The role of this group of organisms in the ecology of the sea is incompletely understood. Individuals are usually rare and oceanographic investigators seldom find them at all in the catches of their tow nets. As a consequence, they do not appear in many of the statistical results of such studies. The members of the four known living genera form a part of the surface plankton, so far as the records show, but more specimens have been found in the bottom deposits where they presumably have accumulated by settling. Brandt (1898) on March 15, 1893 found 250,000 cells of Distephanus speculum among 3,173,564,000 total organisms in a collection from the Bay of Kiel. Gran (1915) on October 20, 1907, found 50,400 of the same species per liter of water at the surface in Oslo-Fjord. In various comprehensive reports on plankton this species is reported as being sparse, or in concentrations of a few hundred to a few thousand cells per liter, but there seems to be no consistent pattern to its occurrence, at least on the basis of present data. An excellent discussion of the ecology of the group was given by Gemeinhardt (1930). Deflandre (1932–1950) has added much to a clarification of the nature and ecology of the group. B orgert , A. Über Dictyochiden, insbesondere über Distephanus speculum ; sowie Studien an Phaeodarien: Zeitsch. f. wiss. Zool., vol. 51, pp. 629–676, 1 pl., 2 text figs., 1891 A detailed study of living material with a good review of preceding ...

Abstract Knowledge of oceanic sediments has been acquired in two ways: 1) directly by sampling and observation, and 2) indirectly through seismic investigations. Until the past decade, direct sampling and observation techniques could only provide information on the surficial materials of the ocean floor. The development of the piston corer (Kullenberg, 1947) has permitted oceanographic vessels to sample the upper 20 meters, and more recently the upper 30 meters, of the ocean floor, but such cores rarely penetrate the Pleistocene and enter older sediments. Until recently, most knowledge of the deeper sedimentary materials in the ocean basins was obtained through seismic reflection studies (Ewing and Ewing, 1970). Since the early part of the last decade, the development of deep ocean drilling techniques has permitted sampling of the sediments of the oceans to depths in excess of 1,000 meters. Starting with the experimental Moholes drilled off Southern and Baja California (AMSOC Committee, 1961) the recovery of cores taken using oil-field drilling techniques has been increasingly successful. To plan a large scale program of deep sea drilling, several major oceanographic institutions formed an organization known as JOIDES (Joint Oceanographic Institutions Deep Earth Sampling). The original JOIDES members were Woods Hole Oceanographic Institution, La-mont-Doherty Geological Observatory of Columbia University, Rosenstiel School of Marine and Atmospheric Science of the University of Miami, and Scripps Institution of Oceanography of the University of California at San Diego; the Department of Oceanography of the University of Washington, joined subsequently. Scripps Institution of Oceanography submitted the proposal for ocean drilling and manages the program. Known as the Deep Sea Drilling Project, this program has been in effect since 1967, and is expected to continue through the summer of 1975, with the funding being provided by the National Science Foundation. In the early phase of the Deep Sea Drilling Project areas under investigation were limited to the tropical and subtropical regions of the Atlantic and Pacific Oceans. Since 1970, the deep sea drilling vessel Glomar Challenger has made excursions into higher latitudes, and will investigate the Southern Ocean during the coming austral summers. During 1971-1972, the Glomar Challenger drilled and cored a number of sites in the Indian Ocean, and by the end of the project there will have been reconnaissance drilling in all of the oceans except the Arctic.

INTRODUCTION In this chapter we are concerned primarily with the methods of observing and obtaining marine organisms as the most essential part of ecological investigations. The section on Sampling the Benthos has been prepared by Gunnar Thorson, that on Dredges and Trawls by Gordon Gunter. There are several comprehensive works, in addition to their appropriate chapters in standard texts, dealing with instruments and their uses, the most recent of which are Welch’s Limnological Methods (1948), the Russian volume on Oceanographic instruments by Snezhinskii (1951), and the National Research Council Symposium volume on Oceanographic Instrumentation (Isaacs and Iselin, 1954). See also the symposium at the 1953 British Association meeting (Barnes et al., 1953). Since the techniques of observation on the shore are essentially those of terrestrial ecology, there is little need to mention them here. (See, for example, Hewatt, 1937; Dexter, 1943.) We do not intend to minimize the importance of physical and chemical data in ecological investigations, of course, but it must never be forgotten that an ecological investigation is essentially an investigation of organisms in situ, and physical and chemical information without specific reference to organisms is the stuff of meteorology and hydrography, not ecology. The primary data of any ecological investigation, therefore, are the species of organisms concerned. These data may be represented by actual specimens retained in a collection, measurements of specimens which are returned to the environment or processed in some way (as in a fisheries), observation of specimens without more than passing note (“sight records”),...

