Advancing Knowledge on Cyanobacterial Blooms in Freshwaters

Cyanobacterial blooms are a water quality problem that is widely acknowledged to have detrimental ecological and economic effects in drinking and recreational water supplies and fisheries. There is increasing evidence that cyanobacterial blooms have increased globally and are likely to expand in water resources as a result of climate change. Of most concern are cyanotoxins, along with the mechanisms that induce their release and determine their fate in the aquatic environment. These secondary metabolites pose a potential hazard to human health and agricultural and aquaculture products that are intended for animal and human consumption; therefore, strict and reliable control of cyanotoxins is crucial for assessing risk. In this direction, a deeper understanding of the mechanisms that determine cyanobacterial bloom structure and toxin production has become the target of management practices. This Special Issue, entitled “Advancing Knowledge on Cyanobacterial Blooms in Freshwaters”, aims to bring together recent multi- and interdisciplinary research, from the field to the laboratory and back again, driven by working hypotheses based on any aspect of mitigating cyanobacterial blooms, from ecological theory to applied research

A multi-proxy approach to track ecological change in Gunbower Wetlands, Victoria, Australia

The wetlands of the Murray-Darling Basin have come under the threat of a drying climate, the over-allocation of water for irrigation agriculture and widespread catchment disturbance. A synthesis of many paleolimnological assessments undertaken in the upper and lower sections of the Murray floodplain, and the Murrumbidgee, reveal considerable ecological change in wetlands from early in European settlement. The wetlands of the Gunbower Forest lie in the middle reaches of the Murray River. They are located on Gunbower Island that is deemed a wetland of international significance under the Ramsar Convention and an icon site under the Living Murray Initiative. Many Gunbower Island wetlands are located in protected forests, while others are within a zone developed for irrigation, mostly dairy, agriculture. This study analysed the sedimentary records of two wetlands within the forest estate and two within irrigation lands intending to compare long term change in the Gunbower wetlands to studies on floodplains both up and downstream, and to assess the relative impact of regional causes of change and that of local land use. Sediments constitute natural archives of past environmental changes. Sediment records were recovered from four wetlands and radiometric dating and multi-proxy paleoecological techniques were applied to assess how these wetlands have responded to changes in human occupation and other factors, such as climate. Then, extracted sediment cores were taken from Black (core length: 84 cm) and Green (86 cm) Swamps located in the forest, and Taylors (94 cm) and Cockatoo (74 cm) Lagoons were situated amongst dairy farms. In order to reconstruct ecological and water quality changes from the study sites, the cores were analysed using four different analysis techniques, i.e., Itrax-XRF (X-Ray Fluorescence) scanning, Lead-210 (210Pb) dating, Stable isotope and diatom analysis. XRF scanning provided evidence of the elemental composition of the cores. Detrital enrichment in the lower parts of all cores was observed, indicating elevated erosion rates or low water levels. In addition to this, some recent metal pollution was evident with high Cu, Ni and Pb inputs. Stable isotopes provided limited information on the carbon and nitrogen sources. TheDoctor of Philosoph

Remote Sensing of the Aquatic Environments

The book highlights recent research efforts in the monitoring of aquatic districts with remote sensing observations and proximal sensing technology integrated with laboratory measurements. Optical satellite imagery gathered at spatial resolutions down to few meters has been used for quantitative estimations of harmful algal bloom extent and Chl-a mapping, as well as winds and currents from SAR acquisitions. The knowledge and understanding gained from this book can be used for the sustainable management of bodies of water across our planet

Chinese Water Systems

This open-access book addresses latest Sino-German results of the joint research efforts within Major Water Program of the Chinese Government supported by German research funding. The Major Water Program aims at the restoration of polluted water environments and sustainable management of water resources in China. The joint BMBF-CLIENT project SINOWATER deals with three most significant and strongest polluted Chinese waters, the river Liao and the Dian-lake as well as Tai-lake in the area of the metropolises Shenyang, Kunming and Suzhou, respectively. The project was conducted by the Research Institute for Water and Waste Management at RWTH Aachen (FiW) e.V., Bavarian State Ministry of the Environment and Consumer Protection, Technical University of Munich, RWTH Aachen University, German and Chinese companies (Martin Membrane Systems AG, Steinhardt GmbH Wassertechnik, GuHong, JT-elektronik, bluemetric, Huawang Water, EVU Group, Atemis GmbH, i+f process GmbH) in close cooperation with Chinese Academy of Environmental Sciences, Tongji University, and the Dianchi Lake Management Authorities. Overall, the joint Sino-German research project SINOWATER provided solutions for the improvement of the water quality in the mentioned water bodies as well as development and optimization of Good Water Governance. These objectives could be achieved through the implementation of innovative German water technologies and the optimization of water management elements in the fields of industrial and municipal wastewater treatment as well as river and shallow lake management

