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Mercury Transfer through an Everglades Aquatic Food Web

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Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator:
William Loftus (retired)

Joel Trexler (Florida International University); Ronald Jones

Publication_Date: 2002
Title: Mercury Transfer through an Everglades Aquatic Food Web
Geospatial_Data_Presentation_Form: poster
Online_Linkage:
<https://sofia.usgs.gov/projects/index.php?project_url=merc_foodweb>
Description:
Abstract:
The general objectives of this project were to:

1. Examine trophic relationships in the Everglades fish community to identify patterns of resource use by a temperate fauna in a subtropical, seasonal wetland. 2. Group species into trophic groups based on volumetric contributions of prey items and corroborate with stable-isotope analysis. 3. Measure total Hg in water, soils, plants, invertebrates, and fishes. 4. Correlate Hg levels with trophic positions of invertebrates and fishes based on gut and stable-isotope analyses.

Purpose:
Mercury (Hg) is a neurotoxin to which the developing central nervous system of animals is particularly vulnerable. US Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) mercury (Hg) limits are exceeded by many Everglades fishes.

This study was proposed to answer a series of questions posed by a multi-agency task force convened to address the mercury problem in the Everglades. These questions included understanding the extent of contamination in aquatic biota, the pathways by which Hg moves through the aquatic food web, and the processes that affect bioaccumulation.

Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 1977
Ending_Date: 1997
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -80.875
East_Bounding_Coordinate: -80.375
North_Bounding_Coordinate: 25.75
South_Bounding_Coordinate: 25.25
Keywords:
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: mercury
Theme_Keyword: mercury contamination
Theme_Keyword: foodweb
Theme_Keyword: biology
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: biota
Theme_Keyword: environment
Theme_Keyword: inlandWaters
Theme_Keyword: 002
Theme_Keyword: 007
Theme_Keyword: 012
Place:
Place_Keyword_Thesaurus:
Department of Commerce, 1995, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions, Federal Information Processing Standard (FIPS) 10-4, Washington, DC, National Institute of Standards and Technology
Place_Keyword: United States
Place_Keyword: US
Place:
Place_Keyword_Thesaurus:
U.S. Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard 5-2): Washington, DC, NIST
Place_Keyword: Florida
Place_Keyword: FL
Place:
Place_Keyword_Thesaurus:
Department of Commerce, 1990, Counties and Equivalent Entities of the United States, Its Possessions, and Associated Areas, FIPS 6-3, Washington, DC, National Institute of Standards and Technology
Place_Keyword: Miami-Dade County
Place:
Place_Keyword_Thesaurus: USGS Geographic Names Information System
Place_Keyword: Everglades National Park
Place_Keyword: Shark River Slough
Place_Keyword: Taylor Slough
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: Central Everglades
Access_Constraints: none
Use_Constraints: none
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Joel Trexler
Contact_Organization:
Florida International University, Department of Biological Sciences
Contact_Address:
Address_Type: mailing address
Address: 11208 S.W. 8th Street
City: Miami
State_or_Province: FL
Postal_Code: 33199
Country: USA
Contact_Voice_Telephone: 305 348-1966
Contact_Facsimile_Telephone: 305 348-4032
Contact_Electronic_Mail_Address: trexlerj@fiu.edu
Data_Set_Credit:
Support provided by: Florida Dept. of Environmental Protection, Dr. Tom Atkeson; Florida International University; U. S. National Park Service; USGS-Biological Resources Division
Cross_Reference:
Citation_Information:
Originator:
Loftus, W. F.

Trexler, J. C.

Publication_Date: 2002
Title: Accumulation and Fate of Mercury in an Everglades Food Web
Geospatial_Data_Presentation_Form: poster
Publication_Information:
Publication_Place: Homestead, FL
Publisher:
U.S. Geological Survey, biological Resources Disicipline, Everglades NP Field Station
Other_Citation_Details: accessed as of 5/24/2010
Online_Linkage:
<https://sofia.usgs.gov/projects/index.php?project_url=merc_foodweb>
Cross_Reference:
Citation_Information:
Originator:
Arrington, D. A.

Winemiller, K. O.; Loftus, W. F.; Akin, S.

Publication_Date: 2002
Title: How often do fishes "run on empty">
Geospatial_Data_Presentation_Form: report
Series_Information:
Series_Name: Ecology
Issue_Identification: v. 83, n. 8, p. 2145-2151
Publication_Information:
Publication_Place: Ithica, NY
Publisher: Ecological Society of America
Other_Citation_Details:
accessed as of 11/3/2010

The full article is available via journal subscription or single article purchase. The abstract may be viewed on the website below by selecting (abstract)..

