Marine soft bottom systems show a high variability across multiple spatial and temporal scales. Both natural and anthropogenic sources of disturbance act together in affecting benthic sedimentary characteristics and species distribution. The description of such spatial variability is required to understand the ecological processes behind them. However, in order to have a better estimate of spatial patterns, methods that take into account the complexity of the sedimentary system are required. This PhD thesis aims to give a significant contribution both in improving the methodological approaches to the study of biological variability in soft bottom habitats and in increasing the knowledge of the effect that different process (both natural and anthropogenic) could have on the benthic communities of a large area in the North Adriatic Sea. Beta diversity is a measure of the variability in species composition, and Whittaker’s index has become the most widely used measure of beta-diversity. However, application of the Whittaker index to soft bottom assemblages of the Adriatic Sea highlighted its sensitivity to rare species (species recorded in a single sample). This over-weighting of rare species induces biased estimates of the heterogeneity, thus it becomes difficult to compare assemblages containing a high proportion of rare species. In benthic communities, the unusual large number of rare species is frequently attributed to a combination of sampling errors and insufficient sampling effort. In order to reduce the influence of rare species on the measure of beta diversity, I have developed an alternative index based on simple probabilistic considerations. It turns out that this probability index is an ordinary Michaelis-Menten transformation of Whittaker's index but behaves more favourably when species heterogeneity increases. The suggested index therefore seems appropriate when comparing patterns of complexity in marine benthic assemblages. Although the new index makes an important contribution to the study of biodiversity in sedimentary environment, it remains to be seen which processes, and at what scales, influence benthic patterns. The ability to predict the effects of ecological phenomena on benthic fauna highly depends on both spatial and temporal scales of variation. Once defined, implicitly or explicitly, these scales influence the questions asked, the methodological approaches and the interpretation of results. Problem often arise when representative samples are not taken and results are over-generalized, as can happen when results from small-scale experiments are used for resource planning and management. Such issues, although globally recognized, are far from been resolved in the North Adriatic Sea. This area is potentially affected by both natural (e.g. river inflow, eutrophication) and anthropogenic (e.g. gas extraction, fish-trawling) sources of disturbance. Although few studies in this area aimed at understanding which of these processes mainly affect macrobenthos, these have been conducted at a small spatial scale, as they were designated to examine local changes in benthic communities or particular species. However, in order to better describe all the putative processes occurring in the entire area, a high sampling effort performed at a large spatial scale is required. The sedimentary environment of the western part of the Adriatic Sea was extensively studied in this thesis. I have described, in detail, spatial patterns both in terms of sedimentary characteristics and macrobenthic organisms and have suggested putative processes (natural or of human origin) that might affect the benthic environment of the entire area. In particular I have examined the effect of off shore gas platforms on benthic diversity and tested their effect over a background of natural spatial variability. The results obtained suggest that natural processes in the North Adriatic such as river outflow and euthrophication show an inter-annual variability that might have important consequences on benthic assemblages, affecting for example their spatial pattern moving away from the coast and along a North to South gradient. Depth-related factors, such as food supply, light, temperature and salinity play an important role in explaining large scale benthic spatial variability (i.e., affecting both the abundance patterns and beta diversity). Nonetheless, more locally, effects probably related to an organic enrichment or pollution from Po river input has been observed. All these processes, together with few human-induced sources of variability (e.g. fishing disturbance), have a higher effect on macrofauna distribution than any effect related to the presence of gas platforms. The main effect of gas platforms is restricted mainly to small spatial scales and related to a change in habitat complexity due to a natural dislodgement or structure cleaning of mussels that colonize their legs. The accumulation of mussels on the sediment reasonably affects benthic infauna composition. All the components of the study presented in this thesis highlight the need to carefully consider methodological aspects related to the study of sedimentary habitats. With particular regards to the North Adriatic Sea, a multi-scale analysis along natural and anthopogenic gradients was useful for detecting the influence of all the processes affecting the sedimentary environment. In the future, applying a similar approach may lead to an unambiguous assessment of the state of the benthic community in the North Adriatic Sea. Such assessment may be useful in understanding if any anthropogenic source of disturbance has a negative effect on the marine environment, and if so, planning sustainable strategies for a proper management of the affected area.

