The objective of this thesis was to assess the physical (concentrations, durations, and sedimentation) and biological effects of total suspended solids (TSS) in Arctic lakes following in-lake construction of dikes. TSS concentration and duration estimates were applied in a Severity of Ill Effects model which predicted possible habitat degradation and a reduction of feeding of salmonids with no significant difference between stations (ANOVA, p=0.153). Benthic invertebrates collected inside suspended sediment containment curtains showed a decrease in richness and abundance (Tukey’s, p<0.05), with no effects elsewhere. Stable isotope analysis from lake trout and arctic char muscle tissue suggested no differences in isotopic signatures following TSS exposure, but stable isotope analysis of stomach contents in lake trout had a significant increase in δ15N compared to the reference basin (Tukey’s, p<0.05). These findings suggested that lake trout adapted their food sources under moderate TSS exposure and benthic invertebrates rapidly recovered to pre-disturbance values. / Agnico-Eagle Mines Limited: Meadowbank Division and the University of Guelph; Research approved by Department of Fisheries and Oceans & Nunavut Impact Review Board

Bioavailability of trace metals in urban contaminated soils was investigated to relate chemical extraction efficiencies with biological effects. / Results from a Collembola reproduction bioassay showed minimal toxicity suggesting limited bioavailability. Chemical extractions were carried out on these urban soils. The sodium acetate extraction was the best predictor of the biological effects of Cd while the biological effects of Zn were best explained by a water extraction. / An earthworm uptake bioassay was done to quantify the bioavailable fractions. Cadmium, Cu, Pb and Zn accumulated in Lumbricus terrestris L. The sodium acetate extraction was the best predictor of Cd uptake while calcium chloride extraction best predicted Zn uptake by earthworms. / Treatments were made to urban soils to immobilize the metals and reduce their bioavailability. The metal concentrations were so low in the soils that the effects of the treatments could not be measured. / Collembola and earthworms are good indicators of trace metal bioavailability and should be included in the evaluation of contaminated soils.

Conservation of streams involves an understanding of their physical , chemical and biological entities. SASS5 is a biomonitoring method developed to monitor the habitat quality of a water body. It is based on differential scores attributed to various macroinvertebrate families with varying degrees of sensitivity to anthropogenic impact. This method , however, does not assess impacts on particular species. Odonata are good candidates for study at the species level as they are well researched and males are easily identified . As adults, they are known to be sensitive indicators of both riparian and river conditions. Yet Odonata cannot be an umbrella taxon for all other taxa . Therefore, the main aim of this study is to determine the complementarity of the two metrics (Odonata assemblages and SASS5), establishing whether Odonata assemblages offer additional information on, or insight into, riverine habitat quality as portrayed by SASS5. To accomplish this, certain objectives were addressed . 1) The variation of SASS5 scores and 2) Odonata assemblages between river systems, structural habitat types (open or closed canopies) and compositional habitat types (indigenous or alien vegetation). 3) Whether SASS5 scores vary to the same extent, and, 4) on the same spatial scale (river system and point localities) as Odonata abundance and species richness . The relationship between these two metrics was determined along three rivers in the Pietermaritzburg basin. Sampling units (SUs) with extremes in vegetation structure (sunlight and shaded SUs) and vegetation composition (alien or indigenous) were selected. Using this range of environmental conditions placed environmental extremes on the macroinvertebrate populations at point localities and having three different river systems added the dimension of variation over a broader scale, thus stretching the two metrics to investigate whether both responded similarly or in different ways. Results indicated that both metrics provide a similar portrait of overall river conditions. At the smaller spatial scale, the Odonata assemblage, unlike SASS, was highly sensitive to the riparian vegetation. Odonata species were less sensitive to vegetation composition but differentially sensitive to vegetation structure. However, landscape context is also important, with point localities being affected by the neighboring dominant habitat type. Larval Odonata alone did not provide this information. Overall, aquatic macroinvertebrates and adult Odonata provide a highly complementary pair of metrics that together provide large spatial scale (river system) and small spatial scale (point localities) information on the level of impact of stressors such as riparian invasive alien trees. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