Abstract The Messina Strait is a c. 3–8 km-wide and 40 km-long extensional area that connects the Tyrrhenian Sea with the Ionian Sea (Mediterranean Sea), and where tectonics, oceanographic and erosive-depositional downslope processes strongly interact with each other. Based on the analysis of high-resolution multibeam data, we present an updated morphosedimentary framework that reveals a complex seabed morphology, characterized by a variety of features linked to bottom currents and downslope processes. In particular, we recognize a suite of large- to medium-scale erosive and depositional features, related to different bottom currents (e.g. reverse tidal flows, residual flows, internal waves) acting over diverse time periods. Large-scale bottom-current features are represented by contourite drifts and channels developed over long periods (more than thousands of years). Medium-scale features formed during shorter time periods, and include scours, furrows, transverse ridges (pinnacles) and narrow longitudinal bodies in the sill sector, along with several sand-wave fields, located at greater depths on the Ionian and Tyrrhenian sides of the Messina Strait. Downslope processes encompass channelized features originated by sedimentary gravity flows, coarse-grained aprons and fans, and submarine landslides. They mostly occur along the margins of the strait and become predominant in the southern exit where the axial Messina canyon and its tributaries are present. Overall, our study shows that the Messina Strait is a fruitful area in which to investigate the interaction between recent erosive-depositional sedimentary and oceanographic processes, also modulated by sea-level fluctuations, during the last eustatic cycle. Moreover, the observed seabed morphologies and the associated processes provide insights into interpreting similar features in modern and ancient similar straits and seaways.

Abstract Bryomol carbonates, composed of bryozoans and molluscs, are found in non-tropical shelf and upper slope settings where they are sensitive indicators of oceanographic conditions. Few modern bryomol carbonate settings have been investigated to date, despite their importance in the Phanerozoic rock record. Furthermore, no detailed facies mapping and long-term oceanographic observations have been undertaken in modern bryomol settings, even though this is important for accurately interpreting facies, climate and oceanography from fossil bryomol carbonates. A bryomol carbonate factory on the western margin of the northern Gulf of California, Mexico was selected for an integrated high-resolution in situ oceanographic monitoring, acoustic seafloor mapping, sediment and bryozoan growth morphology study. Molluscan- (28%), bryozoan- (25%) and barnacle- (14%) dominated carbonate production takes place under normal saline warm-temperate eutrophic conditions, with average near sea surface temperatures of 20°C. Even though temperatures are unusually warm for the formation of bryomol carbonates, they develop as a result of prevailing eutrophic conditions (average chlorophyll- a contents of 2.2 mg chl- a m -3 ). Eutrophic conditions provide ample food to heterotrophic calcifiers and largely exclude faster-growing phototrophic organisms by drastically restricting the depth of the euphotic zone and, therefore, water clarity. Thus, the presence of high amounts of nutrients can generate cool-water-type carbonate assemblages at temperatures where a warm-water association would be expected.

Abstract More than 1700 km of high-resolution seismic data were collected over the Marion Plateau, northeast Australia, to investigate the influence of sea level and oceanography on subtropical carbonate platforms growing on the plateau surface. Seismic data, interpreted in combination with sediments recovered during Ocean Drilling Program Leg 194 and modern oceanographic data, have enabled characterization of the parameters controlling platform growth and development in this region. Most modern carbonate platforms, such as the Bahamas Platform, have sedimentation patterns that reflect the prevailing wind direction where sediments are forced off the platform on the leeward side, leaving the windward side relatively sediment-starved. This results in platform asymmetry with steep windward and gentler leeward slopes. The seismic data presented here indicate that the carbonate platforms off northeast Australia, although similar in morphology to the Bahamas Platform in many respects, are dominated by oceanographic currents as the primary energy source creating a similar asymmetrical platform geometry where the upcurrent side of the platform is relatively sediment starved and most sedimentisdepositedonthe downcurrent slope. Currents in the study area are dominated by the southward-flowing East Australian Current that generally flows opposite to the prevailing Southeast Trade Winds. This current likely determines not only the morphology, but also the growth potential of the platforms, as well as the volume and final location of sediment transported from the platform top. Despite the massive, tablelike structures exhibited in the seismic data, Leg 194 drilling demonstrated that the platforms are almost entirely composed of the remains of cool, subtropical organisms, such as red algae, bryozoans, and larger benthic fo-raminifera. Coralline algae were notably absent from most sequences. These calcite-dominated organic remains have a low diagenetic potential, resulting in uncemented and friable slope successions. Nevertheless, the platform tops are well cemented. The fact that the cool subtropical faunal assemblages produce platform geometries that are similar to tropical carbonates suggests that physical parameters, such as current flow and sea level change, may be more important than biofacies in establishing platform architectures.

