The biology of colonial hydroids. I. The morphology of the polyp of Eirene viridula (Thecata: Campanulinidae)

The colonial marine hydroid Eirene viridula Peron and Lesueur (Thecata, Campanulinidae) is readily maintained under laboratory conditions and reproduces in both vegetative and sexual modes. Polyps from these colonies displayed 4 distinct body regions, which were studied by comparison of light and electron micrographs of semi-thin and ultra-thin sections. Attention was directed chiefly to the epitheliomuscular and digestive muscle cells, found in all 4 regions and characterized by the presence of a central vacuole. Particular emphasis has been placed upon the coated vesicles and discoidal coated vesicles, which appear side by side in the digestive muscle cells of the stomach, and upon the central vacuoles typical of the muscle cells of the contractile parts of the body. The possible functional significance of these structures is discussed.This work was supported by the Deutsche Forschungsgemeinschaft.     

Physiology of the digestive tract of the sedentary polychaete Terebellides stroemi

The digestive tract of the sedentary polychaete Terebellides stroemi, collected from 88 m depth on the French Catalan Coast, was studied using histological, biochemical, cytological and spectrographic techniques. The ciliated oesophagus possesses a ventral pharyngeal pouch with a muscle bulb. The stomach is divided into two parts, the fore stomach is ciliated, but the hind stomach takes the place of a gizzard with a thick peritrophic membrane and a thick muscle mantle. The digestive gland enters the digestive tract at the boundary of the two stomachal areas; it is comprised of epithelial lamellae with a glandular epithelium. The gland cells contain a spherocrystal secretion with a high calcium and phosphorus content. The cells are also absorbant due to their microvillar brush border and to the storage of glycogen and lipids in the basal epithelium. A biochemical study using the Apizym System confirmed the secretion of enzymes such as phosphatases, esterases and various carbohydrases. Tryptic and chymotryptic enzymes were visualized by biochemical hydrolysis of synthetic substrates. The epithelium of the fore intestine is similar in appearance to the epithelium of the digestive gland, but consists of a single epithelial layer. Hind intestine and rectum are only excretory systems. The presence of this digestive gland does not seem to have been described elsewhere in polychaetes but is similar to the Morren's gland of some oligochaetes. The study was carried out during 1982 and 1983.     

Distribution of the early-life phase of the Antarctic squid Galiteuthis glacialis in relation to the hydrology of the Southern Ocean in the sector 15° to 30°E

During R.R.S. Discovery Cruise 100 in the Southern Ocean (1979), 620 specimens of the Antarctic cranchiid squid Galiteuthis glacialis (Chun) were caught in the RMT8 opening-closing net, to the south of the Antarctic Polar Front (APF). The catch was dominated by individuals <20 mm dorsal mantle length (DML) and, apart from two specimens, the rest of the catch was <60 mm DML. Two larger squid (255 mm DML) were both immature and apparently female. The species is concentrated at a depth of 300 to 400 m; there is evidence of ontogenetic spreading and a shift in the modal depth of the population from the 300 to 400 m horizon in daylight to the 200 to 300 m horizon in darkness. The collection confirms the circumpolar distribution of the species and supports previous evidence that it rarely, if ever, occurs to the north of the APF. As in Mesonychoteuthis hamiltoni, the only other species of cranchiid squid known to occur south of the APF, the early-life phase of G. glacialis is concentrated in the upper zone of the warm deep water beneath the Antarctic surface layer where, putatively, there is a zone of enhanced biological activity.     

