ALBERT

Description: Calcium carbonate in sediments can greatly effect the engineering properties of those sediments. Factors that may effect engineering properties are: 1) great variation in primary void ratios, (2) inherent strength of carbonate grains, (3) degree of sorting, (4) ratio between grains and matrix, (5) nature and amount of cement, and (6) depth of burial. Deep-sea carbonates appear to be anomalous but do exist in rather large quantities. Their existence must depend upon a combination of physico-chemical and organic-chemical factors that need to be investigated in much more detail.

Description: Mineral resources on and beneath the seafloor are briefly reviewed and the present and future economic value of specific mineral resources is discussed. The results obtained from the cruises of the German research vessel "Valdivia" during its first three years of operation are presented.

Description: The internal shell of the cuttlefish, which acts as a rigid buoyancy tank, is structured to combine high compressive strength — since it must withstand the external hydrostatic pressure — with minimum weighT. The micro-architecture of cuttlebone has been examined by electron microscopy and the relevance of the structure to the mechanical duties required of the shellin vivo are briefly discussed. The inorganic calcareous structure is associated with an organic component which may act as a template for mineralization.

Description: Analyses of bottom trawl samples and feeding experiments in the laboratory revealed a reproduction period ranging from late March to early August in Eledone cirrosa of the Catalonian Sea (Western Mediterranean). The embryonic development, studied for the first time on eggs laid in the laboratory, shows no basic difference from that of other Octopodiae. The newly hatched animals are planctonic; Morphologically, this feature is expressed by a relatively small arm-length.

Description: Five species of Sepiola were reared in the laboratory from egg to adult size. Spawning was achieved in 3 species of Sepiola afteer 5 to 7 months. The growth rate of the species reared did not depend upon temperature, which ranged from 12,5° to 20°C. A fairly constant size increase (2,5mm mantle length/month) was observed in Sepiola during the 5 months after hatching. In Sepietta, the same growth rate was observed until the fourth month after hatching, when it increased to the rate of 5 mm mantle length/month.

Description: A new equation for the speed of sound in sea water has been developed with validity not only for realistic combinations of the parameters salinity, temperature, and pressure, but with extension to pure water as well. This new equation, referred to as NRL II, has a standard deviation of 0.05 m/sec. Tables are presented comparing calculations using this new model to each of eight earlier equations. Graphs are also included indicating approximate corrections that could be applied to existing sound speed profiles, but it is recommended that such profiles be recalculated and new ones obtained according to NRL II.

Description: Statoliths of the short-finned squid Illex illecebrosus were chemically analyzed to define their chemical composition and surveyed by scanning electron microscope to differentiate internal structural patterns. X-ray diffraction data demonstrated that L Illecebrosus statoliths were composed principally of CaCQ in the aragonite crystal form. The crystals occurred in a protein matrix to form incremental patterns which radiated from the nucleus to the edge of the statoliths. The protein matrix comprised approximately 5% of the statolith by weight. The protein was principally composed of acidic amino acids. A high abundance of aspartic acid in the protein matrix indicated that the matrix would function as a template in the initiation and acceleration of the crystal growth of CaCO. The rhythmic microstructural patterns, constructed of aragonite crystals in the protein matrix, wer e suggested to be daily in formation and subsequent growth estimations were in agreement with known life history information. The stable isotopic composition of the carbonate of L illecebrosus statoliths suggested that oxygen may be deposited in isotopic equilibrium with the surrounding environment while carbon appeared to be related to biological processes. The information recorded in the statotiths as incremental growth and stable isotopic composition could provide valuable insights into the ecological history of squid.

Description: A technique for rearing the loliginid squids Sepioteuthis sepioidea and Doryteuthis plei is reported. Specimens of the former were reared from eggs to sexually mature adults, and maintained for a maximum of 146 days; adult D. plei were maintained for 38 days. Choice and quantity of food was most important for the survival of all sizes, particularly young squid. Newly hatched specimens thrived on Mysidium columbiae. Both species fed at a rate of 30 to 60% of their body weight daily; starvation occurred when intake fell below 10 to 15%. Food conversion efficiency averaged between 10 to 20%. Growth was rapid and steady. S. sepioidea grew to a maximum of 105 mm and 77 g in less than 5 months; D. plei grew an estimated 20 mm/month. Experimental data indicate a lethal minimum salinity for both species at about 27‰. Lethal minimum and maximum temperatures for young S. sepioidea are 17.5° to 18.0°C, and 32.5° to 33.0°C, respectively. Young consume 0.64μl O2/mg wet weight/h. Opaque tanks, with a semi-natural bottom substrate and special ultra-violet (UV) illumination, are advantageous for rearing and maintenance.

Description: The response of the benthos to the break up of anoxia in the Kiel Bight (Western Baltic Sea), and to three succeeding events of “external” food supply, consisting of a settled autumn plankton bloom, resuspended matter and macrophyte input during winter, and of a sedimented spring phytoplankton bloom, is described on a community level. The first input of oxygen broke up anoxic conditions and made stored food resources available to decomposition. This “internal” food supply, mainly consisting of protein (folin positive matter), was followed by a drastic increase in heat production and ATP-biomass and caused a period of low redox potential, which lasted for several weeks. During this phase, a plankton bloom (dinoflagellates and diatoms) settled to the sea floor. Although there was an immediate response of benthic activity, this food input was not completely consumed by the strongly disturbed benthic community. During winter resuspended matter and the input of macrophyte debris caused another maximum in benthic activity and biomass despite the low temperature. The response to sedimentation of cells from a diatom bloom during mid March was also without any time lag and was consumed within 5–6 wk. A comparison of the amount of particles collected in a sediment trap with the increase of organic matter in the sediment demonstrated that the sediment collected four times (autumn) and seven to eight times (spring) more than measured by the sediment trap. Strong indications of food limitation of benthic activity were found. During autumn and winter these indications were caused more by physical than by biological processes. The three events of “external” food supply caused a temporary shift in the type of metabolism towards fermentation processes and reduced the redox potential. In spring the development of the benthic community was still being strongly influenced by the events of the preceding summer and autumn.