Institute Of Oceanographic Sciences Research Articles

Sir Anthony Seymour Laughton. 29 April 1927—27 September 2019

Anthony (Tony) Laughton was an oceanographer who promoted the science of oceanograpy in Britain. Focusing on the shape of the seafloor, his work included underwater photography, ocean drilling, long-range side-scan sonar and scientific charting of the ocean floor. Following undergraduate studies at King's College, Cambridge, he joined Maurice Hill (FRS 1962) at the Cambridge Department of Geodesy and Geophysics, beginning a career in marine geophysics. Following his PhD, he spent a year at Lamont Geological Observatory, USA, where he met many leading US workers, and became interested in deep-seafloor photography and bathymetric mapping. Returning to the UK, he joined the National Institute of Oceanography (Institute of Oceanographic Sciences from 1973) at Wormley, Surrey, and became director in 1978. He developed the first UK seafloor camera, was an enthusiastic supporter and user of the revolutionary Precision Echo Sounder and later of the GLORIA long-range side-scan sonar. He played a significant part in the International Indian Ocean Expedition, subsequently developing a new understanding of the Gulf of Aden. A consummate committee man, he had a vital role in reviving the General Bathymetric Chart of the Oceans and promoted UK involvement in the international Deep-Sea Drilling Project. He was an accomplished amateur musician (playing French horn), small-boat sailor and handyman.

Professor David Gwyn Roberts – a Life in Geoscience

Abstract This conference was held to celebrate the outstanding career of a remarkable man. Professor David Gwyn Roberts was one of the most creative, productive and influential geoscientists of his generation. The range of his achievements and the scope of his influence on the world of geoscience are remarkable. He had a profound impact on geological thinking and understanding that serves as his lasting legacy. His Life in Geoscience commenced as a marine geoscientist at the Institute of Oceanographic Sciences, where he rapidly developed a global reputation for innovative research; this was followed by a highly influential spell as an explorer, technical expert and mentor in BP, and culminated in a successful career as a globally respected consultant, professor, teacher and author. He also edited numerous journals, founded the publication Marine and Petroleum Geology and held high office in a number of professional organizations. Through his lectures, workshops and courses he served as an inspiration to hundreds of geoscientists around the world. Any phase of his career would identify David Gwyn Roberts as an outstanding geoscientist. The fact that these achievements were the work of one man mark Professor Roberts's life and contribution to the geosciences as truly remarkable.

David Edgar Cartwright. 21 October 1926 — 2 December 2015

David Cartwright was one of the world's leading authorities on the tides. However, when reflecting on his life, Cartwright made the point that his early scientific career was not a success. Indeed in 1953, at the age of 27, he had virtually despaired of any creative scientific future. At the time he was being pressurized to stop his work on the statistics of ship motions but his prospects rapidly changed when he was invited to apply for a post at the new National Institute of Oceanography (NIO) being set up by George Deacon. At NIO he soon made important contributions to the study of ocean waves, especially the calculation of directional spectrum and wave climate. His earlier involvement with ship motions also culminated in a successful joint study with Louis Rydill on the response of ships to the spectrum of waves. Following this, his use of computer methods for time-series analysis led to an invitation to the Scripps Institution of Oceanography where, with Walter Munk, he developed the response method of analysing tides making use of the very long tidal records collected from Hawaii and Newlyn. He was also made aware of the significant lack of good tidal data from the deep ocean. Returning to the UK, he continued these interests, studying the deep-ocean tides of the Atlantic and leading an international collaboration that measured deep-ocean tides. He also investigated the effect of tides on storm surges around the UK. He became assistant director in charge of the Institute of Oceanographic Sciences (IOS) Bidston laboratory, where he continued these activities and started research on estimating the tides using data from the Seasat radar altimeter. After retirement he successfully extended this work with Richard Ray at the Goddard Space Flight Center. Using Geosat altimeter data they generated accurate global maps of the tides in a set of papers that Cartwright considered to be his best work. He wrote a successful book titled ‘ Tides: a scientific history ’, and later published further work with Ray on the internal tides of the ocean.

