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1.
Edna Cabecinha Paul J. Van den Brink João Alexandre Cabral Rui Cortes Martinho Lourenço Miguel Ângelo Pardal 《Hydrobiologia》2009,628(1):27-45
Phytoplankton communities are structured by factors acting over temporal and spatial scales. Identifying which factors are
driving spatial patterns in aquatic communities is the central aim of ecology. In this study, data sets of phytoplankton communities
and environmental data of two Portuguese reservoirs types (lowland “riverine reservoirs” and higher altitude “artificial lake
reservoirs”) were used to determine the importance of environmental variables at different spatial (geographical, regional
and local) and time scales (seasons, years) on the community structure. In all the data sets, the multivariate ordination
technique Canonical Correspondence Analysis (CCA) showed that regional and local scales explained the majority (9–18% and
13–19%, respectively) of the taxa variance. However, for “riverine reservoirs”, time variables were more important, explaining 27% of the variability in phytoplankton
assemblages. Variance partitioning was used to assess the individual importance of the three spatial scales and time for the
community structure of the two reservoir types. The majority of among-site variability (5.9–21.4%) was accounted for by time
variables, with local, regional, and geographical scale variables accounting for 3.3–5.6%, 3.7–4.5% and 2.6–2.9%, respectively.
The effects of different spatial scales on phytoplankton communities were clearly interrelated; thus, implying that phytoplankton
assemblages are capable of detecting stress from catchment to site scales.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Handling editor: J. Padisak 相似文献
2.
Keith Johnson 《Journal of biological physics》2012,38(1):85-95
Water nanoclusters are shown from first-principles calculations to possess unique terahertz-frequency vibrational modes in
the 1–6 THz range, corresponding to O–O–O “bending,” “squashing,” and “twisting” “surface” distortions of the clusters. The
cluster molecular-orbital LUMOs are huge Rydberg-like “S,” “P,” “D,” and “F” orbitals that accept an extra electron via optical
excitation, ionization, or electron donation from interacting biomolecules. Dynamic Jahn–Teller coupling of these “hydrated-electron”
orbitals to the THz vibrations promotes such water clusters as vibronically active “structured water” essential to biomolecular
function such as protein folding. In biological microtubules, confined water-cluster THz vibrations may induce their “quantum
coherence” communicated by Jahn–Teller phonons via coupling of the THz electromagnetic field to the water clusters’ large
electric dipole moments. 相似文献
3.
Hirokazu Toju 《Ecological Research》2011,26(2):239-251
Organisms are surrounded by their predators, parasites, hosts, and mutualists, being involved in reciprocal adaptation processes
with such “biotic environment”. The concept of “coevolution”, therefore, provides a basis for the comprehensive understanding
of evolutionary and ecological dynamics in biological communities and ecosystems. Recent studies have shown that coevolutionary
processes are spatially heterogeneous and that traits mediating interspecific interactions can evolve rapidly in natural communities.
Here, I discuss factors promoting the geographic differentiation of coevolutionary interactions, the spatial scales of the
geographic structuring, and the pace of coevolutionary changes, reviewing findings in the arms race coevolution involving
a long-mouthed weevil and its host camellia plant. Evolutionary, ecological, and population genetic studies on the system
illuminated that viewpoints from the aspect of “coevolving biosphere” were important for predicting how ongoing anthropogenic
change in global environment alter the spatiotemporal dynamics of biological communities. 相似文献
4.
Soil microalgal communities on an antarctic active volcano (Deception Island,South Shetlands) 总被引:1,自引:0,他引:1
Contemporary eruptive episodes and present volcanic activity at Deception Island have created a mosaic of different environmental
conditions. In this study, the microalgal communities inhabiting 18 sites differing in geology, degree of disturbance and
physico-chemical features (texture, water, organic matter and nutrient contents) were characterized in terms of composition,
species richness and biomass. One hundred and forty taxa were recorded, with richest communities associated with stable sites
and some of the poorest ones in locations affected by recent eruptions. In accordance, a canonical correspondence analysis
ordinated species and sites along the first axis according to the percentage of coarse particles, and degree of disturbance
(eigenvalues 0.79 and 0.65, P = 0.04). Results of a cluster analysis grouped firstly those algal taxa with high fidelity to one set of environmental conditions,
while “ubiquitous” ones had the lowest similarity values. These taxa, mainly filamentous Cyanobacteria and diatoms, are the
only colonizers of harsher or recently formed environments. 相似文献
5.
