Bengt-Owe Jansson

Economic Growth, Carrying Capacity, and the Environment

Nat iona l and international economic policy has usually ignored the environment. In areas where the environment is beginning to impinge on policy, as in the General Agreement on Tariffs and Trade (GATT) and the North American Free Trade Agreement (NAFTA), it remains a tangential concern, and the presumption is often made that economic growth and economic liberalization (including the liberalization of intemational trade) are, in some sense, good for the environment. This notion has meant that economy-wide policy reforms designed to promote growth and liberalization have been encouraged with little regard to their environmental consequences, presumably on the assumption that these consequences would either take care of themselves or could be dealt with separately. In this article we discuss the relation between economic growth and environmental quality, and the link between economic activity and the carrying capacity and resilience of the environment (1).

Resilience in natural and socioeconomic systems

We, as a society, find ourselves confronted with a spectrum of potentially catastrophic and irreversible environmental problems, for which conventional approaches will not suffice in providing solutions. These problems are characterized, above all, by their unpredictability. This means that surprise is to be expected, and that sudden qualitative shifts in dynamics present serious problems for management. In general, it is difficult to detect strong signals of change early enough to motivate effective solutions, or even to develop scientific consensus on a time scale rapid enough to allow effective solution. Furthermore, such signals, even when detected, are likely to be displaced in space or sector from the source, so that the motivation for action is small. Conventional market mechanisms thus will be inadequate to address these challenges.

Quantitative and experimental studies of the interstitial fauna in four Swedish sandy beaches

Abstract The distribution of the interstitial metazoans was studied quantitatively in four Swedish beaches, three in the Baltic and one in the Skagerrak. As many as 1.5 × 106 individuals per m2 were found (Asko beach, south of Stockholm). Temperature, salinity, oxygen concentration and availability, grain size, water contents and organic material were measured in connection with the sampling. The oligochaetes, turbellarians and harpacticoids showed different degrees of submergence landwards in the beaches with the oligochaetes near the sand surface, followed by the turbellarians and - deepest down - the harpacticoids. This may be explained by a difference in dependence on water-saturation: the oligochaetes are more or less terrestrial, and the turbellarians can move in a thinner water film than can the harpacticoids. A correlation between the distribution of oxygen and certain species was found in several cases. The microbial film on the sand grains is pointed out as an important food-source and the utili...

On the vertical distribution of the microfauna in the sediments of a brackish-water beach

Abstract The vertical distribution of the microfauna in the sediments of the water-covered parts of a beach on the island of Asko (Baltic Sea) was investigated by quantitative methods. Factors such as temperature, salinity, grain size, oxygen, pH and redox potential were measured at various depths in the sediment. The members of the microfauna, especially the ciliates, showed a characteristic vertical zonation. The vertical extension of the species could be correlated with the redox potential of the sediment, especially the depth of the redox-discontinuity layer. The possible reasons for this are discussed, the most important probably being the type of bacterial flora characteristic of different electrode potentials. A quantitative estimate on the different taxonomic groups of the microfauna in the investigated area is given. Ciliates were most numerous (100–480 specimens per ems) while the most important metazoan groups (turbellarians, nematodes, rotatorians, oligochaetes and harpacticoids) each were rep...

The availability of oxygen for the interstitial fauna of sandy beaches

The oxygen conditions in four Swedish sandy beaches, three in the Baltic and one in the North Sea, have been investigated at various times during the year. Measurements have been made of both oxygen concentration and oxygen diffusion rate (ODR), the latter with a stationary platinum microelectrode technique, at different distances from the water-line and at various depths in the sand. Laterally along the beach, i.e. along a transect parallel to the water-edge, the conditions at corresponding depths are very similar. Horizontally and vertically, however, the distribution of oxygen shows no clear trend except at the most seaward part of the beach which is the best oxygenated. Even in winter the deep unfrozen strata, covered by thick layers of frost, show clear, though low, ODR values. The availability of oxygen is strongly governed by the physical and chemical properties of the sand: porosity, permeability, percentage air volume, and maxima appear at various depths in the sand. The flow of the interstitial water in the beach is of great importance; the role of waves in determining the availability of oxygen is demonstrated by in situ measurements of ODR. Each separate wave greatly increases the availability in adjacent areas. The dynamics of this process has been analyzed in laboratory experiments, which show the effects of separate drops of water and of changing ground-water pressure upon the oxygen availability of the pore-water. Two examples of faunal distribution in the field along a concentration gradient of oxygen are given. The fauna, consisting of turbellarians and nematodes, was in both cases concentrated in the best oxygenated layers.

On the diurnal activity of some littoral peracarid crustaceans in the Baltic Sea

Abstract A diurnal periodicity in the activity of some peracarids inhabiting seaweeds has been investigated at the Asko Laboratory, the northern Baltic Sea during June–September 1965. The animals were caught semi-quantitatively by sweeping a net over a known distance at the water surface above the algal belts every 3 h. Neomysis vulgaris, Praunus spp., and Idothea spp. were all taken almost exclusively in the catches between 21.00 h and 03.00 h. Of the chief environmental parameters only illumination showed a corresponding variation. Field and laboratory experiments on the influence of light were carried out with Gammarus oceanicus, Idothea baltica and Idothea chelipes. A single specimen per dish was put in Petri dishes containing habitat water and a piece of Fucus and the activity was noted every other hour. In experiments under natural light conditions the activity of Gammarus oceanicus increased significantly when light intensity dropped to a few lux and fell again when values of a few thousand lux were attained. Idothea baltica and Idothea chelipes showed a distinct increase in swimming activity when light intensities fell below one lux and the period of inactivity began at 400–800 lux. In experiments with successive periods of constant dark or constant light all three species were inactive in light, active in dark. The close correlation between field and laboratory responses was further confirmed by light-alternative experiments with Gammarus oceanicus and Idothea baltica: of the two alternatives offered namely 2500–3000 lux and dark, nearly all the 10 individuals of both species chose the dark. This relationship between the activity of the animals and illumination may be of survival value in the presence of a large number of predators, especially fish. Night is very important as being most favourable to large scale dispersal.

