# Technical Support Document for

U.S. EPA’s Proposed Rule for Numeric
Nutrient Criteria for Florida ’ s Estuaries

, Coastal Waters, and South Florida Inland Flowing Waters

Introduction

November 30 , 2012Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

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### Contributing Authors

Jim Carleton, U.S. Environmental Protection Agency Tiffany Crawford, U.S. Environmental Protection Agency Ed Decker, U.S. Environmental Protection Agency Edward Dettmann, U.S. Environmental Protection Agency Erica Fleisig, U.S. Environmental Protection Agency Richard Greene, U.S. Environmental Protection Agency James Hagy, U.S. Environmental Protection Agency Galen Kaufman, U.S. Environmental Protection Agency Jacques Oliver, U.S. Environmental Protection Agency Stephanie Santell, U.S. Environmental Protection Agency Blake Schaeffer, U.S. Environmental Protection Agency Dan Scheidt, U.S. Environmental Protection Agency Mario Sengco, U.S. Environmental Protection Agency Dana Thomas, U.S. Environmental Protection Agency Brannon Walsh, U.S. Environmental Protection Agency Stephen Whitlock, U.S. Environmental Protection Agency Timothy Wool, U.S. Environmental Protection Agency Lester Yuan, U.S. Environmental Protection Agency Steven Davie, Tetra Tech, Inc. Jeroen Gerritsen, Tetra Tech, Inc. Jon Harcum, Tetra Tech, Inc. John Hochheimer, Tetra Tech, Inc. Michael Paul, Tetra Tech, Inc. Brian Watson, Tetra Tech, Inc.Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

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### Acknowledgements

The U.S. Environmental Protection Agency (EPA) acknowledges the Florida Department of Environmental Protection’s (FDEP’s) Division of Environmental Assessment and Restoration, associated state water quality programs, advisory committees, and contractors, for their collaboration in assisting the Agency’s efforts in developing numeric nutr ient criteria for Florida’s estuaries and south Florida inland flowing waters. EPA specifically thanks the following people who provided material and scientific advisory support of the Agency’s rulemaking efforts:

Mark Alderson, Sarasota Bay Estuary Program Albrey Arrington, Loxahatchee River Keeper Lisa Beaver, Charlotte Harbor National Estuary Program Joseph Boyer, National Park Service Henry Briceño, Florida International University Dean Campbell, St. Johns River Water Management District Kevin Carter, South Florida Water Management District Joffre Castro, National Park Service Holly Greening, Tampa Bay Estuary Program John Hendrickson, St. Johns River Water Management District Tony Janicki, Janicki Environmental, Inc. Wayne Magley, Florida Department of Environmental Protection Judy Ott, Charlotte Harbor National Estuary Program Joel Steward, St. Johns River Water Management District Peter Suscy, St. Johns River Water Management District Kenneth Weaver, Florida Department of Environmental ProtectionTechnical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

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### Con **tents**

1. EPA’s Proposed 2012 Rule for Numeric Nutrient Criteria .............................................. 1

1.1. Disclaimer ........................................................................................................................ 1

1.2. Scope and Purpose of this Document ............................................................................... 1

1.3. Foreword .......................................................................................................................... 2

1.4. Water Bodies Affected by the Rule .................................................................................. 3

1.5. General Conceptual Model of Nutrient Pollution Causes and Effects ............................. 4

1.6. Summary of Classification and Segmentation of Waters ................................................. 6

1.7. Outline to the Technical Support Document .................................................................... 7

1.8. References ........................................................................................................................ 8



### Figure

Figure 1 -1. Conceptual model of nutrient pollution causes and effects ..........................................5



### Table

Table 1 -1. Water bodies affected by the proposed regulation .........................................................7Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

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### 1. **EPA’s Proposed 2012 Rule for N**  **umeric Nutrient Criteria** 

**1.1. Disclaimer** 
This document is intended to support the U.S. Environmental Protection Agency’s (hereafter EPA or the Agency) numeric nutrient criteria proposed on November 30, 2012, pursuant to section 303(c)(4) of the Clean Water Act (CWA) (Title 40 of the Code of Federal Regulations [ CFR ] section 131.43). The information provided herein does not substitute for the CWA or

EPA ’ s regulations; nor is this document a regulation itself. Thus, this document cannot, and does not, impose any legally binding requirements on EPA, states, authorized tribes, the regulated community, or any other party, and might not apply to a particular situation or circumstance.



