This thesis combines field and laboratory studies to address some of the most pressing questions in the field of microplastic research. Specifically, the thesis addresses the topic of microplastics... Show moreThis thesis combines field and laboratory studies to address some of the most pressing questions in the field of microplastic research. Specifically, the thesis addresses the topic of microplastics in the freshwater environment. The research presented covers both the environmental presence and abundance of microplastics, in addition to ecological effects, investigated using observational and experimental studies. These studies give a greater understanding of the abundance, types and sources of microplastics in freshwater systems in the UK, how organisms and chemicals interact with microplastics and the potential ecological effects on a range of freshwater organisms from different functional feeding groups and trophic levels. Show less
This thesis describes the genetic and prokaryotic diversity of giant barrel sponges. Although it was originally believed that the giant barrel sponges in the AtlanticOcean and the Indo-Pacific... Show moreThis thesis describes the genetic and prokaryotic diversity of giant barrel sponges. Although it was originally believed that the giant barrel sponges in the AtlanticOcean and the Indo-Pacific Ocean were two different species, our analyses showed thatthere are several species in both ocean basins. Even more remarkable, is that each species is most closely related to a species in the other ocean basin. According to our analysis, there are threegiant barrel sponge species in the Atlantic Ocean, and, at least, six in the Indo-Pacific Ocean. Sponges house a large and diverse community of microorganisms. It is generally believed thatthese microorganisms play a central role in the physiological processes in the host. It appears that the region in which a giant barrel sponge occursmainly determines the composition of their microbial community. However, if you lookat a smaller scale within a region, for example within one reef or around an island suchas Curaçao, it appears that not only is the geographical location important, but the hostspecies to which an individual belongs also plays an important role. Show less
While ecosystems have concrete benefits for human society, these benefits are typically overlooked in decision-making. This is problematic because ecosystems – and thus the benefits that... Show moreWhile ecosystems have concrete benefits for human society, these benefits are typically overlooked in decision-making. This is problematic because ecosystems – and thus the benefits that ecosystems provide – are under increasing pressure from human actions. The ecosystem services concept aims to better reflect the benefits of ecosystems for human wellbeing. As a tool to quantify ecosystem services, their value is often estimated in monetary terms. This thesis investigates whether this approach is valid in ecological terms: do monetary value estimates adequately reflect the ecological status of the ecosystem? Two sets of water-related services in two different types of regions have been investigated: water quantity-related services in global drylands (chapters 2 and 3) and water quality-related services in the Scheldt river basin (chapters 4 and 5). The results show that the selected methodological approach has a dominant impact on value estimates for water-related services, while the ecological status of the ecosystem is of minor importance. This finding casts doubts upon the validity of monetary valuation as a means to take the ecological status of ecosystems into account in public decision-making. Future research should explore how the ecosystem’s ecological status can be better integrated in the valuation of ecosystem services. Show less
Large carnivore population is globally declining as a result of the fragmentation of habitat, large prey depletion and retaliatory killing by pastoralists. Despite Kenya declaring approximately 8... Show moreLarge carnivore population is globally declining as a result of the fragmentation of habitat, large prey depletion and retaliatory killing by pastoralists. Despite Kenya declaring approximately 8 percent of the land as wildlife protected areas, there are less than 2000 lions left in the wild. This trend is worrying and Kenya Wildlife Service developed conserve and manage large carnivores’ strategy. This justify the reason for Nairobi Lion Research Project. Understanding the factors influencing human–lion conflicts would reduce retaliatory killing of lions and improve conservation of lions. Therefore, the aim of this study is to ensure conservation of lions in NNP and in the surrounding areas, specifically in relation to human–lion conflicts. It focuses on population size and pride structure, home ranges and movements, prey choice and diets and examine socio-economic aspects of lion–livestock conflicts and application of LED flashlights. I found that Nairobi National Park has high lion’s density per100 km2, small home range and avoid the urban fringe of Nairobi City. They supplement diet with very small prey (<5 kg). Partial fencing of parks is not a solution to human-lion conflicts and LED flashlight technology is effective in reducing nocturnal livestock depredation at bomas by lions. Show less
