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1.
There are only few studies on shallow Antarctic benthic communities associated with habitats affected by intense mineral sedimentation
inflow. The analysis of macrofaunal communities associated with two shallow, isolated glacial coves was performed in Admiralty
Bay (King George Island) and compared with non-disturbed sites. Multivariate analyses (hierarchical classification, nMDS)
clearly separated glacial cove communities (two assemblages) from the sites situated outside both basins (two assemblages).
The community influenced by the streamflow of glacial discharge of meltwater situated in the area with sandy–clay–silt sediments
had a very low species richness, diversity and abundance. It was dominated by eurytopic, motile deposit feeding polychaetes
such as Mesospio
moorei, Tharyx
cincinnatus and Leitoscoloplos
kerguelensis as well as the bivalve Yoldia
eightsi. The second glacial community of the area located at a grater distance from the outlet of the stream was characterized by
sandy–clay–silt and clay–silt deposits and showed also a low diversity and species richness. The most abundant here were peracarid
crustaceans, with the dominant opportunistic feeder Cheirimedon
femoratus. Community from the non-disturbed area with silty–clay–sand, and silty–sand sediments had higher species richness and diversity.
The assemblage of fauna from the sandy bottom has values of those two indexes similar to those found in the disturbed areas. 相似文献
2.
Robert M. Newton Douglas A. Burns Veronica L. Blette Charles T. Driscoll 《Biogeochemistry》1996,32(3):299-322
During the fall of 1989 7.7Mg/ha of calcium carbonate was applied on two tributary catchments (40 ha and 60 ha) to Woods Lake, a small (25 ha) acidic headwater lake in the western Adirondack region of New York. Stream-water chemistry in both catchment tributaries responded immediately. Acid-neutralizing capacity (ANC) increased by more than 200 eq/L in one of the streams and more than 1000 eq/L in the other, from pre-liming values which ranged from –25 to +40 eq/L. The increase in ANC was primarily due to increases in dissolved Ca2+ concentrations. Most of the initial response of the streams was due to the dissolution of calcite that fell directly into the stream channels and adjacent wetlands. A small beaver impoundment and associated wetlands were probably responsible for the greater response observed in one of the streams.After the liming of subcatchmentIV (60 ha), Ca2+ concentrations increased with increasing stream discharge in the stream during fall rain events, suggesting a contribution from calcite dissolved within the soil and transported to the stream by surface runoff or shallow interflow. Concentrations of other ions not associated with the calcite (e.g. Na+) decreased during fall rain events, presumably due to mixing of solute-rich base flow with more dilute shallow interflow. The strong relation between changes in Ca2+ and changes in NO
3
–
concentrations during spring snowmelt, (r2 = 0.93, slope = 0.96, on an equivalent basis) suggests that both solutes had a common source in the organic horizon of the soil. Increases in NO
3
–
concentrations during snowmelt were balanced by increases in Ca2+ that was released either directly from the calcite or from exchange sites, mitigating episodic acidification of the stream. However, high ambient NO
3
–
concentrations and relatively low ambient Ca2+ concentrations in the stream during the spring caused the stream to become acidic despite the CaCO3 treatment.In stream WO2 (40ha), Ca2+ concentrations were much higher than in stream WO4 because of the dissolution of calcite which fell directly into the upstream beaver pond and its associated wetlands. Calcium concentrations decreased as both NO
3
–
concentrations and stream discharge increased, due to the dilution of Ca-enriched beaver pond water by shallow interflow. Despite this dilution, Ca2+ concentrations were high enough to more than balance strong acid anion (SO
4
–
, NO
3
–
, Cl–) concentrations, resulting in a positive ANC in this stream throughout the year. These data indicate that liming of wetlands and beaver ponds is more effective than whole catchment liming in neutralizing acidic surface waters. 相似文献
3.
Shima T Fukushima K Setoyama H Imaoka A Matsumoto S Hara T Suda K Umesaki Y 《FEMS immunology and medical microbiology》2008,52(1):69-77
Probiotics are used for the improvement of gut disorders. To explore the potential of probiotics, a gnotobiotic study using BALB/c mice to analyze epithelial gene expression was performed. Microarray analysis of probiotic strain-monoassociated mice showed that Lactobacillus casei Shirota and Bifidobacterium breve Yakult noticeably affected gene expression in the ileal and colonic epithelial cells, respectively, although to a smaller extent than segmented filamentous bacteria (SFB). Lactobacillus casei Shirota enhanced the gene expression involving defense/immune functions and lipid metabolism more strongly than B. breve Yakult. In the colon, expression of a chloride transporter was slightly enhanced, although downregulation of many genes, such as guanine nucleotide-binding protein, was evident in mice with B. breve Yakult compared with the ones with L. casei Shirota. SFB affected gene expression more strongly than the probiotic strains. In particular, alpha(1-2) fucosyltransferase and pancreatitis-associated protein were significantly enhanced only in SFB-monoassociated mice but not probiotic strain-monoassociated mice. Gene expression of SFB-monoassociated mice was either stimulated or repressed in a manner similar to or opposite that of conventional colonized mice. Taken together, probiotic strains of L. casei Shirota and B. breve Yakult differentially affect epithelial gene expression in the small intestine and colon, respectively. 相似文献
4.
