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1.
Hydrococcus brazieri and Arthritica semen on a sandflat at Coodanup,Peel Inlet, Western Australia, accounted for 89.5% of totalmollusc numbers. The mean density of H. brazieri was 9487 m2and A. semen averaged 8105 m2. H. brazieri grew at 0.5mm month1 and reached maturity in 4 months; A. semengrew at 0.3 mm month1 and reached maturity in 6 months.Somatic production in the Peel-Harvey estuarine system was estimatedto be 0.5 g m2yr1for H. brazieri and 4.1 g m2yr1for A. semen. The positions of these two species in the estuarinefoodweb is discussed. (Received 26 June 1981; 相似文献
2.
COMPARATIVE LIFE-CYCLE, BIOMASS AND SECONDARY PRODUCTION OF THREE SYMPATRIC FRESHWATER GASTROPOD SPECIES 总被引:1,自引:0,他引:1
The life cycles, biomass and secondary production of three sympatricfreshwater basommatophoran snails, Lymnaea palustris (MÜller),Physa fontinalis Linnaeus and Anisus rotundatus (Poiret) werestudied during two years in a freshwater ditch. L. palustrisexhibited an iteroparous life-cycle whereas the two other speciespresented a semelparous life-cycle, adults died just after oviposition.L. palustris secondary production (dry weight) value was higher(P = 11 298.4 mg 0.1 m1 yr1) than those of P.fontinalis (P = 846.3 mg 0.1 m2 yr1) and A. rotundatus(P = 1192 mg 0.1 m2 yr1). (Received 16 March 1992; accepted 30 June 1992) 相似文献
3.
The abundance, life span, growth and production of the mud snailsHydrobia minoricensis, H. ulvae and H. ventrosa in a semi-naturallagoon system were studied by taking monthly samples at threesites during 1991 and 1992. The most abundant species, H. minoricensisoccurred at mean densities of 12834 to 26264 snails m2(10.7 to 25.8g dry weigh m2), depending on the site.The least abundant species, H. ulvae, occurred at mean densitiesof 185 to 353 snails m2 (3.2 to 2.2g dry weight m2).The numerical abundance and biomass of the three Hydrobia specieswere positively related to the biomass of benthic macroalgae(P<0.01). Although H. ulvae egg capsules were recorded throughoutthe year, newly hatched snailsof this species were not observed,in contrast to the other two species. The early spring and summercohorts of H. minoricensis and H. ventrosa seemed to be themost numerous. The average life spans of these two species wereestimated to be about 18 and 13 months respectively. Annualproduction estimates for the whole lagoon system were 29.0 (6.3),5.5 (0.8) and 5.2 (1.0)g dry weight (ash-free dry weight) m2yr1 for H. minoricensis, H. ulvae and H. ventrosa respectively.The annual P/B ratio was about 2 for H. minoricensis and H.ventrosa. (Received 5 July 1994; accepted 5 October 1994) 相似文献
4.
Summer coastal zooplankton biomass and copepod community structure near the Italian Terra Nova Base (Terra Nova Bay, Ross Sea, Antarctica) 总被引:7,自引:0,他引:7
Pane Luigi; Feletti Mirvana; Francomacaro Barbara; Mariottini Gian Luigi 《Journal of plankton research》2004,26(12):1479-1488
The structure of the zooplankton biotic community and of copepodpopulation in the coastal area of Terra Nova Bay (Ross Sea,Antarctica) was investigated during the 10th Italian AntarcticExpedition (1994/1995). Zooplankton biotic community consistedmainly of pteropods (Limacina helicina and Clione antarctica),Cyclopoid (Oithona similis), Poecilostomatoid (Oncaea curvata)and Calanoid (Ctenocalanus vanus, Paraeuchaeta antarctica, Metridiagerlachei and Stephos longipes) copepods, ostracods, larvalpolychaetes and larval euphausiids. Zooplankton abundance rangedfrom 48.1 ind m3 to 5968.9 ind m3, and copepodabundance ranged from 45.2 ind m3 to 3965.3 ind m3.The highest peak of zooplankton abundance was observed between25 m and the surface and was mainly due to the contributionof O. similis, O. curvata and C. vanus. Zooplankton biomassranged from 5.28 mg m3 to 13.04 mg m3 dry weight;the maximum value was observed between 25 m and the surface.Total lipid content varied from 216.44 to 460.73 mg g1dry weight. 相似文献
5.
