Fission and its effect on population structure of Holothuria atra (Echinodermata: Holothuroidea) in Taiwan

Populations of Holothuria atra Jaeger occurring at Wanlitung and Nanwan were sampled monthly at spring tide from March 1990 to February 1992 in southern Taiwan. At Wanlitung, small individuals with evidence of fission and regeneration were abundant in shallow tidepools on the wide reef flats (density: 98±40 ( ± SD) 100 m^-2, body weight: 6 to 182 g). At Nanwan, large individuals with no evidence of fission were sparse in deep tidepools and narrow flats [density: 0.24±0.07 ( ± SD) 100 m^{- 2}, body weight: 351 to 1400 g]. At Wanlitung, fission occurred throughout the year with an average monthly fission frequency of 4.5%, peaking at 18% in September 1990 and 16% in August 1991. Fission was accomplished by revolving, twisting, and stretching of the body, resulting in two unequal fragments. The minimal weight of 3007 individuals measured during 1 yr at Wanlitung was 6 g. All ten individuals weighing 6 to 9 g ( ± SD = 6.7 ± 1.1) 100 m^{- 2} showed evidence of regeneration from fission products. Nine large individuals (>500 g) transferred from Nanwan to Wanlitung and 50 small individuals (<100 g) transferred from Wanlitung to Nanwan in February 1991 showed no evidence of fission during the following year. Fission occurs in small individuals living in shallow tidepools, suggesting that fission probably is triggered by a stressful environment resulting from solar radiation at the unusually low water level of spring tide. Fission of H. atra at Wanlitung results in a population consisting of small individuals.     

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.     

Response of gametophytes of Ecklonia radiata (Laminariales) to temperature in saturating light

Gametophytes of Ecklonia radiata (C.Ag.)J.Ag. from two New Zealand locations with different field temperature ranges were exposed to temperatures of 5° to 26°C in saturating light. Plants from Goat Island Bay (Lat. 36° 16S, Long. 174°48E) grew in 9.3° to 25°C and reproduced in 9.3° to 24°C. There was no growth at 8°C and plants died at 26°C. Plants from the cooler location, Houghton Bay (Lat. 41°20S, Long. 174°40E), grew from 8° to 24°C and reproduced up to 15°C but not at 21.5°C. The plants did not grow at 6°C and died at 26°C. The timing of the first cell division and subsequent growth rate were retarded close to the upper and lower tolerance limits. Reproduction was a broad optimum of roughly 12° to 20°C. Within this range, fertile female gametophytes grown at lower temperatures had fewer, larger cells and thus fewer potential ova than those grown at higher temperatures.     

Hyperiid amphipods in the eastern part of the South Pacific gyre

Studies were made of Amphipoda Hyperiidea collected in 1987 with a pelagic trawl in the South Pacific anticyclonic gyre in the vicinity of the Nazca and Sala y Gómez ridges (17°35 to 26°01S, 80°10 to 100°50W), at depths ranging from 50 to 300 or 600 m. Forty-three hauls contained 7 198 specimens, comprised of 119 species within 43 genera. Two of the species appeared to be new for science; two others were found in the Pacific Ocean for the first time. A comparison with hyperiid collections from other tropical Pacific regions revealed great stability of oceanic faunal composion. However, the collections differed considerably in their dominant species. Furthermore, comparison of Hyperiidea from various parts within the investigated area of the South Pacific gyre also reflected differences in dominant species. The degree of these mesoscale spatial differences was comparable to that among the central regions of the northern and southern anticyclonic gyres.     

Indoor and outdoor household dust contamination in Cincinnati, Ohio, USA

Despite some progress in reducing the average lead level in the USA, the streets of Cincinnati, Ohio, are still contaminated by heavy metals. High levels of heavy metals will have significant unequivocal ecological impacts and pose a potential health hazard. This study evaluates the level of heavy- metal contamination in household dust and examines its relationships with the external environment. Samples of outdoor and indoor dust were collected from middle-income residential homes in the Greater Cincinnati Metropolitan District and the metal content was analysed by inductively coupled plasma atomic emission spectrophotometry. Results showed that the mean levels of lead in outdoor and indoor dusts are 650 g g-1 and 377 g g-1 and the copper levels are 253 g g-1 and 510 g g-1, respectively. The median levels are 156 g g-1 and 139 g g-1 for outdoor and indoor lead dusts and 35 g g-1 and 124 g g-1 for outdoor and indoor copper dusts. The degree of contamination may be ascribable to the age of the dwelling unit and the neighbourhood, the time when the unit was last painted, the presence of pets and the type of space heating. In addition, car exhausts seems to be a possible source of contamination.     

