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1.
Miralto A.; Ianora A.; Guglielmo L; Zagami G.; Buttino I. 《Journal of plankton research》1998,20(12):2369-2378
In situ rates of egg production and hatching success are reportedfor Calanus simillimus, one of the most abundant calanoid speciesin peri-Antarctic regions, during the Italian Italicscruise in the Straits of Magellan in March-April 1995. Low fecundity(8.6 eggs female1 day1) and fecal pellet production(0.8 fecal pellets female1 day1) in this periodindicate that the species was feeding very poorly. Sixty-sixof the 126 females sampled did not produce eggs and 80 of thesedid not produce any fecal pellets during the 24 h period ofincubation. Striking abnormal naupliar and embryonic developmentwas recorded in 81.8% of the eggs spawned. Aberrant eggs didnot undergo normal cleavage, and failed to develop to hatching.Deformed nauplii were asymmetrical and presented strong anatomicalanomalies in the total body length and number of swimming appendages.These results are discussed in the light of recent findingson the causes of low hatching success in copepods. 相似文献
2.
Jonasdottir Sigrun H.; Trung Nguyen Huu; Hansen Frank; Gartner Sanne 《Journal of plankton research》2005,27(12):1239-1259
Spatial and seasonal egg production rates (Er) and egg hatchingsuccess in the copepods Calanus finmarchicus and Calanus helgolandicuswere measured in the North Sea from March to September. Foodavailability was monitored by chlorophyll and protist concentrationsand three size fractions of seston fatty acids. Seasonal andspatial distribution and production differed between the species.Calanus finmarchicus was found only offshore of the 50-m isobath,with decreasing Er (3728 eggs female1 day1)from March to July. Calanus helgolandicus had two abundancepeaks, in spring and autumn, with a low in May during whichtime the highest Er were observed (38 eggs female1 day1).At other times, Er in C. helgolandicus remained lower than inC. finmarchicus ( 相似文献
3.
Egg production rates (EPRs) of Calanus euxinus were measuredin the Black Sea during October 2000 and May 2001. EPRs weregenerally low, on average 1.7 eggs female1 day1in October 2000 and 3.9 eggs female1 day1 in May2001. The relationships between EPRs and gonad maturity, depth-integratedchlorophyll a (Chl a) and mean surface layer temperature wereexamined. The EPRs were not related to depth-integrated Chla, but were negatively correlated with temperature. EPRs werestrongly related to the proportion of mature females. Growthrates of C. euxinus were derived from the EPRs. The mean growthrate was 0.011 day1 in October 2000 and 0.03 day1in May 2001. Growth rates were not significantly correlatedwith Chl a concentrations, but were negatively related to femaleweight and temperature. 相似文献
4.
Egg production by the calanoid copepods Calanoides carinatusand Calanus agulhensis fed excess Thalassiosira weissflogiiwas monitored in the laboratory following starvation periodsof 1, 3, 5, 7 and 9 days. Following short (13 day) periodsof starvation, egg production by C.agulhensis returned to thesatiated rate (51.1 eggs {female} day1) more rapidly(after 0.92.4 days of excess food) than that of Ca. carinatus(after 2.83.1 days). However, following longer (59day) periods of starvation, Ca. carinatus regained satiatedlevels of egg production (55.8 eggs {female}1 day1)more rapidly (after 3.14.0 days of excess food) thanC. agulhensis (after 3.85.2 days of feeding following57 days of starvation). Moreover, many C. agulhensisfemales did not regain normal rates of egg production after9 days of starvation. For both species, the time required foregg production to recover was proportional to the starvationperiod, although only up to 7 days for C. agulhensis, and wasthe same following 4.25 days of starvation. Previously fed Ca.carinatus terminated egg production more rapidly than C. agulhensiswhen starved. The ability of Ca. carinatus to tolerate, andrecover rapidly from, prolonged periods of starvation, combinedwith a comparatively fast development time and high rate ofegg production, provides this species with a strong competitiveadvantage over C. agulhensis in the highly pulsed food environmentof the southern Benguela upwelling region. 相似文献
5.