On p. 527 the legend for Table 2 should read: TABLE 2. Measured and simulated dry matter production (g m2)of Wimmera ryegrass. Data from Donald (1951) and sentence 7 in the text should read: Measured yields (averaged over four replicates and convertedto g m2), simulated yields and estimated parameters aregiven in Table 3. On p. 528 the legends for Tables 4 and 5 should read: TABLE 4. Measured and simulated dry matter production (g m2)of maize. Data from Tetio-Kagho and Gardner (1988) TABLE 5. Measured and simulated dry matter production (g m2)of lucerne. Data from Jarvis (1962), averages of four replicates,planted at two different dates in two successive years and sentence 1 should read: The maximum biomass production (A) of 113 g m2 of f.wt.corresponds with 6.3 g m2 of dry matter. 相似文献
6.
Cauchie Henry-Michel; Hoffmann Lucien; Thome Jean-Pierre 《Journal of plankton research》2000,22(12):2263-2287
The seasonal dynamics of metazooplankton biomass was monitoredin an aerated waste stabilization pond during three consecutiveyears (19941996). The pond showed a low diversity ofplanktonic metazoans because of elevated pH, relatively highconcentration of free dissolved ammonia and low oxygen concentration.The planktonic community was composed of the anomopod branchiopodDaphnia magna, and the cyclopoid copepods Cyclops vicinus andCyclops strenuus. Both predation by cyclopoids and competitionwith D.magna excluded rotifers from the pond, except duringa short period in spring 1996. Daphnia magna was the dominantorganism from a biomass point of view. In parallel with biomass,demographic parameters, secondary production and the spatialdistribution of D.magna were studied. A significant seasonaland interannual variation in the density, biomass and productionof D.magna was observed. The maximum density of daphnids variedfrom 264 x 103 to 686 x 103 individuals m2 and the maximumbiomass from 4 to 30 g dry weight (DW) m2. The annualnet production was high compared with the production of Daphniain natural environments, ranging from 288 to 593 g DW m2year1. The annual net production of exuviae accountedfor ~25% of the total annual net production. Harvesting of daphnidsfor commercial applications that took place during the productiveperiod did not have any discernible effect on the populationdynamics of D.magna. Sexual reproduction was not observed duringthe three studied years. Negative mortality rates, occurringduring early spring, however, indicated that recruitment fromephippia was effective in the pond of Differdange and that sexualreproduction took place before 1994. Swarming was regularlyobserved in relation to high densities. 相似文献
7.
Production of tropical larvaceans in Kingston Harbour, Jamaica: are we ignoring an important secondary producer? 总被引:2,自引:0,他引:2
The larvacean community was observed during an 18 month periodat the mouth of eutrophic Kingston Harbour, Jamaica. Duringthis period, larvaceans averaged 3607 m3 with a biomassof 2.2mg ash-free dry weight m3 (32.6mg AFDW m2in a community dominated by Oiko pleura longicauda There wereno relationships between larvacean biornass and any size fractionof chlorophyll, suggesting that other factors must normallyregulate larvacean communities. The evidence indicates thatthis regulation is by predation. Annual production by larvaceanswas 586 kJ m3 year 1 (29.3 g AFDW m2 year1);production of houses could represent an added 300600kJ m2 year. While copepod biomass was 10 times higherthan that of the larvaceans during the same period, copepodgrowth rates were only one.third those of larvaceans. Thus,larvacean annual production is at least 30% that of the copepods,due to their rapid growth rates, and at least 50% that of thecopepods when house production is considered. The contributionof larvaceans to plankton production has been underappreciatedhistorically when only their biomass is considered.
1Present address :Monterey Bay Aquarium Research Institute 7700Sandholdt Road, Moss Landing, CA 95039-0628, USA 相似文献
8.
