By the death of George Tatton Atkinson at Lowestoft on the 30th November, 1974, in his ninetieth year, the last link is broken with those famous pioneering days when the M.B.A. undertook, on behalf of the Government, the first official English fishery investigations by opening a special laboratory at Lowestoft in 1902 under the direction of Dr Walter Garstang. It is fitting that the life of George Atkinson should be recorded in our pages. Born in 1885 he came from a great sea-faring family and combined his love of the sea with an intense interest in marine natural history. As soon as he left school in 1904 he joined Garstang as an assistant working particularly on the biology of the plaice.

If newly released spores of red algae are placed in a suspension of Indian ink in sea water, a clear halo of mucilaginous material will be seen. A similar mucilage cover is also a well-known feature with certain phytoplankton organisms, in which cells of spiny appearance (e.g. freshwater desmids) assume a spherical form in Indian ink when the mucilage cover is also observed (Lund, 1959). The attachment of red algal spores is a process in which mucilage clearly plays some part (Suto, 1950; Nakazawa, 1958; Matsumoto, 1959; Boney, 1966; Linskens, 1966; Moorjani & Jones, 1972; Charters, Neushul & Coon, 1972; Chamberlain & Evans, 1973). Studies on the sinking rate and dispersal of red algal spores have been described (Suto, 1950; Boney, 1965, 1966; Coon, Neushul & Charters, 1972). There appears to be little information on the sizes of the spore mucilage sheaths, and on their likely significance in the planktonic phase of the spore's existence immediately after release. The present work gives the results of an investigation of the spore mucilage of fourteen species of red algae.

Twenty-six species of marine planktonic algae, belonging to 8 taxonomic divisions, were tested tinder axenic-culture conditions for their capacity to grow, under cool-white light, on nitrate, nitrite, ammonium, urea, glycine, D-glucosamine or hypoxanthine as sole nitrogen source. The culture medium was composed of Mediterranean oligotrophic sea water enriched with phosphate, silicate, trace-metal ions and vitamins, and buffered at pH 7.5–80. Each nitrogen compound was tested at a fixed concentration of 500 μg-at. N per litre.

In a recent publication in this Journal I presented a set of seven equations effecting to describe from a single set of constants any chemostat steady state of the flagellate Monochrysis lutheri in terms of phosphorus and vitamin B12 without prejudice as to which was rate limiting, given only the input concentrations of the two nutrients and the dilution rate of the chemostat (Droop, 1974, equations 23–29). There was nothing inherent in this description to prevent its application to transient situations, and I felt that at least it should apply to the transitional phase of a batch culture. The aim of this paper, which is a continuation of the previous one, is to find out whether this is so and whether in fact the model can be adapted to describe the complete history of a batch culture, because if it can its value to predictive models for phytoplankton would be greatly enhanced.

It is now well established that natural phytoplankton populations may liberate a substantial proportion of the carbon fixed in photosynthesis directly into the external medium in the form of dissolved organic matter. Glycollate may be an important component of this extracellular organic fraction, both in culture (Hellebust, 1965) and in the natural environment (Watt, 1966). Nevertheless, it has been difficult to investigate the role of glycollate in the environment because of the lack of a convenient and reliable method for determining its concentration in natural waters. Shah & Fogg (1973) and Shah & Wright (1974), however, have developed a procedure for glycollate analysis in sea water, based on adsorption on to alumina and subsequent elution for determination by the Calkins colorimetric technique, which is both sensitive and not too laborious for routine analyses. Fogg (1966) suggested that glycollate excreted by phytoplankton acts as an extracellular reserve which may be utilized for survival under conditions unfavourable for photosynthesis. Wright & Hobbie (1965) showed that some fresh water bacteria take up glycollate at rates of the same order of magnitude as for acetate and glucose. Glycollate would therefore appear to be of importance in the energy flow between different trophic levels. In order to evaluate these hypotheses it seems important to determine the concentrations and turnover rates of glycollate occurring in natural waters.

There are two critical stages in the life history of Laminaria hyperborea (Gunn.) Fosl. The first is the attachment of the zoospores (meiospores) to suitable rock surfaces and the second is the successful fusion of gametes. The second clearly partly depends on the first which is in turn affected by the efficiency of zoospore production by the sporophyte and the time of year that this takes place. Because of lack of information on these aspects the present study of reproduction in the sporophyte was undertaken.

In marine organisms the fresh-weight concentrations of the trace metals zinc and iron are 102–105 times the concentrations in sea water. Study of the transfer of these metals along marine food chains is of interest because of the possibility of their being pollutants of the marine environment. Also65Zn and 65Fe are released to the marine environment and have been found, in many instances, to be the predominant radionuclides in food chains leading to man (Lowman, Palumbo & South, 1957; Lowman, 1960; Osterberg, Pearcy & Curl, 1964; Preston, 1967). The transfer of these metals along marine food chains is thus of interest also in the context of human radiation exposure.

