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Presentation Abstracts
Title: FerryMon: Ferry-based assessment of human and climatically-driven ecological change in the Pamlico Sound Estuarine system, NC
Author:
Hans W. Paerl
University of North Carolina at Chapel Hill, Institute of Marine Sciences, Morehead City, NC 28557
Email: hpaerl@email.unc.edu.
Lab website: www.unc.edu/ims/paerllab
Abstract: Nutrient over-enrichment is a chief cause of eutrophication, harmful algal blooms, hypoxia and habitat loss in estuarine and coastal waters worldwide. In North Carolina's Neuse River Estuary (NRE)-Pamlico Sound (PS) system, nitrogen (N)-driven eutrophication, water quality and habitat decline have prompted the State and US EPA to mandate N load reductions, including a total maximum daily allowable N load (TMDL). Chlorophyll a (chl-a), the indicator of algal biomass, is the measure for the efficacy of N reductions, with "acceptable" values being <40 g chl-a L-1. However, algal blooms are patchy in time and space, making exceedances of 40 g L-1 difficult to track and quantify. The NC ferry-based water quality monitoring program, FerryMon (www.ferrymon.org) is ideally suited to provide continuous, space-time intensive, accurate measurements of chl-a and other water quality criteria (temperature, salinity, dissolved oxygen, pH, turbidity) at time scales relevant to adaptive management of the TMDL. Complimenting FerryMon are automated vertical profilers (AVPs), located in segments of the NRE-PS experiencing nutrient impairment. They produce chl-a and other water quality indicator depth profiles with very high time and vertical resolution. Data from the sensors are transmitted by cell phone or Internet to the laboratory, where they are processed and distributed via the website and Internet to State and federal (EPA, NOAA, USGS) water quality agencies, schools, NGOs and the public. In 2007, In-line spectral fluorometers (Algae Online Analyzers (AOAs)) are being installed on the ferries. The AOAs will provide early, rapid detection and quantification of algal blooms. They will enhance spatial characterization of trends in water quality conditions over a range of relevant physical, chemical and biological time scales (minutes to months and beyond). This enhanced capability is timely, given a protracted period of increased tropical storm and hurricane activity that is impacting estuarine and coastal water quality in unpredictable yet important ways. These improvements facilitate calibration, and interpretation of remotely sensed indicators of water quality (photopigments, turbidity) and modeling, enabling investigators to scale up to the ecosystem-level. Data management and communication links allow FerryMon to integrate with other observational programs, including CUAHSI-WATERS, Coastal GOOS, SEACOOS, and when operational, NEON. The FerryMon website is oriented to provide educational and outreach capabilities. FerryMon's approach and technology are readily transferable to other estuarine, large lake and coastal ecosystems served by ferries and other "ships of opportunity".
Title: Metro Gets the P Out: Early Responses of Onondaga Lake to Improvements in Wastewater Treatment
Authors:
David A. Matthews and Steven W. Effler
Upstate Freshwater Institute, Syracuse, NY
Abstract: Reductions in nutrient loading to aquatic ecosystems are widely sought to ameliorate symptoms of cultural eutrophication, including high levels of phytoplankton biomass, blooms of nuisance cyanobacteria, low transparency, and dissolved oxygen depletion. Despite advances in the understanding of lake ecosystems in recent decades there remains considerable uncertainty in predicting the response of individual lakes to rehabilitation measures. A wide range of responses have been observed in lakes where major reductions in nutrient loading have been achieved. Water quality improvements have often been substantially delayed or modest relative to expectations. Responses of culturally eutrophic Onondaga Lake to reductions in phosphorus (P) loading from a contributing municipal wastewater treatment facility (Metro) are documented through an assessment of changes in common metrics of trophic state. Total P concentrations in the Metro effluent (TPMetro) decreased nearly 100-fold over the 1970 to 2007 interval, including a 4.5-fold reduction in 2006. The contribution of Metro to the total effective P load of the lake decreased from ~80% in 2000 to ~55% in 2007. Interannual differences in TPMetro explained 83% of the observed variability in summer average TP concentrations in the epilimnion (TPepi) during the 1986 to 2007 interval. The strong and rapid response of TPepi to changes in TPMetro is attributed to the extraordinary P load from Metro and the high flushing rate of the lake (~ 4 times/yr). Summer average chlorophyll-a concentrations in the epilimnion (Chlepi) decreased from 217 µg L-1 during 1989-2001 to 132 ug L-1 during 2002-2007, and major phytoplankton blooms (Chl>40 µg L-1) have not occurred since 2001. Corresponding increases in summer average Secchi disc transparency did not occur because of the loss of Daphnia in 2003, apparently due to predation by alewife, Alosa pseudoharengus, an efficient pelagic planktivore. TPMetro explained a large fraction of the interannual variations observed in the downward flux of volatile suspended solids to the hypolimnion (DFVSS; 70%) and the areal hypolimnetic oxygen deficit (AHOD; 72%). Large decreases in TPepi, Chlepi, DFVSS, and AHOD occurred from 2006 to 2007 despite a modest increase in TPMetro from 0.099 mg L-1 in 2006 to 0.12 mg L-1 in 2007. Improvements in these features of water quality from 2006 to 2007 are attributed to lower tributary flows, a decrease in internal P loading, and lower hypolimnetic temperatures. Further systematic improvements in TPepi, Chlepi, and DFVSS are not expected as a result of the most recent reductions in TPMetro. Modest decreases in AHOD may occur as the organic carbon content of the sediments approaches a new steady state consistent with lower DFVSS. Substantial year-to-year variations in metrics of trophic state should be expected as a result of variations in tributary flow, hypolimnetic temperatures, and food web structure. However, further decreases in TPMetro are expected to result in proportional decreases in TPepi and other common metrics of trophic state.