The importance of organic phosphorus sources, transfers and impacts across the agricultural continuum

This thesis investigates the risks posed by organic phosphorus (P) from agriculture to river and stream chemical water quality and the ecology. Organic P compounds have received limited attention in past research, due to the agronomic focus on inorganic P and the analytical challenges of quantifying organic P in environmental matrices. Through laboratory and field experiments, this thesis aimed to: (i) characterise organic P within fresh and stored livestock slurry; (ii) quantify organic P export within overland flow and leachate from grasslands, including following livestock slurry application; and (iii) determine the benthic microbial responses to organic P compounds in rivers and streams. Finally, a coupled terrestrial-aquatic modelling approach was developed to quantify the impact of diffuse agricultural P mitigation measures on river water quality. The organic P pool in fresh livestock slurry was substantial and dominated by monoesters, including glycerophosphates, other labile monoesters (e.g. ATP) and inositol-6-phosphates. Storage drove significant changes in the chemical and physical fractionation of P within slurry. Organic P was observed in overland flow and leachate from grassland soil. Significant increases in organic P concentrations within leachate followed slurry application, predominantly in the form of glycerophosphates and inositol-6-phosphates. Within streams, heterotrophic responses to glycerophosphates and inositol-6-phosphate were observed, although these varied depending on background stream P concentrations. However, under certain stream conditions, inhibitory effects of organic P on the autotrophic community were observed. Modelling the efficacy of agricultural P mitigation suggested a best-case scenario in which annual river total P loads decreased by 7.5%, yet this increased to 19.4-25.1% when wastewater effluent was addressed alongside agricultural sources of P. The outcomes of this thesis present an opportunity to develop an organic P focus to the P transfer continuum, alongside highlighting a range of future research priorities related to organic P in the environment

That's phat: The development and evaluation of compound-specific stable isotopes (CSSIs) of very long-chain fatty acids (VLCFAs) as a sediment tracing tool in a temperate climate

Rivers and lakes are subject to various forms of pollution from anthropogenic activity and natural sources. Many pollutants, such as those from agricultural runoff, are transported in rivers by binding to sediment. Sediment itself is a pollutant, and is often an indicator of terrestrial erosive processes. Common methods of establishing sediment provenance on a broad scale include the use of fallout radio nuclides and geochemistry. In 2008, Dr. Max Gibbs published a sediment tracing article on the use of compound-specific stable isotopes (CSSIs) of plant origin which identified sediment sources based on land use in sub-tropical New Zealand. The objective of the research undertaken here was to apply the CSSI concept to agricultural watersheds in a northern, temperate climate. Two watersheds were selected: the Horsefly River Watershed (HRW) near Horsefly, BC, Canada and the South Tobacco Creek Watershed (STCW), near Miami, Manitoba, Canada. The HRW represented a mostly pristine watershed. The STCW represented a heavily cropped agricultural watershed. The HRW samples were used to develop laboratory methodology, while the STCW samples were used to evaluate the CSSI technique using carbon stable isotopes. The dissertation addresses the following: (i) literature review of plant biomarkers and spatial/temporal variability of CSSIs due to biological, environmental and analytical factors; (ii) methodology, analysis and variability associated with bulk soil and sediment isotope determination; (iii) methodologies for processing soil and sediment from sampling to isotope analysis; and (iv) spatial and temporal variability of CSSI tracers. The CSSI tracers were evaluated to reveal spatial and temporal variability of VLCFA concentrations and isotope signatures at the point, transect and field scales. Weighted t-tests were used to differentiate sediment sources spatially and temporally. The use of bulk carbon as a proxy for VLCFA concentrations in source apportioning was also explored. The work presented here demonstrates the ability of CSSIs to differentiate sediment sources based on land use. The development of analytical methods and the resulting analysis of soil and sediment extracts have indicated that VLCFAs may be isolated and quantified to generate reliable isotope data. The methods will hopefully lead to the standardization of CSSIs protocols.pollution from anthropogenic activitybinding to sedimentindicator of terrestrial erosive processesfallout radio nuclides and geochemistryplant biomarkers and spatial/temporalspatial and temporal variabilit

