Ana T Castro-Castellon

Phytoplankton blooms compromise the quality of freshwater ecosystems and the efficient processing of water by treatment works worldwide. This research aims to determine whether in-situ filamentous biofiltration processes mediated by living roots and synthetic filters as media can reduce or remove the phytoplankton loading (micro-algae and cyanobacteria) prior to a potable water treatment works intake. The underlying biofiltration mechanisms were investigated using field and laboratory studies. A novel macroscale biofilter with three plant species, named the "Living-Filter", installed in Farmoor II reservoir, UK, was surveyed weekly for physicochemical and biological variables under continuous flow conditions during 17 weeks. The efficiency of a mesoscale biofilter using the aquatic plant Phalaris arundinacea and synthetic filters, was tested with Microcystis aeruginosa under continuous flow conditions and in batch experiments. The 'simultaneous allelochemical method' was developed for quantifying allelochemicals from Phalaris in aqueous samples. Microscale studies were used to investigate biofilter allelochemical release in response to environmental stressors and Microcystis growth inhibition in filtered and unfiltered aqueous root exudate. Results demonstrate that the removal of phytoplankton biomass by physical mechanisms has a removal efficiency of ≤45% in the "Living-Filter" (filamentous biofilter plus synthetic fabric) and that the removal of Microcystis biomass using only biofilters was 25%. Chemical mechanisms that reduce Microcystis cell numbers are mediated by allelochemicals released from biofilter roots. Root exudate treatments on Microcystis revealed that Microcystis growth is inhibited by allelochemicals, not by nutrient competition, and that protists and invertebrates play a role in removing Microcystis. Filamentous biofilters can remove phytoplankton biomass by physical, chemical and biological mechanisms. Biofilters and synthetic filters in combination improve removal efficiency. Application of macroscale biofilters prior to potable water treatment works benefits the ecosystem. Plant properties, biofilter size to surface water ratio, and retention time must be considered to maximise the benefits of biofiltration processes.</p

Ecologists, conservationists, and managers frequently need to recognise and survey different aquatic plant species, vegetation types, plant communities, or habitat. It is, after all, the vegetation that defines the extent of a freshwater wetland. This chapter reviews the methods used to survey both ‘terrestrial’ and ‘aquatic’ freshwater plants and considers the approaches taken, some of the specialised equipment used, and technical expertise needed to conduct wetland vegetation surveys. The techniques and approaches used and associated sampling strategies are considered for field surveys; experiments including meso- and macrocosms; and surveys involving remote sensing techniques. The chapter ends by examining a series of examples that illustrate how different vegetation research questions in ecology, conservation, and management can be answered using a diversity of methods.

During a 4-year-period, more than 500 ostriches and several rheas, all born in European countries and raised in Spain and Portugal, have been analyzed for the presence of ectoparasites and endoparasites. A total of 29 parasite species have been found, most of them of the gastrointestinal tract. Some of the helminth species found may represent spureous parasitosis, as only the eggs (of an ascarid and a trematode) were found in some samples. From the organisms identified, the ectoparasites (lice-Struthiolipeurus rheae, S. nandu; mites-Dermoglyphus pachycnemis, Gabucinia bicaudata), helminths (cestoda-Houttuynia struthionis- and nematoda-Libyostrongylus sp., Codiostomum struthionis-) and the ciliate Balantidium struthionis are known as ratite specific parasites. Capillaria eggs and larvae were also found; there are no previous records of this parasite from ostriches, and the data available do not allow to do a temptative specific diagnosis. Among protozoa, most of the species now found are described for the first time in ratites. They include organisms also found in other birds (Trichomonas gallinae, Tetratrichomonas gallinarum, Chilomastix gallinarum, Spironucleus meleagridis and Pleuromonas jaculans), and organisms whose specific status cannot be established until further analysis are performed (Cryptosporidium sp., Eimeria sp. and/or Isospora sp., Entamoeba sp. of the one-nucleate and of the eight-nucleate mature cyst groups, Endolimax sp., Iodamoeba sp., Monocercomonas sp., Retortamonas sp., Giardia sp., Blastocystis sp. and euglenids).

