Bay Of Quinte Research Articles

Use of models for integrated assessment of ecosystem health

An argument is presented for a greater use of numerical models in integrated assessment of ecosystem health. Ecosystem health has many facets which are interconnected and interact, and which can only be measured in integrated assessments. Modelling is an essential feature of integrated assessment being one of the few ways human groups can form a consensus understanding of the complex dynamics which occur. Functional assumptions are made explicit. The argument is expanded in response to a series of key questions: What is ecosystem health? How do we do integrated assessments? What is modelling? What are some successful examples? What should one conclude? The answers are illustrated with references to the International Joint Commission's program to develop and implement Remedial Action Plans for the Great Lakes' Areas of Concern, particularly in the Bay of Quinte, Lake Ontario. Three recommendations are offered: (i) Increase the use of models, (ii) Build models with existing data and hypotheses before initiating new programs, and (iii) Allow for iterative model development but be prepared to build a new model when a new problem arises.

Using technology to access regional environmental information

Distinctions between holistic and presciptive technologies, and holistic and reductionist science are a backdrop to examination of two widespread environmental problems: eutrophication in the Bay of Quinte, Lake Ontario, and acidification of lakes in eastern Canada. Evidence is presented on a shift from prescriptive toward holistic approaches. Holistic solutions to technological limitations are discussed with emphasis on the interactive procedures people use to solve problems, rather than on the physical tools which are often employed in a prescriptive manner. Local gathering and integration of environmental information is presented as the key to macro-environmental assessments. Recommendations stress (i) the need for ecologists in every ecosystem, (ii) training with emphasis on problem-solving techniques, (iii) wide-spread use of microcomputers, a potent holistic technology, to transfer information and concepts, and (iv) local selection of indicators with the advice that they be simple and biotic.

Glacial and early postglacial lacustrine environment of a portion of northeastern Lake Ontario

A deep channel in bedrock extending to more than 25 m below sea level occurs along the north shore of the otherwise uniformly shallow Kingston basin of Lake Ontario. Bathymetric and subbottom acoustic data are used to map the topography of the channel and to reconstruct its late glacial and postglacial sedimentary history. The results are interpreted as showing that the large channel and smaller channels nearby were created by high-velocity subglacial meltwater flow. Acoustic facies assemblages of sediments deposited in the channels record patchy deposition, or deposition followed by partial erosion, of glacial sediments on the bedrock of the channel floor, followed by deposition and episodic erosion of glaciolacustrine sediment in a high-energy, ice-proximal lake. Palaeoslope analysis confirms that the early Holocene low-water phase of Lake Ontario resulted in the development of a fluvial system in part of the channel. Water level was controlled by a sill at Kingston. Kingston basin, the Bay of Quinte, and possibly, for a short time, a much larger area of the upper Great Lakes drained through the channel. However, for most of the period, until it was flooded by the rising waters of Lake Ontario, the channel was occupied by a small river on a wide floodplain or it was flanked by broad marshes.

Submerged Macrophytes in Lake Ontario: Current Knowledge, Importance, Threats to Stability, and Needed Studies

The submerged limnetic community in Lake Ontario includes algae, bryophytes, and about 30 species of angiosperms. Their distribution is accurately known in some areas but not lake-wide, and a whole-lake survey is recommended. In nutrient cycling, submergents act as sinks during the summer; metals and metalloids occur in high concentrations in tissues from some areas. Known herbivores include invertebrates, fish, and waterfowl. Stands are necessary for many fish taxa as breeding or nursery habitats, and for waterfowl, but may be damaged by carp (Cyprinus carpio). Stability has been affected by water levels, sedimentation, wave and ice movement, invasive species, herbivory, eutrophication and turbidity, and contaminants. Recovery after control of P loading has occurred in Irondequoit Bay but is delayed by turbidity in the Bay of Quinte.

Methods for fractionation of organic phosphorus in sediments

Fractionation of the organic phosphorus (P o) in sediment samples from the Bay of Quinte (BOQ) was carried out using two independent methods. The total P o in both cases was similar, but there was some variation in the amounts in individual fractions. The methods originally developed for application to soils is recommended because the fractions conform with well-known operationally-defined sediment components. The relative amounts of P o in five sediments were in all cases in the order: residualP o > fulvic P o > humic P o > labile P o.