The published records of the occurrence of the Devonshire Cup Coral Caryophyllia smithii Stokes and Broderip in Scottish waters are widely scattered throughout the literature. Rees (1962, 1966) listed several of these and suggested that the paucity of records was a reflexion of the comparatively little systematic collecting that had been done on the Scottish coasts and on the continental shelf.

The purpose of the present paper is to collate and review the published records of the distribution of C. smithii and to present new data derived from extensive investigations carried out by the Institute of Oceanographic Sciences, Wormley, as part of a study of shelly faunas and sediments on the continental shelf west and north of Scotland. Additional records obtained from several other sources are also included.

Hensen (,1887) drew attention to the possibility of using a pump for quantitative sampling of surface plankton and, since then, a hose-pump method has been widely used for such sampling at desired depths by Juday (1916), Lohmann (1898,1901), and Thorson (1946). A comparative study by Gibbons & Fraser (1937) suggested that such a pump had outstanding advantages over the vertical net, in quantitative work. However, Korringa (1941), working on oyster larvae, suggested that some plankton animals may be able to escape by swimming against the currents which approach the mouth of the suction hose. Brook & Woodward (1956) noticed an apparently rheotactic response shown by plankton organisms in evading water currents.

Previous (workers who have examined the gut contents of members of the genus Parathemisto, and who have kept and fed specimens in laboratory conditions, have concluded that they are chiefly carnivorous in habit, feeding largely on zooplankton, and to a lesser extent on phytoplankton (Conover, 1960; Baker, 1963; Kane, 1967).

The gut of P. gaudichaudi has been found to contain almost intact copepods, especially Calanus and occasionally Temora (Bigelow, 1926 – Gulf of Maine); young specimens of Euphausia superba (Hardy & Gunther, 1935 – Antarctic); and copepods (Nemoto & Yoo, 1970). Siegfried (1965 – west coast of S. Africa) found P. gaudichaudi to be a rather indiscriminate feeder, its gut contents reflecting the composition of the plankton.

Elasmobranch fishes cannot at present be aged by scale or otolith readings as can certain teleosts. Consequently comparatively little is known about their age or rate of growth, particularly in the case of larger sharks. Alternative methods of age determination within this group have utilized tagging data (Bonham et al., 1949; Holden, 1972); size frequencies (Olsen, 1954; Aasen, 1966); the spine of Squalus sp. (Kaganovskaia, 1933; Holden & Meadows, 1962); tooth-replacement rates (Moss, 1967, 1972) and vertebral rings. These rings on the vertebral centra, resulting from variations in calcification, have also been used in the age determination of teleosts. In the scombroids there is often considerable variation in results even between authors working on the same species, mainly due to difficulty in interpreting the rings and deciding whether they are true year marks (Aikawa & Katô, 1938; Partlo, 1955; Otsu & Uchida, 1959; Hui-chong, Nose & Hiyama, 1965).

The importance of the blood in crustacean metabolism was first raised by Johnston, Davies & Elder in 1971. Until then the conventional view had been that the crab hepatopancreas had a role similar to that of the vertebrate liver (Vonk, 1960), the blood presumably acting as a carrier of soluble sugars. It has recently been shown, however, that blood tissue holds almost four times the amount of polysaccharide than the hepatopancreas and that glucose is actively incorporated into glycogen in the blood (Johnston & Davies, 1972). Polysaccharides were located in deposits in the haematocytes (Johnston, Elder & Davies, 1973). Many previous studies have shown that the main plasma sugar, glucose, varies widely in concentration and appears very sensitive to the animals physio-logical state (see Hohnke & Scheer, 1970). It would seem, therefore, that glucose metabolism in crabs may be readily modified and that by looking at the effect of a physiological stress (starvation and feeding) on the blood/hepatopancreas system one might get some information on the dynamic relationship between these two organs. Previous work (P. L. Lutz, unpublished) had shown that in Carcinus maenas plasma glucose could fall to negligible values on prolonged starvation.

As recent studies have shown that in Crustacea the haemolymph plays an important role in carbohydrate metabolism (Johnston & Davies, 1972, Williams & Lutz, 1975) it is clear that a proper understanding of this phenomenon depends on an accurate knowledge of the variety of cell types found. However, an examination of the literature revealed a wide divergence of opinion in the recognition of various kinds, their relationships and their composition, with, for example, the same authors reaching quite different conclusions from similar evidence (Johnston, Davies & Elder, 1971, Johnson, Elder & Davies, 1973) (Table 1). This suggested that the subject required further examination. As both the type and number of cells may vary according to the condition of the animal (Sniesko & Taylor, 1947), it was decided to look at the blood of fed and starved specimens.

