Night irradiance and synchronization of lunar release of planula larvae in the reef coral Pocillopora damicornis

Pocillopora damicornis (Linnaeus), which is known to release planula larvae on a monthly cycle, was grown in full daytime solar irradiance, but with four treatments of night irradiance: (1) natural night irradiance, (2) shifted-phase (total darkness during nights of full moon with artificial irradiance at lunar intensity on nights of new moon), (3) constant full moon (full lunar irradiance every night), and (4) constant new moon (total darkness every night). The reproductive cycle of the corals held in the shifted-phase treatment moved out of synchrony with the cycle of corals exposed to a natural lunar cycle of night irradiance. Two previously described types of P. damicornis were tested. The Type Y normally start releasing larvae at full moon, with peak production at third quarter. In the shifted-phase treatment they began releasing planulae at new moon (artificial full moon), with peak production at first quarter. The Type B corals, that normally start releasing planulae at new moon with peak production at first quarter, began to release planulae at full moon (artificial new moon), with peak production at third quarter. Populations of corals grown either in the constant full moon or constant new moon treatment quickly lost synchronization of monthly larva production, although production of planulae continued. Thus spawning is synchronized by night irradiance.Contribution No. 702 of the Hawaii Institute of Marine Biology     

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.     

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.     

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.     

Aqua regia extractable trace elements in surface soils of venezuela

Surface soils (0–15 cm) were sampled at 10–20 km intervals along two transects in Venezuela. One (1162 km, 70 samples) ran west to east parallel with the Caribbean coastline, the other (920 km, 92 samples) ran south to north from the frontier with Brazil to the Caribbean shore. Sampling took place in both a wet and a dry season. Trace metals were extracted from dried, sieved (<2 mm) soil with boiling aqua regia followed by analysis by ICP or flame AAS. Metal values did not differ significantly between the two seasons and dates were averaged. Geometric mean values for the west–east transect were: Cr=41.5, Cu 17.9, Cs 3.6, Li=13.9, Mn=294, Ni=21.3, Pb=17.4, Sr=39.4, V=60.4 and Zn = 83.7g g^–1, respectively. Similarly, for the south–north transect Cr=21.3, Cu=4.3, Cs=1.1, Li=2.0, Mn=55.7, Ni=4.4, Pb=6.1, Sr=13.3, V=28.2 and Zn=16.7g g^–1, respectively. A classification of samples by lithology showed surface soil composition to be related to rock composition. Metal values were low in the soils in the south of the country, in the Guyana highlands (Gran Sabana). Low Zn contents were prevalent. Lead contents were affected by roadside fallout from vehicles using leaded petrol except that high Pb contents of soils in the Gran Sabana were of more complex origin.     

Feeding,growth and bioluminescence of the heterotrophic dinoflagellate Protoperidinium huberi

Feeding, growth and bioluminescence of the thecate heterotrophic dinoflagellate Protoperidinium huberi were measured as a function of food concentration for laboratory cultures grown on the diatom Ditylum brightwellii. Ingestion of food increased with food concentration. Maximum ingestion rates were measured at food concentrations of 600 g C l^-1 and were 0.7 g C individual^-1 h^-1 (1.8 D. brightwelli cells individual^-1 h^-1). Clearance rates decreased asymptotically with increasing food concentration. Maximum clearance rates at low food concentration were ca. 23 l ind^-1 h^-1, which corresponds to a volume-specific clearance rate of 5.9x10⁵ h^-1. Cell size of P huberi was highly variable, with a mean diameter of 42 m, but no clear relationship between cell size and food concentration was evident. Specific growth rates increased with food concentration until maximum growth rates of 0.7 d^-1 were reached at a food concentration of 400 g C l^-1 (1000 cells ml^-1). Food concentrations as low as 10 g C l^-1 of D. brightwellii (25 cells ml^-1) were able to support growth of P. huberi. The bioluminescence of P. huberi varied with its nutritional condition and growth rate. Cells held without food lost their bioluminescence capacity in a matter of days. P. huberi raised at different food concentrations showed increased bioluminescence capacity, up to food concentration that supported maximum growth rates. The bioluminescence of P. huberi varied over a diel cycle, and these rhythmic changes persisted during 48 h of continuous darkness, indicating that the rhythm was under endogenous control.     