50th anniversary of Numerical Weather Prediction (NWP) in the UK

To mark the 50th anniversary of NWP in the UK, the Met Office hosted the Royal Meteorological Society's national meeting on 18 November 2015, chaired by Ken Mylne (Met Office). The Met Office's Chief Executive Rob Varley opened the meeting, saying that synoptic-scale NWP in mid-latitudes constitutes one of the crowning scientific achievements of the twentieth century. The Met Office's Chief Scientist Julia Slingo then expressed optimism about the future, and paid tribute to Malcolm Walker, Chair of the Royal Meteorological Society's History Group, who was unable to attend the meeting. The main talks covered past, present and future, with recurring themes of progress being driven by improving science and technology, significant weather and world events, the importance of translating science into services and of communicating forecasts of the weather and its impacts. Anders Persson (Uppsala University) described the pioneering men and women behind NWP in the UK between 1948 and 1965. He also contrasted the differing approaches of the UK, whose two-layer baroclinic model with associated vertical motion was needed to diagnose rainfall, with other centres in the USA and Sweden, who were initially content with simpler one-layer barotropic models. The baroclinic model's higher memory overheads led to a smaller area, which led to too rapid propagation of boundary errors, while the 2h timestep used in the numerical solver led to instability. On 2 November 1965 the new Director-General John Mason committed the Met Office to operational NWP at a press conference. Nick Grahame (Met Office) covered the next 50 years, describing the Octagon and Rectangle models, the UK's global model (operational in 1982, catalysed by the Falklands War) and ECMWF's first ensemble in 1992. He showed the first UK operational NWP forecast and included quotes from former forecasters that NWP was initially ‘a useful idea to consider’ or ‘mostly ignored’. By the late 1970s it had become an important ingredient. The Great Storm of 15/16 October 1987 motivated the creation of the National Severe Weather Warning Service and big changes in how NWP was used and forecasts communicated. The benefits of coordinated communication of weather warnings were particularly apparent in the Burns Day storm (25 January 1990). More recently, the St Jude's Day storm (28 October 2013) had its first Amber warning issued five days in advance and received much media coverage, including of the uncertainty. Peter Clark (Reading University) described convective-scale NWP. Today's forecast problems (inland shower penetration, fog etc.) involve small-scale weather and require non-hydrostatic models allowing for vertical motion when modelling convection. At kilometre scales, these models are convection-permitting, resulting in output that looks realistic but is usually wrong in detail. The Met Office's mesoscale model was developed from 1976 and was gradually introduced into operations from 1984. A non-hydrostatic dynamical core was then introduced in the Met Office Unified Model (MetUM) in 2002. The Boscastle flood on 16 August 2004 showed that the kilometre-scale configuration provided a much better representation of the rainfall than the operational 12km configuration. The MetUM was subsequently upgraded to a 4km grid in 2005 and then to the present 1.5km grid in 2010. A 300m grid was used for the Weymouth Bay sailing events in the 2012 Olympic Games, and a similar configuration is now being trialled for the London area, including Heathrow Airport. Brian Golding (Met Office) spoke about applications of NWP. The first operational application was route-planning for aviation, which required jet-stream predictions. The extraction of North Sea oil and gas led to the launch of the first swell model in 1976, which was subsequently upgraded to an ocean wave model in 1979. Likewise, the Thames Barrier construction motivated the development of the storm surge model with the Institute of Oceanographic Sciences. The MetUM now supplies rainfall output to the Centre for Ecology and Hydrology's Grid-to-Grid model for Environment Agency flood prediction. The Chernobyl nuclear accident in 1986 led to the development of the NAME model, which is used to track the spread of nuclear and chemical material, volcanic ash and airborne diseases. Health applications were also presented along with hazard forecasting, which combines the meteorological risk with the impact of an adverse outcome. The WMO's High Impact Weather initiative aims to look at all aspects of weather impacts to create a more resilient world, including evaluating what warnings to issue and whether people respond. Such risk modelling is inherently probabilistic, with ensemble forecasting at its heart. Dale Barker (Met Office) spoke about plans for the next 5 years and speculated about the next 50. Satellite data dominate other observations in their impact on forecast skill. Ensembles continue to grow in importance, but will need to be used in conjunction with deterministic models. New verification measures are being developed to better describe the added value of the UK model over the global model, which is increasingly getting better at forecasting weather parameters. Future upgrades will need to be tested over longer periods because convective-scale models are inherently variable in their skill. The Met Office is installing new supercomputer and storage infrastructure and is considering which combination of longer forecasts, larger ensembles, higher resolutions and increased complexity (e.g. coupling atmosphere and ocean) will best deliver the anticipated £2bn benefit to the UK. Improvements to data assimilation will continue, enabling hourly forecast updates. The big challenge is computer architectures, which cannot get faster at their current rate because the power consumption becomes prohibitive, so improved parallelism is the key to future performance, driving the redesign of NWP software at the Met Office. An animation of a fog forecast showing a remarkable consistency with satellite observations for 2 November 2015, exactly 50 years after Met Office operational NWP started, showed the level of progress that has been achieved. The meeting closed with a poster session showing recent developments and demonstrations of the Weather Observations Website (http://wow.metoffice.gov.uk) and Informatics Lab (http://www.informaticslab.co.uk).

