the same contamination profile. Freshwater fish contamination is mostly driven by perfluorooctane sulfonate (PFOS) (75%), whereas marine fish contamination is split between perfluorooctanoic acid (PFOA) (24%), PFOS (20%), perfluorohexanoic acid (PFHxA) (15%), perfluoropentanoic acid (PFHpA) (11%), and perfluorobutanoic acid (PFBA) (11%). Common carp, pike-perch, European perch, thicklip grey mullet, and common roach presented the most unfavorable balance profile due to their high level of PFAAs and low level of n-3 long-chain polyunsaturated fatty acids (LC-PUFAs). These data could be used, if needed, in an updated opinion on fish consumption that takes into account PFAA contamination.

Distinct freshwater and seawater isoforms of Na+/K+-ATPase in gill chloride cells of Atlantic salmon

Science.gov (United States)

McCormick, Stephen D.; Regish, A.M.; Christensen, A.K.

2009-01-01

Gill Na(+)/K(+)-ATPase (NKA) in teleost fishes is involved in ion regulation in both freshwater and seawater. We have developed and validated rabbit polyclonal antibodies specific to the NKA alpha1a and alpha1b protein isoforms of Atlantic salmon (Salmo salar Linnaeus), and used western blots and immunohistochemistry to characterize their size, abundance and localization. The relative molecular mass of NKA alpha1a is slightly less than that for NKA beta1b. The abundance of gill NKA alpha1a was high in freshwater and became nearly undetectable after seawater acclimation. NKA alpha1b was present in small amounts in freshwater and increased 13-fold after seawater acclimation. Both NKA isoforms were detected only in chloride cells. NKA alpha1a was located in both filamental and lamellar chloride cells in freshwater, whereas in seawater it was present only as a faint background in filamental chloride cells. In freshwater, NKA alpha1b was found in a small number of filamental chloride cells, and after seawater acclimation it was found in all chloride cells on the filament and lamellae. Double simultaneous immunofluorescence indicated that NKA alpha1a and alpha1b are located in different chloride cells in freshwater. In many chloride cells in seawater, NKA alpha1b was present in greater amounts in the subapical region than elsewhere in the cell. The combined patterns in abundance and immunolocalization of these two isoforms can explain the salinity-related changes in total NKA and chloride cell abundance. The results indicate that there is a freshwater and a seawater isoform of NKA alpha-subunit in the gills of Atlantic salmon and that they are present in distinct chloride cells.

Culture, hydrology, and other situational controls on atoll freshwater availability (Majuro, Republic of the Marshall Islands)

Science.gov (United States)

Shuster, W.

2016-12-01

The comparatively uncertain rainfall catch and rising seas in isolated North Pacific atoll communities has presented serious challenges to maintain human communities with freshwater volume. Moreover, the feudal hierarchy, which structures social and economic relationships among local governance and citizens contributes equally to problems and potential solutions. These relationships modulate the availability of critical ecosystem services generated by freshwater, with additional constraints contributed by climate change, rainfall variability (e.g., current El Niño climate pattern), and continuous threat of drought. The major freshwater resources for an atoll are the groundwater freshwater lens, residential and commercial rainwater harvesting, large-scale rainfall catchments (e.g., an airport runway), imported-virtual water, or desalinization subsidies. The significance of each of these resources scale across different atolls according to size, topography, soils, population, infrastructure, and land ownership. The potential integration and coordination of these water resources is largely unrealized due to land ownership, the lack of a contiguous catchment area, uneven and fractured governance. The situational aspects are further characterized by feuding among families and communities (some resource rich, some resource poor), and conflicting land use priorities where agriculture placement and practice can compromise the quality of already limited freshwater resources. This presentation uses the example of Majuro atoll (Republic of the Marshall Islands), field data and other observations, to illustrate sociohydrologic-drivers of freshwater availability, and suggests approaches that may improve on current and ongoing threats to public health and well-being.

The filter feeder Dreissena polymorpha affects nutrient, silicon, and metal(loid) mobilization from freshwater sediments.

