159 chapter 5 Nutrient Loading and the Perdido System 5.1 Phytoplankton Blooms in Coastal Systems Anthropogenous nutrient loading has resulted in increased incidence and severity of plankton blooms in coastal systems around the world (Hallegraeff et al., 2003). Between 1965 and 1976, the number of confirmed worldwide red tide outbreaks (raphidophytes, dinoflagellates) increased sevenfold concurrent with a twofold increase in nutrient loading (Hallegraeff, 1995; Hallegraeff et al., 1995). Bricker et al. (1999) stated that 44 estuaries in the conterminous United States suffer “high expressions of eutrophic conditions,” with an additional 40 estuaries having “moderate [eutrophic] conditions.” In the United States, adverse effects due to plankton blooms are most pronounced along the coasts of the Gulf of Mexico and the Middle Atlantic states. Bricker et al. (1999) projected that eutrophic conditions would worsen in 86 estuaries by the year 2020. Of the approximate number of marine phytoplankton species (5000), some 300 species are considered to occur at numbers high enough to discolor seawater (Sournia et al., 1991). Many algal specialists consider a bloom to be defined as a population density in excess of 1 × 10 6 cells L –1 although such numbers are not necessarily required for adverse impacts on other species (Hallegraeff et al., 2003). We used this criterion to identify ten bloom 2002). About 40 or 50 of the known bloom species produce toxins that can affect both natural marine populations of plants and animals as well as human beings (Hallegraeff et al., 1995). Anderson (1996) included in the concept of blooms the concentration(s) of one or more species that cause harm to other species or that cause accumulations of toxins in such a way as to cause harm to those who might eat the toxic species. These so-called harmful algal blooms (HABs) produce and release substances having direct and/or indi- rect effects on associated plant and animal populations. We have made quantitative assess- ments of the bloom species to identify those associated with adverse effects on animal populations and the food web structure in the Perdido Bay system (Livingston, 2000, 2002). Specific bloom species are responsible for severe damage to estuarine resources. Hetero- sigma akashiwo frequently causes heavy and extensive red tide events (Hara and Chihara, 1987) and has been associated with fish kills in New Zealand, Chile, and British Columbia (Chang et al., 1990). Imai et al. (1997) described the life-cycle and bloom dynamics of Chattonella , a genus with two known fish-killing species ( C. antiqua and C. marina ). The dinoflagellate Prorocentrum minimum is a toxic bloom species associated with postulated shellfish poisoning and fish kills. Nakazima (1965) indicated poisonous effects on shellfish 1966_book.fm Page 159 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC species in the Perdido system (Figure 5.1) over the 16-year study period (Livingston, 2000, 160 Restoration of Aquatic Systems feeding on Prorocentrum sp. Lassus and there are also reports that P. minimus caused mortalities in old oysters. Woelke (1961) found that this species caused oyster ( Ostrea iurida ) mortalities and cessation of feeding at high densities. The above bloom species have been found in concentrations greater than 1 × 10 6 cells L –1 in Perdido Bay. 5.2 Research in the Perdido River–Bay System A long-term (16 years of sampling by September 2004), interdisciplinary study has been carried out to determine the response of the Perdido drainage system (northeast Gulf of Mexico; Figure 5.1) to effluent loading from a pulp mill and other sources of nutrients that include a sewage treatment plant (STP) and agricultural/urban runoff (Livingston, 2000, 2002). The research effort is based on written, peer-reviewed protocols for all field analyses and specific biological methods have been certified through the Quality Assur- ance Section of the Florida Department