On sheltered rocky beaches in Hong Kong, Linatella caudata preysupon the lower-littoral and sub-littoral fringe fauna. Ascidiantests are cut with the radula, while the proboscis is insertedbetween the parted shell valves of bivalves. The salivary glandssecrete sulphuric acid that is not used in prey penetration,as in the Cassidae, but is more likely used in digestion ordefence. In preference experiments, prey were chosen in the sequence:Barbatia virescens (Bivalvia: Arcidae) > Styela plicata (Ascidiacea)/Saccostreacucullata (Bivalvia: Ostreidae) > Lunella coronata (Gastropoda:Turbinidae) > Balanus amphitrite (Crustacea: Cirripedia).52% of all attacks were upon Barbatia Lunella and Balanus wereattacked rarely. Prey preferences by individual gastropods werealso demonstrated. Calibration plots of total weight against wet and dry tissueweight of prey (Barbatia virescens) and, finally, the predatorwere obtained and used in estimations of consumption. On average,an adult Linatella caudata (10-15g) consumed three B. virescens.week1 The mean weight of B. virescens flesh consumed.week1 ranged between 0. 2080.412g dry weight prey.gdry weight predator1, i.e., a mean of 28.2% of the predator'body weight.week1 or 4%.day1. Such a figure accordswell with estimates of consumption obtained for other adultpredatory gastropods from Hong Kong. (Received 4 September 1989; accepted 5 December 1989) 相似文献
9.
Loliun perenne L. (cv.S. 23) was grown on vermiculite in winterin a heated greenhouse for 8 weeks under factorial combinationsof two potassium regimes (nominally 6 parts/106 and 156 parts/106in Hewitt's solution) and three densities of artificially supplementedvisible radiation flux (36.1, 7.3, and 2.2 W m2). Growthand potassium uptake were studied through the calculation ofvarious growth functions from fitted curves. There was little effect of potassium treatment but the experimentalmaterial responded markedly to light. Leaf-area ratio in thethree treatments showed extreme plasticity in increasing from23 x 102 through 6 x 102 to 89 x102 m2 g1 as light intensity decreased. Correspondingdecreases in unit leaf rate, however, caused over-all reductionsin relative growth rate. Specific absorption rates for potassium (AK, dry-weight basis)were strongly reduced at the lower light intensities but alsodisplayed complex ontogenetic drifts. Values of the allometricconstant, k (the ratio of root and shoot relative growth rates),decreased from c. 0.7 at 36.1 W m2 through c. 0.3 at7.3 W m2 to a value not significantly different fromzero (P < 0.05) at 2.2 W m2. In material grown under the two higher light intensities a constantinverse relationship was found between the mass ratio of rootand shoot and the corresponding activity ratio. The resultsconform to this model: Mass ratio = 0.001+45.0 (1/activityratio) where activity ratio is expressed as specific absorptionrate for potassium (in µg g root1 h1)/unitshoot rate (rate of increase of whole-plant dry weight per unitshoot dry weight, in mg g shoot1 h1). The implicationsof this relationship are discussed. 相似文献
10.
The present study deals with structure and functioning of threeareas of Himalayan oak forest. Low- and mid-altitude oaks, namelyQuercus leucotrichophora, and Quercus floribunda, form predominantevergreen forests in Central and Western Himalaya. The totaltree basal cover ranged between 33·89 m2 ha1 (Q.floribunda site) to 36·83 m2 ha1 (Q. leucotrichophorasite). The density ranged between 570 and 760 individuals ha1.Allometric equations relating biomass of different tree componentsto GBH (girth at breast height) were significant with the exceptionof leaf biomass in Q. leucotrichophora and Rhododendron arboreum.Total vegetation biomass (29·40467·0 tha1) was distributed as 377·1 t ha1 intrees, 5·40 t ha1 in shrubs and 1·23 tha1 in herbs. Total forest floor biomass ranged between4·6 and 6·2 t ha1. Of the total annuallitter fall (4·74·8 t ha1), 77·5% was contributed by leaf litter, 17·8 % by wood litterand 4·7 % by miscellaneous litter. Turnover rate of treelitter varied from 0·66 to 0·70. Net primary productionof total vegetation ranged between 15·9 and 20·6t ha1 yr1, of which the contribution of trees,shrubs and herbs was 81·2 %, 8·6 % and 10·2%, respectively. A compartment model of dry matter on the basisof mean data across sites was developed to show dry matter storageand flow of dry matter within the system. Quercus leucotrichophora forest, Q. floribunda forest, Q. lanuginosa forest, biomass, litter fall, net primary production, compartmental transfer 相似文献
11.