Sodium regulation in the shore crab Carcinus maenas as related to ambient salinity

The activity of Na–K-ATPase was measured in crude homogenates prepared from various organs (leg muscle, pincer muscle, heart, testes, digestive gland, hypodermis, gills 1–9) of shore crabs, Carcinus maenas L., acclimated to salinities ranging between 10 and 50 S (in steps of 10 S). In all salinities tested, Na–K-ATPase activity was highest in posterior gills 7–9 (10–12 mol P_i mg protein^-1 h^-1), followed by anterior gills 1–6 (ca. 2.5 mol P_i mg protein^-1 h^-1) and the other organs (in most cases far below 2mol P_i mg protein^-1 h^-1). In gills only, Na–K-ATPase activity was salinity-dependent, with the highest values in the lowest salinities and vice versa. In gills 7–9, Na–K-ATPase activity was increased more than threefold following a reduction in salinity from 50 to 10 S. Na–K-ATPase activity, expressed as percentage of total ATPase activity, amounted to 60–80% in gills, about 60% in hypodermis and 20–40% in the other organs. Ouabain, a specific inhibitor of Na–K-ATPase activity, reduced serum osmolalities in crabs kept at 9–10 S only when injected into the hemolymph (1 and 5 · 10^-5 M), but had no effect when dissolved in ambient water (10^-4 M). The results obtained underline that crustacean gills are the main organs for ionic regulation, and confirm the hypothesis of the central role of the Na–K-ATPase in active Na uptake as the basic mechanism of hyperregulation in dilute media. Reduction of serum osmolalities following injection of ouabain into the hemolymph confirms previous reports on localization of the sodium pump in the basolateral parts of epithelial cells.     

Petroleum hydrocarbons in the marine bivalve Venus verrucosa: accumulation and cellular responses

Cellular and subcellular responses of the marine burrowing bivalve Venus verrucosa collected from the north-eastern coastline of Malta from January to June 1985, after exposure to petroleum hydrocarbons (PHC) were investigated. After long-term exposure to 100 gl^-1 of water-accomodated fractions (WAF) of crude oil, PHC were found to accumulate most rapidly in the digestive gland and then in the gills, with saturation levels being reached within 100 d of exposure in both cases. PHC accumulation, both in the mantle and muscle tissues, was more gradual and consistent throughout the whole exposure period. After 150 d of exposure, the digestive cells of the digestive gland were significantly reduced in height (atrophy) and exhibited reduced lysosomal membrane stability. After 144 h of exposure to higher concentration of PHC (820 and 420 gl^-1), several cytological effects were recorded, including an increase in cell volume and activity of gill mucocytes as well as in the number of haemocytes in gill blood sinuses. There was also evidence of damage to the epithelial lining of the foot, stomach and style sac and marked atrophy of the digestive cells of the digestive gland. The significance of such responses is discussed.     

The common mussel Mytilus edulis as an indicator of trace metals in Scandinavian waters. II. lead,iron and manganese

An investigation of the mechanisms of detoxication of copper and zinc by the oyster Ostrea edulis (L) has been carried out using naturally occurring green-sick (contaminated by copper) and unpolluted oysters. Electron microprobe X-ray analysis of tissues in the electron microscope gives direct evidence for the structural compartmentation of copper and zinc in separate, specific, granular amoebocytes. The metals are immobilized in membrane-limited vesicles as different chemical compounds, copper being associated with sulphur and zinc with phosphorus. Chemical analyses of serum and tissues of normal and green-sick oysters indicate that (a) Cu and Zn are accumulated independently, (b) the Cu and Zn in the serum, while higher than in the surrounding sea water, are maintained at a 10-fold smaller level than the tissues, (c) toxicity is reduced by active uptake from the serum into granular amoebocytes, where it is further reduced by compartmentation in membrane-limited vesicles. It is calculated that the individual cell types may contain as much as 13,000 ppm Cu and 25,000 ppm Zn.     

Temporal variation and distribution of trace metals in freshwater and fish from Calabar River, S.E. Nigeria

An investigation on the abundance and distribution of trace metals (Fe, Cu, Zn, Mn, Cr, Cd and Pb) in water, and nine species of fish samples from Calabar river was carried out in 1992. The concentrations of iron (6000–7240gl^–1), zinc (4910–7230gl^–1), and cadmium (3–7gl^–1) showed moderate pollution while those of copper (420–630gl^–1), manganese (23–48gl^–1), chromium (<10–20gl^–1) and lead (<1–10gl^–1) in water were well below WHO permissible levels. Significant seasonal changes (0.001p0.25) were obtained for iron, copper, zinc, manganese and cadmium in water. Furthermore, iron, zinc and cadmium showed statistically significant spatial changes (0.005p0.10). Of the nine fish species studied, no statistically significant relationship between body weight and the concentrations of the metals was observed. The concentrations of the metals per mean total body weight apparently decreases in the order Fe>Zn>Cu>Mn>Pb>Cd=Cr and were within the limits that were safe for consumption.     

