Periphyton was monitored monthly at four sites on the Waipara River from July 1999 to January 2002. Interactions with river flows, nutrients and invertebrates were examined to determine how these factors controlled periphyton development. Comparison of the Waipara River to other New Zealand streams indicated that periphyton biomass at the uppermost site (Site 1) was generally low to moderate. Further downstream, moderate to high biomass occurred at sites 2 and 4. Biomass at Site 3 was generally low, although some very high values occurred on occasions. Periphyton biomass at sites 2 and 4 exceeded periphyton guidelines for the protection of aesthetic/recreational values at least once during each full year monitored. In contrast, the guidelines were rarely exceeded at Site 1. Dissolved inorganic nutrients were generally poor indicators of the nutrient status of the river because of plant uptake. Cellular N and P values indicated nutrient enrichment at sites 2 and 4, which correspondingly had the highest biomass values. Conductivity tended to positively correlate with temporal and spatial patterns in periphyton biomass and was useful as a surrogate indicator of nutrient supply regimes. It correlated negatively with river flows, indicating higher nutrient concentrations may occur during reduced flows. Notable differences occurred in biomass development between periods of contrasting flow regimes. In particular, annual mean and maximum biomass at the three downstream sites was considerably higher during a period of low stable flows compared to a period of higher base flows. However, at the uppermost site, differences in biomass between these periods were much less pronounced. Invertebrate densities increased significantly with increasing periphyton biomass at the three downstream sites. There was little indication that invertebrates had any major control on periphyton biomass at these sites. However, at the uppermost site, although the invertebrate densities were generally much lower than at the other sites, they are more likely to have a controlling influence on periphyton biomass. Overall, the nutrient supply regime of the Waipara River is the primary controller on biomass development. Flow regimes (both frequency of disturbance and extent of low flows) operate as secondary controls of biomass.

Thesis (M.S.)--Ohio University, November, 2007. / Title from PDF t.p. Includes bibliographical references.

Physicochemical factors, algal diversity, taxonomic composition and standing crop were investigated across a broad gradient of AMD stress in streams and rivers. 52 sites were surveyed in the vicinity of Greymouth, Reefton, Westport and Blackball, on the West Coast, South Island. Seven sites in the Reefton area were sampled from April 2006 - February 2007 to establish changes over time in benthic algal communities of AMD and reference streams. Longitudinal change and ecosystem recovery were also investigated by sampling eight sites down Devils Creek, Reefton, and two of its tributaries. AMD has negative impacts on algal diversity, generally increases the dominance of certain taxa and, where metal oxide deposition or hydraulic disturbance are not great, can lead to algal proliferations. These proliferations were chlorophyte dominated, predominantly by filamentous Klebsormidium acidophilum. From the general survey a total of 15 taxa were identified from the most severely impacted sites (pH <3.6), which included both acidophiles and acidotolerant algae. Multivariate analyses strongly suggest that pH was the dominant factor controlling taxonomic occurrence of diatoms, macroalgae and the structure of the total assemblage. Other factors such as conductivity, metal oxide deposition, temperature, depth, month, geographic location and altitude were also important. Algal communities changed over time and this became more marked as AMD impact decreased. This was presumably due to AMD stressors reducing diversity, and thus the available scope for assemblage change. Longitudinal differences in assemblage structure within Devils Creek appeared to be in response to dilution of AMD in upper reaches and to changes in natural physical features such as gradient in mid and lower reaches. After a distance of 7.2 km the physicochemical effects of AMD and suspended clay inputs were minimal. At this site and at several previous sites, the assemblage exhibited a degree of recovery towards that found at unimpacted sites. A range of algae found in the broad scale-survey are potentially useful 'sensitive' indicators. These included: Heteroleibleinia purpurascens; Achnanthes oblongella; Oedogonium sp. and Spirogyra sp. In contrast: Euglena mutabilis; Navicula cincta; K. acidophilum; Microspora quadrata and Microthamnion kuetzingianum may be useful 'tolerance' indicators. These data show that AMD has a range of negative impacts on algae, and algae may be a useful tool for monitoring these impacts in West Coast streams.