of Environmental Protection (Comprehensive QAP #940128 and QAP #920101). These methods have also been published in peer-reviewed journals (Flemer et al., 1997; Livingston, 1975a, 1976a, 1980a, 1982a, 1984a,b, 1985a, 1987c, 1988b,c, 1992b, 1997a–f, 2004a,b; Livingston et al., 1974, 1976a,b, 1997, 1998a,b). All sampling for water quality, nutrient loading, phytoplankton, infaunal and epibenthic macroinvertebrates and fishes in the Perdido River and Bay system (Figure 5.1) has been carried out monthly to quarterly on a synoptic basis (i.e., all samples taken within one tidal cycle). River stations used for the determination of nutrient loading are shown Figure 5.1 Perdido drainage system, contributing rivers, and near-shore parts of the Gulf of Mexico with distributions of permanent sampling stations used in the long-term studies of the area. The Florida Geographic Data Library (FGDL) provided geographic data. 42B 42C 42A 42 46 45 43 44 40 37 37 31 18 09 25 29 22 21 23 26 SC1 SC2 48 47 WE N S GULF OF MEXICO PERDIDO BAY WOLF BAY 41 1966_book.fm Page 160 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC and laboratory operations, which are given in Appendix I. Water-quality methods and Chapter 5: Nutrient Loading and the Perdido System 161 in Figure 5.2. Loading to the upper bay from various sources included the following parameters: 1. Nitrogen nitrate and nitrite 2. Ammonia nitrogen 3. Organic nitrogen and organic phosphate a. Total organic nitrogen and total organic phosphate b. Dissolved organic nitrogen and dissolved organic phosphate c. Particulate organic nitrogen and particulate organic phosphate 4. Total nitrogen 5. Orthophosphate 6. Total dissolved phosphorus 7. Total phosphorus 8. Dissolved reactive silicate 9. Inorganic carbon 10. Organic carbon a. Dissolved organic carbon b. Particulate organic carbon c. Total organic carbon 11.Total carbon Figure 5.2 River stations used for sampling of chemical and biological factors and nutrient loading. The Florida Geographic Data Library (FGDL) provided geographic data. 1966_book.fm Page 161 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC Detailed protocols for the various field and laboratory operations are given in Appendix I. 162 Restoration of Aquatic Systems 5.3 History of Results Using a database that includes long-term, species-specific phytoplankton analyses, nutri- ent loading, water/sediment quality data, biological (infauna, invertebrate, fish) collec- tions, and food web determinations, we have been able to quantify the origin, succession, Analyses of the data have been published by Livingston (2000, 2002). 5.3.1 River Flow Trends River flow trends in the Perdido system over the study period are shown in Figure 5.3. There were three droughts during the study period 1988–2004: 1988, 1993–1994, and 1999–2002. The most recent dry period was considered the drought of the century, com- parable only to the drought of the mid-1950s (Livingston et al., 2003). Livingston (2002) noted that there were two basic components of Perdido River flow: (1) winter–early spring highs and (2) late summer–fall lows. Two-way ANOVAs, run by year and season using monthly averages within each season as replicates, indicated significant (P = 0.05) differ- ences between winter–early spring and late summer–fall flows. Aperiodic freshwater influxes to the bay due to storm activity accounted for occasional peak flows during most months of the year over the 16-year study period. Droughts were defined by continuous low summer flows and relatively flat river curves during winter–early spring flood peri- ods. Relatively heavy river flow events occurred during winter–spring 1990, over a pro- longed period from spring 1995 through winter 1996, during winter 1998, and during five Figure 5.3 Flow rates of Elevenmile Creek and the Perdido River system at monthly intervals from October 1988 to June 2004. 