Title: Resolution of Spatial Patterns of Water Quality Parameters with Rapid Profiling Instrumentation
Authors:
Anthony R. Prestigiacomo, Steven W. Effler, Adam J.P. Effler, and Julia Braunmueller
Upstate Freshwater Institute, Syracuse, NY
Abstract: Three-dimensional patterns of an array of water quality metrics, including temperature, specific conductance, turbidity (or surrogates), chlorophyll a, and nitrate (NO3-), are resolved in Onondaga Lake based on measurements at multiple sites ("gridding") with rapid profiling instrumentation. Gridding was conducted in 2005, 2006, and 2007; the greatest temporal (weekly, n= 34) and spatial (36 sites) coverage was in 2007. Conspicuous three-dimensional patterns, with a variety of temporal features, are documented for each of the above metrics. Multiple effects of inflow buoyancy relative to the lake are depicted, including: (1) the plunging of saline Onondaga Creek and longitudinal expansion of the corresponding interflow pattern through summer, (2) variations of the depth of entry of the NO3- - enriched Metro discharge, from an overflow (usually) to an interflow, and (3) late summer entry of dilute Seneca River water into the northern end of the lake as an overflow. Patterns associated with mixing and transport processes are documented, including the effects of: (1) a seiche, and coupled vertical mixing, from a wind event, (2) transport of Onondaga Creek turbidity along the eastern shoreline following a runoff event, and (3) incomplete mixing between the north and south basins in fall 2007. Microbial processes also imparted spatial structure that included hypolimnetic depletion of NO3- (denitrification decomposition pathway) and horizontal differences in chlorophyll a, commonly described as phytoplankton patchiness. Resolution of the reported patterns is valuable in depicting the operation of important limnological processes for this lake, and in providing context for design of future monitoring programs and critical review of long-term single site data sets.
Title: Changes in Water Clarity in Onondaga Lake, Analysis of a 40-year Record
Authors:
Steven W. Effler, Rakesh Gelda, Amy Kolb, MaryGail Perkins, and Feng Peng
Upstate Freshwater Institute, Syracuse, NY
Abstract: A retrospective analysis of long-term data sets of Secchi disc depth (SD, 40 years), the diffuse light attenuation coefficient for downwelling irradiance for photosynthetically available radiation (kd(PAR), 23 years), and chlorophyll a ([Chl], 28 years), is presented for culturally eutrophic and industrially polluted Onondaga Lake, New York. The effects of changes in multiple drivers are resolved in the record, including salinity decreases from closure of an industry, changes in the grazing of exotic and native Daphnia, long-term variations in populations of planktivorous fish, runoff events, and progressive decreases in phosphorus (P) loading. Four intervals, or regimes, are identified for the record that had unifying features with respect to drivers and SD observations. The most dramatic changes in clarity conditions were the abrupt transition to annual occurrences of a clear-water-phase (CWP) for 16 years, following a coupled decrease in salinity and return of native Daphnia, and the subsequent loss of the CWP (for 5 years) from the loss of these cladocerans. The CWP was characterized by coincident dramatic increases in SD (annual maxima 4.55 m) and decreases in [Chl] and high concentrations of Daphnia. The benefits of P management were most clearly manifested by a 3-fold decrease in average [Chl] and a 2-fold increase in SD between two of the regimes, separated by 25 years, which lacked CWPs. A probabilistic mechanistic model for SD and kd(PAR), that represents the effects of multiple constituents on the regulating processes of absorption and scattering, is developed, tested for the long-term record, and applied to partition the scattering coefficient (b) according to contributions of phytoplankton and tripton (bNAP). Good model performance is demonstrated through: (1) closure of estimates of b with independent measurements, (2) consistencies of bNAP predictions with independent estimates based on an individual particle analysis technique, and the timing of runoff events, and (3) closure of predictions of kd(PAR) with observations. Nomographs are formed with the model that represent the dependence of SD and kd(PAR) on phytoplankton, [Chl], and inorganic tripton (bNAP) levels, that can be used to predict responses of these optical metrics to changes in the levels of these attenuating constituents. Inorganic tripton in the size range 1 to 10 µm, has played a critical role in influencing important features of the lake's optical regime by: (1) contributing importantly to b throughout the record (30 to 40%, on average), (2) regulating optical signatures from runoff and CWP events, and (3) limiting increases in SD that can be achieved from future decreases in phytoplankton biomass.
