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1.
Chebotareva MA Zabelinskiĭ SA Shukoliukova EP Krivchenko AI 《Zhurnal evoliutsionno? biokhimii i fiziologii》2011,47(5):383-387
Comparative study of fatty acid composition of total phospholipids, as well as of phosphatidylcholine and phosphatidylethanolamine from hepatopancreas and leg muscle was performed on several representatives of gasteropods (Gastropoda) molluscs and bivalve (Bivalvia) mussel (Mytilus edulus). The objects of our study were marine litorins (Littorina saxsatilis) adapted to different temperature conditions of White Sea and Barents Sea, freshwater lymnaea (Lymnaea stagnalis) infested by Trematoda and mussels from White Sea and Black Sea. It was shown that depending on the existence conditions of studied tissue or lipid, the maximal change is observed in the percentage of saturated acids (4-83 %), the percentage of unsaturated acids was less expressed (1-14 %) and the changes in unsaturation index (UI) did not exceed 20 % on average. It was supposed that observed quantitative bounds of UI change under the action of different external factors is utmost for maintenance of membrane fluidity necessary for normal vital activity of cell, particularly in studied ectothermic molluscs. 相似文献
2.
Dynamics of Mya arenaria beds in two bights of the Chupa Inlet (Kandalaksha Bay, White Sea) were studied on a long-term basis. Observations were carried
out at 1– to 3-year intervals from 1979 up to 1999. The studied soft-shell clam beds were characterised by a substantial instability
of age structure. Since 1988, only one year-class has dominated in the beds while other generations have been scarce and recruitment
was not observed. This pattern of Mya bed dynamics was related neither to interannual environmental changes nor to differential reproduction success or predation
effects in the benthic assemblages. Favourable conditions for spat formation in 1988 (low abundance of other M. arenaria generations), as well as for juvenile survival during the following winter, resulted in high abundance of juveniles in both
investigated locations in 1989. The mortality rate (μ) in this 1988 generation varied throughout the period of investigation and was related to age. The mortality level decreased
for the first 2–4 years of the life cycle, then stabilised for the next 3–4 years, and eventually increased in subsequent
years. Overall μ values ranged from 0 to 1.68 year–1. The oldest specimens observed were 17 years old and had a maximum shell length of 79 mm. Significant differences in average
growth rates were observed between molluscs of different locations.
Communicated by H.-D. Franke 相似文献
3.
Dopamine- and noradrenaline-induced modifications of outward potassium currents were studied in identified neurons of the
lesser parietal ganglion of adult (10–12 months) and old (22–24 months) molluscsLimnaea stagnalis. In the neurons of old molluscs, 2·10−5 M dopamine made activation of potassium channels of delayed current 2.5 times more frequent than in adult molluscs. Noradrenaline
(5·10−5 M) significantly increased delayed outward potassium currents in adult molluscs and did not modify these currents in old
molluscs. It is supposed that there are age-related modifications of the ratio between the active and passive components of
potassium ion transport in the mechanism responsible for monoamine-induced reactions of a neuron. 相似文献
4.
The horizontal heterogeneity of common zooplankton species in the Keretskaya Guba tidal estuary in the White Sea was studied.
Based on an analysis of a series of simultaneously taken samples and the dispersion index, I
w
= σ2/[`(m)]\bar{m} (where σ2 is dispersion and [`(m)]\bar{m} is average population number), the existence of two and more levels of aggregation in most of the studied zooplankton species
was found. The formation of patches of 1–20 m was most likely determined by biological causes, while patches some hundreds
of meters long were formed due to the hydrodynamic conditions of the area. 相似文献
5.
Based on the data from long-term observations on the development of fouling communities of mussel culture farms in the White
Sea, an analysis of dynamics of population density of common polychaete species was carried out. The expansion of the polychaete
Lepidonotus squamatus for the past 9 years was recorded. Cyclic variations of population density were revealed practically in all studied species.
