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.     

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 and cadmium in urban allotment and garden soils and vegetables in the United Kingdom

In order to assess the intake of lead and cadmium by consumers of home grown vegetables in urban areas, replicated experimental plots of uniform size, comprising summer and winter crops, were established in 94 gardens and allotments in nine towns and cities in England.The geometric mean lead and cadmium concentrations for the soils (n = 94) were 217 g g^–1 (ranging from 27 to 1,676 g g^–1) and 0.53 g g^–1 (<0.2–5.9 g g^–1), respectively. Compared with agricultural soils, the garden and allotment soils contained elevated levels of lead but not cadmium.Lead concentrations in the vegetables ranged from <0.25 g g^–1 to 16.7 g g^–1 dry weight and cadmium concentrations ranged from <0.025 g g^–1 to 10.4 g g^–1 dry weight. Lead concentrations were higher than reported background levels, although <1% exceeded the statutory limit for saleable food in the UK (1 g g^–1 fresh weight). Cadmium concentrations were generally similar to background levels.     

Le système assimilation-régénération des sels nutritifs dans les eaux superficielles de l'océan Austral

Low primary-productivity levels in high-nutrient environments of the Southern Ocean are not yet well understood. An accurate knowledge of nutrient assimilation by phytoplankton, at the base of the pelagic food-web, therefore appears to be essential. A study of the mesoscale hydrological structure and chemical observations in the upper layers of the Indian sector of the Antarctic Ocean (Cruise MD-25 FIBEX of M.S. Marion Dufresne, January–February 1981) permitted us to develop a method for estimating nutrient consumption by phytoplankton. After strong vertical mixing in winter, the homogeneous Antarctic Surface Water (ASW) is, in summer, divided into two parts by a well-formed pycnocline. In the upper layer, corresponding approximately to the photic zone, we observed nutrient depletion resulting from photosynthetic activity, while the underlaying thermal minimum layer displayed unaltered winter characteristics, including nutrient concentrations typical of winter surface-water conditions. Taking into account the nutrient depletion in summer, we calculated the assimilation ratios for Antarctic phytoplankton as follows: ([NO ₃ ^- lower]-[NO ₃ ^- upper]):([PO ₄ upper])=N:P=11.2±2.4 and N:Si=0.27±0.05. These ratios are lower than the classical Redfield ratios (N:P=16 and N:Si=1), but are in good agreement with the elementary composition of phytoplankton samples collected during the same cruise. Moreover, they agree with previously published data on stoechiometric determinations of particulate matter in surface-water samples. Besides, in the transition layer between the lower layer and Warm Deep Water (WDW), the calculated mineralization ratios were slightly higher than the assimilation ratios: N:P=14.6 and N:Si=0.37. From these ratios, it would appear that, in these surface layers of the Southern Ocean (down to 250 m), assimilation-regeneration mechanisms operate in such a way that phosphate and silicate contents decrease much more than nitrate content during the northward drift of the surface waters. The determination of assimilation ratios taking into account the nutrient depletion of the upper layer allowed us to evaluate the carbon net-production which integrates time-space variations in the photic layer over the whole early summer period. We estimated a production rate (0.4 g C m^-2 d^-1) of the same order of magnitude as the mean value obtained by the ¹⁴C method (0.2 g C m^-2 d^-1). The theoretic silicium consumption by phytoplankton along a meridian transect, calculated using an estimated assimilation ratio of C:Si=1,85, indicates that the marked south-north decrease in silicate concentration in the Antarctic Surface Water would mainly result from biological activity. The silicate concentrations thus calculated were in good agreement with concentrations measured along a previous transect across the Southern Ocean.

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Le système assimilation-régénération des sels nutritifs dans les eaux superficielles de l'océan Austral

     

Allozyme and colour differences between two sibling species of the heteronemertean Lineus torquatus from the Sea of Japan

Brown and cherry colour morphs of the heteronemertean Lineus torquatus Coe, 1901 from the Vostok Bay of the Sea of Japan were compared using allele frequencies at 18 isozyme loci. These morphs shared no common alleles at 9 of the 18 loci. The observed genetic differences are strong evidence that the brown and cherry colour morphs, which occur sympatrically, are different species. Nei's genetic distance between these species (D=1.135) is considerably higher than typical D values for congeneric animal species. As with much previous work on nemerteans, intraspecific allozymic variability in both species was high, with mean expected heterozygosity values 0.286±0.049 and 0.159±0.051 for L. torquatus (brown) and L. torquatus (cherry) species, respectively.     

