ALBERT

Notes: Abstract The south-western quarter of the North Sea (between the Wash and the River Tyne) has been investigated for the presence of dinoflagellates. Extensive net surveys were carried out in March, May and June 1971 and a number of other collections were made in the area. North of Flamborough Head, the spring bloom of diatoms was succeeded by a considerable growth of dinoflagellates, of which Dinophysis norvegica was the most abundant organism. Maximum counts of over 28 million dinoflagellates per m3 were recorded. Distribution charts are given for the most common species. A total of 61 species was found during the course of the survey.

Notes: Abstract Sperm and eggs of sand dollars, Melitta quinquiesperforata (Leske), were subjected to two petroleum oils, and effects determined. The oils chosen were Kuwait crude and No. 2 fuel oil, supplied by the American Petroleum Institute. Water-soluble extracts (WSF) from oil-sea water mixes were prepared and the major aromatic components in the WSF of the fuel oil were identified. WSF of No. 2 fuel oil depressed respiration, mobility of sperm, interfered with fertilization and cleavage, and retarded larval development. The effects were detectable at dilutions of 4% and less (about 0.6 ppm of WSF). Kuwait crude was much less toxic. There was no effect on water permeability of the egg membrane. Results are compared with similar studies on other marine organisms.

Notes: Abstract The transfer of chlorinated hydrocarbons (CHC) in a laboratory simulation of a three trophic level marine food chain was studied. The food chain consisted of the algal flagellate Dunaliella sp., the rotifer Brachionus plicatilis, and the larva of the Northern anchovy Engraulis mordax. CHC were introduced into the seawater at concentrations representative of near-shore conditions off southern California without the use of dispersing agents. Each trophic level appeared to be in a steady-state at the time of first sampling, 5 days after inoculation. Apparent partition coefficients were calculated for each trophic level. The CHC contamination in the diet of the rotifers and anchovy larvae was also calculated. Unfed anchovy larvae accumulated the same amount of CHC as fed larvae and the final concentration appeared to be dependent on the CHC concentration in the seawater. The data in this report suggest that CHC accumulation is not a food-chain phenomenon but rather the result of direct partitioning of the compounds between the seawater and the test organisms.

Notes: Abstract In most areas of the north-eastern Atlantic Ocean, diatoms have declined drastically in abundance in the last decade. Additionally, in areas to the north of 59°N Ceratium species and an index of total phytoplankton have also declined. South of 59°N the phytoplankton index has increased, diatoms have declined and Ceratium species have remained at a constant level of abundance. A possible explanation of the increase in the phytoplankton index at a time when the diatoms were declinig south of 59°N is the development of unidentified phytoplankton organisms such as microflagellates. As many of the variables influencing phytoplankton standing crop are governed in turn by the prevailing weather, the phytoplankton changes may well be a consequence of the general deterioration, since 1940, of North Atlantic weather. Changes in phytoplankton which may be attributed to an amelioration of climate since 1971 are evident as yet only in the southern North Sea.

Notes: Abstract A variety of detrital foods derived from marsh plants were fed to the copepods Eurycemora affinis and Scottolana canadensis. The copepods did not survive well or produce eggs when feeding on detritus with smaller amounts of microbiota, but did well when a rich and abundant microbiota was present. Ciliated protozoans appear to be particularly important in the transfer of detrital energy to copepods.

Notes: Abstract Meiofauna was sampled using SCUBA along 4 transects from 5 to 30 m depth in Algoa Bay, South Africa. Substrates were well-sorted medium to fine sands with traces of sewage pollution in some areas. Meiofauna numbers recorded in the upper 10 cm of sediment were 55 to 584 10 cm-2, but total numbers, including deeper-living animals, were 680 to 2090 10 cm-2 at 6 stations. Longer cores showed meiofauna to be abundant down to at least 35 cm, and samples of interstitial water taken from this depth in the sediment were 7% saturated with oxygen. This is the first detailed record of meiofauna penetration into sub-littoral sand and stresses the need for long cores for quantitative work. Nematode numbers were found to be significantly related to nitrogen in the sand while interstitial harpacticoid numbers were related to median particle diameters, which determine pore space. Effects of sewage were slight and only one station showed notable enrichment, increased meiofaunal numbers and extreme dominance by nematodes.

Notes: Abstract Oxygen evolution and uptake by whole thalli of the large marine alga Laminaria longicruris de la Pylaie were measured for 24 h, once every 2 weeks for a year, using large chambers to incubate the plants on the sea bed. Diel rates of photosynthesis and respiration were calculated from these measurements and continuous light measurements were used to extrapolate the data between observation dates. The resulting estimates were combined with measurements of growth and carbon content to give an annual carbon budget for a typical mature plant. Annual net assimilation was 6.8 mgC per cm2 of frond surface (71 cal cm-2). Approximately 45% of this appeared in the production of new frond tissue, and a further 12% was accounted for by storage of carbon in mature frond tissue. About 8% was needed for stipe growth, and the remaining 35% was assumed to be lost as dissolved organic carbon. Diel net photosynthetic rates reached a maximum in June and July and were negative only in November, indicating an ability to produce a photosynthetic surplus throughout winter. In early winter the plants drew on stored reserves to supplement photosynthesis in providing carbon for growth, but from January onwards photosynthesis provided more than enough carbon for growth.

Notes: Abstract Combined effects of lead, salinity and temperature on the embryonic development of the mussel Mytilus galloprovincialis Lmk. were studied under laboratory conditions. The basic experimental design was a 4x6 factorial experiment using 4 lead concentrations (100, 250, 500 and 1000 ppb Pb2+) and 6 salinity levels (from 25 to 37.5‰ with 2.5‰ intervals). These factorial designs were carried out at three constant temperatures (150, 17.50 and 20°C). The statistical analysis indicated that salinity changes have more effect on the embryonic development than temperature. Optimal development was observed at 34.8‰ and 15.6°C, which is in accordance with observations in the field. The effect of lead was mininal in optimal salinity and temperature conditions. The deleterious effect of lead on the embryonic development was especially conspicuous at 20°C. Since in nature spawning occurs at temperatures inferior to 20°C, lead will probably not drastically decrease the potential recruitment of mussel spat in the littoral populations of the northern Adriatic Sea, where the salinity of the water is relatively stable. Under experimental conditions, lead caused a delay or inhibition of the embryonic development with the occurrence of a large number of abnormal larvae.

Notes: Abstract Sorites orbiculus (Ehrenberg), S. orbitolitoides (Hofker) and Amphisorus hemprichii (Ehrenberg) harbor dinophyceans similar to, but not identical with, Symbiodinium microadriaticum. The symbionts, which bear shortened flagella, are concentrated beneath the well-lit, lateral test wall. They are able to change position actively within the lacunary system of the host cell.

Notes: Abstract Photosynthesis in whole plants of the intertidal alga Ascophyllum nodosum ecad scorpiodes was evaluated by measuring 14C-uptake under a variety of light intensities and approximately monthly intervals during a 15 month study. Photosynthetic rates were determined in terms of dry weight, pigment content and uptake into ethanolsoluble and insoluble fractions. The specimens, naturally acclimated to in situ light intensities and temperatures, exhibited photosynthetic responses to light intensity which differed with time of year. Maximum photosynthetic potential occurred during the spring months and minimum potential occurred during late summer and winter months. Variations in photosynthetic potential were closely related to seasonal changes in field biomass. Both photosynthetic potential and biomass were inversely related to growth patterns of the salt-marsh phanerogam Spartina alternilora.

Notes: Abstract Photosynthesis in whole plants of the salt-marsh algae Fucus vesiculosus and Ulva lactuca was evaluated by 14C-uptake under a variety of light intensities at approximately mately monthly intervals during a 15-month study. Photosynthetic capacity in both species was closely related to seasonal irradiation patterns and changes in field biomass. Maximum photosynthesis occurred in the spring and summer months. Photosynthesis on a dry weight basis was higher in U. lactuca, while photosynthesis on a chlorophyll a basis was equal in both species. Photosynthetic capacity was inversely related to pigment content. Maximum chlorophyll a concentrations occurred during the winter. Frond profile studies in F. vesiculosus indicated that apices always exhibited greatest photosynthetic capacity. Uptake of 14C into ethanol-soluble and insoluble fractions was different in each species. F. vesiculosus showed greater activity in the ethanol-soluble fraction while U. lactuca exhibited greater activity in ethanol-insoluble fractions.

Notes: Abstract The addition of two commerical fertilizers, one 5% NH4NO3, 10% P2O5, 10% K2O, and the other 10% NH4NO3, 10% P2O5, 10% K2O, ahd a dramatic effect on the growth of Zostera marina in the Chesapeake Bay. There was a significant increase in the length, biomass and total number of turions of fertilized plots compared with controls during a 2 to 3 month period. Data from this short-term field experiment suggest that Z. marina beds in the Chesapeake Bay are nutrient-limited, that the grwoth form of Z. marina may be related to the sediment nutrient supply, and that Z. marina may competitively exclude Ruppia maritima by light-shading.

Notes: Abstract Concentrations of zinc and cadmium in muscle tissue or whole Pacific hake, Merluccius productus (Ayres), increase with increasing total wet weight, especially for smaller fish. These trends appear to be related to the euphausiid diet of hake. Except for the isolated population in Puget Sound, no relationship between zinc or cadmium concentration and collection site is apparent.

Notes: Abstract It is evident from previous studies that heavy metal levels are changed in tumorbearing organisms relative to nontumor-bearing organisms, particularly in apparently normal liver tissue. This study considered the possible role of metallothioneins in binding excess Cd, Cu or Zn in the liver of tumor-bearing flounders (Parophrys vetulus). Cadmium and zinc were not increased significantly on the metallothionein peak, but were increased 3.3- and 2.4-fold, respectively, on the high molecular weight protein peak. In addition, the Cd:Zn ratio was increased by 40% on the high molecular weight protein peak. Results are discussed in terms of competition of Cd and Zn for Zn-requiring enzymes involved in nucleic acid metabolism. Possible reasons for excess Cd occurring on the high molecular weight protein peak rather than on the metallothionein peak are discussed. Copper levels did not change.

Notes: Abstract During the end of the phytoplankton spring bloom, about 100 water samples were taken at 23 stations in the Baltic Sea. The samples were analyzed for particulate Cu, Fe, Zn, Cd, and Pb by atomic absorption as well as for chlorophyll and seston. Further subsamples were counted with an inverted microscope, and phytoplankton carbon content was calculated. The hydrographical-biological state of the Baltic Sea during spring is described. Two different water masses could be differentiated and these were separated by the halocline. The concentrations of particulate metals are in accordance with those published by other authors. No significant differences could be calculated between mean values of particulate metal concentrations in the two water bodies. Correlations between particulate metal concentrations and chlorophyll, seston, phytoplankton carbon and cell-count were calculated for both photic layer and deeper waters. Significant correlations were found only in the photic layer. The importance of standing crop for metal accumulation in seston is discussed.

