首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 531 毫秒
1.
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.  相似文献   

2.
“Copper” granules in the barnacle Balanus balanoides   总被引:1,自引:0,他引:1  
G. Walker 《Marine Biology》1977,39(4):343-349
Balanus balanoides (L.) collected from an area with high heavy-metal run-off contained two different types of granule within the parenchyma cells of the prosoma. X-ray microprobe analysis shows one to be the familiar zinc granule made up of concentric layers and giving major peaks for phosphorus and zinc, and the other to be homogeneous and giving peaks for sulphur and copper. This latter granule is designated the copper granule. Whilst zinc granules are known to be composed of inorganic phosphate, various tests on copper granules in sections and in a granule-rich pellet have shown that the copper is probably complexed with organic matter. The tests also demonstrated the relatively, insoluble (inert) nature of these granules. Although zinc and copper granules were present together in the prosoma, atomic absorption analyses of whole bodies (prosoma+thorax) have shown the level of zinc (50.28 g/mg dry weight) to be much higher than that of copper (3.75 g/mg dry weight).  相似文献   

3.
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.  相似文献   

4.
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.  相似文献   

5.
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.  相似文献   

6.
Summary In many altricial species including the great tit (Parus major) the intensity of brood defense against predators has been shown to increase with the age of the offspring. This effect has been ascribed amongst others to the young becoming more vulnerable as they age (vulnerability hypothesis). In a great tit population suffering heavy losses from brood depredation by the great spotted woodpecker (Dendrocopus major), we rendered first and second broods more vulnerable by artificially enlarging the entrance of the nest hole. Contrary to the vulnerability hypothesis, 16 experimental pairs defended their brood against a dummy great spotted woodpecker less vigorously than did 16 control pairs. Nest concealment behavior potentially compromising active defense was minimized by simultaneous playback of nestling distress calls, thus simulating the act of nest predation. This leaves the brood value hypothesis as an alternative functional explanation of the defense level — age effect. It predicts that parents should defend their brood in proportion to the reproductive value (or some more suitable cohortal equivalent measure) of their offspring. At present, this explanation pertains to one predator species. In first broods, but not in second broods, males defended them more vigorously than did their females. While this parallels previous experiments on brood defense against predators posing a much greater risk to the parents, two functional explanations previously put forward can hardly apply.  相似文献   

7.
Analyses of individual content of carbon (C), nitrogen (N), and hydrogen (H) were carried out for all larval stages of Pagurus bernhardus and Carcinus maenas, and for newly metamorphosed crabs. Maximum range in total larval development is 12.8 to 165.8 g C, 3.2 to 35.1 g N, and 1.9 to 24.9 g H in P. bernhardus and 3.1 to 43.2 g C, 0.7 to 10.1 g N, and 0.4 to 6.3 g H in C. maenas. From these data energy equivalents were calculated. Maximum range in total larval life is 0.43 to 6.38 J ind. -1 in P. bernhardus and 0.1 to 1.49 J ind. -1 in C. maenas. There is a 32.4% mean loss of energy in P. bernhardus megalopa development; this seems to describe the normal developmental pattern in this stage. Biomass was determined as fresh and dry weight respectively. Individual dry weight is about 3.6 to 5.6 times higher in P. bernhardus (44 to 340 g) than in C. maenas (12 to 93 g) larvae.Contribution to research project Experimentelle marine Ökosystemanalyse sponsored by Bundesministerium für Forschung und Technologie, Bonn (Grant No. MFU-0328/1)  相似文献   

8.
Samples of urban dusts and sediments have been collected and categorised into three compartment those which act mainly as sources, those undergoing transport and those which have been deposited. The sediments were fractionated into <63m to match similar sized lacustrine sediments and <2mm to represent natural and anthropogenic fluvially transported sediments. Preliminary results of total heavy metals analysis show that the <2mm fraction of the source group exhibits the greatest variabilty in metal concentrations. Overall, however, the <63m fraction dominates regardless of compartment. Some heavy metal concentrations decrease through the sourcetransportdeposit process, possibly due to selective onward transport of finer material or other anthropogenic processes unique to the urban environment (e.g. street cleansing). Sitespecificity is indicated in a comparison with other similar studies.  相似文献   

