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1.
Transformation of some dissolved organic compounds by a natural heterotrophic population 总被引:2,自引:0,他引:2
Uptake of radioactively labeled glycolic acid, arginine, glutamic acid, and glycine by natural marine bacterial population was rapid and approached a maximum value which was over 90% of the total substrate. Uptake of glucose was rapid, but had a maximum uptake of less than 80%. All substrates except glycolic acid were assimilated to a similar degree (a maximum of more than 30% of the total given substrate). Glycolic acid had a maximum assimilation of less than 10%. The presence of glycolic acid resulted in no extracellular metabolites detectable on a gel permeation column. Between 5 and 10% of the other substrates were transformed and excreted within 72 h by the bacteria. These exudates were both nominally larger and smaller than the given substrates.NORDA publication number: JA 330:008:80 相似文献
2.
Discharges of nutrients, urea, dissolved organic matter and heavy metals by a sewage underwater pipeline are analysed in comparison to environmental conditions in a shallow coastal zone. Variable thermo-haline stratifications of the water column and currents in upper (2.62-34.97 cm s-1) and deeper (0.83-10.91 cm s-1) layers drive vertical diffusion and lateral transport of wastewaters. Loads of reactive phosphorus (0.13 tons d-1) and ammonium (1.62 tons d-1) by the pipeline are not negligible compared to the major river loads in the gulf. High concentrations of urea (≤11.51 μmol N dm-3) were found in the area of wastewater release. Ammonium uptake (6.14-534 nmol N dm-3 h-1) strongly exceeded nitrate uptake (0.19-138 nmol N dm-3 h-1), indicating that discharges of ammonium by the pipeline are actively assimilated by plankton community even at low levels of light. Distribution of Zn (≤27.7 ppb), Cu (≤25.6 ppb), Cd (≤0.80 ppb) and Pb (≤13.5 ppb) in the water column and the measurement of their complex-forming capacity in seawater did not indicate a persistent perturbation of the pelagic environment due to heavy metals. 相似文献
3.
Thymidine incorporation as a measure of heterotrophic bacterioplankton production in marine surface waters: Evaluation and field results 总被引:67,自引:0,他引:67
To assess bacterioplankton production in the sea, we have developed a procedure for measuring growth based on incorporation of tritiated thymidine into DNA; the accuracy of this procedure was tested under a variety of laboratory and field conditions. By autoradiography, we have found that for all practical purposes our technique is specific for the nonphotosynthetic bacteria and that virtually all of the active bacteria (one-third or more of the total countable bacteria) take up thymidine. We also measured (1) the intracellular isotope dilution of thymidine assessed by parallel experiments with labeled phosphorus, and (2) DNA content of natural marine bacteria (0.2 to 0.6 m size fraction); a conversion factor derived from these data permitted estimation of production from thymidine incorporation results. A very similar conversion factor was independently derived from the empirical relationship between thymidine incorporation and growth of natural bacterioplankton under controlled conditions. Combined results show that this technique, which can be performed rapidly and easily at sea, provides good estimates of production. Data from Southern California Bight waters, which contain oligotrophic as well as moderately eutrophic regions, show that average bacterioplankton doubling times, like those of the phytoplankton, are on the order of a few days, with fastest growth at depths just below those of greatest phytoplankton abundance. Offshore bacterial production is roughly 5 to 25% of the primary production; thus, at a 50% assimilation efficiency, the bacterioplankton would consume 10 to 50% of the total fixed carbon. 相似文献
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An autoradiographic examination of carbon fixation, transfer and utilization in the Riftia pachyptila symbiosis 总被引:4,自引:0,他引:4
Riftia pachyptila, the giant vestimentiferan tubeworm from the East Pacific Rise, harbors abundant chemolithoautotrophic, sulfide-oxidizing
bacteria in an internal organ, the trophosome. Several facts, such as the lack of a digestive system in the host, stable carbon
isotope values and net carbon dioxide uptake all suggest that the tubeworms obtain the bulk of their nutrition from their
symbionts. Using tissue autoradiography, we investigated the mode of nutritional transfer between symbionts and host, and
the site of early incorporation of symbiont fixed-carbon in the host. Fast labeling in the trophosome clearly demonstrates
that the symbionts are the primary site of carbon fixation. Appearance of label in some symbiont-free host tissues in as little
as 15 min indicates that the symbionts release a significant amount of organic carbon immediately after fixation. The organic
carbon is largely incorporated into specific, metabolically active host tissues such as fast-growing body regions in the trunk
and plume, and into tube-secreting glands. In addition to immediate release of fixed carbon by the symbionts, there is evidence
of a second possible nutritional mode, digestion of the symbionts, which is consistent with previous suggestions based on
trophosome ultrastructure. Results suggest that symbiont-containing host cells migrate in a predictable pattern within trophosome
lobules and that symbiont division occurs predominately in the center of a lobule, followed eventually by autolysis/digestion
at the periphery of the lobule.