Peterson William T.; Painting Suzanne J.; Hutchings Laurence 《Journal of plankton research》1990,12(2):259-281
The gut fluorescence technique was used to estimate ingestionand filtration rates of the adult female copepods Paracalanusparvus, Cenlropages brachiatus and Calanus austrails, and copepoditestages 3, 4 and 5 of C.australis in the southern Benguela upwellingregion. During the study period chlorophyll concentrations withinthe upper 20 m of the water column were high, 5 µg I1in mid-shelf waters and 1530 µg I1 in innershelf waters. Copepod gut pigment content was low and constantduring the day then increased sharply during the first 2 h aftersunset. Gut pigment content was 26 times higher duringthe night compared with daytime values. Small non-migratingcopepods (Paracalanus parvus) showed the smallest diel differencein gut pigment content and large migrating copepods (Centropagesbrachiatus and Calanus australis) the largest difference. Eggproduction rates were 20 and 50% of maximum at the mid-shelfand inner shelf stations respectively, suggesting food-limitation.Comparison of ingestion rates calculated from egg productiondata with ingestion rates calculated from gut pigment data suggestedthat the copepods were feeding omnivorously at the inner shelfstations but herbivorously at the mid-shelf stations. Assumingthat all of the phytoplankton was available as food, the nearshorecopepod assemblage grazed {small tilde}1% of the standing cropeach day, and the mid-shelf assemblage grazed 5% day1.Because of errors and uncertainties associated with the gutfluorescence technique, the feeding impact could be underestimatedby 24-fold. We discuss several approaches which couldlead to more precise estimates of feeding rates.
3Present address: Marine Sciences, SUNY, Stony Brook, NY, 11794-5000,USA 相似文献
6.
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
7.
We measured egg production rates of the estuarine calanoid copepodAcartia tonsa in Mobile Bay, an estuary in the northern Gulfof Mexico. Two stations were sampled approximately monthly,one at the mouth of the bay and the other just beyond the mouthin the salinity front between bay and coastal waters. Over thewhole year, temperature was the most important environmentalvariable controlling egg production. Rates increased with temperatureup to 30°C and 140 eggs female1 day1. We foundno evidence of food limitation. There was no correlation betweenegg production and phytoplankton abundance, nor increased eggproduction in response to supplements of phytoplankton addedto natural food, suggesting that non-phytoplankton food wasimportant in the diet. At the highest egg production rates,the amount of the storage lipid triacylglycerol (TAG) in adultfemales was greatly diminished, to <50 ng female1.This suggests that lipids in the diet can be very tightly coupledto egg production. Both egg production and TAG content of femalesshowed significant variability on spatial scales of 315km, especially in relation to the salinity front separat ingwater outwelling from the bay from open coastal water. For organismsthat are using copepods and their eggs as food, this variabilitywould result in a heterogeneous food environment, both in termsof the abundance of food and its nutritional content. 相似文献
8.
Copepod egg production, moulting and growth rates, and secondary production, in the Skagerrak in August 1988 总被引:5,自引:0,他引:5
Peterson William T.; Tiselius Peter; Kiorboe Thomas 《Journal of plankton research》1991,13(1):131-154
Measurements of hydrography, chlorophyll, moulting rates ofjuvenile copepods and egg production rates of adult female copepodswere made at eight stations along a transect across the Skagerrak.The goals of the study were to determine (i) if there were correlationsbetween spatial variations in hydrography, phytoplankton andcopepod production rates, (ii) if copepod egg production rateswere correlated with juvenile growth rates, and (iii) if therewas evidence of food-niche separation among co-occumng femalecopepods The 200 km wide Skagerrak had a stratified water columnin the center and a mixed water column along the margins. Suchspatial variations should lead to a dominance of small phytoplanktoncells in the center and large cells along the margins; however,during our study blooms of Gyrodinium aureolum and Ceratium(three species) masked any locally driven differences in cellsize: 50% of chla was >11 µm, 5% in the 1150µm fraction and 45% <50 µm. averaged for allstations. Chlorophyll ranged from 0.2 to 2.5 µg l1at most depths and stations. Specific growth rates of copepodsaveraged 0.10 day1 for adult females and 0.27 day1for juveniles The latter is similar to maximum rates known fromlaboratory studies, thus were probably not food-limited. Eggproduction rates were food-limited with the degree of limitationvarying among species: 75% of maximum for Centropages typicus, 50% for Calanus finmarchicus, 30% for Paracalanus parvus and 15% for Acartia longiremis and Temora longicornis. Thedegree of limitation was unrelated to female body size suggestingfood-niche separation among adults. Copepod production, summedover all species, ranged from 3 to 8 mg carbon m3day1and averaged 4.6 mg carbon m1 day1. Egg productionaccounted for 25% of the total. 相似文献
9.