9.
More than 60 coal samples, predominantly from the principal coalfields of England and Wales (25) and Scotland (30), were analysed for lead by AAS and for stable lead isotopes by ICPMS. While the average lead content of Scottish coal, 23.9mg kg–1, was more than double that of coal from England and Wales, 11.0mg kg–1, the corresponding mean 206Pb/207Pb ratios (± 1 s.d.) were nearly identical, at 1.181±0.011 and 1.184±0.006, respectively. In the light of the lead isotopic signatures of British coals and of both indigenous (206Pb/207Pb 1.17) and imported Australian (206Pb/207Pb 1.04) lead ores, an approach based on estimated lead emissions from these sources and the deconvolution of the historical lead and 206Pb/207Pb records preserved in lake sediments, peat bogs and archival herbage material indicates that coal combustion became an increasingly significant contributor to atmospheric lead deposition in the UK during the period 1830–1930, especially after the onset of Englands decline as a major location of lead mining and smelting in the late19th Century. Since 1930 and the introduction of leaded petrol, the atmospheric 206Pb/207Pb ratio in the UK has been strongly influenced by carexhaust emissions of comparatively 206Pbdepleted lead of predominantly Australian origin, counterbalanced to some extent by coalcombustion emissions of lead, although these have fallen dramatically since the mid1950s. Nevertheless, with the introduction and substantial uptake of unleaded petrol in the UK during the last decade, even the declining releases from coal, along with contributions from other sources, are continuing to affect the atmospheric lead content and 206Pb/207Pb ratio.  相似文献   

10.
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.  相似文献   

11.
This paper presents a method of investigating the distributional pattern of a biological population, using a technique of simulation. The method consists of the comparison of the empirical frequency curve of a population, obtained using the Method of Quadrats, with a simulated one, since the pattern of the simulated curve depends on the simulated distribution. An example is given.  相似文献   

12.
Dystrophic crises or malaígues with red water, were observed in summer, in Mediterranean brackish lagoons near Montpellier, France. During July 1976, the photosynthetic sulfide-oxidizing bacteria causing this phenomenon were isolated from the Prévost lagoon. The most important genera isolated from this red water wereChromatium, Thiocystis andThiocapsa (Chromatiaceae): the predominant species wasThiocapsa roseopersicina. Water and sediment samples from the same lagoon were collected during the winter season (October 1976 and January 1977) and were enriched with organic matter. The samples were incubated in aquaria under artificial light (800 to 1000 lux) at room temperature (ca. 22°C). Eight to 10 days later, red water developed which was similar to that observedin situ in summer. These red waters develop under conditions of anaerobiosis and H2S production. Such conditions are necessary for the growth of Chromatiaceae. Excessive deposists of organic matter in the lagoon water lead to increased oxygen consumption and overproduction of hydrogen sulfide, which can be oxidized by photosynthetic sulfideoxidizing bacteria. This bacteria bloom (causing the red water) removes the hydrogen sulfide, thus re-establishing aerobiotic conditions in the water of the Prévost lagoon.  相似文献   

13.
Chitinase andN-acetyl--D-glucosaminidase activity were quantified inPalaemon serratus (Pennant) integument and midgut gland during the moulting cycle. Studies were performed on specimens collected near Concarneau, France, in July 1989. The changes in specific activity are different in the two organs: in the midgut gland enzymatic activity is high throughout the whole moulting cycle with a weak peak at the early premoult Stage D1, whereas in the integument the activity of both enzymes is very low throughout post- and intermoult stages and rises only after premoult Stage D1. The highest specific activity is reached in D1 for chitinase and somewhat earlier (D1) forN-acetyl--D-glucosaminidase. The increase in specific chitinolytic activity coincides with an increase in ecdysteroids.  相似文献   

