United States Office of Water EPA-822-R-08-022 Environmental Protection Office of Science and Technology December 2008 Agency Washington, DC 20460 www.epa.gov METHODS FOR EVALUATING WETLAND CONDITION #18 Biogeochemical Indicators United States Office of Water EPA-822-R-08-022 Environmental Protection Office of Science and Technology December 2008 Agency Washington, DC 20460 www.epa.gov METHODS FOR EVALUATING WETLAND CONDITION #18 Biogeochemical Indicators Major Contributors University of Florida, Institute of Food and Agriculture, Soil and Water Science Department K. Ramesh Reddy and Mark W. Clark Prepared jointly by: The U.S. Environmental Protection Agency Health and Ecological Criteria Division (Office of Science and Technology) and Wetlands Division (Office of Wetlands, Oceans, and Watersheds) Notice The material in this document has been subjected to U.S. Environmental Protection Agency (EPA) technical review and has been approved for publication as an EPA document. The information contained herein is offered to the reader as a review of the “state of the science” concerning wetland bioassessment and nutrient enrichment and is not intended to be prescriptive guidance or firm advice. Mention of trade names, products or services does not convey, and should not be interpreted as conveying official EPA approval, endorsement, or recommendation. Appropriate Citation U.S. EPA. 2008. Methods for Evaluating Wetland Condition: Biogeochemical Indicators. Office of Water, U.S. Environmental Protection Agency, Washington, DC. EPA-822-R-08-022. Acknowledgements EPA acknowledges the contributions of K. Ramesh Reddy and Mark W. Clark, both of University of Florida for writing this module. This entire document can be downloaded from the following U.S. EPA websites: http://www.epa.gov/waterscience/criteria/wetlands/ http://www.epa.gov/owow/wetlands/bawwg/publicat.html iii CONTENTS FORE W ORD . V. I LIST OF “METHODS FOR EVALUATING WETLAND CONDITION ” MODULES . VI. I SU mm ARY . 1. PUR P OSE . 1. INTRODU C TION . 1. CHARA C TERISTI C S OF THE SOIL AND WATER COLU M N . 4. BASI C ELE M ENTAL CY C LES . 5. REFEREN C E WETLANDS . 1. 1 SA mp LING PROTO C OL . 1. 2 WATER SA mp LING . 1. 5 SOIL SA mp LING . 1. 5 BIOGEO C HE M I C AL INDI C ATORS . 1. 7 WATER QUALITY INDI C ATORS . 1. 8 SOIL QUALITY INDI C ATORS . 2. 3 MINIMUM MONITORING RE Q UIRE M ENTS . 3. 2 CASE STUDY : THE EVERGLADES . 3. 3 REFEREN C ES . 39. LIST OF FIGURES FIGURE 1: SC HE M ATI C SHO W ING THE LINKAGE B ET W EEN B IOGEO C HE M I C AL P RO C ESSES AND INDI C ATORS . .2 FIGURE 2: SC HE M ATI C SHO W ING B ASI C NUTRIENT C Y C LES IN SOIL -W ATER C OLU M N OF A W ETLAND . .4 FIGURE 3: SC HE M ATI C SHO W ING B ASI C C AR B ON C Y C LES IN THE SOIL -W ATER C OLU M N OF A W ETLAND . .6 iv FIGURE 4: SC HE M ATI C SHO W ING B ASI C NITROGEN C Y C LES IN THE SOIL -W ATER C OLU M N OF A W ETLAND . .7 FIGURE 5: SC HE M ATI C SHO W ING B ASI C P HOS P HOROUS C Y C LES IN THE SOIL -W ATER C OLU M N OF A W ETLAND . 8 FIGURE 6: SC HE M ATI C SHO W ING B ASI C SULFUR C Y C LES IN THE SOIL -W ATER C OLU M N OF A W ETLAND . 1. 0 FIGURE 7: SC HE M ATI C SHO W ING THE P RO P OSED STE P S TO DEVELO P AND EVALUATE B IOGEO C HE M I C AL INDI C ATOR C RITERIA . .1 . 2 FIGURE 8 :. AN EXA mp LE OF THE SA mp LING S C HE M E USED TO P ARTIALLY Q UANTIFY W ITHIN W ETLAND B IOGEO C HE M I C AL GRADIENTS W HILE MINIMIZING W ITHIN ZONE VARIA B ILITY AND NU mb ER OF SA mp LES FOR ANALYSIS . 1. 3 LIST OF TA B LES TA B LE 1: POTENTIAL W ATER AND SOIL Q UALITY INDI C ATORS FOR ASSESSING NUTRIENT I mp A C TS IN W ETLANDS . (*DENOTES MINIMUM DATA RE Q UIRED FOR EA C H SITE ) . .16 TA B LE 2A: BA C KGROUND C ON C ENTRATIONS (STANDARD ERROR ) SELE C TED B IOGEO C HE M I C AL INDI C ATORS IN FLO C /DETRITAL C O mp ONENT OF VARIOUS HYDROLOGI C UNITS OF THE EVERGLADES . THE PMN AND PMP REFER TO P OTENTIALLY M INERALIZA B LE N AND P, RES P E C TIVELY (WRIGHT , ET AL . 2002) . 3. 4 TA B LE 2B: BA C KGROUND C ON C ENTRATIONS (STANDARD ERROR ) SELE C TED B IOGEO C HE M I C AL INDI C ATORS IN SURFA C E SOIL (0–3 cm ) C O mp ONENT OF VARIOUS HYDROLOGI C UNITS OF THE EVERGLADES . THE PMN AND PMP REFER TO P OTENTIALLY M INERALIZA B LE N AND P, RES P E C TIVELY . (WRIGHT , ET AL . 2002) . 3. 