Effet de l'aération d'appoint, de la saison et de l'espèce de macrophytes dans le traitement d'un effluent piscicole par marais artificiel

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Freshwater Resource Supply Modeling for Developed and Undeveloped Watersheds

Globally, the current state of freshwater resource management is insufficient and impeding the chance at a sustainable future. Human interference within the natural hydrologic cycle is becoming dangerously irreversible and the need to redefine resource managerial approaches is imminent. This research involves the development of a coupled natural-human freshwater resource supply model using a System Dynamics approach. The model was applied to two case studies, Somalia, Africa and the Phoenix Active Management Area in Arizona, USA. It is suggested that System Dynamic modeling would be an invaluable tool for achieving sustainable freshwater resource management in individual watersheds. Through a series of thought experiments, a thorough understanding of the systems’ dynamic behaviors is obtainable for freshwater resource managers and policy-makers to examine various courses of action for alleviating freshwater supply concerns. This thesis reviews the model, its development and an analysis of several thought experiments applied to the case studies.

The effect of a reduction of nitrogen and phosphorus to eutrophic and mesotrophic conditions towards silver nanoparticle (AgNP) on freshwater green algae species

We investigated the sensitivity of algae towards silver nanoparticles with OECD test medium and lower nutrient concentrations under standard test conditions to improve comparability and to exclude any other confounding factor aside nutrient levels. Two unicellular freshwater microalgae Desmodesmus subspicatus and Raphidocelis subcapitata were chosen due to their status as standard test organisms for the algae growth inhibition test and the response to changes in nutrient supply was compared. The original medium was used as the reference (standard). For the other four media, the amount of either nitrogen or phosphorus in the medium was lowered from half (50%) to one-fourth (25 %) of that of the OECD guideline, resulting in the following media: 50% N, 25% N, 50% P and 25% P medium. As test substance, the OECD reference material NM-300K was used. For this reason, the characterization of AgNP was done using DLS and Absorption spectra (UV/vis). Actual silver concentrations and ionic silver concentrations were measured at the highest test concentration used (100 µg Ag L-1) in R. subcapitata treatments only to reduce the number of samples. All tests were run according to the OECD guideline 201 with sterilized 50 mL cell culture flask. Each medium was tested using the test conditions for culturing with 3 replicates. Test concentrations for both algae species were 0, 25, 50 and 100 µg Ag L-1 for OECD, 50% P and 25% P while for both N reductions, the silver concentrations were 0, 10, 25 and 100 µg Ag L-1. Samples for determining the algal density were taken at every 24 h.

Benthic freshwater diatom abundance in streams and seepage areas of northern James Ross Island between 2004-2009

Background and aim - The non-marine diatom communities in the Antarctic Region are characterized by a typical species composition, in close relationship with their environment. Despite the growing interest, the diatom flora of James Ross Island is only poorly known. The present paper discusses the diversity of limnoterrestrial diatoms on this island: seepages and streams. Methods - The diatom flora of 53 samples taken on the eastern side of the Ulu peninsula on James Ross Island has been studied using light and scanning electron microscopy. Key results - A total of 69 diatom taxa belonging to 26 genera have been observed. The genera Luticola, Diadesmis, Muelleria and Pinnularia dominated the species composition. The flora shows an interesting mixture of cosmopolitan and Antarctic species containing several species reaching on James Ross Island their most northern distribution in the Antarctic Region. The taxonomical position of one widespread Antarctic species, Psammothidium papilio (D.E.Kellogg, Stuiver, T.B.Kellogg & Denton) Kopalova & Van de Vijver comb. nov., is corrected. Conclusions - The limnoterrestrial diatom flora of James Ross Island has a rather low number of species, of which a large proportion shows a restricted Antarctic distribution.