Science.gov (United States)

Schaller, Jörg; Planer-Friedrich, Britta

2017-05-01

Organic sediments in aquatic ecosystems are well known sinks for nutrients, silicon, and metal(loid)s. Organic matter-consuming organisms like invertebrate shredders, grazers, and bioturbators significantly affect element fixation or remobilization by changing redox conditions or binding properties of organic sediments. Little is known about the effect of filter feeders, like the zebra mussel Dreissena polymorpha, an invasive organism in North American and European freshwater ecosystems. A laboratory batch experiment exposing D. polymorpha (∼1200 organisms per m 2 ) to organic sediment from a site contaminated with arsenic, copper, lead, and uranium revealed a significant uptake and accumulation of arsenic, copper, iron, and especially uranium both into the soft body tissues and the seashell. This is in line with previous observations of metal(loid) accumulation from biomonitoring studies. Regarding its environmental impact, D. polymorpha significantly contributed to mobilization of silicon, iron, phosphorus, arsenic, and copper and to immobilization of uranium (p < 0.001), probably driven by redox conditions, microbial activity within the gut system, or active control of element homeostasis. No net mobilization or immobilization was observed for zinc and lead, because of their low mobility at the prevailing pH of 7.5-8.5. The present results suggest that D. polymorpha can both ameliorate (nutrient mobilization, immobilization of toxicants mobile under oxic conditions) or aggravate negative effects (mobilization of toxicants mobile under reducing conditions) in ecosystems. Relating the results of the present study to observed population densities in natural freshwater ecosystems suggests a significant influence of D. polymorpha on element cycling and needs to be considered in future studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Radioecological studies of freshwater mollusks in the Chernobyl accident exclusion zone].

Science.gov (United States)

Gudkov, D I; Nazarov, A B; Dziubenko, E V; Kaglian, A E; Klenus, V G

2009-01-01

Species-specificity and dynamics of 90Sr, 137Cs and some transuranic elements accumulation in bivalve and gastropod freshwater molluscs of the Chernobyl exclusion zone during 1997-2008 was analyzed. The results of radiation dose and chromosome aberration rate estimation and the analysis of hemolymph composition of freshwater snail (Lymnaea stagnalis L.) was produced. The absorbed dose rate was registered in the range of 0.3-85.0 microGy/h. In closed water bodies the heightened chromosome aberration rate (up to 27%) in embryo tissues, and also the change of haematological indexes for the adult individuals of snails was registered.

Freshwater invertebrates of sub-Antarctic Marion Island | Dartnall ...

African Journals Online (AJOL)

The aquatic species include five platyhelminthes, a gastrotrich, three tardigrades, 28 rotifers, six nematodes, two annelids and 11 arthropods. Most are familiar species that have been recorded on other sub-Antarctic islands. The invertebrate faunas of the various freshwater habitats were basically similar in species ...

Physical modeling of the effects of climate change on freshwater lenses

Science.gov (United States)

Stoeckl, L.; Houben, G.

2012-04-01

The investigation of the fragile equilibrium between fresh and saline water on oceanic islands is of major importance for a sustainable management and protection of freshwater lenses. Overexploitation will lead to salt water intrusion (up-coning), in turn causing damages or even destruction of a lens in the long term. We have performed a series of experiments on the laboratory scale to investigate and visualize processes of freshwater lenses under different boundary conditions. In addition these scenarios were numerically simulated using the finite-element model FEFLOW. Results were also compared to analytical solutions for problems regarding e.g. mean travel times of flow paths within a freshwater lens. On the laboratory scale, a cross section of an island was simulated by setting up a sand-box model (200 cm x 50 cm x 5 cm). Lens dynamics are driven by density contrasts of saline and fresh water, recharge rate and Kf-values of the medium. We used a time-dependent, sequential application of the tracers uranine, eosine and indigotine, to represent different recharge events. With a stepwise increase of freshwater recharge, we could show that the maximum thickness of the lens increased in a non-linear behavior. Moreover we measured that the degradation of a freshwater lens after turning off the precipitation does not follow the same function as its development does. This means that a steady state freshwater lens does not degrade as fast as it develops under constant recharge. On the other side, we could show that this is not true for a partial degradation of the lens due to passing forces, like anthropogenic pumping or climate change. This is, because the recovery to equilibrium is always a quasi asymptotic process. Thus, times of re-equilibration to steady state will take longer after e.g. a drought, than the degradation during the draught itself. This behavior could also be verified applying the numerical finite-element model FEFLOW. In addition, numerical

The International Editorship of Freshwater Systems

OpenAIRE

Karl E. Havens

2001-01-01

It is my pleasure to announce that two distinguished internationalscientists have joined the editorship of the FreshwaterSystems domain of TheScientificWorldJOURNAL — Professor BrijGopal of Jawaharlal Nehru University (India) and Dr. Manual Gra柠of the Universityof Coimbra (Portugal). Professor Gopal is the Secretary General of the NationalInstitute of Ecology, Editor of the InternationalJournal of Ecology & Environmental Science,and Chairman of the SIL (International Association of Theoretica...

