2002 Progress Report: Macrobenthic Process Indicators of Estuarine Condition for the Northern Gulf of Mexico

EPA Grant Number: R829458C008
Subproject: this is subproject number 008 , established and managed by the Center Director under grant R829458
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: EAGLES - Consortium for Estuarine Ecoindicator Research for the Gulf of Mexico
Center Director: Brouwer, Marius
Title: Macrobenthic Process Indicators of Estuarine Condition for the Northern Gulf of Mexico
Investigators: Rakocinski, Chet
Institution: University of Mississippi Main Campus
EPA Project Officer: Hiscock, Michael
Project Period: December 1, 2001 through November 30, 2005 (Extended to May 20, 2007)
Project Period Covered by this Report: December 1, 2001 through November 30, 2002
RFA: Environmental Indicators in the Estuarine Environment Research Program (2000) RFA Text |  Recipients Lists
Research Category: Water , Ecosystems , Ecological Indicators/Assessment/Restoration

Objective:

The main objectives of this research project are to: (1) develop automated procedures for characterizing macrobenthic-process responses; (2) field validate macrobenthic process responses in our pilot study; and (3) hold biannual meetings with Consortium for Estuarine Ecoindicator Research (CEER) researchers and Coastal 2000 managers.

Progress Summary:

Project activities began in May 2002. From May through June 2002, equipment and materials were obtained including a Nikon Image Analysis System for making laboratory measurements of the organisms' volumes.

Laboratory Standard Operating Procedures (SOPs) Development. SOPs were developed for completing three progressive stages of laboratory processing of sorted macrobenthic samples: (1) size fractionation, (2) taxonomic identification, and (3) volumetric determinations. Macrofaunal organisms are subdivided into nine possible size fractions using nested standard sieves and then transferred to taxonomic experts for identification, usually to species. This level of detail will allow for the calculation of the conventional, as well as new, macrobenthic indicators. In the third phase, volumetric determinations are made of the taxonomic size-fractions using image analysis.

Calibrations of Image Analysis System. The image analysis system was calibrated so that volumes could be accurately estimated from known areas of squashed material. Several sets of squash plates were constructed using microscope slides and cover slips for use at finer or coarser scales of volumetric resolution. Squash plates were calibrated using the Metavue imaging software, and from this data, standard area-volume curves were generated for each set of squash plates. The calibrated squash-plate technique is used to measure volumes of benthic organisms, which have been size sorted and identified.

During late spring 2002, we obtained two YSI DataSondes and supplies, developed draft SOPs, and developed plans for two macrobenthic demonstration projects.

Grand Bay National Estuarine Research Reserve System (NERR) Macrobenthic Demonstration Project. The Grand Bay NERR Macrobenthic Demonstration Project was envisaged as a pilot study to develop macrobenthic methods to assess the feasibility of using the macrobenthic size spectrum and other measures of macrobenthic processes as ecoindicators. This demonstration project was conducted in the Grand Bay NERR from July 18-20, 2002, during peak summer temperatures. Two transects were established within each of two parallel bayou systems, Bayou Heron (BH) and Bayou Cumbest (BC), starting in the upper portions of the bayous and proceeding downstream into the adjoining bay systems. Five stations were located along each transect, and stations were placed at geometrically increasing distances (i.e., 0.5, 1.0, 2.0, and 4 km). BH is in a pristine reserve area with naturally low dissolved oxygen (DO) at some stations, whereas BC is in an area thought to be moderately affected by residential wastewater runoff with exacerbated low DO in some areas.

East Bay (Pensacola) – Seasonal Comparison. The East Pensacola Bay study was envisaged as a spatio-temporal comparison of low DO effects as reflected by macrobenthic process ecoindicators. To document possible macrofaunal recovery processes as reflected by macrobenthic indicators, the temporal frame of reference for the East Pensacola Bay study encompassed two sample periods, the first in September immediately following the low DO period, and another in November, after dissipation of the DO period. Between September 8 and 10, 2002, benthic sampling was conducted at five stations at geometrically increasing distances (doubling starting on a 0.5-km scale) across a transect in East Pensacola Bay. The transect encompassed five stations running between U.S. Environmental Protection Agency (EPA) Gulf Ecology Division (GED) station P12, where very low DO was measured this summer, and the southern end of Garcon Point. This transect focused on a low DO area of concern, thereby complementing GED objectives with regard to the development of a box model of eutrophication for the area, while simultaneously, the transect encompassed the area around the south tip of Garcon Point, where the CEER-Gulf of Mexico (GOM) Crustacea Hypoxia group also worked. John Macauley of EPA GED assisted the CEER-GOM benthic sampling effort in the East Bay and GED provided a Monarch boat equipped with a hydraulic winch for benthic sampling. Sampling protocols followed those used for the Grand Bay pilot study. Sediment characteristics changed from a muddy ooze to sandy mud, and then to muddy sand across the transect. A complementary transition in the apparent body-size distributions of the macroinfauna also was noted during sampling.