James Woodward 《Biology & philosophy》2010,25(3):287-318
This paper attempts to elucidate three characteristics of causal relationships that are important in biological contexts.
Stability has to do with whether a causal relationship continues to hold under changes in background conditions. Proportionality
has to do with whether changes in the state of the cause “line up” in the right way with changes in the state of the effect
and with whether the cause and effect are characterized in a way that contains irrelevant detail. Specificity is connected
both to David Lewis’ notion of “influence” and also with the extent to which a causal relation approximates to the ideal of
one cause–one effect. Interrelations among these notions and their possible biological significance are also discussed. 相似文献
6.
E. V. Balushkina 《Inland Water Biology》2009,2(4):355-363
In the years 1994–2005, the values of the integrated index IP’ at some stations of the Neva Bay changed from 38.1 to 81.9%, water quality changed from class 3 to class 5, and the states
of some areas of the ecosystem that were evaluated as “tense” went to “catastrophic.” The integrated mean assessment of water
quality according to the IP’ index over the entire Neva Bay throughout 12 years (1994–2005) remained relatively stable, waters were assessed as “polluted”
(fourth class), and the state of the ecosystem was considered “critical.” The state of the eastern part of the Gulf of Finland
in 1994–2005 was less favorable. The species diversity of zoobenthos in the resort zone of the eastern part of the Gulf of
Finland is considerably lower than in the Neva Bay. Waters of the resort zone of the eastern part of the Gulf of Finland in
1994–2005 were assessed as one class lower than in the Neva Bay, i.e., as “polluted-dirty” (fourth-fifth class), and the state
of the ecosystem was assessed as being in a “crisis.” In the resort zone, there was a decline in species diversity and abundance
and biomass of benthic animals; i.e., all characteristics of the degradation of benthic animal communities were observed. 相似文献
7.
River continuity is one of the hydro-morphological elements supporting the classification of the ecological status of rivers.
In order to achieve good ecological status in the continuity of rivers, the impacts of anthropogenic activities must be limited
to the extent that some fish age classes may be missing and there may only be slight changes in species composition and abundance
from the type specific community. The main goal of the project is to list priorities for removing obstruction to migration
within 12 years to reestablish river continuity so as to allow undisturbed migration of aquatic organisms. The ecological
status of the river, the cost–benefit ratio of the proposed restoration and the distance between obstructions are analysed.
More than 200 obstructions in about 170 km of river were evaluated. A 1st ranking of the parameter “extension of undisturbed
river length” shows significant alterations in comparison with the 2nd and 3rd ranking, where the river length is weighted
over the parameters “ecological status” of the river reach and the “cost–benefit ratio” of the measure. The ecological status
is classified by comparing the present versus the potential natural morphological conditions (Leitbild). The cost–benefit
ratio takes into account the increase of the fish species composition and the cost of the measures in relation to local circumstances
of available property and height of the drop. Examples of obstructions in the Pinka R. move back in the priority list to a
maximum of −9 places and forwards to a maximum of +8 places. As a result the list of obstructions by priority for removal
to be removed first at the top is analysed. The financial policy and a schedule for removal for the period 2003–2015 are based
upon the results of the priority list.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Guest editors: R. L. Welcomme & G. Marmulla
Hydropower, Flood Control and Water Abstraction: Implications for Fish and Fisheries 相似文献
8.
Anya Plutynski 《Biology & philosophy》2008,23(3):363-381
There have been two different schools of thought on the evolution of dominance. On the one hand, followers of Wright [Wright
S. 1929. Am. Nat. 63: 274–279, Evolution: Selected Papers by Sewall Wright, University of Chicago Press, Chicago; 1934. Am.
Nat. 68: 25–53, Evolution: Selected Papers by Sewall Wright, University of Chicago Press, Chicago; Haldane J.B.S. 1930. Am.
Nat. 64: 87–90; 1939. J. Genet. 37: 365–374; Kacser H. and Burns J.A. 1981. Genetics 97: 639–666] have defended the view that
dominance is a product of non-linearities in gene expression. On the other hand, followers of Fisher [Fisher R.A. 1928a. Am.