Soybean [Glycine max (L.) Merrill] seeds and cotyledons weregrown in an in vitro culture system to investigate the relationshipsbetween cell expansion (net water uptake by the seed) and drymatter accumulation. Seeds or cotyledons grown in a completenutrient medium containing 200 mol m3 sucrose continueddry matter accumulation for up to 16 d after in planta seedsreached physiological maturity (maximum seed dry weight). Seedor cotyledon water content increased throughout the cultureperiod and the water concentration remained above 600 g kg1fresh weight. These data indicate that the cessation of seeddry matter accumulation is controlled by the physiological environmentof the seed and is not a pre-determined seed characteristic.Adding 600 mol m3 mannitol to the medium caused a decreasein seed water content and concentration. Seeds in this mediumstopped accumulating dry matter at a water concentration ofapproximately 550 g kg1. The data suggest that dry matteraccumulation by soybean seeds can continue only as long as thereis a net uptake of water to drive cell expansion. In the absenceof a net water uptake, continued dry matter accumulation causesdesiccation which triggers maturation. Key words: Glycine max (L.) Merrill, solution culture, duration of seed growth, water content, dry matter accumulation 相似文献
12.
The growth of lucerne var. Europe was examined in the fieldduring 1976. The annual dry matter production of unirrigatedlucerne during 1976, with no nitrogen fertilizer application,was 82.5 per cent greater than unirrigated S.24 perennial ryegrass,with a nitrogen application of 384 kg ha1. The mean aboveground growth rate of lucerne was 7.3 g DM m2 day1between March and early June, of which stem material contributeda maximum of 76.5 per cent. Significant losses of leaves andstems occurred from the end of April, indicating a loss of potentialforage material. Nitrogen analyses of the above ground crop suggested that in56 days lucerne yielded 10.7 per cent more nitrogen than didS.24 annually with a nitrogen fertilizer addition of 280 kgha1. Between 13 and 57 per cent of the daily photosynthate is translocatedbelow ground. Medicago sativaL, lucerne, dry matter production, canopy structure, nitrogen analyses 相似文献
13.
Population and individual parameters of an Italian populationof the brackish lagoon bivalve, Cerastoderma glaucum Bruguière,living in a mixohaline lagoon with typical summer dystrophy,were assessed over a one year period. Mortality and recruitmentwere both high, such that productivity and turnover were alsohigh. Individual production was considerable; one cohort achieved27 mm mean shell height and 375 mg mean dry flesh weight in9 months. Accompanying the summer dystrophy, however, most ofthe population had a very low "condition index". The reproductivecycle followed a polycyclic pattern with up to three spawningsin a single year. Circumstantial evidence suggests that thecycle is environmentally controlled, and that spawning is nota necessary consequence of gametogenic activity. The chemicalcomposition largely reflected the reproductive state and the"condition index", with large fluctuations in water, ash andglycogen contents. Calorific content also fluctuated, as a functionof ash content and lipid content; a formula is presented topredict such variation from the latter parameters. Finally,a simple production model is presented, indicating improvementsto exploit further the high productivity of these lagoons.
* Present address: Institut für Physiologische Chemie,Abt. Zellbiochemie, Universität Hamburg, Martinistrasse52, 2000 Hamburg 20, FRG (Received 6 November 1978; 相似文献
14.
Vertical distribution, life cycle and production of the chaetognath Sagitta crassa in Tokyo Bay, Japan 总被引:1,自引:0,他引:1
The daytime vertical distribution of Sagiita crassa in TokyoBay was examined from February 13, 1988 to February 20, 1989.High densities of larger-size chaetognaths were found near thesea bottom, whereas the smaller animals tended to inhabit theupper layers. This feature of distribution is discussed in relationto the distribution of their main food organisms, e g. Pseudodiaptomusmarinus, Acartia omoru, Centropages abdomialis and Oithona davisae.The two periods of replacement of two morphs were confirmedby the variation only in mean body length of this chaetognath,unlike the previous authors who made additional morphologicalobservations. It was hypothesized that S.crassa has at leastfive generations Two generations, including mostly the largerforms, had higher growth rates than the generation consistingmainly of the small form. Yearly respiration of S.crassa was8.2 g C mAbstract. Yearly production of this animal wasestimated to be 3.8 g C m. A feeding estimate revealedthat chaetognaths require a prey production of 13.1 g C myear1. The impact of this chaetognath on the prey populationin Tokyo Bay and the propriety of an estimated value of annualproduction of S crassa is discussed. 相似文献
15.