### 1.2. **Scope and Purpose of this Docu**  **ment**

This document contains the scientific information that EPA used to derive numeric nutrient criteria for Class I, II, and III Florida waters that include estuarine , coastal, and south Florida inland flowing waters proposed on November 30, 2012, pursuan t to s ection 303(c)(4) of the CWA (40 CFR 131.43), hereafter proposed rule. EPA developed these numeric nutrient criteria

to protect Florida’s designated uses for estuari ne, coastal, and south Florida inland flowing waters from the effects of nutrient pollution.

For the purpose of this proposed rulemaking, EPA has identified six separate c lasses of waters : estuaries, tidal creeks, marine lakes, coastal waters , south Florida marine waters, and south
Flo rida inland flowing waters. Florida’s use designation for waters covered by this proposed rule include the following ( Section 62-302.400, Florida Administrative Code [ F.A.C.]):

• Class I waters are designated for potable water supplies

• Class II waters are de signated for shellfish harvesting

• Class III waters are designated for recreation, propagation and maintenance of a healthy,
well -balanced population of fish and wildlife

Specifically, EPA has derived these numeric nutrient criteria to interpret Florida’ s e xisting
narrative criterion for nutrients, applicable to waters with the uses listed above , at Subsection 62-302.530(47)(b), F.A.C.:

In no case shall nutrient concentrations of a body of water be altered so as to
cause an imbalance in natural populations of aquatic flora or fauna.

This document consists of chemical, physical, and biological data, metadata, methods, and analyses that EPA used to derive the proposed numeric nutrient criteria to interpret Florida’s existing narrative criterion , while being consistent with the objective of the CWA to restore and maintain the chemical, physical and biological integrity of our nation’s waters

.Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

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### 1.3. **Foreword**
Excess nitrogen and phosphorus, or nutrient pollution, are a leading cause of water quality degradation in the n ation ’s waters. Nutrient pollution can result in harmful algal blooms, reduced water clarity and loss of seagrass habitats, fish kills, oxygen -starved hypoxic or dead zones, and public health concerns related to impaired drinking water sourc es and increased exposure to toxic microbes such as cyanobacteria. Nutrient pollution problems can exhibit themselves locally or further downstream leading to degraded water quality in lakes, reservoirs, estuaries, and
coastal waters

.

One way nutrient poll ution can be managed effectively is by develop ing and adopting numeric nutrient criteria into state water quality standards, and then implement ing those water quality standards. State water quality standards are the foundation for protecting the quality of the

n ation ’ s surface waters and are the cornerstone of the water quality -based control program mandated by the CWA. Water quality standards describe the desired condition of a water body and consist of the following three principal elements: (1) the designated uses of the state ’ s waters (e.g., fishing, aquatic life, recreation ); (2) criteria specifying the amounts of various pollutants that may be present in those waters that will protect the designated uses; and (3) anti -degradationpolicies providing for protection of existing water uses and limitations on degradation of highquality waters ( see 40 CFR 131, Subparts A, B, C).

As noted in Section 1.2 , Florida has defined the designated uses of its estuari n e, coastal, and south Florida inland flowing waters as follows: Potable Water Supply (Class I), Shellfish Harvesting (Class II), or Recreation, Propagation and Maintenance of a Healthy, Well-Balanced Population of Fish and Wildlife (Class III) ( Section 62-302.400, F.A.C.). Florida’ s existing water quality criteri on for nutrients is expressed as a narrative at Subsection 62-302.530(47) (a) and (b), F.A.C. Subsection 62 -302.530(47)(b), F.A.C. provides the following:

In no case shall nutrient concentrations of a body of water be altered so as to
cause an imbal ance in natural populations of aquatic flora or fauna.

One advantage of numeric nutrient criteria compared to narrative criteria, once adopted and implemented, is that s tates can use the numeric criteria in quantitative state water quality
assessments and watershed protection management activities. Numeric nutrient criteria support
National Pollut ant Discharge Elimination System permits and total maximum daily loads for nutrients. They can also be used in state- and community -developed environmental baselin es to measure progress and support partnerships on the basis of activities , such as nutrient trading, land stewardship, and urban stormwater runoff control strategies.