Fatty Acid Composition of Six Freshwater Wild Cyanobacterial Species

Czech Academy of Sciences Publication Activity Database

Řezanka, Tomáš; Dor, I.; Prell, Aleš; Dembitský, V. M.

2003-01-01

Roč. 48, č. 1 (2003), s. 71-75 ISSN 0015-5632 Institutional research plan: CEZ:AV0Z5020903 Keywords : cyanobacterial spcies * freshwater wild Subject RIV: EE - Microbiology, Virology Impact factor: 0.857, year: 2003

Conservation status and distribution of freshwater fishes in South ...

African Journals Online (AJOL)

Indigenous fishes include 43 species of the Zambezian faunal group (70% of the ... andrewi, Pseudobarbus afer) all of which are classified as Endangered. ... support only half of the freshwater fish species occurring in all national parks.

Occupational health issues in marine and freshwater research

Directory of Open Access Journals (Sweden)

Courtenay Glenn

2012-03-01

Full Text Available Abstract Marine and freshwater scientists are potentially exposed to a wide variety of occupational hazards. Depending on the focus of their research, risks may include animal attacks, physiological stresses, exposure to toxins and carcinogens, and dangerous environmental conditions. Many of these hazards have been investigated amongst the general population in their recreational use of the environment; however, very few studies have specifically related potential hazards to occupational exposure. For example, while the incidence of shark and crocodile attacks may invoke strong emotions and the occupational risk of working with these animals is certainly real, many more people are stung by jellyfish or bitten by snakes or dogs each year. Furthermore, a large proportion of SCUBA-related injuries and deaths are incurred by novice or uncertified divers, rather than professional divers using aquatic environments. Nonetheless, marine and freshwater research remains a potentially risky occupation, and the likelihood of death, injury and long-term health impacts still needs to be seriously considered.

Review of Ghana's water resources: the quality and management with particular focus on freshwater resources

Science.gov (United States)

Yeleliere, E.; Cobbina, S. J.; Duwiejuah, A. B.

2018-06-01

Freshwater resources are continually decreasing in quality and quantity. Approximately, 1% of this freshwater is accessible in lakes, river channels and underground for domestic use. The study reviewed literature on water resources with focus on freshwater, the quality of our freshwater in terms of physical, chemical and biological variables, the main mechanisms of management, and the challenges associated with these mechanisms as well as blending integrated water management with the indigenous or traditional management of water resources for sustainable development and peaceful co-existence. Also the review offered potent recommendations for policy makers to consider sustainable management of freshwater resources. A total of 95 articles were downloaded from Google scholar in water-related issues. The search took place from June to September 2017, and research articles from 1998 to 2018 were reviewed. Basically Ghana is made up of three discharge or outlet systems, namely the Coastal River Systems which is the least and Volta constituting the largest and with the South-Western been the intermediate. Also, freshwater resources usage can be put into two main categories, namely ex situ (withdrawal use) and in situ or in-stream use, and could also be referred to as the consumptive and non-consumptive use, respectively. With the exception of localised pollution engineered by illegal mining and other nuisance perpetuated by indigenes, the quality of water (surface and groundwater) in Ghana is generally better. The review outlined high microbial contamination of water as almost all surface waters are contaminated with either E. coli, faecal coliforms or total coliforms or all. However, these contaminations were more prevalent in surface water than groundwater.

INVESTIGATION ON BIODIVERSITY AND CONSERVATION OF FRESHWATER FISHES IN INDONESIA

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Sudarto Sudarto

2012-12-01

Full Text Available Indonesia is one of the richest regions in the world in terms of biodiversity. However, recent evidence has shown that tropical forests destruction has maintained at a high rate over the last few years in this country. At the same time, living resources in Indonesian freshwater ecosystems are important: this country ranks at number seven in terms of production of inland capture fisheries with 323,150 tonnes in 2008. Freshwater fishes represent 42% of the total estimated ichthyofauna, concentrated in 0.01% of the total water covered environment. This environment is closer to human activities, making it critically vulnerable to adverse impacts. Furthermore, there has been some recent debates on the general sustainability of fisheries and aquaculture production systems. This research was focused on initiating a multi-scale study of fish biodiversity in freshwater environments. Two specific actions have been started. A review based on the analyses of the existing scientific literature and of databases on fish taxonomy and distributions. In parallel to this work, a global analysis of the distribution of fish diversity in Indonesia was undertaken. This work aims at identifying the major features of this resource as well as its current and future threats.

