Pub Date : 2006-09-01DOI: 10.1127/0003-9136/2006/0167-0489
M. Boersma, K. Wiltshire
Nutrient-limited algae are known to be a food source of inferior quality for zooplankters. Three factors are thought to determine this poor quality: direct elemental limitations of the algae, biochemical limitations and an increased resistance to digestion because of an increase in cell wall thickness. Thus far, most studies have concentrated on the effect of the algae on the daphniids. It has recently been hypothesized, however, that while going through the digestive tract of herbivorous zooplankters the digestion resistant nutrient-limited algae might actually take-up nutrients, in a similar way as it has been described for gelatinous alga such as Sphaerocystis. In this study, we present results of different experiments investigating whether nutrient-limited algae are indeed more resistant to digestion, and whether nutrient-limited algae take-up the limiting nutrient in the guts of their predators. We observed that digestion resistance is not very important, and that it can only be observed at high food levels. As a result, we could not find any evidence for nutrient uptake of these algae when they pass through the daphniids. We did find that animals adapted to low-P environments have a higher incorporation efficiency for P, and conclude that digestion resistance in nutrient stressed algae is of very limited ecological relevance.
{"title":"Gut passage of phosphorus-limited algae through Daphnia: do they take up nutrients in the process?","authors":"M. Boersma, K. Wiltshire","doi":"10.1127/0003-9136/2006/0167-0489","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0167-0489","url":null,"abstract":"Nutrient-limited algae are known to be a food source of inferior quality for zooplankters. Three factors are thought to determine this poor quality: direct elemental limitations of the algae, biochemical limitations and an increased resistance to digestion because of an increase in cell wall thickness. Thus far, most studies have concentrated on the effect of the algae on the daphniids. It has recently been hypothesized, however, that while going through the digestive tract of herbivorous zooplankters the digestion resistant nutrient-limited algae might actually take-up nutrients, in a similar way as it has been described for gelatinous alga such as Sphaerocystis. In this study, we present results of different experiments investigating whether nutrient-limited algae are indeed more resistant to digestion, and whether nutrient-limited algae take-up the limiting nutrient in the guts of their predators. We observed that digestion resistance is not very important, and that it can only be observed at high food levels. As a result, we could not find any evidence for nutrient uptake of these algae when they pass through the daphniids. We did find that animals adapted to low-P environments have a higher incorporation efficiency for P, and conclude that digestion resistance in nutrient stressed algae is of very limited ecological relevance.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82683331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-09-01DOI: 10.1127/0003-9136/2006/0167-0335
O. Kim, P. Junier, J. Imhoff, Karlheinz Witzel
One important pathway of the nitrogen cycle in aquatic environments is the oxidation of ammonia to nitrite by ammonia-oxidizing bacteria (AOB). In this study the composition of AOB communities was compared between fresh (lakes Plusssee and Schohsee) and brackish (Baltic Sea) water at two different levels: i) between environments and ii) within different depths in each environment. Changes in the community structure were studied by denaturing gradient gel electrophoresis (DGGE) and clone libraries of PCR products of 16S rRNA genes (rDNA) from AOB of the beta subclass of proteobacteria. Each environment displayed a particular DGGE band pattern. In Plusssee and the Baltic Sea, the differentiation of communities in epi- and metalimnion from those in hypolimnion coincided with a distinct stratification of the water column. In Schohsee with an aerobic hypolimnion, the communities at all depths were similar. AOB communities in sediments were different from those in the water column. The composition of clone libraries showed the presence of specific Nitrosomonas and Nitrosospira-like sequences in each environment and habitat.
{"title":"Comparative analysis of ammonia-oxidizing bacterial communities in two lakes in North Germany and the Baltic Sea","authors":"O. Kim, P. Junier, J. Imhoff, Karlheinz Witzel","doi":"10.1127/0003-9136/2006/0167-0335","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0167-0335","url":null,"abstract":"One important pathway of the nitrogen cycle in aquatic environments is the oxidation of ammonia to nitrite by ammonia-oxidizing bacteria (AOB). In this study the composition of AOB communities was compared between fresh (lakes Plusssee and Schohsee) and brackish (Baltic Sea) water at two different levels: i) between environments and ii) within different depths in each environment. Changes in the community structure were studied by denaturing gradient gel electrophoresis (DGGE) and clone libraries of PCR products of 16S rRNA genes (rDNA) from AOB of the beta subclass of proteobacteria. Each environment displayed a particular DGGE band pattern. In Plusssee and the Baltic Sea, the differentiation of communities in epi- and metalimnion from those in hypolimnion coincided with a distinct stratification of the water column. In Schohsee with an aerobic hypolimnion, the communities at all depths were similar. AOB communities in sediments were different from those in the water column. The composition of clone libraries showed the presence of specific Nitrosomonas and Nitrosospira-like sequences in each environment and habitat.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76652030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-09-01DOI: 10.1127/0003-9136/2006/0167-0203
R. Ortells, A. Gómez, M. Serra
In a homogeneous aquatic environment, clonal diversity in cyclical parthe- nogens should decrease with time while the population is active in the water column due to directional clonal selection. On the contrary, if planktonic populations experi- ence a heterogeneous environment the loss of clonal diversity with time could be neu- tralised. We tested the importance of these contrasting processes using ten rotifer pop- ulations belonging to four species from the Brachionus plicatilis species complex from four different ponds, and differing in their duration of the planktonic phase. Genotypic diversity and heterozygosity estimates were obtained using allozyme data. We found a negative correlation between genotypic diversity and the duration of the planktonic phase, indicating that our populations experience a homogeneous environment, and that directional clonal selection shapes the genetic structure of rotifer populations and has long-term consequences when this effect is repeated for several years. However, diversity fluctuations observed within a season suggests that the duration of the plank- tonic phase by itself is insufficient to explain the temporal dynamics of genetic divers- ity in cyclical parthenogenetic rotifers, and that there may be other factors acting on the genotypic diversity levels at a short-time scale.