The excessive deposition of fine inorganic sediment (<2 mm) is a major pathway by which agricultural land uses exert pressure on stream ecosystems. However, less well understood are the underlying mechanisms driving threshold biotic responses and the ecological consequences of community changes to sedimentation. Reviewing the literature, I found that sedimentation can affect algal and detrital pathways, and invertebrate community composition may show abrupt shifts with increased sediment. Moreover, functional changes to communities potentially leads to simpler food webs, with altered interactions and decreased ecosystem function. After identifying these knowledge gaps, I conducted survey and experimental research using agricultural streams on the Canterbury Plains of New Zealand’s South Island. Results from my survey of 30 streams along a sedimentation gradient showed that pollution-sensitive invertebrates (% EPT; Ephemeroptera, Plecoptera, Trichoptera) demonstrated threshold responses to sediment that varied with spatial scale, and change-point analysis indicated marked declines beyond 20% fine sediment covering streambed reaches. Structural equation modeling indicated that decreased habitat availability was a key mechanism contributing to these changes. To better understand the functional consequences of altered community structure, I investigated food webs in 12 streams along the gradient. The results showed a compression of community trophic niche space, suggesting that in particular, primary consumers became trophically more equivalent. The simplification of stream food webs with increasing sediment appeared to be the result of functional changes to invertebrate communities, with fewer specialised consumers, and shifts in the availability of basal resources. Using field and laboratory experiments investigating litter breakdown and invertebrate feeding, I found that the net consequence of functionally less diverse stream communities with increased sediment was impaired ecosystem function, demonstrated by a reduction in litter breakdown rates. The reduction of detrital resource availability through burial by sediment in laboratory mesocosm experiments strongly influenced detrital consumption rates, thus leading to reduced growth and survival of detritivorous caddisflies. The survey and experimental results support my postulate that sediment deposition causes environmental stress by degrading benthic habitat and making associated food resources (e.g., periphyton and leaves) less available. Overall, my results have provided new insights into sediment impacts on stream communities and have furthered our understanding of how these changes affect the structure and functioning of stream ecosystems.

