Use of in vivo phycocyanin fluorescence to monitor potential microcystin-producing cyanobacterial biovolume in a drinking water source

The source water of a drinking water treatment plant prone to blooms, dominated by potential microcystin-producing cyanobacteria, was monitored for two seasons in 2007-2008. In the 2008 season, the median value for potential microcystin-producing cyanobacterial biovolume was 87% of the total phytoplankton biovolume in the untreated water of the plant. Depth profiles taken above the plant's intake identified three sampling days at high risk for the contamination of the plant's raw water with potentially toxic cyanobacteria. Chlorophyceae and Bacillariophyceae caused false positive values to be generated by the phycocyanin probe when cyanobacteria represented a small fraction of the total phytoplanktonic biovolume present. However, there was little interference with the phycocyanin probe readings by other algal species when potential microcystin-producing cyanobacteria dominated the phytoplankton of the plant's untreated water. A two-tiered method for source water monitoring, using in vivo phycocyanin fluorescence, is proposed based on (1) a significant relationship between in vivo phycocyanin fluorescence and cyanobacterial biovolume and (2) the calculated maximum potential microcystin concentration produced by dominant Microcystis sp. biovolume. This method monitors locally-generated threshold values for cyanobacterial biovolume and microcystin concentrations using in vivo phycocyanin fluorescence.     

GIS As A Tool For Assessing The Influence Of Countryside Designations and Planning Policies On Landscape Change

The county of Bedfordshire is typical of landscape in lowland England with land cover dominant over land form and agriculture forming the major land use. Landscape change can be influenced by planning policies through their control of land use. A number of designated areas such as Areas of Great Landscape Value, Areas of Outstanding Natural Beauty and Green Belt have been defined where particular planning priorities for the conservation of the countryside apply. This paper reports work where an attempt has been made to measure the influence of these designations on landscape change using the tools of aerial photograph interpretation and Geographic Information Systems (GIS). Aerial photographs were available for the study area for 1968, 1981 and 1991. These were interpreted to a landscape classification scheme in terms of point, linear and area features such as trees, hedgerows and cultivated land, respectively. Field work was carried out to assess the accuracy of the interpretation. The resulting data were input to a GIS for each date of photography. Digital maps were created for the land cover features and tables were generated of lengths of linear features or counts of point features for each kilometre square in the study area. Spatial analysis tools provided by the GIS were used to describe the landscape character of each of the designated areas and then to measure the change that had taken place within them over the time period defined by the photography. Areas which were not designated for conservation of scenic beauty were shown to be poorer in traditional landscape features.     

Rabbit biocontrol and landscape‐scale recovery of threatened desert mammals

Funding for species conservation is insufficient to meet the current challenges facing global biodiversity, yet many programs use expensive single‐species recovery actions and neglect broader management that addresses threatening processes. Arid Australia has the world's worst modern mammalian extinction record, largely attributable to competition from introduced herbivores, particularly European rabbits (Oryctolagus cuniculus) and predation by feral cats (Felis catus) and foxes (Vulpes vulpes). The biological control agent rabbit hemorrhagic disease virus (RHDV) was introduced to Australia in 1995 and resulted in dramatic, widespread rabbit suppression. We compared the area of occupancy and extent of occurrence of 4 extant species of small mammals before and after RHDV outbreak, relative to rainfall, sampling effort, and rabbit and predator populations. Despite low rainfall during the first 14 years after RHDV, 2 native rodents listed by the International Union for Conservation of Nature (IUCN), the dusky hopping‐mouse (Notomys fuscus) and plains mouse (Pseudomys australis), increased their extent of occurrence by 241–365%. A threatened marsupial micropredator, the crest‐tailed mulgara (Dasycercus cristicauda), underwent a 70‐fold increase in extent of occurrence and a 20‐fold increase in area of occupancy. Both bottom‐up and top‐down trophic effects were attributed to RHDV, namely decreased competition for food resources and declines in rabbit‐dependent predators. Based on these sustained increases, these 3 previously threatened species now qualify for threat‐category downgrading on the IUCN Red List. These recoveries are on a scale rarely documented in mammals and give impetus to programs aimed at targeted use of RHDV in Australia, rather than simply employing top‐down threat‐based management of arid ecosystems. Conservation programs that take big‐picture approaches to addressing threatening processes over large spatial scales should be prioritized to maximize return from scarce conservation funding. Further, these should be coupled with long‐term ecological monitoring, a critical tool in detecting and understanding complex ecosystem change.     