The duration of the period of these cycles varied from 7–8 years (L. squamatus and Amphitrite cirrata), 11–14 years (Nereis pelagica, Harmothoe imbricata, Eulalia viridis, Neoamphitrite figulus) and even about 20 years (Nereimyra punctata and Capitella capitata). Observable periodic variations in the abundance of polychaetes apparently were not related to long-term fluctuations of
water temperature. 相似文献
6.
Romuald Czerpak Andrzej Bajguz Marta Gromek Grażyna Kozłowska Izabela Nowak 《Acta Physiologiae Plantarum》2002,24(1):45-52
This study was conducted to investigate the influence of salicylic acid (SA) on the growth and changes of nucleic acids, protein,
photosynthetic pigments, sugar content and photosynthesis levels in the green alga Chlorella vulgaris Beijerinck (Chlorophyceae). The most significant changes in the content of nucleic acids and proteins was observed at the concentration 10−4 M SA between 8 and 12 day of cultivation. This concentration of SA increased the number of cells (about 40 %) and content
of proteins (about 60 %) and its secretion to the medium. The slight stimulation of protein secretion occurred on the 12th
day of cultivation at concentration 10−4 M, while in the range of 10−5 M to 10−6 M the protein secretion was inhibited. SA also stimulated the content of nucleic acids, especially RNA by 20–60 %, compared
with the control. The most stimulating influence upon the contents of chlorophylls a and b (50–70 %), total carotenoids (25–57 %), sugar (27–41 %) and intensity of net photosynthesis (18–33 %) was found at 10−4 M of SA. At the concentration of 10−6 M SA the slight inhibition of growth and biochemical activity of the algae was recorded at the first days of cultivation. 相似文献
7.
A. Sommer B. Klein H. O. Pörtner 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(1):25-35
Temperature dependent changes in the mode of energy metabolism and in acid-base status were studied in the range from −1.7
to 26 °C in two populations of Arenicola marina collected in summer as well as in winter from intertidal flats of the North Sea (boreal) and the White Sea (subpolar). Extreme
temperatures led to an accumulation of anaerobic end products, indicating the existence of both a low and a high critical
temperature, beyond which anaerobic metabolism becomes involved in energy production. In summer animals from the North Sea
the high critical temperature was found at temperatures above 20 °C, and the low critical temperature below 5 °C. Latitudinal
or seasonal cold adaptation lead to a more or less parallel shift of both high and low critical temperature values to lower
values. Between critical temperatures intracellular pH declined with rising temperature. Slopes varied between −0.012 and
−0.022 pH- units/°C. In summer animals from the North Sea, the slope was slightly less than in White Sea animals, but differences
appeared independent of the season. However, slopes were no longer linear beyond critical temperatures. A drop in intracellular
pH at low temperatures coincided with the accumulation of volatile fatty acids in the body wall tissue of North Sea animals.
A failure of active pHi adjustment is held responsible for the reduced ΔpHi/ΔT at temperatures above the high critical temperature. Extracellular pH was kept constant over the whole temperature range
investigated. The ability of North Sea animals to adapt to temperatures beyond the critical temperature is poor compared to
White Sea specimens. The larger range of temperature fluctuations at the White Sea is seen as a reason for the higher adaptational
capacity of the subpolar animals. A hypothesis is proposed that among other mechanisms critical temperature values are set
by an adjustment of mitochondrial density and thus, aerobic capacity.
Accepted: 20 August 1996 相似文献
8.
C. Calderón J. Lacey A. McCartney I. Rosas 《International journal of biometeorology》1997,40(2):71-80
The effect of an urban climate upon the spatial and temporal distribution of Deuteromycete spores was studied during 1991
using Burkard volumetric spore traps in two areas of Mexico City with different degrees of urbanization. Deuteromycete conidia
formed the largest component of the total airborne fungal spore load in the atmosphere of Mexico City, contributing 52% of
the spores trapped in an urban-residential area (southern area) and 65% of those in an urban-commercial area (central area).
