section II North Florida as a Microcosm of the Restoration Paradigm North Florida is one of the last areas in the United States where low population levels, together with relatively little industrial development, have contributed to some of the least polluted aquatic areas in the world. This includes lakes, springs, rivers, and coastal areas that remain pristine in every sense of the word. Spring-fed lakes are unique in terms of the relationship with the karst geological organization of the aquatic landscapes. Springs abound in this region, and are primary sources of clean, fresh water to the many rivers that eventually drain into an untouched series of estuaries in the Gulf of Mexico. Because of the relatively low levels of population and pollution, the impacts of a growing human population are more easily determined. Long-term research in these areas has thus led to various conclusions regarding the impacts of urbanization, agricultural development, and industrial wastes on aquatic resources of the region. 1966_book.fmPage11Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC 13 chapter 2 Cultural Eutrophication of North Florida Lakes Most lakes, rivers, and coastal areas do not get the publicity, or the scientific attention, that characterizes the better-known systems. Likewise, the cumulative impacts of complex combinations of human activities are rarely determined with adequate scientific informa- tion. Without such data, there is little chance that anything approaching full restoration can be achieved. This factor, the scientific approach to restoration, has not been lost on development interests and their counterparts in the news media. The complicated inter- play of scientific research, economic/political interests, and the role of the news media in environmental matters remains undermined despite the fact that these forces direct the fate of most aquatic systems in the United States. Over the past 16 years, we have conducted a series of studies concerning the impact (Livingston, 1988a, 1989a, 1992a, 1993a, 1995a,b,c, 1996a, 1997a,b, 1998a, 1999a,b). 2.1 Background of Solution (Sinkhole) Lakes Solution or sinkhole lakes are relatively common in areas dominated by limestones of north and central Florida. The dissolution of subsurface lime-rock forms a karst topogra- phy that, together with ample rainfall, provides the conditions of the infiltrated limestone environment (Northwest Florida Water Management District, 1992). Many karst systems in the southeastern United States are interconnected with springs, underground caverns or caves, and sinkholes so that groundwater is freely interconnected with surface water. The solution lake is thus directly connected to the surficial water table, and is dependent on seasonal and interannual drought–flood cycles. This situation is responsible for specific effects of storm water runoff on water and sediment quality that can be natural and/or anthropogenous (i.e., affected by human activities). The most important groups of solution lakes in the northern hemisphere occur in Florida (Hutchinson, 1951). Although various studies have been carried out in some northern Florida lakes, there have been virtually no comprehensive ecological analyses of these systems. The area is underlain by the Floridan Aquifer, which is the primary source of the groundwater (Hendry and Sproul, 1966). Recharge of the aquifer comes mostly from rain that moves through the aquifer and is discharged into numerous springs to the south. Solution lakes in north Florida are located primarily in the Tallahassee Red Hills (Leon County, Florida) as part of the Miocene–Pliocene delta plain that is characterized by streams, wetlands drainages, and sub-surface limestone (Swanson, 1991). In the Tallahassee 1966_book.fmPage13Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC of urban storm water on lakes in north Florida (Figure 2.1). The long-term data were taken using methods outlined in Appendix I. The data were released as a series of public reports 14 Restoration of Aquatic Systems Hills, polje-like depressions are produced by sudden