Respiration et excrétion azotée du zooplancton. I. Evaluation des niveaux métaboliques de quelques espèces de Méditerranée occidentale

The effects of sublethal concentrations of mercury in combination with stressful temperature-salinity regimes were considered for larval development of the fiddler crab Uca pugilator (Bosc.). Control organisms were compared to those treated with 1.8 ppb Hg for the following suboptimal regimes: 30°C, 30 S; 30°C, 20 S; 20°C, 30 S, and 20°C, 20 S. As physiological indicators of larval response, the survival rate, the O₂ consumption rate, and phototactic response were measured, following either acute 24 h doses of Hg, or chronic rearing in Hg. All response parameters were modified in larvae maintained under the suboptimal conditions; mercury compounded the effects.Supported by Grant No. 18080 FYI from the Environmental Protection Agency.     

Particulate organic carbon and nitrogen in the adjacent seas of the Pacific Ocean

Particulate organic carbon (POC) and nitrogen in sea water were measured in samples collected in the adjacent seas of the Pacific Ocean during the cruises of T. S. Oshoro-Maru (1969, 1970) and the R. V. Hakuho-Maru (KH-70-4, KH-72-1). High values were obtained in the northern North Pacific and the Bering Sea, the concentration of particulate carbon in the upper 50-m layer ranged from 35 to 550 g Cl^-1. In the deep waters of these area, values above 50 g Cl^-1 were frequently observed. The lowest values in the surface layer and deeper layers were obtained in the Japan Sea (23 gCl^-1) and in the South China Sea (7 g Cl^-1) respectively. A consistent minimum was located in the intermediate waters (100–400 m) throughout the entire region studied. Variation with depth was generally irregular with marked peak values in different layers. The POC distribution consited of these peak values and a relatively uniform background concentration. These background values slightly decreased with increasing depth and were different locally. Correlation analysis between carbon concentration and apparent oxygen utilization (AOU) of ambient water for the samples in the Japan Sea and the Sulu Sea showed that there was no systematic decrease of particulate carbon with increasing AOU. In these areas, the carbon concentration scattered in the higher AOU domain ranged from 10–100 g Cl^-1. These observations support the conception that downward transport of particulate matter from the overlying surface layer in the adjacent seas of the Pacific Ocean may be fairly rapid.     

Soil Lead at Elementary Public Schools: Comparison Between School Properties and Residential Neighbourhoods of New Orleans

Soil studies, conducted in Maryland, Minnesota and Louisiana, have described the urban pattern of lead contamination. They have shown that the highest amounts of lead cluster within the interior of the largest cities. The results of the New Orleans urban patterns of distribution of soil lead provided the basis for further study. The hypothesis was tested that elementary school properties have the same pattern of soil lead contamination as their neighbouring residential communities. Thirty New Orleans Public Elementary Schools were selected for this study. Surface samples (2.5cm or 1 inch depth) were collected from playgrounds and next to entrances of each school. Results showed that soil lead on school properties follows the same relative contamination patterns (pvalue10^–5) as soil lead on residential properties of neighbouring communities. Schools however, have significantly lower lead contamination than the neighbouring residential properties. Innercity school properties present a higher risk of soil lead exposure than mid and outercity schools. Soils next to innercity school entrances showed the highest lead, with 18.5% having concentrations over 400gg^–1. Systematic landscaping around the school entrances would significantly reduce the hazard from lead dust contaminated soils.     

Growth of the Atlantic surfclam,Spisula solidissima,from Georges Bank to the Delmarva Peninsula,USA