W ater quality criteria consist of the following three key components: magnitude, duration, and frequency. Criteria must contain sufficient constituents to be protective of the designated use and must be based on a sound scientific rationale (40 CFR 131.11(a)). When setting water quality standards, the water quality standards of downstream wat ers also must be taken into
consideration to ensure that those downstream standards are attained and maintained (40 CFR 131.10(b)). In previously published guidance, EPA generally recommends that states develop and adopt numeric nutrient criteria for two c ausal parameters —such as total nitrogen ( TN ) and total phosphorus (TP), and two response parameters, such as chlorophyll a (chl -a) and water clarity —in their water quality standards to protect against the effects of nutrient pollution.Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

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### 1.4. **Water Bodies Affecte**  **d by the Rule** 
EPA’s proposed rule applies to estuaries, tidal creeks, marine lakes, coastal waters , and south
Florida inland flowing waters that have been classified by Florida as Class I (Potable Water Supplies), Class II (Shellfish Propagation or Harvesting)

, or Class III (Recreation, Propagation
and Maintenance of a Healthy, Well -Balanced Population of Fish and Wildlife).

This proposed rule also excludes the newly -approved State water quality standards that apply to Clearwater Harbor/St. Joseph Sound, Tampa Bay, Sarasota Bay, and Charlotte Harbor/Estero Bay ; wetlands ( including sloughs in south Florida that have been defined as wetlands by the

State ); flo wing waters within the lands of the Miccosukee and Seminole Tribes, Everglades
Protection Area , or Everglades Agricultural Area; Class III limited waters ; 1 and Class IV waters

, as covered by Section 62-302.400 F.A.C.

On June 13, 2012, FDEP submitted new an d revised water quality standards for review by EPA pursuant to section 303(c) of the CWA. These new and revised water quality standards are set out primarily in Rule 62-302 of the F.A.C. [Surface Water Quality Standards]. FDEP also
submitted amendments to Rule 62-303, F.A.C. [Identification of Impaired Surface Waters], which sets out Florida’s methodology for assessing whether waters are attaining State water quality standards. On November 29, 2012, EPA approved the provisions of these rules submitted
for review that constitute new or revised water quality standards (referred to in this TSD as the “newly

- approved State water quality standards”).

Among the newly- approved State water quality standards are numeric criteria for nutrients that apply to a set of estuaries and coastal marine waters in Florida. Specifically, these newly

approved State water quality standards apply to Clearwater Harbor/St. Joseph Sound, Tampa Bay, Sarasota Bay, Charlotte Harbor/Estero Bay, Clam Bay, Tidal Cocohatchee River/Ten Thousand Islands, Florida Bay, Florida Keys, and Biscayne Bay. Under the Consent Decree, EPA is relieved of its obligation to propose numeric criteria for these waters.

In some areas a gap may exist between maps used by Florida and EPA to show where criteria

ap ply. In areas where a gap exists between EPA’s proposed criteria and Florida’s numeric
crit eria, EPA proposes that Florida’ s numeric criteria from the adjacent estuary or marine segment apply (see Section 62 -302.532, F.A.C. for values). EPA proposes th at Florida’ s criteria from the northernmost segment of Clearwater Harbor/St. Joseph Sound (Subsection 62-302.532(a)1., F.A.C.) apply to the waters between that segment and the southernmost segment of EPA ’s Springs Coast estuary system. EPA proposes that Flori da’s numeric criteria from the northernmost segment of Biscayne Bay (Subsection 62-302.532(h)5., F.A.C.) apply to the waters of the intercoastal waterway between that segment and the southernmost segment of EPA’s Lake Worth Lagoon estuary system.

1 Class III limited waters include waters that support fish consumption; recreation or limited recreation; and/or propagation and
maintenance of a limited population of fish and wildlife ; for more details, see Subsection 62

- 302.400(1), F.A.C.Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

4 In other areas a gap may exist within estuaries covered by Florida's numeric criteria. In these areas, EPA proposes that Florida’ s criteria from the adjacent estuary or marine segment to the south apply to that gap. EPA proposes that Florida’ s criteria from (1) th e upper Lemon Bay segment (Subsection 62-302.532(d)2., F.A.C.) apply to the segment between the upper Lemon Bay segment and the Dona/Roberts Bay segment (Subsection 62-302.532(d)1., F.A.C.), (2) the Tidal Cocohatchee River segment (Subsection 62-302.532(e)1., F.A.C.) apply to the waters between the Tidal Cocohatchee River segment and the Estero Bay segment (Subsection 62

- 302.532(d)9., F.A.C.), (3) the Clam Bay segment (Subsection 62-302.532(j), F.A.C.) apply between the Clam Bay segment and the Tidal Cocohatchee River segment (Subsection 62- 302.532(e)1., F.A.C.), and (4) the Naples Bay segment (Subsection 62- 302.532(e)4., F.A.C.) apply to the segment between the Naples Bay segment and the Clam Bay Segment (Subsection 62-302.532(j), F.A.C.).