developments of sinks in the normal valleys. The part of the valley drained by the sink is then eroded, forming an elongate, closed basin (Hutchinson, 1951). With increasing erosion and deposition, the sinks are plugged, forming elongate basins that remain closed laterally. These solution lakes often have convoluted shorelines, and they experience periodic desiccation during drought periods as a product of the opening of the sink and/or the lowering of the water table. Examples of such lakes include Lakes Jackson and Lafayette. These lakes are thus subject to extremes in water level fluctuation due to the unique combination of precipitation trends and geomorphology of the region. The lakes of the north Florida region are usually small and relatively shallow (less than 10 m deep), and are controlled by various complex geological, morphological, and meteorological factors. There is considerable variation in the physiography of these lakes. The Lake Jackson Basin, about 25.8 km 2 (16.1 sq. mi.), includes the littoral zone and flood clay hill lake system with sinkholes. According to Wagner (1984), Lake Jackson has drained five times in the past 80 years. The steep-sided basin is closed, receiving input from urban storm water in the southeastern and southwestern sections and low-intensity agricultural commercial growth zone that contributes to the Lake Jackson drainage. Megginnis Arm, Ford’s Arm, portions of the western section of the lake, and Little Lake Jackson are most affected by the urban storm water runoff. During wet periods, groundwater and lake levels are high; and during dry periods, these levels go down. Inflow factors for Lake Jackson include rainfall, surface water runoff, Figure 2.1 Distribution of lake systems in north Florida that were part of the long-term studies by the Florida State University Study Group. Geographic data provided by the Florida Geographic Data Library (FGDL). Lake lamonia Lake Jackson Lake Talquin Lake Munson Lake Ella Lake Lafayette Lake Hall Lake McBride Lake Miccosukee 1966_book.fmPage14Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC plain of Lake Jackson, Little Lake Jackson, and Lake Carr (Figure 2.2) as an open-water, runoff in the north (Figure 2.3). Two major roads (I-10 and U.S. 27) are part of an extensive Chapter 2: Cultural Eutrophication of North Florida Lakes 15 and discharge from the Surficial Aquifer. These are also the primary sources of the input of nutrients and toxic substances. Water loss is dominated by evapo-transpiration and leakage either through the bottom or through a loss of water from the sinkholes. According to Wagner (1984), when the level of Lake Jackson reaches 82 ft or less, there is no real inflow, and losses to the groundwater control lake levels. Bottom leakage is insignificant compared to evaporation and transpiration. Loss due to bottom outflow is proportionately higher during prolonged drought. Losses of water through sinks in the lake are considered an important part of the declines in lake levels in recent times (Wagner, 1984). These ecological characteristics make lakes such as Jackson highly susceptible to adverse impacts due to urban storm water flows as the lake is in continuous contact with contaminated surface and groundwaters. Flushing rates (residence times) are important factors in the eutrophication potential of sinkhole lakes (Richey et al., 1978), and the average residence times of Florida lakes are about an order of magnitude greater than those of comparably sized lakes with rapid hydrological through flow. This indicates water-residence times of 1 to 5 years that are longer by an order of magnitude than those in lakes having rapid surficial runoff. This accounts for the vulnerability of many of the north Florida lakes to eutrophication and acidification (Deevey, 1988). When developing nutrient budgets in such systems, it is necessary to take the above facts into account with sediments, water, and the biota acting as primary nutrient sinks. Increased nutrient loading due to human sources such as sewage plant releases and storm water runoff, together with