1 10 100 1988/10 1989/02 1989/06 1989/10 1990/02 1990/06 1990/10 1991/02 1991/06 1991/10 1992/02 1992/06 1992/10 1993/02 1993/06 1993/10 1994/02 1994/06 1994/10 1995/02 1995/06 1995/10 1996/02 1996/06 1996/10 1997/02 1997/06 1997/10 1998/02 1998/06 1998/10 1999/02 1999/06 1999/10 2000/02 2000/06 2000/10 2001/02 2001/06 2001/10 2002/02 2002/06 2002/10 2003/02 2003/06 2003/10 2004/02 2004/06 month 11 flow Perdido flow m 3 /sec 1966_book.fm Page 162 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC and impact of phytoplankton blooms on the Perdido Bay system (see Figures 5.1 and 5.2). Chapter 5: Nutrient Loading and the Perdido System 163 storm periods. A trend analysis of monthly river flows indicated that storm-related increases in river flows were most noticeable during 1995 and 1997–1998. River flows during drought periods were significantly (P = 0.05) different from those during the peak years of 1990 and 1995–1996. With the exception of the 1994 storm, most storm events occurred during summer low flows. 5.3.2 Nutrient Loading In Upper Perdido Bay during 1988–1991, there were no plankton blooms and areas asso- ciated with Elevenmile Creek had relatively high secondary production (Livingston, 1992b). Nutrients (orthophosphate, ammonia) released from a pulp mill on Elevenmile Creek were not associated with phytoplankton blooms. Phytoplankton productivity actu- ally stimulated secondary production: there were peaks of estuarine fish and invertebrate populations in areas surrounding the mouth of Elevenmile Creek. However, beginning in 1993–1994, increased nutrient discharges from the mill into upper Perdido Bay (Figure 5.4) were associated with a series of plankton blooms. These blooms followed patterns of increased orthophosphate and ammonia loading by the pulp mill from 1993 to 1999. The two primary sources of nutrient loading to upper Perdido Bay included the Perdido River system and Elevenmile Creek (Livingston, 2000, 2002, 2003). Loading of TN, TP, TON, nitrite/nitrate (NO 2 +NO 3 ), total carbon (TC), and silica (SiO 2 ) was domi- nated by the Perdido River (Livingston, 2002, 2003). This loading usually peaked in Figure 5.4 Nutrient loading (ammonia and orthophosphate) in Elevenmile Creek and the Perdido River system, monthly from October 1988 to June 2004. 10 100 1000 10000 1988/10 1989/02 1989/06 1989/10 1990/02 1990/06 1990/10 1991/02 1991/06 1991/10 1992/02 1992/06 1992/10 1993/02 1993/06 1993/10 1994/02 1994/06 1994/10 1995/02 1995/06 1995/10 1996/02 1996/06 1996/10 1997/02 1997/06 1997/10 1998/02 1998/06 1998/10 1999/02 1999/06 1999/10 2000/02 2000/06 2000/10 2001/02 2001/06 2001/10 2002/02 2002/06 2002/10 2003/02 2003/06 2003/10 2004/02 2004/06 year-month (a) 11MC-NH 3 Load BWStyxPerdido-NH 3 Load kg/day 1966_book.fm Page 163 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC 164 Restoration of Aquatic Systems winter–spring periods. Ammonia and orthophosphate loading was highest in Elevenmile from the creek peaked from February to April and July. Ammonia loading from Elevenmile Creek was relatively low during the early years of analysis. Ammonia loading from Elevenmile Creek to Perdido Bay was significantly higher during the period 1995–1999 than that of the preceding periods (Livingston, 2000, 2002). Ammonia loading rates less than these levels were comparable to those of Elevenmile Creek and the Perdido River system during the period of relatively low ammonia and orthophosphate loading (1989–1991). There was a progressive reduction of ammonia loading from 1999 to 2004, with occasional peaks in 2001, fall 2002, and summer 2003. Orthophosphate loading tended to be highest from the creek during October and July. Orthophosphate loading was generally low during the first few years of sampling, with occasional peaks in 1989 (Figure 5.4). There was an increase of such loading from 1992 to 1993, with relatively high orthophosphate loading from 1994 to 1997. These loadings were significantly higher than orthophosphate loading during the early years of sampling (Livingston, 2000, 2002). From