Nat. 62: 15–126; 1928b. Am. Nat. 62: 571–574; Bürger R. 1983a. Math. Biosci. 67: 125–143; 1983b. J. Math. Biol. 16: 269–280;
Wagner G. and Burger R. 1985. J. Theor. Biol. 113: 475–500; Mayo O. and Reinhard B. 1997. Biol. Rev. 72: 97–110] have argued
that dominance evolved via selection on modifier genes. Some have called these “physiological” versus “selectionist,” or more
recently [Falk R. 2001. Biol. Philos. 16: 285–323], “functional,” versus “structural” explanations of dominance. This paper
argues, however, that one need not treat these explanations as exclusive. While one can disagree about the most likely evolutionary
explanation of dominance, as Wright and Fisher did, offering a “physiological” or developmental explanation of dominance does
not render dominance “epiphenomenal,” nor show that evolutionary considerations are irrelevant to the maintenance of dominance,
as some [Kacser H. and Burns J.A. 1981. Genetics 97: 639–666] have argued. Recent work [Gilchrist M.A. and Nijhout H.F. 2001.
Genetics 159: 423–432] illustrates how biological explanation is a multi-level task, requiring both a “top-down” approach
to understanding how a pattern of inheritance or trait might be maintained in populations, as well as “bottom-up” modeling
of the dynamics of gene expression. 相似文献
9.
Jassey VE Chiapusio G Mitchell EA Binet P Toussaint ML Gilbert D 《Microbial ecology》2011,61(2):374-385
The ecology of peatland testate amoebae is well studied along broad gradient from very wet (pool) to dry (hummock) micro-sites
where testate amoebae are often found to respond primarily to the depth to water table (DWT). Much less is known on their
responses to finer-scale gradients, and nothing is known of their possible response to phenolic compounds, which play a key
role in carbon storage in peatlands. We studied the vertical (0–3, 3–6, and 6–9 cm sampling depths) micro-distribution patterns
of testate amoebae in the same microhabitat (Sphagnum fallax lawn) along a narrow ecological gradient between a poor fen with an almost flat and homogeneous Sphagnum carpet (fen) and a “young bog” (bog) with more marked micro-topography and mosaic of poor fen and bog vegetation. We analyzed
the relationships between the testate amoeba data and three sets of variables (1) “chemical” (pH, Eh potential, and conductivity),
(2) “physical” (water temperature, altitude, i.e., Sphagnum mat micro-topography, and DWT), and (3) phenolic compounds in/from Sphagnum (water-soluble and primarily bound phenolics) as well as the habitat (fen/bog) and the sampling depth. Testate amoeba Shannon
H′ diversity, equitability J of communities, and total density peaked in lower parts of Sphagnum, but the patterns differed between the fen and bog micro-sites. Redundancy analyses revealed that testate amoeba communities
differed significantly in relation to Eh, conductivity, water temperature, altitude, water-soluble phenolics, habitat, and
sampling depth, but not to DWT, pH, or primarily bound phenolics. The sensitivity of testate amoebae to weak environmental
gradients makes them particularly good integrators of micro-environmental variations and has implications for their use in
paleoecology and environmental monitoring. The correlation between testate amoeba communities and the concentration of water-soluble
phenolic suggests direct (e.g., physiological) and/or indirect (e.g., through impact on prey organisms) effects on testate
amoebae, which requires further research. 相似文献
10.
N. Rashevsky 《Bulletin of mathematical biology》1967,29(3):643-648
In continuation of previous studies (Bull. Math. Biophysics,28, 283–308; 655–661, 1966;29, 139–152, 1967) it is shown that the difference between the “metric” aspects of physics and the “relational” aspects of biological
and social sciences disappear by accepting the broader definition of “relation”, such as that given in mathematics and logic.
A conceptual superstructure then becomes possible from which all three branches of knowledge may be derived, though none of
them can be derived from the others. 相似文献
11.
Robert Rosen 《Bulletin of mathematical biology》1963,25(1):41-50
The environmentally induced alterations in structure of (M, ℜ) which were described previously (R. Rosen,Bull. Math. Biophysics,23, 165–171, 1961) are examined from the standpoint of determining under what circumstances they can be reversed by further
environmental interactions. For simplicity we consider only the case of (M, ℜ)-systems possessing one “metabolic” and one “genetic” component. In the case of environmentally induced alteration of
the “metabolic” component alone, a necessary and sufficient condition is given for the reversibility of the alteration. In
the case of alteration of the “genetic” component, the situation becomes more complex; several partial results are given,
but a full analysis is not available at this time. Some possible biological implications of this analysis are discussed.
This research was supported by the United States Air Force through the Air Force Office of Scientific Research of the Air
Research and Development Command, under Contract no. AF-49(638)-917 and Grant no. AF-AFOSR-9-63. 相似文献
12.
