ALBERT

Description: Silica chimneys were discovered in 1985 at 86°W in the rift valley of the Galapagos Spreading Center at 2600 m depth (“Cauliflower Garden”). The inactive chimneys lack any sulfides and consist almost entirely of amorphous silica (up to 96 wt.% SiO2, opal-A); Fe and Mn oxides are minor constituents. Oxygen isotope data show that formation of the silica chimneys took place at temperatures between 32°C (+29.9‰ δ18O) and 42°C (+27.8‰ δ18O).Th/Udating reveals a maximum age of 1440 ± 300y. Amorphous silica solubility relations indicate that the silica chimneys were formed by conductive cooling of pure hydrothermal fluids or by conductive cooling of a fluid/seawater mixture. Assuming equilibrium with quartz at 500 bars, initial fluid temperatures of more than 175°C (i.e., a concentration of 〉 182 ppm SiO2) were required to achieve sufficient supersaturation for the deposition of amorphous silica at 40°C and 260 bars. If the silica chimneys originate from the same or a similar fluid as higher-temperature ( 〈 300°C) sulfide-silica precipitates found nearby (i.e., 2.5 km away), then subsurface deposition of sulfides may have occurred.

Description: It has long been recognized that the transition from the last glacial to the present interglacial was punctuated by a brief and intense return to cold conditions. This extraordinary event, referred to by European palynologists as the Younger Dryas, was centered in the northern Atlantic basin. Evidence is accumulating that it may have been initiated and terminated by changes in the mode of operation of the northern Atlantic Ocean. Further, it appears that these mode changes may have been triggered by diversions of glacial meltwater between the Mississippi River and the St. Lawrence River drainage systems. We report here Accelerator Mass Spectrometry (AMS) radiocarbon results on two strategically located deep-sea cores. One provides a chronology for surface water temperatures in the northern Atlantic and the other for the meltwater discharge from the Mississippi River. Our objective in obtaining these results was to strengthen our ability to correlate the air temperature history for the northern Atlantic basin with the meltwater history for the Laurentian ice sheet.

Description: Radiocarbon ages for benthic and planktonic foraminifera from the late glacial sections of two Atlantic and two Pacific cores are reported. The differences for benthic-planktonic pairs suggest that the radiocarbon age for deep Atlantic water was somewhat larger than today's (i.e., 600±250, as opposed to 400 years) and that the radiocarbon age for deep Pacific water was also slightly larger than today's (2100±400, as opposed to 1600, years). Our results suggest that during glacial time, the deep Pacific was, as it is today, significantly depleted in radiocarbon relative to the deep Atlantic. As many questions remain unanswered regarding the reliability of this approach, these conclusions must be considered to be preliminary.

Description: Chemical composition of Zostera marina L. seed and shoots was determined. Morphology and histochemistry of mature seeds were studied by fluorescence, brightfield and scanning electron microscopy to locate storage constituents in the seed. Starch content in the mature seed was 51% and was the major storage reserve in the embryo and a minor component in the testa. Starch in the shoots ranged from 0.3 to 2.3%. Protein, located in the embryo as small protein bodies, comprised about 9.0% of the seed. Protein in shoots ranged from 6–15%. Protein quality of both seeds and shoots resembled corn in composition, and the first limiting amino acid was lysine. Shoots were high in minerals, fiber and ash, while seeds were lower in these constituents. Fat was low (0.3–1.7%) in both shoots and seeds.

Description: A marine geophysical survey that used Seabeam, multi- and single-channel seismic reflection, gravity, and magnetic profiling was conducted in two locations along the landward slope of the Peru Trench. This survey was conducted during the SeaPERC cruise of the Jean Charcot in July 1986 (Bourgois et al., 1986a; Bourgois et al., 1986b; Bourgois et al., 1987; Bourgois et al., in press). These areas were two possible drilling locations for ODP Leg 112, which was scheduled to begin in November 1986. The drilling transects center around latitudes of 5°30'S and 9°30'S, along multichannel seismic lines CDP-3 and CDP-2, respectively. The northern transect is located in the Paita Zone (Fig. 1, Box 2), and the southern transect is in the Chimbote Zone (Fig. 1, Box 6). During Leg 112, we drilled two sites (683 and 685) in the Chimbote area. This became the northern transect of Leg 112. Here, we report the Seabeam data acquired during the SeaPERC cruise. Drilling results from Sites 683 and 685, the CDP-2 multichannel seismic record, and the Seabeam data provide a threedimensional view of this region.

Description: Current knowledge on biology of the squid family Gonatidae in the subarctic Pacific is reviewed. Up to this date, 10 species of the genus Gonatus (of which two are unnamed yet), a single species of the genus Eogonatus, six species of the genus Gonatopsis and two species of the genus Berryteuthis are known from the subarctic Pacific. Their distribution patterns can be classified into three major types: (1) trans-Pacific species (with two subtypes), (2) Northwest Pacific species, and (3) Northeast Pacific species. The family Gonatidae is divisible into two broad ecological types: (1) muscular, epi- to mesopelagic and eurybathic forms, and (2) lessmuscular, stenobathic and nektobenthic forms. Little is known about the prey of gonatids. However, their predators are diverse, including fishes, sea-birds and mammals, thus gonatids play an important role for the food-chain in the subarctic Pacific. Structures of the tentacular club, particularly metamorphose into hooks are important characters for tracing morphological changes in growth. Allametrie growth of some species has been clarified. The spawning biology of two commercially fished species (Gonatopsis boreaUs and Berryteuthis magister) is described, but spawning adults of non-commercial species have seldom been observed. The seasonal occurrence of planktonic juveniles of gonatids may be related to spring phytoplankton blooms.

Description: An empirical equation relating O2 consumption (power input) to pressure production during jet-propelled swimming in the squid (Illex illecebrosus) is compared with hydrodynamic estimates of the pressure-flow power output also calculated from pressure data. Resulting estimates of efficiency and stress indicate that the circularly arranged obliquely striated muscles in squid mantle produce maximum tensions about half those of vertebrate cross-striated muscle, that "anaerobic" fibers contribute to aerobic swimming, and that peak pressure production requires an instantaneous power output higher than is thought possible for muscle. Radial muscles probably contribute additional energy via elastic storage in circular collagen fibers. Although higher rates of aerobic power consumption are only found in terrestrial animals at much higher temperatures, the constraint on squid performance is circulation, not ventilation. Anaerobic power consumption is also among the highest ever measured, but the division of labor between "aerobic" and "anaerobic" fibers suggests a system designed to optimize the limited capacity of the circulation.