Lo scopo di questa tesi è quello di valutare l'effetto della salinizzazione dei suoli sugli invertebrati edafici. Nell'ambito di questo obiettivo generale sono state effettuate due distinte attività di ricerca: una indagine sul campo e una serie di esperimenti di laboratorio. Lo studio sul campo è stato condotto nella Pineta di San Vitale (Ravenna, Italia). L'obiettivo specifico è stato quello di valutare la qualità biologica dei suoli attraverso l'analisi del popolamento dei microartropodi edafici, in relazione alla diversità del suolo e in particolare alla salinizzazione. La qualità biologica dei suoli è stata valutata mediante l'indice QBS-ar. La Pineta è stata campionata nella zona Est, più colpita da intrusione salina e nella zona Ovest dove questo fenomeno è meno evidente. I campionamenti sono stati effettuati in primavera ed estate. I risultati confermano che le caratteristiche chimico-fisiche si modificano in base al gradiente sommità dunali-depressioni interdunali. Per quanto riguarda il popolamento dei microartropodi alcune caratteristiche sono comuni alla maggior parte delle stazioni con lo stesso pedotipo. Non è stato evidenziato alcuno stress sui popolamenti attribuibule alla salinizzazione. Nel complesso, i valori di QBS-ar sono piuttosto elevati. Gli esperimenti di laboratorio sono stati finalizzata alla valutazione degli effetti combinati della salinità del suolo e della contaminazione da pesticidi (chlorpyrifos) sul lombrico Eisenia andrei. Nel complesso, i risultati indicano che effetti avversi sui lombrichi sono possibili a livelli di salinizzazione dei suoli ancora compatibili a concentrazioni di chlorpyrifos che sono piuttosto alte in confronto con i tipici risultati di campo, ma ancora compatibili con l'uso consigliato. / The aim of this thesis is to evaluate the effect of soil salinization on terrestrial invertebrates. In the context of this general objective two distinct research activities were performed: a field survey and a series of laboratory experiments. The field study was conducted in the San Vitale Pinewood (Ravenna, Italy). The specific goal was to evaluate the biological quality of soils through the analysis of edaphic microarthropod assemblages, in relation to soil diversity and in particular to salinization. The biological quality of soils was assessed by the QBS-ar index. The Pinewood was sampled in the East zone, more affected by saline intrusion and in the West zone where this phenomenon is less conspicuous. The samplings were performed in spring and summer. The results confirm that soil chemical and physical characteristics changed according to the top-dunal – interdunal depression gradient. Regarding the microarthropod assemblages and the QBS-ar, some features were common to most stations with the same soil type. There was no evidence of stress due to salinization in the assemblages. Overall, QBS-ar was rather high. The laboratory experiments were aimed at the assessment of the interactive effects of soil salinity and pesticide contamination (chlorpyrifos) on the earthworm Eisenia andrei. As an overall, the results indicates that adverse effects on earthworms are possible at levels of soil salinization still compatible with agricultural land use and at chlorpyrifos concentrations that are rather high in comparison with typical field findings but still compatible with the recommended use. Salinity can affect exposure-response relationship of reproduction to chlorpyrifos.

Since large stretches of European coasts are already retreating and projected scenarios are worsening, many artificial structures, such as breakwaters and seawalls, are built as tool against coastal erosion. However artificial structures produce widespread changes that alter the coastal zones and affect the biological communities. My doctoral thesis analyses the consequences of different options for coastal protection, namely hard engineering ‘artificial defences’ (i.e. impact of human-made structures) and ‘no-defence’ (i.e. impact of seawater inundation). I investigated two new aspects of the potential impact of coastal defences. The first was the effect of artificial hard substrates on the fish communities structure. In particular I was interested to test if the differences among breakwaters and natural rocky reef would change depending on the nature of the surrounding habitat of the artificial structure (prevalent sandy rather than rocky). The second was the effect on the native natural sandy habitats of the organic detritus derived from hard-bottom species (green algae and mussels) detached from breakwaters. Furthermore, I investigated the ecological implication of the “no-defend” option, which allow the inundation of coastal habitats. The focus of this study was the potential effect of seawater intrusion on the degradation process of marine, salt-marsh and terrestrial detritus, including changes on the breakdown rates and the associated macrofauna. The PhD research was conducted in three areas along European coasts: North Adriatic sea, Sicilian coast and South-West England where different habitats (coastal, estuarine), biological communities (soft-bottom macro-benthos; rocky-coastal fishes; estuarine macro-invertebrates) and processes (organic enrichment; assemblage structure; leaf-litter breakdown) were analyzed. The research was carried out through manipulative and descriptive field-experiments in which specific hypothesis were tested by univariate and multivariate analyses.

