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.     

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.     

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.     

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.     

Photoacclimation of Ulva rotundata (Chlorophyta) under natural irradiance

Two vegetative clones (designated 11/85 and 7/86 in accordance with month/year of collection) of the green macroalga Ulva rotundata were collected in the vicinity of Beaufort, North Carolina, USA. Each was grown in an outdoor continuous-flow system in summer (20°C) of 1986 and late winter (10° to 17°C) of 1987, in irradiances ranging from 9 to 100% of full sunlight, with and without NH ₄ ⁺ enrichment. Continuous enrichment of influent estuarine water (dissolved inorganic nitrogen 2 M, N:P5) to 8–12 M NH ₄ ⁺ had only a slight effect on growth rate. Temperature changes of 2 to 3°C had a much greater effect. Prolonged exposure to a given daily irradiance resulted in acclimation, exposure to a given daily irradiance resulted in acclimation, indicated by faster growth of conditioned plants relative to those transferred from a different irradiance. Most of the difference in growth rates between transferred and control plants was attributed to differences in thallus absorptance. Growth was photoinhibited above 40% sunlight at temperatures below 15°C, but not above 20°C. Following interday irradiance transfers, thallus percent dry weight changed in a manner that suggests different response times for photosynthesis and cell division.     

Environmental influence on the locomotor activity rhythm of the sand-shore amphipod Talorchestia deshayesi

The precision and persistence of the nocturnal, surface locomotor activity rhythm of the sand-beach amphipod Talorchestia deshayesi is described. The rhythm is expressed as a circadian activity period with no evidence of a circa-tidal component associated with the time of high tide. The rhythm is light-sensitive and entrainment occurs in response to changes in the time of an experimentally simulated dusk transition. Locomotor activity is initiated at the end of the dusk transition with cessation always occurring prior to dawn. The point of activity initiation is taken to be the position of a synchronizing cue controlling entrainment. The cue appears to be an absolute irradiance level of approximately 1.0 to 2.0×10^-4 W m^-2     

Nutrient enrichment and the ultrastructure of zooxanthellae from the giant clam Tridacna maxima

The separate and combined effects of ammonium (10M) and phosphate (2M) on the ultrastructure of zooxanthellae (Symbiodinium sp.) from giant clams, Tridacna maxima, were examined in the field. Nitrogen addition significantly changed the ultrastructure of the zooxanthellae inhabiting the clams. After 9 mo exposure, the cross-sectional area of zooxanthellae from N-treated clams was significantly lower than that from other treatments [N=39.3 m²; C=47.9 m²; P=43.2m²; N+P=44.5 m²; (P=0.001)]. There was also a significant decrease in the size of starch bodies, especially around the pyrenoid of the zooxanthellae from N and N+P treatments [N=1.2 m²; C=2.0 m²; P=1.8 m²; N+P=1.2 m²; (P=2.08E-11)]. This presumably occurs as a result of the mobilization of organic carbon stores in response to stimulated amino acid synthesis under enriched nutrient conditions. These data strongly suggest that the symbiotic zooxanthellae of clams are limited to some extent by the availability of inorganic nitrogen, and that relatively minor changes to the nutrient loading of the water column can have substantial effects on the biochemistry of symbioses such as that which exists between clams and zooxanthellae.     

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.     

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     

Stable isotope and biochemical fractionation in the marine pelagic food chain: the jellyfish Pelagia noctiluca and net zooplankton

In our field study we analyzed the C and H isotopic and biochemical (C, N, P, protein, lipid, carbohydrate) composition of the jellyfish Pelagia noctiluca (collected from the Gulf of Trieste in 1985 to 1986) and its presumed diet-net zooplankton. The mean ¹³C (-18.8) and D (-58.4) ratios of P. noctiluca showed enrichment in heavy isotopes relative to net zooplankton (2 for carbon and 30 for hydrogen). Both the jellyfish and net zooplankton were characterized by a linear correlation between ¹³C and D. C. N, P, protein, lipid, and carbohydrate contents of P. noctiluca were low on a dry weight basis as compared to net zooplankton. Significantly lower C:N and C:P ratios were found in jellyfish indicating a greater loss of carbon relative to nitrogen and phosphorus along the passage to a higher trophic level. Isotopic and biochemical evidence indicate that, though collected in nearshore waters, P. noctiluca depended on autochthonous marine organic matter.     