Adaptations to osmotic stress in the fresh-water euryhaline teleost Tilapia mossambica. IV. Changes in blood glucose,liver glycogen and muscle glycogen levels

Some aspects of osmoregulation energetics have been studied in the euryhaline teleost Tilapia mossambica (Peters) acclimated to media of different salinities. In stress media (75 and 100% sea water) the blood glucose of the fish increases significantly, accompanied by a corresponding increase in oxygen consumption and cytochrome-oxidase activity, suggesting that oxidative degradation of blood glucose is the predominant energy source for osmotic work in these stress media. It is likely that the variations in the blood-glucose level as a function of acclimation to the heterosmotic media —except the natural fresh-water medium — are governed by the combined effects of salinity of the medium and blood-medium osmotic gradient, rather than by the effect of any one of them separately. Perhaps, metabolic homoeostasis is in operation in the natural fresh-water medium. Depletion of muscle glycogen at significant levels is noticed only in stress media. Presumably, there is an augmentation of oxidative metabolism with glycolysis to meet the exacting energy demands for heavy osmotic work in high-stress media. Prior acclimation to 75% sea water (24.375 S) facilitates subsequent acclimation to 100% sea water (32.50 S) with less energy cost —an instance of facilitation acclimation. Smaller individuals of T. mossambica osmoregulate with less energy expenditure than larger ones. Thus, smaller individuals are osmotically more efficient.     

Carapace and branchial water circulation,and water-related behaviours in the semaphore crabHeloecius cordiformis (Decapoda: Brachyura: Ocypodidae)

Water uptake, branchial water circulation and various water-related behaviours and anatomical specialisations, are described for the Australian semaphore crabHeloecius cordiformis (H. Milne-Edwards 1837). Male and female semaphore crabs were observed and collected from mangrove swamps around the south side of Botany Bay, Australia between 1983 and 1987. Semaphore crabs are active at low tide in air. Their branchial chambers are modified for both air breathing and water circulation. Water is held within the branchial chambers and is used for feeding and, to a certain extent, respiration. Crabs carry between 0.35 and 0.5 ml of water (7 g live body wt). Branchial water is continuously pumped out by the scaphognathites over specialised setae-bearing regions of the carapace and back through the branchial chambers over the gills, in a manner similar to that found in many grapsid crabs. Setae associated with water circulation are described. Water falling ventrally is collected by the abdominosternal cavity (formed between the abdomen and sternum) from where it returns to the branchial chambers via branchiosternal canals. Several novel water-related behaviours are described: Water shoogling — branchial water is drawn out between the walking legs where it is worked by scissor-like up and down movements of the legs. Abdomen flap — branchial water volume is adjusted by the extension and flexion of the abdomen against the cephalothorax. Water dumping — by tilting forwards and kissing the substrate, branchial water is voided to allow an entirely fresh load to be taken up. Statuesque posing — crabs remain erect and motionless for long periods. Branchial water is absent and external body surfaces dry out. Posing behaviour may function in thermoregulation, osmoregulation or as an anti-fouling mechanism against settling organisms. The significance of these various behaviours is discussed.     