14.
Environmental Accumulation of Airborne Fluorides in Romania   总被引:2,自引:0,他引:2  
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
K. Gocke 《Marine Biology》1977,40(1):87-94
The distribution of some microbial parameters was studied at 3 stations in the Central Baltic Sea (Bornholm Basin, BB; Danzig Deep, DD; and Gotland Deep, GD) during May 1976. The following analyses were performed: total bacterial numbers and biomass, viable counts and maximum uptake velocity (V max) of glucose. The values found for thesurface, samples were, total bacterial counts: 0.6x106 (BB); 1.7x106 (DD); 0.4x106 (GD) cells/ml; bacterial biomass: 1.9 g C/l (BB); 6.9 g C/l (DD); 1.6 g C/l (GD); viable counts: 0.37x103 (BB); 17x103 (DD); 0.4x103 (GD) counts/ml; V max: 0.01 g glucose-C/l (BB), 0.06 g glucose-C/l (DD); 0.01 g glucose-C/l (GD). The relatively high microbial numbers and activities of the Danzig Deep may be associated with the fertilization of the area by the River Vistula. The vertical distribution of the microbial parameters in the Bornholm Basin and Danzig Deep showed high values both in the top layer (0 to 20 m) and in the deep layer (>40 m). In the intermediate layer, however, the values decreased significantly. It is suggested that the high values of the microbial parameters at depth are caused by at least two major processes during the inflow of North Sea water into the deep layers of the Baltic Sea: (1) the North Sea water may already have contained high numbers of bacteria; (2) during the inflow, the high concentrations of bacteria normally located at the sediment-water interface are distributed throughout the whole deep layer by mixing.

Beitrag Nr. 143 aus dem Sonderforschungsbereich 95 Wechselwirkung Meer-Meeresboden, Universität Kiel.  相似文献   

18.
At 33 salinity a tissue stump formed 2 to 3 d after autotomy and developing ossicles were present by the fourth day inOphiothrix angulata (Say). Regeneration proceeded rapidly from the sixth day until the thirteenth day, when the rate decreased greatly. The length of the regenerated arm and the number of ossicles formed did not vary over a salinity range of 28 to 38 S, but were significantly less at 23 S. The number of ossicles regenerated increased linearly (y=1.9 x-7.7;r=0.9089) with the calcium concentrations ranging from 3.8 to 9.5 mM. No ossicle formation occurred at 3.8 mM calcium concentration. Rate of net uptake of calcium-45 into the ossicles of intact individuals in salinities of 28 and 33 was significantly greater than that in 23 and 38 S. However, net uptake rate of calcium into the soft tissues of the arms was significantly higher at 18S than at the lower two salinities.  相似文献   

19.
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.  相似文献   

20.
Common mussels, Mytilus edulis (shell length 19 to 21 mm, average dry weight 30 mg) were maintained for 6 weeks in sea water containing different concentrations of lead (0.005 to 5 mg · l-1). The lead concentration in the mussels' whole soft parts was analysed at different times during the experiment. A constant rate of lead uptake, linearly dependent on the lead concentration of the medium, was observed. Thus, the temporal change of the concentration factor is also linear (regression coefficient 149.9 daily). Rate of lead loss, measured after transferring the mussels into natural sea water, is linearly dependent on the original lead concentration in the soft parts. Rates of uptake and loss in large mussels (shell length 45 to 55 mm, average dry weight 750 mg) are less than those in small mussels (shell length 19 to 21 mm, average dry weight 30 mg). During a much more extended experimental period, adjustment to a steady state is expected to occur; rates of lead uptake and loss are then non-linear. Lead uptake by individual organs (kidney, gills, adductor muscle, digestive gland, foot, mantle with gonads) of large M. edulis (shell length 45 to 55 mm, average dry weight 750 mg) was analysed in 2 test series. In the test series medium, the mussels were kept in a seawater medium containing 0.01 mg. Pb.l-1. In the test series food, the mussels were kept in natural sea water but fed with the green algae Dunaliella marina containing lead (approximately 600 g.g-1 dry weight). The lead quantity given per mussel per day was about 2 g in both test series. Within 35 days, the mussels of test series medium took up 29% of the total amount of lead given, those of test series food took up 23.5%. In all organs, lead concentration increased, but rates of uptake differed; the kidney displayed by far the highest rate of uptake. With these physiological properties M. edulis is an ideal indicator organism for lead pollution in the marine environment. A biologic calibration curve, the relationship between lead concentration in the mussels' whole soft parts at equilibrium and lead concentration in sea water, is presented.This paper forms part of a doctoral thesis in biology at Hamburg University  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号