THE 2010 JOSEPH A. CUSHMAN AWARD

ANDREW J. GOODAY The 2010 Joseph A. Cushman Award for Excellence in Foraminiferal Research was presented to Andrew J. Gooday on November 2, 2010 at the Cushman Foundation for Foraminiferal Research Reception and Award Ceremony in Denver, Colorado. Andy Gooday began his career studying ostracodes. His M.S. from the University of Wisconsin, Milwaukee was on Miocene benthic ostracodes and his Ph.D. from the University of Exeter (UK) was on Devonian ostracodes. The particular group that he studied in his dissertation, the entomozoids, is believed to have been plankton and so the logical next step was to work with the modern equivalents. This he did as a NERC Postdoctoral Fellow at the Institute of Oceanographic Sciences (Wormley, England), where he studied modern planktonic ostracodes under the direction of Dr. Martin V. Angel, the leading authority on this unusual group. As this fellowship was finishing, Dr. Tony Rice was starting a benthic biology working group at the same institution and Andy began working on the copious benthic foraminiferal material collected off northwestern Africa on a cruise in 1973. During this early stage of his career, Andy was employed …

Patrick Michael Holligan: a short biography

Our understanding of the role of marine phytoplankton in the global biogeochemical cycles of carbon and sulphur, particularly the rates and variability of primary production and calcification, phytoplankton activity and ecology in the subsurface chlorophyll maximum, and the use of satellite remote sensing to detect coccolithophore blooms, has progressed substantially through research initiated, led and undertaken by Patrick M. Holligan. The enthusiasm and commitment of Patrick’s colleagues for both this special issue and the symposium on “Marine Plankton: From Cells to Ecosystems” held in his honour in April 2008 at Plymouth, UK are testament to the high esteem in which he is held within the international scientific community. His expertise as a scientific leader, teacher and writer has inspired students and collaborators over more than three decades. In particular, his chairmanship during the early 1990s of the Planning Committee for the “Land-Ocean Interactions in the Coastal Zone” (LOICZ) project led to the establishment of a new core project within the International Geosphere-Biosphere Programme (IGBP). As the first Head of the School of Ocean and Earth Science (SOES), University of Southampton (1998– 2002), Patrick had responsibility for substantial expansion of the School, including 13 new academic appointments. As one of the first UK Principal Investigators to propose an open-ocean latitudinal time-series study, he helped initiate the development of the Atlantic Meridional Transect (AMT) programme (www.amt-uk. org), and as the President of the Council of the Sir Alister Hardy Foundation for Ocean Science (SAHFOS), he guided the transition to a new Directorship of the Continuous Plankton Recorder programme. Patrick gained an MA in Botany from Christs College, Cambridge in 1966. He then moved to the Department of Botany at the University of Leeds where he completed his PhD in 1970 on “Carbohydrate metabolism in the fungus Dendryphiella salina“ under the supervision of David Jennings. During the first year of his PhD, Patrick assisted Ed Drew in some research on acclimations by seaweeds to changes in light intensity and quality that required summer fieldwork in Malta. It was here that Patrick practised his self-taught skills in scuba diving, met John Woods for the first time, acted as a guinea pig for behavioural research into the effects of nitrogen narcosis, and developed a serious interest in the marine environment. While doing his PhD, Patrick also met and married his wife, Sue. Patrick then undertook a postdoctoral appointment (1969–1973) with David Lewis in the