Curtis J. Richardson 《Wetlands Ecology and Management》2010,18(5):517-542
The Everglades is the largest subtropical wetland in the United States. Because of its size, floral and faunal diversity,
geological history and hydrological functions on the Florida landscape, the remaining Everglades are considered to be the
crown jewel of U.S. wetlands. It is also called a “sentinel wetland” to test our society’s resolve for ecosystem restoration.
Originally called Pa-hay-okee (“grassy lake”) by the American Indians, it was later popularized as the “river of grass” by
Marjory Stoneman Douglas. This metaphor unfortunately has led to a simplistic view of the complexities of the Everglades ecosystem
and how it functions on the landscape. Often incorrectly referred to as the “marsh” or “swamp,” the Everglades is a fen peatland
or alkaline mire. These are important distinctions when one considers how different marshes and swamps are from peatlands
in terms of their hydrologic controls, biogeochemistry, rate of peat development, plant and animal communities and-importantly-succession
patterns. This paper provides a brief review of the geological processes that led to the development of the Everglades, compares
historic and current hydrologic flow patterns, assesses nutrient conditions, presents information on vegetation communities
and succession patterns, and provides a new peatland classification of the Everglades system, which may help in the development
of a more appropriate restoration management framework. 相似文献
13.
Jing Zhang Yan Liu Dan Yu Hongze Song Jingjin Cui Tao Liu 《Journal of applied phycology》2011,23(2):165-171
Hybridization of gametophytes, continuous self-crossing and targeted selection were utilized to breed a new Laminaria variety. After five-generation selection breeding, the new variety “Rongfu” was obtained. Its male parent “Yuanza No.10”
was the high-yield cultivation variety, and its female parent was variety “Fujian” which could tolerate relatively high seawater
temperature. “Yuanza No.10” and “Fujian” were different but complement in their morphological characteristics and biological
habits. Variety “Rongfu” was bred through their hybridization which exhibited high-yield potential and high seawater temperature
tolerance. The results of traits evaluation in consecutive years showed that “Rongfu” attained higher yields by 24–27% compared
to the control (widely used commercial variety) and also contained considerable amounts of iodine, mannitol, and algin. When
seawater temperature was 18–21°C, the blade growth of “Rongfu” was maintained and tissue loss by abrasion was significantly
lower than the control. Since the adoption of variety “Rongfu” in 2001, its cultivation areas have been extended to Shandong,
Fujian and Guangdong province and have reached 14,133 ha currently, i.e., almost one-tenth of the total cultivation areas
of Laminaria in China. The results of Random Amplified Polymorphic DNA analysis showed that the relationship between “Rongfu” and other
cultivation varieties in China was very close. 相似文献
14.
Masayoshi Maehata 《Ichthyological Research》2001,48(3):283-287
The mating behavior of the rock catfish Silurus lithophilus (Siluriformes: Siluridae), a species endemic to the Lake Biwa system, was observed from May to July in 1989–1994 along the
rocky shore of the lake's outlet, the Seta River. The mating behavior of S. lithophilus involved a certain behavioral sequence: “chasing,”“clinging,” and “enfolding” while “squeezing” by the male; and “circling”
by the spawned pair. The mating behavior of this species was basically similar to that of S. biwaensis, but greatly different from that of S. asotus, which spawns in running water (in ditches). The mating behavior of S. lithophilus (and S. biwaensis) might have developed as an adaptation to lentic environments such as the shores of the large river or the lake.
Received: October 25, 2000 / Revised: February 25, 2001 / Accepted: March 8, 2001 相似文献
15.
Numerical fish-habitat modelling on various scales is considered to be state of the art in river management. However, most
of the concepts applied use steady-state hydraulic parameters such as flow velocity and water depth. Herein we present analysis
and discussion of the possibility of including a drift-feeding parameter (SIF) into habitat evaluations based on multiplying suitability indices. “Sources” and “sinks” of benthic drift were identified
according to both the zero-crossing and hydraulic-threshold methods in an alpine gravel-bed river. Minor differences could
be determined between the two methods in a well-developed riffle–pool section. Macroinvertebrates, used for simulating benthic
drift, were collected by multi-habitat sampling and appraised according to their critical threshold (τ
cr) for motion on the bed surface and sinking velocity (v
s). The findings of the calculation of drift rates using one- (1D) and two-dimensional (2D) hydrodynamic numerical models highlight
a specification of best feeding position for drift-feeding fish (i.e. brown trout, grayling) considering the SIF parameter. Riffle–pool sequences are characteristic of pristine alpine streams; our findings underline their importance as
production (riffles) and consumption areas (pools) in terms of holistic river function. Moreover, the results indicate that
(artificial) lateral obstruction (e.g. dams) may lead to a reduced transport rate of benthic organisms due to low bottom shear
stress (<0.25 N m−2). Thus, deposition of drifting macroinvertebrates occurs in backwaters, with downstream impacts on benthic and fish communities. 相似文献
16.