This thesis aimed to investigate the impact of exposure dynamics, relative contributions of ENPs(particle) and ENPs(ion), and dosing regimens on the toxicity of ENPs varying in different physico... Show moreThis thesis aimed to investigate the impact of exposure dynamics, relative contributions of ENPs(particle) and ENPs(ion), and dosing regimens on the toxicity of ENPs varying in different physico-chemical properties, on the composition and functioning of soil microbial communities. The physico-chemical properties of ENPs could change their fate, and the exposure dynamics thus need to be taken into consideration for realistically characterizing the time-variable exposure in assessing toxicity. The metabolic profile of microbial community could change according to ENPs shapes, with nanoplates being more toxic than nanospheres and polygons. Regarding the microbial community composition, the effect of ENPs depended on exposure time and concentration. However, the alterations in community composition were not expressed in terms of community functioning, which indicates that genus specific changes occurred but not yet necessarily reflected biological significance with regard to community functioning. Functional redundancy might contribute to community tolerance to ENPs exposure. When exposed to more realistic ENPs exposure scenarios with multiple dosing frequencies instead of one-time injection, the repetitive exposure with low-dosing could induce a tendency towards larger alteration of both community composition and functioning. Our study thus provided further insights in understanding the impact of NPs on soil microbial communities towards environmentally relevant assessment. Show less
Although nanoparticles are extensively used in various applications like consumer products and have most probably entered the environment, little is known about the effects of these particles on... Show moreAlthough nanoparticles are extensively used in various applications like consumer products and have most probably entered the environment, little is known about the effects of these particles on living organisms. In this thesis, we aim to understand how the size and shape of nanoparticles influence their toxicity. Not only do we compare the toxic effect of these material characteristics over a series of metallic nanoparticles, therewith eliminating the effect of the core-material, but do we also investigate on an individual level where the particles migrate to inside the organism. This thesis aims to obtain a better understanding of the uptake, biodistribution and subsequent toxicity of nanoparticles, moving forward from the “organism as a black box” principle to a more detailed understanding of the harm caused by nanoparticles. Show less
This thesis studied in depth the energy use and CO2 emissions of the industrial sector in China. As discussed in chapter 1, being responsible for about 84% of the Chinese CO2 emissions in 2015, the... Show moreThis thesis studied in depth the energy use and CO2 emissions of the industrial sector in China. As discussed in chapter 1, being responsible for about 84% of the Chinese CO2 emissions in 2015, the industrial sector plays a vital role in achieving the emission goals for China. The regional and sectoral heterogeneities have been considered since the industrial sector is distributed in different regions and consists of different sub-sectors. Chapter 2 studied the regional heterogeneity in industrial carbon intensity and its drivers in specific years of 1999. 2005, 2010 and 2015. Chapter 3 investigated the driving forces of industrial aggregate energy intensity (IAEI) and the contribution of each industrial sub-sector to the changes in IAEI. Chapter 4 studied to what extent performance convergence of energy-intensive industries across provinces can contribute to CO2 emission reductions and China’s emission goals. Chapter 5 provided a critical literature review on the historical drivers of industrial CO2 emissions and the projected ranges for future emissions against the backdrop of policy goals, both for the industrial sector as a whole, and for the major industrial sub-sectors (electricity generation, cement production, steel production, chemicals, petroleum and non-ferrous metals). Show less
Large carnivores and humans, along with their livestock, have co-existed for thousands of years. However, human population growth and an increase in economic activities are modifying the landscape... Show moreLarge carnivores and humans, along with their livestock, have co-existed for thousands of years. However, human population growth and an increase in economic activities are modifying the landscape for large carnivores and their prey. I studied the interaction between tiger and leopard in a human dominated landscape around Bardia National Park, Nepal. Due to the increase in number of tigers inside the park leopards may be pushed out of the park, where they become involved in conflicts while there may also be a spill-over of young tigers moving to the buffer zone. Tigers were not directly involved in conflict with people which were found from the presence of prey remains in their scats. Elephants were killing most of the humans whereas leopards were found to kill most of the livestock. For future conservation programs we need to focus on the conservation of tiger and leopard in human dominated landscape. Due to interaction with tigers, the leopards are living in close proximity with people and thereby get more involved in conflicts with local communities. Tigers enjoy a religious and cultural tolerance among the people living in the buffer zone whereas leopards lack such religious and cultural tolerance. Show less