Department of Botany at the University of Sheffield to work on the physiology of higher plants infected by rust fungi. In 1973, Patrick joined the staff at the Marine Biological Association (MBA) in Plymouth UK as a Research Scientist, despite his only “marine” credentials being research on a marine fungus and his hobby of scuba diving. He sought external advice from David Cushing and Tim Wyatt at Lowestoft and from Jack Talling at Windermere about developing a new research programme on marine phytoplankton and then, over morning coffee, met Robin Pingree, a physicist with an interest in biology who had come from the Institute of Oceanographic Sciences (IOS), Wormley, UK to work

Bathypelagic pycnogonids (Arthropoda, Pycnogonida) from the Discovery deep-sea cruises

The donation to The Natural History Museum, London of the Institute of Oceanographic Sciences (IOS) Discovery collections in 1997 included pycnogonids taken in bathypelagic samples collected with a rectangular mid-water trawl. The material of Pallenopsis tritonis Hoek, 1883 in these collections has been analysed and reported elsewhere. The present paper describes the remaining trawl material. One new species of Ascorhynchus is described. The male of Pallenopsis (Bathypallenopsis) scoparia is described for the first time. A number of new records of bathypelagic Colossendeis allow interpretation of the status of C. gardineri, recorded here for only the third time. The bathypelagic habit of pycnogonids is discussed.

Sound bites, science and the Brent Spar: Environmental considerations relevant to the deep-sea disposal option

One of the happier consequences of Greenpeace's high profile campaign in stopping the sinking of the Brent Spar in the North Atlantic off north-western Scotland has been a better awareness of the deep ocean. At the start of the campaign, when the redundant structure was occupied by Greenpeace activists, there was ignorance in the media and amongst political commentators just where in the sea Shell UK had obtained permission to sink the structure. It was well into the campaign that press statements and Greenpeace sound bites stopped confusing the North Sea with the North Atlantic Ocean. The Greenpeace campaign focused public and scientific attention on the environmental and ecological issues related to deep-sea dumping. Even then, in the face of all the emotion generated by Greenpeace, many scientists were willing to give Shell the benefit of the doubt in spite of a lack of hard information. It was largely as a reaction to this background that we, with deep-sea biologist colleagues at the Institute of Oceanographic Sciences at Wormley, wrote letters to British newspapers pointing out that on the basis of what we knew of deep-sea ecology, a one-off deep-sea disposal of Brent Spar might not be the environmental catastrophe suggested by Greenpeace. An editorial in Nature (29 June 1995), immediately after the sinking was called off, suggested the change in plan was irrational and that it is to shallow seas that activist and public concern should be directed rather than the deep ocean. Other scientific comment accepted that (even if the case for deep-sea disposal might have been finely balanced with regard to other options) the implications regarding disposal of other platforms could not be ignored. However, Shell have said that the Brent Spar is unique in requiring this form of disposal and that most offshore installations will be totally removed and scrapped onshore. Copies of the Brent Spar abandonment best practicable environmental option and impact hypothesis reports were sent to us by Shell in July, after the sinking was called off, as well as by Greenpeace, who wrote individually to a broad section of marine scientists. This allowed us to see the detailed scientific assessment leading to the choice of the deep-sea disposal option.