Among the most common spore types, Cladosporium and Alternaria showed a marked seasonal periodicity with significant differences in concentration (P<0.05) between the dry and wet seasons. Maximum conidial concentrations were found during the end of the wet season and the
beginning of the cool, dry season (October–December). Daily mean concentrations of the predominant airborne spore types did
not differ significantly between the southern and central areas. Daily mean spore concentrations were significantly correlated
(P<0.05) in southern and central areas with maximum temperature (south, r = –0.35; central, r = –0.40) and relative humidity (south, r = 0.43; central, r = 0.29) from the previous day. Moreover, multiple regression analysis of spore concentrations with several meteorological
factors showed significant interactions between fungal spores, relative humidity and maximum temperature in both areas. The
diurnal periodicity of Cladosporium conidia characteristically showed two or three peaks in concentration during the day at 0200–0400, ∼ 1400 and 2000–2200 hours,
while that of Alternaria showed only one peak (1200 to 2000 hours) in both areas. Maximum concentrations of these spores generally occurred 2–4 h earlier
in the southern than in the central area. The lag in reaching maximum concentrations in the central area probably resulted
from differences in the local conditions between the study areas, and from spores transported aerially into the city from
distant sources. The analysis of maximum hourly concentrations of Cladosporium and Alternaria spores during 1 month of the dry season (February), and another month of the wet season (September) showed significant differences
between the two study areas. Environmental factors and sources (green areas) affected diurnal changes in conidial concentration
in the southern area (urbanization index, UI, 0.25), but not in the central area (UI 0.97). In general, spore concentrations
were greatest in the southern area when relative humidities were low, and temperatures and wind velocities were high. It was
difficult to establish effects of climatic factors on the spore concentration in the city centre. This probably results from
the large amounts of air pollution, the heat island phenomenon, and from the distant origin of trapped conidia obviating aerial
transport. Nevertheless, the seasonal and diurnal distributions of conidia found were similar to those reported for other
tropical regions of the world.
Received: 13 August 1996 / Accepted: 4 December 1996 相似文献
9.
Brandon K. Swan James M. Watts Kristen M. Reifel Stuart H. Hurlbert 《Hydrobiologia》2007,576(1):111-125
The Salton Sea currently suffers from several well-documented water quality problems associated with high nutrient loading.
However, the importance of phosphorus regeneration from sediments has not been established. Sediment phosphorus regeneration
rates may be affected by benthic macroinvertebrate activity (e.g. bioturbation and excretion). The polychaete Neanthes
succinea (Frey and Leuckart) is the dominant benthic macroinvertebrate in the Salton Sea. It is widely distributed during periods
of mixing (winter and spring), and inhabits only shallow water areas following development of anoxia in summer. The contribution
of N. succinea to sediment phosphorus regeneration was investigated using laboratory incubations of cores under lake temperatures and dissolved
oxygen concentrations typical of the Salton Sea. Regeneration rates of soluble reactive phosphorus (SRP) were lowest (−0.23–1.03
mg P m−2 day−1) under saturated oxygen conditions, and highest (1.23–4.67 mg P m−2 day−1) under reduced oxygen levels. N. succinea most likely stimulated phosphorus regeneration under reduced oxygen levels via increased burrow ventilation rates. Phosphorus
excretion rates by N. succinea were 60–70% more rapid under reduced oxygen levels than under saturated or hypoxic conditions. SRP accounted for 71–80% of
the dissolved phosphorus excreted under all conditions. Whole-lake SRP regeneration rates predicted from N. succinea biomass densities are highest in early spring, when the lake is mixing frequently and mid-lake phytoplankton populations
are maximal. Thus, any additional phosphorus regenerated from the sediments at that time has potential for contributing to
the overall production of the lake.
Guest Editor: John M. Melack
Saline Water and their Biota 相似文献
10.