A followup field trip was made to sample the five stations in East Pensacola Bay during November 13-15, 2002. The followup CEER-GOM benthic sampling effort was assisted by Mr. Craven and Ms. Smith of the EPA GED. GED again provided a Monarch boat equipped with a hydraulic winch for benthic sampling. In addition to the above noted sampling procedures, an additional macrobenthic grab was taken at each station in November 2002 to provide organisms for the examination of possible biochemical indicators. For each station, selected organisms were preserved in RNA later solution in the field. Remaining sample material containing live organisms from the extra grabs was transported back to the laboratory on ice for later removal of organisms. These organisms were frozen at -71°C for possible later lipid analysis.

Laboratory Analyses

Sample Sorting. Macrofaunal organisms now have been removed from all 60 grab samples from the Grand Bay NERR and East Pensacola Bay.

Laboratory SOP Development. SOPs were developed for completing three progressive stages of laboratory processing of sorted macrobenthic samples: (1) size fractionation, (2) taxonomic identification, and (3) volumetric determinations. Macrofaunal organisms were subdivided into nine possible size fractions using nested standard sieves and were transferred to taxonomic experts for identification, usually to species. This level of detail will allow for the calculation of the conventional as well as new macrobenthic indicators. In the third phase, volumetric determinations are made of the taxonomic size-fractions using image analysis.

Macrobenthic Sample Processing. All 60 macrobenthic samples from the Grand Bay NERR and East Pensacola Bay pilot studies have been size fractionated and organisms from 27 of 30 Grand Bay samples have been taxonomically identified. The taxonomic-size fractions from 6 of the 10 NERR stations are completed and the rest of the NERR samples currently are being volumetrically determined.

Sediment Composition Determination. The custody of all sediment composition samples from the Grand Bay NERR and East Pensacola Bay studies was transferred to University of Southern Mississippi (USM) Gulf Coast Research Laboratory (GCRL) Marine Geology Laboratory. The processing of sediment samples for sediment composition and grain size parameters has been completed for all sediment samples from both the NERR and East Pensacola Bay studies.

Sediment Total Organic Carbon (TOC) Determination. The custody of all sediment TOC samples from the Grand Bay NERR and East Pensacola Bay studies was transferred to USM GCRL Environmental Chemistry Laboratory. Sediment TOC determinations now have been completed for all samples from the Grand Bay NERR and East Pensacola Bay studies.

Pore Water Determination. Fifteen of the 20 pore water samples were transferred to the University of West Florida analytical laboratory, where sediment nutrient content analysis is proceeding. Pore water has been extracted from the remaining five pore water samples and the samples are frozen at -70°C, while awaiting transfer to the University of West Florida for processing.

Preliminary Results. Processing time for benthic samples has been slowed down by the time required for the development of SOPs. Also, the level of detail required to allow for comparisons of new and formerly used benthic indicators has been cumbersome. For example, after size fractionation and taxonomic identification are completed, broken-down samples may consist of as many of 80 vials for the volumetric determination stage. Nevertheless, our methodology appears to be working well and we expect the time requirements for processing samples to become more streamlined. In addition, we will soon be hiring an additional experienced Masters-level technician.

To date, we have made considerable progress toward obtaining macrobenthic indicator data for the 2002 samples. Our objective is to obtain all of the processed benthic samples before the next sampling season begins in May 2003. Again, all 2002 benthic samples have been sorted and all organisms have been identified from the first pilot study conducted at the Grand Bay NERR, encompassing 10 stations. We now are making volumetric determinations and these have been completed for 6 of the 10 NERR stations. Benthic sample data analysis also is progressing well. Procedures currently are being applied for estimating secondary production and for generating biomass spectra with the data.

Macrofaunal indicators that will be examined in relation to organic and nutrient loading and consequent DO stress based on our procedures include: (1) biomass size spectra; (2) secondary production estimates; (3) trophic production dynamics; (4) comparisons of items 1 through 3 with the Environmental Monitoring and Assessment Program-E Benthic Index; and (5) relationships between items 1 through 3 and sediment properties as well as biochemical indicators. Two stations, including one from each of the two NERR Bayou systems, recently have been analyzed for the 2002 EPA Estuarine and Great Lakes (EaGLe) Program Annual Meeting: Station 2 was located in the upper portion of BH and Station 7 was located in the upper portion of BC, which receives moderate residential runoff. The total macrofaunal volume was almost twice as high at the BC station, with considerably higher biomass amounts in the 1.0, 1.4, and 2.0 sieve mesh-size fractions. Accordingly, these biomass differences translated into estimated daily production values of 5,846 µg d-1 m-2 at the upper BH station and 9,856 µg d-1 m-2 at the upper BC station. The annual productivity:biomass ratio based on that daily rate of production was 14.6 at the former station versus 9.2 at the latter station, implying a somewhat slower rate of faunal turnover at the BC station.