Effect of Salinity on Growth, Nodulation and Nitrogen Yield of Chickpea (Cicer arietinum L.) 总被引:2,自引:0,他引:2
Chickpea cultivar ILC 482 was inoculated with salt-tolerantRhizobium strain Ch191 in solution culture with different saltconcentrations added either immediately with inoculation or5 d later. The inhibitory effect of salinity on nodulation ofchickpea occurred at 40 dS m1 (34.2 mol m3 NaCl)and nodulation was completely inhibited at 7 dS m1 (61.6mol m3 NaCl); the plants died at 8 dS m1 (71.8mol m3 NaCl). Chickpea cultivar ILC 482 inoculated with Rhizobium strain Ch191spcstrwas grown in two pot experiments and irrigated with saline water.Salinity (NaCl equivalent to 14 dS m1) significantlydecreased shoot and root dry weight, total nodule number perplant, nodule weight and average nodule weight. The resultsindicate that Rhizobium strain Ch191 forms an infective andeffective symbiosis with chickpea under saline and non-salineconditions; this legume was more salt-sensitive compared tothe rhizobia, the roots were more sensitive than the shoots,and N2 fixation was more sensitive to salinity than plant growth. Key words: Cicer arietinum, nodulation, N2 fixation, Rhizobium, salinity 相似文献
16.
Seasonal variation of reproduction rates and body size of Calanus sinicus in the Southern Yellow Sea, China 总被引:5,自引:0,他引:5
Annual variations of egg production rate (EPR) and clutch sizeof Calanus sinicus, as well as body size of females (prosomelength and dry weight), were investigated at a series of stationsin the Southern Yellow Sea by onboard incubation. Calanus sinicuswas spawning in all the 11 cruises investigated, and the annualvariation of EPR was bimodal. Monthly average EPR was highestfrom May to July, respectively, 5.97, 5.36 and 6.30 eggs female1d1, then decreased dramatically to only 1.37 eggs female1d1 in August and attained the lowest 1.07 eggs female1d1 in October. In November, average EPR increased againto 4.31 eggs female1 d1. Seasonal variation ofclutch size was similar to EPR, except that it decreased graduallyafter August rather than dramatically as did EPR. Prosome lengthof females was maximum in May and minimum in October, but dryweight was highest in November. Monthly average EPR correlatedbetter with prosome length than dry weight, while clutch sizewas rather determined by dry weight of females. It is suggestedthat egg production of C. sinicus was active during two discontinuousperiods when both surface and bottom temperature fell into itsfavorite range (i.e. 1023°C), and different reproductivestrategies were adopted in these two reproductive peaks: otherthan the highest EPR, longer prosome length was also achievedby C. sinicus from May to July, while females in November developedshorter bodies but accumulated more energy for reproduction. 相似文献
17.
Density and distribution of bacterioplankton and planktonic ciliates in the Bering Sea and North Pacific 总被引:3,自引:0,他引:3
The total number of planktonic bacteria in the upper mixed layerof the Bering Sea during the late spring-early summer periodranged between 1 and {small tilde}4 x 106 ml1 (biomass1040mg C m3). In the northern Pacific, along 47526N,the corresponding characteristics of the bacterioplankton densityin the upper mixed water layer were: total number 12x 106 cells ml1 and biomass 1546mg C m3Below the thermocline at 50100 m, the density of bacterioplanktonrapidly decreased. At 300 m depth, it stabilized at 0.10.2x 106 cells ml1. The integrated biomass of bacterioplanktonin the open Bering Sea ranged between 1.2 and 3.6 g C m2(wet biomass 618 g m2) Its production per dayvaried from 2 to 23 mg C m3 days1 in the upper0100 m. The numerical abundance of planktonic ciliatesin this layer was estimated to be from 3 to l0 x 103 cells l1,and in the northern Pacific from 0.4 to 4.5 x 103 l2.Their populations were dominated by naked forms of Strombidium,Strombilidium and Tontonia. In some shelf areas, up to 40% ofthe total ciliate population was represented by the symbioticciliate Mesodinium rubrum. The data on the integrated biomassof basic groups of planktonic microheterotrophs are also presented,and their importance in the trophic relationships in pelagiccommunities of subarctic seas is discussed. 相似文献
18.