Daria M. Martynova Natalia A. Kazus Ulrich V. Bathmann Martin Graeve Alexey A. Sukhotin 《Polar Biology》2011,34(8):1175-1195
We have studied the seasonal dynamics of abundance and feeding characteristics of three species of calanoid copepods (Acartia spp., Centropages hamatus and Temora longicornis) in the White Sea from the surface water layer (0–10 m), in order to assess their role in the pelagic food web and to determine
the major factors governing their population dynamics during the productive season. These species dominated in the upper water
layer (0–10 m) from June through September, producing up to 3 generations per year. Data on the food spectra revealed all
species to be omnivorous; but some inter- and intraspecific differences were observed. Generally, copepods consumed diatoms,
dinoflagellates and microzooplankton. The omnivory index ‘UC’ (i.e., fatty acid unsaturation coefficient) varied from 0.2
to 0.6, which implied ingestion of phytoplankton. The different degree of selectivity on the same food items by the studied
species was observed, and therefore, successful surviving strategy with minimal overlapping could be assumed. In total, the
populations of the three studied copepod species grazed up to 2.15 g C m−2 day−1 and released up to 0.68 g C m−2 day−1 in faecal pellets. They consumed up to 50% of particulate organic carbon, or up to 85% of phytoplankton standing stock (in
terms of Chl. a), and thus played a significant role in the transformation of particulate organic matter. Seasonal changes in abundance of
the studied species depended mostly on water temperature in the early summer, but were also affected by food availability
(Chl. a concentration) during the productive season. 相似文献
11.
Seasonal changes in fatty acid composition associated with cold-hardening in third instar larvae of Eurosta solidaginis 总被引:1,自引:1,他引:0
Valerie A. Bennett Nancy L. Pruitt Richard E. Lee Jr. 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(4):249-255
Third-instar larvae of the goldenrod gall fly Eurosta solidaginis (Diptera: Tephritidae) survive extended periods in winter during which tissue water is frozen. Both low temperature and reduced
water activity during freezing present challenges for the structural integrity of cellular lipids. Fatty acids of both phospholipids
and triacylglycerols from fat body cells of E. solidaginis were analyzed throughout fall and early winter, a period that encompasses the acquisition of freeze-tolerance, to determine
if adaptations to freezing include changes in fatty acid unsaturation. The five most abundant fatty acids from both fractions
were (in decreasing order) oleic (40–65%), palmitoleic (18–20%), palmitic (12–17%), linoleic (5–10%), and stearic acids (4 –7%).
This represents a typical complement of Dipteran fatty acids, although oleic acid levels were higher in E. solidaginis than those reported from other Dipterans (˜28%; Downer 1985). From September to November, monounsaturates increased from
59 to 70% in phospholipids at the expense of saturated fatty acids (25% –20%) suggesting activation of a Δ9-desaturase enzyme. These changes resulted in an increase in the ratio of unsaturated to saturated fatty acids (U/S) from
3.0 to 4.2, although there was no change in the average number of double bonds per fatty acid (unsaturation index, UI ≈ 1.2
in phospholipids and 0.9 in triacylglycerols throughout the season). These changes were temporally correlated to decreasing
ambient temperatures and increasing larval and fat body cell freeze-tolerance.
Accepted: 31 October 1996 相似文献
12.
Salton Sea, California, like many other lakes, has become eutrophic because of excessive nutrient loading, primarily phosphorus
(P). A Total Maximum Daily Load (TMDL) is being prepared for P to reduce the input of P to the Sea. In order to better understand
how P-load reductions should affect the average annual water quality of this terminal saline lake, three different eutrophication
programs (BATHTUB, WiLMS, and the Seepage Lake Model) were applied. After verifying that specific empirical models within
these programs were applicable to this saline lake, each model was calibrated using water-quality and nutrient-loading data
for 1999 and then used to simulate the effects of specific P-load reductions. Model simulations indicate that a 50% decrease
in external P loading would decrease near-surface total phosphorus concentrations (TP) by 25–50%. Application of other empirical
models demonstrated that this decrease in loading should decrease near-surface chlorophyll a concentrations (Chl a) by 17–63% and increase Secchi depths (SD) by 38–97%. The wide range in estimated responses in Chl a and SD were primarily caused by uncertainty in how non-algal turbidity would respond to P-load reductions. If only the models
most applicable to the Salton Sea are considered, a 70–90% P-load reduction is required for the Sea to be classified as moderately
eutrophic (trophic state index of 55). These models simulate steady-state conditions in the Sea; therefore, it is difficult
to ascertain how long it would take for the simulated changes to occur after load reductions.