Description: Abrupt changes in climatic conditions have been seen at high latitudes in the North Atlantic and the Antarctic at 13 kyr BP. It is important to determine whether this abrupt change was confined to high-latitude regions or whether it was global. Here we present results demonstrating an abrupt change in the rate and character of sedimentation in the South China Sea at the close of the last glacial period. Radiocarbon dating and its position in the oxygen isotope shift suggest that this change may be coincident with the changes found at high latitudes.

Description: Abrupt changes in climatic conditions have been seen at high latitudes in the North Atlantic1 and the Antarctic2,3 at 13 kyr BP. It is important to determine whether this abrupt change was confined to high-latitude regions or whether it was global. Here we present results demonstrating an abrupt change in the rate and character of sedimentation in the South China Sea at the close of the last glacial period. Radiocarbon dating and its position in the oxygen isotope shift suggest that this change may be coincident with the changes found at high latitudes.

Description: In the animal kingdom evolutionary size changes involved increasing, decreasing and stationary patterns. Planktic and benthic Foraminifera chiefly increased their size during evolution. This increase, however, did not always occur gradually, but could be interrupted by periods when the animals maintained or even decreased in size. The rate of the size increase is different for the various species examined, some benthic forms grew only 10% during the Oligocene-Pleistocene interval, while for others this figure was up to 96%. Some benthic species increased in size in certain areas, but not in others. It is not improbable that some phylogenetic trends of planktic Foraminifera representing, according to stratigraphers, the evolution of one species into another, represent in reality, from the biological point of view, specimens of the same species which changed their size and in addition some minor morphological traits which are encompassed by the normal span of intraspecific variability. A comprehensive understanding and explanation of the size change of Foraminifera needs much additional research.

Description: The release of exchangeable Mg in marine sediments from displacement by ammonium ions was estimated by way of experimentally determining the parameters that govern this ion-exchange equilibrium on solid geochemical phases: smectite, humic acid, illite and opal. We showed that: (a) both the conditional selectivity constant as well as the solid concentration are important parameters in determining the relative contribution of ammonium-exchangeable Mg from smectite, organic matter, illite and opal; and (b) that, except in the cases where opal or organic matter concentrations are very high, the clays are the dominant carrier phases for labile Mg which is exchangeable by ammonium. A model, based on the sum of the contributions from the major geochemical phases present in the sediment reliably predicts the amount of Mg released by exchange with ammonium in marine sediments.

Description: A radiotracer technique, employing 27Mg, is used to determine the Mg released by ammonium exchange on undis-solved humic acid in a seawater medium. This new method allows for the measurement of exchangeable Mg on the solid phase surface, which eliminates the problem caused by the high-Mg background in the seawater matrix. The precision calculated from the counting statistics is better than ±2%; the reproducibility among repeated counts ranged from ±1% to ±3%. The higher sensitivity of the method allows for monitoring the MgNH4 exchange at concentrations as low as 30 mM NH4. This is a major improvement relative to the data obtained with the analytical methods used so far, which allow detection of exchangeable Mg only at NH4 concentrations higher than 1 M. The lower experimental concentrations are more in accordance with the natural ammonium levels found in anoxic marine sediments. For the undissolved humic acid used in this experiment, the amount of exchangeable Mg in apparent equilibrium with an ammonium-free seawater matrix was found to be 96.6 ± 0.4 meq/100g. The Mg-NH4 exchange on humic acid in seawater comes to a steady-state value in 〈 18 min. The conditional equilibrium constant obtained for this reaction, Kcond = 0.039 ± 0.001 M−1. The technique can be expanded to other geochemical solid phases in seawater and it can be modified to study the behavior of the major cations by using 24Na, 42K and 49Ca.

Description: The late Pliocene phase of large-scale climatic deterioration about 3.2-2.4 Ma BP is well documented in a number of (benthic) 〈latex〉$\delta^{18}$〈/latex〉O records. To test the global implications of this event, we have mapped the distribution patterns of various sediment variables in the Pacific and Atlantic Oceans during two time slices, 3.4-3.18 and 2.43-2.33 Ma BP. The changes of bulk sedimentation and bulk sediment accumulation rates are largely explained by the variations of CaCO〈latex〉$_3$〈/latex〉-accumulation rates (and the accumulation rates of the complementary siliciclastic sediment fraction near continents in higher latitudes). During the late Pliocene, the CaCO〈latex〉$_3$〈/latex〉-accumulation rate increased along the equatorial Pacific and Atlantic and in the northeastern Atlantic, but decreased elsewhere. The accumulation rate of organic carbon (C〈latex〉$_{org}$〈/latex〉) and net palaeoproductivity also increased below the high-productivity belts along the equator and the eastern continental margins. From these patterns we may conclude that (trade-) wind-induced upwelling zones and upwelling productivity were much enhanced during that time. This change led to an increased transfer of CO〈latex〉$_2$〈/latex〉 from the surface ocean to the ocean deep water and to a reduction of evaporation, which resulted in an aridification of the Saharan desert belt as depicted in the dust sediments off northwest Africa.

Description: We examined multichannel seismic records CDP-1, CDP-2, CDP-3, 1017, and records obtained during the site survey for Leg 112 to evaluate stratigraphy, tectonic evolution, and the structural character of the active margin offshore of Peru. From the reprocessed records we learned that the regionally uniform structure of the margin between 4°S and 14°S is modified by local tectonism. Common elements are crust of continental affinity beneath the middle and upper slope and an accretionary complex below the lower slope. The forearc basins have a varied tectonic history, which led to considerable differences in subsidence history and deformational style. Compressional tectonics dominate the front of the margin, whereas extension accounts for deformation landward of the midslope area.

Description: Perhaps the most significant event in the Cretaceous record of the carbon isotope composition of carbonate1,2, other than the 1–2.5 ‰ negative shift in the carbon isotope composition of calcareous plankton at the Cretaceous/Tertiary boundary3, is the rapid global positive excursion of ~2 ‰ (13C enrichment) which took place between ~91.5 Myr and 90.3 Myr (late Cenomanian to earliest Turonian (C/T boundary event))1,4,5. This excursion has been attributed to a change in the isotope composition of the marine total dissolved carbon (TDC) reservoir resulting from an increase in rate of burial of 13C-depleted organic carbon, which coincided with a major global rise in sea level5 during the so-called C/T oceanic anoxic event (OAE)6. Here we present new data, from nine localities, which demonstrate that a positive excursion in the carbon isotope composition of organic carbon at or near the C/T boundary7,8 is nearly synchronous with that for carbonate and is widespread throughout the Tethys and Atlantic basins (Fig. 1), as well as in more high-latitude epicontinental seas. The postulated increase in the rate of burial of organic carbon may have had a significant effect on CO2 and O2 concentrations in the oceans and atmosphere, and consequent effects on global climate and sedimentary facies.

