Investigating Multiple Household Water Sources and Uses with a Computer-Assisted Personal Interviewing (CAPI) Survey

The investigation of multiple sources in household water management is considered overly complicated and time consuming using paper and pen interviewing (PAPI). We assess the advantages of computer-assisted personal interviewing (CAPI) in Pacific Island Countries (PICs). We adapted an existing PAPI survey on multiple water sources and expanded it to incorporate location of water use and the impacts of extreme weather events using SurveyCTO on Android tablets. We then compared the efficiency and accuracy of data collection using the PAPI version (n = 44) with the CAPI version (n = 291), including interview duration, error rate and trends in interview duration with enumerator experience. CAPI surveys facilitated high-quality data collection and were an average of 15.2 min faster than PAPI. CAPI survey duration decreased by 0.55% per survey delivered (p < 0.0001), whilst embedded skip patterns and answer lists lowered data entry error rates, relative to PAPI (p < 0.0001). Large-scale household surveys commonly used in global monitoring and evaluation do not differentiate multiple water sources and uses. CAPI equips water researchers with a quick and reliable tool to address these knowledge gaps and advance our understanding of development research priorities

The trophic importance of epiphytic algae in a freshwater macrophyte system (Potamogeton perfoliatus L.): stable isotope and fatty acid analyses

Stable isotope and fatty acid analyses were used to study carbon sources for animals in a submerged plant bed. Epiphytes growing on Potamogeton perfoliatus, sand microflora, and alder leaves were the most important carbon sources. The most abundant macrophyte, P. perfoliatus was unimportant as a food source. Modelling (IsoSource) showed that epiphytes were the most important food source for the most abundant benthic invertebrates, the isopod Asellus aquaticus (annual mean contribution 64%), the amphipod Gammarus pulex (66%), and the gastropod Potamopyrgus antipodarum (83%). The mean annual contributions of sand microflora were, respectively, 21, 19, and 9%; and of alder leaves, 15, 15, and 8% for these three species. The relative importance of carbon sources varied seasonally. The relative contribution of epiphytes was lowest for all three grazer species in July: A. aquaticus 38%, G. pulex 43%, and P. antipodarum 42%. A decline in epiphyte biomass in summer may have caused this switch to less attractive food sources. P. perfoliatus provided habitat and shelter for consumers, but food was mainly supplied indirectly by providing space for attached epiphytes, which are fast-growing and provide a highly nutritious food source

Pollen, biomarker and stable isotope evidence of late Quaternary environmental change at Lake McKenzie, southeast Queensland

Unravelling links between climate change and vegetation response during the Quaternary is important if the climate–environment interactions of modern systems are to be fully understood. Using a sediment core from Lake McKenzie, Fraser Island, we reconstruct changes in the lake ecosystem and surrounding vegetation over the last ca. 36.9 cal kyr. Evidence is drawn from multiple sources, including pollen, micro-charcoal, biomarker and stable isotope (C and N) analyses, and is used to gain a better understanding of the nature and timing of past ecological changes that have occurred at the site. The glacial period of the record, from ca. 36.9 to 18.3 cal kyr BP, is characterised by an increased abundance of plants of the aquatic and littoral zone, indicating lower lake water levels. High abundance of biomarkers and microfossils of the colonial green alga Botryococcus occurred at this time and included large variation in individual botryococcene d13C values. A slowing or ceasing of sediment accumulation occurred during the time period from ca. 18.3 to 14.0 cal kyr BP. By around 14.0 cal kyr BP fire activity in the area was reduced, as was abundance of littoral plants and terrestrial herbs, suggesting wetter conditions from that time. The Lake McKenzie pollen record conforms to existing records from Fraser Island by containing evidence of a period of reduced effective precipitation that commenced in the mid-Holocene

Zooplankton responses to freshwater inflows and organic-matter pulses in a wave-dominated estuary