The respiratory metabolism of Tilapia mossambica (Teleostei)

Tilapia mossambica (Teleostei) weighing 5 to 80 g were acclimated at 30°C to salinities of 0.4 (tap water), 12.5 (50% sea water) and 30.5 (100% sea water). Their respiration was measured at routine activity and the partial pressure of ambient oxygen gradually reduced from 250 to 50 mm Hg. Respiration is salinity-dependent; the proportionate ability to use oxygen in any one salinity is — above the critical pO₂ —the same in all experimental groups. This ability is a function of temperature and increases from 15° to 30°C, becoming temperature independent from 30° to 40°C as long as the pO₂ remains above 150 mm Hg. At 50 mm Hg pO₂, the limiting effect of oxygen causes a decrease in metabolic rate. This limiting effect is minimal in 80 g fish kept in an isotonic medium (12.5 S), allowing greater scope for activity and a higher rate of oxygen uptake.     

Populational distribution I: The digital simulation

This paper presents a method of investigating the distributional pattern of a biological population, using a technique of simulation. The method consists of the comparison of the empirical frequency curve of a population, obtained using the Method of Quadrats, with a simulated one, since the pattern of the simulated curve depends on the simulated distribution. An example is given.     

Response of the predatorRhizophagus grandis to host plant derived chemicals inDendroctonus micans larval frass in wind tunnel experiments (Coleoptera: Rhizophagidae,Scolytidae)

Summary Adults of the predatory beetleRhizophagus grandis are strongly attracted to both adult and larval frass of its specific prey,Dendroctonus micans, in walking bioassays. Spruce bark and resin are relatively unattractive. Solvent extracts of larval frass that were attractive toR. grandis adults in a flight wind tunnel contained a mixture of monoterpenes of host plant origin. A synthetic mixture of these monoterpenes, (+)—-pinene, (–)—-pinene, -phellandrene,dl limonene and 3-carene, was responsible for 70–80% of the activity of the most attractive extract. We suggest that a blend of monoterpenes in frass acts as a kairomone forR. grandis but that attraction to monoterpenes is only the first of a sequence of behavioural responses that ensures successful host location and identification.     

Geochemistry of an arsenic anomaly in St. Elizabeth, Jamaica

A soil arsenic anomaly with concentrations up to 400g As g^–1 was discovered near Maggotty, St. Elizabeth, during an islandwide geochemical survey of Jamaica. Detailed sampling and chemical analysis of soil samples confirmed the arsenic levels and led to a better definition of the size of the anomaly. The area exceeding the 95th percentile (>65g As g^–1) of the islandwide concentrations has been determined to be at least 10km². The anomalous values may be the result of an ancient hot spring environment which was responsible for the introduction and deposition of Fe–As–S as pyrite and arsenopyrite in the limestone bedrock, which were subsequently oxidised and weathered to yield the arsenic rich soils. These soils were also enhanced in elements such as Sb, Fe and Co. Despite the high soil arsenic content, the arsenic concentration in the surface water is low and there seems to be no immediate health risk to the residents. The area, however, does present a potential hazard with changing land use.     

Environmental Geochemistry of Soils and Waters of Susaki Area, Korinthos, Greece

Soil and water samples were collected from the Susaki area of Korinthos and analysed for heavy metals in order to evaluate their environmental impact. The geology of the studied area includes ultrabasic rocks and Neogene and Quaternary deposits whereas magnesite veins are found within the ultrabasic rocks. In the north part of the studied area post volcanic emissions of H₂S, CO₂ and H₂O vapor continue to the present day. All the samples were analysed for heavy metals by the ICP method. The element ranges (in g g^–1) for soil samples are: Cu 11–63, Pb 5–256, Zn 21–604, Ni 183–2665, Co 12–124, Mn 456–1434, As 5–104, Sr 44–730, V 21–84, Cr 163–2346, Ba 48–218, Zr 3–41, Y 3–13. The metals Pb, Zn, Ni, Co, Cr, Fe, Cu, Mn, As and Sr are enriched in the Susaki soils. The element ranges for water samples are: Cu 65–103ppb, Pb<10ppb, Zn<5ppb, Ni 21–163ppb, Co 2–12ppb, As<30ppb, Cr<20ppb, Ba 36–785ppb, Sb<10ppb, W<10ppb, Bi<30ppb, Mn 0.0–0.9 g g^–1, Fe 0.01–0.22 g g^–1, Na 843–3076 g g^–1, K 98–278 g g^–1, Si 39–65 g g^–1, P 0.1–0.2 g g^–1. There is a natural pollution of soils with elevated concentrations of Ni, Co, Mn, Fe and Cr due to the presence of ultrabasic rocks. Another natural case of As pollution of soils is due to the volcanic activity and the geothermal field in the area. The geochemical data of ground waters and also the ¹⁸, D data showed a mixing in different proportions between sea water and meteoric water.     