Effects of Winter Temperature and Predation on the Abundance of Alewife ( Alosa pseudoharengus) in the Bay of Quinte, Lake Ontario

Alewife ( Alosa pseudoharengus) abundance in the Bay of Quinte, Lake Ontario, was monitored with a bottom trawl survey from 1972 to 1987. Prior to 1977, alewife catch-per-effort (CPE) was high in all areas of the bay but declined drastically following unusually cold winters in 1976–77 and 1977–78. Beginning in 1980, alewife CPE recovered in the lower bay, adjacent to Lake Ontario. This recovery was not observed in the upper bay where predation by a resurgent walleye ( Stizostedion vitreum) population maintained the reduced numbers of alewife. We conclude that walleye predation has played an important role in generating differences in alewife abundance between the upper and lower bays since 1980. There is a negative correlation between adult alewife CPE and young-of-year (YOY) alewife CPE suggesting that intraspecific predation is an important factor in the production of YOY alewife in the Bay of Quinte. Recruitment mechanisms for alewife in the Bay of Quinte may depend more on intraspecific predation, in contrast to Lake Ontario where intraspecific competition for zooplankton has been hypothesized as a limiting factor.

Experimental Use of Dialysis Chamber Arrays to Study P-Fluxes in the Bay of Quinte, 1987

To study the internal phosphorus load in the Bay of Quinte, Lake Ontario, dialysis chambers were set in an array mounted on a platform at the sediment/water interface. Two sets of arrays were used, one set was sampled weekly and the other bi-weekly. Chamber samples were analysed for total phosphorus and dissolved oxygen, and temperature and pH were measured. Up-facing array tubes also acted as settling traps and, from these, quantities of trapped material and contents of organic carbon and organic nitrogen were measured. Sediment samples were recovered at the array sites, and temperature, pH, Eh, color, and near surface layer structures were recorded. The arrays were used to estimate proportions of the internal phosphorus load derived from degradation of fresh particulates, at or near the base of the water column, and partly aged bed material. Phosphorus released from partly aged lake bed sediment provided about 20 percent of the internal load at Hay Bay, but the bed acted as a sink for much of the time at Picton. At Hay Bay, sediment oxygen consumption rates were high, averaging more than 0.6 g 0 2 m −2 d −1. Higher oxygen consumption rates characterized Picton sediments during the late summer and early fall, and these were accompanied by a slight increase in the rate of phosphorus release. Combined mean P-reflux values derived from these experiments were higher than expected from model predictions based on past Bay of Quinte studies. The higher values may be caused by very rapid degradation of trapped material in the up-facing array tubes due to the presence of excessive numbers of benthic invertebrates.

Metal contamination in sediments and biota of the Bay of Quinte, Lake Ontario, Canada

Metal contamination in sediments and biota of the Bay of Quinte, Lake Ontario, Canada

Some Problems Affecting the Assessment of Great Lakes Water Quality Using Benthic Invertebrates

The value of benthic macroinvertebrates as indicators of water quality increases with our understanding of the ways in which environmental and methodological factors can affect the results of field studies. When such factors are taken into account, the benthos accurately reflect changing conditions as demonstrated by long-term studies in southern Lake Michigan and Bay of Quinte, Lake Ontario. However, most studies have employed different field techniques and have been conducted at different times of the year. Some of the effects of such differences are illustrated through analysis of data collected by the Great Lakes Institute (University of Toronto) during the mid-1960s. These and other data suggest that timing of field work will reflect life cycle events such as recruitment, migration, and sexual maturity, all of which influence apparent water quality. Texture of the substratum can have similar effects, but these are not uniform across major taxonomic groups.

Biogenic silica as an estimate of siliceous microfossil abundance in Great Lakes sediments

Biogenic silica concentration (BSi) in sediment cores from the Great Lakes is evaluated as an estimate of siliceous microfossil abundance. A significant linear relationship was found between measured BSi and diatom valve abundance for sediment cores from the Bay of Quinte, Lake Ontario, Lake Erie, Lake Michigan and Lake Superior and between measured BSi and diatom biovolume for Lake Erie, Lake Michigan, and Lake Superior but not for Lake Ontario. Diatom silica predicted from diatom species abundance and an estimated silica content per cell in the Lake Erie cores accounted for 117% and 103% of measured BSi, respectively. By contrast, predicted diatom silica could only account for 28% of measured BSi in the Lake Michigan core and only 25% in the Lake Superior core. A few large diatoms with a large silica content per cell comprised a major portion of predicted diatom silica in all cores. The discrepancy between chemically measured BSi and the silica predicted from diatoms in the Lake Michigan and Lake Superior cores was partially due to the inability of the regression model, used to estimate diatom silica content, to account for different degrees of silicification in the diatom asemblages from the more dissolved silica rich Lake Michigan and Lake Superior.