Online_Linkage:
<http://www.esajournals.org/action/doSearch?all=arrington&x=3&y=7>

Data_Quality_Information:
Logical_Consistency_Report: Only high-water samples were used in Hg correlations.
Completeness_Report:
The small size of food items required the pooling of like taxa from each size-class of fish for volumetric analysis. Invertebrate samples were composited, while large fish were homogenized and subsampled
Lineage:
Process_Step:
Process_Description:
Sample collection and processing included:

1. Fishes collected from three habitats at high and low water in a long-hydroperiod wetland at Site 1-L in Shark Slough, Everglades National Park. Only high-water samples used in Hg correlations. 2. Approximately 4,000 specimens of 26 native fishes from 1977-1981, supplemented by 6 introduced species during 1995-1997, collected with rotenone, electrofishing, nets, and angling. 3. Small size of food items required the pooling of like taxa from each size-class of fish for volumetric analysis.Volumes measured to 0.001ml with a blood-sedimentation tube. 4. For HgTotal all samples collected with clean techniques. 5. Invertebrate samples were composited, while large fish were homogenized and subsampled. 6. Whole-body samples of animals were digested with acid in sealed ampules in an autoclave. 7. Total Hg measured with atomic-fluorescence spectrometer, after generating callibration curves and including Standard Reference Materials as checks for each run.

Trophic Classification 1. Fish trophic scores were calculated by summing the products of the dietary contributions of the 34 prey types and their trophic levels 2. Scores were used to group fishes into five discrete trophic classes (guilds): 1 = Mainly Herbivorous, >50% plant material; 2 = Omnivorous, 25-50% plant material; 3 = Omnivorous, <25% Plant material; 4 = Omnivorous, mainly animal prey; 5 = Predominantly carnivorous, fish and decapods

The trophic scores and total mercury levels of the fishes were positively correlated (Spearmanís r = 0.706, P< 0.001, n=39), as were those of the invertebrates (Pearsonís r = 0.749, p < 0.001). There were significant differences in square-root-transformed total Hg concentrations among the species of fishes (ANOVA, F31,515 = 52.035, P < 0.001). The five classes differed significantly in mean Hg levels (ANOVA, F, 4, 24 = 9.17, P < 0.0005)

Nitrogen and carbon stable-isotope signatures were measured for aquatic animals and plants at Site 1-L

The second part of the project was based on the following rationale:

1. Differences in fish and invertebrate densities between short- and long-hydroperiod marshes may result from food-web differences. 2. Differing food resources may result in differences in mercury accumulation. 3. If Gambusia experience different levels of Hg, chronic exposure may result in tolerant genotypes. Transplanting of fish across hydroperiods may show differences in survival or growth.

The objectives were to:

Measure total Hg levels in wild Gambusia from 3 pairs of short- and long- hydroperiod marshes across seasons ). Estimate Hg concentrations, Hg uptake, growth rates, and survival of caged Gambusia from those marshes to compare to wild-fish patterns. Examine diet differences among hydroperiods from gut and stable-isotope analyses with relation to Hg patterns.

The methods for collecting data were:

1. Each month, a minimum of 30 specimens of wild fish were collected from each site for total Hg analysis. 2. As a control, long- and short-hydroperiod stock mosquitofish were captive-raised at ENP to be stocked into field cages. 3. Possible Hg-tolerance differences in the populations were examined by transplanting mosquitofish originating from short-hydroperiod stocks into cages at long-hydroperiod locations, and visa versa. Five cages at each site were stocked with progeny from the same hydroperiod type, and 5 alternate cages stocked with progeny from the other category

At the trialís end, stocked caged fish were recovered and wild fish were collected from the same site. All were measured and weighed (for growth analysis) and analyzed for Hg

Process_Date: 1998
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Joel Trexler
Contact_Organization:
Florida International University, Department of Biological Sciences
Contact_Address:
Address_Type: mailing address
Address: 11208 S.W. 8th Street
City: Miami
State_or_Province: FL
Postal_Code: 33199
Country: USA
Contact_Voice_Telephone: 305 348-1966
Contact_Facsimile_Telephone: 305 348-4032
Contact_Electronic_Mail_Address: trexlerj@fiu.edu

Metadata_Reference_Information:
Metadata_Date: 20101103
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Heather Henkel
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing and physical address
Address: 600 Fourth Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727 803-8747 ext 3028
Contact_Facsimile_Telephone: 727 803-2030
Contact_Electronic_Mail_Address: sofia-metadata@usgs.gov
Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Access_Constraints: none
Metadata_Use_Constraints:
The principal investigator for this project retired and the Point of Contact has declined to provide a review of the information in the metadata record. Any questions about the information should be directed to the Point of Contact under Citation Information or the Process Contact(s).

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