Guest editor: S. H. Hurlbert
The Salton Sea Centennial Symposium. Proceedings of a Symposium Celebrating a Century of Symbiosis Among Agriculture, Wildlife
and People, 1905–2005, held in San Diego, California, USA, March 2005. 相似文献
13.
Tamar Feldstein Yoel Kashman Avigdor Abelson Lev Fishelson Ofer Mokady Vladimir Bresler Yigal Erel 《Helgoland Marine Research》2003,57(3-4):157-165
The study reported here is part of an ongoing effort to establish sensitive and reliable biomonitoring markers for probing the coastal marine environment. Here, we report comparative measurements of a range of histological, cellular and sub-cellular parameters in molluscs sampled in polluted and reference sites along the Mediterranean coast of Israel and in the northern tip of the Gulf of Aqaba, Red Sea. Available species enabled an examination of conditions in two environmental 'compartments': benthic (Donax trunculus) and intertidal (Brachidontes pharaonis, Patella caerulea) in the Mediterranean; pelagic (Pteria aegyptia) and intertidal (Cellana rota) in the Red Sea. The methodology used provides rapid results by combining specialized fluorescent probes and contact microscopy, by which all parameters are measured in unprocessed animal tissue. The research focused on three interconnected levels. First, antixenobiotic defence mechanisms aimed at keeping hazardous agents outside the cell. Paracellular permeability was 70–100% higher in polluted sites, and membrane pumps (MXRtr and SATOA) activity was up to 65% higher in polluted compared to reference sites. Second, intracellular defence mechanisms that act to minimize potential damage by agents having penetrated the first line of defence. Metallothionein expression and EROD activity were 160–520% higher in polluted sites, and lysosomal functional activity (as measured by neutral red accumulation) was 25–50% lower. Third, damage caused by agents not sufficiently eliminated by the above mechanisms (e.g. single-stranded DNA breaks, chromosome damage and other pathological alterations). At this level, the most striking differences were observed in the rate of micronuclei formation and DNA breaks (up to 150% and 400% higher in polluted sites, respectively). The different mollusc species used feature very similar trends between polluted and reference sites in all measured parameters. Concentrating on relatively basic levels of biological organization—the molecular and cellular level—the parameters measured may have the capacity not only for biomonitoring environmental quality, but also for early warning.Communicated by H. von Westernhagen, A. Diamant 相似文献
14.
Inter-annual variability in the diet of Chinstrap penguins (Pygoscelis antarctica) at Laurie Island (South Orkney Islands) and 25 de Mayo/King George and Nelson Islands (South Shetland) was examined based
on stomach contents of adults during the 2002/2003–2006/2007 and 2002/2003–2004/2005 breeding seasons, respectively. Krill
(Euphausia superba) dominated the diet as frequency of occurrence (in 100% of samples), number (>99%), and percentage contribution in weight
(>94.8%). Other prey items were minor and varied between years. The weight of stomach contents was significantly different.
The percentage in weight of whole krill was used to compare the feeding conditions across seasons. It differed significantly
at the three sites studied. Distribution of krill size varied among years and localities, showing different krill availability
for penguins. 相似文献
15.