Influence of salinity on embryonic development and the distribution ofSepia officinalis in the Delta Area (South Western part of The Netherlands)

The effect of salinity on embryonic development ofSepia officinalis (cuttlefish) in the Delta Area (South Western part of The Netherlands) was investigated in 1988/1989, and compared with data concerning the distribution ofS. officinalis in the three main parts of this area: Oosterschelde, Westerschelde and Grevelingen. Embryos hatched in water collected at Yerseke (Oosterschelde), Vlissingen (Western part of the Westerschelde) and Bommenede (Grevelingen), i.e., at salinity values above 28.1, but not in water sampled at Hoedekenskerke and Hansweert (Middle and Eastern part of the Westerschelde; salinities below 22.0). Under laboratory conditions, using diluted Oosterschelde water, the highest hatching percentages ofS. officinalis were found at salinities above 29.8. Some embryos hatched at a salinity value of 26.5 but no hatching occurred at salinities below 23.9. In embryos exposed to salinity changes during late embryonic development, the developmental rate decreased at salinity values of 28.7 or less. Below 22.4 embryos with morphological malformations were found. It can be concluded that salinity is an important factor limiting the distribution ofS. officinalis in most parts of the Delta Area, with the exception of the Western part of the Westerschelde and the Grevelingen.Contribution no. 489 of the Library of the Delta Institute for Hydrobiological Research     

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.     

Do Tidal-Channel Turbulence Measurements Support k−5/3?

We seriously challenge the belief that tidal-channel data of Grant et al. support the theory for the classical energy-spectrum behavior, k ^–5/3 in the inertial subrange [where k is wave number and (k) is the one-dimensional energy-spectrum function]. The behavior revealed by our re-examination is explained in terms of a more recent theory.     

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     

Does displacement of spawning time occur in the sibling species Cerastoderma edule and C. lamarcki?

The spawning cycles of the sibling species Cerastoderma edule (L.) and C. lamarcki (Reeve) were studied in allopatric and sympatric Danish populations from 1978–1980. The results do not support earlier findings of reproductive character displacement in sympatric populations of the two species. New records of hybrid formation and intermediate forms are presented and discussed.     

Diurnal patterns in photosynthetic capacity and depth-dependent photosynthesis-irradiance relationships inSynechococcus spp. and larger phytoplankton in three water masses in the Northwest Atlantic Ocean

The photosynthetic characteristics of prokaryotic phycoerythrin-rich populations of cyanobacteriaSynechococcus spp. and larger eukaryotic algae were compared at a neritic frontal station (Pl), in a warm-core eddy (P2), and at Wilkinson's Basin (P3) during a cruise in the Northwest Atlantic Ocean in the summer of 1984.Synechococcus spp. numerically dominated the 0.6 to 1 m fraction, and to a lesser extent the 1 to 5 m size fractions, at most depths at all stations. At P2 and P3, all three size categories of phytoplankton (0.6 to 1 m, 1 to 5 m, and >5 m) exhibited similar depth-dependent chages in both the timing and amplitude of diurnal periodicities of chlorophyllbased and cell-based photosynthetic capacity. Midday maxima in photosynthesis were observed in the upper watercolumn which damped-out in all size fractions sampled just below the thermocline. For all size fractions sampled near the bottom of the euphotic zone, the highest photosynthetic capacity was observed at dawn. At all depths, theSynechococcus spp.-dominated size fractions had lower assimilation rates than larger phytoplankton size fractions. This observation takes exception with the view that there is an inverse size-dependency in algal photosynthesis. Results also indicated that the size-specific contribution to potential primary production in surface waters did not vary appreciably over the day. However, estimates of the percent contribution ofSynechococcus spp. to total primary productivity in surface waters at the neritic front were significantly higher when derived from short-term incubator measurements of photosynthetic capacity rather than from dawn-to-duskin situ measurements of carbon fixation. The discrepancy was not due to photoinhibitory effects on photosynthesis, but appeared to reflect increased selective grazing pressure onSynechococcus spp. in dawn-to-dusk samples. Low-light photoadaptation was evident in analyses of the depth-dependency ofP-I parameters (photosynthetic capacity,P _max; light-limited slope, alpha;P _max alpha,I _k ; light-intensity beyond which photoinhibition occurs,I _b ) of the > 0.6 m communities at all three stations and was attributable to stratification of the water column. There was a decrease in assimilation rates andI _k with depth that was associated with increases in light-limited rates of photosynthesis. No midday photoinhibition ofP _max orI _b was observed in any surface station. Marked photoinhibition was detected only in the chlorophyll maximum at the neritic front and below the surface mixed-layer at Wilkinson's Basin, where susceptibility to photoinhibition increased with the depth of the collected sample. The 0.6 to 1 m fraction always had lower light requirements for light-saturated photosynthesis than the > 5 m size fraction within the same sample. Saturation intensities for the 1 to 5 m and 0.6 to 1 m size fractions were more similar whenSynechococcus spp. abundances were high in the 1 to 5 m fraction. The > 5 m fraction appeared to be the prime contributor to photoinhibitory features displayed in mixed samples (> 0.6 m) taken from the chlorophyll maxima. InSynechococcus spp.-dominated 0.6 to 1 and 1 to 5 m size fractions, cellular chlorophylla content increased 50- to 100-fold with depth and could be related to increases in maximum daytime rates of cellularP _max at the base of the euphotic zone. Furthermore, the 0.6 to 1 m and > 5 m fractions sampled at the chlorophyll maximum in the warm-core eddy had lower light requirements for photosynthesis than comparable surface samples from the same station. Results suggest that photoadaptation in natural populations ofSynechococcus spp. is accomplished primarily by changing photosynthetic unit number, occuring in conjuction with other accommodations in the efficiency of photosynthetic light reactions.     