fall 1997 to 1998, treatment of orthophosphate with alum by the mill reduced such loading to levels noted during the early sampling period, after which there was a general increase in 1999. With the exception of peaks during 2000, fall 2002, and summer 2003, there was a general decrease in orthophosphate loading from the mill from 1999 to 2004 to levels that approximated those during the first 3 years of sampling (1989–1991). FIGURE 5.4 (continued) 1 10 100 1000 1988/10 1989/02 1989/06 1989/10 1990/02 1990/06 1990/10 1991/02 1991/06 1991/10 1992/02 1992/06 1992/10 1993/02 1993/06 1993/10 1994/02 1994/06 1994/10 1995/02 1995/06 1995/10 1996/02 1996/06 1996/10 1997/02 1997/06 1997/10 1998/02 1998/06 1998/10 1999/02 1999/06 1999/10 2000/02 2000/06 2000/10 2001/02 2001/06 2001/10 2002/02 2002/06 2002/10 2003/02 2003/06 2003/10 2004/02 2004/06 year/month (b) 11MC-PO4 Load BWStyxPerdido-PO4 Load kg/day 1966_book.fm Page 164 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC Creek as a function of the contribution from the pulp mill (Figure 5.4). Ammonia loading Chapter 5: Nutrient Loading and the Perdido System 165 5.3.3 Nutrient Concentrations and Ratios Orthophosphate concentrations were usually highest at Station P23 at the mouth of Eleven- mile Creek during the early years of the study. From 1993 through the third quarter of 1997, there was a consistent pattern of high orthophosphate concentrations at the mouth of Elevenmile Creek. There was a precipitous decrease in this nutrient throughout the bay during late 1997–1998; this decrease was associated with reductions of mill orthophosphate discharges from August 1997 through March 1999 (Livingston, 2000, 2002). Orthophos- phate levels during late 1997–late 1998 resembled those during the period 1989–1990. This trend was followed by increased orthophosphate concentrations during the spring and summer of 1999, at which time the mill resumed relatively high loading of orthophosphate to Elevenmile Creek. By September 1999, the mill again reduced orthophosphate loading to the bay, and upper bay concentrations of this nutrient reflected this change. This trend continued through the 2004 sampling period. Ammonia concentrations in bay waters were relatively high during the 1989–1991 period (Livingston, 2000, 2002). There were periodic increases in ammonia during 1990 and 1991. By 1993, mean ammonia concentrations in the bay were somewhat lower; this pattern of reduced ammonia continued, with further decreases from late 1997 through early 1998. Increased ammonia concentrations were noted during the summer–fall months of 1998, with reduced ammonia during 1999. Low ammonia was associated with bloom activity in the bay (Livingston, 2000, 2002). Thus, higher ammonia loading from Eleven- mile Creek from 1995 to 1999 was accompanied by periodic reductions in ammonia concentrations in the upper bay due to bloom activity. Variables other than loading were involved in the trends of ammonia concentrations in the bay. The ratios of surface ammonia and orthophosphate entering the bay from Elevenmile (Livingston, 2000, 2002). One difference was the influence of droughts (especially the drought of 1999–2002) when the ammonia and orthophosphate ratios were proportionately higher than the absolute loading rates. The general declines from 1999 to 2003 were evident; concentration ratios were relatively low during the resumption of increased river flows from 2002 to 2003 and the reduced loading from the paper mill. These gradients, together with high nutrient loading rates and drought–flood cycles, tended to define the nature and extent of seasonal and interannual bloom successions. The drought from 1998 to 2002 had an important influence on these relationships (Livingston, 2002). By averaging differenced data for (orthophosphate + ammonia) loadings and concen- tration ratios, the data were standardized so that the combined effects of these two nutrients could be evaluated. These transformations were expressed as percent (%) ratio and loading differences from the mean. The long-term changes of such indices are shown decrease in this index from 1999 to 2003. Ratio differences were highest during 1995–1996 and fall 2002, and the differences from the loading trends reflected the effects of drought on such ratios. The decrease in such ratios over the past few years corresponded to reductions of mill loading of ammonia and orthophosphate. 