Intraspecific Behavioural Diversity in a Freshwater Zooplankton: A study of the fitness consequences of vertical migration behaviour for distinct morphs of Daphnia pulicaria

The literature on niche separation and coexistence between species is large, but there is widespread variation in behavioural strategy between individuals of the same species that has received much less attention. Understanding what maintains this diversity is important because intraspecific behavioural diversity can affect population dynamics and community interactions. Multiple behavioural strategies can arise either as phenotype-dependent ‘conditional strategies’, where phenotypic variation causes individuals to adopt different strategies for optimizing fitness, or as internally-independent ‘alternative strategies’, where multiple fitness peaks exist for individuals and strategic ‘choice’ remains plastic. Though intraspecific variation in stable phenotypes is known to maintain intraspecific behavioural diversity through conditional strategies, when internal conditions are highly plastic or reversible, it is not clear whether individual behaviours are maintained as conditional strategies, or as alternative strategies of equal fitness. In this study, I combine an observational and experimental approach to identify the likely mechanisms maintaining behavioural diversity between hemoglobin-rich and hemoglobin-poor morphs in a natural population of Daphnia pulicaria. In Round Lake, individuals with low hemoglobin migrate daily from the hypolimnion to the epilimnion, whereas individuals with high hemoglobin remain in the hypolimnion. Using high-resolution depth and time sampling, I discovered behavioural diversity both within and among hemoglobin phenotypes. I tested the role of hemoglobin phenotype in maintaining behavioural diversity using automated migration robots that move individuals across the natural environmental gradients in the lake. By measuring the fitness of each morph undergoing either a natural migration behaviour, or the migration of the opposite morph, I found that the fitness of hemoglobin rich and poor morphs in their natural behaviour does not differ, but that Hb-rich individuals can obtain equal fitness from either behaviour, while Hb-poor morphs suffer substantial drops in survivorship in the alternate migration behaviour. Thus, migration behaviour in this system exists as a conditional strategy for some individuals, and as alternative strategies of equal fitness for others. The results of this study suggest that individual limits in the expression of highly flexible internal conditions can reinforce intraspecific behavioural diversity. Few studies have measured the fitness consequences of switching migration strategies and this study provides a rare example in the field.

Detection of Human Enteric Viruses in Freshwater from European Countries

The transmission of water-borne pathogens typically occurs by a faecal–oral route, through inhalation of aerosols, or by direct or indirect contact with contaminated water. Previous molecular-based studies have identified viral particles of zoonotic and human nature in surface waters. Contaminated water can lead to human health issues, and the development of rapid methods for the detection of pathogenic microorganisms is a valuable tool for the prevention of their spread. The aims of this work were to determine the presence and identity of representative human pathogenic enteric viruses in water samples from six European countries by quantitative polymerase chain reaction (q-PCR) and to develop two quantitative PCR methods for Adenovirus 41 and Mammalian Orthoreoviruses. A 2-year survey showed that Norovirus, Mammalian Orthoreovirus and Adenoviruses were the most frequently identified enteric viruses in the sampled surface waters. Although it was not possible to establish viability and infectivity of the viruses considered, the detectable presence of pathogenic viruses may represent a potential risk for human health. The methodology developed may aid in rapid detection of these pathogens for monitoring

Detection of Human Enteric Viruses in Freshwater from European Countries

The transmission of water-borne pathogens typically occurs by a faecal–oral route, through inhalation of aerosols, or by direct or indirect contact with contaminated water. Previous molecular-based studies have identified viral particles of zoonotic and human nature in surface waters. Contaminated water can lead to human health issues, and the development of rapid methods for the detection of pathogenic microorganisms is a valuable tool for the prevention of their spread. The aims of this work were to determine the presence and identity of representative human pathogenic enteric viruses in water samples from six European countries by quantitative polymerase chain reaction (q-PCR) and to develop two quantitative PCR methods for Adenovirus 41 and Mammalian Orthoreoviruses. A 2-year survey showed that Norovirus, Mammalian Orthoreovirus and Adenoviruses were the most frequently identified enteric viruses in the sampled surface waters. Although it was not possible to establish viability and infectivity of the viruses considered, the detectable presence of pathogenic viruses may represent a potential risk for human health. The methodology developed may aid in rapid detection of these pathogens for monitoring

Development of release methods for critically endangered freshwater pearl mussels (Margaritifera margaritifera)