Description: The diet of Ommastrephes bartramii (Lesueur, 1821) was determined by analysing the stomach contents of 73 squid caught in the South-West Atlantic Ocean. There were three main prey groups, Cephalopoda (in 82% of the squid stomachs), Osteichthyes (34%) and Crustacea (18%). Cannibalism was common. Squid of the families Histioteuthidae and Enoploteuthidae and other teuthoids were less frequent in the diet. The fish prey was predominantly Myctophidae, of various species. The bulk of the prey was mesopelagic species that migrate into the epipelagic layers at night.

Description: In order to elucidate the stock structure and growth of neon flying squid, seasonal variations in dorsal mantle length, sex ratio, gonad weight and degree of sexual maturity of this species are presented here on the basis of the results of biological measurements of the samples taken by squid gillnetters during June and December in 1983-1985. The majority of the sampled squid were immature and not copulated females, while the proportion of males in number was only 2.4% in the 3-year average, and about half of the males were semi-mature (11%) or mature (36%). The principal modal mantle length in females shifted from 37cm level in June to 45cm level in September, then backed again to a smaller modal size within the range of 35-41cm in October-November. The ovary weights showed a general tendency to gradually increase between June and August, but this was followed by an abrupt decrease in September. Judging from these results, it is presumed that Japanese squid squid gillnetters mainly catch “extra-large sized” group of neon flying squid in June-September and “large sized” one in October-December, selectively out of four different size groups in the northern North Pacific.

Description: A new species of Eledone is described from the southwestern Atlanlic at deptlis of 60 to 160m, off Rio Grande do Sul, Brazil. The characters that dislinguish this species trom the other species of the genus are presented, as well as a morphometric comparison with the sympatic Eledone massyae Voss, 1964.

Description: 1. Two Brazilian species of Eledone were examined by isoenzyme electrophoresis and isoelectric focusing. 2. The analysis of 24 alleles distributed among 14 enzyme loci exhibited a genetic index identity of 0.73. 3. The loci Xdh, Est, Adh-l, Gpdh-2, Mdh-1, Mdh-2, Sod-I and Sod-2 are fixed at different isoenzyme for each population. 4. The genetic result and the isoelectric focusing pattern shows that the two taxa are reproductivity isolated and, overall, the evidences indicate that they are separate species.

Description: Eleven monthly samples of the myopsid squid Alloteuthis subulata were collected from the English Channel with a small otter trawl in 1985-86. Squid were sexed and assigned a maturity stage. Measurements were made of mantle length and dry weight of gonad and somatic tissue. Maximum length of life for squid from this population is ca 1 yr. Immature squid are recruited into the population twice during the year, in spring and summer. Males and females start to mature at 30 to 40 mm mantle length. The demography of the population is complex, and more difficult to interpret for males. There were apparently 3 spawning groups of females in the year sampled. The length exponent for body weight is very low in both males and females. Males mature earlier than females and male gonad weight is poorly correlated with body weight in squid 〉 90 mm mantle length. Gonad weight increases logarithmically in relation to total body weight in females but gonad production is not appreciable until mantle length exceeds 100 mm. The gonad accounts for ca 25 O/O of the body mass of females at the maximum mantle length of 140 mm. This suggests that A. subulata, In common with some other cephalopods, has a low reproductive effort by comparison with the lifetime reproductive effort of species of benthic iteroparous mollusc.

Description: The central problem of paleoceanography is the history of the circulation of the ocean. Although speculation about ancient oceanic circulation goes back to the past century, the field of paleoceanography was founded in the 1950s as oxygen-isotope studies suggested that oceanic deep waters were warmer in the past than they are today. Extensive coring of deep-sea sediments by numerous expeditions after World War II was followed by the ocean drilling programs, providing a rich data base. Paleoceanographic interpretations have tried to explain the most obvious changes in sea-floor sediments and their contained fossils: changing paleotemperatures indicated by oxygen isotopes, fluctuations in the calcium carbonate compensation depth, accumulations of organic carbon-rich sediments, and the unexpected abundance of hiatuses in a setting which had been thought to be the ultimate sedimentary sink. The result has been the intriguing discovery that although the positions and circulation of the major surface gyres is generally stable, the deep circulation of the ocean may reverse on a variety of time scales. It has been suggested that formation of North Atlantic Deep Water, which causes the uneven distribution of nutrients, alkalinity, and oxygen in the deep sea today, may have been replaced by formation of North Pacific Deep Water during the last deglaciation, reversing the concentration gradients of nutrients, alkalinity, and oxygen. On a longer time scale, the present general circulation, which is dominated by production of oxygen-rich cold deep water in the subpolar regions today, may have replaced a pre-Oligocene general circulation in which warm, saline, oxygen-poor deep waters were formed in warm seas in the arid zones. Paleoceanography is still in its infancy; many new clues to the history of the ocean are being discovered, and many new ideas about conditions in the past are being developed. The beginning of the next century should see continuing rapid growth and maturation in this exciting new field.

Description: Sharp jumps in climate punctuate the records from borings in the Greenland ice cap during the time interval 60,000 to about 20,000 yr ago. Rapid fluctuations are also seen in foraminifera records for cores from the northern Atlantic and in a pollen record from a core from a bog in the Vosges Mountains in France. In this paper we present a new radiocarbon chronology for northern Atlantic deep-sea core V23-81 which permits comparison with the radiocarbon-dated Vosges Mountains pollen record. Because of the lack of a 14C chronology for the Greenland ice record and of distortions peculiar to each of the three records, it is not yet possible to say whether or not the events are genetically related.

Description: As a test of the reliability of paleocean ventilation rates reconstructed from radiocarbon age differences between planktonic and benthic foraminifera, measurements have been made on coexisting species of planktonic foraminifera. While ideally no differences should exist, we do find them. In this paper we discuss the possible causes for these differences and attempt to evaluate their impact on the interpretation of benthic-planktonic age differences.