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.     

Dependence of consumers on macroalgal (Laminaria solidungula) carbon in an arctic kelp community: δ13C evidence

Stable carbon isotope measurements (¹³C) were used to assess the importance of kelp carbon (-13.6 to-16.5) versus phytoplankton carbon (-25.5 to-26.5) to resident fauna of an isolated kelp bed community on Alaska's north arctic coast from 1979 to 1983. The predominant kelp, Laminaria solidungula, showed some seasonal variation in ¹³C which was correlated with changes in the carbon content of the tissue. Animals that showed the greatest assimilation of kelp carbon (>=50%) included macroalgal herbivores (gastropods and chitons,-16.9 to-18.2), a nonselective suspension feeder (an ascidian,-19.0) and a predatory gastropod (-17.6). Animals that showed the least incorporation of kelp carbon into body tissues (<=7%) included selective suspension-feeders (hydroids, soft corals and bryozoans,-22.8 to-25.1). Sponges, and polychaete, gastropod and crustacean omnivores exhibited an intermediate dependence on kelp carbon (15 to 40%). Within some taxonomic groups, species exhibited a broad range in isotopic composition which was related to differences in feeding strategies. In the polychaete group alone, ¹³C values identified four major feeding habits: deposit-feeders (-18.0), omnivores (-20.4), predators (-22.2) and microalgal herbivores (-23.0). Distinct seasonal changes in the ¹³C values of several animals indicated an increased dependence on kelp carbon during the dark winter period when phytoplankton were absent. Up to 50% of the body carbon of mysid crustaceans, which are key prey species for birds, fishes and marine mammals, was composed of carbon derived from kelp detritus during the ice-covered period.     

Bowhead whale (Balaena mysticetus) growth and feeding as estimated by δ13C techniques

Tissue ¹³C of bowhead whale, Balaena mysticetus, varies seasonally in response to geographic variations in the ¹³C of prey organisms consumed along the annual migratory route between the Bering, Chukchi and Beaufort Seas. Seasonal changes in body ¹³C of whales taken in 1986 from Alaskan waters provide a means of estimating energy intake from the different habitats in which the whales feed. Adult bowheads do not show significant seasonal shifts in the ¹³C of muscle and visceral fat. Their enrichment in ¹³C relative to subadult whales suggests that they acquire most of their food from fall and winter feeding or from unsampled parts of the summer range where zooplankton are enriched in ¹³C. Young individuals however, undergo marked seasonal shifts indicating that they feed heavily both in the summer and autumn or winter. Oscillations in ¹³C along the length of the baleen also provide a measure of age. Baleen growth rates decline as the whales age and provide a means of correcting for wear loss and allow aging of individuals less than 12 yr old. Although body length is a poor indicator of age in young bowhead whales, baleen length is closely correlated. Growth rates of bowheads after Year 1 are slow ( 0.4m yr^-1) and up to 20 yr are required to reach the assumed length of sexual maturity at 13 to 14m.     

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.     

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.     

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.     

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.     

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.     

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.     

Effects of salinity fluctuation on the hemolymph composition of the blue crab Callinectes sapidus

The hemolymph of the blue crab Callinectes sapidus was hyperosmotic during 20-10-20 S and 30-10-30 S diurnal cycles. The hemolymph became isosmotic at 26 S and hyposmotic at 28 S in the 10-30-10 S diurnal cycle. Hemolymph Na⁺ was hyperionic to seawater throughout all cycles. Hemolymph Cl^- was hyperionic below 24 S and either isionic or hypoionic from 24 to 30 S. Hemolymph K⁺ concentrations were hyperionic below 26 S and either isionic or hypoionic from 26 to 30 S. Hemolymph Mg⁺⁺ values were hypoionic over the experimental salinity range (10 to 30). Hemolymph ninhydrin-positive substances (NPS) levels were directly related to ambient salinity.