During the course of the first year of the CEER-GOM project, representatives of the benthic-ecoindicator team have attended various meetings involving other CEER researchers, with EPA personnel, and with state managers. An all-hands meeting of the CEER-GOM components was held in Spring 2002 to initiate the project and solidify the objectives of Year 1. Various meetings were attended at the EPA GED laboratory including two collaboration meetings in spring 2002. Also, two collaborative meetings were attended on May 31, 2002, to discuss the integration with the biofilm component, and on June 11, 2002, to visit the laboratory of Dr. Devereaux of GED to observe sediment biogeochemistry methods including pore water extraction and micromanipulator sediment oxygen. On June 26, 2002, macrobenthic personnel attended the Near Coastal Assessment (NCA) field demonstration for the 2002 index period to develop parallel macrobenthic field SOPs with the NCA protocols. Subsequently, field SOPs were developed for sampling macrofauna and sediment characteristics and standard forms and labeling protocols were devised for field sampling, chain-of-custody, and sample processing.

The CEER-GOM macrobenthic component, together with Crustacean Hypoxia component, currently is represented on the Nutrient Task Force Coastal and Estuaries Subcommittee for the Mississippi Department of Environmental Quality. This committee is charged with determining nutrient criteria for the State of Mississippi coastal waters. There have been some enthusiastic discussions of the possiblity of the transfer of macrobenthic and other CEER-GOM indicators for trial use for an anticipated state nutrient criteria monitoring program. The CEER-GOM macrobenthic component also was represented at the December 2002 all-EaGLe meeting in Annapolis, MD.

Future Activities:

In the future, we plan to expand and integrate our approach with other CEER-GOM components and across EaGLe Centers through: (1) a 3-year comparative study within the three northern GOM estuaries; (2) coordination of the benthic indicator component within CEER-GOM; (3) cross-center collaborations; (4) comparison of relationships among new benthic indicators and the EPA benthic index; (5) integration of benthic indicator data with other project components into a broader synthesis; and (6) transfer of methodology to state monitoring programs.

Journal Articles:

No journal articles submitted with this report: View all 13 publications for this subproject

Supplemental Keywords:

population, Nikon Image Analysis System, dissolved oxygen, DO, community, ecosystem, watersheds, estuary, Gulf of Mexico, nutrients, hypoxia, innovative technology, ecoindicators, biomarkers, water quality, remote sensing, geographic information systems, GIS, integrated assessment, risk assessment, fisheries, conservation, restoration., RFA, Scientific Discipline, Geographic Area, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Ecosystem/Assessment/Indicators, Aquatic Ecosystem, Aquatic Ecosystems, Environmental Monitoring, Ecological Monitoring, Ecological Risk Assessment, Ecology and Ecosystems, Biology, Gulf of Mexico, Ecological Indicators, monitoring, ecoindicator, ecological exposure, estuaries, estuarine integrity, ecosystem monitoring, CEER-GOM, estuarine ecoindicator, benthic indicators, environmental indicators, environmental stress, water quality

Progress and Final Reports:

Original Abstract
  • 2003 Progress Report
  • 2004 Progress Report
  • 2005 Progress Report
  • 2006
  • Final

  • Main Center Abstract and Reports:

    R829458    EAGLES - Consortium for Estuarine Ecoindicator Research for the Gulf of Mexico

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R829458C001 Remote Sensing of Water Quality
    R829458C002 Microbial Biofilms as Indicators of Estuarine Ecosystem Condition
    R829458C003 Individual Level Indicators: Molecular Indicators of Dissolved Oxygen Stress in Crustaceans
    R829458C004 Data Management and Analysis
    R829458C005 Individual Level Indicators: Reproductive Function in Estuarine Fishes
    R829458C006 Collaborative Efforts Between CEER-GOM and U.S. Environmental Protection Agency (EPA)-Gulf Ecology Division (GED)
    R829458C007 GIS and Terrestrial Remote Sensing
    R829458C008 Macrobenthic Process Indicators of Estuarine Condition for the Northern Gulf of Mexico
    R829458C009 Modeling and Integration