Plankton community diversity from bacteria to copepods in bloom and non-bloom conditions in the Celtic Sea in spring

The plankton community composition comprising heterotrophic bacteria, pro-/eukaryotes, heterotrophic nanoflagellates, microzooplankton and mesozooplankton was assessed during the spring bloom and at non-bloom stations in the English Channel and Celtic Sea between 6 and 12 April 2002. Non-bloom sites were characterised by a dominance of pro-/eukaryotic phytoplankton <20 μm, higher abundance of heterotrophic nanoflagellates, microzooplankton standing stocks ranging between 60 and 380 mg C m⁻², lower mesozooplankton diversity and copepod abundance of between 760 and 2600 ind m⁻³. Within the bloom, the phytoplankton community was typically dominated by larger cells with low abundance of pro-/eukaryotes. Heterotrophic nanoflagellate cell bio-volume decreased leading to a reduction in biomass whereas microzooplankton biomass increased (360–1500 mg C m⁻²) due to an increase in cell bio-volume and copepod abundance ranged between 1400 and 3800 ind m⁻³. Mesozooplankton diversity increased with an increase in productivity. Relationships between the plankton community and environmental data were examined using multivariate statistics and these highlighted significant differences in the abiotic variables, the pro-/eukaryotic phytoplankton communities, heterotrophic nanoflagellate, microzooplankton and total zooplankton communities between the bloom and non-bloom sites. The variables which best described variation in the microzooplankton community were temperature and silicate. The spatial variation in zooplankton diversity was best explained by temperature. This study provides an insight into the changes that occur between trophic levels within the plankton in response to the spring bloom in this area.     

Perceptions and costs of seal impacts on Atlantic salmon fisheries in the Moray Firth,Scotland: Implications for the adaptive co-management of seal-fishery conflict

The Moray Firth Seal Management Plan (MFSMP) was introduced in Scotland in 2005 as a pilot for resolving conflict between Atlantic salmon fisheries and conservation imperatives for protected harbour and grey seals. This adaptive co-management model is now being applied nationally through the Marine (Scotland) Act (2010). However, no information exists on salmon fishery stakeholders’ perceptions of seal predation impacts and related costs, which could influence the success of the MFSMP and other similar initiatives. In 2006 a questionnaire survey of the 95 salmon rod fisheries in seven major Moray Firth rivers was undertaken, and all 20 active salmon netting stations in the Firth. Forty-five fishery owners, 39 ghillies, 120 anglers and 11 netsmen (representing 17 netting stations) responded. The majority (81%) believed that seals had a significant or moderate impact on stocks and catches, 77% believed that all seals were responsible and 47% supported seal culling. Seals were sighted by 38% of rod fisheries, and 18% lost angler days from seal interference. Overall, 0.2% of total reported angler days were lost annually. The estimated direct cost of seal interference for responding rod fisheries was £14,960 annum⁻¹, and losses of catches and damage to nets was £16,500 annum⁻¹ for responding netsmen. Stakeholders’ perceptions were largely inconsistent with their low direct costs and the aims of the MFSMP. Possible reasons for this are discussed, and implications for the governance of future adaptive co-management initiatives for seal-fishery conflict.     

Water quality impacts from on-site waste disposal systems to coastal areas through groundwater discharge

This report summarizes research studies linking on-site waste disposal systems (OSDS) to pathogen and nutrient concentrations in groundwater with the potential to impact coastal embayments. Few studies connect OSDS to coastal water quality. Most studies examined pathogen and nutrient impacts to groundwater and omitted estimations of contaminants discharged to surface water. The majority of studies focused on nitrogen, with little information on pathogens and even less on phosphorus. Nitrogen discharged from OSDS poses the greatest threat to water quality. Vertical distance of septic tank infiltration system from the water table, septic system design, and siting remain the key components in minimizing potential impacts from OSDS for control of both pathogens and nutrients. The most comprehensive information connecting nutrient contributions from OSDS to surface water quality was the study conducted on Buttermilk Bay in Massachusetts where 74% of nitrogen to the bay was attributed to onsite disposal systems. In conclusion, further studies on the viability and transport of pathogens and nutrients through the groundwater aquifer and across the groundwater/surface-water interface are needed. Additional research on the importance of septic system design on the availability of contaminants to groundwater as well as the minimum distance between the septic system and water table necessary to protect groundwater are also indicated.     

Measurements of formaldehyde in the troposphere by tunable diode laser absorption spectroscopy

Measurements of formaldehyde, HCHO, using tunable diode laser abssrption spectroscopy (TDLAS) are reported for four sites in North America. The TDLAS apparatus and its application to these measurements is described. Detection limits of ca. 0.25 ppbv were obtained with a three-minute time resolution. Two distinct types of diurnal behaviour were observed: in the absence of local pollution sources the HCHO diurnal variation was weak and HCHO is not lost during the night. We conclude that the lifetime of HCHO with respect to dry deposition was greater than 50 h at the least-polluted site. At sites downwind of pollution sources, the HCHO peaks near noon and declines in the afternoon. At the least-polluted location, the most probable value for HCHO was 0.25–0.5 ppbv, while hourly averaged values up to 12 ppbv were observed at the other locations.     

Fundamental issues in quantitative estimation of mineral resources

Several issues considered to be fundamental in quantitative estimation of mineral resources and selection of mineral targets are addressed. Integration of multiple data sets, either by experts or by statistical methods, has become a common practice in estimation of mineral potential. Several major problems in data integration must be solved to significantly improve mineral resource estimation. Issues related to randomness of mineral endowment, basic statistical tools, exceptionalness of ore, and economic truncation and translation are discussed in the first part of the article. A number of important technical problems in data integration are also identified; they include data compilation, information enhancement, information synthesis, and target selection.     

An upper limit on the HCl near-surface mixing ratio over the Atlantic measured using TDLAS

A study of the gas phase mixing ratio of hydrochloric acid was made during the 1988 Polarstern expedition using tunable diode laser absorption spectroscopy (TDLAS). The measurements were made 22 m above sea level at 28° N, 30° W. The signal-to-noise ratio was unity for <50 pptv HCl, but because of wall effects in the sampling system, only an upper limit for the HCl mixing ratio of <250 pptv can be stated.     

The latest trend tracing model for projection of mineral demand

A new method for short- and long-term forecasting of mineral commodities based upon historical data is developed. The method, referred to as the latest trend tracing (LTT) model, is constructed as a weighting and adaptive approach based on a general linear model. The LTT model considers the functions of data location and statistical behavior. The newest data receive the largest weights, whereas the older data are given smaller weights. The LTT model is performed by an iterative algorithm. The data set is successively partitioned into training and testing subsets. Each LTT model is estimated and tested for each partition. The updated estimates are then synthesized to produce the final estimates based upon the data locations and estimation variances. The LTT model is demonstrated on two real case studies, one on the projection of U.S. aluminum consumption and the other on the forecasting of U.S. copper consumption.     

Three nonparametric techniques for the optimum discretization of quantitative geological variables

Three nonparametric techniques for the optimum discretization of quantitative geological features are proposed and demonstrated. The three methods are: isolated weight, entropy information, and rank correlation. Optimum discretization plays important roles in solutions to the following geoscience problems: (1) signal/noise separation and delineation of meaningful anomalies and other geofields related to mineral targets; (2) selection of those geological variables that explain variations in mineral resources; (3) determination of the best subintervals of values for a variable with respect to mineralization; (4) enhancement of certain complex and concealed information of a geofeature about its correlation with magnitude of mineralization; and (5) unification of diverse geodata so that these data can be integrated and analyzed.