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# Choctawhatchee Bay Blake Schaeffer, Ph.D. U.S. Environmental Protection Agency Robert J. Livingston, Ph.D. Florida State University Shelley Alexander Northwest Florida Aquatic PreserveOffice of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 1 

## Overview
• 

## Blake Schaeffer

– Description/History

– Land Use/Land Cover

– N Yield and N Budget

– Optics and Remote Sensing • 

## Skip Livingston

– Impacts of anthropogenic nutrient loading • 

## Shelley Alexander

– Effects of nutrients on seagrassOffice of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division Photo image area measures 2” H x 6.93” W and can be masked by a collage strip of one, two or three images. The photo image area is located 3.19” from left and 3.81” from top of page. Each image used in collage should be reduced or cropped to a maximum of 2” high, stroked with a 1.5 pt white frame and positioned edge -to- edge with accompanying images.

March 15, 2010 Blake Schaeffer, Jeff Jackson US EPA, Gulf Breeze, FL 

# Choctawhatchee Bay

Photos: basinalliance.orgOffice of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 3 

## Description of Choctawhatchee Bay

• 

### Counties: Holmes, Washington, Okaloosa and Walton • 

### Cities: Destin, DeFuniak Springs, and Niceville • 

### Area: 340 km 2 

### • 

### Mean depth: 3.8 m • 

### Watershed: 13x10 3 

### km 2



### – 91% of which is Choctawhatchee River • 

### Salinity range 0 to 32Office of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 4 

## Choctawhatchee Bay 1992-2007 Seagrass CoverageOffice of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 5 

## Historical Perspective

• 

### Broad floodplain with seasonal flooding

– 13 major floods of Choctawhatchee River in last century • 

### 4th 

### longest river in Florida and 3 rd 

### largest in annual discharge • 

### Rivers and tributaries receive ground water from springs of Florida Aquifer. • 

### Home to:

– Okaloosa darter • 

### U.S. Fish and Wildlife • 

### Proposed to reclassify Endangered - >Threatened

– Gulf sturgeon • 

### Combined population growth of surrounding counties was 23% in 10 years from 2000 Census.

• Source: Northwest FL Water Management DistrictOffice of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 6 

## Choctawhatchee Bay Watershed Land- Use/Land -Cover
• 

### Choctawhatchee Watershed Florida land use, cover and form classification system (FLUCC)

5x10 3 

### km 2 

### (43.2% – Upland Forests) 2x10 3 

### km 2 

### (20.1% - Agriculture) 2x10 3 

### km 2 

### (15.7% - Wetlands) 1x10 3 

### km 2 

### (10.3% - Rangeland) 862 km 2 

### ( 6.2% - Urban and Built Up) 498 km 2 

### ( 3.6% - Water) 56 km 2 

### ( 0.4% - Barren Land) 58 km 2 

### ( 0.4% - Transport, Utilities, etc) 13x10 3 

### km -2 

### TotalOffice of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 7



## Nitrogen Input Budget for Choctawhatchee Bay - estimated via USGS regional SPARROW model
• 

### TN loading rate for Choctawhatchee Bay: 1x10 6 

### kg N y-1 

### (41% - Atmospheric Deposition) 1x10 6 

### kg N y-1 

### (31% - Fertilizer) 7.9x10 5 

### kg N y-1 

### (19% - Manure) 1.9x10 5 

### kg N y-1 

### ( 5% - Urban) 1.3x10 5 

### kg N y-1 

### ( 3% - Point Sources) 4x10 6 

### kg N y-1 

### (Total)Office of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 8



## Nitrogen Input Budget for Choctawhatchee Bay – estimated via USGS regional SPARROW model • 

### TN loading rate for Choctawhatchee Bay: 3x10 6 

### kg N y-1 

### (94.3% - Choctawhatchee River) 7.6x10 4 

### kg N y-1 

### ( 1.9% - Lafayette Creek) 6.3x10 4 

### kg N y-1 

### ( 1.6% - Alaqua Creek) 3.5x10 4 

### kg N y-1 

### ( 0.9% - Rocky Creek) 3.2x10 4 

### kg N y-1 

### ( 0.8% - Turkey Creek) 1.7x10 4 

### kg N y-1 

### ( 0.4% - Basin Creek)

8x10 3 

### kg N y-1 

### ( 0.2% - Swift Creek) 4x10 6 

### kg N y-1 

### Total

• 

### 3x10 6 

### kg N y-1 

### Monitored TN loading from the Choctawhatchee River from 1999 -2004.Office of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 9 