Notes: Abstract Induction of benzo (a) pyrene monooxygenase (BPMO) activity occurred in Blennius pavo, a species with a restricted territorial range, in response to exposure to a Diesel 2 oil. A response delay of 14 days was found at a concentration of 170 ppb and of 3 days when the water was saturated with Diesel 2 oil. When induced fish were transferred to clean water, elevated BPMO activity was maintained at a high level for at least a month. A benthic protochordate, Microcosmos sulcatus, showed no increase in BPMO activity when exposed to these concentrations even after 30 days of exposure. Field observations revealed a great variation in the BPMO activity from B. pavo caught at different sites. Fish from contaminated sites had significantly elevated levels of BPMO activity. Sardine schools caught at different sites had different, low levels of BPMO activities. However, specimens from the same school had closely similar levels of enzyme activity. An oil pollution incident (New Year 1977 oil spill in Northern Adriatic Sea) caused an increase in the BPMO activity in the livers of Blenniideae, reaching a peak on the 23rd day (representing an 8.5-fold increase in the background level), followed by a decrease in activity until a new background level, 3 times that of the original background level, was reached on the 45th day. This new background level is constant (through May-5 months after the incident). Measurement of BPMO activity in the livers of nonmigrant fish could serve as a useful biochemical parameter for monitoring and evaluation of acute or long-term oil pollution at a given site.

Notes: Abstract The specific activity of 55Fe in plankton increased from below detectable limits at 20°N to a maximum of 130 nCi/g Fe at 20°S and then decreased to 5 nCi/g Fe at 50°S. Along an east-west track near 15°S a peak of 90 nCi/g Fe occurred at 135°W. It is suggested that this maximum is the result of fallout from French nuclear tests at Mururoa Atoll (22°S; 139°W). The increase in 55Fe at high latitudes observed in previous studies in the North Atlantic Ocean and North Pacific Ocean did not occur in the South Pacific Ocean which supports the suggestion that belts of high tropospheric fallout accounted for the increase in the Northern oceans.

Notes: Abstract Hard shell clams, Mercenaria mercenaria, from the chronically polluted environment of the Providence River, USA, were transferred to a clean laboratory system located in lower Narragansett Bay, Rhode Island. The hydrocarbon contents of these transplanted clams were monitored for 120 days after transfer. After this period only slight depuration had occurred. A 41.9 μg g wet weight-1 average initial hydrocarbon burden decreased to 29.3 μg g-1, a decrease that became statistically significant (P〈0.1) only after 120 days. At most, only 30% of the clams' hydrocarbons were lost. These findings indicate that the duration of the exposure period and the chemical nature of the source hydrocarbons are both instrumental in determining the persistence of these compounds in filter-feeding bivalves. Chronically accumulated petroleum hydrocarbons are strongly retained by the organisms and are only very slowly depurated.

Notes: Abstract The digestive tract of Sabellaria alveolata (L.) is partitioned into 4 main regions: oesophagus, gizzard, intestine and rectum. Histoenzymologic study of the repartition of the protease activities along the digestive tract has shown that the proteases are secreted in the anterior intestine, where numerous serous gland cells are present. These cells display many histochemical and cytological characteristics similar to those of the gland cells previously described in digestive organs of other polychaetes. The role of the other regions of the digestive tract is discussed.

Notes: Abstract Surface tissue of the reef coral Pocillopora capitata contained approximately 34% lipid on a dry weight basis. Of this, 75% was storage lipid (wax ester and triglyceride) and 25% structural (phospholipid, galactolipid, etc.). Based on chlorophyll a: lipid ratios of intact coral and isolated zooxanthellae, it was determined that over 90% of the storage lipid resided in the host tissue. One half of the structural lipids was found in the host and the other in the symbiotic algae. Gentle fractionation of coral tissue indicated that zooxanthellae possessed less than 14% of the total coral protein. Coral tips and isolated zooxanthellae were incubated with sodium acetate-1-14C in light and dark to obtain lipogenic rates and proportions of fatty acids and lipid classes synthesized. The rate of lipid synthesis from acetate-1-14C by intact coral was stimulated three-fold in the light (1200 lux), which indicated that the majority of coral lipogenesis occurred in the zooxanthellae. Intact coral triglycerides contained ca. 68% of the 14C-activity and wax esters ca. 21%. Zooxanthellae isolated by the Water Pik technique synthesized negligible amounts of wax ester, which implied that wax ester synthesis was a property of the animal tissue. Isolated zooxanthellae and intact coral synthesized identical triglyceride fatty acids from acetate-1-14C. This study provides evidence for a carbon cycle between host and symbiont whereby the zooxanthellae take up host-derived carbon (probably in the form of acetate), synthesize fatty acids using their photosynthetically derived energy, and return the lipid to the host where it appears as wax ester and triglyceride.

Notes: Abstract Growth and mortality rates of the gastropod Cerithium nodulosum Bruguière were investigated by repetitive mark-and-recapture censuses for the inner and middle reef flat subpopulations of Pago Bay, Guam, from February to October 1975. Overall population density was about 2 individuals per 100 m2 in October. Juveniles (28 to 75 mm shell length) grew at mean rates of from 2.3 to 4.6 mm per month, with great (average coefficient of variation, CV: 32% of the mean) individual variations within the cohorts. The adult stage, which ceases growing in length after forming characteristic shell apertures, was reached within 3 years. Individual adult sizes varied markedly within each subpopulation; the mean shell length was 76.3 mm (standard deviation, SD=6.2, N=129) for the inner and middle reef flat subpopulation and 84.3 mm (SD=6.6; N=127) for the outer reef flat subpopulation. The difference in mean adult shell length between the two subpopulations was highly significant (0.01 level). Mortality rates were estimated from the slopes of regression lines fitted to the catch curves. Assuming tag loss of 10%, crude mortality rates were 15 to 20% per month for the population of C. nodulosum.

Notes: Abstract Synchronous measurements were made of the routine rate of oxygen consumption and the clearance rate of Phaeodactylum tricornutum at different exposure temperatures by specimens of the suspension-feeding gastropod Crepidula fornicata which had been acclimated to temperatures between 10° and 25°C. The results show that the cost of activity (μl O2 consumed h-1/ml seawater cleared h-1) increases dramatically in individuals exposed to short-term increases of temperature up to 30°C, especially in limpets acclimated to 10°C. The process of thermal acclimation, however, results in two compensatory adjustments in energy expenditure and uptake which profoundly affect the energetics of water transport. Firstly, the routine oxygen consumption shows lateral translation of the rate-temperature curve which results in the maintenance of a relatively uniform energy expenditure despite an increase in acclimation temperature from 10° to 25°C. Secondly, because of the form of the rate-temperature curve for filtration by C. fornicata, lateral translation in response to warm acclimation results in an increase in the maximal clearance rate. Lateral translation of the rate-temperature curves for feeding rates and for oxygen consumption in response to thermal acclimation may thus be linked to maintain a balance between energy gain and expenditure. In this way, the greatly increased cost of activity which would occur with increase of temperature in the absence of acclimation is evaded. The minimal maintenance energy requirement, and hence the greatest scope for growth and reproduction, is then adjusted to coincide with temperatures prevailing in the environment.

Notes: Abstract Assimilation rates of 15N-labelled ammonium, urea, and nitrate by plankton in the upper euphotic zone were measured in 2 summer, 2 winter, and 1 spring cruise in the central North Pacific Ocean. Average rates of ammonium plus urea assimilation could not be determined precisely, but were estimated to be 7 to 25 μg-at. N m-3 day-1. Indirect evidence suggested that non-photosynthetic microorganisms contributed to these rates. Nitrate assimilation was negligible in the upper waters considered in this report (above the chlorophyll maximum and the nutricline). Potential, nitrate-saturated rates were in the range 1 to 8 μg-at. N m-3 day-1. Seasonal comparison showed lowest rates of both carbon and nitrogen assimilation rates per chlorophyll a in winter.

Notes: Abstract Preening (cleaning, grooming) of the antennules and other cephalothoracic appendages by the third maxillipeds was observed in several species of shrimp. Distribution and ultrastructure of serrate grooming setae on the third maxillipeds, which scrape the antennules, was studied with light and scanning electron microscopy. The motor patterns of antennular cleaning were similar for all species. Antennular preening was the most frequent grooming behavior observed, but the duration of other grooming behaviors was greater. Tidepool shrimps (Heptacarpus pictus) experimentally prevented from grooming the antennules by ablation suffered fouling of the olfactory hairs of the antennules with their subsequent breakage and loss; antennules of controls remained clean and undamaged. Antennular preening, a frequent and widespread behavior of caridean shrimps and other decapod crustaceans, is suggested as having high adaptive value in keeping sensory sites free of epizoic and sedimentary fouling which might render them inoperative.

Notes: Abstract The relative abundance of chaetodontid and pomacentrid fishes in 8 habitats, ranging in depth from 0.5 to 17 m, was determined by visual counting of free-swimming fish in the field. Habitat widths and overlaps were determined using weighting factors, developed by Colwell and Futuyma (1971), which account for the different degree of uniqueness of each habitat. The average habitat widths and the average habitat overlaps were greater for the chaetodontids than the pomacentrids. This was due, in part, to the greater use of habitat structure by the pomacentrids, and it is hypothesized that this is because they are the more vulnerable to predation. The juveniles and adults reached peak abundance in different habitats for at least some of the species, and this may further reduce the habitat-overlap values for adults of some pairs of species. It is clear, however, that the ability of the species in these families to coexist is largely due to factors operating within habitats rather than to a large degree of habitat specialization.

Notes: Abstract The known distribution of Calanus helgolandicus in the North Atlantic Drift is difficult to explain in the absence of a reproductively active population inhabiting continental waters off eastern North America. New evidece indicates that this population, overlooked in the past, does in fact exist. The species has been found in a study of zooplankton samples from a number of MARMAP (Marine Resource Monitoring, Assessment, and Prediction Program) cruises surveying ichthyoplankton between Cape Hatteras and the New York Bight. Sexual activity in these stocks of C. helgolandicus was indicated by the ripeness of ovaries, the frequency of males, the presence of sperm in the females' seminal receptacles and the appearance of a female bearing a Calanus spermatophore. The new records provide a likely origin for the presence of the species in the vicinity of the Labrador Grand Banks as well as further east in the North Atlantic Drift. C. finmarchicus, similarly sexually active, was found to be sympatric with C. helgolandicus in the MARMAP collections which were taken from a region contiguous with the southernmost, known distribution, of C. glacialis. The distribution of integumental organs (i.e., pore signature patterns) was examined in the three species to determine whether they would be taxonomically useful. Strikingly different patterns were found on the female urosome. Pore signature differences between the polar species C. glacialis and the temperate C. helgolandicus proved to be as pronounced as those between the boreal C. finmarchicus and its two neighboring species. The successively overlapping ranges and the distinctive differences in pore signature patterns suggest that divergence from the generic pattern of integumental organ distribution has been a product of selection against hybridizing among the three species. If this is in fact the case, the reproductive range of C. helgolandicus has overlapped with those of C. finmarchicus and C. glacialis for appreciable periods in the history of the three species.

Notes: Abstract The life history of the red alga Rhodophysema elegans (J. Ag.) Dixon (Peyssoneliaceae: Cryptonemiales), which was commonly found at 4 localities on the south coast of England, has been investigated in laboratory culture. Tetraspores (the only reproductive organs observed) which were derived from field material germinated to repeat the parental tetrasporangiate phase. Sexual reproductive organs were not observed. It is suggested that the probable cause of this “direct” type of life history is the occurrence of apomeiosis in the sporangial primordium.