Effects of Net Length and Set Time on Fish Catches in Gill Nets

Abstract The effects of varying net length and set time on fish catches in gill nets were studied at two sites in the Bay of Quinte, Lake Ontario. A latin square design was used (four locations per site over four nights); either net length was varied, from 25 to 200 yd over 12 h, or set time was varied, from 1.5 to 12 h with 50 yd of net. Treatment, location, and date effects on catches from each site were analyzed by a multiple regression model. Net length effects on catch per unit of effort (CPUE) were negligible for total and some fish species catches; CPUE for walleyes Stizostedion vitreum decreased with increasing net length. Set-time effects on total CPUE were significant; the CPUE of white perch Morone americana increased with set time, but CPUEs for yellow perch Perca flavescens, alewives Alosa pseudoharengus, and walleyes decreased. The results were attributable to specific differences in activity patterns and net-saturation effects. We concluded that use of gill-net catches as indices offish abu...

Production by the Amphipod Pontoporeia hoyi in South Bay, Lake Huron

Pontoporeia hoyi was the dominant profundal benthic macroinvertebrate comprising 70–90% of animals collected and averaging close to 2100 m−2 in the main profundal basin of South Bay, Lake Huron. Almost all production occurred in the profundal zone (1.15 g∙m−2∙yr−1) compared with the sublittoral zone (0.03 g∙m−2∙yr−1), attributable to a preference by older P. hoyi for cooler temperature. Production/biomass (P/B) averaged 1.4∙yr−1 in the profundal zone at mean annual temperature of 4.7 °C and 3.1∙yr−1 at 7.5 °C in the sublittoral zone. Instantaneous growth rates were the same as in the Bay of Quinte and adjacent Lake Ontario where production was six times that in South Bay. A similar difference in phytoplankton production occurred between the areas. Differences in biomass accounted for variation in P. hoyi production in the two areas. The South Bay data provide further evidence that benthic macroinvertebrate biomass reflects production consistent with values of P/B determined by temperature.

Production and Biomass Size Spectra in the Bay of Quinte, A Eutrophic Ecosystem

From the 1940s on, the Bay of Quinte was subjected to increased point-source phosphorus loading. This and other stresses (exploitation, fish species invasion, and perhaps climate fluctuation) altered the productivity of the ecosystem and community structure. In the late 1970s, point-source loading was greatly reduced. At the same time, walleye (Stizostedion vitreum vitreurn) produced the largest year class ever recorded and surged to abundance greater than those seen in the 1950s before its collapse. Also, the dominant invader white perch (Morone americana), which had flourished in the 1960s and 1970s, was almost eliminated by a low-temperature kill. Studies of the bay ecosystem before and after these events indicated that while nutrients and algae responded to changes in nutrient loadings, changes in secondary producers hinged on the changes in the fish community. Use of Borgmann's biomass size spectrum model provides a focus for the interpretation of nutrient- and predator-related changes in biomass distribution. Deviations of the biomass spectrum are interpreted. The biomass and production spectra are linked to both phosphorus concentrations, observed and predicted, and to fishery exploitation rates. The results suggest that while nutrients control the overall biomass of the ecosystem and the slope of the biomass spectrum, trophic interactions and perturbations (e.g. exploitation) determine the degree to which a smooth biomass spectrum is achieved.

Recent Changes in the Aquatic Food Web of Eastern Lake Ontario

During the past 10 yr there have been dramatic increases in piscivorous populations of walleye (Stizostedion vitreum) in the Bay of Quinte and of planted lake trout (Salvelinus namaycush) and double-crested cormorants (Phalacrocorax auritus) in the Kingston basin of Lake Ontario. This paper documents changes in the prey stocks shared by these piscivores, including reduction in size and abundance of the slimy sculpin (Cottus cognatus) with subsequent stock equilibration and unabated reduction in the size and abundance of rainbow smelt (Osmerus mordax), both owing to predation pressure from the lake trout. The third primary prey species, alewife (Alosa pseudoharengus), has not yet suffered severely from the depredations of the piscivores. Symptoms of the effects are discernible, however, and the implications of a possible collapse are discussed. Lake trout survival and growth have not yet been affected by the changes in prey availability, but their diet has shifted both in response to their own expanded size composition and relative abundance of the three prey species. Increased utilization of alewife makes the hunting of the trout more pelagic. Problems of obtaining representative samples of the prey are discussed.

Priority Site Selection for Degraded Areas Based on Microbial and Toxicant Screening Tests

Abstract The results of a study to evaluate the suitability of a variety of microbiological, biochemical and bioassay tests to become part of a battery of test procedures to identify degraded or degrading water bodies, are presented. Data for this study were obtained from 51 inshore sampling sites along the north shore of Lake Ontario from Kingston to Niagara River. Data examination indicated that microbial population, biochemical or bioassay tests performed independently do not provide realistic estimates of priority concern areas and that the battery approach is required. From this study the sampling sites of highest concern were: Humber River STP out fall, mouth of Mimico Creek, mouth of Credit River and Bay of Quinte near the Belleville STP outfall.