The poison gland of the antMyrmicaria eumenoides and its role in recruitment communication

Summary The antMyrmicaria eumenoides is a significant arthropod predator. For rapid attraction of large numbers of nestmates to newly discovered food sources the ants use an efficient recruitment communication system based on the poison gland secretion. Workers exhibit age-based division of labour. Young workers perform brood-care; their poison gland reservoir develops and reaches its final size of 0.5 µl at an age of 6 weeks, when they become foragers. The secretion deposited during combat with enemies or prey is composed of equal amounts of both a high volatile and a low volatile fraction. Within the high volatile fraction (+)—limonene is the main component (97%) and is the only olfactory trigger to alert ants in the vicinity and to recruit them to places of combat, where they assemble. Ants respond to synthetic (+)—limonene in exactly the same way as to the poison gland secretion when applied at the same airborne concentrations. Further components of the high volatile fraction are four additional monoterpene hydrocarbons and hexanoic nitrile. The high volatile and the low volatile fraction of the poison gland secretion each have dual functions: The low volatiles, of which the main component is an alkaloid, serve as a fixative and extend the effective period of the limonene signal by modifying its evaporation kinetics. On the other hand the high volatile recruitment signal (+)—limonene is also the solvent for the alkaloid and enhances its spreading on the surface of the cuticle of arthropod enemies or prey.     

The functions of octopine dehydrogenase and D-lactate dehydrogenase in the pedal retractor muscle of thedog whelk Nassarius coronatus (Gastropoda: Nassariidae)

The pedal retractor muscle of Nassarius coronatus, unlike most mollusc muscles, contains high activities of both octopine dehydrogenase (159 IU g^-1 wet wt muscle) and D-lactate dehydrogenase (40 IU g^-1 wet wt muscle). Pedal retractor muscles show accumulation of octopine (increase of 4.7 mol g^-1 wet wt muscle), and a fall in arginine phosphate concentration (decrease of 4.1 mol g^-1 wet wt musscle) after exercise. During recovery from exercise, octopine returns to resting levels after about 120 min, D-lactate accumulates (5.1 mol g^-1 wet wt muscle), and arginine phosphate returns to resting levels within 30 min. D-lactate (2.0 mol g^-1 wet wt muscle) accumulates during long-term exposure to air. The results show that octopine dehydrogenase and D-lactate dehydrogenase can function to catalyze the terminal step of glycolysis during muscle anoxia associated with these different physiological states.     

Lead Contamination of Topsoil and Vegetation in the Vicinity of a Battery Factory in Nigeria

Levels of Pb, Zn, Cu, Cr, Ni and Cd were determined in topsoil and vegetation in the vicinity of a factory manufacturing lead- batteries in Ibadan, Nigeria. The samples were collected along five transects in different directions, and varying distances up to 1000m from the factory. Soil lead levels were found to be elevated around the factory, with average levels of about 2000mgkg^–1 close to the fence that declined gradually to about 50mgkg^–1 some 750m away. Soil-lead level around a primary school located about 500m from the factory was as high as 1450mgkg^–1. Lead levels were equally elevated in the vegetation, though average levels in vegetation were slightly lower than in the soil. Cadmium concentrations in soil and vegetation, though low, were more positively correlated with lead levels than any of the other metals are with lead.     