Notes: Abstract The present study attempts to determine the factors which induce spores in the genus Peyssonnelia to undergo two different forms of embryogeny. Carpospores and tetraspores of P. squamaria (Gmelin, 1768) Decaisne, 1841 were cultivated, and two types of development noted: the “Dumontia type”, typical of prevalently saxicolous thalli, and the “Naccaria type”, observed in plants growing as emi-endophytes. This is the first time that this phenomenon has been observed in the Peyssonneliaceae.

Notes: Abstract East Pacific swimming crabs are poorly known ecologically. We trawled samples along 4 estuarine-continental shelf transects to provide information on the population structure and species composition of portunids along environmental stress gradients. Portunids comprised almost 99% of the benthic crabs. Callinectes toxotes dominates the freshest estuarine areas, but is replaced by C. arcuatus in estuary mouth and shallow-shelf samples. Deeper shelf samples are dominated by Euphylax robustus and Portunus sper. Great numbers of E. dovii, a pelagic species, were taken on the shelf; their size distribution implies intraspecific competition. Evidence is given that differences in salinity tolerance account for differential landward limits, but competition, predation by fishes, increased fouling and decreased available food exclude eurytopic species from physicochemically equable shelf waters.

Notes: Abstract Euphylax dovii Stimpson (Brachyura: Portunidae: Podophthalminae), a tropical Eastern Pacific swimming crab, has distinctive morphological adaptations for pelagic existence. Crabs in collections from the open ocean had a sex ratio approximating 1:1, with no crabs bearing eggs. Samples from the continental shelf of Colombia contained thousands of females, mostly ovigerous, but no males. Egg attachment has posed a major problem in the evolution of decapod crustaceans, and the two genera of portunid crabs thus far observed cannot attach eggs unless females can bury partly in soft sediments. This suggests that mated E. dovii females must migrate into shallow shelf waters to encounter sediments necessary for spawning. The high energetic cost of swimming while carrying eggs and the presence of abundant food for larvae are factors favoring residence of females in shelf waters until hatching is complete.

Notes: Abstract The exchanges of phosphorus between the Flax Pond, a tidal Spartina alterniflora marsh on the north shore of Long Island (USA) and Long Island Sound were measured over 18 months. Phosphate was exported from the marsh from May through December and imported during the remainder of the year. Organic phosphorus appears to be accumulated in all seasons, but the yearly phosphorus budget of the marsh is approximately balanced despite the accumulation of about 6 mm of sediment annually.

Notes: Abstract The populations of Beggiatoa species were quantified in the sediments of a brackish fjord (Limfjorden, Denmark) over a period of 1 year. The bacterial distribution was compared to the physical structure of the sediment, the redox profile, the concentration and production rate of H2S, and the rate of O2 consumption. The bacteria are absent in fine and in medium-grained sand, but in muds which are aggregated in faecal pellets very high population densities are found throughout the year with average biomasses of 5 to 20 g m-2. The bacteria seldom form coatings on the surface, but are distributed within the upper few centimeters of oxic sediment. They receive H2S partly from the lower anoxic layers and partly from reduced microniches scattered in the oxidized zone. Estimates of their metabolic rates indicate that Beggiatoa spp. may play a significant role in the sulfur and carbon cycles of the investigated sediments.

Notes: Abstract The heritability of oyster (Crassostrea virginica) larval growth rate was estimated to be in the range of 0.25 to 0.50 and a significant part of this genetic variation is of the additive type. Larval growth rate and spat growth rate were found to be highly correlated. These results suggest that a selection program for faster growing larvae and spat would be successful.

Notes: Abstract Lanternfishes (Myctophidae) often bear not only small primary photophores, but also larger regions of luminous tissue, described as glands or patches. These have a superficial appearance very different to that of the primary photophores, but examination of the tissues of some 14 genera has shown that all the luminous organs are composed of fundamentally similar stacks of photogenic lamellae. The degree of organisation of the lamellae varies in different genera, but the caudal organs and the other larger luminous regions contain much more of this photogenic tissue than do the primary photophores. Some observations on the operation of both primary and caudal organs are described.

Notes: Abstract By using two different radioactive mercury isotopes, detailed information was obtained on the uptake and simultaneous release of mercury by Dunaliella tertiolecta. Hg-203 was added to a well-aged culture, which 2 days later was separated from the medium, washed and cultivated again in a fresh medium containing Hg-197. It was found that an exchange of mercury takes place between the cells and the medium. An increase in the concentration of volatile mercury occurs simultaneously with the maximum concentration of chlorophyll a. Comparing the culture solutions with the blanks, the dissolved mercury shows similar volatility. This leads to the assumption that the main part of the dissolved mercury in the culture solutions is in the inorganic state.

Notes: Abstract The vertical structure, composition and productivity of a plankton community was studied in the Japan Sea in June, 1972 during a period of thermocline formation; the parameters measured were: phytoplankton production and biomass; number, biomass, and production of planktonic bacteria; biomass of phagotrophic flagellates, ciliates and remaining microzooplankton. The concentration of micro- and mesozooplankton attained a basic maximum in a layer near the upper part of the thermocline. The biomass and calculated production of the heterotrophic part of the community exceeded considerably the amount of primary production. The heterotrophic phase of the seasonal succession of a plankton community in a temperate sea is described, when heterotrophic metabolism and production predominate. Heterotrophs at this stage use mostly energy from organic matter accumulated during the previous spring phytoplankton “bloom”.

Notes: Abstract Pigments of the meso- and bathypelagic chaetognaths Sagitta macrocephala and Eukrohnia fowleri were studied by chromatographic analysis. Supplementary histological studies were also performed. Fat-soluble properties and absorption spectra of the chaetognath pigments indicated that all pigments were carotenoid, independent of chaetognath species or habitat. The major carotenoid in chaetognaths was very soluble in nonpolar solvents such as carotenes, although its absorption spectrum formed a single broad peak at around 460 nm. The characteristics of the carotenoids in the chaetognaths were different from those of the pigments in the plankton which formed their diet. It is therefore inferred that carotenoids in chaetognaths are not formed by the deposition of food pigments in the intestinal tissue, but are synthesized by the chaetognaths themselves.

Notes: Abstract Critical thermal maxima (CTM) were determined for winter flounder (Pseudopleuronectes americanus, Walbaum) and scup (Stenotomus chrysops, L.), acclimated to ambient water temperature or constant increments above ambient. The acclimation regimes simulated a natural environment by tracking the temperature fluctuations in Point Judith Pond, a small Rhode Island estuary. An elevation in CTM from 30.2° to 35.6°C was observed for scup as the mean acclimation temperature increased from 14.8° to 22.2°C. CTM for flounder increased from 26.4° to 32.4°C over an acclimation range of 4.2° to 23.0°C. The use of CTM studies for predicting the effects of heated effluents is discussed.

Notes: Abstract I quantified the effects of parasitism by the isopod Probopyrus pandalicola on energy flow through the host Palaemonetes pugio by comparing secondary production, metabolism, ingestion, and egestion by unparasitized laboratory shrimp populations to the same parameters for parasitized groups during 10 months. The effects of parasitism on host growth and metabolism vary from month to month. Temperature, season, host age, sex, and reproductive condition affect energetics for host-parasite systems. Probopyrus pandalicola has little effect on host assimilation efficiency. However, tissue growth efficiences during most study months were higher for control shrimp than parasitized shrimp. These differences between groups were of lesser magnitude when parasite production was considered in the calculations. Trophic level energy intake efficiency for parasites was of the order of 6 to 10% throughout much of the study—the highest values were calculated during the parasites' reproductive months. Through parasitic castration, P. pandalicola significantly affects host energetics. Significantly, parasite reproduction was often of the same magnitude as reproduction by unparasitized hosts, although parasite biomass accounts for only about 4% of the total host-parasite system biomass.

Notes: Abstract Taphromysis bowmani, previously considered to be an estuarine species, is shown to reproduce and complete its life cycle in fresh water. Both sexes and all life history stages were collected from March to June 1975, in the Wakulla River, Florida (USA), where chlorinity, alkalinity and total hardness were relatively high. Development was synchronous within a brood but not between broods. Brood size was positively correlated with female size, and ripe ovaries of brooding females suggest that at least 2 broods per female are possible. Breeding appears to occur throughout the year. The relatively high ion content, especially chloride, in the Wakulla River may account for the presence of T. bowmani. Other estuarine mysids reported from fresh water are noted.

Notes: Abstract Resting schools of juvenile grunts (less than 12 cm length), composed primarily of Haemulon flavolineatum and H. plumieri, were studied from 1972 to 1976 on a series of patch reefs surrounded by seagrass beds on the northeast coast of St. Croix, U.S. Virgin Islands. Juvenile grunts form large inactive multispecies schools in reef areas by day. Repeated censuses over several years reveal that certain parts of the reef, particularly those with large formations of the corals Porites porites and Acropora palmata, are traditional schooling areas. When the fishes reach a size of about 15 cm, the H. plumieri form homotypic schools which roam the patch reefs but are no longer associated with particular formations of coral. In contrast, larger H. flavolineatum are uncommon on the patch reefs and they may move offshore to deeper water. The schools of juvenile grunts migrate some distance away (often 100 to 300 m) into seagrass-covered areas to feed on invertebrates at dusk each day. The routes which are followed into the seagrass beds are precise and persist over years. At dawn the grunts return to the reef on the same routes. Mass marking and release experiments show that juvenile grunts will move over long distances (approximately 3 km) to reach a home reef.

Notes: Abstract Crassostrea virginica Gmelin were subjected to simulated tidal fluctuations of salinity, and the subsequent effects on osmotic and ionic composition of the pericardial fluid, body water and valve movements were investigated. Ambient salinity fluctuation patterns of 20-10-20‰, 15-10-15‰ and 10-5-10‰ were simulated during 24.8-h periods. An additional 10-5-10‰ S experiment was performed using a dilution water approximating the ionic composition of Mississippi River water with regard to Mg++, Ca++ and SO 4 = , instead of deionized water. Finally the effects of a 2-week diurnal fluctuation pattern between 20 and 10‰ S were investigated with respect to pericardial fluid composition. Pericardial fluid osmolality, concentrations of Cl-, Na+, Mg++, K+, Ca++ and ninhydrin-positive substances (NPS) were analyzed periodically throughout all experiments. Pericardial fluid osmolality was slightly hyperosmotic as ambient water salinity decreased during a cycle, and then became slightly hyposmotic as ambient salinity increased. In the 2-week experiment, pericardial fluid osmolality tracked ambient seawater closely through Day 5, but became more intermediate between high and low seawater values as the experiment progressed. Similar patterns during fluctuations of salinity were observed for Na+, Cl-, Mg++ and Ca++. Pericardial fluid K+ levels did not track ambient seawater as closely as did other ions. The ionic composition of dilution water had little effect on the osmotic or ionic response of the oyster's pericardial fluid. Pericardial fluid NPS level varied inversely with salinity during the 20-10-20‰ cycle. During the longterm fluctuation experiment, NPS values gradually decreased over the 2-week period compared to constant salinity control values. Percent body water also varied inversely with ambient salinity. Solute movement accounted for most of the change in pericardial fluid osmolality during the simulated cycles with water movement responsible for 1 to 11%. Water movement contributed more to the change of pericardial fluid osmolality during the decreasing salinity phase than the increasing phase of a given cycle. During 20-10-20‰ S cycles, oyster valves remained open 56% of the time (n=23). In contrast, when salinity was abruptly changed from 20 to 10‰ within 5 min, valve closure occurred in 4.8±0.3 min (n=20). Valves did not reopen for 19.3±1.2 h (n=15).