R. L. Wolff Bernard Comps Anne M. Marpeau Laurent G. Deluc 《Trees - Structure and Function》1997,12(2):113-118
The fatty acid compositions of the seed oils from ten pine species have been established by capillary gas-liquid chromatography
of the methyl esters. With regard to either normal fatty acids or Δ5-olefinic acids, the general pattern of fatty acids did
not differ from that of other pine seed oils reported previously. The main fatty acid was linoleic (9,12–18:2) acid (44.4–57.1%),
followed by either oleic (9–18:1) acid (13.4–24.5%) or pinolenic (5,9,12–18:3) acid (1.5–25.2%). When applying multivariate
analyses to the chemometric data (13 variables) of 49 pine species (ca. 40% of the living pine species), it was possible to
distinguish between several sections: Pinea, Longifolia, Halepensis, Ponderosa-Banksiana, Sylvestris, and Cembra. The latter section was clearly divided into two sub-groups. A few species that presented a low overall content of Δ5-olefinic
acids, and that grow in warm-temperate regions, were isolated from the bulk of other pine species. It is hypothesized that
Δ5-olefinic acids might be related to cold-acclimation.
Received: 5 June 1997 / Accepted: 17 August 1997 相似文献
16.
A. N. Stroganov K. I. Afanas’ev K. E. Jorstad M. Storr-Paulsen A. M. Orlov G. A. Rubtsova T. A. Rakitskaya 《Journal of Ichthyology》2011,51(9):738-744
Comparative analysis of variability of seven microsatellite loci—Gmo3, Gmo-G12, Gmo-G18, Gmo19, Gmo34, Gmo35 and Pgmo32—was performed for the Greenland cod Gadus ogac, Pacific cod G. macrocephalus, Atlantic cod G. morhua, and White Sea cod G. morhua marisalbi. High genetic identity was observed between the Greenland cod and Pacific cod (I = 0.9520). Pair analysis of genetic differentiation
was performed on the studied microsatellite loci according to θ (analogue of F
ST). The Greenland cod differed significantly from the Pacific, Atlantic, and the White Sea cod; however, the differentiation
level varied. The lowest value was observed for the pair Greenland cod-Pacific cod (0.123), and the highest levels were registered
for the pairs Greenland cod-Atlantic cod (0.605) and Greenland cod-White Sea cod (0.535). 相似文献
17.
Resistance to freshwater exposure in White Sea Littorina spp. I: Anaerobic metabolism and energetics
Sokolova IM Bock C Pörtner HO 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2000,170(2):91-103
Anaerobic metabolism and changes in the osmotic concentration of extravisceral fluid were studied in the White Sea periwinkles
(Littorina littorea, Littorina saxatilis and Littorina obtusata) during freshwater exposure. Resistance to hypoosmotic stress increased in the order: L. obtusata < L. saxatilis < L. littorea. Our data suggest that osmotic shock is not a primary reason for mortality of the periwinkles under these conditions. During
environmental anaerobiosis, considerable succinate accumulation (up to 10–19 μmol g−1 wet weight), and depletion of phosphagen and ATP pools were found in the studied species. Other metabolic end products (alanopine,
strombine, lactate, acetate or propionate) were not detected. Succinate accumulation and net ATP breakdown were the fastest
in the least resistant species, L. obtusata, and slowest in the most resistant, L. littorea. Rate of ATP turnover decreased during freshwater exposure in L. littorea and L. saxatilis, but not in L. obtusata. Our data suggest that differential resistance of three studied Littorina spp. to extreme hypoosmotic stress may be related to their different abilities to reduce metabolic rate and ATP turnover
during sustained anoxia. Species-specific variations in anaerobic capacity of Littorina spp. are discussed in relation to their vertical distribution, size and ecology.
Accepted: 4 October 1999 相似文献
18.