Song as an attractant for male and female European starlings,and the influence of song complexity on their response

Summary We tested the hypothesis that song attracts females and repels males in the European starling. We broadcast recorded song from speakers attached to nestboxes, while paired boxes with silent speakers served as controls. As predicted, females were attracted to the song boxes. Contrary to prediction, males were also attracted to the `song' boxes. Singing by male starlings may be costly because it attracts competitors for limited nesting sites, but the cost cannot be avoided due to the need to attract a mate. In a second experiment simple song (composed of 20 different phrase types) and complex song (40 phrase types) were played simultaneously. More males were captured at boxes where simple song was played. Song complexity may function as an indicator of male quality and be used by male starlings to assess potential competitors.     

Spatial mesoscale patterns of West Pacific picophytoplankton as analyzed by flow cytometry: their contribution to subsurface chlorophyll maxima

Vertical distributions of picophytoplankton (ppp) (<2 m) were studied by ship-board flow cytometry during two cruises in Western Pacific waters to Palau and to Australia in 1990. Weak red-fluorescing small ppp, supposed to be free-living prochlorophytes (Chisholm et al. 1988), were abundant in the area surveyed. These ppp, designated the prochlorophytes, were abundant in the surface waters (>10⁴ cells ml^-1) at the northern region (27°03N; 7°11N) in November, whereas in December at the southern tropical stations (0°23.54S; 9°20.30S; 13°50.6S), they formed subsurface maximum layers (>10⁵ cells ml^-1) on a nitracline at a depth of 3.5 to 5.4% surface irradiation. Their fluorescence intensity increased with depth below 10% surface irradiation. The prochlorophytes at a depth of 1% surface irradiation had ten times higher fluorescence than those at the surface layer. The total fluorescence intensity of the prochlorophytes accounted for 32 to 63% of the sum of the total fluorescence intensity of all fluorescing phytoplankton detected at subsurface chlorophyll maxima in the tropical area. These results suggest that distribution of the prochlorophytes is greatly affected by nitracline and by light intensity and that their chlorophyll is a major contributor to the subsurface chlorophyll maximum in the pelagic West Pacific Ocean.     

Effect of daylight variations on the energy budgets of shallow-water corals

Energy budgets were determined for small pieces (nubbins) of the coralsPocillopora damicornis, Montipora verrucosa andPorites lobata living at a water depth of 3 m on the fringing reef of Coconut Island, Kaneohe, Hawaii. The budgets were determined for three different types of day: an ideal day with no cloud and an in situ daily integrated irradiance at 3 m of 14.385 E m^–2 d^–1; a normal day with sporadic cloud cover and daily irradiance of 11.915 E m^–2 d^–1; and an overcast day with daily irradiance of 6.128 E m^–2 d^–1. On the ideal day, the energy fixed in photosynthesis was more than that required for respiration and growth of both zooxanthellae and animal components of the association, and there was a predicted loss of between 19.3 and 32.4% of the energy fixed. On a normal day, the total photosynthetic energy fixation was lower and the excess was between 12.1 and 27.9% of the energy fixed. On the overcast day, however, in bothPocillopora damicornis andPorites lobata energy expenditure exceeded photosynthetic energy fixation and the budget was in deficit. Estimates of rate of mucus secretion on an overcast day were derived and, when incorporated into the energy budget, it was predicted that all three species would have a deficit budget, necessitating the catabolism of lipid reserves. From published values for lipid storage in these species it was calculated that the reserves would last from 28 d inPocillopora damicornis to 114 d inM. verrucosa. A model is suggested in which corals draw upon their extensive lipid stores on days of sub-optimal light, replenishing the reserves again when daily light levels are high, and finally excreting the excess energy fixed, as mucus-lipid when the lipid stores are replete.     