The impacts of oil sands processed materials (OSPM) on phytoplankton and periphyton community growth and stable carbon and nitrogen isotopes were examined. Estimates of plankton and periphyton community growth, measured as chl a and dry weight, were low and similar in reference and OSPM reclamation wetlands. The use of stable isotope analyses revealed higher δ15N of plankton and periphyton in OSPM wetlands than reference wetlands, possibly due to increased TN concentrations in some OSPM wetlands. In the laboratory, water-soluble fractions (WSF) of two types of OSPM (mature fine tailings, MFT and consolidated tailings, CT) and an amendment material (peat-mineral mixture), potential fill materials in wetland or end pit lake reclamation, were examined for phytoplankton community growth and stable carbon and nitrogen isotopes. All WSF treatments had higher chl a compared to reference water and maximum growth was observed at a 50:50 ratio of peat:CT or peat:MFT. In general, WSFs of peat had the highest concentration of total nitrogen (TN) whereas WSFs of MFT had the highest total phosphorus (TP; 3x higher). The results suggested that the addition of peat as an amendment to OSPM (particularly for MFT), contributing additional TN, could improve phytoplankton community growth in oil sands reclamation. At higher percentages of MFT WSF, there was increased turbidity due to fine clay particles that likely contributed to reduced phytoplankton growth. Turbidity could be an important factor limiting phytoplankton growth and thus reducing dietary resources and biological detritus (via sedimentation) in the initial development of an end pit lake. The WSFs also promoted the unfavourable growth of filamentous algae, highest at intermediate concentrations of peat and CT WSFs and inhibited in MFT WSFs due to light limitation. Stable N isotopes of plankton and filamentous algae suggests that 15N enrichment of algae could be a useful indicator of nutrient inputs, including OSPM seepage into natural aquatic systems, for oil sands regional monitoring programs.

That ecological and evolutionary processes can take place on the same time scale is a recent insight. Today we also know that they are directly linked to each other. In the lake Tåkern, in year 2000, there was a structural change when phytoplankton declined and submerged vegetation, mainly stoneworts began to spread. This led to evolutionary changes in the aquatic sowbug, Asellus aquaticus which had previously been limited to the reed, most likely feeding on detritus. But then, sowbugs could exploit the new habitat in stoneworts and a new food resource in terms of periphyton. The aim of this study was to investigate whether the differentiation of the populations has led to specialization in the ecological roles of sowbugs as shredder of coarse detritus and grazer of periphyton. The study was a laboratory experiment in which groups of sowbugs were feeding on decomposing alder (Alnus glutinosa) leaves or periphyton growing on tiles. The results showed that there was no specialization in the habitat-specific food. However, reed animals had a greater (31 %) grazing effect than the stonewort animal on periphyton. There was also a non-significant tendency for reed animals to consume more leaves than the stonewort animals. The conclusion is that the different populations are not different in their functional roles, but the reed animals consume approximate 25 % more food than the stonewort animals, possibly because of higher activity.

The global climate is predicted to go through great changes in the 21st century, which will have impacts on ecosystems all over the world. Aquatic ecosystems will be affected by higher annual temperatures and increased runoff from surrounding terrestrial areas. The increased runoff will cause more terrestrial organic matter (TOM) to reach the waters, which will elevate levels of dissolved organic carbon and nutrients. The higher temperature, changed water color and increased nutrient concentration are together bound to affect aquatic systems, but exactly how the systems will respond is yet unclear. The aim of this study was to investigate how periphyton and benthic grazers will react to higher temperatures and elevated amounts of TOM in the water. This was done by measuring production of periphyton and growth rates of the snail species Gyraulus acronicus when placed in treatments with higher temperature, more TOM or a combination of these two. Higher temperature was found to have a negative effect on periphyton production, while increased amounts of TOM alone had a positive effect, and the combination of these two lowered production. The results on snail performance were in most cases non-significant, but the results still suggest that possible future effects of more TOM and higher temperature on the snails will be negative.