Notes: Abstract The relationships between netplankton and nanoplankton assimilation numbers, temperature, and major nutrient concentrations were studied and evaluated in the context of seasonal patterns in the biomass of these phytoplankton size fractions. Netplankton and nanoplankton blooms typically occur during late winter (2° to 8°C) and summer (18° to 24°C), respectively. Variations in nanoplankton and netplankton assimilation numbers were not statistically related to the development or collapse of specific blooms based on weekly sampling, but assimilation numbers were higher during the bloom periods than during transition periods of rapid temperature change (8° to 18°C). Differences in the assimilation numbers between size fractions could account for the dominance of the nanoplankton fraction during the summer bloom period but not for the dominance of netplankton during the winter bloom period. Nanoplankton and netplankton assimilation numbers were exponential functions of temperature between 8° and 24°C and 8° and 20°C, respectively. Below 8°C the assimilation numbers of both fractions were higher than expected on the basis of temperature. Above 20°C netplankton assimilation numbers declined with temperature. Netplankton and nanoplankton assimilation numbers were occasionally correlated with dissolved inorganic nitrogen concentrations from less than 1.0 to more than 15 μg-at l-1. Under these conditions, nanoplankton growth rates (calculated from assimilation number and carbon:chlorophyll) were higher and increased more rapidly with dissolved inorganic nitrogen than netplankton growth rates.

Notes: Abstract We compared the effect of habitat and water depth on the light-harvesting pigment content for Ascophyllum nodosum and Fucus vesiculosus at two near-shore stations in Long Island Sound (USA). Excised pieces of seaweeds were attached at depth intervals to a vertically buoyed line, and left in situ for 7 days. For comparison, fronds were collected from sun and shade habitats in the littoral zone. The three major antenna (light-harvesting) pigments increased in concentration with depth or shade. Chlorophyll c to a ratios remained stable at about 0.2. Fucoxanthin to chlorophyll a ratios decreased by 20 to 30% with depth or shade. Although pigment composition for the two rockweed species was equivalent, the maximum photosynthetic performance of F. vesiculosus exceeded that of A. nodosum by a factor of 2, while the compensation depths for 4 m-adapted A. nodosum and F. vesiculosus under natural limiting light conditions were equivalent. Plants held at 4 m had higher photosynthetic rates compared with plants held at 0 m, no matter the depth of measurement. Indirect evidence indicates that the enhanced photosynthesis of 4 m-adapted plants is due not only to higher concentrations of antenna pigments but to other physiological factors as well. We conclude that the clearly delineated vertical distribution of these two canopy species, the F. vesiculosus zone over the A. nodosum zone, is not determined by light quantity or quality, but by biotic factors as evidenced by the experiments of Menge which are cited herein.

Notes: Abstract Along the California coast there are three intertidal species of the genus Gibbonsia (G. elegans, G. metzi, G. montereyensis). These species have distinct but overlapping distributions. Collections were made seasonally from three areas. Each collection was divided into two groups — a critical thermal maximum and minimum were determined for one group and the other group was tested after a 3 week acclimation period. The three species showed genetically different adaptation abilities and these were correlated with species differences in latitudinal distributions. The species that experiences the widest seasonal temperature range proved capable of anticipatory adjustment to temperature while the two experiencing small seasonal changes showed only reactive adjustments. the species with the widest distribution showed the greatest ability to adapt to temperature extremes. After 1 week acclimation all three species demonstrated different mechanisms for heat and cold adaptation.

Notes: Abstract Freshly collected pieces of the hermatypic coral Acropora cf. scandens containing dinoflagellate endosymbionts (presumably Gymnodinium microadriaticum) were allowed to assimilated 14C from H14CO 3 - in the light and in the dark. Time-dependent carbon uptake resulted in intense 14C-labelling of ethanol-soluble as well as of insoluble assimilates. About forty 14C-labelled assimilates have been identified. Polymeric (ethanol-insoluble) compounds achieve about 30% of total radiocarbon incorporation after 60 min incubation. Kinetics of 14C-labelling of single assimilates are analyzed. Percentages of typical photosynthates in the soluble fraction undergo characteristic time-dependent changes. Lipids proved to be the main accumulation products of carbon assimilation by incorporating more than 50% of 14C after 60 min photosynthesis. The data indicate that low-molecular weight photosynthates such as 14C-glycerol and 14C-glucose are rapidly converted to constituents of the polymeric fraction(s) of the coral. Besides peptides, polysaccharides, and lipophilic substances, considerable amounts of 14C are confined to skeletal CaCO3 of the coral. The results are discussed with respect to trophic and metabolic interrelationships between the autotrophic dinoflagellates and the A. cf. scandens tissues.

Notes: Abstract An investigation was undertaken to determine the distribution and activity of the heterotrophic microplankton associated with particles from a Georgia salt marshestuarine ecosystem to the western edge of the Sargasso Sea. Heterotrophic activity was determined by the uptake of 14C-glucose. More than 80% of the activity was associated with detritus greater than 3 μm in creek, river and coastal (within 4 km of shore) waters. In the Gulf Stream, approximately 80% of the heterotrophic activity was in the fraction less than 3 μm. In the estuary, total heterotrophic activity fluctuated with the tides; the greatest activity occurred near low ebb tide at all locations. The lowest activity was measured at slack low and high tides. In creek water most of the heterotrophic activity was associated with particles between 14 and 180 μm, whereas in coastal waters (less than 4 km from shore) most of the activity was in the fraction greater than 180 μm.

Notes: Abstract Caprellid amphipods feed by browsing, filter-feeding, predation, scavenging, and scraping. Food acquisition is related to the presence or absence of plumose setae on the second antenna; those species with such setae obtain a significant amount of their diet from filtering and scraping periphyton while those species without such setae usually rely on predation. Two primary predators and 8 primary filter-feeders and scrapers were investigated. Substrates inhabited by the predators did not overlap, but some filter-feeders were found together. Feeding overlap has been decreased among filter-feeders that occur together, as they either feed on different sized particles or they filter at different heights from the substrate. Species filtering the same sized particles at the same heights that were found together utilized alternate feeding mechanisms, e.g. browsing on algal filaments.

Notes: Abstract Three marine diatoms, Skeletonema costatum, Chaetoceros debilis, and Thalassiosira gravida were grown under no limitation and ammonium or silicate limitation or starvation. Changes in cell morphology were documented with photomicrographs of ammonium and silicate-limited and non-limited cells, and correlated with observed changes in chemical composition. Cultures grown under silicate starvation or limitation showed an increase in particulate carbon, nitrogen and phosporus and chlorophyll a per unit cell volume compared to non-limited cells; particulate silica per cell volume decreased. Si-starved cells were different from Si-limited cells in that the former contained more particulate carbon and silica per cell volume. The most sensitive indicator of silicate limitation or starvation was the ratio C:Si, being 3 to 5 times higher than the values for non-limited cells. The ratios Si:chlorophyll a and S:P were lower and N:Si was higher than non-limited cells by a factor of 2 to 3. The other ratios, C:N, C:P, C:chlorophyll a, N:chlorophyll a, P:chlorophyll a and N:P were considered not to be sensitive indicators of silicate limitation or starvation. Chlorophyll a, and particulate nitrogen per unit cell volume decreased under ammonium limitation and starvation. NH4-starved cells contained more chlorophyll a, carbon, nitrogen, silica, and phosphorus per cell volume than NH4-limited cells. N:Si was the most sensitive ratio to ammonium limitation or starvation, being 2 to 3 times lower than non-limited cells. Si:chlorophyll a, P:chlorophyll a and N:P were less sensitive, while the ratios C:N, C:chlorophyll a, N:chlorophyll a, C:Si, C:P and Si:P were the least sensitive. Limited cells had less of the limiting nutrient per unit cell volume than starved cells and more of the non-limiting nutrients (i.e., silica and phosphorus for NH4-limited cells). This suggests that nutrient-limited cells rather than nutrient-starved cells should be used along with non-limited cells to measure the full range of potential change in cellular chemical composition for one species under nutrient limitation.

Notes: Abstract The kinetic response of ammonium- or silicate-limited and ammonium- or silicatestarved populations of Chaetoceros debilis, Skeletonema costatum, and Thalassiosira gravida was determined by a single addition of the limiting nutrient to a steady-state culture and subsequent monitoring of the nutrient disappearance of the limiting and non-limiting nutrients at frequent time intervals. The kinetic response of nonlimited (nutrient) populations of these three species was also determined. Three distinct modes of the uptake of the limiting nutrient were observed for ammonium-or silicate-limited populations of these three species, surge uptake (V s ), internally (cellular) controlled uptake (V i ), and externally (ambient limiting nutrient concentration) controlled uptake (V e ). Non-limited populations did not exhibit the three distinct segments of uptake, V s , V i and V e . Estimates of the maximal uptake rate (V max) and the Michaelis constant (K s ) were obtained from nutrient-limited populations during the V e segment of the uptake curve. Pooled values of V e for the three ammonium-limited populations yielded V max and K s estimates of 0.16 h-1 and 0.5 μg-at NH4−N l-1. Kinetic data derived from the V e segment of the uptake curve for silicate-limited populations yielded different values of V max and K s for each of the three species. In a number of parameters that were measured, T. gravida was clearly different from C. debilis and S. costatum and its recovery from nutrient starvation was the slowest. Recovery of all species from silicate limitation or starvation was slower than from ammonium limitation or starvation. Ammonium-starved populations maintained a maximal uptake rate at a substrate concentration an order of magnitude lower (≈0.1 μg-at NH4−N l-1) than that observed for NH4-limited populations (≈1.0 μg-at NH4−N l-1). Adaptation to the severity of the nutrient limitation occurred as changes in the magnitude of cellular characteristics, such as short-term uptake potential (V s ) and affinity for the substrate (K s ). The consequence of these results are discussed in terms of another possible mechanism to explain changes in species composition and succession in nutrient-depleted environments.

Notes: Abstract Using our previous experience in benthos sampling, we have developed a new, automatic, submarine suction apparatus for qualitative sampling. The sampler is easy to handle and has been in use for a year. Suction is effected by means of compressed air, from SCUBA diving bottles, and is regulated from the surface. Water inlets in the form of 5 small tubes are used to counterbalance the suction effect. About 15 kg lead ballast the sampler.

Notes: Abstract An apparatus is described for incubating large marine algae in light and dark chambers on the sea floor, while providing vigorous circulation of water prefiltered to remove phytoplankton. Successful use of the equiment in over 500 h of incubations of Laminaria longicruris has shown that earlier methods in which strips of tissue are incubated in bottles greatly overestimates dark respiration rates and increases experimental error. The effect of these findings on long-term productivity estimates is discussed.