Age/shell length data for offshore surfclam, Spisula solidissima (Dillwyn, 1817), populations were used to estimate the parameters of the von Bertalanffy growth model by time period and region, from Georges Bank in the north to the Delmarva Peninsula in the south. Randomization tests were used to compare curves. We tested the a priori hypothesis that growth curves would change over time in the south (i.e., New Jersey and Delmarva) but remain constant in the north (i.e., Long Island and South New England). This hypothesis was proposed because surfclam population structure in the south had been altered by the hypoxic event of 1976, and possibly by intense, long-term commercial harvesting. Northern regions, unaffected by these factors, served as natural controls. Based on a comparison of data collected in 1980 with pooled data from 1989 and 1992, the hypothesis was supported. Both the growth coefficient (k) and maximum shell length (L ) declined between two time periods in the two southern regions, while during the same time interval, no change occurred in the two northern regions. Differences in growth between regions were often statistically significant. For example, compared with the southern regions, the growth coefficient on Georges Bank was larger, and those clams attained a smaller maximum length. In a comparison of adjacent regions from Delmarva to S. New England, k increased from south to north. This could imply faster growth in cooler water, as well as no relationship between growth and primary productivity. Alternatively, size-selective mortality, imposed by the commercial fishery, was discussed as a mechanism that might account for this unexpected pattern.     

Physiological ecology of picoplankton in the North Sea

The distribution of cyanobacteria in the surface waters of the North Sea was measured during July 1987. Numbers of cyanobacteria ranged from 2.5x10⁶ to 1.7x10⁸ cells 1^-1. In the majority of stations, cyanobacterial numbers were highest in the near-surface water and a subsurface maximum was found at only one station. The distribution of ¹⁴C among the end-products of photosynthesis was determined for picoplankton (<1 m) and other phytoplankton >1 m throughout the North Sea. The majority of label was found in the protein fraction of both picoplankton and >1 m phytoplankton; incorporation into lipids and polysaccharides plus nucleic acids was much lower. We interpret the large incorporation into protein to be a consequence of nutrient limitation of these natural assemblages. Photosynthetic parameters of the two size fractions were also determined. Assimilation number (P _m ^B ) and initial slope were greater for the picoplankton fraction than for phytoplankton >1 m but there was no evidence of significant photoinhibition of either fraction at irradiances up to 1 000 E m^-2 s^-1.     

Mytilus edulis planulatus: an “integrator” of cadmium pollution?

Mussels, Mytilus edulis planulatus, were collected from Port Phillip Bay, Victoria, Australia, in February 1984, to test the assumption that they are integrators of cadmium pollution. Groups of mussels were subjected to the same average dose of cadmium (21 g l^-1), administered according to different dosing regimes over 4 wk (Regimes 1, 2, 3, 5); other groups received twice the average dose (42 g l^-1) in half the time (Regime 4). During each regime, the mussels were exposed to the different cadmium concentrations for one week at each concentration. Nominally, the regimes were: (1) 36 g (Wk 1) to 26 g (Wk 2) to 16 g (Wk 3) to 6 g (Wk 4) Cd l^-1; (2) 6 to 16 to 26 to 36 g Cd l^-1; (3) 21 to 21 to 21 to 21 g Cd l^-1; (4) 42 to 42 g Cd l^-1; (5) 42 to 42 g Cd l^-1 to background (<0.5 g) to background. Differences in cadmium accumulation by mussels from Regimes 1 and 4 were not statistically significant, nor were differences in accumulation between mussels from Regimes 2 and 3. However, mussels from Regimes 1 and 4 had accumulated significantly more cadmium than had mussels from Regimes 2 and 3. Accumulation by mussels from Regime 5 was not significantly different from that by mussels from any of the other regimes. These results suggest that, at least for cadmium, the assumption that mussels are integrators of pollution should be treated with caution. They also have implications with regard to the quantitative biological monitoring of pollution. For example, even in a carefully controlled monitoring program, using mussels of standard size and condition, significant differences in cadmium content between mussels need not indicate exposure to different levels of contamination. Rather, these differences could reflect differences in the regime by which the contamination was received.     