Description: Sequence-stratigraphic concepts are used to identify genetically related strata and their bounding regional unconformities, or their correlative conformities, in seismic, well-log, and outcrop data. Documentation and age dating of these features in marine outcrops in different parts of the world have led to a new generation of Mesozoic and Cenozoic sea-level cycle charts with greater event resolution than that obtainable from seismic data alone. The cycles of sea-level change, interpreted from the rock record, are tied to an integrated chronostratigraphy that combines state-of-the-art geochronologic, magnetostratigraphic and biostratigraphic data. In this article we discuss the reasoning behind integrated chronostratigraphy and list the sources of data used to establish this framework. Once this framework has been constructed, the depositional sequences from sections around the world, interpreted as having been formed in response to sea-level fluctuations, can be tied into the chronostratigraphy. Four cycle charts summarizing the chronostratigraphy, coastal-onlap patterns, and sea-level curves for the Cenozoic, Cretaceous, Jurassic, and Triassic are presented. A large-scale composite-cycle chart for the Mesozoic and Cenozoic is also included (in pocket). The relative magnitudes of sea-level falls, interpreted from sequence boundaries, are classified as major, medium, and minor, as are the condensed sections associated with the intervals of sediment starvation on the shelf and slope during the phase of maximum shelf flooding during each cycle. Generally, only the sequence boundaries produced by major and some medium-scale sea-level falls can be recognized at the level of seismic stratigraphic resolution; detailed well-log and/or outcrop studies are usually necessary to resolve the minor sequences.

Description: Benthic octopods were collected during a bottom trawl survey on the western shelf of Elephant Island (South Shetland Islands, Antarctica) in mid-March 1981. Twelve hauls between 68 and 470 m yielded five species; most abundant was Pareledone Charcot/ (n = 114 or 50.2% of individuals) followed by P. polymorphe (n = 55 or 24.2%) and P. turqueti (n = 47 or 20.7%). Another species of the genus Pareledone not yet identified and one species of the genus Benthoctopus were present with 7 (3.1%) and 4 (1.8%) individuals, respectively. In Pareledone Charcoti, wet weight ranged from 1.8 to 136.1 g in specimens of 2.1 to 8.2 cm mantle length. Wet weight ranged from 9.8 to 164.6 g in Pareledone polymorphe of 3.1 to 9.7 cm ML. Pareledone turqueti weighed 5.3 to 275.4 g wet weight and were 2.9 to 14.1 cm in ML. The largest specimen recorded was a female P. turqueti of 6907 g wet weight and 22.5 cm ML. In general, fecundity was low and egg size large when compared to other octopodid species from temperate and warmer seas. Fecundity of females was highest in one of the smaller species, P. polymorphe. From the large variation of the gonad index and the size/frequency distribution of ova as well as from the morphology of gonads, there was evidence that spawning in mid March had already commenced.

Description: Since the mid-19th century biologists have considered the east tropical Pacific to be a barrier for the dispersal of coastal marine invertebrate species. More recently it has been maintained that this is so because planktonic larvae are unable to cross such a large expanse of ocean. Therefore, it seems extraordinary that no observations have been made to determine whether larvae of invertebrates are actually transported by the major currents of that region. Plankton samples in the present study show that invertebrate larvae do occur within the east tropical Pacific including, but not restricted to, those of gastropods, polychaetes, sipunculans, decapod crustacea, echinoderms, and coelenterates-though as a rule, their occurrence there is significantly less than within the central tropical Pacific. Data from larval distributions suggest that the east tropical Pacific may act as a substantial impediment to many invertebrate forms, but that it is not a complete barrier to dispersal. Accordingly, the region is best considered a filter. It allows only species with a potential for an exceptionally long larval life to pass i.e., those with teleplanic larvae, while it blocks other forms that are restricted to a shorter time in the plankton owing to an inability to delay metamorphosis or lack of an alternate mode of dispersal. The capacity for dispersal by planktonic larvae differs among the various taxa.

Description: Some 428 squid specimens removed from 172 samples of lancetfish and tuna stomachs are identified into 27 "species" of 10 families. The result represents micronektonic squid fauna in the tropical Indian Ocean and Southwest, Central and Sautheast Pacific regions. Morphological observation, measurements and taxonomical notes on every species are given. A few new distributional records are found from the present materials.

Description: Feeding strategies are different when adult Illex illecebrosus prey on large (trout) and small fish (mummichogs). Attacks on trout are characterized by (1) rotation as the squid changes from tail‐first to head‐first swimming; (2) an approach phase involving rapid acceleration towards the prey; (3) a tracking phase where the squid slowly follows the trout; (4) the capture phase. No tracking phase is present in attacks on mummichogs. These differences in feeding strategies can be explained by performance limitations of the squid jet propulsion system. Head‐first acceleration rates in Illex are low (max. = 12 m • s−2) and maneuverability poor compared to fish. A large fish could thus out‐perform an attacking squid if forced into evasive action. The tracking phase is a type of oceanic stalking strategy designed to bring the squid into close proximity to larger fish. The behaviour is not necessary when attacking small fish due to their low swimming speeds.

Description: The total mass of sediments on the ocean floor is estimated to be 262 × 1021 g. The overall mass/age distribution is approximated by an exponential decay curve: (11.02 × 1021 g)e−0.0355t Ma. The mass/age distribution is a function of the area/age distribution of ocean crust, the supply of sediment to the deep sea, and submarine erosion and redeposition. About 140 × 1021 g of the sediment on the ocean floor is pelagic sediment, consisting of about 74% CaCO3, with the remainder opaline silica and red clay. Of the sediment on the ocean floor, 122 × 1021 g is detritus, mostly terrigenous, but a small portion (about 6 × 1021 g) is volcanic. Because very little pelagic sediment is obducted, virtually all of the pelagic sediment mass and some fraction of the terrigenous sediment is being subducted at a rate estimated to be about 1 × 1021 g per million years. The composition of sediment on the ocean floor differs significantly from that of average passive margin and continental sediment, so that the loss of ocean floor sediment through subduction may drive the composition of global sediment toward enrichment in silica, alumina, and potash and toward depletion in calcium.