5.3.4 Phytoplankton Trends: Bloom Distribution Livingston (2002) noted that river-dominated estuaries in the northeast Gulf of Mexico are highly productive due to factors such as nutrient enrichment from land runoff, the shallow nature of the receiving system, and energy supplements from wind, tidal currents, and thermohaline circulation. Processes that determine primary productivity (based largely on phytoplankton activity) and associated food webs in coastal areas vary widely 1966_book.fm Page 165 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC Creek (Station 22/23) followed the same general pattern as the loading (Figure 5.5) in Figure 5.6. Ratio differences of loading were highest from 1993 to 1999, with a general 166 Restoration of Aquatic Systems due to differences in nutrient loading, the physiography of the receiving area, and habitat features such as temperature, salinity, stratification characteristics, currents, light trans- mission, and sediment quality. Nutrient loading is fundamental to the growth of coastal phytoplankton (Livingston, 2000). Light availability is an important determinant of estu- arine and coastal phytoplankton communities (Philips et al., 2000). Biological processes (competition, predation) also influence phytoplankton production. Different combinations of the set variables thus determine the highly individual rates of primary production and food web responses that differentiate one system from another with resulting differences in population dynamics, community structure, and overall secondary production (Living- ston, 2000, 2002). The response of phytoplankton to nutrient loading in coastal systems has been well studied (Anderson and Garrison, 1997). Specific effects of nutrient loading on phytoplank- ton assemblages can be related to currents and salinity distribution (Squires and Sinnu, 1982), the physiography of contributing systems (Marshall, 1982a,b, 1984, 1988), and effects of human activities. Industrial wastes such as pulp mill effluents are known to affect phytoplankton (Reddy and Venkateswarlu, 1986). Resulting changes included increased domination by Cyanophycean types, along with the reduction of green algae. Sewage wastes have been associated with Oscillatoria spp., Rhopalodia gibberula, and Nitzschia pale . Blue-green algae ( Oscillatoria nigroviridis ) are often indicators of waters affected by sewage (Premula and Rao, 1977), although blue-green algae are also abundant in marine areas under natural conditions (Potts, 1980). A Prorocentrum micans bloom in a New Zealand estuary was coincident with increased nitrogen from upwelling (Chang, 1988). Figure 5.5 Ammonia and orthophosphate ratios at the mouth of Elevenmile Creek as it enters the bay system, taken monthly from October 1988 through June 2004. 0 15 30 45 60 1988/10 1989/02 1989/06 1989/10 1990/02 1990/06 1990/10 1991/02 1991/06 1991/10 1992/02 1992/06 1992/10 1993/02 1993/06 1993/10 1994/02 1994/06 1994/10 1995/02 1995/06 1995/10 1996/02 1996/06 1996/10 1997/02 1997/06 1997/10 1998/02 1998/06 1998/10 1999/02 1999/06 1999/10 2000/02 2000/06 2000/10 2001/02 2001/06 2001/10 2002/02 2002/06 2002/10 2003/02 2003/06 2003/10 2004/02 2004/06 year/month sNH 3 (22/23) sPO4 (22/23) 22/23 ratios 1966_book.fm Page 166 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC Chapter 5: Nutrient Loading and the Perdido System 167 Flemer et al. (1997) described results of nutrient limitation experiments conducted with water taken from Perdido Bay during 1991. Six experimental