Assessment of aquatic plant selection by waterfowl has been conducted during the winters of 1997-2000 on 49 0.2-0.79 ha research ponds in north central Texas. Ponds were categorized by dominant plant species into eight habitat types. Census with waterfowl species identification were performed to investigate impacts of aquatic vegetation and water depth on waterfowl. Eighteen waterfowl species were observed. Peak migration occurred in late December/early January. Mixed native ponds and mixed native/hydrilla ponds were the most frequently selected habitat types. The study included correlation analysis between pond water levels and waterfowl use. Full ponds received greatest use followed by half full ponds, while almost empty ponds received minimal use. Time activity budgets were conducted on waterfowl utilizing mixed native and hydrilla ponds to compare waterfowl time partitioning on native aquatic vegetation versus hydrilla. Although only minor differences were found in time budgets, social status appears to be strongly related to habitat selection. Ducks on native ponds were paired (86%), conversely no ducks on hydrilla ponds were paired. Hydrilla pond although frequently utilized, were populated by lower status birds mostly single hens.

The purpose of this study was to compare the environmental literacy of 11th and 12th graders who participated in an eighteen-week environmental education program using trade books versus 11th- and 12th-graders who participated in an eighteen-week, traditional environmental education program without the use of trade books. This study was conducted using a quasi-experimental research technique. Four high school aquatic science classes at two suburban high schools were used in the research. One teacher at each high school taught one control class and one experimental class of aquatic science. In the experimental classes, four trade books were read to the classes during the eighteen-week semester. These four books were selected by the participating teachers before the semester began. The books used were A Home by the Sea, Sea Otter Rescue, There's a Hair in My Dirt, and The Missing Gator of Gumbo Limbo. The instrument used to measure environmental literacy was the Children's Environmental Attitude and Knowledge Scale. This test was given at the beginning of the semester and at the end of the semester. The scores at the end of the semester were analyzed by 2 X 2 mixed model ANOVA with the teacher as the random effect and the condition (trade books) as the fixed effect. The statistical analysis of this study showed that the students in the experimental classes did not score higher than the control classes on the Children's Environmental Attitude and Knowledge Scale or on a subset of "water" questions. Several limitations were placed on this research. These limitations included the following: (1) a small number of classes and a small number of teachers, (2) change from the original plan of using environmental science classes to aquatic science classes, (3) possible indifference of the students, and (4) restrictive teaching strategies of the teachers.

The priming effect (PE), characterized as the enhanced microbial processing of bio-recalcitrant organic matter with the addition of labile substrates, has been hypothesized to moderate carbon (C) cycling in aquatic systems. In this study, aquatic PEs were evaluated through bacterial respiration and dissolved organic C consumption in incubations of water collected from three locations along the York River estuary. Incubations from White’s Landing on the Pamunkey River, a tidal freshwater tributary of the York, and from Croaker Landing in the middle of the estuary, displayed positive PEs when amended with labile C. In contrast, amended incubations from Gloucester Point, near the mouth of the estuary, displayed negative PEs, or reduced relative C metabolism, based on our calculations, This study provides empirical evidence for the occurrence of aquatic PEs and serves to elucidate how they may enhance or retard the processing and mineralization of organic C during transport to the ocean.