Forty years of land-locked oceanography; the Institute of Oceanographic Sciences at Wormley, 1953–1995

In the summer of 1995 the Institute of Oceanographic Sciences moves from Wormley, where it has been for 40 years, to newly built premises at Southampton forming, with the University's Departments of Geology and Oceanography, the Southampton Oceanography Centre. This article reviews the Institute's history, major achievements, and aspirations.

Polar continental margins: Studies off East Greenland

The passive continental margin off east Greenland has been shaped by tectonic and sedimentary processes, and typical physiographic patterns have evolved over the past few million years under the influence of the late Cenozoic Northern Hemisphere glaciations. The Greenland ice shield has been particularly affected.GLORIA (Geological Long Range Inclined Asdic), the Institute of Oceanographic Sciences' (IOS) long‐range, side‐scan sonar, was used on a 1992 RV Livonia cruise to map large‐scale changes in sedimentary patterns along the east Greenland continental margin. The overall objective of this research program was to determine the variety of large‐scale seafloor processes to improve our understanding of the interaction between ice sheets, current regimes, and sedimentary processes. In cooperation with IOS and the RV Livonia, a high‐quality set of seafloor data has been produced. GLORIA'S first survey of east Greenland's continental margin covered several 1000‐ × 50‐km‐wide swaths (Figure 1) and yielded an impressive sidescan sonar image of the complete Greenland Basin and margin (about 250,000 km2). A mosaic of the data was made at a scale of 1:375,000. The base map was prepared with a polar stereographic projection having a standard parallel of 71°.

Global undersea research program examined

Geological understanding of age and horizontal variations of oceanic plates from mid‐ocean ridges to deep‐sea trenches, including interactive phenomena between continental and oceanic plates, especially in areas transecting trenches, arcs, and back‐arc basins was addressed at the 1992 Workshop on the Global Undersea Research Program, held at the Japan Marine Science and Technology Center (JAMSTEC), Tokyo, Japan, from September 2 to 4, 1992. The meeting was held following a proposal at the 1991 International Symposium to commemorate the 20th anniversary of JAMSTEC to hold a workshop on undersea research to discuss the utilization of undersea devices such as manned submersibles and remotely operated vehicles (ROVs).The goals of the September meeting were to improve research cooperation among organizations using manned submersibles or ROVs; to support more effective research programs by avoiding unnecessary research duplication; and to discuss new technologies, scientific needs, and functional requirements for hardware being developed for manned submersibles and ROVs. About twenty‐five scientists participated from the National Science Foundation; National Oceanic and Atmospheric Administration; Woods Hole Oceanographic Institution (WHOI); University of Hawaii; Institut Français de Recherche pour l'Exploitation des Mers (IFREMER), France; Ocean Research Institute, University of Tokyo; Earthquake Research Institute, University of Tokyo; Geological Survey of Japan; Institute of Oceanographic Sciences (IOS), Deacon Laboratory, United Kingdom; and JAMSTEC.

Multisensor, deep‐towed instrument explores ocean floor

Acoustic imagery of the ocean floor has seen great advances in recent years with the development of wide‐multibeam, swath‐mapping sonar and high‐resolution, side‐scan sonar [Tyce, 1986]. TOBI, a deep‐towed vehicle built by the Institute of Oceanographic Sciences, Wormley, U.K., is the newest of these instruments to be developed. It is towed at depths of up to 6000 m at an altitude of 400 m above the bottom. It carries a variety of sensors, including a 30‐ to 32‐kHz dual‐sided side‐scan sonar (6‐km swath), a 7.5‐kHz subbottom seismic profiler, a triaxial luxgate magnetometer, a temperature sensor, a photo‐transmissometer, and vehicle status sensors (pitch, roll, heading, speed, and hydrostatic pressure).