{"title":"Effects of duration of the planktonic phase on rotifer genetic diversity","authors":"R. Ortells, A. Gómez, M. Serra","doi":"10.1127/0003-9136/2006/0167-0203","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0167-0203","url":null,"abstract":"In a homogeneous aquatic environment, clonal diversity in cyclical parthe- nogens should decrease with time while the population is active in the water column due to directional clonal selection. On the contrary, if planktonic populations experi- ence a heterogeneous environment the loss of clonal diversity with time could be neu- tralised. We tested the importance of these contrasting processes using ten rotifer pop- ulations belonging to four species from the Brachionus plicatilis species complex from four different ponds, and differing in their duration of the planktonic phase. Genotypic diversity and heterozygosity estimates were obtained using allozyme data. We found a negative correlation between genotypic diversity and the duration of the planktonic phase, indicating that our populations experience a homogeneous environment, and that directional clonal selection shapes the genetic structure of rotifer populations and has long-term consequences when this effect is repeated for several years. However, diversity fluctuations observed within a season suggests that the duration of the plank- tonic phase by itself is insufficient to explain the temporal dynamics of genetic divers- ity in cyclical parthenogenetic rotifers, and that there may be other factors acting on the genotypic diversity levels at a short-time scale.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76417365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-09-01DOI: 10.1127/0003-9136/2006/0167-0001
W. Gabriel
A recent model on phenotypic plasticity is extended so that reversible and irreversible plasticity can be compared. It is assumed that the plastic organism receives an environmental cue that induces a change of the phenotype. Complete and incomplete information are treated as two extreme cases of the reliability of those cues. Relative fitness is calculated depending on the difference between inducing and non-inducing states of the environment and its coefficient of variation, on the time pattern and on the relative length of the inducing environment. In addition, fitness of reversible plasticity depends on the time delays for changing the phenotype from non-induced to induced and back. Irreversible plasticity can successfully compete with reversible plasticity only if at least one of these time delays becomes large, irrespective of the reliability of environmental cues. For either complete or incomplete information, there are parameter regions in which irreversibility is advantageous.
{"title":"Selective advantage of irreversible and reversible phenotypic plasticity","authors":"W. Gabriel","doi":"10.1127/0003-9136/2006/0167-0001","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0167-0001","url":null,"abstract":"A recent model on phenotypic plasticity is extended so that reversible and irreversible plasticity can be compared. It is assumed that the plastic organism receives an environmental cue that induces a change of the phenotype. Complete and incomplete information are treated as two extreme cases of the reliability of those cues. Relative fitness is calculated depending on the difference between inducing and non-inducing states of the environment and its coefficient of variation, on the time pattern and on the relative length of the inducing environment. In addition, fitness of reversible plasticity depends on the time delays for changing the phenotype from non-induced to induced and back. Irreversible plasticity can successfully compete with reversible plasticity only if at least one of these time delays becomes large, irrespective of the reliability of environmental cues. For either complete or incomplete information, there are parameter regions in which irreversibility is advantageous.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87477266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-09-01DOI: 10.1127/0003-9136/2006/0167-0467
J. Grover, T. Chrzanowski
, Abstract: A stoichiometric approach is applied to model nutrient element content and population growth kinetics in phagotrophic flagell~tes. Available evidence is limited, but suggests that the nutrient composition of flagellates is not strictly homeostatic, but instead varies with the nutrient element composition of their food resources. A mathe- matical model is constructed that couples the C, N, and P contents of flagellates to their population growth rate and the nutrient fluxes assimilated from food resources. Variants of the model are explored to examine the effects of saturating ingestion, main- tenance respiration, and selective feeding from food mixtures. In agreement with observations, the models predict non-homeostatic variation in the nutrient content of flagellates. Population growth rate is predicted to vary with both food quantity and quality (in terms of nutrient element content). It is proposed that lack of homeostasis and selective feeding on prey with high nutrient content enhance fitness of pha- gotrophic flagellates under some conditions.