## Total Nitrogen Yield from Choctawhatchee Bay Watershed - estimated via USGS regional SPARROW model
• 

### Estimate of TN yield for watershed is 314 kg/km 2

### /y. • 

### Ag sources, including Fertilizer and Manure are the largest anthropogenic sources in the watershed, accounting for 50% of total inputs. • 

### Anthropogenic sources in watershed contribute 58% of TN loading. kg km -2 y-1Office of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 10 

### Optics and Remote SensingOffice of Research and Development National Health and Environmental Effects Research Laboratory, Gulf Ecology Division 11 

### Optics and Remote Sensing3/15/2010 12 

# IMPACTS OF ANTHROPOGENIC NUTRIENT LOADING IN COASTAL SYSTEMS OF THE EASTERN GULF OF MEXICO Choctawhatchee Bay Dr. Robert J. Livingston, Professor Emeritus Department of Biological Science Florida State University Tallahassee, Florida 32306 Email: livingstonr@comcast.net3/15/2010 13 

# River flow rates of major systems in NE Gulf Region3/15/2010 14 

# Nutrient loading characteristics of river systems in the eastern Gulf of Mexico. Data

are mean values of monthly sampling over 21 month period during years noted below.3/15/2010 15 

# Comparison of physical/chemical water and sediment factors in highly productive upper bay areas Data were taken during July in the various bays3/15/2010 16 

# Comparison of plankton assemblages before and after anthropogenic nutrient loading in upper Perdido Bay3/15/2010 17 

### Averaged data showing trophic organization of bays in NE Gulf of Mexico. Data include herbivores, omnivores, C1 carnivores, C2 carnivores, and C3 carnivores that represent biomass of Fishes, infauna, and epibenthic invertebrates (FII) taken per m 2 

### at upper bay stations monthly over the periods indicated .3/15/2010 18 

### CHOCTAWHATCHEE BAY
• Human activities associated with urbanization (e.g., storm water runoff and sewage spills) have contributed to the deterioration of the Choctawhatchee Bay system.

• The combination of nutrient loading and salinity stratification contributed to periodically severe water quality problems (hypoxia, anoxia) and associated reductions of natural productivity in affected sections of the bay.
• Continued urban development in western sections of the bay has been associated with increased urban stormwater runoff and sewage leaks leading to advanced hypereutrophication( hypoxia at depth, fish kills, mammal deaths) and reduced secondary production along with novel extensive red tide ( **Karenia breve** ) blooms in bay and offshore areas. • • There was a serious problem in the form of the deaths of sea turtles and hundreds of “bottlenose dolphins” in the Choctawhatchee system and along the coast between Choctawhatchee Bay and St. Andrews Bay. Deaths of some fish -eating terrestrial mammals such as raccoons and foxes in the region were also observed.
• Long -term, ecosystem - level studies of the Choctawhatchee system are needed to determine the extent of the bloom impacts and to devise effective management of the nutrient loading problems in the bay. Both river loading and urban bayou runoff should be the focus of any such studies.3/15/2010 19 

# Factors Sampled in Field Studies of Choctawhatchee River- Bay System (1985- 1989) A detailed, ecosystem - level analysis was carried out in the Choctawhatchee River and Bay by our research group. The following factors were analyzed. • River flow, rainfall • Salinity, conductivity, temperature, dissolved oxygen,oxygen anomaly, pH, Secchi • Water quality and loading nutrients: NH3, NO2, NO3, TIN, PON, DON, TON, TN, PO4, TDP, TIP, POP, DOP, TOP, TP. • Other water quality factors: DOC, POC, TOC, IC, TIC, TC, BOD. SiO2, TSS, TDS, DIM, DOM, POM, PIM. NCASI color, turbidity, Chlorophyll a, • Water/sediment pollutants (metals) • Submerged aquatic vegetation analyses (quadrats) and transplants • Whole water and net phytoplankton (nets, whole water) • Infaunal macroinvertebrates (ponars, cores) • Invertebrates (seines, trawls) • Fishes (seines, trawls) • Food web transformations (based on stomach contents of fishes and invertebrates)

•3/15/2010 203/15/2010 21 

# Choctawhatchee River Water quality data, together with the conductivity levels, indicate periodic deterioration in Pine Log Creek, Seven Run Creek, Bruce Creek, and Wright's Creek. Clear cutting and sewage discharges were noted in various parts of the drainage, but water quality in the main river was generally good.
• Riverine phytoplankton abundance in the Choctawhatchee system is associated with stream size, flow rates, and possibly the wetlands vegetation. The abundance of microalgae in the main channel stations was low relative to most of the river tributaries There was a basic dichotomy of habitat distribution between the various tributaries of the system and the main stem of the river. Spatial and temporal river flow and water quality differences were noted in addition to differences of sediment characteristics.