Biodiversity loss is a global problem with freshwater bivalves considered amongst the most
endangered biota. The freshwater pearl mussel, Margaritifera margaritifera, is declining
throughout its range owing to habitat degradation and overexploitation. In most of its range,
populations are regarded as reproductively non-functional which has led to the development
of captive breeding programmes. A novel method of releasing M. margaritifera was trialled,
with captive-bred juveniles being released into the rivers caged in ‘mussels silos’ (protective
concrete domes with ventilation creating upwelling to ensure water through flow). We
released 240 juvenile mussels and survival and growth rates were monitored for 18 months
post-release for three size classes: A (13.01-20.00mm); B (10.01-13.00mm); and C (4.01-
10.00mm). We explicitly tested two experimental treatments; one where sediment was added
to each silo (allowing mussels to orientate and burrow) and one without sediment. Survival
by the end of the experiment at month 18 was significantly higher for the largest size class at
97% (though growth was lowest in this cohort), and lowest for the smallest size class at 61%
(though growth was highest in this cohort). Survival and growth were unaffected by the
experimental treatment suggesting that adding sediment offered no advantage. Growth was
positively correlated with both water temperature and the particle size of suspended solids
(both of which were collinear, peaking in summer). There are a large number of ex situ
breeding programmes for freshwater pearl mussels throughout Europe and our finding
suggest that the use of ‘mussel silos’ could be a useful tool to protecting juvenile mussels
allowing them to be released at a relatively early stage of development, minimising the risk of
domestication.

Macroinvertebrate Diversity in Urban and Rural Ponds: Implications for Freshwater Biodiversity Conservation

Ponds are among the most biodiverse freshwater ecosystems, yet face significant threats from removal, habitat degradation and a lack of legislative protection globally. Information regarding the habitat quality and biodiversity of ponds across a range of land uses is vital for the long term conservation and management of ecological resources. In this study we examine the biodiversity and conservation value of macroinvertebrates from 91 lowland ponds across 3 land use types (35 floodplain meadow, 15 arable and 41 urban ponds). A total of 224 macroinvertebrate taxa were recorded across all ponds, with urban ponds and floodplain ponds supporting a greater richness than arable ponds at the landscape scale. However, at the alpha scale, urban ponds supported lower faunal diversity (mean: 22 taxa) than floodplain (mean: 32 taxa) or arable ponds (mean: 30 taxa). Floodplain ponds were found to support taxonomically distinct communities compared to arable and urban ponds. A total of 13 macroinvertebrate taxa with a national conservation designation were recorded across the study area and 12 ponds (11 floodplain and 1 arable pond) supported assemblages of high or very high conservation value. Pond conservation currently relies on the designation of individual ponds based on very high biodiversity or the presence of taxa with specific conservation designations. However, this site specific approach fails to acknowledge the contribution of ponds to freshwater biodiversity at the landscape scale. Ponds are highly appropriate sites outside of protected areas (urban/arable), with which the general public are already familiar, for local and landscape scale conservation of freshwater habitats.

Indigenous Māori values and perspectives to inform freshwater management in Aotearoa-New Zealand

In response to widespread water quality and quantity issues, the New Zealand Government has recently embarked on a number of comprehensive freshwater management reforms, developing a raft of national discussion and policy documents such as “Freshwater Reform 2013 and Beyond” and a National Policy Statement for freshwater management (NPS-FM 2014). Recent resource management reforms and amendments (RMA 2014), based on previous overarching resource management legislation (RMA 1991), set out a new approach and pathway to manage freshwater nationwide. Internationally, there is an increasing trend to engage with indigenous communities for research and collaboration, including indigenous groups as active participants in resource management decision making. What is driving this change toward more engagement and collaboration with indigenous communities is different for each country, and we document the progress and innovation made in this area in New Zealand. The indigenous rights of Māori in New Zealand are stated in the 1840 Treaty of Waitangi and in many forms of New Zealand's legislation. Local and central governments are eager to include local indigenous Māori groups (iwi/hapū) in freshwater management planning processes through meaningful engagement and collaboration. Key to the success of collaborative planning processes for Māori are enduring relationships between local government and Māori, along with adequate resourcing for all partners contributing to the collaborative process. A large number of shared governance and management models for natural resource management have emerged in New Zealand over the past 20 years, and some recent examples are reviewed. We provide some discussion to improve understanding and use of the terms used in these management models such as cogovernance, comanagement, and coplanning, and describe some of the more important frameworks and tools being developed with Māori groups (e.g., iwi/hapū), to strengthen Māori capacity in freshwater management and to support good collaborative process and planning.