Lenka Vojtíšková Edita Munzarová Olga Votrubová Hana Čížková Helena Lipavská 《Hydrobiologia》2006,563(1):73-85
Carbon and nitrogen balance in Acorus calamus, a wetland species colonising littoral zones with a high trophic status, was studied under experimental conditions using
water or sand culture with a defined composition of the nutrient solution. Influence of graded level of N (1.86, 7.5 and 18.6
mM) and/or forms of N (NH4+ versus NO 3–) on the content of non-structural carbohydrates, free amino acids, total C, and total N was studied in Acorus rhizomes and roots to find possible connection with a reduced growth of Acorus plants under high N and NH4+–N nutrition described in our previous study [Vojtíšková et al., 2004. Hydrobiologia 518: 9–22]. High N availability and pure
NH4+–N nutrition affected the C/N balance of rhizome and root systems of Acorus in a similar way. NH4+–N was the only form of N elevated under the high N treatment. The major proportion of the total non-structural carbohydrates
(TNC) was starch (91–93% and 51–64% in rhizomes and roots, respectively). The content of starch was significantly and and
negatively affected by high N availability (P = 0.001), as well as by NH4+–N nutrition (P=0.001). Amounts of simple soluble carbohydrates (sucrose, glucose, and fructose) were negligible in comparison to starch
in rhizomes and branched roots (up to 5% of TNC), while roots without developed lateral roots (unbranched) contained up to
33% of TNC in the form of simple soluble sugars. Moreover, high hexoses/sucrose ratio, low starch/soluble sugars ratio, high
content of N, and low C/N ratio support the notion that unbranched roots are metabolically active young roots with tissue
differentiation in progress. A high content of free amino acids, typically with dominance of N-rich amino acids (Arg-46%,
Gln-8%, Asn-7%), was found simultaneously with a low carbohydrate content under high N supply, which indicates that NH4+ received is effectively incorporated into the organic form by this species. Since the decrease in carbohydrate content was
not accompanied by luxurious growth, other possible carbon consuming processes were discussed in relation to NH4+ nutrition. More dramatic changes in total N than C were found under high N availability resulting a shift in C/N ratio in
favour of N. Although the shift towards N metabolism was obvious, no serious carbohydrate depletion occurred, which could
explain the reduced growth of Acorus plants under high N and sole NH4+–N nutrition described previously. 相似文献
19.
The biodiversity and spatial distribution of macrofauna biomass are studied for 12 sites of stonesand littoral in the Neva
Estuary in 2002–2005. The highest biodiversity has been observed for chironomids and oligochaetes in the Neva Bay (36% and
24% of total species number) and in the eastern Gulf of Finland (33% and 23%). Amphipods (≤89%), molluscs (≤61%), and chironomids
(≤37%) dominate by biomass. The biomass spatial distribution vary dramatically from 9 to 37 g m−2 in the freshwater Neva Bay and from 1 to 68 g m−2 for the other Neva Estuary areas. The bottom fauna biomass in the Neva Bay is significantly lower than in the 1980–1990’s
and constitutes 20–50% of the biomass previously observed. We explain such a significant decrease by a reduction of the insects
and aborigine crustaceans Gammarus lacustris Sars and Asellus aquaticus L. The invasive amphipod species Gmelinoides fasciatus (Stebbing) dominated by biomass for the study period (3.8–15.6 g m−2, or >30% of total macrozoobenthos biomass). 相似文献
20.
Growth and emission characteristics of the luminescent bacterium Photobacterium phosphoreum strain KM MGU 331 originating from the White Sea and isolated from the intestine of a bottom-dwelling fish, the European
sculpin, Myoxocephalus scorpius, were analyzed. The strain is characterized by a high rate of colony formation and high intensity of light emission on agarized
medium at 4° C as well as by highly efficient (5 × 105 quanta s−1 cell−1) and prolonged (over 100 h) light generation upon submerged cultivation at 20°C. The acidic shift of pH in the medium didn’t
exceed 0.3 pH units. Effects of temperature, pH, and sodium chloride concentration on emission characteristics of intact photobacterium
cells were studied. The optimal temperature for luminescence was found to be 15°C. The maximum luminescence activity was stable
in a wide pH range from 7.0 to 9.0. Luminescence occurred within the range of 0.2–3.8% NaCl with the maximum at 2.5%. The
results obtained confirm the literature data suggesting that luminescent bacteria adapted to low-temperature conditions possess
a highly conjugated system of electron transfer to luciferase. 相似文献