Abstract In the Central Adriatic basin the late Quaternary Depositional Sequence comprises four systems tracts that vary greatly in thickness and internal geometry along the margin. Each of the systems tracts was deposited during distinctive portions of the relative sea-level curve that was dominated by the eustatic signal. This paper summarizes the physical-stratigraphic framework of late Quaternary TST deposits in the Central Adriatic area, based on the interpretation of a dense network of seismic profiles, sediment cores and accelerator mass spectrometer (AMS) 14 C dates. The Adriatic epicontinental basin includes two contrasting shelf domains: the wide and low-gradient northern shelf and the narrower and steeper central shelf surrounding a slope basin 250 m deep. A refined stratigraphic scheme of complementary shelf and deeper water records helps to recognize the influence of past environmental change on depositional systems, internal geometry, and lateral facies changes within the late Quaternary TST During the late Quaternary sea-level rise, between 16,000 and 5,500 years BP, several factors influenced the deposition of the TST in the Adriatic basin. Short-term climatic instability caused repeated changes in sediment flux, while the transgressive drowning and widening of this semienclosed basin permanently changed the oceanographic regime, which affected the mechanisms of shelf sediment dispersal. The late Quaternary TST consists of three distinctive units that are easily recognized through high-resolution seismic profiles, sediment cores, and multiproxy stratigraphic data. The middle TST unit is more complex compared to the underlying and overlying TST units, which were deposited during an interval of extreme climatic instability (between approximately 14,800 and 11300 calibrated years BP) and includes proximal progradational and distal mounded deposits on the shelf. The middle TST unit records a peak in sediment flux and mean grain size that suggest a significant change in supply regime This three-fold subdivision can be extended to the late Quaternary TST in the rest of the Adriatic basin in areas where the record is essentially composed of undersupplied and physically detached barrier-lagoon-estuary systems. These transgressive systems, which either drowned in place or were partially reworked, have no offshore muddy correlative on the northern shelf. This evidence indicates a marked longshore facies partitioning between a northern area with barrier-lagoon deposits and starved shelf and a southern area with thick and complex mud-dominated shelf units. This kind of facies partitioning was established during the deposition of the middle TST and affected the upper TST and the HST as well. Variable sediment flux and oceanographic regime affect the stratigraphic record, even during an interval of rapid accommodation-dominated cyclicity like the late Quaternary. The recognition of such factors is possible through the study of mud-dominated shelf sequences on modem margins, but it is important to consider the relevance of such factors also when interpreting ancient successions, although straightforward comparisons among modern and ancient continental-margin deposits are hampered by the different investigation techniques required and the diverse scales of observation.

Abstract The World Ocean’s 361.059 × 10 6 km 2 area covers the greater part of the earth’s surface and is 2.5 times as large as the area of land. Nearly 84 percent of the southern hemisphere is blanketed by the oceanic waters. Taken together, all the marginal and inland seas constitute another 10 percent of the World Ocean’s surface area. The continents can be thought of as huge islands in the ocean. Therefore, the oceanic processes of matter and energy transformation are of global significance. Until recently marine sedimentation and the laws of oceanic sediment distribution and composition were poorly understood because of the lack of data and samples of deep-sea sediments, and because the distribution and composition of the material suspended in water was virtually unstudied. Some parts of the oceans such as the Arctic and Antarctic were even less explored because of their inaccessibility and great distance from the countries engaged in intensive oceanographic research. The role of oceanic sediments in the history of the Earth is still not clear. However, most investigators believe that geosynclines form in the marginal regions of the ocean, and thus that old geosynclinal deposits are mainly accumulations of marine sediments. During the last few decades new materials have been obtained which must be evaluated, critically correlated and synthesized. The following are among the most important oceanographic achievements of the past several years: New data on the distribution and composition of sediments of the World Ocean have been synthesized as sediment charts for

Abstract The Bowland sub-basin is a target for hydrocarbon exploration, but to a large extent it remains unexplored. To determine the economic potential of the Bowland sub-basin, it is important to identify the oceanographic processes involved in the deposition of the Bowland Shale Formation in the Late Mississippian (c. 330 Ma). Palaeoceanographic processes are known to be a major control on the development of hydrocarbon source rocks. This study investigates core (Preese Hall-1 and Becconsall-1Z) materials from the Upper Bowland Shale, and makes a comparison with previously published data (outcrop Hind Clough), all from the Bowland sub-basin, Lancashire, UK. The sedimentology and geochemistry of this formation were determined via a multi-technique approach including X-ray fluorescence, sedimentology, gamma-ray spectra, X-ray diffraction and Rock-Eval pyrolysis. Key trace metal abundances and enrichment factors were used to assess sediment provenance and to determine the bottom-water redox conditions during the deposition of the Upper Bowland Shale. Our results support interpretations of contemporaneous anoxia developing in bottom waters in at least three sites in the Bowland sub-basin. In a comparison with the Fort Worth Basin (Barnett Shale, USA), the Bowland sub-basin was apparently less restricted and deposited under a much higher mean sediment accumulation rate. Knowledge from this study will improve future resource estimates of the Bowland Shale Formation, and challenge the early assumptions that the Barnett Shale is an analogue of the Bowland Shale.