CO2 partial pressure in Northeast Atlantic and adjacent shelf waters: Processes and seasonal variability

CO₂ partial pressure in surface water was measured in the Northeast Atlantic and in the Hebride Shelf/North Sea area during a cruise with R.V. Poseidon in June 1991. A mean p_CO2 of 303 μatm was found in the Atlantic between 50°N and 60°N. For an atmospheric CO₂ content of 357.5 ppm(v) this corresponds to a partial pressure difference of −55 μatm. This supports the view that the subarctic Atlantic is a significant sink within the CO₂ cycle between the ocean and the atmosphere. A comparison of our measurements with other data reveals that the p_CO2 distribution changes significantly during May/June. This explained by seasonal warming, CO₂ exchange with the atmosphere and biomass production. The contribution by each of these processes to the seasonal variations is calculated. It was found that during a plankton bloom the production of biomass is the dominating factor and may lower seawater p_CO2 by almost 100 μatm. The shelf areas are charactrized by strong p_CO2 gradients which are explained by water exchange with the Atlantic, temperature effects and biomass production.     

A shipbuilder's view of safety

Shipbuilders do not consider themselves leaders in furthering safety. There has been rapid growth in safety legislation but actual improvement has been modest. Casualty rates could most effectively be reduced in future by removing older ships. The responsibilities for safety in the longer term need consideration.     

EU maritime transport

The purpose of this paper is to summarize the European maritime transport policy within the context of maritime politics at large. At the outset the legal framework conditions and supportive instruments for the shipping and port industries are presented. Against the background of recent accidents at sea, such as the sinking of ERIKA and PRESTIGE, the EU legislation on maritime safety is of particular interest as it is both complex and rapid in reaction to environmental needs and political pressure. Finally, the sensible relationship between the EU as a regional organization and the IMO as “the competent international organization” is discussed with a view to reconcile possible rivalry and to suggest a complementary cooperation between the two organizations.     

Crystallographic structure of sea ice along a salinity gradient and environmental control of microalgae in the brine cells

Duplicate ice cores were taken in southeastern Hudson Bay (Canadian Arctic), at 8 stations along a transect, from the mouth of the Great Whale River to saline waters 25 km offshore. One core from each station was cut into 10-cm sections, which were melted at room temperature for determinations of salinity, nutrients, algal pigments and taxonomic composition of the microalgal assemblages. On the second core, thin sections were cut every 2 cm to optically determine the ratio of brine/gas pockets to the total sections. Relative volumes of brine in melted samples were computed from the observed ratios and calculated values, and used to convert per unit brine volume the concentrations of pigments, nutrients and algal cells, initially measured per unit volume of melted sample.Salinity of the melted samples indicate the presence of freshwater beneath the sea ice close to shore throughout the growth season, and the vertical salinity profiles suggest intermittent intrusions of freshwater. Nutrient concentrations in the brine were high, suggesting that microalgae in the brine cells were generally not nutrient limited. Concentrations of ice algae in the brine cells reached relatively high values, that are often of the same order as those reported for eutrophic marine waters. Statistical analyses identified the rate of ice growth as the most important factor controlling the vertical and horizontal distributions of algal biomass and taxonomic composition in the sea ice, along the salinity gradient. Higher biomasses were generally associated with slower ice growth and also possibly lower grazing activity. In addition, the rate of ice growth influenced the distribution of microalgal assemblages, with nitrogen limitation potentially playing a secondary role in some instances.     

Shipping and the competitive advantage of nations: the role of international ship registers

This paper argues that the creation of international ship registries by traditional maritime countries will not sufficient to halt the decline of their fleets. Over the last two decades shipping has undergone profound restructuring, characterized by a trend towards globalization and a search for a more efficient factor input combination. While shipowners from OECD countries have relied increasingly on flags of convenience, new maritime countries, particularly from Pacific Asia, have emerged, taking advantage of low-cost inputs and supportive national national environments. In the late 1980s the traditional maritime countries responded to the challenge by introducing international ship resistries. The Norwegian International Ship Registry is the most liberal and has the greatest success. Other new registries have limited impact. It appears that an international ship registry per seis not sufficient to reverse declining national fleets.     

Currency adjustment factors

The manner in which CAFs have been applied to cargo carried by lines appears to be both arbitrary and secretive. This note intends to give some clarification as to how the CAF is calculated and the manner in which it is applied.

The operation of the two methods, i.e. the monthly review and the radical review, is merely a device which enables conferences to adjust effective charges so as to leave lines without a loss in real revenue, although minor losses and gains will be inevitable as the operation of the CAFs take time to be implemented.

Finally it is hoped to point out the volatilc nature of CAF changes impinges upon the uncertainty of lines' costs.     

A statistical approach to the traveling salesman problem

A statistical approach is shown to be adaptable to the N-city traveling salesman problem by considering route distances to be random variables which are continuous and normally distributed. A solution to the shortest route distance and path can be approximated by utilizing a Monte Carlo simulation to obtain a representative sample of possible journeys. The approach involves recursive statistical inference which is used to select next-city visits leading to the most probable minimum route path. A statistical selection of the minimum route path is computationally efficient and computer run time increases in proportion to the square of the number of cities as opposed to an (N - 1)! increase for a deterministic approach. The accuracy of the statistical approach is directly proportional to the number of Monte Carlo simulations.     

Heavy goods vehicle taxation in the United Kingdom

Heavy goods vehicle taxation has been the subject of considerable debate in U.K. over the past 15 years. There have been a number of attempts to relate the taxes paid by heavy goods vehicles to the public costs incurred to provide road track for their use. This paper reviews critically the position taken in the last public account of allocation procedures and also outlines recent modifications to the approach. It is suggested that the allocation of public costs is sensitive to some of the assumptions made and that this may result in an over-estimation of the costs associated with road haulage activities. A number of comparative calculations are made using data from both 1975/76 and more recent years to examine this hypothesis.