Growth and spatial distribution of Cassidulus mitis (Echinodermata: Echinoidea) on a sandy beach in Southeastern Brazil

Using a hand dredge, a population of Cassidulus mitis Krau, 1954 was sampled monthly from February 1986 to January 1987 at 15 stations offshore from Vermelha Beach (22°5718 S; 43°948 W), in water depths ranging from 0 to 6 m. The sex ratio indicated a slight numerical dominance of females for adults and a larger numerical female dominance for juveniles. A von Bertalanffy growth curve was estimated as L=71.00 (1-e^(-0.390t)), where L=length (mm) and t=time (yr). The instantaneous natural mortality rate (M) was estimated as 0.812. The population occupies a zone parallel to the beach, and displays a spatially aggregated pattern, with higher densities in areas characterized by coarse and very well sorted sand containing low amounts of organic matter.     

Normoxic and anoxic energy metabolism of the southern oyster drillThais haemastoma during salinity acclimation

The energetic cost associated with salinity acclimation was determined in the marine gastropodThais haemastoma by direct calorimetry under normoxic and anoxic conditions. Snails were collected from Caminada Pass near Grand Isle, Louisiana (Longitude 90°2W; Latitude 29°2N) in September 1987. Metabolic heat flux of snails acclimated to and measured at 10 or 30 S was similar at 15.06 or 16.39 J g^–1 dry wt h^–1, respectively, (corresponding to 0.76 or 0.83 ml O₂ g^–1 dry flesh wt h^–1) under normoxic conditions, and 2.39 or 2.53 J g^–1 dry wt h^–1 under anoxic conditions. Inter-individual variability was high, obscuring the effect of salinity gradient on heat flux. When standardized to the pre-transfer control level of each individual under anoxic conditions, a significant increase (55%) of energy expenditure was observed for snails transferred to hyperosmotic conditions. In contrast, heat flux varied insignificantly in individuals in the anoxic 30 to 10 S transfer. After transfer of individuals from 10 to 30 S under normoxic conditions, heat flux was depressed initially to 38% of the control rate, but recovered after 14 h to a higher metabolic rate (56%) than the pre-transfer control rate. After transfer of individuals from 30 to 10 S under normoxic conditions, the standardized heat flux decreased to 28% of the control rate, followed by a 20 h period of recovery to the control rate. The energy cost of intracellular hypoosmotic regulation was less than hyperosmotic regulation under anoxic conditions. The retraction of the foot ofT. haemastoma after normoxic salinity transfers did not generally correlate with the time course of metabolic heat flux.     

The effect of temperature-salinity combinations on survival and growth of juvenile Patiriella pseudoexigua (Echinodermata: Asteroidea)

Adult Patiriella pseudoexigua were collected in October 1989 from Wanlitung, Taiwan and then induced to spawn in the laboratory. Post-metamorphosed juvenile P. pseudoexigua were reared on a diet of benthic algae Navicula sp. at 25°C and salinity (34). Six weeks after metamorphosis, juvenile P. pseudoexigua at ca. 400 m in radius were reared on a diet of benthic algae Navicula sp. at different combinations of temperatures (20, 25, 30°C) and salinities (26, 30, 34) for 40 d. Both temperature and salinity had a significant effect on juvenile survival and growth. Juveniles survived best (>90%) at 25°C and 34 and grew best (to ca. 750 m in radius) at 30°C and 34. Variation in juvenile size was small immediately after metamorphosis and increased with time.     