The aim of this thesis has been to: 1) assess the state of pollution in the two study areas and relate them to recent changes found in the Kattegat - Belt Sea area; 2) examine the observed spatial and temporal variability in species composition, abundance and biomass in Arhus Bay and the Formes area and relate the variability to antropogenic and natural causes; 3) discuss and assess methods, particularly for the estimation of secondary production and the use of multivariate analyses as methods for examining changes in macrozoobenthic communities. Macrozoobenthos were sampled at 15 stations in Arhus Bay, Denmark from 1985 to 1991 while data from Formes (reference area) included 55 sampling stations from 1986 to 1990. Monthly sampling took place at one station in Arhus Bay in 1990 and 1991. The two study areas are both situated on the eastcoast of Jutland in the Kattegat - Belt Sea area at 13-17 m depth and both receive waste water from long sea outfalls. Although both areas are Subjected to salinity stratification for most of the year, the exposed position of the Formes area on the open Kattegat coast prevents it from suffering from severe oxygen deficiencies, unlike the Arhus Bay which is a sheltered, semi-enclosed sedimentation area where oxygen concentrations in the bottom water can be very low. At Formes the sediment is sandy while it is silty in Arhus Bay. The spatial and temporal variability in the benthos in Arhus Bay could to a great extent be explained by the variation in 7 important species: Abra alba, Corbula gibba, Mysella bidentata, Nepthys hombergii, N. ciliata, Ophiura albida and Echinocardium cordatum. The fluctuations in the number and biomass of A. alba had a pronounced effect on the total abundance and biomass in Arhus Bay. The severe winter of 1986/87 with low temperatures and oxygen depletion under the ice cover practically eliminated A. alba from the bay. A. alba quickly recolonized the area and was found in high numbers in 1988. Studies of growth of A. alba in 1990 and 1991 showed that by the end of 1990 the population had reached an average length of 10 mm while the average shell length was only 5 mm by the end of 1991. The difference between the two years could be attributed to the difference in sedimentation of phytoplankton from the water column. As in other parts of the Kattegat - Belt Sea area, Arhus Bay has experienced low oxygen concentrations in the bottom water in late summer early autumn throughout the 1980s. Only the oxygen depletion under the ice cover in early spring 1987 and the local oxygen deficiencies south of the outlet in 1989 and 1990 actually killed parts of the benthic fauna. Apart from 1981, the oxygen deficiencies have thus been less severe in Arhus Bay than in other parts of the southern Kattegat in the 1980s. The number of species, abundance and biomass decreased at Fornres from 1980 to 1985 while the discharge of BOD was fairly constant during the same period. From 1986 there was a slight decrease in the discharge of BOD but a considerable increase in the number of species, abundance and biomass. At least for the second half of the 1980s there was no straightforward relation between the organic enrichment from the outlet and species composition, abundance and biomass and suggests that other factors are also important influencing the fluctuations in the benthic fauna. Estimates of total secondary community production were found to be very dependent on the method used. The method described by Brey (1990) was found acceptable for estimating secondary production in Arhus Bay but care should be exercised when comparisons are made with other areas where different methods have been used to estimate production. Secondary production was estimated more accurately for some of the abundant species in Arhus Bay on the basis of monthly samplings by the method described by Crisp (1984). Among the multivariate analyses the Detrended Correspondence Analysis (DCA) and nonmetric Multidimensional Scaling (MDS) proved to be the most successful with the Arhus Bay and Fornes data sets. Two Way INdicator SPecies ANalysis (TWINSPAN) did not work well with the Fornes data because it imposed discontinuities on data sets with continous variation in distribution of species among samples. As community types existed to a certain degree in Arhus Bay TWINSPAN worked well with these data. DCA and MDS were found to be useful techniques for analysing large data sets because they can summarize the data matrices to a manageable form and find possible patterns in the data sets. The results of the analyses can then be used as starting point for more detailed investigations of single species/samples or groups of species/samples. By using different transformations of the raw data the role of dominant or rare species can be assessed. A major 'problem in the assessment of multivariate techniques is the lack of external standards to compare with. The results of multivariate analyses must therefore be assessed critically on the basis of a careful examination of the species list combined with the knowledge and experience of the investigator. The methods used all had their advantages and limitations but each of the different methods added some important information to the picture of the benthic community in Arhus Bay and Fornes. It was thus an considerable advantage to use several different methods to analyse the spatial and temporal variability in the benthic fauna in relation to antropogenic and natural causes.

Hemlock woolly adelgid is an invasive herbivore causing extensive mortality of eastern hemlock, an important foundation species that provides stable conditions influencing biological communities. Hemlock is often found in riparian areas and following its decline, broadleaved species, including birch, beech, and rhododendron, will replace it. These plants differ from hemlock in patterns of canopy cover and leaf properties, which influence conditions and resources within streams. My goal was to evaluate potential impacts of adelgid-induced alterations to riparian canopies and litter on benthic communities and litter breakdown in streams. I characterized benthic invertebrate communities, litter colonization and litter breakdown in streams with hemlock- or deciduous-dominated riparian canopies. Riparian canopy influenced abundance of some invertebrates, but litter species influences a range of benthic colonizers. Rhododendron and beech litter generally support more invertebrates and decomposes more slowly than birch or hemlock. When invertebrates are excluded, broadleaved litter breakdown is more hindered than hemlock breakdown. My findings suggest that invertebrates may be more affected by future increases in broadleaved litter inputs to streams than by hemlock litter loss. This is significant because benthic invertebrates are important for in-stream litter processing and are linked to aquatic and terrestrial food webs.