the relatively long retention times and high efficiency of nutrient recycling, all add to the susceptibility of solution lakes to cultural eutrophication. Figure 2.2 The Lake Jackson system in north Florida. Geographic data provided by the Florida Geographic Data Library (FGDL). LAKE JACKSON 27 10 WE N S Enlarged Area 1966_book.fmPage15Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC 16 Restoration of Aquatic Systems 2.2 Urban Runoff and Solution Lakes Although lakes have common driving components (nutrients, water and sediment quality, physical modifying factors, primary producers, predators/prey associations, trophic orga- nization), they behave as unique aggregations of these similar components (Richey et al., 1978). Differences in the response of a given lake system to urban pollutant loading are based on assimilative capacity as determined by physical dimensions and flushing rates. In general, solution lakes are essentially closed systems and, as such, are particularly sensitive to urban storm water runoff. Response to pollutant loading is primarily related to amount, timing, and qualitative composition of surface runoff and surficial groundwater contributions. Loading rates of nutrients, organic compounds, and toxic agents, as qualified by the assimilative capacity of a given lake, are thus crucial to the effects of such substances in systems that are either closed or have limited flushing capabilities. Johnson (1987), in a multivariate analysis of storm water runoff in Leon County, found that significant Figure 2.3 The Lake Jackson system in north Florida, showing long-term sampling stations. Arrows indicate main sources of urban runoff. Geographic data provided by the Florida Geographic Data Library (FGDL). Lake Jackson US 27 Scale mi km 012 012 3 3 Megginnis Arm I 10 Fords Arm Brill Pt. J02 J03 J08 J05 J10 J12 J16 J13 J15 J14 J11 N 1966_book.fmPage16Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC Chapter 2: Cultural Eutrophication of North Florida Lakes 17 predictors of runoff volume (in order of importance) are the extent of urban land (imper- meable surfaces, reduced wetlands, etc.), the percentage of clay in the soils (permeability), the overall drainage area, and the average slope of the basin. Evapo-transpiration and groundwater leakage also affect the response, but the essential accumulation of nutrients and toxic agents under such circumstances accounts for the high vulnerability of essen- tially closed solution lakes to inputs of nutrients, organic matter, and toxins. Various pollutants occur in sediments and animals in receiving areas associated with wastewater treatment plants and storm water runoff (Gossett et al., 1983). Bioaccumulation of pollutants has been associated with the n-octanol/water partition coefficients. Storm water has been associated with high concentrations of hydrocarbon contaminants known as polynucleated aromatic hydrocarbons (PAHs) (Wild et al., 1990a,b). These compounds are introduced into the environment in natural and anthropogenous combustion processes (Menzie et al., 1992). Polynucleated aromatic hydrocarbons are often found in areas affected by the incomplete combustion of organic materials such as coal, oil, natural gas, and wood. Aquatic systems concentrate PAHs through contaminants in the air and/or loading via the drainage basins. The association of urban pollutants and aberrant charac- teristics of aquatic organisms, including disease, has been well established. The highest frequency of diseased fishes often occurs in so-called “polluted” areas of aquatic systems. McCain et al. (1992) found that sediments and animals taken from areas receiving urban runoff in San Diego Bay were characterized by high levels of aromatic hydrocarbons and their metabolites when compared to areas that did not receive urban runoff. PAH con- tamination of sediments has been associated with various forms of fish disease, and PAH compounds can cause sufficient stress to cause susceptibility of fish to fatal parasite infestations. 