The in situ predation rate of the siphonophore Sphaeronectesgracilis was estimated from gut content analysis of hand-collectedsiphonophores and from laboratory data on digestion rates ofprey organisms. At daytime prey densities of 0.25 copepods 11,S. gracilis was estimated to consume 8.1 15.4 prey day1siphonophore1. From data on abundances of siphonophoresand copepods, S. gracilis was estimated to consume 24%of the copepods daily. In laboratory experiments, ingestionrates averaged 13.8 prey day1 siphonophore1 atprey densities of 5 copepods 11 and 36.9 at 20 copeods11. This was equivalent to a specific ingestion rate(for both carbon and nitrogen) of 17% day1 and45% day1, respectively, while specific ingestion in situwas only 2% day1. Ammonium excretion averaged 0.095 µg-atsiphonophore1 day1 at 5 prey 11, and 0.162at 20 prey 11. The specific respiration (carbon) andspecific excretion (nitrogen as ammonium) were calculated tobe 3% day1 at the lower experimental food level, and5% day1 at the higher food level.
1Contribution from the Catalina Marine Science Center No. 66.
2Present address: Dept. of Biology, University of Victoria,Victoria, B.C., Canada V8W 2Y2. 相似文献
10.
Mayor Daniel J.; Anderson Thomas R.; Irigoien Xabier; Harris Roger 《Journal of plankton research》2006,28(12):1167-1179
Simultaneous ingestion and egg production experiments were conductedwith female Calanus finmarchicus in April/May and July/August2002 in the Irminger Sea. Experimental animals were providedwith natural microplankton food assemblages and incubated underin situ conditions for 24 h. The quantity of food consumed wassignificantly related to the concentration of prey cells, withtotal daily ingestion rates ranging from 0.6 to 8.1 µgof carbon female1 day1, corresponding to carbon-specificrates of 0.64.7% day1. Egg production rates (EPRs)remained relatively low (0.311 eggs female1 day1)during both periods of investigation and were not influencedby food availability. The data were used to construct energeticbudgets in which the microplankton carbon ingested, includingciliates, was compared with the carbon utilized for egg productionand respiration. These budgets showed that ingestion alone couldnot provide the necessary carbon to sustain the observed demandsfor growth and metabolism. Although ciliates constituted >80%of the total material ingested at times, they were not sufficientto provide the metabolic shortfall. Indeed, the females weretypically lacking 5 µg of carbon each day, 5% of theircarbon biomass. Our study results highlight the possible importanceof internal reserves in sustaining reproduction in C. finmarchicusduring periods of food scarcity. 相似文献
11.
Egg production, growth and development rates of Oithona similiswere measured in the laboratory as a function of food concentrationand composition. On an optimum diet, development is isochronaland growth is near exponential. The maximum juvenile growthrate at 15C (0.2 day1) is similar to juvenile growthin calanoid copepods. The maximum weight-specific egg productionrate (0.1 day1), on the other hand, is substantiallyless than in free-spawning calanoids, but similar to that inegg-carrying calanoids. In the Kattegat, Oithona spp. egg productionis strongly limited by food during summer and controlled bytemperature during winter. The seasonal signal in fecundityand population biomass is much weaker than in the co-occurringfree-spawning calanoid genera, where fecundity and populationbiomass undergo dramatic seasonal viaration.
1Present address: Instituto Nacional de Investigacin y DesarrolloPesquero, INIDEP, CC 175, Playa Grande, Mar del Plata, Argentina 相似文献
12.