### 1.5. **General Conceptua**  **l Model of Nutrient Pollution Causes and Effects**
Nutrient pollution in water bodies comes from point sources and both urban and agricultural nonpoint sources, which may be either direct inputs to estuaries and coastal waters from large populations that reside close to their shores or transported loads delivered from watersheds.
Estuaries and coastal waters are especially vulnerable to nutrient pollution because they receive nutrient loads from multiple natur al and anthropogenic sources, often have sufficien t resident time for nutrient effects to manifest, and include multiple nutrient

- sensitive biological endpoints.

Nutrient pollution can adversely affect aquatic life in many different ways ( Figure 1-1 ). As
summarized in EPA’s Methods and Approaches for Deriving Numeric Criteria for Nitrogen/Phosphorus Pollution in Florida’s Estuaries, Coastal Waters, and Southern Flowing

Waters (USEPA 2010), the effects of nutrient pollution generally begin with effects on the primary producers in aquatic systems (e.g., increased algal growth and changes in algal species composition, including nuisance algal blooms) that increase organic matter inputs to the water body. Common secondary effects include loss of submerged aquatic vegetation, low dissolved oxygen ( DO ), and decreases in secondary production by sensitive species (USEPA 2006, 2008).Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

5 Figure 1-1 . Conceptual model of nutrient pollution causes and effectsTechnical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

6 Environmental consequences from changes in primary production (e.g., increases in phytoplankton) can include increased turbidity and decreased light penetration (Boyer et al.

2009 ; Bricker et al. 2007, 2008; McPherson and Mille r 1994). Reduced light availability often impacts growth and survival of habitats defined by submerged aquatic vegetation, which has a relatively high light requirement ( Lee et al. 2007 ; Dennison 1987 ; Duarte 1991) . Seagrasses are critical components of ma ny estuarine and coastal systems because many aquatic species use them as preferred habitats for feeding, spawning, and nursery grounds (Waycott et al. 2009).

Imbalances in primary producer dynamics can cause changes in habitat and available food resources, eventually affecting entire food web s (Bricker et al. 2003 ; Vitousek et al. 1997). Increased phytoplankton abundance may be associated with changes in composition (Paerl 1988), potentially including blooms of individual species that are unpalatable for grazers. Because excess nutrients cause changes at the lowest trophic levels of the ecosystem, they can cause a cascade of problems.

Excessive algal growth contributes to increased incidences of low oxygen, potentially reducing oxygen to levels below those needed for aquatic life to survive (NOAA 2010 ; USGS 2010). This occurs because primary production is often decoupled spatially or temporally from the resulti ng organic matter decomposition . Low oxygen concentrations, or hypoxia, can occur in episodic

even ts, which sometimes develop overnight. Migration to avoid hypoxia depends on species’ mobility, availability of suitable habitat, and adequate environmental cues for migration. For example, mobile species such as adult fish, can sometimes survive by moving to areas with more oxygen availability. Less mobile or immobile species, such as oysters and mussels, cannot move to avoid low oxygen and may perish during hypoxic events (Ecological Society of America 2009) . While certain mature aquatic animals can toler ate periods of lower DO, animals in immature life stages may be more sensitive to low oxygen (USEPA 2000). Sustained low levels of DO cause a severe decrease in the amount of aquatic life in hypoxic zones and affect the ability of aquatic organisms to find necessary food and habitat. Anoxia, defined as a complete lack of oxygen, presents the additional hazard in marine environments of increase d production of hydrogen sulfide gas , which is highly toxic to marine life. Hydrogen sulfide is produced by
anaerobi c processes in marine sediments and under oxic conditions is recycled within sediments. However hydrogen sulfide is able to diffuse into anoxic water, increasing the impact on marine life. Because most plants and aquatic organisms can not live without suffi cient oxygen, hypoxic
and anoxic areas are sometimes referred to as dead zones (Ecological Society of America 2009).