2.3 Lake Ecology Program The Lakes Program was designed around a series of continuous field collections of data and field/laboratory experiments and analyses. Data were taken from 1988 to 1997 in Lake Jackson and from 1991 to 1997 in a series of other sinkhole lakes in the region (Lakes studies of the biological organization of Lake Jackson were carried out concerning phyto- plankton, submerged aquatic vegetation, zooplankton, infaunal macroinvertebrates, fishes, and trophic organization. The effects of PAHs on submerged aquatic macrophytes were also analyzed. Storm water quality analyses were carried out in addition to analyses in a series of treatment holding ponds. The primary objective of the project was to analyze the effects of urban storm water on lakes systems at various levels of biological organi- zation, and to evaluate seasonal and interannual changes in background habitat factors relative to the effects of urban storm water. These analyses were supplemented by pho- tographs and by underwater photography. The long-term field-monitoring program was integrated with a series of field and laboratory experimental programs to determine the effects of urban storm water runoff on Lake Jackson. 2.4 Urban Runoff and Lake Jackson 2.4.1 Background of years. The cultural peak of Native American occupation around the lake occurred between A.D. 1250 and A.D. 1500. During this time, along the southwestern shore of Megginnis Arm, a series of earthworks were constructed. This complex, composed of 1966_book.fmPage17Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC Lake Jackson (Figure 2.2 and Figure 2.3) has been a center of human activity for thousands Lafayette, Hall, Munson, McBride, and Ella and No-Name Pond; Appendix I). Detailed 18 Restoration of Aquatic Systems farmsteads, hamlets, and six pyramidal, flat-topped, truncated temple mounds, was con- structed and utilized by a Native American culture whose influence and settlements is designated an Outstanding Florida Water and an Aquatic Preserve by the state of Florida. These designations supposedly give legal protection to the lake, although there has been continuous, scientifically documented input of polluted water to the lake from road con- struction and urban development from the early 1970s to the present (Harriss and Turner, 1974; Livingston, 1993a, 1995a, 1997a, 1997b, 1999a). Until recently, Lake Jackson was famous throughout the country for its bass fishing. Bass grew faster and larger in Lake Jackson than in most other lakes in the country. The lake is a closed system with inputs from three major drainages: (1) Megginnis Creek (draining portions of the southern basin), (2) Ford’s Creek (draining portions of the Megginnis Arm Creek drains a major urbanized area characterized by malls, shopping centers, gas stations, a major interstate highway (I-10), and low- to high-density urban/res- idential developments. Ox Bottom Creek is a drainage area entering the northern part of Lake Jackson. Forested areas, light agriculture, and increasing encroachment by housing developments contribute to the storm water runoff in this area. The Ford’s Arm basin includes forested uplands, light agriculture, and rapid proliferation of urban housing. The northern extremity of the Jackson basin is managed primarily as an agricultural resource with cattle, timber, and low-intensity farming. Lake Jackson also has various forms of municipal development in the western sections that have led to water quality impacts from roads and various forms of urban development. A series of studies was carried out concerning the relationship of water quality in Lake Jackson as a consequence of urban sediment and nutrient loading. Harriss and Turner (1974) in a 3-year analysis of water quality measurements and phytoplankton productivity, noted frequent oxygen sags in Megginnis Arm and Ford’s Arm. Water quality was char- acterized by fair to poor water quality conditions with urban storm water runoff associated with low Secchi readings, high turbidity and conductivity, and high pH. Conductivity increased in Megginnis Arm over the period of study from about 40 to 100 µ mhos cm − 1 . Phosphorus and nitrogen