Description: Young Sepia officinalis (0-5 months) were studied in the laboratory and in the sea, and their appearance and behaviour compared with that of adult animals. Cuttlefish lay large eggs and the hatchlings are miniature replicas of the adults. From the moment of hatching they show body patterns as complex as those of adults and far more elaborate than those shown by most juvenile cephalopods. There are 13 body patterns: 6 of these are `chronic' (lasting for minutes or hours) and 7 are `acute' (lasting for seconds or minutes). The patterns are built up from no fewer than 34 chromatic, 6 textural, 8 postural and 6 locomotor components, used in varying combinations and intensities of expression. Nearly all these components occur in young animals: 26 of the chromatic, all the textural and locomotor, and 6 of the postural components. Nevertheless, patterning does change with age and we have recorded this and correlated the changes with behaviour. The components are built up from units, which themselves comprise four elements organized in precise relation to one another: chromatophores, iridophores, leucophores and skin muscles. The chromatophores are always especially important: they are muscular organs innervated directly from the brain and controlled ultimately by the highest centres (optic lobes). The areas in the Sepia brain that control patterning are already well developed at hatching, for the appearance of the skin is as much part of the brain's motor program as is the attitude of the arms or fins, or the posture of the entire animal. The iridophores and leucophores develop later and are especially important constituents of many adult patterns, notably the Intense Zebra of the mature male. Experiments confirm that patterning is neurally controlled and apparently mediated exclusively by the visual system. Young cuttlefish use patterning primarily for concealment, utilizing such strategies as general colour resemblance, disruptive coloration, obliterative shading, shadow elimination, disguise and adaptive behaviour. Older animals also conceal themselves but increasingly use patterns for signalling, both interspecifically (warning or `deimatic' displays) and intraspecifically (sexual signalling). Laboratory-reared cuttlefish were released in the sea and observed underwater. They quickly and effectively concealed themselves on the substrate; it was easy for the human observer to lose them and many passing fish behaved as if they were not there. One local predator, Serranus cabrilla, was observed to attack them and no fewer than 35 attacks were recorded, only six of which were successful. Laboratory-reared cuttlefish apparently distinguished between these predators and other, non-predatory, fish the first time they encountered them in nature.

Description: Lolliguncula brevis Blainville is a small euryhaline squid found at temperatures between 11 and 31 °C. Changes in VO2, heartbeat and ventilation frequencies were observed throughout this temperature range and under a variety of conditions, including acute hypoxia and swimming by jet propulsion in a tunnel respirometer. Resting VO2 showed a Q10 of 1.47, and heart rate and ventilation rate Q10 values of 1.92 and 1.73, respectively; oxygen uptake could exceed 1.01kg−1h−1 at 30°C even at rest. The squids regulated their oxygen uptake at all temperatures. Oxygen extraction rates were in the region of 5–10% in saturated water, increasing to 15–20% in hypoxic water or after exercise. One effect of this variability is that ventilation stroke volume can remain constant throughout the range of temperatures and oxygen concentrations that the animal is likely to encounter, a necessary condition since the ventilation stream is also the principal mode of locomotion by jet propulsion. Blood oxygen-carrying capacity (from the copper concentration) was 4.6 ± 1.8vols%. Cardiac output and stroke volume were estimated from the observed VO2 values and heartbeat frequencies. Resting at 25°C, the output was close to 11.51kg−1 body mass h−1. The systemic heart of Lolliguncula weighed only 2.06 ± 0.62 g kg−1. In exercise the cardiac output must exceed 14×103 1kg−1 heart mass h−1, pumping more than the heart's own mass of blood at each stroke.

Description: Oxygen consumption and ammonia excretion rates were investigated in young Octopus maya (hatching to 139 days old; 0.11–81.23 g wet body weight, BW; 22.5–23.9°C), young squids of Loligo forbesi (hatching to 45 days old; 9.4–115.3 mg BW; 12.3–13.1°C) and young squids of Lolliguncula brevis (2.00–39.98 g BW; 23.8–24.7°C). Except at hatching, oxygen consumption and ammonia excretion rates on an individual basis (M) of these three cephalopods increased linearly with increasing body weight (BW) expressed as M = aBWb . Values of b for oxygen consumption were 0.900, 0.910 and 0.848 and for ammonia excretion were 0.744, 0.809 and 0.751 for O. maya, L. forbesi and L. brevis, respectively. Among the three species the value a varied widely, while b was similar for both oxygen consumption and ammonia excretion rates. Based upon these data, metabolism for hatchlings of O. maya and L. forbesi was estimated to be relatively lower than that of older juveniles. The O/N ratios for hatchlings of O. maya and L. forbesi were relatively high and indicate an apparent dependence upon lipids in the immediate post‐hatching period, followed by standard protein energy utilization thereafter.

Description: Many cephalopods have lines of ciliated cells on their head and arms. In the cuttlefish Sepia and the squid Lolliguncula, electrophysiological recordings clearly identify these epidermal lines as an invertebrate analogue to the mechanoreceptive lateral lines of fish and aquatic amphibians and thus as another example of convergent evolution between a sophisticated cephalopod and vertebrate sensory system. Stimulation of the epidermal lines with local water displacements, generated by a vibrating sphere, causes receptor potentials that have many features known from lateral line microphonic potentials. The minimal threshold of the head lines is 0.2 micron peak-to-peak water displacement (calculated at the skin surface) at 75-100 Hz.

Description: Chromatophore motoneurones in Lolliguncula brevis are known to originate in the suboesophageal lobes of the brain and to project directly to the mantle and fin through bilateral stellate ganglia and fin nerves. The chromatophore motor fields of stellar and fin nerves were investigated by stimulation of the cut end of individual nerves in a semi-intact preparation. This elicited expansion of yellow and brown chromatophores in distinct motor fields. Brown chromatophores extended over the entire mantle, whereas yellow chromatophores were limited to the dorsal and lateral mantle areas. Combined nerve stimulation and lesions demonstrated substantial overlap between adjacent chromatophore motor fields and innervation of individual chromatophores by different stellar nerves.