treatments were estab- lished in triplicate for each of three bay stations (P23, P31, and P40). Treatments included three control tanks, three P-enriched tanks at 10 µ M PO 4 -P above ambient, three N-enriched tanks at 50 µ M NH 3 -N above ambient, and three combined NH 3 +PO 4 (referred to as N+P) above ambient, as described for single additions. Primary P limitation occurred mostly during cooler months at upper (tidal brackish) and mid-bay (lower mesohaline) stations. Primary N limitation occurred mostly during warmer months (late summer–fall) in mid-bay areas and infrequently at upper and lower bay stations (upper mesohaline). Apparent N+P co-limitation occurred throughout the year, with peaks during spring and fall in the upper bay. Winter and summer–fall peaks were noted in mid-bay areas, with summer peaks in the lower bay. Primary orthophosphate limitation was associated with high dissolved inorganic nitrogen (DIN); DIN/dissolved inorganic phosphorus (DIP) ratios ranged from 20 to 200. Conversely, primary N and N+P co-limitation were associated with decreasing DIN/DIP ratios. Phytoplankton assemblages were not strongly nutrient limited, but, given a nutrient increase, these groups responded differentially to nitrogen and phosphorus, both season- ally and along the longitudinal salinity gradient. The combination of phosphorus and nitrogen was usually more stimulatory to phytoplankton growth in Perdido Bay than either of these nutrients alone. Overall, nutrient limitation in Perdido Bay was seasonal, with phosphorus limitation during cold months and nitrogen and/or (nitrogen + phos- phorus) limitation during warm months. Figure 5.6 P+N percentage ratio differences (and 3-month moving average) in Elevenmile Creek, taken monthly-to-quarterly from October 1988 through September 2003. −200 −100 0 100 200 300 400 500 1988/10 1989/02 1989/06 1989/10 1990/02 1990/06 1990/10 1991/02 1991/06 1991/10 1992/02 1992/06 1992/10 1993/02 1993/06 1993/10 1994/02 1994/06 1994/10 1995/02 1995/06 1995/10 1996/02 1996/06 1996/10 1997/02 1997/06 1997/10 1998/02 1998/06 1998/10 1999/02 1999/06 1999/10 2000/02 2000/06 2000/10 2001/02 2001/06 2001/10 2002/02 2002/06 2002/10 2003/02 2003/06 2003/10 2004/02 2004/06 year/month P+N % ratio diff P+N % load diff % Ratio differences 1966_book.fm Page 167 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC 168 Restoration of Aquatic Systems During early years of analysis (1988–1991), orthophosphate and ammonia loading from the pulp mill enhanced secondary production in the immediate receiving area of the upper estuary (Livingston, 2000, 2002). Plankton blooms were not present during this period. The chrysophytes and, to a lesser degree, the chlorophytes tended to be abundant and were associated with a balanced food web and relatively high secondary production in the upper bay. During the winter–spring drought in 1993–1994, the pulp mill increased orthophosphate loading to the bay. The combination of drought conditions and increased orthophosphate loading was associated with phytoplankton blooms dominated by diatom species . There was an orderly seasonal succession of these bloom species in the bay. Continued high orthophosphate loading over the next 3 years led to increases in phy- toplankton bloom frequency and intensity throughout the bay. From 1996 through 1998, there was increased ammonia loading to the upper bay by the pulp mill. Plankton response included a pattern of the individual bloom species that was attributed to seasonal differ- ences in nutrient requirements of the bloom species. Interannual qualitative and quanti- tative phytoplankton dominance shifts occurred from 1993 through 1999, whereby larger- celled raphidophyte and dinoflagellate species replaced diatom species that had been predominant during the initial blooms. Increased dominance of bloom species was usually accompanied by reductions in phytoplankton species richness. There was a long-term increase in plankton numbers