Notes: Abstract Male Emerita asiatica Milne Edwards are smaller than females. The secondary sexual characters of males and females are described in detail. Applying the method of Wenner (1972), sex ratio is calculated. The overlap in size range between males and females is too wide to suggest sex reversal. An analysis of secondary sexual characters in post-larval juveniles during megalopa settlement corroborates the view that males and females develop separately from the megalopa. The males acquire their sexual maturity soon after metamorphosis from the megalopa stage, whereas the females attain their sexual maturity only after considerable body growth. the males continue to grow to attain a maximum carapace length of 11 mm; they do not show any tendency towards changing their sex. This is evidenced by the fact that the weight increase of the gonadal apparatus is directly related to the increase in the male carapace length (CL) and body weight. On the other hand, retention of larval characters such as short eye stalk, toothless chelae of the fifth leg (in males up to 5 mm CL), together with the very small size suggest that the males are neotenic. Only males up to 5 mm CL were found to take part in mating. During mating, as many as 5 tiny males deposit their spermatophores in the pleopodal region of one female. This type of mating assures effective transfer of spermatophores in the turbulent environment inhabited. Spermatophores are pedunculate and embedded in a gelatinous matrix to form a long ribbon. There are two types of spermatophores in the ribbon, and they differ in detail from those of other anomuran species. The spermatozoa are rod-like, with a club-shaped acrosomal head. Five spines originate from the junction between head and body. The mode of sperm release from the spermatophores is described; oviducal secretion may be responsible for opening the spermatophore.

Notes: Abstract The species richness of sessile organisms on settlement panels on a coral reef was measured by the slope of a regression of loge number of species against loge area of sample. At a well illuminated site where panels were colonised by algae, the species richness of algae was 19% smaller on surfaces grazed by fishes than on protected surfaces. At a second site in a cave, the species richness of animals on grazed surfaces was 20% greater than on protected surfaces. These results are discussed in the light of differences between the sites. The contrasting effects of predation at the two sites are probably the result of more selective predation at the cave site than at the other site.

Notes: Abstract In the first settlement stages on immersed glass slides, the degree of colonization by an organism is determined by the duration as well as the season of immersion. Therefore, in the first period of settlement no ecological succession is obvious, but different ecological groups are favoured according to the prevailing environmental conditions. The development of these groups is regulated by well-defined physico-chemical conditions. First settlement stages would therefore play only a minor role in the subsequent development of a colony and attainment of its and final steady state.

Notes: Abstract Benthic, free-living marine nematodes from two stations, one subtidal, one intertidal, in the North Inlet Estuary, South Carolina, USA, have been characterized by measurement of adenosine triphosphate (ATP), carbon, caloric content, and ash-free dry weight. Two methods of extracting the organisms from the sediment were used. Resulting carbon to ATP ratios and population density data from ongoing North Inlet meiofauna studies show that the nematodes account for 0.11 to 6.33 μg ATP per g dry weight of sediment, varying seasonally. The percentage of nematode ATP/g sediment is higher in the winter and lowest in the summer, and accounts for 68% to over 90% of the total sediment ATP. The findings of this study indicate that meiofauna, particularly nematodes, can no longer be overlooked as a separate entity in attempts to partition benthic systems.

Notes: Abstract Nereid polychaetes (Nereis vexillosa and Platynereis bicanaliculata) attach pieces of drift algae to their tube surfaces. The presence of permanent algal cover increases the predictability of the food supply for at least the herbivores (including the nereids) and the deposit feeders, and modulates the temperature and salinity stresses of the marine intertidal soft-bottom environment. However, it may affect the access of organisms to the oxygenated water layers above the sediment surface. This is true for polychaetes that live head downwards in vertical tubes. It is suggested that the attachment behavior of the nereid polychaetes increases the ability of the plant to colonize habitats both temporally and spatially.

Notes: Abstract A mosaic patchwork of the barnacle Balanus balanoides L., the mussel Mytilus edulis L., and the alga Fucus vesiculosus L. was found in the transitional region between the mid and high intertidal zones on a rocky headland on Mount Desert Island, Maine, USA. The development of the mosaic was observed by following recruitment and survival of B. balanoides in denuded patches located at the same tidal level along a 60 m stretch of shore. Barnacle recruitment was least under canopies of F. vesiculosus and greatest in open areas kept moist at low tide by surf. Barnacle survival after settlement was least under the F. vesiculosus canopy due to the whiplash effect of the algal fronds in the surf and greatest in open areas free from competition from mussels. In open areas, early mortality was correlated with settlement density. In areas of dense settlement (60 spat cm-2) up to 90% mortality resulted within 5 months from crowding associated with growth. In older individuals crowding produced hummocks of elongated, weakly attached barnacles which were more prone to removal by surf than uncrowded barnacles. Mussels exerted competitive dominance over barnacles for space and the presence of mussel beds prevented further barnacle recruitment. Mussels suffered extensive mortality during winter storms when surf removed dense mats of weakly attached mussels. The patchy distribution of mussels and barnacles results from irregular rock substrata producing numerous environmental patches with respect to wave exposure and drainage at low tide, and from densitydependent mortality of both mussels and barnacles which creates patches of new colonizable space within each environmental patch.

Notes: Abstract Respiration (dissolved oxygen and carbon dioxide) and excretion (dissolved organic carbon, inorganic and organic nitrogen and phosphorus) rates were measured for a variety of sizes of Mnemiopsis leidyi over a temperature range of 10.3° to 24.5°C. Both respiration and excretion rates were a direct linear function of animal weight and very temperature sensitive (Q10≊4). Oxygen uptake ranged from 155 to 489 μg at O/(g dry weight) day-1 and carbon dioxide release from 43 to 166 μM. Organic carbon made up about 38% of the total carbon released. Inorganic nitrogen excretion, exclusively in the form of ammonium, comprised 54% of the total nitrogen release and ranged from 10 to 36 μM NH4/(g dry weight) day-1. Average release of dissolved primary amines (expressed as glycine equivalents) equaled 43% of the organic nitrogen fraction. Inorganic phosphorus release ranged from 2.0 to 4.9 μM/(g dry weight) day-1 and made up about 72% of the total phosphorus loss. The turnover of elements in the body was calculated as 5 to 19% per day for carbon and nitrogen, depending on the temperature, and an even higher 20 to 48% per day for phosphorus. These values are comparable to rates observed for small, active zooplankton.

Notes: Abstract Because the rate of microbial degradation differs for the various sources contributing to the detrital pool in marine systems, their availability to detritivores might also vary. Carbon-14 tracer experiments were used to compare differences in the oxidation and net incorporation by the polychaete Capitella capitata of a nitrogenrich, easily-decomposable detritus derived from the red macrophytic algae Gracilaria sp. versus a nitrogen-poor, decay-resistant detritus derived from the eelgrass Zostera marina. The net incorporation of Gracilaria sp. detritus by C. capitata reached a maximum (91 μg dry weight of detritus/mg dry weight of worm/day) after only 14 days of decomposition, whereas that of z. marina detritus equaled this level after 30 days of aging, but continued to increase to 375 μg at 180 days. The oxidation rate of Gracilaria sp. detritus was consistently higher (peak of 61 mg dry weight of detritus/day at 30 day-aging) than z. marina detritus, which reached this level only after 180 days of aging. The presence or absence of C. capitata did not significantly alter the oxidation rate. The above difference might be attributed to a rapid exploitation and mineralization by bacteria of the more available Gracilaria sp. detritus, but a slow, “controlled” utilization by the microbes of the less available Z. marina detritus, especially during the early stage of decomposition. This would allow maximum exploitation of the substrate by macroconsumers, resulting in more of the detrital resource being tied up in detritivore biomass rather than being rapidly mineralized to CO2. Difference in the length of aging at which various detrital sources become available to detritivores could result in a temporal partitioning of food resources and should be considered in attempting to understand the dynamics of detrital-based food chains.

Notes: Abstract The phototropic reactions of pelagic larvae of Pachypygus gibber (Thorell) under laboratory conditions change according to their stage and their age. The behaviour of these larvae is described by 4 experimental parameters: threshold of the reaction, orientation towards the light or the opposite, speed and form of motility. Specimens were tested under different conditions of illumination. In the nauplii, the threshold reaction to light is higher than that in Copepodids 1 and 2. In the early planktonic stages (nauplii, Copepodids 1 and young Copepodids 2, from emergence to 3 days), most specimens respond positively to light, however the response is negative in older Copepodids 2 (4 to 10 days). There is a parallel evolution between the development of P. gibber and the change from positive to negative phototropism. The inversion of this response occurs in the developmental period between the 3-day old Copepodids 2 and the Copepodids 2 of 4 to 6 days of age. This reversal in vitro could correspond to the moment of penetration into the host. The average swimming speed is fastest in the positive phase of Copepodids 1, and is very slow in the older Copepodids 2. The form of the motility, rectilinear for most Copepodids 1, becomes increasingly winding as the Copepodids 2 grow. This random “exploration” of the environment would increase the possibility of finding the host. The evolution of phototropism is apparently related to the search for the host and its infestation.

Notes: Abstract Dry weight and body composition of C, H and N were investigated in male and female Tisbe holothuriae Humes fed 7 artificial compound diets and a living algal diet (Nannochloris sp.) over the whole biological cycle. No correlation was found between the respective proportion of C, H and N in the food and in the copepod body. Food quality had a significant effect on dry weight. Carbon content varied between 35.35 and 42.32% of body dry weight in females, and between 25.10 and 26.84% in males. Nitrogen values were 9.11 to 10.00% and 6.79 to 6.99%, respectively, varying with different diets. The C:N ratio varied between 3.74 and 4.28 in females and between 3.70 and 3.87 in males. Some diets had a significant effect on this ratio. In some experiments, three different temperatures were tested using the same diet. Body dry weight was inversely correlated with temperature, but no clear relation appeared between C:N and temperature. C:N variations were directly related to C concentration and seemed independent of N concentration. It is suggested that C variations correspond to different levels in lipid content under different trophic conditions. The relation between elementary chemical composition and fecundity in T. holothuriae fed different diets is discussed.

Notes: Abstract A monthly sampling programme was conducted to investigate aspects of the biology of a population of Mercenaria mercenaria (L.) Smooth growth curves were constructed for each year class, and the factors affecting growth rate were considered. Seasonal cycles in flesh weight and calorific content appear to be related to gonal proliferation and subsequent spawning. Recruitment is sporadic and probably depends on the spawning of upstream populations, where conditions are more favourable for larval development. Survivorship curves were constructed for each year class; predation by crabs and gulls appears to account for a large proportion of the observed mortality.

Notes: Abstract Measurements of the filtration rate and oxygen consumption of the bivalve Mercenaria mercenaria (L.) have been made using flowing water systems, and then combined with growth and survivorship data to construct an energy budget for a tidal-flat population in Southampton Water. Estimated consumption (1292 kcal m-2 year-1) is mainly deposited as faeces and pseudofaeces (759 kcal) or excreted (160 kcal); 29% (374 kcal) is assimilated, of which 241 kcal are used for respiration, 72 kcal for flesh production and 61 kcal for gamete production. M. mercenaria contributes significantly to other trophic groups in Southampton Water; predators remove an estimated 55 kcal m-2 year-1, and 829 kcal pass to the scavenger/decomposer chain.