Combined ecological risks of nitrogen and phosphorus in European freshwaters

International Nuclear Information System (INIS)

Azevedo, Ligia B.; Zelm, Rosalie van; Leuven, Rob S.E.W.; Hendriks, A. Jan; Huijbregts, Mark A.J.

2015-01-01

Eutrophication is a key water quality issue triggered by increasing nitrogen (N) and phosphorus (P) levels and potentially posing risks to freshwater biota. We predicted the probability that an invertebrate species within a community assemblage becomes absent due to nutrient stress as the ecological risk (ER) for European lakes and streams subjected to N and P pollution from 1985 to 2011. The ER was calculated as a function of species-specific tolerances to NO 3 − and total P concentrations and water quality monitoring data. Lake and stream ER averaged 50% in the last monitored year (i.e. 2011) and we observed a decrease by 22% and 38% in lake and stream ER (respectively) of river basins since 1985. Additionally, the ER from N stress surpassed that of P in both freshwater systems. The ER can be applied to identify river basins most subjected to eutrophication risks and the main drivers of impacts. - Highlights: • Ecological risk was estimated as response additions of N and P. • The risk posed by N stress is higher than that by P in European freshwaters. • Ecological risks have remained unchanged in most European river basins. - Quantifying the ecological risk of invertebrate losses due to N and P pollution

Body armour and lateral-plate reduction in freshwater three-spined stickleback Gasterosteus aculeatus: adaptations to a different buoyancy regime?

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Myhre, F; Klepaker, T

2009-11-01

Several factors related to buoyancy were compared between one marine and two freshwater populations of three-spined stickleback Gasterosteus aculeatus. Fish from all three populations had buoyancy near to neutral to the ambient water. This showed that neither marine nor freshwater G. aculeatus used swimming and hydrodynamic lift to prevent sinking. Comparing the swimbladder volumes showed that freshwater completely plated G. aculeatus had a significantly larger swimbladder volume than both completely plated marine and low-plated freshwater G. aculeatus. Furthermore, body tissue density was lower in low-plated G. aculeatus than in the completely plated marine and freshwater fish. The results show that G. aculeatus either reduce tissue density or increase swimbladder volume to adapt to lower water density. Mass measurements of lateral plates and pelvis showed that loss of body armour in low-plated G. aculeatus could explain the tissue density difference between low-plated and completely plated G. aculeatus. This suggests that the common occurrence of plate and armour reduction in freshwater G. aculeatus populations can be an adaptation to a lower water density.

Late Pleistocene fishes of the Tennessee River Basin: an analysis of a late Pleistocene freshwater fish fauna from Bell Cave (site ACb-2) in Colbert County, Alabama, USA.

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Jacquemin, Stephen J; Ebersole, Jun A; Dickinson, William C; Ciampaglio, Charles N

2016-01-01

The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (∼10,000 to 30,000 years B.P.) leading to modern Holocene fish diversity patterns. The objective of this study was to describe the fish assemblages of the Tennessee River Basin from the late Pleistocene using a series of faunas from locales throughout the basin documented from published literature, unpublished reports, and an undocumented fauna from Bell Cave (site ACb-2, Colbert County, AL). Herein we discuss 41 unequivocal taxa from 10 late Pleistocene localities within the basin and include a systematic discussion of 11 families, 19 genera, and 24 identifiable species (28 unequivocal taxa) specific to the Bell Cave locality. Among the described fauna are several extirpated (e.g., Northern Pike Esox lucius, Northern Madtom Noturus stigmosus) and a single extinct (Harelip Sucker Moxostoma lacerum) taxa that suggest a combination of late Pleistocene displacement events coupled with more recent changes in habitat that have resulted in modern basin diversity patterns. The Bell Cave locality represents one of the most intact Pleistocene freshwater fish deposits anywhere in North America. Significant preservational, taphonomic, sampling, and identification biases preclude the identification of additional taxa. Overall, this study provides a detailed look into paleo-river ecology, as well as freshwater fish diversity and distribution leading up to the contemporary biodiversity patterns of the Tennessee River Basin and Mississippi River Basin as a whole.