Community perceptions of collaborative processes for managing freshwater resources

Six of New Zealand’s 16 regional councils are trialling collaborative planning as a means of addressing complex challenges in freshwater management. Although some work has been undertaken to evaluate similarities and differences across those processes, the success or failure rests with the public’s acceptance of the processes and their outcomes. This is the first study to evaluate public perceptions of freshwater management in regions with collaborative processes. We surveyed 450 respondents in Hawke’s Bay, Northland, and Waikato, some of whom live in catchments in which collaborative processes are under way and some of whom do not. In addition to assessing awareness of the collaborative planning processes, the survey measured perceptions regarding the regional council’s management of freshwater resources, the extent of agreement regarding freshwater management among various interests, the fairness of freshwater management, and the extent to which respondents believe that their interests and concerns are included in freshwater management. We hypothesized that relative to respondents in parts of the region in which traditional processes are in places, respondents in catchments with collaborative management of freshwater resources would have more positive perceptions of management, agreement, fairness, and interests, even if there is low awareness that a collaborative planning process is under way. Survey results indicate that knowledge of collaborative processes is generally low and that living in catchments with collaborative processes does not impact respondents’ perceptions of management, agreement, fairness, or interests in Northland or Waikato. However, relative to Hawke’s Bay respondents living outside of the collaborative catchment, respondents living inside the collaborative catchment believe that the regional council’s freshwater management is better and fairer. Moreover, Hawke’s Bay residents living inside the collaborative catchment perceive less conflict over freshwater management than Hawke’s Bay respondents living outside the collaborative catchment. Further research is needed to identify the reasons for this regional variation.

Sub lethal mercuric chloride toxicity induced stress related alterations in the epithelial lining of foot of the freshwater mussel Lamellidens marginalis (Lamarck)

Sub lethal (0.2 ppm) mercuric chloride induced stress related histopathological alterations in the epithelial linings of foot (podium) of the edible freshwater mussel Lamellidens marginalis (Lamarck) were studied using histochemical techniques up to 60 days of exposure. The histomorphological changes were manifested only slowly and its intensity was somewhat proportional to the duration of exposure. The immediate response of the exposed mussels was the altered mucous secretion. There was a progressive incorporation of sulphated glycoproteins into the secretory contents of the mucous cells especially in the first half of the experiment. Marked histopathological changes including necrosis, appearance of pyknotic nuclei, sloughing of epithelial cells and appearance of non-tissue spaces, etc., started appearing during the later half of the experiment. The fag end of the experiment, which witnessed prominent histomorphological changes, was accompanied by highly decreased mucous secretion. KEYWORDS: heavy metal toxicity, mercuric chloride, Lamellidens marginalis, freshwater mussel, histopathology.

A mesocosm analytical study on the impact of freshwater mussel (Lamellidens marginalis Lamarck) mediated bioturbation and biodeposition on some ecological factors of a freshwater lake

The biotic potential of the benthic filter feeding freshwater bivalve mollusc Lamellidens marginalis (Lamarck) influencing the nutrient dynamics of the bottom sediments of the lake by means of biodeposition and bioturbation activities were analysed using a lake mesocosm experiment. Five control as well as experimental mesocosms was maintained up to 60 days (d). The factors studied included the percentage of water content of the sediment, percentage of total nitrogen, percentage of organic matter along with the total phosphorus and humic acid content. While total phosphorus and humic acid content of the experimental mesocosoms showed gradual and significant increases from 30d of the experiment to reach the maximum levels after 60d, the percentage of organic matter registered significant increases right from 15d onwards and reached the maximum values after 60d. On the other hand, while the percentage of water content of the sediments of the experimental mesocosoms increased only up to 30d experiment, percentage of nitrogen was increased during the first half and at the fag end of the experiment. All the investigated ecological factors were found to be significantly influenced by the presence of L. marginalis in the experimental mesocosms. The study indicated that the mussel influence the nutrient dynamics of the inhabitant ecosystem through the processes of excretion, biodeposition of pseudofaeces and faeces, along with the bioturbation of the sediments brought about by their ploughing movements. KEYWORDS: freshwater mussel, Lamellidens marginalis, bioturbation, biodeposition, mesocosms.