Widespread occurrence of pharmaceuticals residues has been reported in aquatic ecosystems. However, their toxic effects on aquatic biota remain unclear. Generally, the acute toxicity has been assessed in laboratory experiments, while chronic toxicity studies have rarely been performed. Of importance appears also the assessment of mixture effects, since pharmaceuticals never occur in waters alone. The aim of the present work is to evaluate acute and chronic toxic response in the crustacean Daphnia magna exposed to single pharmaceuticals and mixtures. We tested fluoxetine, a SSRI widely prescribed as antidepressant, and propranolol, a non selective β-adrenergic receptor-blocking agent used to treat hypertension. Acute immobilization and chronic reproduction tests were performed according to OECD guidelines 202 and 211, respectively. Single chemicals were first tested separately. Toxicity of binary mixtures was then assessed using a fixed ratio experimental design with concentrations based on Toxic Units. The conceptual model of Concentration Addition was adopted in this study, as we assumed that the mixture effect mirrors the sum of the single substances for compounds having similar mode of action. The MixTox statistical method was applied to analyze the experimental results. Results showed a significant deviation from CA model that indicated antagonism between chemicals in both the acute and the chronic mixture tests. The study was integrated assessing the effects of fluoxetine on a battery of biomarkers. We wanted to evaluate the organism biological vulnerability caused by low concentrations of pharmaceutical occurring in the aquatic environment. We assessed the acetylcholinesterase and glutathione s-transferase enzymatic activities and the malondialdehyde production. No treatment induced significant alteration of biomarkers with respect to the control. Biological assays and the MixTox model application proved to be useful tools for pharmaceutical risk assessment. Although promising, the application of biomarkers in Daphnia magna needs further elucidation.

Climate-change related impacts, notably coastal erosion, inundation and flooding from sea level rise and storms, will increase in the coming decades enhancing the risks for coastal populations. Further recourse to coastal armoring and other engineered defenses to address risk reduction will exacerbate threats to coastal ecosystems. Alternatively, protection services provided by healthy ecosystems is emerging as a key element in climate adaptation and disaster risk management. I examined two distinct approaches to coastal defense on the base of their ecological and ecosystem conservation values. First, I analyzed the role of coastal ecosystems in providing services for hazard risk reduction. The value in wave attenuation of coral reefs was quantitatively demonstrated using a meta-analysis approach. Results indicate that coral reefs can provide wave attenuation comparable to hard engineering artificial defenses and at lower costs. Conservation and restoration of existing coral reefs are cost-effective management options for disaster risk reduction. Second, I evaluated the possibility to enhance the ecological value of artificial coastal defense structures (CDS) as habitats for marine communities. I documented the suitability of CDS to support native, ecologically relevant, habitat-forming canopy algae exploring the feasibility of enhancing CDS ecological value by promoting the growth of desired species. Juveniles of Cystoseira barbata can be successfully transplanted at both natural and artificial habitats and not affected by lack of surrounding adult algal individuals nor by substratum orientation. Transplantation success was limited by biotic disturbance from macrograzers on CDS compared to natural habitats. Future work should explore the reasons behind the different ecological functioning of artificial and natural habitats unraveling the factors and mechanisms that cause it. The comprehension of the functioning of systems associated with artificial habitats is the key to allow environmental managers to identify proper mitigation options and to forecast the impact of alternative coastal development plans.