Estuaries and coastal waters are often valued for recreational uses such as swimming, diving, kayaking, fishing and shellfish harvesting. B ecause of the effects of excess nutrients on algae, water clarity , and aquatic life, nutrients may impair or degrade these human uses of the
ecosystem. Blooms of harmful algae can cause direct human health impacts on individuals who
are on or near affected waterways.



### 1.6. **Summary of Classification and Segmentation of Waters**

Estuaries outside south Florida were classified into 23 systems . As noted in Section 1.4, Florida has numeric nutrient criteria for some of the water bodies covered by this classification. As a result, EPA is proposing criteria for 19 of the 23 estuarine systems in addition to the three coastalTechnical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

7 systems. Segmentation res ulted in 89 estuarine segments among the 19 estuarine systems (see Volume 1: Estuaries, Section 1.3).

Coastal waters were delineated into three main regions to identify segments with similar physical and optical properties. These regions were further subdivided (see Volume 2: Coastal Waters, Section 1.3), and criteria were proposed for 71 segments.

For south Florida inland waters, EPA’s approach and an alternative approach are presented in Volume 3: South Florida Inland Flowing Waters.

See Table 1 -1 for a summary of the Florida water bodies including estuaries, tidal creeks, and marine lakes (TSD Volume 1), coastal waters (TSD Volume 2), and South Florida inland flowing waters (TSD Volume 3).

Table 1 -1 . Water b odies a ffected by the p roposed r egulation

Vol. Water Body Type Geographic Characteristic Key Water Bodies

1 Estuaries Estuaries outside s outh

Florida a Perdido Bay Pensacola Bay Choctawhatchee Bay St. Andrews Bay St. Joseph Bay Apalachicola Bay Alligator Harbor Ochlockonee Bay Big Bend a

Suwannee Sound
Springs Coast Lake Worth Lagoon/

Loxahatchee
St. Lucie Estuary Indian River Lagoon

Halifax River Guana, Tolomato, Matanzas, Pellicer System

St. Johns River Nassau River/Big Talbot St. Marys River/Amelia River

Tidal Creeks Predominantly marine waters that are subestuaries or upstream of larger estuaries that exhibit a wide range of salinity zones typical of larger estuaries but on a smaller scale. ( Excludes waters classified elsewhere)

. Marine Lakes Marine lakes are coastal lakes with intermittent or groundwater connections to marine water, and include dune and solution (rockland) lakes.

2 Coastal Waters b Predominantly marine waters extending from land seaward

3 nautical miles Florida Panhandle

West Florida Shelf

Atlantic Coast

3 South Florida

Inland Waters Class I and III inland flowing freshwaters in the South Florida Nutrient Watershed Region, not including the Ev erglades Protection Area and Everglades Agricultural Area

a Includes coastal waters extending from Apalachicola to Clearwater Harbor/St. Joseph Sound

b Excludes coastal waters extending from Apalachicola to Clearwater Harbor/St. Joseph Sound as well as south Florida marine

waters



### 1.7. **Outline to the**  **T echnical**  **S upport**  **D ocument** 

Details on the methodology EPA used to derive numeric nutrient criteria for estuaries outside of south Florida is provided in Volume 1: Estuaries , Section 1, and the resulting criteria and downstream protection values are in the estuary

- specific results ( Section 2). Background on each estuarine system is in Appendix A. D etails of the stressor

- response analyses are in Appendix B. Appendix C contains details of the watershed proce dures. Details of the est uary modeling procedures are found in Appendi ces D and E. Appendix G contains additional information about alternative numeric nutrient criteria methodologies for several estuaries.Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

8 For tidal creeks, the details on how EPA derived criteria are described in Volume 1: Estuaries,
Section 3.1.

For marine lakes, the approach to derive criteria is described in Volume 1: Estuaries, S ection 3.2 and Appendix F.

For coastal waters, t he approach used to derive criteria is in Volume 2 : Coastal Waters

, S ection 1, and the resulting criteria can be found in Section 1.6. Background information on the current conditions of the coastal regions is in Appendix A, and Appendix B contains supporting documentation for the remote sensing methods used to der ive criteria for coastal segments.

For south Florida inland flowing waters, the approach for deriving downstream protection values that manage nutrient pollution upstream and protect marine waters downstream a re presented in Volume 3, S ection 2. An alterna te analysis in which EPA is considering deriving in

- stream TN
and TP criteria for south Florida inland flowing waters is in Volume 3, Section 3.