Description: Laboratory culture of 40 Octopus bimaculoides from April 1982 to August 1983 through the full life cycle at 18°C vs 23°C provided information on the growth, reproductive biology and life span of this California littoral octopus. At 18°C, the cephalopods grew from a hatchling size of 0.07 g to a mean of 619 g in 404 d; the largest individual was 872 g. Octopuses cultured at 23°C reached their highest mean weight of 597 g in 370 d; the largest individual grown at this temperature was 848 g after 404 d. Growth data revealed a two-phase growth pattern: a 5 mo exponential phase followed by a slower logarithmic (power function) phase until spawning. At 5 mo octopuses grown at 23°C were over three times larger than their 18°C siblings. However, beyond 6.5 mo, growth rates were no higher at 23°C than at 18°C. At 13.5 mo, the mean weight of the 18°C group surpassed that of the 23°C group. The slope of the length/weight (L/W) relationship was significantly different for the two temperature regimes, with the 23°C octopuses weighing 18% less than their 18°C siblings at a mantle length of 100 mm. Females weighed more than males at any given mantle length. Males grew slightly larger and matured before females. The L/W relationship indicated isometric body growth throughout the life cycle. Higher temperature accelerated all aspects of reproductive biology and shortened life span by as much as 20% (from approximately 16 to 13 mo). O. bimaculoides has one of the longest life cycles among species with large eggs and benthic hatchlings. Extrapolations to field growth are made, and the possible effects of temperature anomalies such as El Niño are discussed.

Description: An analysis of published results on the dispersion behavior of SOFAR floats indicates a systematic depth dependence of the mixing length in the North Atlantic subtropical gyre. In contrast to the integral time scale, the length scale appears to be independent of eddy intensity in the thermocline (Lx, Ly ∼ 80, 45 km) and in the deep ocean (Lx ∼ Ly : 20 – 30 km). A similar decrease with depth is revealed by particle dispersion in an eddy-resolving circulation model and interpreted as an enhanced effect of wave behavior in the weaker, subthermocline flow. The only weak anisotropy of deep float dispersion suggests an influence of bottom roughness on the structure of eddy variability.

Description: Sequences and products of the Izu-Oshima 1986-1987 eruptions which started on November 15, 1986, were investigated tephrochronologically. The results are summarized as follows : 1) Summit eruptions (Crater A) During 15-20, Nov. 1986, Strombolian eruptions continued to make a lava lake from where lava flows spilt over and went down the slope of the central cone to the caldera floor (LA I～IV). Volcanic ash and scoria (TA-1～4) were dispersed to the eastern and western parts of the island. On 21 Nov., a little after the beginning of the fissure eruption (Craters B), Strombolian eruptions were reactivated and ejected large volcanic bombs and scoria (TA-5) from Crater A. On Dec. 18, 1986, small explosion occurred from the Crater A for three or four hours, ejecting a scoria fall (TA-6) and bomb. The level of the lava lake lowered about 5 meters. On Nov. 16, 1987, a phreatic explosion occurred to break the crust of the lava lake, and the lava drained back to the deep on Nov. 18. 2) Fissure eruptions in the caldera floor (Craters B) At 16 : 15, on Nov. 21, 1986, fissure eruptions (Craters B) started on the caldera floor and extended to the slope of the central cone. The eruptions became explosive one, generating lava fountains with the height of more than 1500 meters, with a high discharge rate of 8×106 ton/hour, producing pyroclastic cones and rootless (clastogenic) lava flows (LB I and III). Subplinian scoria falls were dispersed to west (TB-1) and east (TB-2). About 5 hours after the beginning, the activity waned to produce only volcanic ash (TB-3 and -6) and finer scoria falls (TB-4 and -5) and ceased on Nov. 23. A rheomorphic lava flow (LB II) occurred from the edge of the deformed cone on Nov. 23. 3) Fissure eruptions on the somma slope (Craters C) At 17 : 45, on Nov. 21, 1986, fissure eruptions occurred on the somma slope, and produced two lava flows (LC I and II), scoria cones, and vesicular scoria falls (TC-1 and -3) from the 11 craters. 4) The 1986 eruptions ejected 0.053 km3, 7.9×107 tons of lava and pyroclasts from A, B and C craters (Table 4).

Description: Schlußbericht für das Projekt Bu 548/1-/1-3 im SPP "Antarktisforschung" der Deutschen Forschungsgemeinschaft

Description: This investigation contribute to our knowledge of the pigment content of certain previously described Cyanophycea found in symbiotic association with sponges and ascidians (Duclaux, 1977; Lafargue and Duclaux, 1979). It is opportunity to test the hypothesis of a single symbiont Synechocystis trididemni Lafargue and Duclaux associated both with Trididemnum cyanophorum Lafargue and Duclaux and T. tegulum. Phycoerythrin characteristics suggest that T. cyanophorum contains a cyanophyte symbiont which is different from the cyanophyte symbiont of T. tegulum.

Description: This is the first report of Prochlorophyta in association with the genus Polysyncraton, a Didemnid Ascidian (Tunicata). The species P. bilobatum Lafargue, 1968 is common near Galapagos islands as well on the European and the West-African coasts. It is a key species in the evolutive line of the Didemnidae in the French coast and probably in the world.

Description: Sedimentological, isotopic and magnetostratigraphic investigations of Ocean Drilling Program and Deep Sea Drilling Project sites 642, 643, 644 and 610 document the oceanographic and climatic evolution of the Norwegian Sea and the northeastern Atlantic over the last 2.8 m.y.. The results show that a major expansion of the Scandinavian Ice Sheet to the coastal areas took place at about 2.56 Ma. Relatively severe glacials appeared until about 2 Ma. The period 2.6 ‐ 1.2 Ma experienced in general cold surface water conditions with only a weak influx of temperate Atlantic water as compared with late Quaternary interglacials. The Norwegian Sea was a sink of deep water through this period but deepwater ventilation was reduced and calcite dissolution was high compared with the Holocene. Deep water formed by other mechanisms than it does today. Between 2 and 1.2 Ma the glaciations in Scandinavia were small. A transition toward larger glacials took place during the period 1.2 to 0.6 Ma, corresponding to warmer interglacials and reduced calcite dissolution. Only during the last 0.6 m.y. has the oceanographic and climatic system of the Norwegian Sea varied in the manner described in previous studies of the late Quaternary. A strong thermal gradient was present between the Norwegian Sea and the northeastern Atlantic during the Matuyama (2.5–0.7 Ma). This is interpreted as a sign of a more zonal and less meridional climatic system over the region compared with the present situation.