First continuous shipboard δ18O and δD measurements in sea water by diffusion sampling—cavity ring-down spectrometry

Combined measurements of salinity and the oxygen/hydrogen stable isotope composition of marine waters can characterise processes such as freshwater mixing, evaporation, precipitation and sea-ice formation. However, stable isotope data with high spatial and temporal resolution are necessary for a detailed understanding of mixed water bodies with multiple inputs. So far analysis of ??¹⁸O and ??D values in water has been a relatively expensive, laboratory-based technique requiring collection of discrete samples. This has greatly limited the scope and scale of field research that can be undertaken using stable isotope analysis. Here, we report the first continuous shipboard measurements of ??¹⁸O and ??D values in water by diffusion sampling-cavity ring-down spectrometry. Combined with continuous salinity recordings, a data set of nearly 6,000 measurements was made at 30-s intervals during a 3-day voyage through the Great Barrier Reef Lagoon. Our results show that continuous shipboard measurement of ??¹⁸O/??D values provides additional discriminatory power for assessing water mass formation processes and histories. Precise identification of river plumes within the Great Barrier Reef Lagoon was only possible because unique ??¹⁸O/??D?Csalinity relationships of individual plumes were measured at high spatial and temporal resolution. The main advantage of this new technique is the ability to collect continuous, real-time isotope data at a small fraction of the cost of traditional isotope analysi s of discrete samples. Water ??¹⁸O and ??D values measured by diffusion sampling-cavity ring-down spectrometry and laboratory-based isotope ratio mass spectrometry have similar accuracy and precision.     

DEVELOPMENT OF FEDERAL RESERVE RIGHTS1

ABSTRACT: The concept that has been termed “Indian Rights to Water” is one manifestation of the area of federal reserved rights that is a major concern of states in arid regions. The federal reserved rights are those that are reserved in fact or by implication in federal actions, acts, reservations, and treaties. Federal actions include such things as navigation improvement and flood control projects. The Federal Court System, since the Civil War has been promulgating, developing, and protecting federal reserved water rights. The development of those rights can be traced from early cases through the landmark cases such as U.S. v. Rio Grande and Irrigation Co. (1899); Winters v. U.S. (1908) with the origin of the Winters' Doctrine of Indian Rights; Federal Power Commission v. Oregon, commonly called the Pelton Dam Case (1955); Arizona v. California (1963); U.S. v. District Court for Eagle County (1971); to existing suits on surface water sources such as that on appeal in regard to reserved federal water rights on the Truckee River. It can be shown that the federal position has been consistent through all the years in that the federal rights have been protected, expanded, developed, and preserved in a more or less predictable manner.     

Light quality effects on carbon metabolism and allocation in Gracilaria verrucosa

Under conditions of new nitrogen availability and low light intensities, light quality (blue, green, or red light) was not found to affect carbon fixation patterns into major metabolic fractions (total ethanol soluble, carbohydrate, and protein) in preconditioned nitrogen enriched or limited apical tips of Gracilaria verrucosa Papenfuss. Within the ethanol soluble fractions of both nitrogen enriched and limited tips, blue light treatment led to a greater percentage of ¹⁴ carbon in amino acids as compared to non-ninhydrin reactive metabolites. A lesser effect was observed with red light, and green light did not appear to stimulate amino acid synthesis appreciably. The low intensity blue light effect in G. verrucosa appears to be an enhancement of nonphotosynthetic carbon incorporation into amino acids, possibly through some form of the urea-ornithine cycle.Harbor Branch Foundation Contribution No. 237     

Changing patterns in aluminium production costs

The average cost of producing aluminium fell slightly in nominal terms between 1982 and 1992, and there has thus been a sharp fall in real terms. The average cost also shows a marked cyclical fluctuation during individual years, partly as a result of the feedback effect from final metal prices to the cost curve. Between 1985 and 1992, exchange rate fluctuations produced a sharp change in the relative position of US and European smelters. During the next eight years, costs are likely to rise gradually in real terms, reversing the historical trend, and unless the higher cost European smelters can cut costs significantly, they may face a bleak future.     

Functional burrow morphology of Biffarius arenosus (Decapoda: Callianassidae) from southern Australia

Burrows of the thalassinidean shrimp Biffarius arenosus (Poore, 1975) were investigated by in situ resin-casting on an intertidal sandflat in Western Port, southern Australia. Even though burrow casts exhibited interspecific variation, all had at least two openings, a U-shaped top and a series of tunnels and chambers. The space occupied by the burrows was deeper than it was wide; a maximal depth of 58 cm was recorded. Inhalant and exhalant shafts were restricted relative to tunnel diameter, and were often arranged in a multi-layered U-shape. Additional shafts branching from deeper sections of the burrows were occasionally observed. The main section of a burrow, extending from the base of the U, usually consisted of a downward spiral or an irregular spiral combined with some straight tunnel sections, all with a circular cross-section. The central spiral branched into further tunnels and chambers. Nearly all casts possessed peripheral chambers positioned either at the edges of horizontal lattices or in the deepest sections of the burrow. No evidence of plant material was found in peripheral chambers. Major burrow features were consistent with B. arenosus adopting a deposit-feeding trophic mode and collecting its food below the sediment surface. Received: 17 July 1998 / Accepted: 26 November 1998