In previous papers we have shown that high temperature and low food levels result in a decline in the body condition of mussels, Mytilus edulis, which have been kept in the laboratory (Bayne & Thompson, 1970; Gabbott & Bayne, 1973). In spite of the loss of body reserves, M. edulis is able to continue gonad development at an increased rate, when the temperature is above ambient (Gabbott & Bayne, 1973; Bayne, 1975). Although gametogenesis appears to be normal under these conditions, there is evidence that stress in the adult affects subsequent larval development in M. edulis (Bayne, 1972) and in the oyster, Ostrea edulis (Helm, Holland & Stephenson, 1973). In mussels, stress resulted in an increase in abnormal embryonic development during cleavage, gastrulation and development to the first shelled larval stage (Bayne, 1972). In oysters the viability of the larvae, assessed in terms of growth rate and percentage yield of spat, was less in larvae from adults kept at low ration than in larvae from adults kept at high ration. Irrespective of the feeding regime, the viability of the larvae fell as the length of the conditioning period increased, and this was related to a decline in the body condition of the adult oysters. The growth of the larvae in the 96 h period following liberation was significantly correlated with the lipid level in the newly released larvae (Helm, Holland & Stephenson, 1973).

While working on taxonomic problems in the family Dotoidae and comparing the Mediterranean and Atlantic species (Schmekel & Kress, in the Press), it became apparent that very little embryological information was available for this group, other than that published by Alder & Hancock (1845–55), Pelseneer (1911), Miller (1958, Ph.D. Thesis, University of Liverpool) and Thompson (1967).

In the course of studies on the changes in egg-capsule volume in different nudibranch species (Kress, 1971, 1972) a fresh attempt has been made to obtain some comparative data on egg and capsule sizes and on the course and rate of embryonic development in the three species of Doto most commonly found in the Plymouth area, namely D. coronata (Gmelin, 1791), D. pinnatifida (Montagu, 1804) and D. fragilis (Forbes, 1838).

In an earlier study of the biochemical composition of barnacle cement, Walker (1972) found that the cements of two sessile barnacles, Balanus hameri and B. crenatus contained small amounts of lipid (< 1% of total dry wt.) and carbohydrate (♎ 2% of total dry wt.) but were mainly composed of protein ( > 85 % ° of total dry wt.). Lindner & Dooley (1973) similarly found that a large proportion of B. crenatus cement was protein (80%), but Cook (1970) found only 70% protein, lipid (27.4%) being the other major constituent. There is therefore general agreement that barnacle cement is mainly a proteinaceous secretion, but controversy still exists over the amount of lipid present.

Recent improvements in gear and techniques have permitted much more detailed studies to be made of vertical distribution patterns of pelagic oceanic organisms (Vinogradov, 1970; Foxton, 1972). One such development is the RMT 1 + 8 opening-closing net system for sampling plankton and micronekton (Baker, Clarke & Harris, 1973) which can be acoustically monitored in situ for fishing depth, water temperature, flow and net operations. This sampler has been used to study the midwater communities in the N.E. Atlantic over the last 6 years during cruises by RRS ‘Discovery’. It has been successfully operated to depths of 4000 m.

The quantitative zoogeography of pelagic zooplankton is a subject very much in its infancy. This is due to a number of causes; firstly, the taxonomy of a large number of animal groups has not been finalized and new species are still being regularly discovered. Secondly, many samples, especially from the earlier expeditions, were obtained from broad depth ranges and without accurate depth measurements or the use of opening-closing nets. This latter problem has been overcome by modern sampling devices (e.g. Baker, Clarke & Harris, 1973).

Underlying the thinking of a lot of previous workers has been the hypothesis that the water masses of the various oceans (usually delineated by means of temperature-salinity relationships (Sverdrup, Johnson & Fleming, 1942)) support a distinct fauna. This point of view has been summarized by Johnson & Brinton (1963), Banse (1964) and Beklemishev (1966, 1971). Examples of studies in which the relationship of species distributions to water masses have been studied are Pickford (1946; the cephalopod Vampyroteuthis infernalis), David (1958,1963; chaetognaths), Bieri (1959; Pacific chaetognaths), Brinton (1962; Pacific euphausiids), McGowan (i960; the worm Poebius meseres) and Haffner (1952; the fish genus Chauliodus). In the last case it was suggested that the oxygen content of the water was also an important factor.