Quaternary Sedimentary Processes on the Northwestern African Continental Margin--An Integrated Study Using Side-Scan Sonar, High-Resolution Profiling, and Core Data

Side-scan sonar data, cores, and high-resolution profiles have been used to produce an integrated model of sedimentation for the continental margin west of the Canary Islands. Long-range side-scan sonar (GLORIA) data and a grid of 3.5-kHz profiles, covering some 200,000 km{sup 2} allow a regional appraisal of sedimentation. More detailed studies of selected areas have been undertaken using a new 30 kHz deep-towed side-scan sonar (TOBI) developed by the U.K. Institute of Oceanographic Sciences. Sediment cores have been used both to calibrate acoustic facies identified on sonographs and for detailed stratigraphic studies. The most recent significant sedimentation event in the area is to Saharan Sediment Slide, which carried material from the upper continental slope off West Africa to the edge of the Madeira Abyssal Plain, a distance of some 1000 km. The authors data shows the downslope evolution of the debris flow. Near the Canaries, it is a 20-m-thick deposit rafting coherent blocks of more than 1 km diameter; side-scan records show a strong flow-parallel fabric on a scale of tens of meters. On the lower slope, the debris flow thins to a few meters, the flow fabric disappears, and the rafted blocks decrease to meters in diameter. Side-scan datamore » from the lower slope show that the Saharan Slide buries an older landscape of turbidity current channels, typically 1 km wide and 50 m deep. Evidence from the Madeiran Abyssal Plain indicates a history of large but infrequent turbidity currents, the emplacement of which is related to the effects of sea level changes on the northwest African margin.« less

A new electronic system for the rectangular midwater trawl (RMT)

This paper describes a modified modern version of the original rectangular midwater trawl (RMT) manufactured by the Institute of Oceanographic Sciences (IOS). The shipboard acoustic transducer and the underwater RMT-monitor were replaced by an electronic interface box was while the data transfer, realized by a single-conductor cable. Using frequency shift keying (FSK) signal transmission, a PC-controlled system onboard handles data acquisition and control as well as real time monitoring of the haul. The volume of water filtered by the net is calculated based on the online readings of a net-angle sensor. The new RMT-system was successfully used in the Antarctic during the European Polarstern Study (EPOS) from October 1988 to March 1989. Fifty-seven tows to a maximum depth of 1000 m in open waters and in ice covered areas were performed.

GLORIA: the second decade

Report of a meeting jointly sponsored by the Marine Studies Group of the Geological Society and the Challenger Society for Marine Science held at Burlington House on 1 February 1989. T. J. G. Francis, the convenor, opened the meeting by briefly summarizing the development of the GLORIA (Geological Long Range Inclined Asdic) long range sidescan sonar at the Institute of Oceanographic Sciences since the mid-nineteen sixties. GLORIA has established itself in the nineteen eighties as the ideal tool for surveying Exclusive Economic Zones (EEZs). GLORIA surveys were carried out for 241 days in 1988 from two different ships, 140 of which were spent surveying the United States EEZ with the U.S. Geological Survey. By the end of 1988, some 13 million km 2 of ocean floor has been surveyed, which is about 4% of the ocean deeper than 200m. The scale of USGS activity with GLORIA was equivalent to all UK deep Ocean geology and geophysics. R. C. Searle (IOSDL, Wormley) spoke on the contribution of GLORIA to understanding mid-oceanic ridge tectonics. After reviewing a wide range of observations from the Atlantic, Pacific and Indian Oceans, he reported the results of the recent survey of the whole of the Easter Microplate camed out from RRS Charles Darwin last November. This revealed for the first time the complex plate boundaries, spreading fabric and associated propagating rifts and transform faults of the whole of this unusual feature. D. Twichell (USGS, Woods Hole) spoke about the integration of digital bathymetry (SEABEAM) and sidescan (GLORIA) data with particular reference to the Gulf of Mexico. Gridding of the two data sets was done on the USGS Mini Image Processing System (MIPS). Since the sidescan backscatter

