Ref ID : 3204
Eike Hartwig; [Die Ciliaten des Gezeiten-Sandstrandes der Nordseeinsel Sylt II. Okologie] (The ciliates of the tidal beach on the island of Sylt (North Sea). II. Ecology). Mikrofauna Meeresboden 21:1-171, 1973
Reprint
In File
Notes
The zonation of the interstitial ciliates in different eulittoral beaches of the island of Sylt as well as their annual fluctuations were studied from July 1968 to March 1970. For quantitative studies, regular series of samples were taken in the beach in front of the Litoralstation List; further beaches were sampled once. In the sand flat of a medium wave-beaten beach ("mittel-lotische"). The population density reaches values of more than 1 million animals per m2 related on 10 cm sediment depth. There is only an unimportant difference in the number of individuals between the eulittoral part of the wadden area and the sublittoral. Vertically the number of animals decreases and reaches a minimum at 30 cm in the substratum. The average value of the population density of the sand flat is 16 times higher than that of the beach slope. The beach slope has lower density values; in its middle part a maximum of 800,000 animals per m2 related on about 60 cm sediment depth were found. Towards the average high water level a rapid decrease of population density can be observed. In vertical direction there are large numbers of animals in the zone of damp sand and low ones in the subsoil water; the maximum relation in point of the numbers of individuals is in the middle beach slope 23 to 1. In the course of the year water temperature and population density are clearly correlated in the sand flat. The lowest number of individuals is found in winter, the highest in summer before the water temperature reaches its maximum. In the beach slope there is no clear correlation between temperature and density. Vertical zonations in the course of the year are found. In the sand flat in summer up to 97% of all individuals occur in the surface layers from 0 to 10 cm; in winter the sediment layer from 10 to 20 cm contains 34% of all animals. Within the beach slope in winter the fauna is moving away from the upper layers of substratum with low temperatures. In the wadden area of a "mittel-lotische" beach the individual numbers of ciliates are about 3 times higher than the values of Micro-Metazoa; the number of Metazoa in the beach slope is more than 7 times higher than that of the ciliates. The dispersal and the annual fluctuation of 30 single species are described. Most of them occupy a horizontally and vertically defined area of settlement of the beach. The wadden areas are characterized by Blepharisma clarissimum f. arenicola, Ciliofaurea mirabilis, Coleps pulcher, C. similis, C. spiralis, Condylostoma areanrium, C. fjeldi, C. remanei, Diophrys scutum, Discocephalus ehrenbergi, Epiclintes ambiguus, Geleia nigriceps, Helicoprorodon gigas, Holosticha discocephalus, Loxophyllum levigatum, L. vermiforme, Paraspathidium fuscum, Peritromus faurei, Pleuronema marinum, Trachelostyla caudata, T. pediculiformis, Uronychia transfuga, Urostrongylum caudatum. Mainly in the area where the beach changes from sand flat to beach slope ("Strandknick") Euplotes eurystomus and Pseudoprorodon arenicola are found. Coleps tesselatus, Diophrys multinucleatum, Discocephalus ehrenbergi, Loxophyllum trichocystum, Swedmarkia arenicola occur in the lower and middle part of the beach slope, while Remanella unirugosa is a characteristic inhabitant of the upper beach slope. Vertical distribution in the course of the year for Coleps similis, Epiclintes ambiguus, Paraspathidium fuscum, Trachelostyla pediculiformis, Urostrongylum caudatum in the sand flat and for Dinophrys multinucleata, Discocephalus ehrenbergi in the beach slope are described. In qualitative respect the interstitial ciliate fauna is equally favoured at the "mittel-lotische" beaches; about 10 species against 3 to 4 at strongly wave-beaten beach slopes ("stark lotische Sandhange") and 28 species at the sand flats against 2 to11 at mud flats. Turbulence is regarded for the lacking of many species at the "stark lotische" beach; at the slightly wave-beaten beach ("schwach lotische") under average wave action combined with the minor oxygen availability is regarded as the decisive factor. Within the wadden area of an eulittoral tidal beach the vertically decreasing oxygen supply and the increasing reducing conditions as well as the variations of temperature are regarded as decisive factors; within the beach slope the population density is determined by the variations of pore water content and salinity as well as the oxygen availability and the variations of temperature.