Swedish Fjord Research Articles

Succession in Benthic Macrofauna in a Swedish Fjord Subsequent to the Closure of a Sulphite Pulp Mill

Quantitative sampling of the fauna was made in 1971 and 1972 to complement previous data about the faunal recovery after the cessation of the sulphite pulp mill in 1966. In 1972 the succession had approached a final phase in which the fauna had regained a composition similar to that found forty years earlier. The benthic faunal increment, expressed as dry weight, in Saltkallefjord over the period 1968-71 was roughly estimated to 20 per cent and the yearly production to 70-80 tonnes on this 4.4 km2 area. Different indices have been used to describe the communities and the diversity. The succession showed a logistic pattern similar to population growth curves.

Benthic Faunal Recovery in a Swedish Fjord Following the Closure of a Sulphite Pulp Mill

During 1968-70, the recovery of the benthic macrofauna was investigated at 53 stations in Saltkallefjord, an inner branch of Gullmarsfjord on the west coast of Sweden. Physico-chemical analyses have shown that the water quality in Saltkallefjord improved as a result of reduced waste water discharge subsequent to discontinuance of production of sulphite pulp in 1966. After 1968, the benthic macrofauna has colonized fjord areas which earlier in the 1960's were azoic, or occupied by a poor fauna only. During May-October 1969, a successive monthly increase of the number of species appeared in these areas. Classification of some species in the succession is subject to discussion.

Internal Waves in the Sea

I AM just reading with great interest the important and excellent work by H. U. Sverdrup, M. W. Johnson and R. H. Fleming, "The Oceans: their Physics, Chemistry and General Biology" [Prentice-Hall, Inc., New York, 1942. See p. 652 of this issue of Nature]. I should like to direct attention to a lapse which I am rather anxious to have pointed out. On page 592 the first observation of internal waves in the sea is attributed to Helland-Hansen and Nansen. The fact is that such waves were discovered in the Great Belt two years before by the nestor of Swedish oceanographers1, the late Otto Pettersson—well known as the originator of the international organization for marine research—and he also proved their tidal periodicity. Furthermore, on page 600 reference is incidentally made to observations of internal waves in a Swedish fjord which Otto Pettersson is said to have carried out "during 2 months of 1909". As a matter of fact, these observations were continued over several years2, and—although particular theoretical conclusions which Pettersson inferred are open to serious criticism—the observations themselves are in their method by far the most exhaustive ever made.