Coral reefs are the most biodiverse ecosystems of the ocean and they provide notable ecosystem services. Nowadays, they are facing a number of local anthropogenic threats and environmental change is threatening their survivorship on a global scale. Large-scale monitoring is necessary to understand environmental changes and to perform useful conservation measurements. Governmental agencies are often underfunded and are not able of sustain the necessary spatial and temporal large-scale monitoring. To overcome the economic constrains, in some cases scientists can engage volunteers in environmental monitoring. Citizen Science enables the collection and analysis of scientific data at larger spatial and temporal scales than otherwise possible, addressing issues that are otherwise logistically or financially unfeasible. “STE: Scuba Tourism for the Environment” was a volunteer-based Red Sea coral reef biodiversity monitoring program. SCUBA divers and snorkelers were involved in the collection of data for 72 taxa, by completing survey questionnaires after their dives. In my thesis, I evaluated the reliability of the data collected by volunteers, comparing their questionnaires with those completed by professional scientists. Validation trials showed a sufficient level of reliability, indicating that non-specialists performed similarly to conservation volunteer divers on accurate transects. Using the data collected by volunteers, I developed a biodiversity index that revealed spatial trends across surveyed areas. The project results provided important feedbacks to the local authorities on the current health status of Red Sea coral reefs and on the effectiveness of the environmental management. I also analysed the spatial and temporal distribution of each surveyed taxa, identifying abundance trends related with anthropogenic impacts. Finally, I evaluated the effectiveness of the project to increase the environmental education of volunteers and showed that the participation in STEproject significantly increased both the knowledge on coral reef biology and ecology and the awareness of human behavioural impacts on the environment.

No description available.

Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of the degree of saturation (as well as its duration). Also the fraction of the total N2O that is actually emitted to the atmosphere depends heavily on the structure and wetness of the soil. The nitrous oxide dynamic is therefore a function of the antecedent wetness condition, the nutrient content of the peat-land, the physical characteristics of the peat-land and the vertical stratification of layers at different redox and oxygen condition, which may affect the annual N budget. In addition, the combined use of soil column and chamber experiments suggest a negative correlation between soil moisture and N2O in dynamic condition and a functional dependence of N2O emissions from the oxygen concentration. We found that the time scale of water dynamic was faster than the biological scale of trace gas emissions. Finally, the relationship of nitrous oxide versus water content was reproduced by using a lumped model which include oxygen dynamic. Preliminary results suggest that by accounting for oxygen dynamic, it is possible to reproduce the functional behavior observed in the experiment and that the latter is depending on the physical and biological properties of the soil. Keywords: water dynamics, nitrous oxide emissions, nitrate ammonification,feammox, denitrification, soil heterogeneity, oxygen, redox.

Forest management involves dealing with conflicts between the protection of nature and the use of natural resources. Bad management practices have led to significant forest degradation worldwide. It is estimated that globally about 13 million hectares of forest are lost every year, leading to a massive loss of biodiversity and other forest-related ecosystem services, such as soil stabilisation and watershed protection. This is particularly dangerous in poor regions, where livelihoods are strongly based on locally available natural resources. In 2000, IUCN and WWF have introduced a new restoration approach called Forest Landscape Restoration (FLR) that aims to regain ecological integrity and enhance human well-being in deforested or degraded forest landscapes. FLR goes well beyond planting trees: it is about re-designing the landscape mosaic in a way that both nature and people are benefited. To this purpose, different actions should be taken at different locations across the landscape. From a planning perspective, this calls for proper methods and tools that help identifying where to act and what to do. The present research aimed to contribute to this problem by developing and testing spatial decision tools to support the design of landscape mosaics. More specifically, the study had three main objectives. The first objective was the identification of criteria and indicators (C&I) for the prioritisation of forest restoration interventions. Knowing which areas are ecologically more suitable to host a restoration intervention is a prerequisite of any FLR-based plan. There can be areas where restoration is more urgent, areas where it is more likely to succeed and areas where it is expected to bring the highest ecological benefits. Unfortunately, a widely accepted framework for the prioritisation of forest restoration areas is lacking. This problem was addressed by conducting an expert survey to define a set of readily applicable C&I. This was based on a two round Delphi involving 37 people, aimed at defining the key criteria and a broad set of indicators, and