Primary production in Dumbell Bay in the Arctic Ocean

Photosynthesis, chlorophyll, inorganic nutrients, and related factors were measured throughout a productive season in a small coastal inlet of the Arctic Ocean. Significant production was confined to 5 m for a very limited time period beacause of both light and nutrient limitations. Maximum chlorophyll was 8.2 mg Chl a m^-3 and maximum gross and net photosynthesis rates were 830 and 550 mg C m^-2 d^-1. Annual gross and net photosynthesis is estimated at about 12 and 9 g C m^-2 respectively. The effect of light stimulation on assimilation is described, sources of coastal zone nutrient enrichment are considered, and discrepancies between gross and net photosynthesis are discussed with reference to the growth characteristics of the phytoplankton population.Bigelow Laboratory for Ocean Sciences. Contribution No. 76008     

Effect of temperature and food on the heart beat,ventilation rate and oxygen uptake of Mytilus edulis

The heart beat, ventilation rate and oxygen uptake of Mytilus edulis L. were measured simultaneously, in response to changes in temperature and food level. There was no thermal acclimation of heart-beat frequency or amplitude to temperatures from 5° to 25°C. Oxygen consumption and ventilation rate acclimated to 10°, 15° and 20°C, but not to 25°C. Starvation reduced the rate of oxygen uptake and heart-beat frequency to a standard level and, in response to food, the ventilation rate and oxygen consumption immediately increased to an active level. Feeding was maintained after the initiation of active metabolism, and during the following 10 days the heart-beat frequency gradually increased to the level characteristic of fed individuals. There was no direct correlation between the rate of oxygen consumption and heart rate, and an apparent absence of a close nervous coupling between ventilation rate and heart rate in M. edulis.     

Environmental Accumulation of Airborne Fluorides in Romania

The nature and extent of pollution from an aluminium smelter and a fertiliser factory in Romania were studied. These are large industrial complexes, and both types of industry are known to release fluorides into the atmosphere. In grass samples collected from around the aluminium smelter, the maximum fluoride levels were found to be 4023mgkg^–1 and 162mgkg^–1 in unwashed and washed grass samples respectively, and 89mgkg^–1 in soils. For the fertiliser factory, the maximum levels in washed grasses were found to be 207mgkg^–1, and 11mgkg^–1 in the soils. In both locations, these maximum values were obtained in samples collected from within 200m of the factory limits, and compare with regional background levels of less than 10mgkg^–1 for grasses and 2mgkg^–1 for soils. The high fluoride levels of fluoride in the grasses are sufficient to give cause for concern for the effects that these could have on the local population and on grazing animals.     

Genetic variation and biochemical systematics in the marine bryozoan Alcyonidium mytili

For many years the taxonomic position of the marine ctenostome bryozoan Alcyonidium mytili Dalyell (1848) has been in doubt, with some authorities regarding it as being conspecific with A. polyoum (Hassall). We have set out to resolve this problem using enzyme electrophoresis to examine the genetics of the population structure in the two species. The results show beyond reasonable doubt that sympatric populations of the two species are indeed from quite separate and non-interbreeding gene pools. An examination of various allopatric populations shows a new species of A. mytili to exist sympatrically with the other at Langstone Harbour, Hampshire, England. This species can be readily distinguished on morphological as well as genetic ground. Samples of A. mytili from Guernsey also show substantial genetic differences from other populations examined. It is tentatively concluded that this population also represents a separate gene pool and consequently should be recognised as a third species of A. mytili.     

Nutrition studies in the nauplius larva of Calanus pacificus (Copepoda: Calanoida)

Nauplii of Calanus pacificus were raised on a mixture of algae. Details of the mouth-parts, such as denticles, labial palps and lobes, setations and structure of the masticatory teeth were examined by scanning electron microscopy (SEM). Under the experimental conditions (15°C and 300 gC l^-1), exponential growth coefficients for the period Nauplii II–VI were 0.179 for carbon and 0.228 for nitrogen. C:N ratios dropping from 5.1 to 4.7. Growth was isochronous, each stage lasting 1.5 days. Respiratory losses were 15 to 19.6% of body carbon daily. Nauplii raised on a given alga showed higher rates of ingestion in the presence of this food, compared to nauplii switched to other algae. Minimal threshold concentrations for feeding were found, depending on the size of the food offered and ranging from 5.8 gC I^-1 for Lauderia borealis (28.7 m spherical diameter) to 47.1 gC 1^-1 for Chlamydomonas sp. (11.0 m). Unlike the Copepodite I stage, Nauplii II–VI larvae were not able to ingest small cells such as Isochrysis galbana (4.3 m), or very large ones such as Ditylum brightwellii (47.5 m) at more than maintenance rations. Below the critical concentration for maximal feeding, ingestion was clearly dependent on size of the cells offered, but the size-dependent relationship was different for diatoms and non-diatoms. Filtering rates increased from a threshold concentration to a maximal rate at about 50 gC 1^-1, and decreased at higher concentrations. Critical concentrations ranged from 125 gC 1^-1 for L. borealis to 1000 gC 1^-1 for Chlamydomonas sp. Maximal daily rations ranged between 100 and 150% of body carbon.     