Production of Penilia avirostris in Kingston Harbour, Jamaica 总被引:2,自引:0,他引:2
The cladoceran Penilia avirostris is one of the more abundantand widespread members of the crustacean zooplankton in nearshoretropical and subtropical waters. Its abundance, biomass, fecundity,development rate and production were estimated in Kingston Harbour,Jamaica, during an 18 month period. Mean annual abundance ofPenilia was 1821 m3, while biomass (excluding eggs/embryos)was 2.87 mg ash-free dry-weight (AFDW) m3 (43.1 mg AFDWm2), accounting for 13% of the copepod community biomass.Fecundity increased with body size. There was no clear seasonalpattern of abundance, size or fecundity, nor were physical orbiological variables correlated to these variations. Developmenttime averaged 20.5 h for juveniles and 41.4 h for adult femalesduring incubations; there was no clear evidence of a diel patternto molting. Growth rate appeared to be exponential, with correspondingsomatic growth rates, averaging 0.27 day1 for juveniles,and 0.34 day1 for somatic plus reproductive growth inadult females. Annual production was estimated as 173 kJ m2year1, 相似文献
13.
Biomass, feeding and production of Noctiluca scintillans in the Seto Inland Sea, Japan 总被引:1,自引:0,他引:1
The abundance and biomass of the large heterotrophic dinoflagellateNoctiluca scintillans, together with the changes in its potentialprey items, were monitored in the Seto Inland Sea, Japan, duringsummer 1997 (17 July-11 August). Growth and grazing rates ofNscintillans fed natural plankton populations were also measuredeight and seven times, respectively, during the survey period.The abundance and biomass of N scintillans averaged over thewater column (19 m) were in the range 1345 cells 11(temporalaverage = 93 cell11) and 0.149.6 µg C l1(temporalaverage = 13.8 µg C l1; three times higher thanthat of calanoid copepods during the same period). Noctilucascintillans populations followed the changes in phytoplankton:N.scintillans biomass was increasing during the period of diatomblooms and was at a plateau or decreasing during periods oflow chlorophyll a. The growth rates of N.scintillans (µ)were also consistent with the wax and wane of the N.scintillanspopulation: N.scintillans showed highest growth rates duringdiatom blooms. A simple relationship between µ and chlorophylla concentration was established, and the production of N.scintillanswas estimated using this relationship and the measured biomass.The estimated production averaged over the water column wasin the range >0.15.2 µg C l1 day1(temporalaverage = 1.4 µg C l1 day1; 64% of the productionof calanoid copepods during the same period). Diatom clearancerates by N.scintillans were in the range 0.100.35 mlcell1 day1, and the phytoplankton population clearanceby N.scintillans was >12% day1. Thus, although thefeeding pressure of N.scintillans on phytoplankton standingstock was low, N.scintillans was an important member of themesozooplank-ton in terms of biomass and production in the SetoInland Sea during summer. 相似文献
14.
Halsband-Lenk C.; Nival S.; Carlotti F.; Hirche H.-J. 《Journal of plankton research》2001,23(6):597-609
Reproduction of the dominant copepods Centropages typicus andTemora stylifera was studied at a permanent station in the LigurianSea (north-western Mediterranean). Seasonal patterns of eggproduction, clutch size, egg size and female prosome lengthwere followed from January 1998 to December 1999. Female carboncontent and weight-specific egg production were compared inautumn 1998 and spring 1999. Reproductive patterns of C. typicusand T. stylifera were very similar, indicating that reproductionwas affected by the same environmental factors. Reproductiveactivity was highest in autumn in both species and years. Asecond peak of egg production was observed in early summer,which was less intense in 1999 after a bloom of salps. Egg productionrates reached maximal values of 33.5 and 33.3 eggs female1day1 and annual means of 10.8 and 11.7 eggs female1day1 in Centropages and Temora, respectively. Maximalweight-specific egg production was 0.21 day1 in bothspecies in November 1998, when female carbon contents were 6.7(C. typicus) and 12.0 µg (T. stylifera). No statisticalrelationship between egg production and food availability ortemperature was detected. Reproductive activity did not reflectthe seasonal abundance patterns, with C. typicus dominatingin spring and T. stylifera in autumn. 相似文献
15.