a final face-to-face meeting with a smaller group of experts, aimed at refining the list of indicators and making them operational. Finally, 8 criteria and 22 indicators were obtained, whose main advantage is their spatial character, which makes them suitable for spatial analysis and mapping. The second objective was the development of a GIS-based multicriteria methodology to identify reforestation priorities, to design a number of landscape-scale reforestation options and to assess them according to their socio-ecological performance. The prioritisation was based on two main non-compensatory factors: the need for biodiversity conservation and the ecological feasibility of reforestation. Suitability maps were generated for both factors through spatial multicriteria analysis and threshold pairs used to extract priority areas. The minimum suitability levels and the total area to be reforested were used as input parameters to generate a finite number of resulting reforestation options. These were assessed for their ability to conserve biodiversity and improve living conditions of local communities by introducing additional ecological and socioeconomic indicators. The methodology was tested in an area of Chiapas (Mexico), where forest degradation is significant and poverty widespread. The tool proved to be effective in shaping compact reforestation areas and easy to use. Nevertheless, it does not allow the user to a priori define targets on both conservation and livelihood standards. Also, the forest-poverty link was little explored and the issue of access to forest resources totally neglected. This leads to the third objective of the thesis: the definition of a spatial optimization model to re-design the landscape mosaic through reforestation in a way that nature protection is enhanced, the provision of ecosystem services is ensured and livelihoods are sustained. Either one of two possible uses was assigned to forest: protection, if forest is primarily devoted to biodiversity conservation, and harvest, if forest is available for the collection of timber. The model, which is an Integer Programming-based one, identifies land to be reforested and assigns this to the two uses such that all environmental classes over the landscape are adequately covered by protected forest, each village has a sufficient amount of harvestable forest at short distance and a given amount of erosion-prone land is reforested. The model also accounts for opportunity costs, by limiting the amount of economically strategic lands (e.g. agriculture) to be converted to forest. The model is the first of its kind to account for local peopleâ€TMs livelihoods by ensuring the accessibility to natural resources. The application to a case study in central Chiapas (Mexico) showed that increasing the demand for the provision of an ecosystem service does not significantly affect the ecological benefits up to a given threshold. Although some assumptions had to be made, the model provided a demonstration that the principles of the FLR can be put in practice and ad hoc planning tools can be designed to support decision-makers in their activity. Most of all, the model provided a solution to the problem of conserving biodiversity in poor regions where maintaining the access to local natural resources is vital to people. Redesigning forest landscapes for nature conservation and livelihood improvement is a difficult task. But one of dramatic importance as well. This study provided tools that can be of practical help to decision-makers and planners willing to undertake the challenge. Nevertheless, the problem is complex and intrinsically affected by uncertainty: further research effort is needed to test indicators, include the time dimension into the model and involve stakeholders in the decision process.

Increasing energy demand driven by rapid population and economic growth, the need for climate change mitigation, and the depletion of fossil fuels is stimulating the search for renewable, climate neutral energy sources. Hydropower provides an efficient, low maintenance and flexible form of energy, which can provide ancillary benefits such as flood control, water storage and job creation. Yet, the construction of dams for hydropower production has been recognised by scientists as one of the major threats to the ecological integrity of river systems. For instance, the fragmentation of river systems alters the flow, thermal, and sediment regimes of rivers, and restricts the free movement of aquatic organisms. Disruption to the natural flow regime results in the degradation of physical habitat features which generate acoustic stimuli that are relevant to organisms. In addition, initial flooding of terrestrial habitats results in the rapid decay of organic matter, which releases greenhouse gases (GHG) into the atmosphere. Conservation and management of river systems therefore requires a greater understanding of the processes and mechanisms which underpin the ecohydrological impacts of hydropower. In this context, this doctoral thesis aims to investigate: (i), the ramifications of a global boom in hydropower construction, (ii) the prediction of GHG emissions from hydropower reservoirs, and (iii) the temporal and spatial changes in underwater river soundscapes affected by hydropower. Researchers have investigated the social, economic and ecological consequences of reservoir construction for decades. However, the lack of coordinated, georeferenced databases has hindered catchment decision making, and limited the development of regional and global research in particular. In Chapter 1, the