Alternative mating tactics and the law of Diminishing Returns: The Satellite Threshold Model

Summary The mating systems of many species comprise at least 2 alternative male mating tactics — broadly termed Dominant and Satellite tactics here. But, there exists no satisfactory conceptual framework in which to explain their co-occurrence and persistence.A Dominant male's ability to copulate is a positive, but decelerating, function of either his territory's attractiveness or his own attractiveness to females. This Diminishing Returns Effect affords mating opportunities for Satellite males associated with the most attractive sites (or males). A graphical Satellite Threshold Model, analogous to the Polygyny Threshold Model (Orians 1969), is developed to predict quantitatively the presence or absence of Satellite male tactics.Five predictions of the Model are supported quantitatively by data from dragonfly and anuran social systems and, more generally, by evidence from a wide variety of species.The Model should apply both to circumstances in which males are able to alternate between tactics and the instances in which males make an irrevocable tactical decision.     

Age-structure dependence of the “specific production” in zooplankton populations

This account represents the results of investigations on the production of some zooplankton populations. For comparing different populations the index specific production (the production rate of the unit of the biomass) is used. The correlation between specific production and age-structure for some populations is described. On the basis of the growth theory of Von Bertalanffy (1938) a theoretical model which helps to explain the relation between specific production and age-structure of the population is proposed.     

Salinity tolerance of benthic estuarine diatoms as tested with a rapid polarographic measurement of photosynthesis

Measurements of net photosynthesis of benthic estuarine diatoms were made by polarographic registration of oxygen saturation. A measuring cell was constructed in which media with salinities of 2.0 to 100.7 were pumped over the algae between measurements. Diatoms from unialgal cultures and mixed populations from intertidal flats appeared to be highly tolerant of extreme salinities. During short-term exposures (20 min) the net photosynthesis of the algae did not drop below 70% of the initial values, within the salinity range 4.0 to 60.0. Prolonged exposure (up to 6 h) gave essentially the same results. Populations of benthic diatoms, sampled from field stations with mean salinities of about 30, 12, and below 5, showed only gradual differences in their tolerance of salinities between 2.0 and 33.7. Two species, Navicula arenaria and Nitzschia sigma, were cultured in media ranging in salinity from 8.0 to 45.0 and from 2.0 to 45, respectively. The tolerance to changing salinity was only slightly affected by the salinity of the medium in the preculture. The role of salinity in the production and distribution of intertidal diatoms is discussed.     

Fouling organisms in the port of Mar del Plata (Argentina). I. Siphonaria lessoni: ecological and biometric aspects

The present paper deals with ecological aspects of the pulmonate gastropod Siphonaria lessoni (Blainville, 1824), a common member of fouling communities in Mar del Plata's port (38°0817 S, 57°3118 W). Populations on colonized panels of an experimental raft were studied during three annual cycles, to determine feeding habits, growth and various factors which restrict their distribution on floating substrata. Although S. lessoni is harmless as a fouling organism, its grazing on the algal belt clears a part of the substratum's surface, which is then quickly colonized by truly aggressive organisms such as Balanus amphitrite.     

Adaptation and equivalence in open-ocean phytoplankton

Two marine phytoplankton species of the North Atlantic Ocean have inherently differt growth responses to changing nutrient conditions. Yet they co-occur. Thus, they can be compared under the same conditions via equivalence, provided that their adaptedness is linked to their responsiveness as follows. If Species x is adapted to nutrient changes, then it is responsive to these conditions and, certainly, if it is responsive to these conditions, then it is adapted to them. There is another expression that is equivalent to this one (that says the same thing): either Species x is adapted and responsive to these conditions or it is neither adapted nor responsive to them. The option just mentioned is resolved so that Emiliania huxleyi as Species x is adapted and responsive and Cyclococcolithus leptoporus as Species x is not adapted and not responsive. All the frequently observed species in the winter half of the year, November to April, from 1961 to 1972 are like E. huxleyi in being adapted and responsive or like C. leptoporus in being unadapted and unresponsive.Contribution No. 5806 from the Woods Hole Oceanographic Institution     

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.