Late Pleistocene fishes of the Tennessee River Basin: an analysis of a late Pleistocene freshwater fish fauna from Bell Cave (site ACb-2 in Colbert County, Alabama, USA

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Stephen J. Jacquemin

2016-02-01

Full Text Available The Tennessee River Basin is considered one of the most important regions for freshwater biodiversity anywhere on the globe. The Tennessee River Basin currently includes populations of at least half of the described contemporary diversity of extant North American freshwater fishes, crayfish, mussel, and gastropod species. However, comparatively little is known about the biodiversity of this basin from the Pleistocene Epoch, particularly the late Pleistocene (∼10,000 to 30,000 years B.P. leading to modern Holocene fish diversity patterns. The objective of this study was to describe the fish assemblages of the Tennessee River Basin from the late Pleistocene using a series of faunas from locales throughout the basin documented from published literature, unpublished reports, and an undocumented fauna from Bell Cave (site ACb-2, Colbert County, AL. Herein we discuss 41 unequivocal taxa from 10 late Pleistocene localities within the basin and include a systematic discussion of 11 families, 19 genera, and 24 identifiable species (28 unequivocal taxa specific to the Bell Cave locality. Among the described fauna are several extirpated (e.g., Northern Pike Esox lucius, Northern Madtom Noturus stigmosus and a single extinct (Harelip Sucker Moxostoma lacerum taxa that suggest a combination of late Pleistocene displacement events coupled with more recent changes in habitat that have resulted in modern basin diversity patterns. The Bell Cave locality represents one of the most intact Pleistocene freshwater fish deposits anywhere in North America. Significant preservational, taphonomic, sampling, and identification biases preclude the identification of additional taxa. Overall, this study provides a detailed look into paleo-river ecology, as well as freshwater fish diversity and distribution leading up to the contemporary biodiversity patterns of the Tennessee River Basin and Mississippi River Basin as a whole.

Benthic macrofaunal structure and secondary production in tropical estuaries on the Eastern Marine Ecoregion of Brazil.

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Bissoli, Lorena B; Bernardino, Angelo F

2018-01-01

Tropical estuaries are highly productive and support diverse benthic assemblages within mangroves and tidal flats habitats. Determining differences and similarities of benthic assemblages within estuarine habitats and between regional ecosystems may provide scientific support for management of those ecosystems. Here we studied three tropical estuaries in the Eastern Marine Ecoregion of Brazil to assess the spatial variability of benthic assemblages from vegetated (mangroves) and unvegetated (tidal flats) habitats. A nested sampling design was used to determine spatial scales of variability in benthic macrofaunal density, biomass and secondary production. Habitat differences in benthic assemblage composition were evident, with mangrove forests being dominated by annelids (Oligochaeta and Capitellidae) whereas peracarid crustaceans were also abundant on tidal flats. Macrofaunal biomass, density and secondary production also differed between habitats and among estuaries. Those differences were related both to the composition of benthic assemblages and to random spatial variability, underscoring the importance of hierarchical sampling in estuarine ecological studies. Given variable levels of human impacts and predicted climate change effects on tropical estuarine assemblages in Eastern Brazil, our data support the use of benthic secondary production to address long-term changes and improved management of estuaries in Eastern Brazil.

Distinction between saltwater drowning and freshwater drowning by assessment of sinus fluid on post-mortem computed tomography

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Kawasumi, Yusuke; Sato, Yuki; Sato, Yumi; Ishibashi, Tadashi [Tohoku University Graduate School of Medicine, Department of Clinical Imaging, Sendai, Miyagi (Japan); Usui, Akihito; Daigaku, Nami; Hosokai, Yoshiyuki [Tohoku University Graduate School of Medicine, Department of Diagnostic Image Analysis, Sendai, Miyagi (Japan); Hayashizaki, Yoshie; Funayama, Masato [Tohoku University Graduate School of Medicine, Department of Forensic Medicine, Sendai, Miyagi (Japan)