The impacts of oil sands processed materials (OSPM) on phytoplankton and periphyton community growth and stable carbon and nitrogen isotopes were examined. Estimates of plankton and periphyton community growth, measured as chl a and dry weight, were low and similar in reference and OSPM reclamation wetlands. The use of stable isotope analyses revealed higher δ15N of plankton and periphyton in OSPM wetlands than reference wetlands, possibly due to increased TN concentrations in some OSPM wetlands. In the laboratory, water-soluble fractions (WSF) of two types of OSPM (mature fine tailings, MFT and consolidated tailings, CT) and an amendment material (peat-mineral mixture), potential fill materials in wetland or end pit lake reclamation, were examined for phytoplankton community growth and stable carbon and nitrogen isotopes. All WSF treatments had higher chl a compared to reference water and maximum growth was observed at a 50:50 ratio of peat:CT or peat:MFT. In general, WSFs of peat had the highest concentration of total nitrogen (TN) whereas WSFs of MFT had the highest total phosphorus (TP; 3x higher). The results suggested that the addition of peat as an amendment to OSPM (particularly for MFT), contributing additional TN, could improve phytoplankton community growth in oil sands reclamation. At higher percentages of MFT WSF, there was increased turbidity due to fine clay particles that likely contributed to reduced phytoplankton growth. Turbidity could be an important factor limiting phytoplankton growth and thus reducing dietary resources and biological detritus (via sedimentation) in the initial development of an end pit lake. The WSFs also promoted the unfavourable growth of filamentous algae, highest at intermediate concentrations of peat and CT WSFs and inhibited in MFT WSFs due to light limitation. Stable N isotopes of plankton and filamentous algae suggests that 15N enrichment of algae could be a useful indicator of nutrient inputs, including OSPM seepage into natural aquatic systems, for oil sands regional monitoring programs.

Physicochemical factors, algal diversity, taxonomic composition and standing crop were investigated across a broad gradient of AMD stress in streams and rivers. 52 sites were surveyed in the vicinity of Greymouth, Reefton, Westport and Blackball, on the West Coast, South Island. Seven sites in the Reefton area were sampled from April 2006 - February 2007 to establish changes over time in benthic algal communities of AMD and reference streams. Longitudinal change and ecosystem recovery were also investigated by sampling eight sites down Devils Creek, Reefton, and two of its tributaries. AMD has negative impacts on algal diversity, generally increases the dominance of certain taxa and, where metal oxide deposition or hydraulic disturbance are not great, can lead to algal proliferations. These proliferations were chlorophyte dominated, predominantly by filamentous Klebsormidium acidophilum. From the general survey a total of 15 taxa were identified from the most severely impacted sites (pH <3.6), which included both acidophiles and acidotolerant algae. Multivariate analyses strongly suggest that pH was the dominant factor controlling taxonomic occurrence of diatoms, macroalgae and the structure of the total assemblage. Other factors such as conductivity, metal oxide deposition, temperature, depth, month, geographic location and altitude were also important. Algal communities changed over time and this became more marked as AMD impact decreased. This was presumably due to AMD stressors reducing diversity, and thus the available scope for assemblage change. Longitudinal differences in assemblage structure within Devils Creek appeared to be in response to dilution of AMD in upper reaches and to changes in natural physical features such as gradient in mid and lower reaches. After a distance of 7.2 km the physicochemical effects of AMD and suspended clay inputs were minimal. At this site and at several previous sites, the assemblage exhibited a degree of recovery towards that found at unimpacted sites. A range of algae found in the broad scale-survey are potentially useful 'sensitive' indicators. These included: Heteroleibleinia purpurascens; Achnanthes oblongella; Oedogonium sp. and Spirogyra sp. In contrast: Euglena mutabilis; Navicula cincta; K. acidophilum; Microspora quadrata and Microthamnion kuetzingianum may be useful 'tolerance' indicators. These data show that AMD has a range of negative impacts on algae, and algae may be a useful tool for monitoring these impacts in West Coast streams.

Thesis (M.S.)--Western Washington University, 2009. / Includes bibliographical references (leaves 44-47). Also issued online.

Thesis (M. Sc.)--University of Canterbury, 2003. / Typescript (photocopy). Includes bibliographical references (leaves 104-110). Also available via the World Wide Web