Notes: Abstract In two experiments lasting 4 to 6 weeks, communities of North Sea coastal plankton kept in separate plastic bags (of about 1400 l) and exposed to the same environmental conditions showed very similar patterns of growth and decline. This result means that the method is suitable for the evaluation of toxic effects of environmental pollutants at low concentrations on complex plankton systems. The phytoplankton in the bags produced a succession of blooms, which were probably limited by shortage of nutrients. The dominant zooplankton organisms were various species of copepods which can develop in the bags from egg to adult. Strong indications were found that mineralization of organic matter occurs in the bags. Chemical parameters and phytoplankton biomass were found not to be stratified, indicating that the contents of the bags were well mixed.

Notes: Abstract Developing eggs of the winter flounder Pseudopleuronectes americanus (Walbaum) were exposed to 9 combinations of cadmium and salinity at 5° and 10°C. Overall mean times to 50% hatch ranged from 7.7 days at 10°C to 17.9 days at 5°C. Mean percentages of total hatches ranged from 50 to 100% for all treatment combinations. Response-surface analyses indicate percentages of viable hatches were generally lowest at 10% S and highest in the 25 to 30% S range. Regression analyses of viable hatch data show that at both temperatures cadmium significantly influenced viable hatch in all experiments. Viable hatch was also significantly influenced by the linear and quadratic effect of salinity in both tests at 5°C and in 2 of 3 tests at 10°C. The interaction between cadmium and salinity also significantly affected viable hatch at 10°C.

Notes: Abstract The fine structure of esophagus, stomach and intestinal epithelial cells of the sea urchin Strongylocentrotus droebachiensis have been examined. Three types of mucosal cells secreting neutral, acid and sulfated mucopolysaccharides have been found in the esophagus. The modes of origin of different types of mucous granules are described. Storage and zymogen cells have been identified in the stomach epithelium. Storage cells are adapted for intracellular digestion and synthesis of nutritive substance. Zymogen cells are adapted for enzyme synthesis. The columnar cells occur in the intestinal epithelium; they are adapted for nutrient absorption and lipid storage. Digestion in different parts of the digestive tract is considered in context with the ultrastructural and histochemical data obtained. Some problems concerning the relation between intracellular and extracellular digestion are discussed.

Notes: Abstract The reproduction of 9 species of littoral molluscs from the sub-Antarctic Macquarie Island was examined. The mode of larval development is reported for all species, and the reproductive patterns for 7 are described from collections taken monthly over a period of 1 year. Two species release gametes for external fertilization, whereas the other 7 have non-pelagic development via brooding or the laying of egg cases; some of these findings were deducted from examination of gonads rather than by direct observation. Features of reproduction important in any correlation between a littoral animal's reproduction and its habitat are discussed, and relationships between pelagic and non-pelagic development of the Macquarie molluscs and (a) distribution in the local environment and (b) habitat are drawn. The widely recognised correlation between species having a non-pelagic development and small number and large size of eggs is considered as a method for predicting the type of larval development (in terms of pelagic versus non-pelagic) from an examination of the ovary. It is suggested that further data on modes of development could be obtained from specimens of marine invertebrates collected throughout southern latitudes and that such data would enhance zoogeographical interpretations.

Notes: Abstract The effect of ambient ammonium concentration on the nitrate uptake rate of marine phytoplankton was investigated. These studies consisted of laboratory experiments using unialgal species and field experiments using natural phytoplankton communities. In laboratory experiments, ammonium suppressed the uptake rates of nitrate and nitrite. Approximately 30 min were required for ammonium to exhibit its fully inhibitory effect on nitrate uptake. At high ammonium concentration (〉3 μg-at/l), a residual nitrate uptake rate of approximately 0.006 h-1 was observed. When the ambient ammonium concentration was reduced to a value less than 1 μg-at/l, the suppressed nitrate uptake rate subsequently attained a value comparable to that observed before the addition of ammonium. A range of 25 to 60% reduction in the nitrate uptake rate of natural phytoplankton communities was observed at ambient ammonium concentrations of ∼1.0 μg-at/l. A mechanism is proposed for the suppression of nitrate uptake rate by ammonium through feedback control of the nitrate permease system and/or the nitrate reductase enzyme system. The feedback control is postulated to be regulated by the level of total amino acids in the cell.

Notes: Abstract In 1974 the authors collected, sorted and enumerated meiofauna from 400, 800 and 4000 m off North Carolina, USA. Samples were replicated respectively with 4 boxcores and 21 subsamples, 2 boxcores and 7 subsamples and 2 boxcores and 8 subsamples. Total meiofaunal numbers were highest in fine silt sediment at 800 m ( $$\bar x$$ =891.9 10 cm−2) and lowest in very fine silt at 4000 m ( $$\bar x$$ =73.5 10 cm−2). Fine sand at 400 m yielded a mean of 442.4 10 cm−2. At all depths, most fauna were located in the upper 3 cm of sediment ( $$\bar x$$ depth distribution=2.2 cm), and typically only nematodes and foraminiferans were found below 4 cm. Total community abundances significantly differed with depth; however, there were no differences among replicate boxcores at particular depths. Since most (85.7%) of the variance was associated with subsamples from a boxcore, it appears that meiofauna densities are homomeneous within large areas at particular depths, and that patchiness is a smallscale phenomenon at the level of the 10 cm2 subsampler. Comparisons of sorting efficiencies of live and preserved samples indicated that to accurately enumerate formainiferans, samples must first be fixed and stained, while turbellarians and oligochaetes must be sorted live.

Notes: Abstract The endogenous locomotor activity rhythm of Nephrops norvegicus (L.) shows peaks during darkness, around 3 h after dusk. At the peaks, activity occurs mainly within the burrow, although the prawns repeatedly vacate the burrows during the same periods. The phase of the rhythm shifts with a change of light-dark regime and in response to changed timing of “dusk” when “dawn” is fixed. Activity is suppressed immediately at dawn, but recommences before complete darkness during gradually reduced light at simulated dusk. This difference in response to light at dusk and dawn indicates phase responsiveness which is characteristic of endogenous rhythms entrained by light. The light-entrained endogenous rhythm is complementary to the rhythm of emergence which, reflected in commercial catches, appears to be controlled by exogenous factors.

Notes: Abstract In Chinquihue Bay, a sheltered locality in Southern Chile, female Crepidula dilatata Lamarck brood egg masses which differ in intracapsular development. In some, all eggs develop and are hatched as free veliger larvae (indirect development). In others, only some of the eggs develop and hatch as young adults (direct development), the rest being consumed as nurse eggs. Two possible interpretations are considered: intrapopulation variation of developmental pattern in a species, and the coexistence of two sibling species. Stages of the intracapsular development are described and illustrated. Fecundity varies according to size of the female. For females brooding eggs with indirect development it is estimated at between 3840 and 85575 embryos per spawn; for females with eggs undergoing direct development, embryo production per egg mass is estimated at between 70 and 812. A comparison is made between females brooding the two kinds of egg masses. Minor differences exist in adult coloration, shape of egg capsules, egg diameters, spawning season and their abundance and distribution in the intertidal. Brooding females with eggs displaying indirect development are significantly larger than those with eggs of direct development. The latter females form chains subtidally but not intertidally as do females bearing eggs with indirect development. On these females with pelagic larvae, chains frequently include sedentary males which reach large sizes. On basal females with direct development, chains contain mostly other females, suggesting that matings are temporary and by errant males. These results are compared with existing information in the literature for other species both in this genus and in other marine invertebrates. It is concluded that two sympatric sibling species with different modes of development are present in the morphospecies C. dilatata Lamarck in Southern Chile.

Notes: Abstract The uptake, storage and excretion of cadmium by the common mussel Mytilus edulis (L.) has been studied at sub-lethal concentrations using the radioactive isotope 115mCd as a marker. After an initial lag period, the uptake at low concentrations in sea water is linear with time and directly proportional to the sea water concentration, with a maximum concentration factor of 165 at 0.7 μg Cd/ml sea water. A decrease occurs at higher concentrations indicating saturation of the available binding capacity. Prior complexation of the cadmium with either EDTA, humic and alginic acids or pectin doubles both the rate of accumulation and the final tissue concentrations (order: kidney≫viscera〉gills≫mantle〉muscle) and eliminates the lag period, suggesting that ionic cadmium must first be complexed before uptake can occur. A mechanism for this effect, which may involve thionein, is described. The rate of excretion of cadmium is 18 times slower than that of uptake, with the major route via the kidney but not via the byssal threads as with particulate iron. The need to detoxify and store cadmium by an immobilization mechanism is a consequence of this slower rate of elimination.

Notes: Abstract Survival of individually reared larval and juvenile stage lobsters, Homarus americanus (Milne-Edwards), was significantly higher than in corresponding groups of communally reared individuals. Among communally reared lobsters, the mortality rate was highest in the second-stage larvae and then progressively decreased in the later stages. The relationship between survival and duration of molt period of each life-cycle stage indicates that asynchronous molting in the groups of communally reared lobsters is a contributing factor to the higher mortality rate. The molting and mortality curves of communally held lobsters reared from the first larval to first or second juvenile stage showed best cross correlation at 0- or 1-day time lag. The decreased mortality rate observed in the later larval and juvenile stages appears to have resulted from the establishment of new behavior patterns. Group interactions which are influenced by numerous extrinsic and intrinsic factors lead to higher mortality rate (“cannibalism”) among communally reared lobsters.

Notes: Abstract Effects of 0.01, 0.1 and 1.0 ppm methoprene (Altosid®: ZR-515), a juvenile hormone (JH) mimic which shows high activity against some economically important insect pests, especially Diptera, were tested on larvae of the mud-crab Rhithropanopeus harrisii (Gould) (Brachyura: Xanthidae) from hatching to the first crab stage under optimum and stress conditions of a number of salinities and cyclic temperatures. There was a significant reduction in survival of zoeal larvae with increasing concentrations of methoprene in nearly all combinations of salinity and temperature. On the average there was 9% less survival in the 0.01 ppm concentration of methoprene than in the control, and in the 0.1 ppm concentration the survival was further reduced by another 16%. At 1.0 ppm methoprene no larvae survived beyond the first zoeal stage under optimum conditions or under stressful combinations of salinity and temperature. Except at 0.2 ppm in 27.5% S, survival of the megalopa was not significantly reduced in 0.01 or 0.1 ppm methoprene in any salinity or temperature, although the percentage of abnormal megalopa increased under stress conditions. The first zoeal stage was the most sensitive of the larval stages to methoprene as well as to salinity and temperature stress. The duration of zoeal development was significantly lengthened with an increase in concentration of methoprene under nearly all conditions of salinity and temperature. The JH mimic had, however, no significant effect on the duration of megalopa development. A significant synergism between methoprene, salinity and temperature was not observed. It can be concluded from the results that methoprene does not inhibit metamophosis of R. harrisii larvae at the 0.1 ppm level or lower. Reduction in survival of zoeal stages and increased duration of zoeal development with increasing concentrations of methoprene are presumably related to stress.