2016-04-15

To evaluate the difference in sinus fluid volume and density between saltwater and freshwater drowning and diagnose saltwater drowning in distinction from freshwater drowning. Ninety-three drowning cases (22 saltwater and 71 freshwater) were retrospectively investigated; all had undergone post-mortem CT and forensic autopsy. Sinus fluid volume and density were calculated using a 3D-DICOM workstation, and differences were evaluated. Diagnostic performance of these indicators for saltwater drowning was evaluated using a cut-off value calculated by receiver operating characteristic (ROC) analysis. The median sinus fluid volume was 5.68 mL in cases of saltwater drowning (range 0.08 to 37.55) and 5.46 mL in cases of freshwater drowning (0.02 to 27.68), and the average densities were 47.28 (14.26 to 75.98) HU and 32.56 (-14.38 to 77.43) HU, respectively. While sinus volume did not differ significantly (p = 0.6000), sinus density was significantly higher in saltwater than freshwater drowning cases (p = 0.0002). ROC analysis for diagnosis of saltwater drowning determined the cut-off value as 37.77 HU, with a sensitivity of 77 %, specificity of 72 %, PPV of 46 % and NPV of 91 %. The average density of sinus fluid in cases of saltwater drowning was significantly higher than in freshwater drowning cases; there was no significant difference in the sinus fluid volume. (orig.)

Distinction between saltwater drowning and freshwater drowning by assessment of sinus fluid on post-mortem computed tomography

International Nuclear Information System (INIS)

Kawasumi, Yusuke; Sato, Yuki; Sato, Yumi; Ishibashi, Tadashi; Usui, Akihito; Daigaku, Nami; Hosokai, Yoshiyuki; Hayashizaki, Yoshie; Funayama, Masato

2016-01-01

To evaluate the difference in sinus fluid volume and density between saltwater and freshwater drowning and diagnose saltwater drowning in distinction from freshwater drowning. Ninety-three drowning cases (22 saltwater and 71 freshwater) were retrospectively investigated; all had undergone post-mortem CT and forensic autopsy. Sinus fluid volume and density were calculated using a 3D-DICOM workstation, and differences were evaluated. Diagnostic performance of these indicators for saltwater drowning was evaluated using a cut-off value calculated by receiver operating characteristic (ROC) analysis. The median sinus fluid volume was 5.68 mL in cases of saltwater drowning (range 0.08 to 37.55) and 5.46 mL in cases of freshwater drowning (0.02 to 27.68), and the average densities were 47.28 (14.26 to 75.98) HU and 32.56 (-14.38 to 77.43) HU, respectively. While sinus volume did not differ significantly (p = 0.6000), sinus density was significantly higher in saltwater than freshwater drowning cases (p = 0.0002). ROC analysis for diagnosis of saltwater drowning determined the cut-off value as 37.77 HU, with a sensitivity of 77 %, specificity of 72 %, PPV of 46 % and NPV of 91 %. The average density of sinus fluid in cases of saltwater drowning was significantly higher than in freshwater drowning cases; there was no significant difference in the sinus fluid volume. (orig.)

PBDEs in freshwater mussels and fish from Flanders, Belgium

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Covaci, A.; Voorspoels, S.; Schepens, P. [Antwerp Univ. (Belgium). Toxicological Center; Bervoets, L.; Hoff, P.; Voets, J.; Campenhout, K. van; Blust, R. [Antwerp Univ. (Belgium). Dept. of Ecophysiology, Biochemistry and Toxicology

2004-09-15

Polybrominated diphenylethers (PBDEs), a class of brominated flame retardants (BFRs), are widely used in textiles, plastics, electronic equipment and other materials for more than 30 years. Due to their massive use, PBDEs have become ubiquitously present in aquatic organisms and it was recently evidenced that their levels seem to increase rapidly. Higher PBDE concentrations were found in biota from freshwater compared to similar marine species. This is probably due to a higher pollution load found near point pollution sources that are almost exclusively inland located. Zebra mussels (Dreissena polymorpha) fulfil the requirements of a good biomonitoring organism for freshwater ecosystems: they are easy to collect and to handle, are available in sufficient numbers, have a relative long lifespan, are sedentary and resistant to various types of pollution without suffering a too high mortality and have a high filtration rate which favours the bioaccumulation of organic contaminants. Fish species are another suitable tool for the biomonitoring of organic contaminants. The occurrence of PBDEs in fish species from Europe has already received some attention, but the amount of data is still limited. The aim of this study was to evaluate the occurence of PBDEs in zebra mussels and several representative freshwater fish species (eel, carp and gibel carp) at different sites in Flanders, Belgium. In parallel, other organohalogenated contaminants, such as polychlorinated biphenyls (PCBs), p,p'-DDE and hexachlorobenzene (HCB) were also measured and their relationship with PBDEs was investigated.