Title: Halite Brine in the Onondaga Trough near Syracuse, New York: Characterization and Simulation of Variable-Density Flow
Authors:
Dick Yager, Niel Plummer, Bill Kappel
United States Geological Survey
Abstract: Halite brine (saturation ranging from 45 to 80 percent) lies within glacial sediments that fill the Onondaga Trough, a bedrock valley deepened by Pleistocene glaciation near Syracuse New York State, USA. The most concentrated brine occupies the northern end of the trough, about 10 km downgradient of the northern limit of halite beds in the Silurian Salina Group, the assumed source of salt. The chemical composition of the brine and its radiocarbon age suggest that the brine originally formed about 16,700 years ago through dissolution of halite by glacial melt water and later mixed with saline bedrock water. Two hypotheses regarding the formation of the brine pool were tested through variable-density flow simulations using SEAWAT. Simulation results supported the first hypothesis that the brine pool was derived from a source in the glacial sediments and then migrated to its current position, where it has persisted for over 16,000 years. A second hypothesis that the brine pool formed through steady accumulation of brine from upward flow of a source in the underlying bedrock was not supported by simulation results, because the simulated age distribution was much younger than the age estimated from geochemical modeling.
Title: A Retrospective Analysis of Solids Deposition in Onondaga Lake, 1980-2007
Authors:
Craig Hurteau, David A. Matthews, and Steven W. Effler
Upstate Freshwater Institute, Syracuse, NY
Abstract: Long-term and seasonal temporal patterns in the deposition of volatile (VSS) and fixed suspended solids (FSS) are documented for eutrophic Ca2-rich Onondaga Lake, NY for a 28 year interval, 1980 to 2007. Weekly collections were made from sediment traps deployed below the thermocline from mid-May to mid-September in the deepest area of the lake (~20m). Following closure of a soda ash facility in 1986 that contributed significant amounts of ionic waste to the lake, the downward flux of VSS (DFVSS) decreased 43% from 4.2 to 2.4 g/m2/d and DFFSS decreased 35% from 15.2 to 9.9 g/m2/d. From 1987 to 2007 the downward flux of total suspended solids (DFTSS) averaged 11.3 g/m2/d, a high value compared to other lakes, and did not exhibit any significant long-term trends. DFFSS accounted for 80% to 85% of DFTSS, and deposition of CaCO3 accounted for 75% of DFFSS. DFVSS decreased 25% from 1988 to 2006 and an additional 25% from 2006 to 2007. Weekly variations in the DFVSS were generally correlated with chlorophyll levels in the upper waters and maximum values were observed during major phytoplankton blooms. Seasonal minimas of DFVSS and DFFSS occurred during clear water phases, which were observed annually from 1987 to 2002. These clear water events were caused by intense grazing of phytoplankton and probably inorganic particles by Daphnia. No significant relationships were found between DFFSS and the flow rate of a major tributary (Onondaga Creek) at time scales ranging from weekly to annual. The event-like character in the DFFSS is attributed to variations in CaCO3 precipitation, probably driven by variations in temperature, pH, and the availability of nucleation sites. Because in-lake processes account for 85% of DFTSS, changes in primary production and lake chemistry could have significant effects on the burial of contaminants and microbial metabolism in the sediments.