primary objectives were to create a high resolution, georeferenced database of hydropower dams under construction or planned to assess the dimension and spatial distribution of hydropower developments, their density relative to available catchment water resources and the future impact on river fragmentation. Data were collected on hydropower schemes under construction or planned with a capacity of 1 MW or above, from government and non-government databases, grey literature and news reports. Spatial analyses were conducted in a geographical information system (GIS) on the extent of global development, impact per water availability and potential consequences for existing status of river fragmentation. The relative contribution of hydropower reservoirs to the global GHG budget, particularly in sub-tropical and tropical regions, remains the subject of intense critical debate. The initial objective of the second study was therefore, to identify principal parameters and underlying processes that drive GHG emissions from reservoirs. The second step was to review global reservoir emission measurements and their source pathways in hydropower systems. Meteorological and landscape derived parameters were then correlated with the GHG measurements in order to assess if and which selected parameters might explain variations in GHG emission data. Similarly, existing empirical models were applied to the measured data to assess their suitability in predictive modelling. Finally, a newly developed process based model (FAQ-DNDC v1.0) was used to simulate ‘net’ CO2 emissions from a newly flooded tropical reservoir and compared to the measured results. The final study (Chapter 3) examined the influence of hydropower systems on the underwater acoustic properties of river habitats. Using recently developed acoustic sensors in addition to traditional hydrophones, the study characterised the temporal and spatial changes in river soundscapes affected by hydropeaking, compared their frequency composition to unaffected river soundscapes, and critically appraised the ecological implications. The results of Chapter 1 indicate that we are now experiencing an unprecedented growth in global hydropower construction. Over 3,700 dams are planned or under construction, primarily in Africa, South America and East Asia. The expansion in dam building will reduce the number of free flowing rivers on a global scale by approximately 21%. The results of Chapter 2 show that variation in measured emissions due to the inherent heterogeneity of the underlying processes, in addition to methodological limitations, impede the prediction of GHG emissions. Source pathways of CO2 are similar for the majority of systems, however, pathways of CH4 emissions are highly variable and dependent on local operating conditions and the configuration of the given hydropower system. A newly developed process based model (FAQ-DNDC v1.0) shows that a mechanistic approach may provide the basis for the ‘net’ assessment of future hydropower reservoirs. Chapter 3 reveals that distinct river soundscapes undergo changes which are highly correlated to hydropower operations, and thus rapid sub-daily changes occur at timescales not often found in natural systems. These changes occur mostly in low frequency bands, which are within the range of highest acoustic sensitivity for fish. In pool habitats affected by hydropeaking, sound pressure levels in the lower frequencies (~0.0315 kHz) may increase by up to 30 decibels. Similarly, sound pressure levels of riffles increase by up to 16 decibels in the low to mid frequencies (~0.250 kHz). Overall, the findings of this thesis have a number of implications for river catchment management. Hydropower construction is taking place in some of the most ecologically sensitive areas of the globe, thus, this research provides a timely contribution to: (i) Provide a foundation for future research at catchment, regional and global scales. For instance, systematic conservation based planning is required to designate ‘no go’ areas to promote the long-term survival of biodiversity. Strategic positioning of future dams or reconfiguration of existing hydropower systems may reduce the combined impacts on biodiversity and GHG emissions without losing power capacity. (ii) Assess driving parameters of GHG emissions, critically appraise current predictive GHG emission models and use a process based approach to simulate ‘net’ emissions from a sub-tropical reservoir. Future reservoirs will sequester, mineralise and emit an increasing quantity of carbon to the atmosphere, and subsequently, will take a greater role in the global GHG budget. This research concludes that, in some cases empirical models may not be suitable for making robust estimations of future GHG’s from hydropower reservoirs. Combining the underlying carbon cycling processes within a process-based model allows the estimation of ‘net’ CO2 emissions from hydropower reservoirs. This approach may be integrated by catchment planners into the future lifecycle assessment of hydropower reservoirs. (iii) Characterise acoustic changes in underwater sound in rivers affected by hydropeaking. The findings emphasise that flow regulation by hydropower results in rapid changes to the amplitude and frequency spectrum of the riverine acoustic environment. These changes persist for longer periods than other forms of anthropogenic sound and may have implications for the whole biota. Thus, future studies should focus on measuring the behavioural and physiological impact on riverine organisms in order to develop guidelines for hydropower licensing.