Similarity-based testing for community pattern: the two-way layout with no replication

The large, sparse arrays of species counts arising in both field and experimental community studies do not lend themselves to standard statistical tests based on multivariate normality. Instead, a valid and more revealing approach uses informal display methods, such as clustering or multi-dimensional scaling ordination (MDS), based on a biologically-motivated definition of pairwise similarity of samples in terms of species composition. Formal testing methods are still required, however, to establish that real assemblage differences exist between sites, times, experimental treatments, pollution states, etc. Earlier work has described a range of Manteltype permutation or randomisation procedures, making no distributional assumptions, which are termed ANOSIM tests because of their dependence only on (rank) similarities and the analogy to one and two-way ANOVA. This paper extends these tests to cover an important practical case, previously unconsidered, that of a two-way layoutwithout replication. Such cases arise for single samples (or pseudo-replicates) taken in a baseline monitoring survey of several sites over time, or a mesocosm experiment in which treatments are replicated only once within each experimental block. Significance tests are given for the overall presence of a treatment (or time) effect, based on a measure of concordance between rank similarities of samples within each block (or site); the role of the two factors can be reversed to obtain a test for block effects. As in the analogous univariate ANOVA test, the method relies on absence or relative weakness of treatment x block interactions. Its scope is illustrated with data from two experimental and two field studies, involving meiofaunal communities from soft-sediment and macro-algal habitats. It is seen also to accommodate a modest derree of missing data. Whilst the failure to replicate adequately is not encouraged—a richer inference is available with genuine replication—the paper does provide a limited way forward for hypothesis testing in the absence of replicates.     

Ultrastructure of the gill of the hydrothermal-vent mytilid Bathymodiolus sp.

Specimens of Bathymodiolus sp. were collected at 2 620 m depth during the Biocyarise Cruise (12°5880N; 13°5660W) in March 1984, and samples of the gill were fixed for ultrastructural observations. The gill of this hydrothermal-vent mytilid constitutes the main organ in the nutritional processes. The lamellae display abundant ciliation, normally comprised of frontal cilia, compound latero-frontal cirri and lateral cilia. At the ventral margin of each demi-branch, a longitudinal, ciliated, feeding groove is present. the lamellae are composed of numerous homorhabdic filaments connected by tufts of cilia. Each filament is made of a thin wall overlying a central lumen containing amoebocytes. Ultrastructural observations revealed the filament wall to be composed of four types of cells: (1) The ciliated cells of the frontal, latero-frontal and lateral ciliation, characterized by an abundance of mitochondria. (2) Mucous cells present to some degree among the ciliated cells, but more abundant on the distal edge and containing dense droplets of mucus. (3) Cells colonized at their apical pole by numerous bacteria enclosed in membrane-delimited clear spaces and composing the major part of the filament wall. (4) Thin ciliated cells separating the bacterial cells and characterised by a dense fringe of microvilli at their apical pole. The lumen of the filament contains amoebocytes of different morphological aspects which seem to accumulate electron-dense granules, possibly related to detoxification processes.     

Background levels of soil beryllium in several countries

Beryllium and aluminium contents in uncontaminated soils from six countries are reported. The means and ranges of beryllium in the surface soils were as follows: 1.43(0.20–5.50)g g^–1 in Thailand (n=28), 0.7 (0.31–1.03) g g^–1 in Indonesia (n=12), 0.99(0.82–1.32) g g^–1 in New Zealand (n=3), 0.58(0.08-1.68)g g^–1 in Brazil (n=16), 3.52(2.49–4.97)g g^–1 in the former Yugoslavia (n=10), and 1.56(1.01–2.73) g g^–1 in the former USSR (n=8). The mean and range of beryllium contents of the surface soils in Japan (1.17(0.27–1.95)g g^–1 n=27) are situated within the values of the soils from these countries except for the Yugoslav soils derived from limestones. The mean of the mean beryllium contents of the surface soils in all these countries is 1.42 g g^–1 which will be used as a tentative average content of beryllium in uncontaminated surface soils, except for the soils derived from parent materials high in beryllium content. The beryllium contents of the subsoils were higher than those of the surface soils in New Zealand and Yugoslavia as is the case with Japan. The correlation coefficient between the contents of beryllium and aluminium in all the soil samples (n=113) including surface soils and subsoils was 0.505 (p < 0.001).