Comparison of two carbon analysis methods for monitoring diesel particulate levels in mines

Two carbon analysis methods are currently being applied to the occupational monitoring of diesel particulate matter. Both methods are based on thermal techniques for the determination of organic and elemental carbon. In Germany, method ZH 1/120.44 has been published. This method, or a variation of it, is being used for compliance measurements in several European countries, and a Comité Européen de Normalization Working Group was formed recently to address the establishment of a European measurement standard. In the USA, a 'thermal-optical' method has been published as Method 5040 by the National Institute for Occupational Safety and Health. As with ZH 1/120.44, organic and elemental carbon are determined through temperature and atmosphere control, but different instrumentation and analysis conditions are used. Although the two methods are similar in principle, they gave statistically different results in a previous interlaboratory comparison. Because different instruments and operating conditions are used, between-method differences can be expected in some cases. Reasonable agreement is expected when the sample contains no other (i.e., non-diesel) sources of carbonaceous particulate and the organic fraction is essentially removed below about 500 degrees C. Airborne particulate samples from some mines may meet these criteria. Comparison data on samples from mines are important because the methods are being applied in this workplace for occupational monitoring and epidemiological studies. In this paper, results of a recent comparison on samples collected in a Canadian mine are reported. As seen in a previous comparison, there was good agreement between the total carbon results found by the two methods, with ZH 1/120.44 giving about 6% less carbon than Method 5040. Differences in the organic and elemental carbon results were again seen, but they were much smaller than those obtained in the previous comparison. The relatively small differences in the split between organic and elemental carbon are attributed to the different thermal programs used.     

Ratio and population density of psammolittoral meiofauna as a perturbation indicator of sandy beaches in South Africa

Since 1975, pollution surveys have been carried out along the South African south and west coasts as part of a monitoring program of unpolluted areas and known and anticipated impact areas. To evaluate these data a reference or baseline level was needed. In unpolluted beaches a close relationship between meiofauna and sediment grain size was found and granulometric analysis was found to be important. This relationship was used to evaluated perturbation effects. It was found that contamination by chemical effluent depressed numbers of the nematodes and harpacticoids drastically. Mechanical perturbation increased the number of harpacticoid copepods but did not affect nematode densities. Oil in beaches decreased the number of harpacticoids, while normal nematode densities were found. Organic enrichment increased the number of nematodes, harpacticoid numbers remained normal while the perturbation effect due to sewage increased the number of both taxa.Explanations for these effects are given, together with related chemical analyses. The application of these results to other sandy beaches elsewhere is discussed briefly.     

Eine Fisch-Seeigel-Partnerschaft. Untersuchungen optischer reizparameter beim formenerkennen

The shrimp Tuleariocaris sansibarica and the fish Siphamia permutata live between the spines of the sea urchin Diadema setosum. Visual attration is important in maintaining this association. The spines of the sea urchin act as an optical stimulus for shrimp and fish. The specific optical stimuli which the shrimp (Fricke and Hentschel, 1971) and the fish perceive during their stay with the urchin were investigated and compared. Dummy experiments in the coral reef of the Red Sea (Eilat, Israel) have shown that the fish is able to distinguish between at least 5 different stimuli patterns: color (black or white), diameter, number, distance between spines, and orbital position. Color is less attractive than number and orbital position; the relations between number and orbital position are nearly linear. The different visual systems of shrimp and fish are capable of selecting similar optical parameters. Slight differences in evaluation of single parameters are understood as adaptive processes to an identical environment.     

Fische als Feinde tropischer Seeigel

The techniques used by 9 species of fish (representing 3 families) to capture Diadema sea urchins were observed under water in the Red Sea at Eilat, Israel. Different species displayed different techniques. Fish belonging to the Lethrinidae and Labridae families devoured the entire urchin after capture; Labridae alone were also capable of breaking up large sea urchins by banging them on rocks. The fish did this by shaking its head while holding the urchin in its mouth. Under experimental conditions, fish can distinguish between large and small urchins, and show a preference for the small urchin. The fish also shun contact with some other species of urchins. The trigger fish Balistes fuscus exposed to a dummy sea urchin responds to optical stimuli (body shape and spines); when exposed to a living sea urchin it responds to both optical and behavioural stimuli (movements of the spines). Morphological and ethological preadaptation of the fish to alter its preference for other food is essential before it can develop differentiated capture techniques. The ecological significance of the behaviour of fish in the coral reef ecosystem and the alternating influences in the predator-prey-relationship are discussed.     

Light responses of a scleractinian coral (Plerogyra sinuosa)

During daytime Plerogyra sinuosa Dana displays globular expandable tentacles (bubbles) which foster the photosynthetic ability of the coral. Adaptational responses of this coral to different depths (5–25 m) and light conditions were investigated by photosynthetic pigment analysis, insitu measurements of oxygen production, transplantation and shading experiments. Pigment concentrations per unit tissue dry weight were variable, but unrelated to depth. Pigment concentrations per zooxanthellae cell remained constant and bubble size increased with depth. Light intensity at 25 m was 20 to 25% of the 5-m value, but daily integrated rates of photosynthesis were 65% of the 5-m rates, indicating a higher light utilization efficiency in deeper corals. Coral heads transplanted from 25 to 5 m died within 20 d if not protected against UV-radiation, but corals transplanted from 5 to 25 m acclimatized to the new light condition. Photosynthetic oxygen production and bubble size increased in shaded, sun-adapted corals within 60 min and decreased in sun-exposed, shade-adapted corals. The variable bubble size is interpreted as an adaptational mechanism to optimize light exposure of zooxanthellae.     

Der einfluß des lichtes auf Körperfärbung und dämmerungsverhalten des korallenfisches Chaetodon melanotus

The influence of light on colour patterns and behaviour of the coral-reef fish Chaetodon melanotus were investigated under aquarium and field conditions. Colour pattern and fin position are correlated with agonistic behaviour: they were used as criterion for analysing the behavioural patterns during morning and evening transition.Readiness for attack is correlated with a darkening of the analfin. A specimen with yellow anal fin and spread dorsal fin is more likely to flee. The colour patterns vary during day, twilight, and night time. The speed of colour change was measured experimentally; it appears to be hormonally regulated. During twilight, 5 different colour patterns are related with certain anal-fin colour-patterns and dorsal-fin positions. Swimming activity decreases with reduction in irradiance, while the readiness to flee increases. In groups, specimens become more territorial with diminishing day light. Territorial aggression can be light-dependent; no territorial aggression was observed at illuminations less than 50 lux. Behaviour and concomitant coloration-changes during the evening and morning transition periods are interpreted as adaptational protections against predators. The remarkable white eyespots in the twilight body-coloration could represent a warning signal, and could also have a somatolytic effect. The increased readiness to flee during dusk and dawn may be a behavioural mechanism for reducing predator pressure.     

Tidal-linked behaviour of the shrimp Ligur uvea in a land-enclosed marine pool

At Aldabra Atoll, the shrimp Ligur uvea inhabits a land-locked marine pool which is connected to the sea by a subterranean fissure. The shrimps migrate daily with the tide from a hole in the subterranean labyrinth to a feeding area at the bottom of the pool. The timing of the migration is tidal-linked and independent of light and temperature. With each incoming tide, tagged individuals return to a definite feeding ground. Such homing has not been reported from other L. uvea pools. Feeding activity was quantitatively measured, differences between day and night activity are interpreted as adaptations against predators (terrestrial wading birds). Compared to other L. uvea pools, the shrimps at Aldabra Atoll are exposed to a more rigorous environmental situation, which probably influences the tidal-linked behaviour of the local shrimp population.