Common carp (Cyprinus carpio) have been hypothesized to contribute to declines in aquatic macrophytes, waterfowl, and water clarity in Delta Marsh, an 18,500 ha freshwater coastal wetland on Lake Manitoba, Canada. Ten ponds (1-13 ha) were chosen for a two-year experimental manipulation study. Following a year of baseline monitoring, manipulations were conducted in 2002. To facilitate access by carp into isolated ponds, channels were blasted from the main marsh into two ponds. Meanwhile, to restrict or exclude carp access into ponds, channels were either screened or diked to four ponds. Two connected and two isolated ponds functioned as controls. Although common carp were the original subject of the study, it became apparent that hydrological connection to the surrounding marsh had a paramount importance on the abundance and diversity of the fish, amphibian and water-column invertebrate communities. Connectivity, or lack of connectivity, played an important role in the distribution of the fish community, and subsequently the composition and abundance of water-column invertebrates and amphibians. Ponds with direct connection had diverse, mixed-species fish assemblages, with fewer invertebrates and amphibians. Ponds with restricted connections had fish communities composed of tolerant small-sized species and increased abundance of invertebrates and amphibians. Ponds that lacked connection could freeze and lose all fish, and had higher numbers of invertebrates and amphibians. An absence of adult common carp may have been responsible for increased amphibian numbers in the screened ponds, however more study is needed. Confounding impacts of fluctuating water levels made it impossible to implicate common carp for most changes observed within ponds in Delta Marsh.

Bakalauro darbo tikslas – pasirinktose Mūšos upės vietose nustatyti makrozoobentosinių organizmų grupes ir pagal juos įvertinti upės vandens kokybę. Uždaviniai – atlikus išsamią literatūros analizę, motyvuotai pasirinkti esamą arba sukurti tyrimų metodiką; pasirinktose Mūšos upės vietose surinkti ir apibūdinti makrozoobentosinius organizmus ir pagal gautus rezultatus nustatyti vandens kokybę skirtingose upės vietose; gautus biologinių tyrimų rezultatus palyginti su anksčiau atliktų vandens kokybės tyrimų rezultatais. Darbo objektas – Mūšos upė įtekant ir ištekant iš Pasvalio rajono. Makrozoobentosiniai organizmai rinkti 2013 metų rugpjūčio 21–22 dienomis. Tyrimo metodika pagrįsta LAND 57–2003 dokumente pateikiama Danijos upių faunos indekso (DUFI) metodu pagal Friberg'ą ir BMWP balų metodu. Makrozoobentosiniai organizmai buvo renkami renkamojo metodo principu. Gauti rezultatai rodo, kad ties įtekėjimu į Pasvalio rajoną Mūšos upės vandens kokybė, vertinant pagal makrozoobentosą, taikant DUFI metodą priskiriama vidutinei vandens kokybės klasei (pagal BMWP – geros kokybės), nes tyrimais nustatyta, kad čia vyrauja III klasės fauna (pagal BMWP – II klasės fauna). Ties ištekėjimu iš Pasvalio rajono Mūšos upės vandens kokybė, vertinant pagal makrozoobentosą, taikant DUFI priskiriama blogos vandens kokybės klasei (pagal BMWP – vidutinės), nes tyrimais nustatyta, kad čia vyrauja IV klasės fauna (pagal BMWP – III klasės fauna). Palyginus gautus rezultatus su ankstesnių tyrimų... [toliau žr. visą tekstą] / The aim of the Bachelor’s thesis is to identify individual groups of macrozoobenthos in the selected spots of the Mūša River and to assess the river water quality on the given basis. The objectives are as follows: a motivated selection of the existing methods of research or creation of new ones following a detailed analysis of the literature; macrozoobenthos collection in the selected spots of the river and the description of organisms collected and determining the quality of water in different locations by the results; comparison of the biological results with the findings from previous water quality studies. The subject of the thesis is the Mūša River flowing into and out of Pasvalys district. Macrozoobenthos organisms were collect 21 to 22 August 2013. The research methods were based on the Danish Stream Fauna Index (DSFI) by Friberg laid down in the document LAND 57-2003 and BMWP scoring method. Macrozoobenthos organisms were collected using the method of the elective principle. The findings show that at the inflow to Pasvalys District, the water quality in the Mūša River can be classified as the average water quality in terms of macrozoobenthos by DSFI (as good water quality by BMWP), as the study found the prevalence of class III fauna (Class II fauna by BMWP). At the outflow from Pasvalys District, the water quality in the Mūša River can be classified as the poor water quality in terms of macrozoobenthos by DSFI (as average water quality by BMWP), as the study found... [to full text]