Title: Metro's Impact on Nitrogen Levels in Onondaga Lake, a 36-Year Record
Authors:
Steven W. Effler, Susan M. O'Donnell, Anthony R. Prestigiacomo, David M. O'Donnell, Rakesh Gelda and David A. Matthews
Upstate Freshwater Institute, Syracuse, NY
Abstract: A retrospective analysis of long-term trends in loading of nitrogen (N) forms from the Metropolitan Syracuse Wastewater Treatment Plant (Metro), concentrations of these forms in the receiving urban lake (Onondaga Lake, NY), and related water quality implications for the lake, is presented for the 1972-2007 period. The history of the evolution of treatment and discharge at Metro, as it affected loading, is reviewed and forms the basis for identification of five regimes during which unifying loading and in-lake conditions prevailed. The effects of upgrades in treatment at Metro, from primary (until 1978) to advanced treatment (starting in 2004), have been complicated by industrial waste inputs. Contemporary N loading from Metro is ~ 35% lower than the peak levels that prevailed from the late 1980s to late 1990s, but the areal rate remains extraordinarily high (~ 97g m-2 y-1), representing ~75% of the overall N load to the lake. Implementation of year-round nitrification treatment has resulted in the transformation of the composition of the N load from Metro from ammonia (T-NH3) to nitrate (NO3-) dominance. Extraordinarily high N concentrations have prevailed in the upper waters of the lake throughout the record; averages of total N from 2.6 to 4.3 mg L-1 for the five regimes are reported. Total N levels and partitioning amongst the forms in the lake have generally tracked the loading conditions of the five regimes. The effects of Metro loading on seasonal in-lake patterns are demonstrated to be modified by both hydrologic inputs from tributaries and the in-lake operation of biochemical processes. Resolution of these effects is supported by application of a dynamic mass balance analysis, which assumes conservative behavior. Severe water quality problems, that prevailed over most of the record, associated with the maintenance of high concentrations of forms of N are documented, including: (1) augmentation of dissolved oxygen depletion during fall mixing from nitrification events, enabled by high T-NH3 levels, (2) violations of ammonia toxicity standards, and (3) violations of nitrite toxicity standards. These problems have been either greatly ameliorated or eliminated by the most recent upgrades in treatment at Metro. Prevailing conditions are considered in a management context, including: (1) the likelihood of exceedences of toxicity standards in the future, and (2) the potential role of elevated nitrate levels in preventing mobilization of methyl mercury from the lake's sediments.
Title: Long-term Changes in Mercury in Biota of a Recovering Eutrophic and Mercury Contaminated Lake
Authors:
Svetoslava Todorova, Charles Driscoll, Oliver Fernandez
Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY
David A. Matthews, Steven Effler, and Michael E. Spada
Upstate Freshwater Institute, Syracuse, NY
Ankit Bhatia
Department of Chemistry, Princeton University, NJ
Abstract: Industrial inputs of ionic mercury (Hg2+) have resulted in an extended period of contamination in Onondaga Lake, NY. Sediment core and sediment trap data indicate a 90% reduction in Hg loading to the lake since the 1970s, associated with reductions in Hg discharge and ultimately closure of the chlor-alkali facility. Fish tissue data (NYSDEC) for the 1970-2006 period indicates continuously elevated Hg concentrations in several fish species. Fishing advisories on the lake have shifted from a ban in 1970, to being opened for fishing with no consumption in 1986, to recent advisories of no consumption for certain fish issued between 1993 and 2007 because of the high Hg content. Elevated concentrations of total Hg (THg) and methyl Hg (MeHg) have been measured historically in the water column of the lake. Methyl Hg is the form of Hg that bioaccumulates in the aquatic food chain and has been shown to affect the behavior of piscivorous birds, wildlife, and humans. The results of a three-year monitoring program (2005-2007) of the water column of the lake depict progressive decreases in hypolimnetic MeHg concentrations. The MeHg levels measured during the 2007 sampling season were the lowest of the record. The observed decreases in MeHg are linked to recent improvements in municipal wastewater treatment and associated increases in nitrate loading to the lake and decreases in primary production. Long-term temporal changes in the Hg content of smallmouth bass (SMB) and archived zooplankton assemblages (results of this study) in Onondaga Lake are also reviewed. Three periods were designated for this analysis - prior to closure of the industrial facility (1970-1986/88), post closure (1986/88-2003), and the period of recent improvements in features of water quality related to upgraded municipal wastewater treatment (2003-2007). The Hg content in SMB has exceeded the EPA threshold level of 0.3 ppm throughout the three periods; concentrations have been 1.5 to 2 times higher than concentrations in SMB in other NYS water bodies. The long-term trend in the SMB Hg content appears to track that of THg concentrations in zooplankton for the first two of the three periods. A substantial decline in zooplankton Hg levels was observed for the third period, an interval in which a marked increase in fish Hg concentrations occurred. The reason for this disparity between Hg levels in zooplankton and fish is not clear but may be due to a shift in the food chain in Onondaga Lake in recent years. Preliminary results indicate that MeHg concentrations in zooplankton are between 3 and 7% of THg concentrations; these values are low compared to most reported in the literature, but comparable to what has been reported in other contaminated lake systems. The potential interplay between changes in Hg speciation, primary production, the food web of the lake, and other factors are considered and discussed.
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