La connexion entre milieux aquatiques et terrestres a suscité l’intérêt de la communauté scientifique, notamment l’effet du transfert d’énergie et de matière sur le fonctionnement des écosystèmes adjacents. Beaucoup d’études se sont intéressées aux apports d’insectes aquatiques ailés dans les écosystèmes naturels, mais peu à leur impact en milieu agricole. En modifiant la production secondaire d’invertébrés aquatiques, les pratiques agricoles sont à même d’intensifier ou diminuer l’effet de ces apports aquatiques dans les terres agricoles et par conséquent la fourniture de services écosystémiques utiles à l’agriculture. Nous avons collecté des données d’émergences et de dispersion d’insectes aquatiques depuis plusieurs rivières dans des paysages agricoles. Les principaux groupes d’insectes émergents sont les trichoptères (56%), chironomidés (25%) et éphéméroptères (19%). Nous estimons la biomasse sèche émergente entre 1445 et 7374 mg m-2 an-1 selon les sites. Une majorité de ces insectes aquatiques se déposent sur une bande entre 0 et 10 mètres du bord de la rivière mais une proportion importante (45%) se dépose dans les cultures après 20 mètres. Nous apportons de nouvelles et prometteuses connaissances suggérant que les insectes aquatiques participent à la fourniture de plusieurs services écosystémiques (fertilisation, contrôle biologie, épuration de l’eau et pollinisation). En paysage agricole, une communauté d’insectes riche et abondant est nécessaire à la mise en place d’un système agricole durable. Nous pensons que le rôle des insectes aquatiques est à ce titre important et suggérons de nouvelles pistes de recherches pour l’agroécologie. / The connection between aquatic and terrestrial habitats has increased scientific interest in ecological subsidies, focusing on how the transfer of matter and energy between adjacent ecosystems can modify the ecosystems functioning. Much attention has focused on aquatic subsidies associated with winged aquatic insects in pristine areas, but their implication in agricultural landscapes is rarely considered. By altering the production of benthic macroinvertebrates, agricultural practices can increase or decrease the strength of aquatic subsidies and subsequently the provision of several ecosystem services to agriculture. We have monitored the emergence and inland dispersal of adult aquatic insects from several agricultural streams. Most emerging dry mass (DM) belong to Trichoptera (56%), Chironomidae (25%) and Ephemeroptera (19%). We estimate that annual emerging dry mass of aquatic insects ranged between 1445 and 7374 mg m-2 y-1 depending on stream. The majority of aquatic insects emerging falls between 0 and 10 meters from stream hedges. However, a great proportion (45%) though disperses and eventually falls after 20 meters from the stream. We provide new and promising evidence suggesting that winged stream insects can support several ecosystem services (soil fertilization, crop pest control, water purification and pollination). In agricultural landscapes, a rich and abundant insect community is necessary to promote sustainable practices, and we believe the role of aquatic subsidies in providing ecosystem services to agriculture is a new and promising field of research in agroecology.

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Diversos estudos têm relatado incrementos na força muscular a partir de treinamentos com diferentes metodologias no meio aquático. No entanto, não foram encontradas abordagens sobre a utilização de séries únicas e múltiplas no treinamento de força no meio aquático. O objetivo do presente estudo foi comparar os incrementos na força muscular dinâmica máxima, na força de resistência e na força de potência em mulheres jovens e sedentárias, submetidas ao treinamento de força no meio aquático, com diferentes volumes de treinamento. Sessenta e seis mulheres jovens e saudáveis (24,72±4,33 anos) foram aleatoriamente divididas em dois grupos: Série Simples (1S) e Séries Múltiplas (3S), durante a primeira etapa do treinamento, composta por 10 semanas. Após este período, sessenta mulheres continuaram o treinamento por mais um período de dez semanas e foram aleatoriamente sub-divididas em quatro grupos de estudo: simples/simples (SS), simples/múltipla (SM), múltipla/simples (MS) e múltipla/múltipla (MM). Todos os grupos realizaram duas sessões semanais durante as 20 semanas, sendo que os exercícios foram executados em máxima velocidade por trinta segundos e foram realizados em forma de circuito, com intervalo de dois a três minutos entre cada grupo muscular. Foram realizadas avaliações nas etapas pré-treinamento, após 10 semanas e após 20 semanas de treinamento. Foram realizadas avaliações de uma repetição máxima (1RM) e de Repetições Máximas com 60% de 1RM nos exercícios supino, rosca bíceps, flexão de joelhos e extensão de joelhos. Além destas, foram realizadas avaliações de força potente por meio dos saltos Squat Jump e Countermovement Jump. Os resultados foram analizados utilizando ANOVA para medidas repetidas com fator grupo ( =0,05). Ao longo das primeiras dez semanas de treinamento, ambos os grupos (1S e 3S) apresentaram incrementos na força muscular dinâmica máxima, na força resistente e na força potente sem diferença entre os grupos (p>0,05). Nesta etapa