Marine production mechanisms: M.J. Dunbar (Editor), Cambridge University Press,Cambridge, 1979. International Biological Programme, 20, 338 pp., illus., £25.00, ISBN 0-521-21937-X

A simple mechanical feeding device is described which can volumetrically deliver a preset quantity of pelleted or granulated dry fish feed.     

Discoid Lupus Erythematosus in Cats

Abstract— The clinical and histopathological features of discoid lupus erythematosus (DLE) are described in four European short-haired cats. Pinnal involvement seems to be highly predictable in feline DLE. In addition an indication exists for the initiating role of exposure to the sun in this disease.
Résumé— Les aspects cliniques et histopathologiques du lupus érythémateux discoide (DLE) sont décrits chez quatre chats européens à poils courts. L'atteinte du pavilion auriculaire semble très fréquente dans le DLE félin. En outre, l'exposition au soleil semble jouer un röle déterminant dans cette entité nosologique.
Zusammenfassung— Die klinischen und histopathologischen Merkmale des diskoiden Lupus erythematosus (DLE) bei vier Europäisch-Kurzhaarkatzen werden beschrieben. Beim felinen DLE scheint die Pinna regelmäßig mitbetroffen zu sein.
Nach dieser Untersuchung besteht Anlaß zur Vermutung, daß die Sonnenexposition bei dieser Krankheit eine auslösende Rolle spielt.     

Tourism and conservation in the Galapagos Islands

The Galapagos Islands are well known for their natural beauty and unique wildlife (60% of all organisms are endemic). As on most oceanic islands the native animals show little or no fear of man. These features make the archipelago very attractive for tourism and since 1970 many people have come to see this ‘last paradise’. Initially the flow of visitors caused few problems. Since 1979, however, the pressure on the fragile ecosystems has increased rapidly and there is great danger that the archipelago will become another ‘lost paradise’.Based on observations made during a two-year stay in the Galapagos Islands, the major threatening developments are discussed. After a brief introduction, the effects on the environment are exemplified and suggestions to deal with the problems are made.The article concludes that unless decisive action is taken soon, Galapagos will become another example of man's dangerous habit of preferring short-term economic gains over long-term ecological and economic interests.     

Feeding activity of the earthworm Eisenia andrei in artificial soil

Quantitative information on the feeding activity of earthworms is scarce but this information is valuable in many eco(toxico)logical studies. In this study, the feeding activity of the compost worm Eisenia andrei is examined in artificial soil (OECD medium), with and without a high-quality food source (cow manure), and at two temperatures (10 and 20 °C). Methods are provided to estimate the most important parameters: gut load, selection of organic matter (OM), digestion efficiency, compaction, gut retention time, and fraction of manure in the diet. Lanthanides (Lu and Tm) were successfully used as inert markers in soil and manure, and we applied Bayesian statistics to analyse the data and fully capture the compounded uncertainty in the parameter estimates. Results show that the compost worm does not feed on soil indiscriminately but is able to select an OM-enriched diet from apparently homogeneous OECD medium. When manure is present on the soil surface, approximately three-quarters of the diet still consists of soil particles. The gut load of the worms was approximately 10% (dwt gut/wwt empty worm), varying little with the treatments. Unfortunately, the digestion efficiency could only be reliably estimated at 20 °C, and was approximately 40%. Temperature clearly affected feeding as a 10° temperature decrease nearly doubled the gut retention time (from 2.9 to 5.5 h), which corresponds to a two-fold decrease in feeding rate. The present data may be used to interpret toxicity and accumulation studies with E. andrei in OECD medium. However, care must be taken, as it seems possible that feeding is influenced by the size of the worm and subtle differences in experimental set-up.     

A comparison of different indices for nitrogen mineralization

Indices of N mineralization in soils of contrasting texture, pH, and organic matter contents were compared at different dates during the growing season. The indices were derived from a 12-week aerobic incubation, determination of the amount of microbial biomass at the start of the incubation, determination of the increase in NH ₄ ⁺ after boiling with 2 M KCl for 2h, and extraction of total soluble N with 0.01 M CaCl₂. Cumulative mineral N increased linearly with time in the course of the incubations. Rates of mineralization in soil samples taken in March 1989 and 1990 were significantly correlated with soluble organic N, while correlations between the mineralization rate and the increase in NH ₄ ⁺ after boiling with 2 M KCl for 2 h were poor for sandy soils and absent for loamy soils. Correlations between NH ₄ ⁺ after boiling with 2 M KCl for 2h and the soil N concentration were highly significant, but no general relationship was found between the mineralization rate and the soil N concentration. Neither biomass N nor biomass C was significantly correlated with the mineralization rate or with one of the chemical indices. Among the methods tested, soluble organic N extracted with 0.01 M CaCl₂ was the only method with any promise for routine measurement of the mineralization capacity of the individual sites.