Freshwater inflow events play a major role in structuring estuarine zooplankton communities. Freshwater inflow events affect zooplankton directly through advective forcing and changes in salinity, and indirectly through changes to resources by the delivery of organic carbon and nutrients that can stimulate microbial and primary production. Here, we investigate changes to estuarine zooplankton assemblage structure, density and δ13C stable isotopes during a period of highly variable freshwater inflow in the Bega River estuary, Australia. High inflows resulted in a reduction of salinity and a shift in the zooplankton assemblage structure from purely estuarine taxa towards freshwater taxa. The density of select genera of rotifers, cladocera and, in the upper estuary, copepods, increased following inflows, concurrent with increases in the concentration of dissolved organic carbon and bacterial biomass. Redundancy analysis found that environmental variables including discharge, dissolved organic carbon, salinity and bacterial biomass explained 66-73% of zooplankton variation. Stable isotope results indicated that all copepod and cladocera species tested were predominantly supported by allochthonous carbon from terrestrial sources. The present results have provided important evidence that freshwater inflows play a critical role in structuring zooplankton assemblages and supporting increased production through the delivery of allochthonous organic carbon

Disruption in water quality patterns along the river continuum by a large bottom release dam

© 2015 Environment Institute of Australia and New Zealand Inc. Understanding longitudinal variation in water quality along rivers and how they are influenced by large dams is important for both ecological theory and river management. This study examines longitudinal changes in water quality downstream of a large bottom release dam (Lake Copeton) on the Gwydir River, Australia. We compared longitudinal changes in water quality variables from sites upstream and downstream of Lake Copeton over a two-year period and a total river distance of approximately 200 km. Lake Copeton acted as a source of nitrogen as nitrogen oxides (NOx) and phosphorus as filterable reactive phosphorus (FRP). A significant increase in the concentration of NOx and FRP was evident downstream of the dam, particularly in summer with elevated concentrations detected up to 60 km downstream. Significantly lower chlorophyll a (Chl-a) concentrations and electrical conductivity (EC) were evident below the dam. Mean nutrient concentrations declined with increased distance downstream of Lake Copeton while Chl-a concentrations increased, suggesting uptake by autotrophs. This study suggests that Copeton Dam disrupts the river continuum for nutrients, Chl-a and EC as predicted by the serial discontinuity concept, with recovery occurring approximately 60 km downstream

Addressing how multiple household water sources and uses build water resilience and support sustainable development

Abstract The routine use of multiple water sources to meet household water needs is widely practiced and has been reported in many developing countries. However, it is typically neglected by implementers, development organizations, and researchers who tend to focus exclusively on the “main source of drinking water.” In this Perspective, we explain the nature and scope of multiple water source use (MWSU) at the household level in developing countries. We also describe the implications of MWSU for human health and water resilience, and identify key knowledge gaps, risks, and opportunities associated with MWSU. Finally, we argue that understanding MWSU is feasible for researchers and implementers and is essential for properly designing research studies and water supply projects

Terrestrial dissolved organic carbon subsidizes estuarine zooplankton: An in situ mesocosm study

© 2016 Association for the Sciences of Limnology and Oceanography. Freshwater inflows play an important role in delivering dissolved organic carbon (DOC) to estuaries. Episodic inputs of DOC may support increased bacterial production. However, the role of DOC in supporting zooplankton production is widely debated. To evaluate this role we performed an in situ mesocosm experiment in the Bega River estuary, Australia. We added a DOC leachate derived from terrestrial vegetation to 400 L mesocosm bags as treatments of +1.5, +3, and +16 mg C L-1 and monitored changes in carbon, nitrogen, phosphorus, bacteria, chlorophyll a (Chl a), and zooplankton over 22 d. Bacterial biomass peaked at day 2 and was highest in the +16 mg C L-1 treatment. Chl a was not significantly different between treatments. Mesozooplankton was dominated by copepodites of Gladioferens pectinatus and Sulcanus conflictus between days 5-9 and by adults between days 9-15. Significantly higher numbers of copepods were present in the +16 treatment followed by the +3 mg C L-1 treatment compared with the controls. Stable carbon isotope signatures of copepods in the +16 mg C L-1 treatment were significantly different from the control and showed leachate carbon supported between 29.3% and 55.8% of copepod biomass. These results suggest that the impact of allochthonous DOC loading events on estuarine zooplankton occurs over short periods, and that the magnitude of response is, in part, controlled by the quantity of bioavailable DOC loaded to the system. Our findings underscore the importance of microbial dynamics stimulated by DOC loading events from freshwater inflows as a trophic path in estuarine food webs