Metal (Cu, Ni, Zn, Fe, Mn and Al) budgets were measured for 5 lakes and their catchments near Sudbury, Ontario, an area severely affected by the emission and deposition of strong acids (H2SO4/SO2) and metals. Three of the lakes were circum-neutral (pH 6.3–7.1) during the study period, while one lake had a pH of 4.8 and a fifth had very low pH ( 4.4).The lakes' catchments were all sources of Al, Mn and Ni, but were sinks for Cu and Zn. The Fe results were inconsistent; two lakes' catchments were sources while three were sinks.The acidic lakes were conservative (i.e. net retention of zero) with respect to Cu and Ni, while the circum-neutral lakes were effective sinks for these 2 metals. All of the lakes were sinks for Zn and Al, but the acidic lakes were less effective. All lakes were also Fe sinks. While there was no pattern relative to the lakes' pH's, there was a trend towards increasing Fe retention with increasing water replenishment time. The most acidic lake was actually a source of Mn, while the others were sinks. 相似文献
5.
Tomasz Lenard Wojciech Ejankowski Władysława Wojciechowska Michał Solis 《Biologia》2014,69(6):735-741
The aim of the study was to evaluate the effects of coniferous forest cover in the catchment basin and relative catchment area (catchment area to lake volume ratio) on phytoplankton composition in humic lakes. The study was carried out in 11 small and shallow lakes situated in the West Polesie region (Eastern Poland). The lakes were divided with respect to forest cover in their catchment basins into two groups: high forest cover — HFC (more than 60%) and low forest cover — LFC (less than 60%). The study showed that both, land use in the catchments (proportion of forests) and the relative catchment area determined physicochemical and biological parameters in the lakes. The high relative catchment area affects their high productivity expressed by high chlorophyll a concentration and low water visibility. The lakes of the LFC group had low water colour as well as high concentration of total phosphorus (Ptot), reaction (pH), and conductivity of water and a large number of cyanophytes and chlorophytes. The dominant species, e.g., Planktolyngbya limnetica, Limnothrix planctonica, Planktothrix agardhii, Coenococcus planctonicus, were characteristic of high trophic status. In the lakes of the HFC group, Ptot, pH, conductivity of water and the contribution of cyanophytes and chlorophytes was considerably lower, whereas the water colour and the number of raphidophytes represented by Gonyostomum semen was high. The large number of raphidophytes and the small amount of chlorophytes and cyanophytes in the lakes of the HFC group indicated the lake naturalness. 相似文献
6.
Being located in remote areas, alpine lakes are good indicators of regional and global pollution, and are particularly sensitive
to atmospheric depositions. When situated in areas where acidic rocks dominate, they are sensitive to acidification.
In the framework of an international project partially funded by the EU, a two-year study on zooplankton was carried out on
two lakes, Lake Paione Inferiore (LPI) and Lake Paione Superiore (LPS), selected because of their susceptibility to acidification.
In particular, LPS is permanently acidified, with pH ranging between 5.3 and 6.2, and LPI is acidified during the ice melt,
when pH drops to 6.1 units. In addition, LPI is subjected to further anthropogenic interference, since fish (Onchorynchus
mykiss) have been repeatedly introduced into the lake during the last thirty years.