Common carp (Cyprinus carpio) have been hypothesized to contribute to declines in aquatic macrophytes, waterfowl, and water clarity in Delta Marsh, an 18,500 ha freshwater coastal wetland on Lake Manitoba, Canada. Ten ponds (1-13 ha) were chosen for a two-year experimental manipulation study. Following a year of baseline monitoring, manipulations were conducted in 2002. To facilitate access by carp into isolated ponds, channels were blasted from the main marsh into two ponds. Meanwhile, to restrict or exclude carp access into ponds, channels were either screened or diked to four ponds. Two connected and two isolated ponds functioned as controls. Although common carp were the original subject of the study, it became apparent that hydrological connection to the surrounding marsh had a paramount importance on the abundance and diversity of the fish, amphibian and water-column invertebrate communities. Connectivity, or lack of connectivity, played an important role in the distribution of the fish community, and subsequently the composition and abundance of water-column invertebrates and amphibians. Ponds with direct connection had diverse, mixed-species fish assemblages, with fewer invertebrates and amphibians. Ponds with restricted connections had fish communities composed of tolerant small-sized species and increased abundance of invertebrates and amphibians. Ponds that lacked connection could freeze and lose all fish, and had higher numbers of invertebrates and amphibians. An absence of adult common carp may have been responsible for increased amphibian numbers in the screened ponds, however more study is needed. Confounding impacts of fluctuating water levels made it impossible to implicate common carp for most changes observed within ponds in Delta Marsh.

The fate and bioaccumulation of a contaminant entering the marine environment through wastewater outfalls depends on the contaminant’s persistence and affinity for particles. The physical characteristics of the receiving environment, e.g. current velocity, sedimentary processes, and the availability of organic carbon are also important. However, these latter effects are not usually evaluated quantitatively. This thesis investigates the near-field accumulation in sediment and biota of particle-reactive polybrominated diphenyl ethers (PBDEs) entering coastal waters via two municipal outfalls: one discharging into a high energy, low sedimentation environment near Victoria, B.C., Canada; the other into a low energy, high sedimentation environment near Vancouver, B.C. We used 210Pb profiles in sediment box cores together with an advection-diffusion model to determine surface mixing and sedimentation rates, and to model the depositional history of PBDEs at these sites. A particularly important finding of this study is that the very high energy environment to the southeast of the Victoria outfall accumulates PBDEs despite not having net sediment accumulation. Although the discharge of PBDEs was much lower from the Victoria outfall than from Vancouver, some sediment PBDE concentrations were higher near Victoria. Most PBDEs were dispersed beyond the near-field at both sites, but a greater proportion was captured in the sediment near the Vancouver outfall where rapid burial was facilitated by inorganic sediment supplied from the nearby Fraser River. Clearly, treating wastewater to the same level, regardless of local oceanographic conditions, will not result in a uniform environmental footprint. Total PBDE concentrations in benthic invertebrate communities were higher near Vancouver than Victoria, despite lower concentrations in sediments, and correlated with organic carbon normalized sediment concentrations. Principal Components Analysis suggested uptake of individual PBDE congeners was determined by sediment properties (TOC, grain size), whereas PCB congener uptake was governed by physico-chemical properties (octanol-water partitioning coefficient). Our results suggest that sediment quality guidelines for PBDEs and likely PCBs may be more relevant if corrected to TOC content in sediment. In addition, where enhanced wastewater treatment increases the ratio of PBDEs to particulate organic carbon in effluent, nearfield benthic invertebrates may face increased PBDE accumulation. This underlines the need for source control of persistent organic contaminants, which cannot be broken down by conventional wastewater treatment. / Graduate