Received: 1 July 1999 / Accepted: 30 December 1999 相似文献
7.
Diel photosynthetic production of water-extractable and residual carbohydrates in natural phytoplankton populations was investigated by analyzing monosaccharide components with combined gas chromatography/mass spectrometry (GC/MS) and13C tracer methods. The applicability of this technique for measuring the photosynthetic production of natural phytoplankton populations was examined. Phytoplankton was collected in August 1984 from Kinu-ura Bay, Japan, and incubated under natural light and dark conditions for 24 h. Cell density and concentration of chlorophylla increased about four- and three-fold, respectively, during the experimental period. Production of glucose, galactose, mannose, rhamnose, ribose, fucose, xylose and arabinose was measured in the water-extractable and residual carbohydrate fractions of the phytoplankton. Most of the monosaccharides in both fractions were produced the monosaccharides in both fractions were produced mainly during the daytime. Glucose was a major component in the water-extractable carbohydrate fraction produced by the phytoplankton, and decreased markedly at night. Thus, most of the glucose in the water-extractable carbohydrates seemed to be a constituent of the storage glucan of algal cells. Most monosaccharide components of the water-extractable carbohydrate fraction except glucose did not decrease significantly at night. Ribose of the water-extractable carbohydrate fraction was synthesized at a maximum rate in the morning, prior to the other monosaccharide constituents of this fraction. The major monosaccharide constituent in the residual carbohydrate fraction produced by the phytoplankton was glucose, which decreased significantly at night. Diel change in the production of monosaccharide constituents in residual carbohydrates indicated wide variability in the monosaccharide composition of cell-wall material in algae. The ratios of production of water-extractable and residual carbohydrates to POC production ranged from 8.8 to 28% and from 3.7 to 5.9%, respectively, throughout the daytime and nighttime. 相似文献
8.
Chunli Chen Tieyu Wang Jong Seong Khim Wei Luo Wentao Jiao 《Chemistry and Ecology》2013,29(2):165-176
Concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and other perfluorinated compounds (PFCs) were measured in water and sediment from coastal Bohai Bay and surrounding rivers flowing into the bay. Of the 15 PFCs measured, PFOS and PFOA were detected with the greatest frequency. Concentrations in water ranged from<0.2 to 31 ng·L?1 and<1.0 to 82 ng·L?1 for PFOS and PFOA, respectively. Concentrations of PFOS and PFOA in sediments ranged from<0.1 to 2.0 ng·g?1 dw and<0.1 to 0.5 ng·g?1 dw, respectively. Concentrations of PFCs in Bohai Bay were less than those observed in other areas in Asia, but greater concentrations of ∑PFCs were observed in the Dalin River with concentrations increasing from upstream to downstream, and the greatest concentrations in sediment were observed in tidal flats. The ratio of ∑PFCs in sediment and water indicated that sediment could serve as a significant sink for PFUnA. 相似文献
9.