concentrations were usually highest during winter periods in Megginnis Arm and Ford’s Arm. Heavy metals (Pb) and dissolved phosphorus were traced to commercial parking areas in the Megginnis Arm watershed. Affected lake areas had the highest phytoplankton productivity, with nannoplankton as the primary form. Megginnis Arm was characterized by low phytoplankton diversity and blue-green algae. Ecologically healthy northern and mid-lake areas were characterized by green algae, dinoflagellates, or chrysophytes. Studies by the Florida Game and Fresh Water Fish Commission (July 1975 to June 1976) indicated that the most common macro- phytes in Lake Jackson included water hyssop ( Bacopa caroliniana ), American lotus ( Nelumbo lutea ), spikerush ( Eleocharis baldwinii ), sagittaria ( Sagittaria stagnorum ), and maidencane ( Panicum hemitomon ). Introduced Hydrilla ( Hydrilla verticillata ) was starting to increase at this time (Babcock, 1976). Dominant infaunal macroinvertebrates included scuds (amphipods), oligochaete worms, and midge larvae (Chironomids). Phantom midge larvae, common in eutrophic waters, were found in Megginnis Arm, whereas the amphi- pods were largely absent in this area of the lake. Fletcher (1990) found that numbers of chironomid larvae were directly associated with dissolved oxygen (DO) levels in Lake Jackson. Mason (1977) found that water quality was significantly degraded in the southern parts of the lake (particularly Megginnis Arm) due to loading from the newly constructed I-10 highway and other portions of the urbanized basin through the lake. 1966_book.fmPage18Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC extended across much of the Southeast during this period. Today, Lake Jackson (Figure 2.2) southern basin), and (3) Ox Bottom Creek (draining the northeastern basin) (Figure 2.3). Chapter 2: Cultural Eutrophication of North Florida Lakes 19 Wanielista (1976), Wanielista et al. (1984), and Wanielista and Yousef (1985), using sediment elutriate tests in Megginnis Arm, found high concentrations of turbidity, dis- solved phosphorus, ammonia, nitrate, and organic nitrogen. High levels of oils and greases occurred at abandoned boat launching ramps. Class III standards were violated for pH, turbidity, alkalinity, zinc, iron, and especially lead in the elutriate tests. Concentrations of organic matter, nutrients, and heavy metals were considerably higher in the surface sed- iments relative to deeper sediment layers. Oils and greases were also high in the sediments of Megginnis Arm, especially in the central portion of the Arm. An artificial marsh system was constructed to filter the storm water runoff and to reduce the loading of suspended materials entering the lake at the southern, most urbanized end (Northwest Florida Water Management District, unpublished report). This control system was altered almost con- tinuously since its inception (Schmidt-Gengenbach, 1991). There was evidence that the artificial marsh had not been fully effective (Tuovila et. al., 1987; Alam, 1988). Despite various efforts to improve the water quality of the Megginnis drainage area, the condition of the lake continued to worsen with respect to various forms of hypereutrophication and levels of pollutants during the late 1980s (Wanielista, 1976; Tuovila et. al., 1987; Alam, 1988). Byrne (1980) carried out a study of the effects of petroleum hydrocarbon concentrations on Lake Jackson. The implications of the results are qualified by the relatively obsolete chemical analyses used by the principal investigator. However, Byrne (1980) found that, by 1978–1979, there were marked increases in petroleum hydrocarbon concentrations in Lake Jackson sediments. These increases were associated with the expansion of urbanized areas around the lake. The principal source of the petroleum hydrocarbons was storm water runoff from urban areas. Some 90% of the 4380 kg of total hydrocarbons transported to Lake Jackson during 1978–1979 were of petroleum origin. Total hydrocarbons were most concentrated in sediments of Megginnis Arm. The primary inputs of such products were