Napp Jeffrey M.; Hopcroft Russell R.; Baier Christine T.; Clarke Cheryl 《Journal of plankton research》2005,27(5):415-426
Pseudocalanus species are important contributors to the secondaryproduction of the northern hemisphere mid- to high-latitudeoceans. In the coastal Gulf of Alaska, Pseudocalanus are presentyear round and are represented by three species. In 2001, Pseudocalanusmimus was the dominant Pseudocalanus species on the shelf duringspring and summer, comprising 30100% of the total, whilePseudocalanus newmani dominated in Prince William Sound (1090%).Pseudocalanus minutus were only abundant in Prince William Soundduring early spring. Egg production (by number and volume) wasa function of female prosome length and decreased from springto summer; however, significant variability was attributableto regional influences that were independent of size. For thesame sized female, P. newmani produced more eggs per clutchthan P. mimus. Pseudocalanus mimus, however, tended to havea larger mean egg size than P. newmani. Consequently, clutchvolumes of the two species were indistinguishable. Pseudocalanusegg production rates (EPRs) (eggs female1 day1)were lower in July and August (ca. 24) than April andMay (ca. 19), but total egg production by the population(eggs day1) was nearly equivalent for the two time periodsdue to higher female concentrations in summer. 相似文献
16.
Specific growth rates of heterotrophic plankton organisms in a eutrophic lake during a spring bloom 总被引:2,自引:0,他引:2
The in situ growth of the dominating pelagic organisms at severaltrophic levels was investigated during a spring bloom characterizedby well-mixed cold water. The study includes primary productionand the carbon flow through the nano-, micro- and mesozooplanktonpopulations based on population dynamics and specific growthrates. The phytoplankton biomass and production were totallydominated by small algae <20 µm. of which {small tilde}5%were <3µm. potentially a food source for the nano-and microzooplankton. The mean carbon-specific primary productionwas 0.15 day1 and was regulated solely by light. Themean volume-based specific growth rate of bacterioplankton wasmodest. 0.1 day1. and probably controlled by the lowtemperature. The volume-based specific growth rates of heterotrophicnanoflagellates. ciliates. rotifers and copepods were 0.35.0.13. 0.16 and 0.03 day1, respectively. The observedgrowth of the heterotrophic plankton was generally not foodlimited, but was controlled by temperature. The stable temperatureduring the experiment therefore allows a cross-taxonomic comparisonof specific growth rates. The b exponent in the allometric relationship(G = aVth) between volume-specific growth rate (G) and individualbody size (V) was 0.15 ± 0.03 for all filtratingzooplankton. indicating an in situ scaling not far from thephysiological principles onginally demonstrated for laboratorypopulations. 相似文献
17.
Centropages abdominalis is a neritic, omnivorous, temporallyabundant copepod present throughout the subarctic Pacific andits marginal seas. The two main objectives of this study wereto determine how temperature influences the development of C.abdominalis and whether growth rates of in situ populationsmay be limited by available food. At 6.9°C, median developmenttime from eggs laid to 50% adults was 42 days and the averageweight-specific somatic growth rate was 0.17 day1. At4.6°C, median development time to adult was 59 days (projected)and growth rate averaged 0.08 day1, suggesting that 4.6°Cmay be approaching the lower temperature for development andgrowth in this species. The functional relationship betweendevelopment time and temperature was established over the temperaturerange in which this species occurs. The in situ adult growthrates between 10 and 13°C averaged 0.14 day1 andwere generally lower than the laboratory-reared juvenile growthrates, which may indicate that adult C. abdominalis are foodlimited in the field during summer and autumn. 相似文献
18.