Literature information is available on the species composition and the seasonal dynamics of the zooplankton communities of
the two lakes before these anthropogenic disturbances took place. Previously, the two lakes had a similar species composition
and abundant zooplankton. An analysis of the present-day situation reveals significant changes compared to the past. Both
acidification and the introduction of fish are responsible for the marked alterations observed. By reconstructing of the past
cladocera assemblages and by analysing the literature on lakes with different impacts of the two factors (pH and fish), we
can estimate the relative importance of the two different anthropogenic disturbances on species composition and abundance
of the zooplankton communities of the two lakes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
Esther M. Chan Alison M. Derry Lindsay A. Watson Shelley E. Arnott 《Hydrobiologia》2008,614(1):275-284
The maintenance of species and genetic diversity within zooplankton egg banks may be crucial to the re-establishment of zooplankton
communities following historical disturbance, such as anthropogenic acidification which globally caused widespread damage
to ecological communities. Despite this, no other study has described basic characteristics of zooplankton egg banks among
lakes with different acidification histories, such as variation in resting egg concentration. Theoretically, habitats with
frequent periods of harsh environmental conditions are expected to select for resting egg production or prolonged dormancy
in zooplankton, which would increase the size of the resting egg bank in lake sediments. In this study, we compared abundances
of viable and inviable calanoid copepod resting eggs among three freshwater lakes with different acidification histories.
While Swan Lake underwent major chemical and biological changes from acid and metal deposition, Teardrop and Bat lakes were
relatively unaffected by historical acidification and had comparatively constant, but different pH over time. We also tested
the effect of age on the viability of resting eggs. As predicted, higher numbers of viable resting eggs were found in recent
sediments from acid-recovering Swan Lake compared to study lakes with relatively temporally constant environments (Teardrop
and Bat lakes) when the total number of eggs was held as a covariate. We detected this result in spite of similar pelagic
abundances of Leptodiaptomus minutus, the dominant species in zooplankton communities of these lakes. This pattern did not necessarily hold for inviable egg concentrations
since these eggs were more abundant in both Swan and Bat lakes compared to Teardrop Lake in older sediments (1939–1951, 1800s).
Within study lakes, the abundance of viable resting eggs declined with increased egg age. Further study is required to test
mechanisms underlying these patterns.
Handling editor: S. I. Dodson 相似文献
8.
A. L. Antonov 《Journal of Ichthyology》2012,52(2):149-159
Taxonomic characteristics of the diversity of fishes in the mountain areas of the Russian part of the Amur Basin are provided and based on the author’s investigations; data are given on the distribution of fishes and on the structure and dynamics of ichthyocenoses in different parts of the studied mountain catchment areas. 相似文献
9.
10.
11.
12.
Bruno Bjärnborg 《Hydrobiologia》1983,101(1-2):19-26
The seasonal variation in water chemistry was followed during 1980 and 1981 in four mountain brooks in the southern part of Swedish Lapland. In the area investigated the soil is calcareous and the brook water is very well buffered during the major part of the year, with alkalinity varying between 0.4 and 1.0 milliequivalents per liter and with pH values about 7.5. These years the snow had a pH of approximately 5.2, which was considerably higher than has been reported from adjacent areas in the lower, coniferous region. During snowmelt the water discharge increased drastically, and although the net transport of bicarbonate increased, alkalinity showed low values due to dilution with meltwater. pH decreased, but not further than to 6.3–6.5, far from values reported in 1979 (pH less than 5), apparently due to the comparatively clean snow. A slight deficit in alkalinity, as compared to the nonmarine calcium and magnesium content, points to an acidification impact on the area. During maximum runoff some chemical variables, like aluminium, iron, nitrogen and phosphorus, behaved reversely to what might be expected during dilution and reached maxima in concentrations. It is concluded that the extreme runoff characteristics of high mountain areas make brook water more sensitive to acid precipitation than might be expected when regarding only the calcareous properties of soil and bedrock. 相似文献
13.
Life history characteristics of brown trout in lakes at different stages of acidification 总被引:1,自引:0,他引:1
In 66 Norwegian lakes with allopatric populations of brown trout Salmo trutta that ranged from highly acidified to non-acid (pH 4·7–6·6) there was a significant inverse correlation between mean age and relative abundance (CPUE). As mean annual survival rates were not significantly related to CPUE, this population response may indicate that recruitment was lower in low-density lakes. Age-specific masses were significantly higher in populations that had declined in abundance than in unaffected populations. Mean body mass at sexual maturity in both males and females was inversely correlated with CPUE. Between populations, high age at maturity was associated with high survival rates in both sexes. Age at maturity correlated positively with specific growth rate between the ages of 1 and 2 years in females only. 相似文献
14.
15.