Notes: Abstract The occurrences of K, Rb, Cs, Ca, Sr, Ba and Pb have been determined in various tissues of the tuna fish Thunnus alalunga. K, Rb, and Cs are distributed uniformly throughout the organs of the fish; 95% of the ca and Sr, and 70% of the Ba and Pb are contained in the skeleton. It is found that there are smaller amouts of Cs, Ba and Pb associated with the nutrient metals K and Ca in a marine animal compared to a terrestrial animal. This difference is a result of the purity of K and Ca in sea-water and the smaller amounts of trace metals associated with them compared to the impurity of K and Ca in terrestrial rocks. Food-chain enhancement and depletion of metals can be evaluated by comparing rations of trace metals to abundant nutrient metals in seawater and tuna. Cs is enriched relative to K in going from seawater to tuna by a factor of 13. Sr and Ba are both depleted by factors of 5 relative to Ca in going from seawater to tuna, while Pb is enriched relative to Ca by a factor of 14. Special clean laboratory procedures were used to prepare samples for accurate analysis by stable isotope dilution mass spectrometric techniques.

Notes: Abstract Effects of the juvenile hormone (JH) mimic hydroprene (Altozar®: ZR-512), which exhibits high activity against Lepidoptera, were studied on the larval development of the mud-crab Rhithropanopeus harrisii (Gould) (Brachyura: Xanthidae). Larvae reared in 20‰ S at 3 cycles of temperature of 20° to 25°C, 25° to 30°C and 30° to 35°C, were exposed to 0.01, 0.1 and 0.5 ppm hydroprene from hatching to the first crab stage. Larvae were also exposed to 0.1 and 0.5 ppm hydroprene only from the megalopa stage to the first crab stage. When larvae were treated with hydroprene throughout larval life, survival was significantly reduced with increasing concentrations of the compound at all temperature cycles. Synergistic effect between hydroprene and temperature on survival of zoeal larvae was not observed. On the average there was 11% less survival in the zoeal stages at the 0.01 ppm concentration. of hydroprene than in the control, an additional reduction of 13% occurred at 0.1 ppm, and finally there was a further decrease of 46% at 0.5 ppm hydroprene. Significant decrease in survival in the megalopa stage occurred only in the 0.5 ppm concentration of hydroprene at the lowest temperature cycle when larvae were exposed to the compound from hatching. When larvae were treated with hydroprene only within the megalopa stage, a significant reduction in survival was not observed. First-stage zoeae were the most sensitive of the larval stages to hydroprene. Duration of zoeal development was significantly delayed at 0.5 ppm hydroprene at the two lower temperature cycles, whereas in the megalopa stage the delay began at the 0.1 ppm level at all 3 temperature cycles when larvae were exposed to hydroprene from hatching. A significant delay was also observed at 0.1 ppm hydroprene at the two lower cycles when larvae were exposed to hydroprene only in the megalopa stage; at 30° to 35°C a significant delay was observed only at the 0.5 ppm level. The results show that metamorphosis to the first crab stage was not inhibited at the 0.5 ppm level of hydroprene or lower. Reduction in survival and increase in duration of larval development were presumably related to stress conditions caused by hydroprene. The results also suggest an interaction between temperature and hydroprene on survival of megalopa larvae and duration of larval development.

Notes: Abstract In 7 species of echinoderms, 2 species of polychaetes, and 1 species of oyster with feeding larvae, larger eggs were found to contain more organic matter. Although organic matter per egg increases with egg diameter or volume, it is not proportionate to egg volume, because small eggs have more concentrated organic matter than larger eggs. There appear to be differences among higher taxa in the minimum size of freely spawned eggs. These differences could result from different relationships between mortality and reduced egg size arising from differences between larval feeding mechanisms or differences in size at metamorphosis. An egg has more than five times the organic matter of a diatom of the same size and is thus a bigger meal for suspension feeders.

Notes: Abstract The shedding of gametes of Botryllus primigenus Oka occurs in the natural environment early in the morning, about 1 h after dawn. The shedding of the sperm from a testis is completed within a few seconds. All the spermatozoa in a testis are released at once. Ovulation begins about 10 min after shedding of sperm and is completed in about 1 min. In general, combinative testes, i.e., testes accompanied by egg follicles, macure first, followed by egg follicles, solitary testes located on the left side of the zooid, and finally those on the right side, in that order. As a result, a population of zooids of the same generation in a colony sheds sperm on 2 or 3 successive days. Illumination preceded by darkness effectively induces shedding of gametes experimentally. The required minimum dark-adaptation period is 40 min; the required minimum illumination period is dependent on light-intensity, 8, 4 and 1 min being required at 70, 200 and 3,000 lux, respectively; the latent period is temperature-dependent, 100 to 130, 70 to 90 and 50 to 60 min being required at 21o, 26o and 27.5°C, respectively. An experiment in which only part of the colony was illuminated clearly indicated that each zooid responds to light-stimulus independently.

Notes: Abstract Decerebrate, sexually immature juveniles of Ophryotrocha labronica develop into males and females, although the normal ratio observed in intact worms is not attained. Even without the prostomium, primary males split into secondary females and stable males. Stable males and females do not show any reaction after decerebration as far as sexual differentiation is concerned. The females proliferate new sets of oocytes and the males continue spermatogenesis. In a great number of cases, decerebrate secondary females resume spermatogenesis. Amputation of the prostomium induces the development of the k-jaw. Even in small individuals below the size at which the k-jaw normally appears, the change to the k-jaw is induced. Heterospecific transplantations of prostomia from female O. labronica donors to decerebrate O. puerilis hosts revealed that the prostomia of female O. labronica produce and release a substance which completely compensates the lack of the host's own prostomium. Obviously, this ootropic substance is not necessary in all cases for gaining and/or maintaining female differentiation in O. labronica. Although it is produced both in stable females and secondary females, only a portion of the secondary females requires this substance for female differentiation. It is, therefore, presumed that the strength or stability of female differentiation expresses itself by hormone-dependent or independent oogenesis. In crosses with a gonochoristic population of O. labronica, protandric hermaphroditism is restricted to a few descendants. Crossing experiments within the protandric population of O. labronica seem to indicate a genetic component in the degree of protandry and in sex determination.

Notes: Abstract A closed-circuit television system was used to study phototaxis and behavioral responses upon sudden decreases in light intensity in light-adapted Stage I zoeae from 7 species of Brachyura (Panopeus herbstii, Menippe mercenaria, Uca pugilator, Callinectes sapidus, Sesarma cinereum, Pinnotheres maculatum, and Libinia emarginata). All species except one show positive phototaxis to high intensities of 500 nm light and negative phototaxis to low intensities. Upon a sudden light intensity decrease, larvae show a shadow response, which depends upon the initial and final intensities. If the initial intensity is sufficient to induce positive phototaxis, and the light is extinguished, the larvae of 6 species stop swimming and passively sink (sinking response). Reducing the intensity to an absolute level that causes negative phototaxis, induces a sinking response followed by negative phototaxis. For intensity reductions that occur in the intensity range above that for negative phototaxis, a sinking responseis observed. The intensity decrease that initiates the sinking response is independent of initial stimulus intensity and duration, is consistent between species, and is equivalent to a decrease by 0.5 OD (optical density) units. The sinking response is greatest at intensity decreases of at least 1.0 to 1.1 OD units. It is concluded that the shadow response is common in brachyuran larvae inhabiting coastal-estuarine areas.

Notes: Abstract Balanus balanoides (L.) collected from an area with high heavy-metal run-off contained two different types of granule within the parenchyma cells of the prosoma. X-ray microprobe analysis shows one to be the familiar “zinc” granule made up of concentric layers and giving major peaks for phosphorus and zinc, and the other to be homogeneous and giving peaks for sulphur and copper. This latter granule is designated the “copper” granule. Whilst “zinc” granules are known to be composed of inorganic phosphate, various tests on “copper” granules in sections and in a granule-rich pellet have shown that the copper is probably complexed with organic matter. The tests also demonstrated the relatively, insoluble (inert) nature of these granules. Although “zinc” and “copper” granules were present together in the prosoma, atomic absorption analyses of whole bodies (prosoma+thorax) have shown the level of zinc (50.28 μg/mg dry weight) to be much higher than that of copper (3.75 μg/mg dry weight).

Notes: Abstract The condition index (CI) of the clam Rangia cuneata was measured monthly at 8 stations in 2 substrate types and 3 salinity regimes in the James River estuary, Virginia, USA. CI was higher in clams from sand bottoms than from mud, and decreased in both substrata in fresher water. Values were lowest in early spring and at a maximum in early autumn, with a pronounced autumn peak in the sand substratum. This pattern coincided with the annual salinity cycle. A field experiment showed that some factor associated with the water overlying a sand or mud substratum, rather than the nature of the substratum itself, was important in determining CI. The hypothesis is presented that this factor may be the higher suspended solids concentrations measured immediately over mud bottoms.

Notes: Abstract The rates of photosynthesis and dark respiration for 7 marine algae and 1 fresh-water alga were measured and compared. The dinoflagellates Glenodinium sp. and zooxanthellae have high dark respiration rates relative to photosynthetic rates, which may decrease their net growth rates. Photorespiration in the 8 algal species was studied by examining the effects of the concentration of oxygen on the rates of photosynthesis, on the incorporation of 14CO2 into the photorespiratory pathway intermediates glycine and serine, and on the postillumination burst of carbon dioxide production and oxygen consumption. A combination of these results indicates that all the algae tested can photorespire, but that Glenodinium sp., Thalassiosira pseudonana, and zooxanthellae either have a photorespiratory pathway different from that proposed for freshwater algae (Tolbert, 1974), or an additional pathway for glycolate metabolism.

Notes: Abstract A 5 year survey of Marsamxetto Harbour, Malta, was carried out to investigate some factors contributing to “red tides” and to identify the causative organisms. “Red tides” occurred usually in May but, less predictably, also during June – August. Causative organisms included the diatom Chaetoceros sp., and the dinoflagellate genera Prorocentrum, Peridinium, Ptychodiscus, Gonyaulax, Ceratium and Cochlodinium. Early summer red tides occurred at a time of increasing insolation, and water temperature, prevailing onshore winds and salinities in the range 34.4 to 36.6‰ A consistent feature was a quick rise in sea temperature of more than 2 Co during the week preceding red water. Red tides later in the year coincided with higher temperatures and salinities and calm weather.

Notes: Abstract Observations of the feeding biology of Meyenaster gelatinosus (Meyen) were made between Horcón and the southern Golfo de Penas, Chile. Of 811 sea stars examined, 436 were feeding on individuals representing 30 prey species. M. gelatinosus preys upon almost all the echinoderms and molluscs in its habitat, yet most of the prey species have extremely effective running escape behaviour in which they eventually release their attachment to the substratum, usually assuring that they will be swept to safety. Many of the molluscs exaggerate this by dorsoventral flattening of their mantles, so that they glide even farther. The echinoid Loxechinus albus has a very effective pedicillariae defense. Even at a distance, prey species usually discern foraging M. gelatinosus from non-foraging individuals, and on several occasions were observed touching M. gelatinosus which were eating conspecifics. Comparisons of the sizes of individual M. gelatinosus and their L. albus prey items showed no correlation; none of the prey species except possibly Concholepas choncholepas and M. gelatinosus itself has a refuge in size from attacking M. gelatinosus. The density of M. gelatinosus in 3 of 4 widely separated study areas where such data were collected was 0.04/m2. The mean radius of M. gelatinosus ranged from 150 to 210 mm in five study areas.