5 TA B LE 3: Imp A C T INDI C ES AND RELATIVE SENSITIVITY OF VARIOUS B IOGEO C HE M I C AL P RO C ESSES /INDI C ATORS M EASURED IN DETRITAL AND SOIL LAYERS AT I mp A C TED AND REFEREN C E SITES IN THE EVERGLADES . D = DETRITAL LAYER AND S = 0–10 cm SOIL (REDDY , ET AL . 1999) . 3. 7 v FORE W ORD In 1999, the U.S. Environmental Protection Agency (EPA) began work on this series of reports entitled Methods for Evaluating Wetland Condition. The purpose of these reports is to help States and Tribes develop methods to evaluate (1) the overall ecological condition of wetlands using biological assessments and (2) nutrient enrichment of wetlands, which is one of the primary stressors damaging wetlands in many parts of the country. This information is intended to serve as a starting point for States and Tribes to eventually establish biological and nutrient water quality criteria specifically refined for wetland waterbodies. This purpose was to be accomplished by providing a series of “state of the science” modules concerning wetland bioassessment as well as the nutrient enrichment of wetlands. The individual module format was used instead of one large publication to facilitate the addition of other reports as wetland science progresses and wetlands are further incorporated into water quality programs. Also, this modular approach allows EPA to revise reports without having to reprint them all. A list of the inaugural set of 20 modules can be found at the end of this section. This last set of reports is the product of a collaborative effort between EPA’s Health and Ecological Criteria Division of the Office of Science and Technology (OST) and the Wetlands Division of the Office of Wetlands, Oceans and Watersheds (OWOW). The reports were initiated with the support and oversight of Thomas J. Danielson then of OWOW, Amanda K. Parker and Susan K. Jackson (OST), and seen to completion by Ifeyinwa F. Davis (OST). EPA relied on the input and expertise of the contributing authors to publish the remaining modules. More information about biological and nutrient criteria is available at the following EPA website: http://www.epa.gov/ost/standards More information about wetland biological assessments is available at the following EPA website: http://www.epa.gov/owow/wetlands/bawwg vi LIST Of “METHODS FOR EValUATING WETlanD CONDITION” MODULES MODULE # MODULE TITLE 1 . INTRODU C TION TO WETLAND BIOLOGIC AL ASSESS M ENT 2 . INTRODU C TION TO WETLAND NUTRIENT ASSESS M ENT 3 . THE STATE OF WETLAND SC IEN C E 4 . STUDY DESIGN FOR MONITORING WETLANDS 5 . AD M INISTRATIVE FRA M E W ORK FOR THE Imp LE M ENTATION OF A WETLAND BIOASSESS M ENT PROGRA M 6 . DEVELO P ING METRI C S AND INDEXES OF BIOLOGIC AL INTEGRITY 7 . WETLANDS CLASSIFIC AT ION 8 . VOLUNTEERS AND WETLAND BIO M ONITORING 9 . DEVELO P ING AN INVERTE B RATE INDEX OF BIOLOGIC AL INTEGRITY FOR WETLANDS 10 . USING VEGETATION TO ASSESS ENVIRON M ENTAL CONDITIONS IN WETLANDS 11 . USING ALGAE TO ASSESS ENVIRON M ENTAL CONDITIONS IN WETLANDS 12 . USING A mp HI B IANS IN BIOASSESS M ENTS OF WETLANDS 13 . BIOLOGIC AL ASSESS M ENT METHODS FOR BIRDS 14 . WETLAND BIOASSESS M ENT CASE STUDIES 15 . BIOASSESS M ENT METHODS FOR FISH 16 . VEGETATION -BASED INDI C ATORS OF WETLAND NUTRIENT ENRI C H M ENT 17 . LAND -USE CHARA C TERIZATION FOR NUTRIENT AND SEDI M ENT RISK ASSESS M ENT 18 . BIOGEO C HE M I C AL INDI C ATORS 19 . NUTRIENT LOADING 20 . WETLAND HYDROLOGY vii SU mm ARY PUR P OSE his module discusses biogeochemical he purpose of this module is to describe T parameters and their use as indices to T biogeochemical indicators that can be characterize the nutrient status of wetlands. used to monitor nutrients in wetland systems Biogeochemical processes in the soil and wa- in an ecologically meaningful and scientifi- ter column drive key ecosystem functions cally rigorous manner. associated with wetland values (e.g. water quality improvement through denitrification, long-term nutrient storage in the organic mat- INTRODU C TION ter, etc.). Process level measurements reflect the functionality of a wetland and potential any species depend upon wetlands for impairment due to impacts; however, these M successful completion of their life cy- measurements are often tedious and costly.