from storm water runoff and base flow from the surrounding watershed, along with dust fall, rainfall, and the decomposition of aquatic and terrestrial plant matter. Asphalt, com- posed of multipolymers of aromatic rings linked by aliphatic and/or naphthenic chains, were a source due to bleeding of petroleum products adsorbed on the asphaltic surfaces. Temperature-driven dissolution of organic molecules (i.e., summer bleeding) followed by storm water incidents accounted for the movement of petrochemical products via oil impregnation into and released from the asphalt. Upon flushing with rainwater, layers of the film were solubilized into a continuous flow phase (Byrne, 1980). portation in the southern drainage basins of Lake Jackson in the early 1970s was associated with extensive erosion problems. Massive amounts of sediments washed down the rela- tively steep slopes of the Okeheepkee Road sub-basin, eventually ending up in southern Lake Jackson. Following the construction of a series of intensive commercial developments at the head of the Okeheepkee sub-basin during the mid-1980s, there were increased erosion problems. Again, sediments and degraded water washed through the Okeheepkee drainage into Lake Jackson. Against local opposition, a holding (i.e., collecting) pond was constructed by local officials to capture some of this runoff. Instead of improving the situation, the pond simply concentrated the polluted water and redistributed it into a series of surface and groundwater flows that led to the contamination of local residences. This situation continues to this day, with polluted water entering Lake Jackson during prolonged rainstorms. The Indian Mounds Creek system is another major tributary to the Megginnis Arm drainage in Lake Jackson (Figure 2.3). This creek was artificially redirected in recent times (1950s) (D. Benton, personal communication, 1993). Continuous observations of the Indian 1966_book.fmPage19Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC The construction of highway I-10 (see Figure 2.3) by the Florida Department of Trans- 20 Restoration of Aquatic Systems Creek system indicate that it has been severely affected by storm water runoff from roads (U.S. 27) and shopping malls at the headwaters of the creek. There is a series of hyper- eutrophicated ponds along the upper drainage; polluted runoff from these ponds even- tually ends up in Lake Jackson. In addition to storm water pollution, sewage spills have damaged the Indian Mounds system. and housing developments. Storm water from the mall drains through a series of ponds directly into Lake Hall. Until recently, the outlet for this pond was damaged, and storm water ran almost continuously into the lake from the mall area. Recently, to the east, Thomasville Road has undergone major expansion with runoff from the road running directly into eastern sections of Lake Hall. Over the past few years, a series of major developments have been established in the Ford’s Arm drainage basin that extend from Lake Hall westward over Meridian Road and into Lake Jackson. This development has been accompanied by increasing levels of flooding and entry of polluted water through Ford’s Arm into the lake. Over the past 15 years, there has been increased urban development in the western of Little Lake Jackson with vegetation and associated sediments. Accelerated aquatic plant growth contributes to the impairment of lake habitat, altered sediment quality, increased filling with excess (unassimilated) organic matter, and associated water quality deteriora- tion due to the decomposition of such matter (Livingston and Swanson, 1993). Adverse biological effects are the result of cumulative impacts of the eutrophication process that, through altered aquatic plant assemblages, leads to simplified food webs and reduced fisheries potential. With time, areas of western Lake Jackson, affected by runoff from lakeside urban development and runoff from Little Lake Jackson, have shown increasing signs of deterioration (as outlined above). The primary source of polluted urban water to Lake Jackson is