Etude expérimentale de la ponte chez trois espèces de copépodes pélagiques (Centropages typicus,Acartia clausi et Temora stylifera)

Egg-laying of 3 common copepod species from the Gulf of Marseilles (Centropages typicus Kröyer, Acatia clausi Giesbrecht, Temora stylifera Dana) has been studied under various trophic conditions, at different periods of the year. The role of phytoplankton abundance in the induction and importance of egg-laying is indicated. The specific quality of the algal suspension used for feeding affected also fertility. A seasonal variation in the importance of egg-laying is established. Some observations are made on egg deposition and development.     

Les Silicoflagellés du Golfe de Marseille

A study of the Silicoflagellates of the Gulf of Marseilles was carried out using water samples collected during three years (1962, 1963 and 1964), at two stations, in 5, 20, 40 and 60 m water depths, respectively. Dictyocha speculum Ehr. was not often seen, whereas D. fibula Ehr. was present all year round. The main forms are D. fibula typica and D. f. var. messanensis (Haeckel) Lemm. The annual cycle of D. fibula, a very constant one, consists of a period of main development during winter and spring, followed by a period of scarcity during summer and autumn. This cycle is very similar to that described by Nival (1965) in Villefranche sur mer. It seems that in Marseilles, as in Villefranche, the development of D. fibula is limited by temperatures over 15 °C. In summer, D. fibula sinks to deeper and colder waters.     

Marine fungi deteriorating chitin of hydrozoa and keratin-like annelid tubes

Higher marine fungi were found for the first time as degraders of chitinous exoskeletons of hydrozoa and of keratinous (?) tubes of annelids. Collections were made in several locations of the Atlantic and Pacific Oceans. Fruiting bodies and hyphae of the ascomycete Abyssomyces hydrozoicus Kohlm. occurred on hydrozoa at a depth of 631 to 641 m near the South Orkney Islands. Sterile mycelia, some of them resembling Dictyonema zoophytarum Reinsch, were collected on hydrozoa on the North Carolina coast, and offshore at a depth of 46 to 73 m. Tubes of the polychaete Chaetopterus variopedatus (Renier) washed ashore in California contained ascocarps and mycelia of Lulworthia sp. Hyphal growth on and in the animal tubes is described and illustrated.     

Fitting a parabola to growth data of fishes and some applications to fisheries

Denoting a fish length or weight at age t by X _t , a reference age by t _m , and the corresponding fish length or weight by X _m , the relation between age and length or weight may be described by a parabola as follows: $$\left| {X_t } \right. - X_m \left| = \right.a + b(\left| {t - t_m } \right.\left| ) \right. + c(\left| t \right. - t_m \left| ) \right.^2$$ or $$X_t = A + b(\left| {t - t_m } \right.\left| ) \right. + c(\left| t \right. - t_m \left| ) \right.^2$$ where a, b and c are constants. Each of the above Eqs. describes one curve at ages older than t _m and another one at younger ages, which is made possible by means of the transformation of t to (|t-t _m |). In 2 cases out of 10, the parabola takes the form of a cubic equation. Evidence is given that, as the growth data become fewer, the better fit of the parabola or cubic equation will probably be less in comparison to the von Bertalanffy equation (1938, 1949) as developed by Beverton and Holt (1957) and the power-growth equation (Rafail, 1971), and vice versa. This growth equation is used to derive models for estimating the optimum age and yield for fish populations.     

Einsatz der Hasse-Diagrammtechnik zur vergleichenden Datenanalyse von Biomarkerantworten und ökotoxikologischen Tests

Ecotoxicological investigations focus on biological systems and their response to chemically induced stress. Experimental techniques are much more developed than deterministic dynamic modelling. In this methodological contribution a technique is presented, based on lattice theory. This technique, also calledHasse diagram technique, allows data analysis with respect to comparative evaluation. Hasse diagrams are used

? to suggest a possible measure of microbial diversity,

? to analyze dependencies between phospholipid fatty acids and simple geochemical parameters on an ordinal scale and

? to visualise complex results of interactions of humic substances with xenobiotics.

     

Microdistribution d'un Pontellidae dans le Golfe de Marseille: Anomalocera patersoni

Zooplankton samples collected in the Gulf of Marseille with a system of 10 horizontal nets permitted the study of the stratification in the upper first meter. The pontellid copepod Anomalocera patersoni Templeton is a very typical species in this near-surface biotope. Its occurrence in the uppermost water layer (0 to 10 cm) is denser than in the others. This copepod shows the greatest decrease of population density between the first and the second layer, and becomes rare from 40 to 100 cm.     