Phytoplankton blooms compromise the quality of freshwater ecosystems and the efficient processing of water by treatment works worldwide. This research aims to determine whether in-situ filamentous biofiltration processes mediated by living roots and synthetic filters as media can reduce or remove the phytoplankton loading (micro-algae and cyanobacteria) prior to a potable water treatment works intake. The underlying biofiltration mechanisms were investigated using field and laboratory studies. A novel macroscale biofilter with three plant species, named the "Living-Filter", installed in Farmoor II reservoir, UK, was surveyed weekly for physicochemical and biological variables under continuous flow conditions during 17 weeks. The efficiency of a mesoscale biofilter using the aquatic plant Phalaris arundinacea and synthetic filters, was tested with Microcystis aeruginosa under continuous flow conditions and in batch experiments. The 'simultaneous allelochemical method' was developed for quantifying allelochemicals from Phalaris in aqueous samples. Microscale studies were used to investigate biofilter allelochemical release in response to environmental stressors and Microcystis growth inhibition in filtered and unfiltered aqueous root exudate. Results demonstrate that the removal of phytoplankton biomass by physical mechanisms has a removal efficiency of ≤45% in the "Living-Filter" (filamentous biofilter plus synthetic fabric) and that the removal of Microcystis biomass using only biofilters was 25%. Chemical mechanisms that reduce Microcystis cell numbers are mediated by allelochemicals released from biofilter roots. Root exudate treatments on Microcystis revealed that Microcystis growth is inhibited by allelochemicals, not by nutrient competition, and that protists and invertebrates play a role in removing Microcystis. Filamentous biofilters can remove phytoplankton biomass by physical, chemical and biological mechanisms. Biofilters and synthetic filters in combination improve removal efficiency. Application of macroscale biofilters prior to potable water treatment works benefits the ecosystem. Plant properties, biofilter size to surface water ratio, and retention time must be considered to maximise the benefits of biofiltration processes.</p

Over 60% of the global population are expected to live in urban areas by 2050. Urban blue spaces are critical for biodiversity, provide a range of ecosystem services, and can promote human health and wellbeing. Despite this, access to blue space is often unequally distributed across socioeconomic gradients, and the availability of quality blue space could extend to environmental justice issues. Three stages of analysis were carried out in Mexico City, Mexico and Bristol, UK to (i) assess associations between blue space and socioeconomic metrics at a regional scale, (ii) apply a rapid assessment tool to assess amenity, access and environmental quality, (iii) consider local quality across socioeconomic gradients at a regional scale. Still water availability was indicative of higher socioeconomic status, but contrasting city evolutions underpinned differences. Locally, there were environmental gradients from more complex to disturbed habitats that influenced potential wellbeing and amenity benefits. In combination, this may exacerbate inequalities and risk increasing ecosystem disservices. If cities are to be socially, and environmentally resilient to higher levels of disturbance in the future, healthy ecosystems will be key. However, further research is needed to address various dimensions of injustice in urban areas beyond blue space distribution.