Notes: Abstract A hydrolysis procedure along with a high-pressure liquid chromatographic procedure is given enabling simple and reliable thymine determinations in the nanogram range in different fractions of sea-water samples taken from three different locations in the Northern Adriatic Sea. The levels corresponded to 1–3 μg DNA per liter. From total polyanionic thymine, which had been precipitated as the cetyltrimethylammonium salt, the highest percentage was linked to the particulate fraction, with a definite subsurface minimum at 10 to 15 m. There was a corresponding maximum of a high molecular “non-particulate” thymine-containing fraction at the corresponding depth. From the bottom at 30 m upwards to about 20 m, a low molecular thymine-containing material has been found. Remarkably these basic features were common to all three locations, one of which was supposed to be in clean water, one near a thickly settled, touristic area, and the other in front of a large river delta coming from industrial hinterland.

Notes: Abstract N2 fixation (C2H2 reduction) associated with the leaves of the sea grass Thalassia testudinum was investigated at 5 sites in South Florida (Biscayne Bay) and one site in the Bahamas (Bimini Harbor). Significant activities were correlated with the occurrence of a heterocystous blue-green alga (Calothrix sp.) on the leaves. C2H2 reduction was not stimulated by organic compounds, either aerobically or anaerobically in the light or dark. Therefore, other physiological types of microbes were not important in N2 fixation. Diurnal and seasonal variations in N2 fixation occurred, with maximal rates during the daytime and in the late spring and early summer. N2 fixation was negligible at four stations in Biscayne Bay. At the fifth station, near Fowey Rock, about 5 kg N ha-1 year-1 was fixed. In the summer, the N2 fixed per day (4–5 mg N m-2) could provide 4 to 23% of the foliar productivity demands of T. testudinum at this site and the station in Bimini Harbor. N2 fixation at the periphery of a sea-grass patch, near Fowey Rock, could provide 8 to 38% of the daily nitrogen requirement for leaf production, and thereby might compensate for a less effective trapping and recycling of nitrogen from dead leaves in such regions.

Notes: Abstract N2 fixation (C2H2 reduction) was associated with several species of macroalgae on a coral reef near Grand Bahama Island. The highest rates were associated with Microdictyon sp. (Chlorophyceae) and Dictyota sp. (Phaeophyceae). Extensive mats of filamentous blue-green algae, not heterotrophic bacteria, were the N2 fixing agents: in experiments with samples of Microdictyon sp., the activity was lightdependent and not stimulated by organic compounds under either aerobic or anaerobic conditions. Assays in situ, at 20 m depth, and on shipboard, gave similar rates of N2 fixation; the cyanophytes presumably have pigment adaptations to function in blue light. The maximum rate of N2 fixation, associated with Microdictyon sp., was 3.8 μg N fixed g dry weight-1 h-1. Coral-reef communities flourish in nutrientimpoverished waters, and therefore any input of nitrogen is probably important in stabilizing such ecosystems.

Notes: Abstract A study of phosphate assimilation by coastal marine plankton revealed that both phytoplankton and microheterotrophs incorporated radioactive phosphorus (33P). Size fractionation of the particulate matter (using 1 μm pore diameter Nucleopore® membrane filters), antibiotic treatment (using garamycin), and independent estimaties of photoautotrophic (14CO2 uptake) and heterotrophic (3H-glucose uptake) activities were employed to separate phyto- and bacterioplankton phosphate uptake. Results indicated that phytoplankton 33P-uptake was best estimated by the fraction of particulate matter retained on the 1 μm membrane filters. Usually, less than 10% of the phytoplankton (based on chlorophyll a measurements) passed the 1 μm pore-diameter filters, whereas about 90% of the heterotrophic activity passed. At least 50% of the 33P-uptake was associated with the 〈1 μm fraction. It may be possible to resolve the phytoplankton and bacterial contributions to 33P-uptake by comparing the percent of total 33P-uptake with the percent of total 3H-glucose uptake associated with the 〉1 μm fraction.

Notes: Abstract Phytoplankton populations are concentrated in surface microlayer waters of the York River and Mobjack Bay, Virginia, USA. The degree of vertical heterogeneity was variable and seemed most dependent on weather conditions (vertical mixing) and total phytoplankton cell densities. Vertical stratification also exhibited some taxocoenotic dependency. Structurally, the phytoplankton communities of the surface microlayer were less diverse than subsurface communities. In general, values of informational diversity (H'), evenness (J), and richness (S and r) are lowest in the surface microlayer and increase with depth (to 3.0 m). Mechanisms which structure and maintain vertical heterogeneity are discussed.

Notes: Abstract The estuarine benthic diatom Navicula arenaria Donkin was grown in perfusion chambers in which the cells adhered to analytical sand. A synthetic medium, containing various concentrations of orthophosphate, was continuously pumped through the cultures to prevent exhaustion of the medium. The division rates of the diatoms were independent of phosphate concentration in the medium from about 0.3 to 8 μg-at/l; lower concentrations were limiting (K S about 0.1 μg-at/l). The phosphate and chlorophyll a content of the N. arenaria cells was independent of phosphate concentration (even under limitation), except that the phosphate content of cells grown in media with 8 μg-at of phosphate increased. The data indicate that this benthic diatom uses low phosphate concentrations for growth as efficiently as several planktonic diatoms. The phosphate concentrations previously observed in the Eems-Dollard estuary (the original habitat of our strain of N. arenaria) were clearly higher than those limiting the growth rate of the cultures, and consequently may have no influence on benthic diatom growth.

Notes: Abstract Natural variability in the abundance of an intertidal population of the lamellibranch Macoma balthica (Linnaeus, 1758) was measured during 1971 and 1972 in a study area near the proposed oil storage and tankship loading facility at the southern terminus of the Trans-Alaska pipeline in Port Valdez, Alaska. M. balthica were divided for analysis into a large and a small size category. Small temporal changes in population densities throughout the entire study area were detected for both size categories over several of the 7 sampling times of the 2-year period. Large and persistent differences in density were found among elevation contour intervals for either size category; however, variations in the density profiles on elevation occurred among sampling times. Large M. balthica became more equitably distributed and the small category less equitably distributed among elevation contours over the 2-year period. Densities of both size categories were more stable at the higher elevations of the study site. Large M. balthica were more homogeneously distributed along a given elevation contour interval than the small category. Mobility and time available to redistribute at a horizontal location would explain the more homogeneous distribution of large M. balthica if competition for food resources exists.

Notes: Abstract The response of Aurelia aurita ephyrae to abrupt temperature and salinity differentials is expressed as changes in bell pulsation rates. Acute temperature rate-responses of Texas (USA) ephyrae reflect a reduced temperature sensitivity over a broad range (10° to 35°C), with a Q10 value of 0.97 between 20° and 25°C. The initial relationship between salinity change and pulsation rate is linear and direct. This pattern is disrupted after 24 h, with those ephyrae experiencing a salinity decrease pulsing significantly faster than those experiencing no change or an increase in salinity. This response to low salinities dissipates after 2 days. Holding osmotic pressure constant and disrupting ionic ratios has more of an immediate and persistent effect than solely decreasing salinity.

Notes: Abstract Simultaneous flow measurements were performed by hot-wire anemometry inside and outside (a) a closed bag, and (b) a flow-through system designed for metabolic experiments of Fucus vesiculosus communities. Since water movement is considered an important parameter in such biological studies, the walls of the systems were flexible in order to establish flow conditions within the enclosed water body comparable to those in the natural environment. In situ experiments in the Baltic Sea at a water depth of 2 m showed that energy spectra inside the systems were comparable to those outside for a variety of flow and wave conditions. Thus, biological data from glexible wall systems, carefully designed to meet specific natural flow requirements, can be taken as reliable input data for natural ecosystem modeling.

Notes: Abstract Settling larvae of the bryozoans Flustrellida hispida, Flustra foliacea, Alcyonidium polycum, and Bugula neritina exhibit a common behavioral pattern. A settlement site is selected after initial exploration, and temporary attachment is accomplished with a sticky acid mucopolysaccharide secretion exuded from the pyriform organ. Permanent attachment is accomplished by acid mucopolysaccharide and protein secretions of the everted internal sac.

Notes: Abstract Sublethal effects of mercury, cadmium and copper on the diatom Skeletonema costatum (Grev.) Cleve, grown in batch and bacteria-free culture are studied. Division rate, maximum yield growth, mean cell volume, particulate carbon and nitrogen, and 14C-bicarbonate uptake are used as toxic impairment criteria. Division rate is the first-affected and most sensitive parameter, but algal responses vary according to the metal. Hg produces an acute decrease in division rate, followed by a temporary recovery of growth capacity within the first 48 h after metal addition. Cd, on the other hand, increases division rate, followed by an obvious decrease. Cu reduces division rate slowly or quickly, depending on the metal concentration. Cell synthesis capacity (culture biovolume, particulate carbon and nitrogen, carbon assimilation) is less affected than division rate, especially with Hg. The C:N cell ratio is unchanged at sublethal concentrations, even when production is reduced. The mean cell volume is slightly affected: the variations are not greater than those of the control during its growth phases. Markedly teratological forms are never observed. In the authors' opinion, these results confirm that many parameters and growth kinetic aspects must be considered to fully appreciate the effects of sublethal concentrations of heavy metals. It would also be of advantage to develop a better methodology for such research, applying, for example, techniques already employed in enzymology.

Notes: Abstract A large number of biotic relationships among dissimilar organisms is characteristic of tropical coral reefs. Such relationships involve at least four of the 16 species associated with the coral Pocillopora damicornis (L.) at Heron Island on the Great Barrier Reef. Behavioural interactions among the most conspicuous resident species (2 fish, 1 crab and 1 shrimp) were studied in the field under natural and experimental conditions. The inhabitants have the potential to harass, capture and eat, or exclude one another from the coral habitat but a system of signals among the residents facilitates coexistence and maintains the integrity of the community. The signals include contact and shivering movements by the fish which apparently inform the crustaceans of the fish's resident status.

Notes: Abstract Pieces of branch from the staghorn coral Acropora acuminata were incubated with 45CaCl2 and NaH14CO3 under identical conditions in the light or in the dark. Specimens were then processed in different ways. All specimens were placed in N KOH to digest tissues. Some were placed in KOH immediately after incubation; others were placed in KOH after 2 h washing, or after 2 h extraction with methanol-chloroformwater. Specimens were washed in running fresh water or running seawater; some were killed in liquid N2 before washing. Radioactivity associated with skeleton and tissues was determined. The method of processing profoundly affected the results. In dark incubations, there was up to a four-fold difference in apparent skeletal incorporation of 45Ca++ between average values obtained for the different treatments. For 14C incorporation, there was a difference of up to 2.5 times. In light incubations, skeletal incorporation of both radioisotopes showed a two-fold difference between high and low average values obtained for the different treatments.

Notes: Abstract Observations have been made on the biology of spiny lobsters, Palinurus elephas Fabr., caught by divers on the west coast of Scotland from 1972 to 1975. P. elephas in this Scottish population show the same length/carapace length relationship as spiny lobsters taken from the west of Ireland. It occurs inshore during the period April to October on shallow rocky reefs in depths of 5 to 20 m. In females, a pre-mating moult occurs in the inshore areas in late summer. Soon after, mating takes place and the spermatophores are deposited on the sternum of the female. The eggs, which are shed within 1 week to 10 days, are then carried by the female throughout the winter, and hatch in the following spring. Offshore migration takes place in the autumn, after mating and egg laying, and inshore migration takes place in the spring and summer.