Biomass of Freshwater Crustacean Zooplankton from Length–Weight Regressions

We present equations for calculating dry weight from body length for 14 common and widely distributed taxa of crustacean zooplankters; these were generated by regression from weights of individuals chosen from the range of lengths observed for each taxon, usually three replicate weights at each of five lengths. We include regressions for ovigerous and nonovigerous cladocerans, plus nauplii, early copepodites, and adult males and females for the copepods (30 length–weight relationships) and individual weights for given stages of copepods. We calculated the seasonal variation in crustacean biomass for a station in the Bay of Quinte, Lake Ontario, and for each of the three basins of Lake Erie. Biomass was dominated by Cladocera for both lakes, with Copepoda predominant in the spring. Mean individual dry weights varied seasonally for all taxa, confirming previous findings.

Historical Relationships between Phosphorus Loading and Biogenic Silica Accumulation in Bay of Quinte Sediments

Sediments from Warwick's 1972 Glenora-B core from the Bay of Quinte, Lake Ontario, were analyzed to compare the historical relationship between the accumulation of biogenic silica (BSi) and total phosphorus (TP). The similarities in patterns provide evidence that increased phosphorus (P) inputs caused increased diatom production and BSi accumulation. BSi accumulation increased soon after initial European settlement by French Sulpicians in 1669 and reached maximum levels during the early 1850s when forest clearance and erosion of the deforested drainage basin increased sediment accumulation rates 110-fold compared with rates before 1669. Maximum rates of BSi and TP accumulation increased 170-fold and 150-fold, respectively, during the same period. Ratios of BSi:TP were about sixfold greater in the sediments deposited after 1888 than in those deposited prior to 1669, indicating that the proportion of available P in TP inputs increased with increased disposal of domestic sewage into the bay as populations shifted to urban centers. Increases in BSi accumulation above the Ambrosia horizon (dated at 1852) indicate that sediments can be a significant sink for BSi. Although the onset of Si depletion cannot be confirmed with data from this core, there is clear evidence that BSi accumulation increased as the result of increased P inputs.

The210Pb and137Cs profiles in sediment cores from Bay of Quinte, Lake Ontario

210Pb,226Ra and137Cs profiles have been measured for sediment cores from three locations in Bay of Quinte, Lake Ontario, Canada. Compaction of the sediment with depth of burial is taken into account in calculating recent sedimentation rates and age profiles at these locations from the excess210Pb profiles. The rates are 1.803+0.592 cm·y−1 (0.254±0.083 g·cm−2·y−1), 0.101±0.017 cm·y−1 (0.036+0.006 g·cm−2·y−1), and 0.795±0.218 cm·y−1 (0.076±0.021 g·cm−2·y−1). The corresponding fluxes of excess210Pb to sediment/water interface are determined to be 1.652, 0.253, and 1.123 pCi·cm−2·y−1, respectively. The anomalies observed in the radionuclide concentration profiles are attributed to physical mixing. It is postulated that the significantly higher flux of210Pb observed at one of the locations is due to inputs from Trent River which joins the Bay near this location.

Postsettlement Diatom Succession in the Bay of Quinte, Lake Ontario

Siliceous algal microfossil assemblages deposited in the Bay of Quinte prior to European settlement consist of low numbers of benthic diatoms and chrysophyte cysts. Early settlement activities are marked by qualitative changes in the flora and small increases in microfossil flux. Events associated with the Ambrosia horizon produced a rapid transition from assemblages characteristic of oligotrophy environments to those characteristic of eutrophic waters and a large increase in microfossil flux. This was followed by a period of decreasing siliceous microfossil flux and reestablishment of less eutrophic species ca. 1853–61. Minimum siliceous algal microfossil flux and highly atypical assemblages occurred in the period ca. 1879–88, which corresponds to the period of intensive mining activities in the Bay of Quinte watershed. Maximum flux of siliceous microfossils occurred ca. 1900 and declined thereafter, although composition of assemblages deposited indicates increasing eutrophy and displacement of summer-blooming species. We interpret this as evidence of beginning of summer silica limitation. Based on microfossil evidence, the modern eutrophic flora of the bay was established by 1928.

The Expansion of White Perch,Morone Americana, In the Lower Great Lakes

White perch, Morone Americana, first appeared in the Laurentian Great Lakes system in 1951 and flourished in the Bay of Quinte, Lake Ontario throughout the 1950s and 1960s. The species extended its range to Lake Erie and Lake St. Clair and more recently (1983) to Saginaw Bay, Lake Huron. Self sustaining populations of white perch are now established in western Lake Erie (1974) and Lake St. Clair (1979). Factors contributing to successful colonization by white perch include: suitability of habitat within the range, ability to spawn over a variety of substrates, and high egg production.