and biomass during the years of increased nutrient loading. From late summer 1997 through spring 1999, the pulp mill reduced its orthophosphate loading and there were concurrent reductions of the high relative dominance of bloom species, especially during winter–spring periods (Livingston, 2000, 2002). There was a partial recovery of the phytoplankton associations during the period of low orthophos- phate loading to upper Perdido Bay. However, by spring 1999, the mill again resumed high orthophosphate loading to the bay. This loading was accompanied by bay-wide spring and early summer blooms, increased dominance of bloom species, and associated reductions in phytoplankton species richness. The postulated effects of increased ortho- phosphate and ammonia loading were usually correlated with general sequences of bloom species and associated changes in the phytoplankton community structure, which were consistent with observed natural history characteristics of the diatoms, raphidophytes, and dinoflagellates that comprised the bloom types. There were distinct concentration gradients of the orthophosphate and ammonia as water from Elevenmile Creek entered the bay; such areas were noted as primary sites of bloom origin. The concentration gra- dients appeared to provide the spark that ignited at least some of the plankton blooms. The spatial–temporal distribution of the plankton blooms in the Perdido system is of the bloom species in Perdido Bay. In the upper bay, Prorocentrum minimum and Lepto- cylindrus danicus were restricted to winter peaks, whereas the raphidophyte blooms ( Heterosigma akashiwo and Chattonella subsalsa ) occurred during warm months of the year. The diatoms Cyclotella choctawhatcheeana and Miraltia throndsenii bloomed mainly during spring months, whereas Synedropsis sp. bloomed during the summer. The raphidophyte and blue-green algae blooms occurred later in the interannual bloom succession, and it is possible that H. akashiwo displaced C. choctawhatcheeana when it reached bloom numbers. Seasonal changes of monthly averages of nutrient loading in the Perdido system indicate that the highest ammonia loading in Elevenmile Creek occurred during early summer months (June–July) (Livingston, 2002). Ammonia loading from the Perdido River followed the same seasonal pattern, peaking from May through July. Orthophosphate loading in the creek was highest during summer months. In the Perdido River, such loading again followed a similar pattern, peaking in May. Relative abundance (% total numbers) of diatoms occurred during late winter–spring months. There was no statistical 1966_book.fm Page 168 Friday, June 3, 2005 9:20 AM © 2006 by Taylor & Francis Group, LLC shown in Table 5.1. There was a distinct species-specific pattern to the seasonal occurrence [...]... 9:20 AM 176 Restoration of Aquatic Systems TN-18 TN-29 TN-22 TN-31 TN-23 TN-33 TN- 25 TN-37 TN-26 TN-40 0.7 0.6 0 .5 mg/g 0.4 0.3 0.2 0.1 0 88 91 94 97 99 02 05 02 05 month/year (a) TP-18 TP-29 TP-22 TP-31 TP-23 TP-33 TP- 25 TP-37 TP-26 TP-40 0.6 0 .5 mg/g 0.4 0.3 0.2 0.1 0 88 91 94 97 99 month/year (b) Figure 5. 10 Sediment analyses of (A) total organic nitrogen (TON) and (B) total phosphorus (TP) during... 0. 45 29 31 37 40 16.12 11.60 4.23 2 .55 30.98 24.87 17.28 11.97 25. 61 5. 28 0.09 0.00 0.78 0.20 0.03 0.04 19.09 12.44 3.06 2 .53 9.33 3 .53 1.33 0. 65 6.84 3.36 15. 97 4.60 3.74 4.22 7.81 7.28 7.72 0.30 1.33 2.14 1.61 2.26 5. 69 5. 80 0.00 0.00 0.00 0.00 1.28 0. 65 7. 35 0.12 1.09 2.26 3.73 4.08 2.04 0.93 0 .56 0 .56 0.89 1.32 1.99 1.87 1.03 0.88 1.33 0.92 0.37 0.67 2.04 2.21 0.27 0.66 1.61 1 .50 0.76 0.73 0. 65. .. recovery of this group of organisms relative to this index taken during periods of no blooms (1988–2002) Prorocentrum continued to decrease during the last 2 years of sampling, whereas Heterosigma showed marked increases during fall 2002 and summer 2003 © 2006 by Taylor & Francis Group, LLC 1966_book.fm Page 176 Friday, June 3, 20 05 9:20 AM 176 Restoration of Aquatic Systems TN-18 TN-29 TN-22 TN-31 TN-23... 