Longitudinal trends in river functioning: Patterns of nutrient and carbon processing in three Australian rivers

Understanding longitudinal trends in the processing of carbon in rivers represents a much conceptualised, but infrequently tested, issue in aquatic ecology. In this study, we conducted concurrent longitudinal examinations of three very different rivers in eastern Australia to determine whether general principles in river functioning exist across broad geographic and hydrologic scales. Specifically, we examined trends in ambient basic water chemistry, nutrient concentrations, dissolved organic carbon (DOC), extracellular enzymes and food web structure and functioning and conducted bioassays to examine the degree to which DOC and nutrients limit heterotrophic bacterial respiration. These parameters revealed striking similarities across all sites. For metazoan communities, stable isotope analysis showed that algal carbon was the dominant basal resource utilised by consumers in all three rivers, suggesting that in-stream primary producers strongly underpin trophic pathways regardless of the position within a catchment or catchment condition. Analyses of extracellular enzymes revealed that microbial communities are actively utilising DOC at all sites. In fact, heterotrophic microbial respiration was strongly limited by DOC at all sites, with nutrient additions resulting in only relatively minor increases in respiration. Ultimately, this study demonstrates that DOC and algal carbon are critically important drivers of ecosystem processes in Australian riverine ecosystems. Furthermore, across all of our sites and rivers, ambient nutrient concentrations did not influence carbon processing. The consistent longitudinal trends in river function identified in this study provide useful insights for catchment managers and modellers with respect to identifiying key principles that underpin ecosystem functioning in Australian rivers. Copyright © 2009 John Wiley & Sons, Ltd. Copyright © 2009 John Wiley & Sons, Ltd

Understanding and overcoming baseline isotopic variability in running waters

Natural abundances of stable isotopes in lotic food webs yield valuable information about sources of organic matter for consumers and trophic structure. However, interpretation of isotopic information can be challenging in the face of variability in organisms at the base of food webs. Unionid and dreissenid mussels, commonly used as baseline organisms in lakes, are uncommon in many river settings and can have variable diets, thus making them unsuitable as a universal baseline for many river food web studies and often forcing reliance on more common benthic insects for this purpose. Turnover rates of body carbon and nitrogen in insects are relatively rapid (1 to 50days half-life). These rapid turnover rates in primary consumers can result in considerable temporal variability in δ13C that rivals that of algae (>10‰ range within a site). This suggests that using primary consumers as a surrogate baseline for algae may not circumvent the problem of temporal variability and the resultant mismatch of sources with longer-lived, slow-growing secondary and tertiary consumers. There are several strategies for reducing the influence of these confounding factors when bivalves with a known diet are not present. These include sampling over large spatial scales and correlating δ13C of consumers with the source of interest (e.g. benthic algae), sampling baseline organisms multiple times in the weeks preceding sampling of larger consumers (particularly in response to large changes in discharge) and using algal-detrital separation methods and multiple tracers as much as possible. Incorporating some of these recommendations and further exploring variability at the base of the food web will potentially provide greater insights into consumer-resource coupling in running waters and more robust conclusions about food web structure and energy flow in these dynamic systems. © 2012 John Wiley & Sons, Ltd