Description: A worldwide investigation of continental erosion is carried out by the study of large drainage basins, on the basis of hydrological data, environmental factors, and basin relief distribution. Inside each basin, mean geochemical and mechanical denudation rates are defined. A multicorrelation analysis shows that the mechanical denudation rates Ds are uncorrelated with environmental factors and correlated with mean basin elevation H, while chemical denudation rates Dd are insensitive to relief but correlated with mean annual precipitation. Furthermore, two linear relationships between H and Ds are detected: (1) Ds (m/10³ yr) = 419×10−6 H (m) ‐ 0.245, with V (explained variance) = 95.1%; this law concerns basins related to orogenies younger than 250 Ma. The negative intercept is interpreted as a continental sedimentation rate of 245 m/m.y. An alternative model in which one invokes a critical elevation, separating erosion from sedimentation, is equally successful and leads to lower sedimentation rates (60–110 m/m.y.). For both models, one derives from the slope of the adjustments, erosion time constants on the order of 2.5 m.y. (2) Ds (m/10³ yr) = 61×10−6 H (m), with V = 86.5%; this law concerns basins related to older orogenies. The null intercept suggests the lack of continental storage. Because of the more important dispersion of the data, the erosion time constant is calculated separately for each basin; it ranges from 15 to 360 m.y. The tectonic implications of these results are discussed. In particular, the short time constant 2.5 m.y. agrees with orogenic uplift rates on the order of 1 mm/yr, observed in active mountain chains.

Description: A stress‐strain model is developed for concrete subjected to uniaxial compressive loading and confined by transverse reinforcement. The concrete section may contain any general type of confining steel: either spiral or circular hoops; or rectangular hoops with or without supplementary cross ties. These cross ties can have either equal or unequal confining stresses along each of the transverse axes. A single equation is used for the stress‐strain equation. The model allows for cyclic loading and includes the effect of strain rate. The influence of various types of confinement is taken into account by defining an effective lateral confining stress, which is dependent on the configuration of the transverse and longitudinal reinforcement. An energy balance approach is used to predict the longitudinal compressive strain in the concrete corresponding to first fracture of the transverse reinforcement by equating the strain energy capacity of the transverse reinforcement to the strain energy stored in the concrete as a result of the confinement.

Description: Abschlußbericht des Vorhabens Th 200/ 2-1 (Kennwort SEDIMENTE NORWEGEN)

Description: GEOMAR was founded in June 1987 as an institution dedicated to marine geosciences and technological development. The institution consists of three interacting organizations: the Research Center for Marine Geosciences, the “Technologie GmbH,” and the Technology Park. The GEOMAR Research Center for Marine Geosciences is central to this new institution. The director of the Research Center is Joern Thiede.

Description: On the shelf and upper slope off Peru the signal of coastal upwelling productivity and bottom-water oxygen is well preserved in alternately laminated and bioturbated diatomaceous Quaternary sediments. Global sea-level fluctuations are the ultimate cause for these cyclic facies changes. During late Miocene time, coastal upwelling was about 100 km west of the present centers, along the edge of an emergent structure that subsequently subsided to form the modern slope. The sediments are rich in organic carbon, and intense microbially mediated decomposition of organic matter is evident in sulfate reduction and methanogenesis. These processes are accompanied by the formation of diagenetic carbonates, mostly Ca-rich dolomites and Mg-calcites. The downhole isotopic signatures of these carbonate cements display distinct successions that reflect the vertical evolution of the pore fluid environment. From the association of methane gas hydrates, burial depth, and low-chloride interstitial fluids, we suggest an additional process that could contribute to the characteristic chloride depletion in pore fluids of active margins: release of interlayer water from clays without a mineral phase change. The shelf sediments also contain a subsurface brine that stretches for more than 500 km from north to south over the area drilled. The source of the brine remains uncertain, although the composition of the oxygen isotopes suggests dissolution of evaporites by seawater.

Description: The southern section of the Agulhas western boundary current system exhibits unique characteristics as regards ocean/atmosphere heat flux processes. The Agulhas Retroflection region's high heat flux core from 37°S to 41°S, 16°E to 22°E does not demonstrate a distinct annual cycle of turbulent heat fluxes (latent and sensible) as is characteristic of its northern hemisphere counterparts. Rather, a weak semiannual heat flux cycle is found with maximum average losses during winter and summer (200 and 211 W/m2 ) and minimum losses during spring and autumn (185 and 162 W/m2 ). Upstream where the Agulhas Current is closer to land, winter heat losses exceed those of summer, but the differences are small. This behavior contrasts with that encountered at the poleward ends of northern hemisphere western boundary currents where winter heat fluxes are several times those of summer. The main reason for this difference is persistent westerly and southwesterly wind flow over the Agulhas Retroflection region throughout the year which ensures that cold, unsaturated maritime air repeatedly forces loss of heat from the ocean's surface. Spatial heat flux gradients associated with the Agulhas‐Subtropical Convergence surface temperature front are more pronounced in summer than in winter, indicating that cyclogenesis locally may be less seasonally dependent than in the northern hemisphere situation. Average oceanic cooling rates in the core region of the Retroflection, based on net heat flux calculations and a mixed surface layer of 75 m, range from 1.35°C/month during winter to 0.25°C/month during summer. Interannual variability in ocean/atmosphere heat fluxes within the Agulhas Retroflection region often exceeds the variability illustrated by the annual cycle. West of the Agulhas Retroflection core region, interannual sea surface temperature (SST) anomalies are more influential in the generation of heat flux anomalies by virtue of their large temporal variability. This high SST variability is primarily attributed to interannual changes in flux of Agulhas Current water into the southeast Atlantic Ocean. Oceanic heat loss within this warm water zone is an important modifying influence to both ocean and atmosphere, thus meriting further research.

Description: 1. Analysis of cine films and intramantle pressure records for squid Loligo opalescens Berry swimming in a tunnel respirometer provided estimates of all the forces acting in the horizontal and vertical planes for swimming speeds from 0.1 to 0.5 ms−1. 2. Different speeds used different gaits; fin thrust was only important below 0.2 ms−1, ‘anaerobic’ circular muscles were recruited only at supracritical speeds, and hyperinflation caused by contraction of the radial muscle was not seen in steady swimming. 3. The extent, rate and frequency of contraction of the obliquely striated circular muscles varied little with speed, and jet thrust was matched to speed primarily by active pressure control through adjustments in the size of the funnel orifice. 4. Hydrodynamic lift production to compensate for negative buoyancy during enforced horizontal swimming in the tunnel required 30–90% of the total force over the speed range studied and appears less efficient than direct use of jet thrust. This suggests a new rationale for ‘climb-and-glide’ swimming which reduces previous estimates of the gross cost of transport for squid under natural conditions by at least 35%, with no loss of speed. 5. The cost of accelerating water into the mantle of a squid moving at high speed appears to have been underestimated in previous studies. A simulation of a series of escape jets predicts a maximum speed of 8 body lengths s−1 (1.4ms−1), reached after only two jets, because of the high deceleration during refilling.