Megginnis Arm (see Figure 2.3). By 1986–1989, municipal development in the southern sub-basins of the lake was accelerated. During this period, Hydrilla became dominant in receiving areas of eastern Lake Jackson. The Northwest Florida Water Management District completed a small holding pond for the Megginnis Arm basin. Despite efforts to improve water quality of the Megginnis drainage during the late 1980s, lake water quality continued to worsen (Wanielista, 1984; Tuovila et al., 1987; Alam, 1988; Livingston, 1988a). Polluted storm water continued to flow through Megginnis Arm during the 1990s whenever it rained. Today, Megginnis Arm Creek drains a major urbanized area with malls, shopping centers, gas stations, a major interstate highway (I-10), and high-density urban/residential develop- ments. Despite construction of an additional holding pond and a freshwater marsh system, the Megginnis Arm continues to be a major source of polluted urban storm water to southern Lake Jackson with massive runoff and nutrient loading to the lake after pro- longed rainfall conditions. 2.4.2 Long-Term Cycles of Rainfall and Storm Water Runoff The ecological condition of a given lake must be viewed within the context of long-term and rainfall is complex. The increased lake stages during 1994 reflected preceding rainfall peaks as noted above. Increased rainfall was often noted during the summer months. Peak rainfall occurred during a series of storms spring–summer 1994. This was followed by a drought during 1995 and early 1996. Rainfall peaks again occurred during the summer of 1996. This peak was followed by decreasing rainfall during the summer and fall of 1997. During 1998, there was a drought, which was reflected in reduced lake stages. By 1999, 1966_book.fmPage20Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC The headwaters of the Lake Hall drainage basin (see Figure 2.1) consist of malls, roads, sub-basins of Lake Jackson (see Figure 2.3). Currently, nutrient loading has led to the filling changes of rainfall and lake water levels (Figure 2.4). The relationship between lake stage Chapter 2: Cultural Eutrophication of North Florida Lakes 21 Figure 2.4 (a) Lake stage (m) and (b) rainfall (cm) in Lake Jackson from winter 1988 to fall 1998. Data provided by the Northwest Florida Water Management District. 26 27 28 29 30 88win 88spr 88smr 88fal 89win 89spr 89smr 89fal 90win 90spr 90smr 90fal 91win 91spr 91smr 91fal 92win 92spr 92smr 92fal 93win 93spr 93smr 93fal 94win 94spr 94smr 94fal 95win 95spr 95smr 95fal 96win 96spr 96smr 96fal 97win 97spr 97smr 97fal 98win 98spr 98smr 98fal year/season Jax stage (season/m) (a) meters 0 5 10 15 20 25 88win 88spr 88smr 88fal 89win 89spr 89smr 89fal 90win 90spr 90smr 90fal 91win 91spr 91smr 91fal 92win 92spr 92smr 92fal 93win 93spr 93smr 93fal 94win 94spr 94smr 94fal 95win 95spr 95smr 95fal 96win 96spr 96smr 96fal 97win 97spr 97smr 97fal 98win 98spr 98smr 98fal year/season (b) cm 1966_book.fmPage21Friday,June3,20059:20AM © 2006 by Taylor & Francis Group, LLC [...]... Cond-J0 8-9 7-s Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan µmhos/cm Cond-J 3-0 2- s Cond-J0 3-9 7-s Chl-J 8-0 2- s Chla-J0 8-9 7-s Month Month (a) (b) Surface Chlorophyll a Bottom D.O Chl-J 1-0 2- s Chl-J 8-0 2- s DO-J 8-0 2- b DO-J0 8-9 7-b 12 10 8 6 4 2 0 Chl-J 4-0 2- s Chl-MB 1-0 2- s 100 µg/L 75 50 25 Month Month (c) Oct Nov Dec Jan Jun Jul Aug Sep Feb Mar Apr May Nov Dec Jan Aug Sep Oct May Jun Jul 0 Feb Mar Apr mg/L DO-J 3-0 2- b... 1966_book.fm Page 25 Friday, June 3, 20 05 9 :20 AM Chapter 2: Cultural Eutrophication of North Florida Lakes 25 TN-J03 TN-J05 TN-J08 TN-J10 TN-J14 TN-J15 TN-J16 Poly (TN-J03) 10 gN/kg DW 1 0.1 96-fal 96-sum 96-spr 96-win 95-fal 95-sum 95-spr 95-win 94-fal 94-sum 94-spr 94-win 93-fal 93-sum 93-spr 93-win 9 2- fal 0.01 year/season (a) TP-J03 TP-J14 TP-J05 TP-J15 TP-J08 TP-J16 TP-J10 Poly (TP-J03) gP/kg DW 1 0.1 96-fal... 96-fal 96-sum 96-spr 96-win 95-fal 95-sum 95-spr 95-win 94-fal 94-sum 94-spr 94-win 93-fal 93-sum 93-spr 93-win 9 2- fal 0.01 year/season (b) Figure 2. 