• Infaunal macroinvertebrates were comparatively depauperate in numbers and species richness in the main stem of the river. • • Temporal differences in the distribution of epibenthic macroinvertebrates were noted between the tributaries and the main channel. The fishes were fewer in number and species richness in the tributaries than the main stem. Such basic differences in fish assemblages were ascribed to varying patterns of habitat distributions. 

# •3/15/2010 22 

# Nutrient loading, bay habitat response and associated food web disruptions • The Choctawhatchee Bay system is a large, highly complex series of habitats that is strongly influenced by freshwater input (river, bayou drainages), the single entrance to the gulf (East Pass), and the physiographic structure of the bay. These have combined to cause low turnover rates, vertical salinity stratification in central and western sections, and associated habitat deterioration due to hypoxia/anoxia.

• High salinities and associated stratification accompanying the opening of East Pass nearly a century ago together with various other human activities (urbanization, storm water runoff, sewage dischrages) have contributed to the deterioration of the natural aquatic resources in the bay.

• Critical, highly productive habitats include the few remaining estuarine wet-lands (emergent vegetation), the shallow submerged aquatic vegetation (Halodule beds), the river mouth (and associated freshwater wetlands), and the various (unpolluted) bayous.

• Although river loading of various nutrients was relatively high compared to other systems, the primary problem of anthropogenic nutrient loading appeared to be centered in urban lagoons. For example, the situation in Old Pass Lagoon combines loading of nutrients and organic matter and a lack of flushing to cause water quality problems (hypoxia, anoxia) and associated reductions of natural productivity. This has led to high nutrients (N, P) in the water column, silt-laden sediments, high phytoplankton productivity, low numbers of herbivores (zooplankton, meroplankton), a depauperate infaunal invertebrate community and relatively few epibenthic invertebrates and fishes.

• The Old Pass Lagoon conditions are typical of a number of the urban lagoons in the bay. This situation is also found in parts of the western bay areas affected by high salinity stratification.

• The relationship of nutrient concentration and nutrient loading remains complex, and this aspect of the cause of damaging blooms needs to be examined.

•3/15/2010 23 Salinity stratification and bottom hypoxia: The opening of East Pass in the early 20th century allow salt water to infiltrate the bay. This has led to periodic salinity stratification, isolation of the bottom waters from surface interactions, and reduced dissolved oxgyen in affected parts of the bay. This represents one reason for the relatively low benthic productivity of the bay.3/15/2010 24 

# Comparison of dissolved oxygen conditions in Alaqua Bayou (C9) and Garnier Bayou (C40)3/15/2010 25 Project: Phytoplankton from Choctawhatchee Bay, Florida (Poquito Bayou Mouth, Hand’s cove, Garnier Bayou, South Shalimar yacht Club, Chula Vista Bayou, Marker 61, East Pass. Date of Collection: 04-04-2006 Date received:04-05 -2006
• A.K.S.K. Pasad

• A potentially harmful diatom, Pseudonitzschia (possibly pseudodelicatissima) sp. was • present in almost all of the stations examined. Cyclotella choctawhatcheeana and • Chaetoceros laevis were also present. Dinoflagellates, Prorocentrum triestinum, • Prorocentrum micans and Prorocentrum cordatum (syn. P. minimum ) were present • in low numbers. All three species are known to form red tide discolorations.

• According to Manual of Harmful Marine Microalgae (Hallegraeff et al. 2003), • increasing numbers of Pseudonitzschia species are being found to produce • domoic acid, a toxin that causes Amnesic Shellfish poisoning (ASP). • Karenia brevis was not observed • There has not been a systematic analysis of the phytoplankton assemblages of the bay. The primary concern with red tide (Karenia brevis ) ignores the inportance of other bloom species that can have major adverse effects on bay food webs.3/15/2010 26 

# Adverse Effects of nutrients on Seagrass Distribution in Choctawhatchee Bay Presented by: Shelley Alexander Northwest Florida Aquatic Preserve3/15/2010 27 

# Coverage of Seagrass between 1992- 2003 from USGS aerials3/15/2010 28 

# Western Choctawhatchee Bay 1992- 2003 seagrass coverage change3/15/2010 29 

# Uncorrected chl a values East Choctawhatchee Bay ug/l3/15/2010 30 

# Uncorrected chl a values for West Choctawhatchee Bay 

# ug/l3/15/2010 31 

# Contributing factors to decline in Seagrass coverage within Choctawhatchee Bay 

# • Historical algal blooms caused by over nutrification from STP and NPS 

# • One year flushing time 

# • Sediment quality (chemical contamination and high organic silts)