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.Application of different irrigation management practices plays a considerable role in water saving to achieve potential yields. On the other hand, network water distribution schedule is a governing factor in this regard. In current study conducted in Mahabad plain in North West of Iran, four different irrigation managements on sugarbeet cultivation including traditional farmer's management, Furrow Deepening, Reduced Discharge per Deepened Furrow, and Alternate Furrow Irrigation have been studied in real farmers' fields measuring 10.2 hectares. Participatory management approach has been used while working in farmers' fields. Soils textures are silty clayey. Results of studies indicate that water used has been reduced considerably while higher root and sugar yields are obtained due to better on-farm water management practices. Water Use Efficiency, in kg of yield per m3 of water used, increased considerably under alternate furrow irrigation management in comparison to what obtained under traditional management. Results show application of alternate furrow irrigation in sugarbeet cultivation not only resulted in lesser water use per hectare, but also it increased both root and sugar yields and, consequently, higher water use efficiency was obtained. Assessments have been made on irrigation schedule imposed by the irrigation network and its effects on actual water requirements. Results show that the delivery schedule practiced in the network in incapable of delivering the actual amount of water requirement for the dominant crop of the scheme. Suggestions are made to the network operator to improve overall network efficiency including revisions on water resources planning and allocation and/or improve network operation system

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.As a lower riparian country Bangladesh is largely dependent on 57 transboundary rivers. The upstream courses of these river systems traverse India, China, Nepal, Bhutan and Myanmar. Each day, approximately 3,000 million cubic meters of water discharge into the Bay of Bengal through these rivers. However, flows are much lower during the dry season when surface water is critical to such uses as irrigation, salinity control, habitat preservation, effluent dilution and navigation. Unilateral diversion of water from the transboundary rivers impedes agricultural development using irrigation-fertilizers-modern varieties technology. Thus, sustainable irrigation system is instrumental for the growth of food production. For this, peoples' participation is prerequisite to form social capital in building consensus about the irrigation water uses. Local Government Engineering Department (LGED) has developed a model to facilitate sustainable use of water resources and demonstrated its effectiveness for irrigation management. It develops stakeholders-driven water infrastructure in subprojects each covering 1,000 ha or less. LGED involves local people in subproject planning, design, construction and operation and maintenance (O&M). It has constructed 320 subprojects under the Small Scale Water Resources Development Sector Project. Case study in a subproject in northwestern part of the country found that local stakeholders' participation in managing water resources and operation of water control infrastructure results in excellent performance of irrigation system and improvement of distribution system. This raises irrigation efficiency with productive use of water and releases constraints on land use through facilitating cultivation in three crop seasons and increases the proportion of irrigated area under small farms

Chapter 1.2: Tipping points in the cryosphere

Drastic changes in our planet’s frozen landscapes have occurred over recent decades, from Arctic sea ice decline and thawing of permafrost soils to polar amplification, the retreat of glaciers and ice loss from the ice sheets. In this chapter, we assess multiple lines of evidence for tipping points in the cryosphere – encompassing the ice sheets on Greenland and Antarctica, sea ice, mountain glaciers and permafrost – based on recent observations, palaeorecords, numerical modelling and theoretical understanding. With about 1.2°C of global warming compared to pre-industrial levels, we are getting dangerously close to the temperature thresholds of some major tipping points for the ice sheets of Greenland and West Antarctica. Crossing these would lock in unavoidable long-term global sea level rise of up to 10 metres. There is evidence for localised and regional tipping points for glaciers and permafrost and, while evidence for global-scale tipping dynamics in sea ice, glaciers and permafrost is limited, their decline will continue with unabated global warming. Because of the long response times of these systems, some impacts of crossing potential tipping points will unfold over centuries to millennia. However, with the current trajectory of greenhouse gas (GHG) emissions and subsequent anthropogenic climate change, such largely irreversible changes might already have been triggered. These will cause far-reaching impacts for ecosystems and humans alike, threatening the livelihoods of millions of people, and will become more severe the further global warming progresses. The scientific content of this chapter is based on the following manuscript in preparation: Winkelmann et al., (in prep