os incrementos percentuais na força máxima para o grupo 1S foram de 9,72±9,54% a 18,82±11,17%; no grupo 3S foram de 10,49±9,99% a 18,48±11,07%. Na força resistente os incrementos no grupo 1S foram de 19,45±15,24% a 38,01±26,50%; no grupo 3S foram de 13,04±11,25% a 51,01±36,07%. Na força potente os incrementos no grupo 1S foram de 10,90±13,68% (SJ) e 9,09±8,01% (CMJ); no grupo 3S foram de 8,25±11,67% (SJ) e 6,78±6,83% (CMJ). Após vinte semanas de treinamento, todos os grupos de estudo demonstraram incremento na força muscular dinâmica máxima, na força resistente e na força potente, sem diferença significativa entre os grupos, ou seja, mesmo com a manutenção, o aumento ou a diminuição do número de séries, observou-se o mesmo comportamento da força muscular. Na força máxima os incrementos para o grupo SS foi de 16,53±9,81% a 30,93±11,65%; no grupo SM foi de 15,41±12,77% a 28,87±15,11%; no grupo MS foi de 17,12±13,02% a 28,04±12,95%; no grupo MM foi de 20,98±13,60% a 26,53±13,17%. Na força resistente, os incrementos para o grupo SS foram de 18,32±25,57% a 46,65±49,04%; no grupo SM foram de 13,99±14,50% a 42,50±20,49%; no grupo MS foram de 13,26±23,03 a 48,24±46,50%; no grupo MM foram de 14,14±28,54% a 59,62±43,59%. Na força potente, os incrementos no grupo SS foram de 12,60±12,13% (SJ) e 11,28±10,62% (CMJ); no grupo SM foram de 21,17±17,83% (SJ) e 4,75±7,25% (CMJ); no grupo MS foram de 12,43±13,67% (SJ) e de 5,74±6,63% (CMJ); no grupo MM foram de 18,67±26,18% (SJ) e de 8,83±4,71% (CMJ). Ao final do estudo, pode-se concluir que mulheres jovens e sedentárias apresentaram melhora na força muscular dinâmica máxima, na força de resistência e na força de potência após 20 semanas de treinamento, independente do volume de treinamento realizado. / Several studies have shown significant increase in the muscle strength induced by different exercise trainings protocols in aquatic environment. However, no studies were found investigating the adaptations of single and multiple sets during the resistance training in aquatic environment. Thus, the aim of the present study was to compare the effects between two aquatic resistance training (single and multiple sets) on maximal dynamic muscle strength, muscle endurance and muscle power in untrained women. Sixty-six young women (24.72±4.33 years) were randomly placed into two groups: single set (1S) and multiple set (3S) during the first 10 weeks. After that, sixty women maintained the training by an additional 10 weeks and were randomly sub-divided in four experimental groups: single/single (SS), single/multiple (SM), multiple/single (MS), multiple/multiple (MM). The subjects performed the aquatic resistance training during 20 weeks twice a week, and the exercises were performed in circuit form with 2-3 min of recovery among each muscular group. The one repetition maximal test (1RM), muscle endurance test (maximal repetitions at 60% 1RM) and muscle power test (squat and counter movement jump performance) were evaluated at pre, middle and post training. The results were analyzed using repeated measures ANOVA (factor: group), and when applicable, Bonferroni post-hoc test was used ( =0.05). After the first 10 weeks of training, there were increases in maximal dynamic muscle strength, muscle endurance and muscle power in both 1S and 3S, with no difference between the groups. The relative gains in the first 10 weeks for the maximal strength in the 1S ranged from 9.72±9.54% to 18.82±11.17%, and in the 3S ranged from 10.49±9.99% to 18.48±11.07% in the different exercises. The muscle endurance relative gains in the 1S ranged from 19.45±15.24% to 38.01±26.50%, and in the 3S ranged from 13.04±11.25% to 51.01±36.07% in the different exercises. In addition, the muscular power relative gains in the 1S was 10.90±13.68% in Squat Jump and 9.09±8.01% in Counter Movement Jump. The same pattern was found in the 3S, with relative gain of 8.25±11.67% in the Squat Jump and 6.78±6.83% in the Counter Movement Jump. After the 20 weeks of training, both groups showed increases on maximal dynamic in the muscle strength, on muscle endurance, and, on muscle power with no differences among the groups. Thus, even maintaining, increasing or decreasing the number of sets, there were no differences in muscle strength performance. The maximal strength gains ranged from 16.53±9.81% to 30.93±11.65% in the SS group; from 15.41±12.77% to 28.87±15.11% in the SM group; from 17.12±13.02% to 28.04±12.95%; in the MS group; and, from 20.98±13.60% to 26.53±13.17% in the MM group. The muscle endurance relative gains raged from 18.32±25.57% to 46.65±49.04% in the SS group; from 13.99±14.50% to 42.50±20.49% in the SM group; from 13.26±23.03 to 48.24±46.50% in the MS group; and, from 14.14±28.54% a 59.62±43.59% in the MM group. Moreover, the muscle power gains were 12.60±12.13% in the SJ and 11.28±10.62% in the CMJ in the SS group; 21.17±17.83% in the SJ and in the 4.75±7.25% CMJ in the SM group; 12.43±13.67% in the SJ and 5.74±6.63% in the CMJ in the MS group; and, 18.67±26.18% in the SJ and 8.83±4,71% in the CMJ in the MM. In conclusion, untrained young women presented a improvements in maximal dynamic muscle strength, muscle endurance and muscle power after 20 weeks of aquatic resistance training, independent of the training volume performed.