Umbonium vestiarium (L.) forms virtually the entire diet of3 (possibly 4) species of naticid snails and the starfish Astropectenvappa Mueller annd Troschel on some north Penang sandy shores.Umbonium comprises about 99% of numbers and tissue of macrofauna.Predation totalled some 1.75 Umbonium (ca. 33 mg dry tissue).m-2.day-1 across much of the downshore sand flats rising to 2.3Umbonium (ca. 45 mg). m-2. day-1 near MLWS. Natica maculosaLamarck comprised > 80% of the predators and took 7794%of the Umbonium eaten. Natica antonii Phillippi alone addedto this toll on the upper reaches of the zone while Polinicesspp and Astropecten appear to have taken 1214% of thetotal toll of Umbonium near MLWS. Total predation is indicatedat 237327 kJ.m-2. year-1 across the shore and this representsalmost the total flow of energy from primary consumers to intertidalbenthic predators on such shores and accounts for some 15.6%(lower shore)20.5% (upper shore) of total Umbonium production. (Received 10 September 1982; 相似文献
19.
Zooplankton in the Vasikkalampi pond, a warm water effluent recipient in Central Finland 总被引:4,自引:0,他引:4
Seasonal and vertical fluctuations of zooplankton species composition,biomass, and production were monitored by weekly sampling duringa two year period in one eutrophic pond in Central Finland.The study was one part of a more comprehensive study programto investigate the effects of warm water effluents from onesmall thermal power plant (35 MW) on the pond ecosystem. Becauseof the circulation of the pond water through the pumps in thepower plant the crustacean populations were very sparse in planktonduring the seasons the power plant was in operation (late Augustto May). During that time rotifers were dominant and some speciesreached very high densities (e.g., Keratella cochlearis s.l.ca. 15 000 ind. l1 in sping). In summer months Asplanchnapriodonta, Ceriodaphnia quadrangula, Bosmina longirostris, Mesocyclopsleuckarti and Thermocyclops oithonoides were dominant. A totalof 96 planktonic and meroplanktonic taxa were identified (26ciliates, 46 rotifers, 21 cladocerans and 3 copepods). The dryweight biomass of total zooplankton was 10 mg m3 in wintermonths, 10100 mg m3 in spring and 3001000mg m3 in summer. The total yearly production of zooplanktonwas 8552 mg dry wt m3 a1 in 1979 and 8440 mg drywt m3 a1 in 1980, from which the proportion ofrotifers was 3339%, cladocerans 5258% and copepods8.6 9.4%. The winter production was 0.20.5% ofthe total yearly production, that of spring and autumn togetherwas 8.110.4% and the remainder (8991%) was summerproduction. 相似文献
20.
The relationships between photosynthesis and photosyntheticphoton flux densities (PPFD, P-l) were studied during a red-tideof Dinophysis norvegica (July-August 1990) in Bedford Basin.Dinophysis norvegica, together with other dinoflagellates suchas Gonyaulax digitate, Ceratium tripos, contributed {small tilde}50%of the phytoplankton biomass that attained a maximum of 16.7µg Chla 1 and 11.93 106 total cells I1.The atomic ratios of carbon to nitrogen for D.norvegica rangedfrom 8.7 to 10.0. The photosynthetic characteristics of fractionatedphytoplankton (>30 µm) dominated by D.norvegica weresimilar to natural bloom assemblages: o (the initial slope ofthe P-l curves) ranged between 0.013 and 0.047 µg C [µgChla]1 h1 [µmol m s1]1the maximum photosynthetic rate, pBm, between 0.66 and 1.85µg C [µghla]1 h1; lk (the photoadaptationindex) from 14 to 69 µ,mol m2 s1. Carbonuptake rates of the isolated cells of D.norvegica (at 780 µmolm2 s1) ranged from 16 to 25 pg C cell1h and were lower than those for C.tripos, G.digitaleand some other dinoflagellates. The variation in carbon uptakerates of isolated cells of D.norvegica corresponded with PBmof the red-tide phytoplankton assemblages in the P-l experiments.Our study showed that D.norvegica, a toxigenic dinoflagellate,was the main contributor to the primary production in the bloom. 相似文献