Leonardo K. Miyashita Mayza Pompeu Salvador A. Gaeta Rubens M. Lopes 《Marine Biology》2010,157(11):2511-2519
We studied the population dynamics and the reproductive biology of Penilia avirostris during three consecutive years on the inner shelf off Ubatuba, Brazil. Penilia avirostris individuals and its eggs and embryos were counted, measured, and classified into stages. The species occurred throughout
the studied period, in a wide temperature range (14.8–28.2°C). Cladoceran densities were usually higher (>2,000 ind m−3) in warm seasons, when the water column was stratified as a consequence of bottom intrusions of the cold- and nutrient-rich
South Atlantic Central Water. Juveniles, non-reproducing females, and parthenogenic females were the dominant developmental
stages. Males and gamogenic females were rare and only occurred when females reached peak abundances. This suggests that in
tropical and subtropical coastal seas gamogenesis in P. avirostris is not as common as in temperate seas, but may play a significant role in the density-dependent control of the population
preceding unfavourable periods. 相似文献
10.
Stomach contents of the sea star species Astropecten aranciacus (L.) and A. bispinosus (Otto) consisted of roughly the same sort of prey, mostly bivalves and irregular sea urchins. However, the two predators ingested prey of different size classes. The stomach contents of A. bispinosus reflected the size distribution of the benthic macrofauna, while larger prey was more frequent in the stomach contents of A. aranciacus. As the density of prey in the investigated area is low, A. aranciacus and A. bispinosus are likely to compete for food. Possible mechanisms reducing the effect of competition are discussed. 相似文献
11.
The loss of organic matter and nutrients due to a natural fire in a Danish coastal dune heath system (175 ha) was studied
for three heath types: dryEmpetrum nigrum heath, moistE. nigrum-Vaccinium uliginosum heath, and wetErica tetralix-Molinia coerulea heath. The highest loss of organic matter, as well as N, P and K, was found in the moist heath (67%, 68%, 20% and 25% respectively).
The lowest loss was found in the wet heath (35%, 28%, 14%, and 11% respectively). The loss in the dry heath was intermediate.
For the burnt heath in total, loss of organic matter, N, P and K of about 13000, 192, 10 and 6 tons respectively, was estimated.
Processes of nutrient loss by fire and regeneration of nutrients are discussed. 相似文献
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Zhang Wei Tang Xiangyu Thiele-Bruhn Sören 《Environmental geochemistry and health》2021,43(10):4299-4313
Environmental Geochemistry and Health - Pharmaceutically active compounds (PhACs) released into the environment have an adverse impact on the soil and water ecosystem as well as human health.... 相似文献
14.
Complexity and uncertainty play important roles in coastal management. Economic development may push the coastal system beyond
its resilience thresholds as a result of interactions between environmental and socio-economic processes. The concepts in
this paper link processes of system change, natural evolutionary processes observed in coastal zones, to processes of social
evolution. An indicator based on calculating an ecological footprint for coastal zones is presented to guide decision-making
in spatial and economic planning. The suggested indicator may support a range of methods linking economic valuation and environmental
impact analysis. 相似文献
15.
Distribution dynamics of fish larvae and juveniles in the coastal waters of the Tanshui River, Taiwan was studied fortnightly using surface horizontal tows with a larval net in daytime during the period from early April through early June 1991. Environmental factors, including water temperature, salinity, dissolved oxygen, pH, transparency and depth at sampling stations, were also monitored. A total of 10737 fish eggs and 1387 individuals, representing 43 families and 93 species, was collected during five cruises from 12 stations in the coastal waters. Most fish were estuarine-dependent marine species. Liza macrolepis, Ambassis gymnocephalus, Terapon jarbua, Mullidae and Gobiidae were the most dominant, making up 64.7% of the total catch. Early life stages, including egg, preflexion, flexion and postflexion larvae were abundant in surface samples. However, yolk-sac larvae were absent in the surface water, probably due to an ontogenetic behavioral shift as a consequence of a change in specific weight during early development. The species composition of fish larvae and juveniles was related to the microhabitats found in the coastal waters. The physico-chemical conditions, along with ontogenetic behavior, played an important role in larval fish distribution in the coastal waters. 相似文献
16.