17.
Some bioengineering problems connected with the use of conventional and unconventional raw materials in fermentation research
and industry are reviewed. They include the effect of the physical state of different substrates (solid, liquid, gaseous)
and considerations of physico-chemical processes, especially the identification of limiting steps. A new concept of classification
of fermentors with respect to the macromixing properties is suggested and its applicability for different substrates is considered.
Presented at the seminar “Raw materials in the fermentation industry”, organized by the Czechoslovak Society for Microbiology,
Nové Město na Moravě, April 28–30, 1976. 相似文献
18.
S. Even B. Thouvenin N. Bacq G. Billen J. Garnier L. Guezennec S. Blanc A. Ficht P. Le Hir 《Hydrobiologia》2007,588(1):13-29
Within the framework of the European Water Framework Directive, the Seine-Normandie Water Agency has defined prospective scenarios
describing possible trends of evolution of the pressures on water resources. In order to evaluate the resulting water quality
improvement or degradation of water bodies in the Seine river basin, an integrated modelling was proposed. The approach consisted
in coupling three models, the seneque model for upstream sub-basins, the ProSe model for the Seine river and main tributaries and finally the s
i
am1d model for the downstream estuary. After consistency verification, the integrated model was applied to scenarios proposed
by the Seine-Normandie Water Agency. As a result of improvement in the nitrogen treatment by waste water treatment plants,
the annual load of ammonia at the basin scale will be reduced by 65%. The oxygen and ammonia criteria in the estuary will
improve from “bad” to “good”. However the nitrate criteria will remain “poor”, given the strong influence of non-point sources.
Despite a 70–75% drop of the point orthophosphate loads, the criteria for this variable will also remain “poor”. The nutrient
levels will be high enough to maintain eutrophication in the system; a general trend to a shift from N-limitation to P-limitation
will be accentuated. 相似文献
19.
V. V. Shakhparonov 《Biology Bulletin》2011,38(5):528-532
The behavior of frogs from southern areas with an arid climate released during the reproductive period between their “home”
pond and a less distant river is shown to be independent of weather conditions. The experiments were performed on frogs living
near the village of Dosang, Astrakhan oblast. The frogs were released 60 to 150 m from their “home” breeding waterbody and
60 to 80 m from an “alien” waterbody. Four experiments were performed on 27 individuals. The movements of the frogs were traced
by the method of “tracking by a thread.” The results revealed no preference in the frogs to return to their own breeding ponds,
rather than to the nearby river. This behavior is peculiar to frogs of southern populations. 相似文献
20.
Neeraja Sankaran 《Journal of the history of biology》2010,43(3):571-599
In 1936, Frank Macfarlane Burnet published a paper entitled “Induced lysogenicity and the mutation of bacteriophage within
lysogenic bacteria,” in which he demonstrated that the introduction of a specific bacteriophage into a bacterial strain consistently
and repeatedly imparted a specific property – namely the resistance to a different phage – to the bacterial strain that was
originally susceptible to lysis by that second phage. Burnet’s explanation for this change was that the first phage was causing
a mutation in the bacterium which rendered it and its successive generations of offspring resistant to lysogenicity. At the
time, this idea was a novel one that needed compelling evidence to be accepted. While it is difficult for us today to conceive
of mutations and genes outside the context of DNA as the physico-chemical basis of genes, in the mid 1930s, when this paper
was published, DNA’s role as the carrier of hereditary information had not yet been discovered and genes and mutations were
yet to acquire physical and chemical forms. Also, during that time genes were considered to exist only in organisms capable
of sexual modes of replication and the status of bacteria and viruses as organisms capable of containing genes and manifesting
mutations was still in question. Burnet’s paper counts among those pieces of work that helped dispel the notion that genes,
inheritance and mutations were tied to an organism’s sexual status. In this paper, I analyze the implications of Burnet’s
paper for the understanding of various concepts – such as “mutation,” and “gene,” – at the time it was published, and how
those understandings shaped the development of the meanings of these terms and our modern conceptions thereof. 相似文献