Research into the polyculture of finfish and crayfish has been conducted in Western Australia for over a decade now. This research was instigated out of a need to increase revenues from freshwater crayfish farmers wishing to diversify their income base with a view to increasing profitability and reducing risk. It has become clear that several key variables dictate how the polyculture system (i.e. polysystem) will perform. These include biological factors like: size of participating species, relative densities, gender, planktonic turbidity, natural feeds; and abiotic factors like: light intensity, clay turbidity, floating cages for segregation, water quality, and habitat/shelter complexity. Many of these factors can be controlled / adjusted by the manager of the polysystem to maximise performance, production and profitability.While much of the research to date has focussed on the marron (Cherax tenuimanus) industry, it is also important to realise that an understanding of these factors can also assist other crayfish polysystems, like integrated agri-aquaculture systems containing yabbies (Cherax albidus). Some of the factors that influence how the system will perform may become more prevalent, like suspended clay turbidity and the associated role of light intensity in species interactions, or shelter complexity and the resulting choice of shelter material. But overall, they are the same basic variables and we must understand how they affect the particular multi-species system that we are dealing with. There is a lot to be learned from the literature on how these variables affect multi-species aquatic environments in the wild. Perhaps aquaculturists have not considered this enough in the past. Some farmers seem to believe that these variables are different JUST because it is a culture system. This is not true. / The variables will take on different levels in a culture system (i.e. a manager will stimulate turbidity, provide artificial feeds, stock different sizes, and supply particular types of shelter) BUT the actual variables themselves (e.g. food, density, light, shelter) are basic to ALL aquatic ecosystems. Other researchers have looked at important factors like density, gender, and light intensity / turbidity in crayfish polysystems - but the issue of habitat complexity and the role of shelter has not been adequately addressed. This thesis will investigate some basic questions about shelter and endeavour to apply them to crayfish polysystems, with the emphasis on marron (C. tenuimanus) and yabbies (C. albidus) because these are the two most commercially important species of crayfish in Western Australia. Importantly, it should be noted that due to the invasive nature of yabbies, and their apparent ability to displace native marron in the wild, findings will be related to yabby-marron competition / displacement where relevant. We need to know many things about shelter: what type is best in a multi-species system? Should the shelter size match the crayfish size? Do marron have different requirements for shelter than yabbies? Does it matter who gets first use of a shelter (i.e. prior residence effect)? Can we learn about crayfish shelter requirements by examining the behaviour / plasticity of crayfish species? If crayfish are stocked with finfish and they retreat into shelter as a predator-avoidance measure, is the complexity important given that their densities will be higher? If densities of crayfish inside shelters are higher in polysystems, will cannibalism be a concern, particularly when conditions are right for moulting? Does visual recognition and / or chemo-detection of a predator affect the shelter usage by marron or yabbies? / Does temperature affect shelter usage behaviour for a burrowing species like yabbies? Shelter is an important factor in the life history of a freshwater crayfish and an understanding of its influence on different species is important for maximising system performance. Crayfish are categorised depending on their ability to construct shelters (i.e. burrows). Yabbies have evolved in systems with fluctuating water quality and many predators and, as such, have learned to burrow (to escape drought and also to escape predators). Marron, on the other hand, are a non-burrowing native crayfish species that have existed with relatively few predators in the South-West. As a result, marron are less capable of modifying their behaviour when confronted with a predator (i.e. low behavioural plasticity). Species with high plasticity, like yabbies, are more capable of adapting to new environments, because they can change their behaviour to increase their chance of survival. Therefore we can expect yabbies and marron to utilize habitats differently and we should compare these behaviours as a basis to developing management strategies. This type of knowledge may also assist with managing the translocation and spread of yabbies in the wild and their displacement of native marron.Within multi-species systems, the physical structure of shelter plays an important role inprotecting crayfish and the perfect shelter would not only provide safety from co-stocked finfish, but also from conspecific cannibalism. Given the different life histories and behaviours, it is probable that both species of crayfish will have different refuge requirements.Over the course of this four-year investigation, trials were conducted in four culture systems (72L aquariums, 300L circular tanks, 80t mesocosm tank, and 720m2 earthen ponds) using marron and yabbies as the species of interest. / Silver perch and Murray cod were chosen as the finfish species of interest as they appear to have the highest aquaculture potential for native freshwater finfish in Australia at the present time. Further, both of these fish have been documented as potential predators