Resting egg production and oviducal cycling were investigatedfor the calanoid copepods Arctodiaptomus alpinus and Acanthodiaptomusdenticornis both in the laboratory and in a small karstic alpinelake by making a census of the number of eggs produced and theproportion of females in each of four morphologically distinguishedreproductive conditions each day in the laboratory or duringa 23 week period in lake enclosures. In the laboratory,individuals were maintained on a mixed diet of natural phytoplanktonat constant temperatures of 4, 10, 15 and 20C, respectively.Both species differed considerably in their temperature requirementsfor reproduction. Lifetime fecundity was highest at 10C in A.alpinusand at 20C in A.denticornis, with up to 327 eggs 1 spawnedin the former and up to 582 eggs 1 in the latter species.Unfavorable temperatures were further reflected in an increasein egg mortality and the allocation of time spent in a post-reproductivephase, as well as in a decrease of longevity. Increasing temperaturesenhanced egg production rates due to decreasing clutch productionperiods, although clutch size was negatively correlated withtemperature. Maximum rates reached 5.88 and 7.98 eggs 1day1 in the laboratory, and 0.73 and 0.55 eggs 1day1 in enclosures in A.alpinus and A.denticornis, respectively.Egg production rates and clutch size were clearly governed bynutritional conditions in the lake, but were less affected byfood supply in the laboratory. Here, rates of egg productionwere adapted to improving food supply by increasing the frequencyof spawning events, rather than the number of eggs per clutch.No correlation was found between female body size and reproductiveparameters in the laboratory. A very low proportion of totalclutch production resulted in clutches composed of subitaneouseggs, i.e. 0.14% in A.denticornis and 1.20% in A.alpinus. Oviducalphase duration allocations indicate that there exists a temperatureoptimum for gamete maturation. 相似文献
19.
The juvenile growth rates and development times of subarcticCalanus marshallae and temperate/sub-tropical C. pacificus wereinvestigated during nine cruises (May through October, 200104)in the northern Gulf of Alaska. The artificial cohort methodbased on a length-weight regression was used for growth estimatesand the reciprocal of the molting rate for developmental time.The copepodite stage duration ranged from 3 to 16 days for C.marshallae (C1C4) and 323 days for C. pacificus(C1C5). Seasonally, copepodid growth rates increasedfrom May to October, ranging between 0.055 and 0.291 day1(mean ± SE: 0.176 ± 0.008 day1) for C.marshallae, while growth rates increased from August to Octoberbetween 0.018 and 0.296 day1 (mean ± SE: 0.142± 0.016 day1) for C. pacificus. After standardizationto 5°C (Q10 of 2.7), growth rate averaged 0.118 ±0.007 day1 and 0.075 ± 0.009 day1 for C.marshallae and C. pacificus, respectively. Calanus marshallaegrowth rate is satisfactorily described by a MichaelisMentenmodel using chlorophyll-a concentration (r2 = 0.33) after temperaturecorrection, but the prediction improves with a composite nonlinearmodel combining body weight into the MichaelisMentenfunction (r2 = 0.55). Considering the limited range of dataavailable for C. pacificus, the combination of the data forboth species suggests that C. pacificus has a similar functionalresponse to growth despite the differences in the geographicand temporal distributions with C. marshallae. Measured juvenilegrowth rates of the two Calanus species in this study were comparableto other calanoid species in the same area and showed reasonableagreement to Calanus growth models but less with global copepodgrowth models. 相似文献
20.
The growth of heterotrophic nanoflagellates (HNF) in mesotrophicLake Constance was measured in situ during a 13 month period.Experiments were conducted with 10 µm pre-filtered lakewater incubated in diffusion chambers at 3 m water depth atthe sampling location for 24 h. Growth rates were calculatedfrom changes in cell numbers occurring during the period ofincubation. Growth rates of all dominant taxa showed pronouncedseasonal variation (0.13 to 1.76 day1 and weregenerally highest in summer at high water temperatures. In situgrowth rates were well below maximum growth rates known forthe respective and similar species from laboratory experiments.While water temperature was a key parameter positively relatedto the growth of all HNF species, the effect of various potentialfood items was taxon specific and less clear. Bacterial abundancewas equally important as temperature for growth in the smallbactenvorous Spumella sp., but was insignificant for growthrates of the larger omnivorous Kathablepharis sp. In Spuniellasp., 84% of the observed seasonal variation of its growth ratecould be explained by temperature and bacterial food supply.Based on these results, a multiple linear regression equationwith temperature and bacterial concentration as dependent variableswas calculated for the growth rate of Spumella. Taxon-specificproduction rates were derived from growth rates and averagebiomass of these two species, and compared to total HNF productionestimated from previously measured community growth rates andbiomass in Lake Constance. Production peaks of Spumella sp.and Kathablepharis sp. alternated seasonally. Total HINF productionranged from 0.01 to 10 mg C m3 day1. Theaverage seasonal production varied between 1.4 and 33 mg C m3day1 over 6 consecutive years. These small protozoa thuscontribute a substantial amount to total zooplankton productionin Lake Constance. 相似文献