Activity and metabolism of larval Atlantic cod (Gadus morhua) from Scotian Shelf and Newfoundland source populations

Patterns of activity and metabolism were investigated in larval Atlantic cod (Gadus morhua L.) between December 1991 and July 1992: (1) throughout larval development; (2) between two genetically discrete populations (Scotian Shelf and Newfoundland) and (3) as a function of two different culture temperatures. During the yolk-sac stage (0 to 5 d post-hatch), changes in swimming speed were not related to mass-specific metabolic rates; no portion of the mass-specific oxygen consumption could be explained by changes in activity. In the mixed feeding stage (6 to 14 d posthatch), there was a tendency for oxygen consumption to be related to changes in swimming speed. In the exogenous feeding stage (>14 d post-hatch), oxygen consumption significantly increased with swimming speed. These ontogenetic patterns of activity and metabolism were the same for larvae from the Scotian Shelf and Newfoundland populations. However, over the entire larval life and among ontogenetic stages, the metabolic cost of activity (mass-specific O₂ consumption/swimming speed) of Scotian Shelf larvae was significantly higher than that of Newfoundland larvae. When cod larvae, that had developed at 5°C, were acutely exposed to 10°C, Scotian Shelf larvae had a higher intrinsic cost of activity than Newfoundland larvae, over the entire larval life. During the exogenous feeding stage, the mean metabolic cost of activity for Newfoundland larvae raised at 10°C and tested at 10°C was significantly higher and more variable than that of larvae raised at lower temperatures. However, the metabolic cost of activity of larvae raised and tested at 10°C was not significantly different between source populations. Together these findings suggest that differences in swimming energetics reflect changing energy requirements for activity among ontogenetic stages, and reflect adaptation to regional environments among genetically discrete populations.     

Sea-water temperature and spawning behaviour in the seastar Marthasterias glacialis

The seastar Marthasterias glacialis (L.) was seen to spawn in two sea inlets, Lough Hyne (9°18W; 51°30N) and Mulroy Bay (7°42W; 55°12N), Ireland. Spawning occurred during the afternoon and early evening between 13.30 and 21.30 hrs British Summer Time (BST) on sunny days during July and August, 1978. Groups remained assembled for days prior to spawning. Solitary and grouped seastars arched themselves and released their gametes freely. Local moderate onshore winds on sunny days resulted in increases of sea temperature which often induced spawning. Males observed spawning ranged from 2.5 to 26 cm and females from 9 to 22 cm in diameter over the period 1978–1985.     

Temperature,salinity and ultraviolet irradiation effects on the growth of strains of Nitzschia ovalis

Three strains of Nitzschia ovalis Arnott grew at temperatures from 15°–36°C and at salinities from 5–40 S Optimum growth occurred at combinations of 25°, 27.5° and 30°C and 25, 30 and 35S. This estuarine benthic diatom tolerates wide salinity and temperature conditions while demonstrating resistance to ultraviolet irradiation at 350 nm.     

Identification of Amazon River water at Barbados,W. Indies,by salinity and silicate measurements

Salinity and silicate concentrations were studied at about fortnightly intervals for 21 months at a station near Barbados, W. Indies; latitude 13°15 N, longitude 59°42 W. A sensitive inverse correlation was found to exist at 5 and 25 m, but not at greater depths. Salinity near the surface varied between 33.5 and 36.0, and silicate between a little less than 1 and 4 g at/l. Low salinity water, rich in silicate, was found from February to July; salinity increased and silicate decreased from September to December. It is argued that the low salinity water at Barbados can be identified with the areas of reduced salinity found by Ryther et al. (1967) about latitude 8° to 10° N, longitude 50° to 55° W, and that this water originates from the Amazon River. Local precipitation does not seem to be a significant factor.     

Potential effects of a resuspension event on the vertical distribution of copepod eggs in the sea bed: a laboratory simulation

Adult female Acartia tonsa and Labidocera aestiva were obtained from inshore marine waters near Turkey Point, Florida (29°54.5N;84°31W) during April and May 1991. For each species, eggs spawned overnight in the laboratory were collected, mixed with sediment, and added to a plastic tube (26 to 29 cm longx5 cm diam) to yield a 2 cm-thick layer. This tube was connected to a 245 cm-long tube, seawater was added and the contents were thoroughly mixed by turning the assembly end-over-end several times. The vertical distribution of eggs in the sediments following resuspension varied according to the grain size of the sediments. For sediments of 125 m particle-diameter, 68 to 72%, and 70 to 73% of the eggs of A. tonsa and L. aestiva, respectively, occurred in the upper 4 mm.For sediments 63 to <125 m particle-diameter, 34 to 36% of the eggs of A. tonsa and L. aestiva, respectively, occurred in the upper 4 mm. For sediments of <63 m particle-diameter, egg distribution was uniform for both species throughout the 2 cm layer. The results indicate that the vertical distribution of eggs in the sea bed following a resuspension event should be highly dependent upon the grain-size composition of the sediments.     