Effect of Global Warming and Increased Freshwater Flux on Northern Hemispheric Cooling

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Girihagama, L. N.; Nof, D.

2016-02-01

We wish to answer the, fairly complicated, question of whether global warming and an increased freshwater flux can cause Northern Hemispheric warming or cooling. Starting from the assumption that the ocean is the primary source of variability in the Northern hemispheric ocean-atmosphere coupled system, we employed a simple non-linear one-dimensional coupled ocean-atmosphere model. The simplicity of the model allows us to analytically predict the evolution of many dynamical variables of interest such as, the strength of the Atlantic Meridional overturning circulation (AMOC), temperatures of the ocean and atmosphere, mass transports, salinity, and ocean-atmosphere heat fluxes. The model results show that a reduced AMOC transport due to an increased freshwater flux causes cooling in both the atmosphere and ocean in the North Atlantic (NA) deep-water formation region. Cooling in both the ocean and atmosphere can cause reduction of the ocean-atmosphere temperature difference, which in turn reduces heat fluxes in both the ocean and atmosphere. For present day climate parameters, the calculated critical freshwater flux needed to arrest AMOC is 0.08 Sv. For a constant atmospheric zonal flow, there is minimal reduction in the AMOC strength, as well as minimal warming of the ocean and atmosphere. This model provides a conceptual framework for a dynamically sound response of the ocean and atmosphere to AMOC variability as a function of increased freshwater flux. The results are qualitatively consistent with numerous realistic coupled numerical models of varying complexity.

Relative abundance of mesopredators and size of oak patches in the cross-timbers ecoregion

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Disney, M.R.; Hellgren, E.C.; Davis, C.A.; Leslie, David M.; Engle, David M.

2008-01-01

Mesopredators (e.g., raccoon Procyon lotor, Virginia opossum Didelphis virginiana, striped skunk Mephitis mephitis) have received considerable attention because of links to population declines in birds via increased nest predation, especially in landscapes fragmented by anthropogenic forces. Relationships of abundance of mesopredators to size of habitat patches have received less attention than relationships to other metrics of fragmentation, particularly edge characteristics. We tested the hypothesis that relative abundance of mesopredators (e.g., raccoons and Virginia opossums) was related negatively to size of forest patch. We delineated 15 patches of oak (Quercus) forest ranging from 0.2 to 55.3 ha within a grassland-woodland mosaic in the cross-timbers ecoregion of Oklahoma. Scent stations and live traps within these patches were used to index relative abundance of mesopredators in summers 2003 and 2004. Both indices of relative abundance were related weakly and negatively to area of forest patch. However, rate of capture and visitation to scent station were not correlated consistently throughout the study. Our results suggested that the two methods to index abundance provided separate information on functional and numerical responses to size of patch. Our evidence that mesopredators within the cross timbers were more likely to be in smaller patches of oak forest may have implications to success of avian nesting in these patches.

Management of protected areas in Sahel savannah ecoregion of Nigeria under the threat of desertification

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BOROKINI Temitope Israel

2013-12-01

Full Text Available This study was conducted to assess the challenges facing 8 selected protected areas in the Sahel Savannah ecoregion and proffer solutions to these challenges in order to ensure conservation and sustainability of Nigeria’s biodiversity. Primary data were collected from randomly-selected 120 staffs using questionnaire administration from 8 Forest Reserves within Borno and Yobe states of Nigeria. A high level of encroachment of all the studied protected areas was observed, which ranged from deforestation, overgrazing, poaching to converting protected areas into farmlands. Other notable challenges include poor staffing, inadequate equipment and funding. The respondents further reported that majority of the defaulters were farmers and local people in the area, involved in such practices for their survival in the wake of harsher climate and desert encroachment in the region. This paper calls for a revision of the Government Policy on Forestry in Nigeria to allow the people own and plant forests, implementation of community based forest resources management, provision of environment and user-friendly solar powered cooking stoves and sustainable farming systems such as crop rotation, intercropping, sustainable irrigation, organic farming and agroforestry. In addition, sources of income for the locals need to be diversified, such as honey bee production.