of crayfish, resulting in a challenge to understand the role of shelter in minimising the negative effects of fish-crayfish interactions within a polysystem. This study has confirmed that shelter plays a critical role in multi-species system dynamics. In the case of polysystems, it will affect both interspecific and intra-specific interactions, ultimately governing production and profitability, along with the other, previously defined factors. This means that the manager of a polysystem can influenceproductivity by understanding: a) the behavioural characteristics and biology of the crayfish; b) the feeding biology of the finfish; and c) the system variables (both biotic and abiotic) that will affect the overall well being of the fish and crayfish. In the case ofshelter, the manager should understand the available shelter types, the appropriatedensities, the importance of matching complexity to the crayfish size, and the prior residence effect when choosing a timing strategy for stocking and harvesting. Prior residence increased resource holding potential for both marron and yabbies in the short term. In fact, prior residence was a stronger determinant of successful sheltering than crayfish gender or species. However, in longer-term trials the physical size of the crayfish (larger animals evicted smaller animals) and reproductive status (berried females were successful at evicting all other crayfish) were more important factors in determining successful shelter acquisition, although the temporal variations (i.e. growth and release of young) complicate the issue. / When stocking crayfish of different sizes, and in polysystems, the correct size of shelter becomes critical, as smaller individuals will be forced to leave over-sized shelter and locate a shelter commensurate with their own body size to avoid predators. This is relevant to crayfish nurseries where complex habitat is paramount for juvenile cohorts that display variation in sizes and gender. The expansion of crayfish polyculture holds considerable promise; however, furtherinvestigations are required into shelter complexity within floating fish cages, shelter types and arrangement of shelters within ponds (for increased production and ease-of-harvesting), potential of yabbies in polyculture (comparison of monosex and hybrid strains), and the impact of shelter on escape behaviour of marron in a polysystem.

This thesis considers the implications of changes in the supply of resources for photosynthesis, with regard for modes of carbon acquisition employed by aquatic plants of the River Murray. Carbon supplies are inherently more variable for aquatic plants than for those in terrestrial environments, and variations are intensified for plants in semi-arid regions, where water may be limiting. In changeable environments the most successful species are likely to be those with flexible carbon-uptake mechanisms, able to accommodate variations in the supply of resources. Studies were made of plants associated with wetland habitats of the Murray, including Crassula helmsii, Potamogeton tricarinatus, P. crispus and Vallisneria americana. The aim was to elucidate the mechanisms of carbon uptake and assimilation employed, and to determine how flexibility in carbon uptake and/or assimilation physiology affect survival and distribution. Stable carbon isotopes were used to explore the dynamics of carbon uptake and assimilation, and fluorescence was used to identify pathways and photosynthetic capacity. The studies suggest that physiological flexibility is adaptive survival in changeable environments, but probably does not enhance the spread or dominance of these species. V. americana is a known bicarbonate-user, and it is shown here that it uses the Crassulacean Acid Metabolism (CAM) photosynthetic pathway under specific conditions (high light intensity near the leaf tips) concurrently with HCO[subscript]3 - uptake, while leaves deeper in the water continue to use the C[subscript]3 pathway, with CO₂ as the main carbon source. However, V. americana does not use CAM when under stress, such as exposure to high light and temperature. The diversity of carbon uptake and assimilation mechanisms in this species may explain its competitive ability in habitats associated with the Murray. In this way it is able to maximise use of light throughout the water column. In shallow, warm water, where leaves are parallel to the surface, CAM ability is likely to be induced along the length of the leaf, allowing maximal use of carbon and light. The amphibious C. helmsii is shown to use CAM on submergence, even where water levels fluctuate within 24 hours. This allows continued photosynthesis in habitats where level fluctuations prevent access to atmospheric CO₂. It appears that stable conditions are most favourable for growth and dispersal, and that the spread of C. helmsii is mainly by the aerial form. Carbon uptake by P. tricarinatus under field conditions is compared with that of P. crispus to demonstrate differences in productivity associated with aqueous bicarbonate and atmospheric CO₂ use. P. tricarinatus uses HCO[subscript]3 - uptake to promote growth toward the surface, so that CO₂ can be accessed by floating leaves. Atmospheric contact provides access to light and removes the limitation of aqueous diffusive resistance to CO₂, thereby increasing photosynthetic capacity above that provided by submerged leaves. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320380 / Thesis (Ph.D) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

Offprint of the author's journal article in pocket / Bibliography: leaves 162-193 / x, 193 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1986

Thesis (M. Sc.)--College of William and Mary. / Typescript (photocopy). Vita. Includes bibliographical references (leaves 73-87).