Vertical profiles of pelagic communities in the vicinity of the Azores Front and their implications to deep ocean ecology

Three early wintertime and five early summertime stations were occupied in the vicinity of the Azores Front to the south-west of the islands. At each station the surface 1100–1400m of the water column were systematically sampled both by day and by night, using the Institute of Oceanographic Sciences' RMTI+8M system. The biological sampling was set in the context of an extensive study of the physical oceanography of the frontal region. It included one station in the core of an eddy which was seen to spawn from a meander during the course of the physical observations. The biological communities on either side of the front were almost indistinguishable in terms of their specific composition. However, there were substantial differences in the sizes of the standing-crops, the vertical distributions of the major taxonomic groups and the ranges of the diel vertical migrations being carried out by these groups. The waters on both sides of the front were oligotrophic. However, both phytoplankton standing-crop, as indicated by chlorophyll concentrations, and measures of productivity suggested that the water to the north (Eastern Atlantic Water), which was slightly cooler and with a shallower and steeper nutricline, was a little more productive than the water to the south (Western Atlantic Water). Associated with this trend in phytoplankton crop and productivity were quite sharp declines in the standing-crops of both plankton and micronekton across the front, moving from EAW to WAW. There was no evidence of enhanced productivity within the front itself, but there was an increase in the micronektonic standing-crop. Between the stations, there were consistent trends in the ratios of the standing-crops of plankton and micronekton, which were sampled simultaneously. By day, the planktonic biomasses exceeded the micronektonic biomasses by up to an order of magnitude in the wind-mixed layer. The ratios declined with depth, approaching unity at 200m during the wintertime, but remaining quite high to depths of 800m during the summer. At night, the ratios tended to be lower as a result of diel vertical migration, but except in one or two of the deepest samples the planktonic biomass always exceeded that of the micronekton. The total biomass profiles were very similar in shape between the stations, although there were quite large differences in the depths of the quartiles. There were substantial differences between the day and the night profiles. These could be attributed mostly to the effects of diel vertical migrations, but must also have included unquantifiable effects as a result of variations in net avoidance. The subdivision of the catches into the major taxonomic groups showed that the degree of avoidance varied substantially between them; euphausiids were the most effective daytime avoiders, but decapod crustaceans and fish showed a suprisingly small tendency to avoid. The ranges and the numbers of each group undertaking vertical migrations varied markedly between the stations, and these differences were expressed in the biomass estimates. Attempts have been made to quantify the movement of biomass in and out of the surface 200m and 500m resulting from these migrations. There were substantial changes in migratory behaviour across the front, even though there were no detectable changes in the light profiles. The data also imply that the micronektonic migrants play an important role in the active transport of organic substances down from the euphotic zone to mesopelagic depths (>500m), either in their gut contents or directly as a result of predation at depth. In addition, migrating plankton seem likely to be important in redistributing nutrients about the nutricline in these oligotrophic regions where the water column stability limits physical vertical mixing processes. Preliminary estimates suggest that their influence may be sufficiently large to alter the ratio between “new” and “old” production.

Remote Sensing in Marine Environment--Acquiring, Processing, and Interpreting GLORIA Sidescan Sonar Images of Deep Sea Floor: ABSTRACT