Vertical and horizontal distribution of the metazoan microfauna and of some physical factors in a sandy beach in the northern part of the Öresund

Abstract During a summer course on marine microfauna the vertical and horizontal distribution of the interstitial metazoan fauna and of some physical and chemical factors (salinity, temperature, oxygen, water contents) were studied above the water line in a sandy beach in the northern part of the Oresund. Seventy-one species of micro-metazoans could be recognized in the beach. Fourty-three of these were nematodes. This group was also quantitatively dominating: out of a total of 2874 sampled individuals, 1584 were nematodes. The horizontal and vertical distribution of a number of species could be correlated with the distribution of salinity, water contents and oxygen. In the case of some of the oligochaete and harpacticoid species the interpretations of the distributions could be supported by preference and tolerance experiments described in the literature.

Diurnal and annual variations of temperature and salinity of interstitial water in sandy beaches

Abstract The dynamics of temperature and salinity was studied at four beaches situated along the Swedish East and West Coast, representing salinities from 7 to 22 ‰. Diurnal and seasonal temperature variations were registered at various depths in the beach. The maximum diurnal amplitude was measured in May and amounted to 37.2°C with a maximum temperature at the dry sand surface of 43° C. In winter the sand is frozen often down to 60–70 cm depth, but in spite of low air temperatures the values below a few cm depth will not fall below —2 to —3°C. The greatest diurnal amplitudes and vertical gradients are attained in spring. The pronounced horizontal and vertical gradients in summer decrease towards autumn when, however, during a short period with night frost, great diurnal amplitudes again occur. Changes in salinity chiefly take place along a horizontal gradient at right angles to the waters edge. Inside a sea of 7‰. S freshwater could sometimes be encountered at 0.8 m distance from the water-line. The ve...

Quantitative investigations of the Baltic Fucus belt macrofauna

Abstract A remote operating device for obtaining quantitative samples of bushy algae is described. An algal plant, fixed in the middle of a collapsible cage is used as a natural trap. Lines operating from the sea surface ensure a rapid enclosure of the alga which after a weeks exposure has received a natural fauna. The device has worked quite satisfactorily for a period of more than two years of continuous exposure with a monthly sampling of the Baltic fauna. An annual maximum of animals of around 600 specimens per 100 g dry Fucus occurs in November, dominated by the crustaceans Idatea and Gammarus and the molluscs Hydrobia, Theadaxus and Cardium. The annual minimum occurs in January with around 100 specimens. A more frequent sampling has shown that especially the molluscs and Gammarus invade the initially empty Fucus plant very rapidly.

The Baltic Basin Case Study—towards a sustainable Baltic Europe

Abstract Four watersheds, each characterized by a major resource use were selected for the study: The Vistula River in Poland—agriculture; the Dalalven River in Sweden—forestry; the Archipelago Sea in Sweden, Finland, Estonia—tourism; and the Lake Peipsi in Estonia/Russia—fisheries/agriculture. The main objective was to examine the reactions of particular ecosystems within the Baltic Sea drainage area, and to assess sustainability conditions on the regional level. The degree of sustainability and impact on the Baltic Sea were investigated through workshops and seminars in the areas. Overviews of environmental and socio-economic conditions were succinctly summarized in commissioned papers. Interventions by and discussions with scholars, sector experts, administrators and stakeholders of the various sites laid the foundation for conceptualizing the interaction of natural and human forces for each case. The project was able to draw quite a number of conclusions, summarized as the following lessons learnt. In the Vistula Region, nutrient emissions have levelled off but shortage of freshwater is critical. Forestry in the Dalalven watershed is largely environmental-friendly, except for fragmentation of the landscape and its negative impact on biodiversity. In the Archipelago area a former low-energy community has been replaced by a leisure time society. Different types of tourism is developing, but despite this variety, an improved integration of ecological properties with socio-economic patterns is required in order to build a sustainable, living Archipelago. The lake Peipsi basin and the surrounding area suffer both from problems of resource management and economic backwardness. Parts of the local economy has lost access to the one time large Soviet market, although the Estonian side has apparently benefited from present economic growth. To cope with the division of the lake, a regime for trans-national management is unfolding. It is based on both informal and, to an increasing extent, agreed professional contacts. Networks of engaged people were in all sites a resource for and promoter of the sustainability path. In order to succeed and to maintain the zeal, they need strong institutional support and common goals. Public programmes in the Baltic, ie. the work of the Helsinki Commission and Baltic Agenda 21, have developed instruments to enhance sustainability beneficial for the management of these watersheds. But critical tasks remain to be done in developing a shared understanding of ways to improve management of ecosystems with social factors.