ALBERT

Description: Modern competition research started with G.E. Hutchinson’s, Homage to Santa Rosalia, and his now-famous question “why are there so many species?” (Hutchinson 1959,1961). This confronted observed species richness with the competitive exclusion principle, a principle that had been derived from theory and from highly artificial experiments. It would always have been easy to point at the “artificial” character of the competitive exclusion principle. Indeed many researchers have refused to deal with Hutchinson’s question because they considered it a pseudo-problem, which arose from a contradiction between overly simplified theory and complicated reality. However, those who took Hutchinson’s challenge seriously have gained fundamental insights into how competition plays out in nature, how species coexist, and how communities function. In this final chapter we attempt to synthesize these insights as they have been presented in this book. We focus on six key topics: - Identification of major trade-off axes (Sect. 8.1) - Confirmation of the “intermediate disturbance hypothesis”, and detection of interactions among competition, resource supply, predation and disturbance in field experiments (Sect. 8.2) - The interplay of space colonization, dispersal and neighborhood competition in sessile communities (Sect. 8.3) - Potential for chaotic, self-generated heterogeneity in communities (Sect. 8.4) - Role of exclusive resources in competition among mobile animals (Sect. 8.5) - Coexistence by slow exclusion (Sect. 8.6)

Description: One concept of evolutionary ecology holds that a living fossil is the result of past evolutionary events, and is adapted to recent selective forces only if they are similar to the selective forces in the past. We describe the present environment of the living coelacanth Latimeria chalumnae Smith, 1939 at Grande Comore, western Indian Ocean and report depth-dependent cave distribution, temperature, salinity and oxygen values which are compared to the fish's distribution and its physiological demands. We studied the activity pattern, feeding behaviour, prey abundance and hunting success to evaluate possible links between environmental conditions, feeding ecology and evolutionary success of this ancient fish. Transmitter tracking experiments indicate nocturnal activity of the piscivorous predator which hunts between approximately 200 m below the surface to 500 m depth. Fish and prey density were measured between 200 and 400 m, both increase with depth. Feeding tracks and feeding strikes of the coelacanth at various depths were simulated with the help of video and laser techniques. Along a 9447 m video transect a total of 31 potential feeding strikes occurred. Assuming 100% hunting success, medium-sized individuals would obtain 122 g and large females 299 g of prey. Estimates of metabolic rates revealed for females 3.7 ml O2 kg−1 h−1 and for males 4.5 ml O2 kg−1 h−1. Today coelacanths are considered to be a specialist deep-water form and to inhabit, with their ancient morphology, a contemporary environment where they compete with advanced, modern fish.

Description: Sediment transport processes in the northern North Atlantic have been investigated on the basis of various numerical models. A general circulation model has been used to investigate large-scale particle transport, a reduced gravity plume model has been used to investigate particle transport by cascading from the shelves into the deep basins, an ocean slice model has been used to investigate particle exchange processes between a bottom current and the ambient water mass, and a Bottom Boundary Layer model has been used to investigate particle interactions influencing the settling behavior of suspended particles. In this paper, the various processes investigated in these models are described (i) schematically, (ii) on the basis of field data, if available, and (iii) by employing results from numerical simulations. In a first attempt the northern North Atlantic will be divided into separate process defined areas, which can be used in carbon budgeting, for example.

Description: Am Süd-Ausgang des Roten Meeres entstehen unter idealen Wachstumsbedingungen fast reine Korallen-Saumriffe, die als dünne Platten oft kilometerweit mit einer Geschwindigkeit von Zentimetern pro Jahr auf ihrem Schutt von der Küste horizontal gegen das Meer vorwachsen. Aufgetauchte Saumrifte, ein flacher Bootskanal oder abradierte Riffoberflächen weisen auf pleistozäne und jüngere Meeresspiegelschwankungen bzw. tektonische Verstellungen hin. Von einer gewissen Breite an bilden sich auf den Riffen Inseln in Form langgestreckter Rücken aus Korallensand, hinter denen sich stellenweise Mangrove ansiedelt oder Salze in flachen Lagunen abscheiden. Schließlich kann der Strand auf das Saumriff vorverlegt und dieses in die Küstenebene einbezogen werden.

Description: Acoustic telemetry was used to examine patterns of activity and space utilisation of coelacanths, nocturnal predators which spend the day in submarine caves. Nine coelacanths (Latimeria chalumnae) were tracked, each for a period of 1 to 16 nights at Grande Comore, West Indian Ocean. Activities lasted on average 9 h, usually starting shortly after sunset and ending before sunrise. Vertically, coelacanths moved up and down at and below cave level by following the bottom contour, mainly between 180 and 400 m depth. The deepest record was 698 m, the shallowest 133 m. Most time was spent between 200 and 300 m depth. Large individuals performed deep excursions to depths below 400 m, usually once per night. The fish spent most time in water temperatures of 15 to 19 °C; they rarely ventured into waters warmer than 22 °C measured at depths shallower than 160 m depth. Horizontally, coelacanths stayed in narrow areas ranging from 〈1 to 10 km of coastline. Coelacanths are extremely slow drift-hunters with an estimated average swimming speed of 3.2 m min−1, often travelling not more than 3 km per night. They probably take advantage of local upwelling and downwelling and slow currents occurring parallel to the steep slopes. This study shows that coelacanths are inhabitants of the subphotic zone, where they are active mainly below the depth of their daytime refuges.