GREGORY W. COURTNEY 《Systematic Entomology》1991,16(2):137-172
Abstract. A cladistic analysis of the Blephariceromorpha (here including the Nymphomyiidae, Deuterophlebiidae and Blephariceridae) and related Diptera provides a test of the phylogenetic hypotheses of Rohdendorf (1964, 1974), Hennig (1973), Wood & Borkent (1989) and Courtney (1990a). In particular, monophyly of the Blephariceroidea and Blephariceromorpha (sensu Wood & Borkent), and their relationship to other Diptera, is tested. Evaluation of larval, pupal and adult characters supports the hypothesis of Wood & Borkent, as modified by Courtney. Four larval features suggest that the Blephariceromorpha + Psychodomorpha form a monophyletic group, although an alternate hypothesis predicting that the Blephariceromorpha is the sister group of the Psychodomorpha + (Ptychopteromorpha + Culicomorpha), is discussed. Monophyly of the Blephariceromorpha (Nymphomyioidea + Blephariceroidea) is supported by one adult and five larval characters. Monophyly of the Blephariceroidea (Deuterophlebiidae + Blephariceridae) is supported by thirteen synapotypies, including features of the larva (six), pupa (three) and adult (four). Nineteen, nineteen and nine hypothesized synapotypies support monophyly of the Nymphomyiidae, Deuterophlebiidae and Blephariceridae, respectively. 相似文献
16.
17.
M Stopiński 《Acta microbiologica Polonica》1981,30(3):283-294
The number of bacteria capable of growth at low temperatures in two lakes was found to be subject to considerable variation throughout the year although the changes were not correlated with changes in ambient temperature. A correlation was, however, observed between temperature and ratio of number of psychrophiles to "total" count. All of the psychrophilic bacteria isolated from the studied lakes were able to grow at temperatures below 0 degrees C. Microorganisms isolated from eutrophic lakes were characterized by more pronounced stenothermy than those isolated from lake with low tropic level. These bacteria represented a type resembling a type resembling obligatory or ,,true" psychrophiles. Most of the isolates belonged to the genus Pseudomonas and to the Flavobacterium--Cytophaga group. 相似文献
18.
R. M. Wright 《Journal of fish biology》1990,36(2):215-229
The population biology of pike in two gravel pit lakes of contrasting habitat type were studied. The density of pike (1 + and over) in November 1987 in the Main Lake was 7.7 fish ha−1 (19 kg ha−1 ) and in St Peter's was 71 fish ha'(53 kg ha−1 ). The age distribution showed that recruitment was consistent in St Peter's but variable in the Main Lake. The main factor causing this difference in recruitment is abundance of aquatic vegetation. Survival up to November 1987 of 0-group pike in the Main Lake was 0.00175% from potential egg deposition, producing 6.6 fish ha−1 (0.83 kg ha−1 ). In St Peter's survival was 0.00315%, producing 23 fish ha−1 (3.04 kg ha 1 ). 相似文献
19.
20.
Linda Nedbalová Jaroslav Vrba Jan Fott Leoš Kohout Jiří Kopáček Miroslav Macek Tomáš Soldán 《Biologia》2006,61(20):S453-S465
A limnological survey of eight small, atmospherically acidified, forested glacial lakes in the Bohemian Forest (?umava, Böhmerwald) was performed in September 2003. Water chemistry of the tributaries and surface layer of each lake was determined, as well as species composition and biomass of the plankton along the water column, and littoral macrozoobenthos to assess the present status of the lakes. The progress in chemical reversal and biological recovery from acid stress was evaluated by comparing the current status of the lakes with results of a survey four years ago (1999) and former acidification data since the early 1990s. Both the current chemical lake status and the pelagic food web structure reflected the acidity of the tributaries and their aluminium (Al) and phosphorus (P) concentrations. One mesotrophic (Ple?né jezero) and three oligotrophic lakes (?erné jezero, ?ertovo jezero, and Rachelsee) are still chronically acidified, while four other oligotrophic lakes (Kleiner Arbersee, Prá?ilské jezero, Grosser Arbersee, and Laka) have recovered their carbonate buffering system. Total plankton biomass was very low and largely dominated by filamentous bacteria in the acidified oligotrophic lakes, while the mesotrophic lake had a higher biomass and was dominated by phytoplankton, which apparently profited from the higher P input. In contrast, both phytoplankton and crustacean zooplankton accounted for the majority of plankton biomass in the recovering lakes. This study has shown further progress in the reversal of lake water chemistry as well as further evidence of biological recovery compared to the 1999 survey. While no changes occurred in species composition of phytoplankton, a new ciliate species was found in one lake. In several lakes, this survey documented a return of zooplankton (e.g., Cladocera: Ceriodaphnia quadrangula and Rotifera: three Keratella species) and macrozoobenthos species (e.g., Ephemeroptera and Plecoptera). The beginning of biological recovery has been delayed for ~20 years after chemical reversal of the lakes. 相似文献