6 (A) Sediment total nitrogen (TN) and (B) total phosphorus (TP) in Lake Jackson from fall 19 92 to fall 1996 © 20 06 by Taylor & Francis Group, LLC 1966_book.fm Page 26 Friday, June 3, 20 05 9 :20 AM 26 Restoration of Aquatic Systems water runoff; water... L−1) © 20 06 by Taylor & Francis Group, LLC 88/ 02 88/05 88/08 88/11 89/ 02 89/05 89/08 89/11 90/ 02 91/09 91/ 12 92/ 03 92/ 06 92/ 09 92/ 12 93/03 93/06 93/09 93/ 12 94/03 94/06 94/09 94/ 12 95/03 95/06 95/09 95/ 12 96/03 96/06 96/09 96/ 12 97/03 97/06 97/09 97/ 12 98/03 98/06 98/09 98/ 12 mg/L 88/ 02 88/05 88/08 88/11 89/ 02 89/05 89/08 89/11 90/ 02 91/09 91/ 12 92/ 03 92/ 06 92/ 09 92/ 12 93/03 93/06 93/09 93/ 12 94/03... 1966_book.fm Page 23 Friday, June 3, 20 05 9 :20 AM Chapter 2: Cultural Eutrophication of North Florida Lakes Cond-sJ03 Cond-sJ05 Cond-sJ08 Cond-sJ16 23 Poly (Cond-sJ03) 150 µmhos/cm 120 90 60 30 88/ 02 88/05 88/08 88/11 89/ 02 89/05 89/08 89/11 90/ 02 91/09 91/ 12 92/ 03 92/ 06 92/ 09 92/ 12 93/03 93/06 93/09 93/ 12 94/03 94/06 94/09 94/ 12 95/03 95/06 95/09 95/ 12 96/03 96/06 96/09 96/ 12 97/03 97/06 97/09 97/ 12 98/03 98/06 98/09 98/ 12 0 year/month... seasons of the year (Figure 2. 14b and d) This finding was consistent © 20 06 by Taylor & Francis Group, LLC 1966_book.fm Page 39 Friday, June 3, 20 05 9 :20 AM Chapter 2: Cultural Eutrophication of North Florida Lakes 39 Surface Chlorophyll a Chl-J 3-0 2- s Chla-J0 3-9 7-s Surface Conductivity 125 100 µg/L 75 50 25 Dec Jan Oct Nov Aug Sep Jun Jul Apr May 0 Feb Mar 350 300 25 0 20 0 150 100 50 0 Cond-J 8-0 2- s Cond-J0 8-9 7-s... 94/03 94/06 94/09 94/ 12 95/03 95/06 95/09 95/ 12 96/03 96/06 96/09 96/ 12 97/03 97/06 97/09 97/ 12 98/03 98/06 98/09 98/ 12 mg/L 1966_book.fm Page 24 Friday, June 3, 20 05 9 :20 AM 24 Restoration of Aquatic Systems PO4-sJ03 Chla-sJ03 © 20 06 by Taylor & Francis Group, LLC PO4-sJ05 Chla-sJ05 PO4-sJ08 Chla-sJ08 year/month (d) PO4-sJ10 Chla-sJ10 PO4-sJ16 1 0.1 0.01 year/month (c) Chla-sJ16 1000 100 10 1 0.1... 98/09 98/ 12 0 year/month (a) NH3-sJ03 NH3-sJ05 NH3-sJ08 NH3-sJ10 NH3-sJ16 10 mg/L 1 0.1 88/ 02 88/05 88/08 88/11 89/ 02 89/05 89/08 89/11 90/ 02 91/09 91/ 12 92/ 03 92/ 06 92/ 09 92/ 12 93/03 93/06 93/09 93/ 12 94/03 94/06 94/09 94/ 12 95/03 95/06 95/09 95/ 12 96/03 96/06 96/09 96/ 12 97/03 97/06 97/09 97/ 12 98/03 98/06 98/09 98/ 12 0.01 year/month (b) Figure 2. 5 Water quality features of Lake Jackson taken monthly... 1966_book.fm Page 22 Friday, June 3, 20 05 9 :20 AM 22 Restoration of Aquatic Systems major parts of Lake Jackson disappeared into the sinkholes, leading to the drying out of most of the lake during the prolonged drought of 1998 20 01 2. 4.3 Water Quality Changes Station locations in Lake Jackson are given in Figure 2. 3 Long-term changes in the water chemistry of Lake Jackson are given in Figure 2. 5 Statistical... (Figure 2. 10) and was present throughout Lake Jackson during various times although the main peaks of this species occurred in the fall During peak dominance of Microcystis aeruginosa and A flos-aqua © 20 06 by Taylor & Francis Group, LLC 1966_book.fm Page 31 Friday, June 3, 20 05 9 :20 AM Chapter 2: Cultural Eutrophication of North Florida Lakes ANAPLA-J03 ANAPLA-J08 31 ANAPLA-J11 ANAPLA-J06 120 Anabaena . 1996. 0.01 0.1 1 10 9 2- fal 93-win 93-spr 93-sum 93-fal 94-win 94-spr 94-sum 94-fal 95-win 95-spr 95-sum 95-fal 96-win 96-spr 96-sum 96-fal year/season (a) TN-J03 TN-J05 TN-J08 TN-J10 TN-J14 TN-J15 TN-J16 Poly. (TN-J03) gN/kg DW 0.01 0.1 1 9 2- fal 93-win 93-spr 93-sum 93-fal 94-win 94-spr 94-sum 94-fal 95-win 95-spr 95-sum 95-fal 96-win 96-spr 96-sum 96-fal year/season TP-J03. DW 0.01 0.1 1 9 2- fal 93-win 93-spr 93-sum 93-fal 94-win 94-spr 94-sum 94-fal 95-win 95-spr 95-sum 95-fal 96-win 96-spr 96-sum 96-fal year/season TP-J03 TP-J05 TP-J08 TP-J10 TP-J14 TP-J15 TP-J16 Poly. (TP-J03) (b) gP/kg. LLC 24 Restoration of Aquatic Systems 0.01 0.1 1 88/ 02 88/05 88/08 88/11 89/ 02 89/05 89/08 89/11 90/ 02 91/09 91/ 12 92/ 03 92/ 06 92/ 09 92/ 12 93/03 93/06 93/09 93/ 12 94/03 94/06 94/09 94/ 12 95/03 95/06 95/09 95/ 12 96/03 96/06 96/09 96/ 12 97/03 97/06 97/09 97/ 12 98/03 98/06 98/09 98/ 12 year/month (c) PO4-sJ03