Research on marine and freshwater fish identification model based on hyper-spectral imaging technology

Science.gov (United States)

Fu, Yan; Guo, Pei-yuan; Xiang, Ling-zi; Bao, Man; Chen, Xing-hai

2013-08-01

With the gradually mature of hyper spectral image technology, the application of the meat nondestructive detection and recognition has become one of the current research focuses. This paper for the study of marine and freshwater fish by the pre-processing and feature extraction of the collected spectral curve data, combined with BP network structure and LVQ network structure, a predictive model of hyper spectral image data of marine and freshwater fish has been initially established and finally realized the qualitative analysis and identification of marine and freshwater fish quality. The results of this study show that hyper spectral imaging technology combined with the BP and LVQ Artificial Neural Network Model can be used for the identification of marine and freshwater fish detection. Hyper-spectral data acquisition can be carried out without any pretreatment of the samples, thus hyper-spectral imaging technique is the lossless, high- accuracy and rapid detection method for quality of fish. In this study, only 30 samples are used for the exploratory qualitative identification of research, although the ideal study results are achieved, we will further increase the sample capacity to take the analysis of quantitative identification and verify the feasibility of this theory.

Screening of freshwater fungi for decolorizing multiple synthetic dyes.

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Yang, Panpan; Shi, Wenxiao; Wang, Hongkai; Liu, Hongmei

The biodegradation of synthetic dyes by fungi is emerging as an effective and promising approach. In the present study, freshwater fungal strains isolated from submerged woods were screened for the decolorization of 7 synthetic dyes. Subsequently, 13 isolates with high decolorization capability were assessed in a liquid system; they belonged to 9 different fungal species. Several strains exhibited a highly effective decolorization of multiple types of dyes. New absorbance peaks appeared after the treatment with 3 fungal strains, which suggests that a biotransformation process occurred through fungal biodegradation. These results showed the unexploited and valuable capability of freshwater fungi for the treatment of dye-containing effluents. The ability of certain fungi to decolorize dyes is reported here for the first time. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

The effect of increasing salinity and forest mortality on soil nitrogen and phosphorus mineralization in tidal freshwater forested wetlands

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Noe, Gregory B.; Krauss, Ken W.; Lockaby, B. Graeme; Conner, William H.; Hupp, Cliff R.

2013-01-01

Tidal freshwater wetlands are sensitive to sea level rise and increased salinity, although little information is known about the impact of salinification on nutrient biogeochemistry in tidal freshwater forested wetlands. We quantified soil nitrogen (N) and phosphorus (P) mineralization using seasonal in situ incubations of modified resin cores along spatial gradients of chronic salinification (from continuously freshwater tidal forest to salt impacted tidal forest to oligohaline marsh) and in hummocks and hollows of the continuously freshwater tidal forest along the blackwater Waccamaw River and alluvial Savannah River. Salinification increased rates of net N and P mineralization fluxes and turnover in tidal freshwater forested wetland soils, most likely through tree stress and senescence (for N) and conversion to oligohaline marsh (for P). Stimulation of N and P mineralization by chronic salinification was apparently unrelated to inputs of sulfate (for N and P) or direct effects of increased soil conductivity (for N). In addition, the tidal wetland soils of the alluvial river mineralized more P relative to N than the blackwater river. Finally, hummocks had much greater nitrification fluxes than hollows at the continuously freshwater tidal forested wetland sites. These findings add to knowledge of the responses of tidal freshwater ecosystems to sea level rise and salinification that is necessary to predict the consequences of state changes in coastal ecosystem structure and function due to global change, including potential impacts on estuarine eutrophication.

Freshwater algae competition and correlation between their growth and microcystin production.

Science.gov (United States)

Álvarez, Xana; Valero, Enrique; Cancela, Ángeles; Sánchez, Ángel

2016-11-01

There are some different freshwater algae in Eutrophic reservoirs which bloom with specific environmental conditions, and some of them are cyanobacteria. In this investigation, we have cultivated microalgae present in natural water samples from a eutrophic reservoir. Variations in temperature and light were evaluated, as well as the competition among different green algae and cyanobacteria. There were three different freshwater algae growing together, Scenedesmus sp., Kirchneriella sp. and Microcystis aeruginosa, this cyanobacterium was the algae that reached the highest development and growth during the culture. While the algae grew, the concentration of toxin (microcystin-LR) increased until it reached the highest levels at 570 μg g -1 . Blooms occurred at temperatures of 28 ± 1.5 °C and light cycles of longer hours of light than dark. This took place during the summer months, from June to September (in the study area). At temperatures below 18 °C, algae did not grow. Blooms were reproduced to a laboratory scale in different conditions in order to understand the development of freshwater algae, as well as to help decision-making about water supply from that reservoir.