The US Geological Survey's remote sensing instrument for regional imaging of the deep sea floor (> 400 m water depth) is the GLORIA (Geologic Long-Range Inclined Asdic) sidescan sonar system, designed and operated by the British Institute of Oceanographic Sciences. A 30-sec sweep rate provides for a swath width of approximately 45 km, depending on water depth. The return signal is digitally recorded as 8 bit data to provide a cross-range pixel dimension of 50 m. Postcruise image processing is carried out by using USGS software. Processing includes precision water-column removal, geometric and radiometric corrections, and contrast enhancement. Mosaicking includes map grid fitting, concatenation, and tone matching. Seismic reflection profiles, acquired along track during the survey, are image correlative and provide a subsurface dimension unique to marine remote sensing. Generally GLORIA image interpretation is based on brightness variations which are largely a function of (1) surface roughness at a scale of approximately 1 m and (2) slope changes of more than about 4/degrees/ over distances of at least 50 m. Broader, low-frequency changes in slope that cannot be detected from the Gloria data can be determined from seismic profiles. Digital files of bathymetry derived from echo-sounder data can be mergedmore » with GLORIA image data to create relief models of the sea floor for geomorphic interpretation of regional slope effects.« less

The tides of the Atlantic Ocean, 60° N to 30° S

This paper is a sequel to Cartwright, Edden, Spencer & Vassie (1980) (henceforth C.E.S.V.), which concentrated on the tides of a small portion of the North Atlantic between the MidAtlantic Ridge and the west European shelf. In both works we have aimed to discover what can be learnt of the spatial dynamic properties of the ocean tides from direct measurements in the open sea, with a minimum of prejudice from the artefacts of computer models. An essential background has been a development over roughly 15 years (1970—1985) of the instrumental technique of recording pressure variations on the ocean floor for long periods, together with their associated acoustic recall systems and calibrating devices. This instrumental development has been led principally by one of the authors (R. S.) with the help of colleagues at the Bidston and Wormley laboratories of the Institute of Oceanographic Sciences (IOS). The sea-going activity described in C.E.S.V. had seemed adventurous, because tidal variations offshore had not been measured before in that part of the Atlantic Ocean, but when compared with computer-generated tidal maps of the world ocean the distances reached appear small on the scale of the principal wavelengths. Similar measurements in the Atlantic by other authorities were concentrated in a narrow band within a few hundred kilometres of the east coasts of Canada and the U.S.A. (Cartwrightet al. 1979). With the sanction of the IOS we decided to bridge the gap between east and west Atlantic by a few supplementary lines of pressure recordings between the existing sets. Some pressure records from the equatorial zone taken later as part of a climate research programme (Cartwright al. 1987) extended the network further to the south. We shall be concerned here with the analysis of these new data sets and with the interpretation of the whole available set of tidal constants from the Atlantic Ocean including islands and coasts.

New xenophyophores (Protista) from the bathyal and abyssal north-east Atlantic Ocean

Eight species of xenophyophores, seven of them new, are described from epibenthic sledge material collected in the north-east Atlantic by the Institute of Oceanographic Sciences. A new genus is established for two of the new species, Homogammina lamina and H. maculosa. The other five new species are Galatheammina discoveryi, G. microconcha, Psammina delicata, P. fusca and P. sabulosa. The eighth species is Reticulammina labyrinthica Tendal, 1972, first described from the south-west Pacific. The material considerably expands knowledge of north-east Atlantic xenophyophores, emphasizes the dominance in this area of the order Psamminida, and suggests a considerable degree of endemism. All specimens are highly fragmented and it is therefore difficult to correlate the species described from the samples with those appearing in simultaneously taken bottom photographs.

The genus Bathysiphon (Protista, Foraminiferida) in the north-east Atlantic: a neotype for B. filiformis G.O. & M. Sars, 1872 and the description of a new species

Bathysiphon filiformis G.O. & M. Sars in G.O. Sars, 1872, the type-species of the large, tubular, agglutinated foraminiferal genus Bathysiphon, has been confused in the literature with other members of the genus. In order to stabilize this species, a neotype is selected from material collected in the type-area (Hardangerfjord, Norway) and housed in the British Museum (Natural History). Bathysiphon filiformis is redescribed on the basis of this material and also from specimens collected in the bathyal north-east Atlantic by the Institute of Oceanographic Sciences (IOS). A new species, B. hystrix sp. nov., which is closely allied to B. filiformis, is described from specimens in IOS collections.