Description: Carbonate precipitates on mounds and along tectonic scarps off the Costa Rica margin are manifestations of subduction-induced dewatering. The long-term dewatering history is recorded in mineralogical, petrological and isotope signals of carbonates recovered from these sites. The carbonates are strongly depleted in δ13C (−11 to −53‰ PDB) and enriched in δ18O (+4 to +8‰ PDB). Thermogenic methane and biogenic methane were identified as sources of the carbon. Chemoherm carbonates and seepage-associated carbonates formed in a focused flow regime have lighter δ13C values, while others formed in a more diffusive flow regime have slightly enriched C isotope values. Three fluid components were inferred based on the calculation of equilibrium δ18O: clay dehydration water, gas hydrate water and seawater. Calculated equilibrium δ18O values of carbonates from different down-core depths as well as from different precipitation stages show that the δ18O of the precipitating fluid is progressively depleted with time. Dolostones showing a methane-C source and a well constrained O-isotope signature are thought to have formed at depth in the sediment and subsequently became exhumed. Glauconitic sandstones cemented by methane-derived carbonate provide evidence that fluid and solid material have been expelled by the mud volcano.

Description: A detailed analysis of beak length to body size and mass measurements was carried out for the glacial squid Psychroteuthis glacialis, which is an endemic cephalopod species in the Southern Ocean. Beak lengths (lower rostral length) were measured from 211 specimens which had been sampled in the Atlantic sector of the Southern Ocean. The basic idea was to find some calibration model in order to inter- or extrapolate missing mantle length and/or wet body mass data by means of beak lengths. The relationships between beak length and mantle length/wet body mass bear essential information for future use in biomass estimates in Southern Ocean top predators, since beaks of P. glacialis occur frequently in the stomach contents of Antarctic seabirds, seals and toothed whales. Therefore, lower rostral lengths were plotted against both mantle length and wet body mass to determine the relationship between these variables. The relationships had limited scatter and very high coefficients of determination, showing that lower rostral length is a good predictor of the squid's mantle length and wet mass. A non-linear 3rd order polynomial regression of lower rostral length against mantle length was identified as the best fitted calibration model, explaining 93% (R 2) of the associated variance. The relationship between lower rostral length and wet body mass was empirically well fitted through regressing ln-transformed values of lower rostral length against wet body mass, explaining 95% (R 2) of the associated variance. The present investigation provides measurements for a wide size range of P. glacialis individuals compared to earlier studies, which were limited on very small data sets.

Description: Objective: Hypersensitivity pneumonitis due to dry sausage mould has been reported in workers who brush off the excess mould which coats dry sausage. Prevalence of symptoms and sensitization to mould among these pork-butchery workers is unknown. The aim of the study was to assess the clinical, radiographic, functional, and immunological features in exposed and non-exposed workers in semi-industrial pork butcheries. Patients and methods: Symptoms, and serum precipitins against mould extracts, were studied in workers in semi-industrial pork butcheries. Of 600 workers asked to participate, 123 (20.5%) were included. Fifty-nine workers, exposed to dry (raw) sausage mould and Penicillium nalgiovense were compared with 64 non-exposed subjects, for symptoms, chest X-rays, spirometry and CO-transfer measurements. Precipitating antibodies were detected by immunoelectrophoresis and electrosyneresis. Results: Sneezing, cough, dyspnoea, nasal obstruction, headache, and discomfort were significantly more frequent in the exposed group at work and after work than in the control group (P 〈 0.05). The prevalence of precipitating antibodies for sausage mould was higher in the exposed group (37%) than in the non-exposed group (9%) (P 〈 0.01). The mean number of precipitating lines measured by electrosyneresis was higher in exposed workers than in non-exposed workers for mould extract (1.09 vs 0.28, P 〈 0.05) and for Penicillium nalgiovense (1.77 vs 0.33, P 〈 0.05). No specific X-ray opacity or lung function impairment was found in either group. Conclusions: Clinical symptoms and sensitization to Penicillium nalgiovense are frequent among workers exposed to mould during brushing in dry sausage plants.

Description: The chemical composition (alkalinity, pH, NH4+, PO43-, Si, H2S, Cl-, Ca2+,and SO42-) of interstitial water was studied in the sediments of the Sea of Okhotsk at sites of methane emission. Variations in alkalinity were observed in the sediments from a typical seawater value (2.3 mM/kg) to 63 mM/kg. It is demonstrated that they are caused by the processes of sulfate reduction and methane generation. Based on the balance relationships, an equationwas constructed connecting changes in alkalinity with variations of Ca2+, SO42- and NH4+ in interstitial solutions.