Organic-matter decomposition is a key ecosystem process in freshwater ecosystems as it influences food web dynamics, represents a considerable flux in the global carbon cycle and can provide a useful measure of the 'health' of freshwater habitats. While organic-matter decomposition has been well studied among lotic ecosystems, research from small standing waterbodies such as ponds is largely missing, and decomposition studies are usually conducted on a single freshwater habitat type. However, there is a need to consider ecosystem processes across multiple freshwater habitats and connected ecosystems to better characterise ecosystem functioning at the landscape-scale, given the interdependence of landscape elements. This study provides a comparative analysis of organic-matter decomposition using a standardised field assay (cotton-strip assay) in the water column, riparian zone and land zone of urban pond and stream habitats. The average daily tensile-strength loss of the cotton strips (a process that corresponds to the catabolism of cellulose by microbes) was significantly higher in the aquatic habitats than riparian and land zones when all sites were considered, and when stream and pond sites were considered separately. Furthermore, the average decomposition rate was significantly higher within the water column in river habitats compared to pond habitats, although no difference was observed among riparian and land zones. Woody debris had a negative unimodal association with average per day tensile strength loss within streams, and a positive unimodal association within pond sites. Both nitrate and shading had positive unimodal associations with average per day tensile strength loss within stream sites. Among pond habitat, urban land coverage within 250m of each site was identified to have a negative association with average per day tensile strength loss. Here we demonstrated that urban freshwater habitats have heterogeneous organic matter decomposition rates, and that the responses can be complex. Understanding key ecosystem processes at a multihabitat scale will ensure the effective inclusion of ecosystem process in freshwater assessment and conservation protocols and improve the health and resilience of urban freshwater ecosystems.

Ecologists, conservationists, and managers frequently need to recognise and survey different aquatic plant species, vegetation types, plant communities, or habitat. It is, after all, the vegetation that defines the extent of a freshwater wetland. This chapter reviews the methods used to survey both ‘terrestrial’ and ‘aquatic’ freshwater plants and considers the approaches taken, some of the specialised equipment used, and technical expertise needed to conduct wetland vegetation surveys. The techniques and approaches used and associated sampling strategies are considered for field surveys; experiments including meso- and macrocosms; and surveys involving remote sensing techniques. The chapter ends by examining a series of examples that illustrate how different vegetation research questions in ecology, conservation, and management can be answered using a diversity of methods.

The Living-Filter is a novel floating emergent treatment wetland design that combines a hydroponic plant-bed with curtains and baffles. Thames Water Utilities and AquaticEngineering UK designed and installed the Living-Filter in Farmoor II reservoir, Oxfordshire, UK, in July 2012. The aim is to reduce the phytoplankton biomass prior to the water treatment works intake. The plant-bed (1 m H × 21 m W × 10 m L) supports plants of Phragmites australis, Phalaris arundinacea and Carex acutiformis, with a combined system of curtains and baffles that aid the water to flow through the Living-Filter. All the water treated at the water treatment works has passed through the Living-Filter. The roots and a plastic fabric increase the surface area for biofiltration processes and the rhizosphere provides refuge for zooplankton. The research attempts to answer the question: Can the Living-Filter be used as an in-reservoir pre-treatment filtration process for reducing the phytoplankton biomass onto the water treatment works? Weekly surveys were carried out from July to October 2013 at sixteen sampling sites to measure physico-chemical and biological variables. The results for the first year of study show: (1) Soluble manganese, dissolved inorganic nitrogen and nitrites were significantly lower after treatment through the Living-Filter. (2) Chlorophyll-a removal efficiency was up to 45% during the first seven weeks. (3) Zooplankton abundance was more stable within the rhizosphere than in the water column. (4) The aerial shoots of the plants developed well, but based on root development only Phalaris and Carex should be considered for future designs. This work highlights the potential of the Living-Filter for phytoplankton reduction, but it also addresses questions that will further improve the system.

In contrast to marine ecosystems, the toxicity impact of microplastics in freshwater environments is poorly understood. This contribution reviews the literature on the range of effects of microplastics across and between trophic levels within the freshwater environment, including biofilms, macrophytes, phytoplankton, invertebrates, fish and amphibians. While there is supporting evidence for toxicity in some species e.g. growth reduction for photoautotrophs, increased mortality for some invertebrates, genetic changes in amphibians, and cell internalization of microplastics and nanoplastics in fish; other studies show that it is uncertain whether microplastics can have detrimental long-term impacts on ecosystems. Some taxa have yet to be studied e.g. benthic diatoms, while only 12% of publications on microplastics in freshwater, demonstrate trophic transfer