ALBERT

Description: Dates of Cruise: 18.7.96 - 4.8.96. General Subject of Research: Sampling of active volcanism on the middle Kolbeinsey Ridge and the Eggvin Bank. Port Calls: Kiel, Reykjavik.

Description: Marine organic-carbon-rich deposits occur where there is an ample rain of organic particulate material to the sea floor and conditions favorable to its preservation. It was originally thought that the accumulation of organic carbon (Corg) was dependent mostly on anoxic conditions at the site of deposition; two such environments, the stagnant basin and the O2 minimum, were often cited as models. High productivity in the overlying waters has become recognized to be of greater importance. In an overall evaluation of burial of Corg in marine sediments, it is apparent that terrigenous input of organic matter is the largest source, followed by marine organic matter fixed in highly productive coastal areas receiving nutrients from land. In terms of rich accumulations of marine organic matter most likely to generate petroleum, areas of ocean upwelling along continental margins are most significant.

Description: It is well documented that animals take risk of predation into account when making decisions about how to behave in particular situations, often trading-off risk against opportunities for mating or acquiring energy. Such an ability implies that animals have reliable information about the risk of predation at a given place and time. Chemosensory cues are an important source of such information. They reliably reveal the presence of predators (or their presence in the immediate past) and may also provide information on predator activity level and diet. In certain circumstances (e.g., in the dark, for animals in hiding) they may be the only cues available. Although a vast literature exists on the responses of prey to predator chemosensory cues (or odours), these studies are widely scattered, from marine biology to biological control, and not well known or appreciated by behavioural ecologists. In this paper, we provide an exhaustive review of this literature, primarily in tabular form. We highlight some of the more representative examples in the text, and discuss some ecological and evolutionary aspects of the use of chemosensory information for prey decision making. Curiously, only one example illustrates the ability of birds to detect predator odours and we have found no examples for terrestrial insects, suggesting a fruitful area for future study.

Description: The role of cephalopod haemocyanins in oxygen transport is analysed in the light of the coordination of metabolism, acid‐base regulation and gas exchange processes. Results obtained in squid, the most active among cephalopod species, indicate that the pH dependence of their haemocyanin supports a Po2‐buffer function for the pigment. The release of base equivalents from the tissue during aerobic exercise and the minimal release of protons during anaerobic octopine formation protect arterial pH and, thus, oxygen binding. The extent of respiratory acidification and haemocyanin deoxygenation on the venous side is higher in blood returning from the mantle than from the head. In vivo blood gas measurements reported for squid and for other cephalopod species support the conclusion that CO2 accumulation and respiratory acidification of the blood occur in excess of the effect expected from the consumption of haemocyanin bound O2 and RQ values derived from protein catabolism. This suggests that a considerable fraction of the oxygen consumed by the animal enters via the skin, especially in the mantle. Model calculations demonstrate that skin O2 uptake in the mantle increases during activity in squid. In other cephalopod species like cuttlefish, the special process of arterial CO2 binding to oxygenated haemocyanin and its release during venous deoxygenation may provide the excess CO2 required for venous acidification. All of these processes allow the classical Bohr effect to function supporting oxygen loading at the gills and oxygen unloading in the tissues. The large pH‐dependent cooperativity and the Bohr effect combine to maximize the Po2‐buffer function of the respiratory pigment. These adaptations probably evolved after the ancestors of modern cephalopods lost their shells and locomotor activity assumed a greater role in their lifestyle.

Description: A number of reproductive indices were compared with a subjective maturity scale for assessment of Loligo forbesi maturity. The ratio between nidamental gland length and mantle length corresponded well with female maturation, as did the ovary mass-soma mass and nidamental gland mass-soma mass ratios. For males, the ratio between spermatophoric complex mass and somatic mass was found to be the most suitable for maturity assessment. The timing of recruitment and maturation of L. forbesi in Irish waters was described from the size and maturity of squid in commercial landings in the south of Ireland during the years 1991–1993. Immature squid first appeared in commercial catches in July and August, and this represented the main period of recruitment. A second period of recruitment was apparent in December 1991, but was not identified in the 1992–1993 season. Mature females were present in the commercially exploited population between November and April, with a small number also found in the summer. The abundance of egg masses was used to indicate timing of spawning. Egg masses recovered from the Cork coast indicated that peak spawning occurred during the winter months, but continued on a small scale for much of the year.

Description: Some deep water squids are known to achieve neutral buoyancy by storing ammonium in their body tissues. The Cranchiidae use a unique coelomic cavity to store ammoniacal fluid; in 15 other families, ammonium appears to be sequestered in either vacuoles in the active body tissues or in a gelatinous outer layer. The hypothesis that these squids form a single lineage is here reconsidered through reviews of morphological characters that could support this hypothesis and physiological mechanisms that could contribute to the repeated evolution of ammonium storage. No readily apparent character identifies all ammoniacal squids as belonging to a single lineage, although 5 families of tissue ammoniacal squids appear to be monophyletic. If the elaborate funnel locking apparatus of this group arose within the clade, it is not homologous with that in other taxa, refuting a basis on which close relationships were suggested for ammoniacal squids. Given the limited data available, we question whether some squids considered to be ammoniacal may develop these characters as a result of senescence. Squids are all thought to derive energy from amino acid catabolism, produce large quantities of ammonia and have very low blood pH's which effectively remove ammonia from cells that produce it. They also minimize H+ ion transfer between muscle cells and blood. These features may be important preadaptations for ammonium storage. Given the physiological data, and the absence of morphological evidence supporting monophyly, we argue that ammoniacal squids be best considered to be a polyphyletic group, evolved in parallel.