### 1.8. **References**
Boyer, J.N., C.R. Kelble, P.B. Ortner, and D.T. Rudnick. 2009. Phytoplankton bloom status: Chlorophyll a biomass as an indicator of water quality condition in the southern estuaries of Florida, USA. Ecological Indicators 9(6, Supplement 1):S56-S67.

Bricker, S.B., J.G. Ferreira, and T. Simas. 2003 . An integrated meth odology for assessment of estuarine trophic status. Ecological Modelling 169(1):39-60.

Bricker, S., B. Longstaff, W. Dennison, A. Jones, K. Boicourt, C. Wicks, and J. Woerner. 2007. Effects of Nutrient Enrichment In the Nation’s Estuaries: A Decade of Chan ge. NOAA Coastal Ocean Program, National Centers for Coastal Ocean Science, Decision Analysis Series No. 26, 328, Silver Spring, MD.

Bricker, S.B., B. Longstaff, W. Dennison, A. Jones, K. Boicourt, C. Wicks, and J. Woerner.

2008 . Effects of nutrient enrich ment in the nation's estuaries: A decade of change. Harmful Algae 8(1):21-32.

Dennison, W.C. 1987. Effects of light on seagrass photosynthesis, growth and depth distribution. Aquatic Botany 27:15-26.

Duarte, C.M. 1991. Seagrass depth limits. Aquatic Botany 40(4):363-377.

Ecological Society of America. 2009. Hypoxia

. http://www.esa.org/education/edupdfs/hypoxia.pdf

. Accessed December 2009.

Lee, K. -S., S.R. Park, and Y.K. Kim. 2007 . Effects of irradiance, temperature, and nutrients on growth dynamics of seagrasses: A review. Journal of Experimental Marine Biology and Ecology 350(1-2):144-175.

McPherson, B.F., and R.L. Miller. 1994. Causes of Light Attenuation in Tampa Bay and Charlotte Harbor, S outhwestern Florida. Water Resources Bulletin 30(1):43-53.Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria,
Introduction

9 NOAA. 2010. Harmful Algal Blooms: Current Programs Overview . Center for Sponsored Coastal Ocean Research, National Oceanic and Atmospheric Administration. http://www.cop.noaa.gov/stressors/extremeevents/hab/default.aspx

. Accessed September

2010.

Paerl, H.W. 1988. Nuisance phytoplankton blooms in coastal, estuarine, and inland waters. Limnology and Oceanography 33(4):823-847.

USEPA. 2000. Ambient Aquatic Life Water Quality Criteria for Dissolved Oxygen (Saltwater): Cape Cod to Cape Hatteras . U.S. Environmental Protection Agency, Office of Water,

PA -822-R-00-012, Washington D.C.

USEPA. 2006. National Estuary Program Coastal Condition Report

. EPA -842-B-06-001.
U.S. Environmental Protection Agency, Office of Water and Office of Research and Development.

USEPA. 2008. National Coastal Condition Report III . U.S. Environmental Protection Agency,
Office of Water and Office of Rese arch and Development.

USEPA. 2010. Methods and Approaches for Deriving Numeric Criteria for Nitrogen/Phosphorus Pollution in Florida’s Estuaries, Coastal Waters, and Southern Inland Flowing Waters . U.S. Environmental Protection Agency. http://yosemite.epa.gov/sab/sabproduct.nsf/fedrgstr_activites/C439B7C63EB9141F85257 73B004E53CA/$File/FL +EC+Final+Methods+

- +Chapters1 -6.pdf . Updated November 17, 2010.

USGS. 2010. Hypoxia . U.S. Geological Survey. http://toxics.usgs.gov/definitions/hypoxia.html

. Accessed September 2010.

Vitousek, P.M., J.D. Aber, R.W. Howarth, G.E. Likens, P.A. Matson, D.W. Schindler, W.H. Schlesinger, and D.G. Tilman. 1997 . Human alteration of the global nitrogen cycle: Sources and consequences. Ecological Applications 7(3):737-750.

Waycott, M., C.M. Duarte, T.J.B. Carruthers, R.J. Orth, W.C. Dennison, S. Olyarnik, A. Calladine, J.W. Fourqurean, K.L. Heck, A.R. Hughes, G.A. Kendrick, W.J. Kenworthy, F.T. Short, and S.L. Williams. 2009 . Accelerating loss of seagrasses across the globe threatens coastal ecosystems. Proceedings of the National Academy of Sciences of the United States of America 106(30):12377-12381.