Carbon fixation in marine phytoplankton: carboxylase activities and stable carbon-isotope ratios; physiological and paleoclimatological aspects

We measured the activity of three carboxylases: RuBP carboxylase, PEP carboxylase and PEP carboxykinase of marine phytoplankton species in culture and in natural communities. Activities of the three carboxylases were measured simultaneously with stable carbon-isotope ratios. The enzymatic activities have been used to estimate the importance of carboxylation and its impact on the ¹³C:¹²C ratio (expressed as ¹³C). The marine phytoplankton species in culture were Fragilariopsis kerguelensis, Nitzschia turgiduloides, Skeletonema costatum, Phaeodactylum tricornutum, Isochrysis galbana, Dunaliella marina, and Prorocentrum micans, and the field samples were collected from different depths off the coast of Portugal (August/September, 1981). Our results indicate that, as in terrestrial plants, the ¹³C value is a good indicator of the extent of carboxylation. RuBP carboxylase activity was always predominant, whereas the ¹³C value never reached values typical of the C₄ pathway. The carboxylases could be PEP carboxylase (in dinoflagellates) or PEP carboxykinase (in diatoms). carboxylation increased at the end of the exponential growth phase in a diatom culture and with increased biomass in natural samples. We interpret these increases as an adaptative response mechanism to poor environmental conditions, especially to low light intensity.     

Compositional topography of melon and spermaceti organ lipids in the pygmy sperm whale Kogia breviceps: Implications for echolocation

The forehead of the pygmy sperm whale Kogia breviceps contains a large melon of fatty tissue in front of a small, fat-filled, cornucopia-shaped spermaceti organ. This unique anatomical structure may possibly play an acoustical role in the whale's echolocation system, similar to the fatty melon sound lens postulated for dolphins. To better understand its function, we have studied the compositional topography of the K. breviceps melon and spermaceti organ lipids. The fatty head tissues of an adult K. breviceps were serially sectioned into 9 transverse slices. Appropriate tissue samples were cut from every other slice, and analyzed for % lipid and lipid class composition. Wax esters and triglycerides were the only major lipids present; their average carbon number in each sample was determined by gas-liquid chromatography (GLC). Our topographical analyses of K. breviceps melon indicate 3 regions of distinctive lipid composition: a fat-poor melon exterior, an outer melon of medium fat content having % triglyceride>% wax ester, and a fat-rich inner melon having % wax ester>% triclyceride. The spermaceti organ contains a fat-rich core of very high wax-ester content (84 to 99%), surrounded by a fat-poor case. Average carbon numbers of both wax esters and triglycerides were lowest in the inner melon and the spermaceti organ. At the rear of the spermaceti organ lies the museau de singe, an apparent sound generator. The lipid topography data plus anatomical and acoustical considerations suggest that the K. breviceps melon/spermaceti organ system may function as an acoustical transducer, directing and refracting sound waves from this source for the purpose of echolocation.     

Effects of salinity on fasted rainbow trout,Salmo gairdneri

Rainbow trout (Salmo gairdneri Richardson) which had been maintained for 120 days in salinities of fresh water, 7.5, 15.0 and 32.5 at 10°C were fasted for up to 48 days under these same environmental conditions. Live weight loss between Days 7 and 48 of starvation could be described by a straight line, as could the decrease in condition factor . Trout maintained in 32.5% S showed a significantly greater weight loss than those in salinities of 15.0 and below. Muscle water content increased slightly during fasting in fresh water, 7.5 and 15.0 S. In 32.5 S, however, muscle water fell significantly between Days 19 and 37. Liver water content also increased slightly during fasting, except in 32.5 S, where water content again decreased between Days 19 and 37. The volume of the gall bladder contents increased during fasting.