Coastal Europe Research Articles

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Palaeowaters in Coastal Europe contains 17 contributions from an international array of authors. They discuss the history of groundwater evolution during the late Pleistocene in the coastal areas of Europe from the Baltic region to the Iberian peninsula and the Canary Islands. Geochemical and geophysical techniques for evaluating palaeowaters are reviewed. The focus of the book is on changes in the hydrogeological regime during the Quaternary and their impacts on groundwater movement and chemistry in European coastal aquifers. The work summarized in the papers was carried out by a partnership of European scientists under the auspices of the PALAEAUX project, an EC initiative. Researchers from the fields of hydrogeology, geochemistry, isotope hydrology and Quaternary studies attempted to reconstruct the most probable movement of groundwater in the study area over the past 100 000 years and its response to climatic events of global significance during the last glacial cycle. The results of this work, summarized in this volume, allow a better understanding of the water resources found at and near the coastlines of northern and western Europe. During times of lowered sea level, it appears that groundwaters were replenished to depths greater than occur at the present day. These pristine freshwater reserves are an irreplaceable asset. Their location at coastlines where populations and water demands are high and often seasonal means that they need careful management to avoid over-exploitation or contamination. The inevitable conflicts that this resource management creates are discussed. Palaeowaters in Coastal Europe: evolution of groundwater since the late Pleistocene will be of interest to Quarternary scientists, hydrogeologists, marine scientists engaged in coastal research and those involved in environmental science and the management of groundwater assests.

Weichselian palaeoclimate and palaeoenvironment in Europe: background for palaeogroundwater formation

Abstract A review is given of palaeoclimatic and palaeoenvironmental evidence across Europe for the Weichselian period relevant to interpreting the emplacement and circulation of groundwaters. In addition, this provides the background against which the evidence of past climates and environments contained in groundwaters in coastal areas of Europe, from the Baltic to the Atlantic Ocean may be compared. For much of the Weichselian, although significantly colder than at present, conditions were favourable for the recharge of groundwater, as shown, for example, by periods of speleothem growth. During the last glacial maximum (LGM) recharge is likely to have ceased over much of permafrost-covered Europe, although shallow groundwater recharge from meltwater (generated by the geothermal gradients) could have taken place beneath the ice where pressure relief through tunnel valleys may have occurred. Modern recharge could have started as early as 13 14 C ka BP , but probably interrupted by the Younger Dryas between 11 and 10 14 C ka BP . In the Baltic areas, ice-dammed lakes inhibited the start of the modern hydrogeological regimes until c. 10.3 14 C ka BP . Tundra conditions prevailed over most of ice-free southern Europe at the time of the LGM. At this time the area south of the Portuguese-Spanish border retained a generally warm and relatively humid climate due to the maintenance of warmer sea-surface temperatures derived from Atlantic Ocean circulation. For most of coastal Europe, however, the most significant impact on groundwater circulation is likely to have been the lowering of sea levels that drained large areas of the shelf, such as the North Sea and the English Channel, and also had a significant impact on the Atlantic coast of the Iberian Peninsula where the maximum lowering of up to 130 m would have been experienced. This, together with the general changes in climate, would also have reorganized the atmospheric chemistry over sites in Europe that is likely to be recorded in the groundwater’s chemical and isotopic signatures.

Biomass and productivity distributions and their variability in the Barents Sea

On the basis of results that largely have been derived from the Norwegian research programme Pro Mare (1984-1989), an overview of the distribution of biomass and productivity at different trophic levels of the pelagic Barents Sea ecosystem is presented, with comments on year-to-year and horizontal variations. Average biomasses for the whole Barents Sea and several years range from 2000 kg of carbon km −2 for each of Calanus spp. and phytoplankton stocks, down to 0.1 kg carbon km −2 for the polar bear population.Phytoplankton blooms that deplete the winter nutrients give rise locally to a “new” productivity of 40-50 g C m −2 . Areal differences, however, are pronounced in terms of annual productivity: the “new” fraction is more than twice as high in the southern (Atlantic) part of the Barents Sea as in the areas north of the oceanic Polar Front (90 vs. <40 g C m −2 yr −1 ), Wind-generated vertical mixing (in association with passing atmospheric depressions) and turbulence generated on and around banks in the southern part are crucial in accounting for this difference. In the northern half of the Barents Sea a pronounced upper layer stability caused by the supply of meltwater from seasonal ice retards mixing so that “new” production is small following the depletion of winter nutrients - high productivity is restricted to the 20-50 km wide ice edge bloom.Year-to-year variations in fish stocks are pronounced and have always been so - there exists no “ecological balance” in any meaningful sense. These variations are clearly related to the influx of Atlantic water to the Barents Sea (i.e. “warm” years are high-productive years) and, thus, ultimately to the same forcing factors that determine climate variations in coastal Europe. Thus, sound management may diminish the annual fluctuations in fish stock sizes but certainly cannot eradicate them.

Long-term changes of the surface air temperature in relation to solar inertial motion

The inertial motion of the Sun around the barycentre, or centre of mass, of the Solar System has been employed as the base in searching for possible influence of the Solar System as a whole on climatic processes, especially on the changes in surface air temperature. A basic cycle of about 180–200 years and its higher harmonics up to 30 years have been found in surface air temperature of central Europe since 1753, established from 13 continuous instrumental time series. These periods correspond to the periods of solar inertial motion. In the first half of the 19th century, when the solar motion was chaotic, this temperature was about 0.75°C lower than that in the 20th (1940–50) and the 18th (1760–70) centuries. The mentioned decades of long-term temperature maxima coincide with the central decades of the ordered (trefoil) motion of the Sun. The temperatures in coastal Europe have been found to have slightly different properties, especially on a long-time scale. The periods of 35–45 years are significantly pronounced in the coastal Europe temperature spectrum. The chaotic motion of the Sun in the next decades could decrease both the solar forcing and global surface air temperature.