Reproduction asexuée chez Phoronis psammophila

Reproduction by transverse fission in Phoronis psammophila Cori occurs in the muscular region of the trunk and divides the animal in two. The posterior fragment regenerates an anterior end, as described by Emig (1972), but completion of the first stages requires longer. The regenerating oesophagus fuses with the epidermis, and the mouth originates by intraepithelial invagination followed by epidermal invagination. The anterior fragment regenerates an ampulla (posterior end) principally by morphallaxis. Organogenesis concerns only the stomach and stomachal blood-sinus. The regenerating stomach (endodermal) and oesophagus (ectodermal) are obtained by differentiation of the prestomacal cells. Asexual reproduction in P. psammophila is a means of rapid numerical increase in the population.     

Evaluation de la matière organique vivante dans les eaux marines par la mesure de l'adénosine triphosphate

Quantitative determination of living organic matter (micro-organisms) in the ocean were made using the adenosine triphosphate (ATP) assay. Strehler and Totter's (1952) method was used. A simple apparatus recorded the photons emitted from the very beginning of the photochemical reaction; the assay is specific for ATP but enzymes present in Photynus pyralis suspension may create errors. The sea-water ATP values in Marseilles Bay range between 2.10^-2 and 80.10^-2 mg per m³. An offshore profile of the Mediterranean Sea, near Toulon, gives values around 10^-3 mg/m³. Protein assays have been made on the same samples. The differences existing between certain values in the series are attributed to inert particles.     

Remarques sur la systématique des Phoronidea X. Notes sur l'écologie,la morphologie et la taxonomie de Phoronis ijimaï et de P. vancouverensis

The ecology, morphology and taxonomy of Phoronis ijimaï Oka, 1897 and P. vancouverensis Pixell, 1912 have been studied in some detail and are compared with those of P. hippocrepia. P. vancouverensis is considered as a synonym of P. ijimaï (which would be demanded by the law of priority). P. ijimaï must be considered as a distinct species and not incorporated into P. hippocrepia.     

Sur l'association de Phoronis australis (Phoronida) avec Cerianthus maua (Ceriantharia) dans les zones récifales de Madagascar

The occurrence of Phoronis australis Haswell in the tubewalls of Cerianthus maua Carlgren at Madagascar allows us to describe the taxonomic characteristics of both species and to deal with ecological aspects of the bottoms colonized. The tube wall of C. maua may be divided into 5 distinct layers. P. australis builds his own tube (whose position in the cerianthid-tube is studied): the ampulla always occurs in the fourth layer, and the lophophore projects externally. The Phoronis australis-Cerianthus maua association can be defined as an inquilinism on the basis of three relations: substrate, feeding, protection (C. maua probably obtains no advantage from this association).     

Der Lebenszyklus vonAcrosiphonia grandis (Acrosiphoniales,Chlorophyta)

Acrosiphonia granlis Kjellm, is well characterized by its long rows of intercalary fertile cells. Material obtained from Iceland proved to be very interesting by reason of its peculiar life history. The zygote develops into a codiolum-like stage, which grows directly into anAcrosiphonia thallus at an age of some 20 days without formation of swarmers. The same features have recently been demonstrated byJónsson (1967) in an Icelandic species, identified by him asAcrosiphonia sonderi. From his specimensJónsson described facultative caryogamy, ascertained by him formerly in otherAcrosiphonia species: its absence induces the above-mentioned development, giving rise to a generation of mictohaplonticAcrosiphonia. In contrast, true zygotes of “Acrosiphonia sonderi” develop into fertile codiolum cells, reproducing themselves by biflagellate swarmers. InA. grandis, facultative caryogamy has not been observed and nuclear fusion occurs in all zygotes. Codiolum stages never produced swarmers. The life history ofA. grandis represents an intermediate type between the heteromorphic cycle of species such asA. spinescens (including a true codiolumsporophyte), and the isomorphic life history ofA. arcta, where the zygote develops directly into the filamentous plant.     