Description: Using seabirds as sampling devices on two cruises in the northwestern Weddell Sea, we investigated the species and lengthfrequency distribution of micronekton in surface waters. Our micronekton samples are among the first ever collected simultaneously in both ice-covered and adjacent ice-free waters in the Antarctic using the same technique. Changes in the abundance or presence of certain crustacean, squid, and fish species were related to the presence of ice, and to distance from the ice edge. Length-frequency distributions representing age- or sex-classes of fish and krill were also affected by proximity to the ice edge. Our data indicate that the proximity of sampling to pack ice may affect our perception of the composition of micronektonic communities, and that the marginal ice zone is an important area for juvenile age-classes of pelagic fish and krill.

Description: This chapter deals with information on the role of squid, and on feeding by sperm whales on squid, in the Antarctic. Seasonal variation in the vertical distribution of krill swarms may possibly affect the distribution of smaller squid which feed on krill. Larger squid are distributed in deeper water layers where they do not feed on krill alone. Sperm whales eat larger squid in the deeper waters of the Southern Ocean. The diet of these larger squid is unknown. It is suggested that the food chain from krill to sperm whale has several links, including fish and squid. The importance of studies on deep-sea systems in the Southern Ocean is emphasized.

Description: The 100 ka rhythm of orbital eccentricity has dominated large-amplitude climatic variations in the high-latitude North Atlantic during the Brunhes magnetic chron (0-0.735 Ma BP). Earlier, during the Matuyama chron (0.735-2.47 Ma BP), climatic variations in this region were lower in amplitude and concentrated mainly at the 41 ka rhythm of orbital obliquity. These rhythmic climatic responses to orbital forcing are evident both in stable isotopic (δ18O) indicators of ice volume or temperature and in biotic and lithologic indicators of local North Atlantic surfaceocean variability. The synchronous responses of these indicators are consistent with results from atmospheric general circulation models showing that the North American ice sheet directly controls North Atlantic surface-ocean responses via strong cold winds that are generated on the northern ice-sheet flanks and blow out across the ocean, chilling its surface. Before 2.47 Ma BP, smaller-scale quasiperiodic oscillations of the planktonic fauna and flora occurred, but the cause of these variations in the absence of significant ice sheets is unclear.

Description: Age and growth were estimated on two brood stocks of a loliginid squid, Photololigo edulis (Hoyle), by examining growth increments within the statoliths from 773 specimens. Samples were collected from the northwestern coast of Kyushu, Japan, and the southwestern coast of the Sea of Japan between January 1983 and June 1984. Length and age data were fitted to logistic growth curves for each sex and brood, under the assumption that increments formed daily. Relationships between age and mantle length and the modelled growth curves showed that: the posthatch life span may be 〈 1 yr; growth rates vary considerably between individuals, especially in the second half of life; the average growth rate of the male was higher than that of the female in the warm-season brood, but almost the same in the cold-season brood. Because of the wide variation in the individual growth rate, it was presumed that warm- and cold-season broods were not genetically discrete populations.

Description: The migration pattern of Illex argentinus in the waters off Argentina was estimated based on the data collected by research survey from April 1978 to April 1979 and on fisheries statistics of Japanese commercial vessels. In spring of the Southern Hemisphere juvenile squid appear in the northern half of the Patagonian Shelf excluding the area covered by the coastal waters. They disperse gradually towards offshore and southern waters, and spread their habitat to almost the entire shelf by summer. In autumn they move towards the east (the edge of the shelf) and north and aggregate on the slope of 400-700m in depth for some time in the north and middle parts of the shelf. Then they leave the slope probably for spawning in winter.

Description: Es wurde in dieser Arbeit gezeigt, daß der Abriß des Segels das Verhalten der Driftbojen grundlegend verändern kann. Ohne Segel zeigen die hier untersuchten Drifter erhebliche Windabhängigkeit, während sie mit Segel weitgehend der Strömung in Segeltiefe folgen. Dies gilt sicherlich für die in 100 m Tiefe besegelten Bojen, aber es existieren auch Hinweise darauf, daß auch die Bewegung der Deckschicht nur mit Segeln richtig wiedergegeben wird. Es ist deshalb nötig, die Drifterdaten vor einer weiteren Auswertung zu bereinigen, d.h. den Datensatz in einen Teil mit und einen Teil ohne Segel aufzuspalten. Mit Hilfe einiger ausgewählter Drifter ließen sich charakteristische Unterschiede zwischen Bojen mit und ohne Segel feststellen, die es ermöglichen, den Abrißtermin in den Drifterzeitreihen zu finden. In den hier betrachteten Fällen läßt sich der Verlust des Segels anhand der Driftgeschwindigkeiten, Varianzen, Beschleunigungen und monatlichen Spektren erkennen, wenn als Zusatzinformation noch die Driftbahn und die mittleren Deckschichttiefen hinzugezogen werden. Als Test für den so bestimmten Segelabriß eignen sich der Windvergleich und die Aufspaltung in Vor- und Nach-Abrißdaten. In Gebieten mit geringer mittlerer Strömung scheint diese Methode erfolgreich zu sein. Ob sie auch im westlichen Randstrom funktioniert, muß sich noch zeigen.

Description: This study is concerned with the influence of wave disturbances on deep convective cloudiness over the African continent and the adjacent Atlantic Ocean in the region of the ITCZ. It is supposed, that the growth of cloud clusters is stimulated by wave disturbances. The diurnal march of cloudiness can be intensified or suppressed by convergence and divergence of these disturbances. For this study IR- satellite pictures (METEOSAT 1) from May 2 until July 3, 1979 are used to construct Hovmoeller-diagrams and to derive time records of cloud cover for 2.5° *2.5° areas. The Hovmoeller-diagrams show a systematic westward motion of cloud clusters more frequently in June than May. Some of these cloud systems are connected with the 6 easterly waves derived by EBERZ (1987). In most cases the position of the wave trough is found west of the clusters. From the Hovmoeller-diagrams in can be concluded, that the other moving cloud systems are also connected with wave disturbances. A spectral analyse of the time records is performed, the statistical significance of the results is weak. Different periods of cloudiness for the ocean and continent are found. For periods greater than 8 days the spectral variance over the ocean is much larger than over the continent. Over the west african coast the coherence analysis shows an east-west orientated wave track for periods in the domain of 3 days and a northeast-southwest orientated wave track for periods in the domain of 10 days.