0. 65 0 .57 0.00 0.34 0.61 2.13 0.22 0. 35 1.10 1.07 0.01 0.00 0.00 0.01 0. 25 0.37 0 .56 0.68 0.17 0.23 0 .55 0 .59 0.23 0.28 0.42 0.41 0.00 0.00 0.00 0.00 0.08 0. 15 0.09 0.43 0.09 0. 05 0.03 0.03 0.10 0.14 0.07 0.00 223 1,804 1,236 1,883 127 120 160 119 2.02 2.02 1.99 1.80 0.42 0.42 0.39 0.38 0.32 0.01 0.00 848 177 2.19 0.42 TOTAL 288 .59 173.44 128 .52 104.17 94. 25 50.86 42.37 34.82 22.23 20.11 17. 35 14.89... 16.62 2.71 0 .51 1.83 0.23 0.86 0.29 0.87 0.64 0.06 0.06 0.03 0.24 0.16 0.11 1.62 45. 52 26 .58 16.62 0.46 16.97 10.49 4.24 4.22 0.06 1.86 0.00 1 .58 1.00 2.07 0. 95 1.01 0.17 0 .56 0.71 0.09 0.19 0.00 0.30 0.19 0.26 0.00 78.11 37.92 16.47 0.60 24.33 13.46 5. 60 5. 49 9.84 2. 15 0.00 1.13 0.92 2.38 1.00 1.00 0.21 0.48 1.66 0.20 0.27 0.01 0.19 0.20 0.27 0.00 0. 05 0.14 0.18 3,676 237 1.40 0.26 0. 15 0. 05 0.22 163... bay south of Ono Island (Station P48) These data indicate water quality problems in areas receiving runoff from urban areas © 2006 by Taylor & Francis Group, LLC 1966_book.fm Page 180 Friday, June 3, 20 05 9:20 AM 180 Restoration of Aquatic Systems 4–6 6–8 8–10 10–12 12–14 1988 – 1991 1997 – 1999 1999 – 2001 16–18 1993 – 19 95 19 95 – 1997 14–16 2001 – 2003 Figure 5. 14 Total number of species of infaunal... clear gradient from the mouth of Elevenmile Creek to the depositional areas of the upper and lower bay However, after reductions of ammonia loading by the mill, the fall 2001 analysis indicated a shift in the location of upper bay © 2006 by Taylor & Francis Group, LLC 1966_book.fm Page 174 Friday, June 3, 20 05 9:20 AM 174 Restoration of Aquatic Systems 20 number of blooms 15 10 0 1988/10 1989/02 1989/06... June 3, 20 05 9:20 AM 186 Restoration of Aquatic Systems … ‘Any kind of development does have an impact, but the lower part of this bay is in far better shape than the upper part of the bay.’ Jackie Lane…also criticized Livingston’s conclusions Like Morrill, she had not seen a copy of his report.” —Associated Press, August 8, 1992 HEALTH OF PERDIDO BAY STILL AT ISSUE: “Dr Ishphording (University of South... the Perdido System Nutrient Loading Chapter 5: Table 5. 3 Summary of the Status of the Perdido Bay System by Fall 2003 1966_book.fm Page 192 Friday, June 3, 20 05 9:20 AM 192 Restoration of Aquatic Systems 2003), and (3) we discussed our findings with personnel from the ECUA The reporter informed me that he was anxious to do a story on the sewage issue Under the Freedom of Information Act, he obtained the... claims of various “environmentalists.” 5. 4.2 Cumulative Impacts of Development on Perdido Bay Following the prolonged drought of 1999–2002, there was a series of major rain events in the Perdido drainage basin These events in the fall of 2002 and summer of 2003 were associated with major changes in the ecological processes of the Perdido system These changes were reviewed within the context of long-term . 2003. 0 0.1 0.2 0.3 0.4 0 .5 0.6 0.7 88 91 94 97 99 02 05 month/year (a) TN-18 TN-22 TN-23 TN- 25 TN-26 TN-29 TN-31 TN-33 TN-37 TN-40 mg/g 0 0.1 0.2 0.3 0.4 0 .5 0.6 88 91 94 97 99 02 05 month/year (b) TP-18 TP-22 TP-23. 05 month/year (b) TP-18 TP-22 TP-23 TP- 25 TP-26 TP-29 TP-31 TP-33 TP-37 TP-40 mg/g 1966_book.fm Page 176 Friday, June 3, 20 05 9:20 AM © 2006 by Taylor & Francis Group, LLC Chapter 5: Nutrient Loading and. 2004. 10 100 1000 10000 1988/10 1989/02 1989/06 1989/10 1990/02 1990/06 1990/10 1991/02 1991/06 1991/10 1992/02 1992/06 1992/10 1993/02 1993/06 1993/10 1994/02 1994/06 1994/10 19 95/ 02 19 95/ 06 19 95/ 10 1996/02 1996/06 1996/10 1997/02 1997/06 1997/10 1998/02 1998/06 1998/10 1999/02 1999/06 1999/10 2000/02 2000/06 2000/10 2001/02 2001/06 2001/10 2002/02 2002/06 2002/10 2003/02 2003/06 2003/10 2004/02 2004/06 year-month (a) 11MC-NH 3 Load BWStyxPerdido-NH 3 Load kg/day 1966_book.fm Page 163 Friday, June 3, 20 05 9:20 AM © 2006 by Taylor & Francis Group, LLC 164 Restoration of Aquatic Systems