Die Symbiose zwischen dem acoelen Turbellar Convoluta convoluta und Diatomeen der Gattung Licmophora

Newly hatched Convoluta convoluta (Abildgaard) are always without symbionts. They acquire the organisms, which later become their zooxanthellae, with their food. In the field this is an automatic process, since C. convoluta without zooxanthellae have never been reported. The main diet of the young C. convoluta are various diatoms and spores of red algae. The symbionts of C. convoluta originate from diatoms of the genus Licmophora. This fact has been established in young specimens both in the sea and in laboratory cultures. Freshly hatched C. convoluta were fed with Licmophora hyalina (Kütz.) Grunow and Licmophora communis (Heib.) Grunow. Licmophora cells, capable of infesting C. convoluta, slip out of their silica shells and later occur between the cells of the peripherical parenchyma. High population densities of zooxanthellae, produced by numerous divisions of the naked diatom cells, are only possible in the host's parenchyma if the young C. convoluta continue to feed. Adult turbellarians with a high population density of symbionts feed less than the young, but never stop food uptake completely. Artificial infestation with symbionts can be brought about by making sub-adult turbellarians take up isolated zooxanthellae as food. Symbionts outside their host neither propagate nor regenerate silica shells in the culture medium employed. The obligatory nature of the mutual interrelation between C. convoluta and zooxanthellae has been proved by the great difficulties in rearing symbiontless individuals, and by starvation experiments both with sub-adults containing only a few symbionts and adults coloured brownish due to a compact layer of zooxanthellae.     

Effet de l'irradiation gamma (cobalt 60) sur les cultures d'une chlorophycée,Dunaliella bioculata

The influence of gamma radiation on the rate of cell division and the amount of chlorophyll a per cell was studied for Dunaliella bioculata Butcher, 1959 cultures. A decrease in the cell-division rate and an increase of chlorophyll a per cell were observed.     

Investigations of carotenoids in some fauna of the Adriatic Sea. II. Anemonia sulcata and Actinia equina (Coelenterata: Anthozoa)

Investigations have been carried out on the carotenoids in Anemonia sulcata (Pennant) and Actinia equina (L.) (Coelenterata: Anthozoa) from the Adriatic Sea. The presence of the carotenoids was determined by means of columnar and thin-layer chromatography. The following carotenoids were found: Anemonia sulcata: β-carotene, lutein-like (epoxy and free) and astaxanthin; Actinia equina: α-carotene, β-carotene, actinioerythrin, lutein-like (?) and astaxanthin (ester and free).     

Ökologische Kriterien der Technik- und Stoffbewertung: Integration des Vorsorgeprinzips

The development of criteria for the comparative assessment of technologies and substances beyond the toxicological approach and the development of an integrated pattern of criteria is still at the beginning. The criteria presented here for integrating the precautionary principle into the substance and technology assessment have to be further operationlised and completed, in the same way as the criteria which have been discussed and developed within the framework of

- the poisoning and pollutant paradigm

- the equilibrium paradigm

- the sustainability and “Mitwelt” paradigm

- the energy and the general technology assessment debate.

The resolution of the criteria has to be improved and their range (which is certainly limited) has to be explored more precisely. The application of the criteria should never occur mechanically. Technology assessment and substance assessment are not only scientific, but essentially social and, hence, discursive processes. It is not so much the assessment of individual substances which should be in the center of the debate, but rather the comparative assessment of competing techniques, substances and substancerelated development pathways (see vonGleich andRubik, 1966 as a first approach to assess the environmental effects of old and new materials). According to the example of the energy strategies, only the development of competing strategies in the substance field could create the necessary prerequisites for a broad public discourse and thus for a democratisation of the basic substancerelated policy decisions. This discourse is a duty which science and economy have toward society.     

Untersuchungen über die temperaturabhängigkeit des sauerstoffverbrauchs von Crepidula fornicata (Mollusca: Prosobranchia)

The oxygen consumption of the sessile gastropod Crepidula fornicata was measured during autumn 1962 as a function of soft body wet weight (0.04 to 5.2 g) and temperature (2° to 30° C). From the data obtained, the parameters of the allometric formula were derived for describing the relationship between respiration and body size. The parameters were then used for calculating the oxygen consumption of 3 different weight groups (0.1 g, 1.0 g, 10.0 g) at different temperatures. The resulting plot reveals different curves, demonstrating that the influence of temperature on the metabolism of C. fornicata is a function of body size. The ourves relating oxygen consumption to temperature may well be described by a modified Arrhenius-function proposed some years ago (Krüger, 1962). Biological temperature curves may be described by growth functions. Therefore, it is possible to apply the simple Walfordplot for identifying the “normal curves” of Krogh (1914).