Grazing and ingestion rates of nauplii,copepodids and adults of the marine planktonic copepod Calanus helgolandicus

The average grazing and ingestion rates of all stages of the marine planktonic copepod Calanus helgolandicus (Calanoida) from nauplius stage IV to adults were measured experimentally at 15°C in agitated cultures. The chain-forming diatom Lauderia borealis and the unarmoured dinoflagellate Gymnodinium splendens were offered as food. The food concentrations were close to natural conditions and ranged from 36 to 101 g of organic carbon per liter. The medium body weights expressed in g of organic carbon of almost all larval stages raised at 49 g C/1 were identical with the weight of the same stages caught in the Pacific Ocean off La Jolla, California, USA. In a log-log system, grazing and ingestion rates increased almost linearly with increasing body weight. Grazing rates ranged from 4 to 21 ml/day/nauplius stage IV to 286 ml to 773 ml/day/female. Ingestion rates increased from 0.2 g to 0.8 g C/day/nauplius stage IV to 18 g to 69 g C/day/female. Grazing and ingestion rates per unit body weight decreased gradually with increasing body weight. The daily ingested amount of food decreased from 292 to 481% of the body weight (g C) of nauplius stage V to 28–85% of the body weight of adult females. Grazing and ingestion performances of all stages increased with increasing particle size. Grazing rates decreased and ingestion rates increased with increasing food concentrations. The published data on food intake of the different age groups of C. helgolandicus show that the young stages of herbivorous planktonic copepods can play a major part in the consumption of phytoplankton in the sea due to their high grazing and ingestion rates.     

Thallium in marine plankton

Concentrations of thallium in phytoplankton (0.02 to 0.8 g g^–1), zooplankton (0.03 to 0.5 g g^–1) and ichthyoplankton (0.1 g g^–1) from the central Pacific were comparable , as were the atomic ratios of thallium to calcium (3x10^–6) and to potassium (1x10^–6) in those organisms. These relatively constant ratios, plus the biounlimited ocean profile of thallium, indicate that it is rapidly cycled through plankton in the same manner as potassium, its principal biogeochemical analogue. The higher atomic ratios of thallium to potassium in pelagic clays (6x10^–6) and ferromanganese nodules (4x10^–3) suggest that both biological transport processes and abiotic transport processes influence this trace element's oceanic cycle.     

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.     

Ecological investigations of the late-stage phyllosoma and puerulus larvae of the western rock lobster Panulirus longipes cygnus

The distribution and abundance of the late-stage phyllosoma larvae of Panulirus longipes cygnus George and the distribution and densities of the final larval stage, the puerulus, both in the plankton and at settlement along the coast, were investigated. A total of 3,617 late-stage phyllosoma (Stages VI to IX) and 301 puerulus larvae were caught at 187 plankton stations during the July to November periods 1974, 1975 and 1976 off the west coast of Australia between 29°00 to 32°30S and 113°30 to 115°00E. The depth range sampled was 0 to 35 m on the continental shelf and 0 to 90 m off the shelf. During onshore/offshore cruises with similar sampling effort on and off the shelf, 1,169 late-stage phyllosoma larvae were taken, of which only 9 were caught on the shelf, and these near the outer edge. A series of cruises sampling two areas beyond the shelf near 29°30 and 32°00S yielded 2448 late-stage phyllosoma, with greater densities of larvae in the northern location. The settlement of puerulus-stage larvae along the coast in the same geographical range was also greater in the north than in the south. The data from the onshore/offshore cruises showed a definite effect of moon phase on numbers of puerulus larvae caught on the shelf, with higher catches near new moon. The low numbers of puerulus larvae (usually 0, 1 or 2 individuals) caught at all stations showed that the puerulus stage is sparsely distributed in the plankton. Fewer puerulus larvae were present at the surface than at lower depths, but it was not possible to determine a depth preference for the puerulus between 10 m and the lowest depths sampled because of the low catch numbers. No relationships were found between puerulus larvae density and surface-water temperature, salinity, or plankton biomass at each station. Data on the larval distributions indicate that, near the end of their planktonic existence, the majority of the late-stage phyllosoma larvae of P. longipes cygnus are not carried onto the shelf, where mixing of oceanic and continental shelf waters occurs only on the outer third, but are transported southward by oceanic circulation beyond the shelf. The puerulus moults from the last phyllosoma stage beyond the shelf and completes the larval cycle by swimming across the shelf and settling in the shallow reef areas.     