Leaching of dissolved organic carbon (DOC) from dead leaves,formation of flakes from DOC,and feeding on flakes by crustaceans in mangroves 总被引:4,自引:0,他引:4
Organic matter was released into sea water from dead mangrove leaves, under both biotic and abiotic conditions. Particulate matter (flakes) formed in the leachates under both conditions. Flakes cultured in the laboratory and flakes obtained from natural environments were colonized by microbial organisms and were utilized as food by copepods, amphipods, isopods, crabs and shrimps. This suggests an alternative pathway of energy transfer to that in the classical plant-grazer-carnivore communities. Since the leaching of organic matter from plant material and the formation of particulate matter from dissolved organic carbon are faster than the grazing of fallen leaves by metazoans, the alternative pathway may result in a faster rate of energy transfer from vascular plants to higher trophic levels than is found in grazer communities. 相似文献
17.
Decomposition of organic and solubilisation of inorganic phosphorus compounds by bacteria isolated from a marine sandy beach 总被引:4,自引:0,他引:4
The ability to decompose organic and to solubilise inorganic phosphorus compounds was studied in heterotrophic bacteria isolated from a sandy beach in Sopot, southern Baltic coast. Bacteria able to hydrolyse DNA and phytin were most numerous, while only a small percentage of the studied strains was able to depolymerise glycerophosphate. The ranking of the potential of the studied bacteria to solubilise metallic phosphate salts as follows: calcium hydrogen phosphate>ferric phosphate>magnesium phosphate>calcium phosphate>aluminium phosphate. There were marked differences in the level of depolymerisation of organic compounds of phosphorus and solubilisation of inorganic phosphorus between bacteria inhabiting different parts of the studied beach, while there were generally no differences between the surface and subsurface sand layers. The activity of alkaline phosphatase was higher than that of acid phosphatase.Communicated by O. Kinne, Oldendorf/Luhe 相似文献
18.
J. C. Gamble 《Marine Biology》1970,6(2):121-127
The pleopod ventilatory activity of the tube-dwelling amphipods Corophium volutator (Pallas) and C. arenarium
Crawford is intermittent. Unlike the free-living amphipod Marinogammarus obtusatus (Dahl), which increases its rate of pleopod beating, the pleopod beat rate of both Corophium species is unaffected by low oxygen concentrations. However, the nature of the intermittent ventilation rhythm is altered so that, at low oxygen concentrations, the pleopods of Corophium beat almost continuously. It is suggested that the intermittent ventilation of Corophium can be interpreted as an adaptation to a tubicolous existence. The peracaridean Tanais chevreuxi
Dollfus has 2 independent ventilatory systems, the maxilliped epipodites and the pleopods. The former, which respond to low oxygen concentrations, are thought to be the principal respiratory organs of T. chevreuxi, while the pleopods, which show no response to low oxygen tensions, are believed to be primarily concerned in filter feeding. 相似文献
19.
Yuanyuan Luo Yangyang Zhang Mengfan Lang Xuetao Guo Tianjiao Xia Tiecheng Wang Hanzhong Jia Lingyan Zhu 《Frontiers of Environmental Science & Engineering》2021,15(5):96
20.
S. M. Haq 《Marine Biology》1972,15(3):221-235
The breeding of Euterpina acutifrons, a marine harpacticid copepod, was studied both in the laboratory and in the natural population round Anglesey, England, with special reference to dimorphic males. As a result of successful rearing of the species under laboratory conditions, rates of development at different temperatures, and survival and maturation of all types of adults were studied. The dimorphic males developed faster than the females, and the small males had a shorter development time than the larger individuals. Laboratory observations clearly indicated that the males differ markedly in sexual behaviour, the small male being more potent, readily copulating with females, and always very active in breeding. In natural populations, temperature was found to have a limiting influence on the breeding period. Breeding began when the temperature reached 15° to 16°C, and ceased when it fell to 8°C. The most significant feature was the production of small males in nature; they increased in number with the onset of breeding, and always formed a high proportion of the actively breeding population. Both laboratory and field investigations have shown that the small male is a breeding form, and is apparently an adaptation of the species for carrying out successful breeding in the colder areas of its distribution. 相似文献