The water quality impact of a herd of 246 dairy cows crossing a stream ford was documented. Two cow crossings produced plumes of turbid water associated with very high concentrations of faecal indicator bacteria (Escherichia coli) and high suspended solids (SS) and total nitrogen (TN). On the first crossing, towards the milking shed, the cows were tightly-bunched and produced a sharp spike of contamination (E. coli peaking at 50 000 cfu/100 ml). After milking, the cows wandered back across the stream as individuals or small groups, and contaminants were less elevated, albeit for a longer period. Light attenuation, measured continuously by beam transmissometer, correlated closely with E. coli, SS, and TN, permitting the total yield of these contaminants to be estimated. Contaminant yields for M04005; Online publication date
The biomass and species composition of epilithic periphyton in oligotrophic Lake Taupo was measured over a full year. Measurements of photosynthetic carbon uptake were made during summer and early winter. The lake supported a high biomass of epilithic periphyton throughout the year, averaging 100-600 mg m -2 over the 0-35 m water depth and peaking in early summer. Periphyton extended to at least 40 m depth. Depthintegrated carbon fixation rates of 242-362 mg m -2 h -1 were measured. Periphyton constituted more than 90% of the algal biomass and carbon fixation within the littoral zone, but less than 2% of production on a whole-lake basis. Based on taxonomic composition, periphyton could be divided into three zones, surface (0-2 m), mid water (2-20 m) and deep (> 20 m). The diatoms Aulacosira granulata, Rhopalodia novae zealandiae, Epithemia sorex, and Fragilaria spp. dominated the deep assemblage, Tolypothrix tenuis and Mastogloia elliptica the mid water, and Scytonema, Dichothrix, and filamentous chlorophytes the shallow zone. Indicator pigments, analysed by high-performance liquid chromatography, confirmed these groupings. Biomassspecific rates of photosynthesis were low in shallow water (assimilation number 1 at 1 m depth) and at depths of 20 m and below, photosynthesis was light-limited. We hypothesise that the periphyton community was slow-growing and that the high biomass seen at all depths resulted from gradual accrual with low rates of loss.
There is considerable controversy as to whether there is an association between bowel disorders and autism. Using a bowel symptom questionnaire we compared 51 children with autism spectrum disorder with control groups of 35 children from special school and 112 from mainstream school. There was a significant difference in the reporting of certain bowel symptoms (constipation, diarrhoea, flatulence) and food faddiness between the autism group and the mainstream school control group. There was no significant difference between the autism group and children in the special schools except for faddiness, which is an autism specific symptom and not a bowel symptom. This study confirms previously reported findings of an increase in bowel symptoms in children with autism. It would appear, however, that this is not specifically associated with autism as bowel symptoms were reported in similar frequency to a comparison group of children with other developmental and neurological disorders.
Experiments were undertaken in a recirculating flume to determine the relationships among water velocity, thallus area, drag, and the probability of thallus breakage or detachment in the foliose green alga Ulva lactuca L. In all specimens tested to breaking point, thalli detached from their bivalve substrates as a result of stipe breakage rather than in midthallus or by holdfast detachment. There was no relationship between thallus size and drag at which detachment occurred. Rather, the probability of detachment was normally distributed about a mean drag of 0. 70 N (95% confidence limits 0.55–0.85 N). Average breaking stress of stipes was 345 kN.m‐2 (95% cl 250–485 kN.m‐2). Similar results were obtained in field experiments where the horizontal force required to detach thalli was measured directly as 0.93 N (95% cl 0.69–1.15 N). Drag coefficients of plants were not constant with water velocity but increased up to 0.4 m.s‐1, declining exponentially at velocities above this. Empirical relationships were established between coefficient of drag and Reynold's number and, hence, among drag, thallus area and water velocity. These relationships permitted estimation of mean water velocity at which plants of a given area would detach.
This paper provides an overview of the Motueka integrated catchment management (ICM) research programme. This research was based on the thesis that achieving ecosystem resilience at a catchment scale requires active measures to develop community resilience. We define a generic adaptive planning and action process, with associated knowledge management and stakeholder involvement processes, and illustrate those processes with observations from five research themes: (1) water allocation; (2) land use effects on water; (3) land and freshwater impacts on the coast; (4) integrative tools and processes for managing cumulative effects; and (5) building human capital and facilitating community action. Our research clearly illustrates the benefits for effective decision-making of carrying out catchment scale science and management within collaborative processes which patiently develop trusting relationships. We conclude that coastal catchments should be managed as a holistic continuum from ridge tops to the sea and that some processes like floods or loss of community resilience have decadal consequences, which support the need for long-term monitoring and investment.
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