Algal overgrowth of alcyonacean soft corals

Colonies of the soft coral Lobophytum pauciflorum (Ehrenberg, 1834) (Coelenterata: Octocorallia: Alcyonacea: Alcyoniidae), some of which were heavily overgrown by the algae Ceranium flaccidum (Kuetzing) Ardissone and Enteromorpha sp., and other minor epizoites, were collected at Taylor Reef (17°50S; 146°35E) in the Great Barrier Reef. Overgrown colonies contained the diterpene 2-epi-sarcophytoxide as the major secondary metabolite, while conspecific colonies with clean polyparies contained two diterpenes in approximately equal amounts: 14-hydroxycembra-1,3,7,11-tetraene and 15-hydroxycembra-1,3,7,11-tetraene. By contrast, twenty conspecific pairs of overgrown and clean colonies of other alcyoniid soft corals collected from Pelorus Channel, Palm Island Group (18°34S; 146°29E), showed no chemical differences within in the pairs. Cultures of a common species of Ceramium [C. codii (Richards) Mazoyer] were incubated with different concentrations of nine soft-coral-derived diterpenes and significant algal growth inhibition was observed in many cases. It appears that terpenoids from soft coral may contribute to the lack of epizoic organisms on soft-coral polyparies.     

Descriptions and durations of premolt setal stages in female Dungeness crabs,<Emphasis Type="Italic"> Cancer magister</Emphasis>

For crustaceans with a well-defined annual molting season, such as adult female Dungeness crabs (Cancer magister Dana), setal molt staging can, in principle, be used to predict molting destiny of individual crabs. Size-specific predictions of molting probability could, in turn, be useful for estimating mortalities due to molting. Female Dungeness crabs were collected January–March 1997 at depths of 10–30 m off the California coast, USA (41°N). Intermolt stage A₁–C₄ and premolt stages D₀, D₁, D₁, D₁ and D₂ were described based on features of the branchial epipod. Laboratory experiments suggested that stage D₁ was the earliest stage beyond which eventual molting was inevitable so that molting destiny could be determined. Estimated mean number of days from the beginning of stage D₁ to molting was 85. Estimated individual stage durations, based on laboratory experiments, were 24, 51, –4, 18, and 20 days, respectively, for stages D₀, D₁, D₁, D₁, and >D₂. The estimated –4 days for stage D₁ suggests that this stage must be very brief and raises a question of its utility in designation of molt stages. Molt staging of three field samples, 300–600 crabs in each, collected prior to the 1997 annual molting season, indicated an increase in the size and frequency of crabs staged D₁ or later as the time to molt approached, although crabs of 150 mm carapace width and larger showed few signs of molt preparation. Because the duration of the molting season (approximately 120 days) for adult female C. magister in northern California exceeds the estimated maximum duration of reliable prediction of molting destiny (85 days), it does not appear that molt staging can be used to predict molting destiny in this population. However, the procedures that we have used in this paper for application to female C. magister might be used with success for other crustaceans if the duration of stages D₁ to molting exceeds the duration of the molting season, and furthermore may be used for describing temporal molting trends.Communicated by J.P. Grassle, New Brunswick     

Influence of three sediment types on copper toxicity to the polychaete Neanthes arenaceodentata

Adult male Neanthes arenaceodentata were exposed to 0.10±0.015 mg l^-1 copper in the seawater of a continuous-flow bioassay system in the presence of a sand, a mud, a mixture of the sand and mud, and no sediment, to assess the influence of sediment type on Cu-induced mortality. The sediment type did influence mortality. The time to 50% mortality was 7.8 days without sediment, 36.5 days with sand, 54.5 days with the mixture, and 50.0 days with mud. There was no threshold Cu body burden that caused death. The mean Cu concentration per gram of N. arenaceodentata (24 h after death) without sediment was 270 g, in sand 994 g, in the mixture 1047 g, and in mud 1464 g. The differences in the toxic responses are discussed.