{"title":"Stoichiometry and growth kinetics in the \"smallest zooplankton\" - phagotrophic flagellates","authors":"J. Grover, T. Chrzanowski","doi":"10.1127/0003-9136/2006/0167-0467","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0167-0467","url":null,"abstract":", Abstract: A stoichiometric approach is applied to model nutrient element content and population growth kinetics in phagotrophic flagell~tes. Available evidence is limited, but suggests that the nutrient composition of flagellates is not strictly homeostatic, but instead varies with the nutrient element composition of their food resources. A mathe- matical model is constructed that couples the C, N, and P contents of flagellates to their population growth rate and the nutrient fluxes assimilated from food resources. Variants of the model are explored to examine the effects of saturating ingestion, main- tenance respiration, and selective feeding from food mixtures. In agreement with observations, the models predict non-homeostatic variation in the nutrient content of flagellates. Population growth rate is predicted to vary with both food quantity and quality (in terms of nutrient element content). It is proposed that lack of homeostasis and selective feeding on prey with high nutrient content enhance fitness of pha- gotrophic flagellates under some conditions.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88367559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-09-01DOI: 10.1127/0003-9136/2006/0167-0593
B. Manly, M. Chotkowski
There is currently a good deal of concern about a recently recognized decline in the numbers of several pelagic fish species in the Sacramento-San Joaquin Delta in California, USA. Several research groups are investigating possible reasons for this decline. One part of this study addresses whether the decline is the result of some recent regime change in the ecosystem, and more generally whether one or more regime changes have occurred since regular sampling of fish, zooplankton and mysids shrimps began in 1967. There are many statistical methods of analysis that have been proposed to detect regime changes. These are reviewed, but it is noted that none of them is immediately suitable for analysing the basic data collected from the Sacramento-San Joaquin Delta, which consists of counts from trawl hauls and other sampling gears used in the field. Two new methods are therefore proposed for this type of data, which is commonly collected. One method searches for times when the mean level and trend in the abundance of an organism changed, assuming that in the absence of a regime change the abundances will exhibit a linear trend with time. The other method assumes that in the absence of a regime change the abundances will exhibit a polynomial trend in time, and searches for times when the mean level changed significantly. Both methods rely on bootstrap resampling of the data for assessing the significance of apparent regime changes. Simulation studies to verify the properties of the proposed analyses are described, and also some examples of the results of the analyses on the Sacramento-San Joaquin data.
{"title":"Two new methods for Regime Change Analyses","authors":"B. Manly, M. Chotkowski","doi":"10.1127/0003-9136/2006/0167-0593","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0167-0593","url":null,"abstract":"There is currently a good deal of concern about a recently recognized decline in the numbers of several pelagic fish species in the Sacramento-San Joaquin Delta in California, USA. Several research groups are investigating possible reasons for this decline. One part of this study addresses whether the decline is the result of some recent regime change in the ecosystem, and more generally whether one or more regime changes have occurred since regular sampling of fish, zooplankton and mysids shrimps began in 1967. There are many statistical methods of analysis that have been proposed to detect regime changes. These are reviewed, but it is noted that none of them is immediately suitable for analysing the basic data collected from the Sacramento-San Joaquin Delta, which consists of counts from trawl hauls and other sampling gears used in the field. Two new methods are therefore proposed for this type of data, which is commonly collected. One method searches for times when the mean level and trend in the abundance of an organism changed, assuming that in the absence of a regime change the abundances will exhibit a linear trend with time. The other method assumes that in the absence of a regime change the abundances will exhibit a polynomial trend in time, and searches for times when the mean level changed significantly. Both methods rely on bootstrap resampling of the data for assessing the significance of apparent regime changes. Simulation studies to verify the properties of the proposed analyses are described, and also some examples of the results of the analyses on the Sacramento-San Joaquin data.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88491680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-09-01DOI: 10.1127/0003-9136/2006/0167-0371
T. Weisse
Similar to Daphnia, many planktonic ciliates are algivores that occur in vir- tually every natural lake and reproduce primarily asexually. Due to their larger popula- tion size and shorter generation time, their significance as algal consumers and second- ary producers may exceed that of Daphnia during algal blooms and when averaged over the season. The high reproduction rate, the ease of culturing, the accessibility to experimental manipulation, and the potential to apply sophisticated measuring techni- ques such as flow cytometry render some ciliate species ideal candidates for ecophy- siological laboratory experiments. This paper summarizes recent research in which ciliates have been used as model organisms for investigating the effect of environ- mental key parameters on planktonic organisms. Special attention is given to the (com- bined) effect of temperature, food, pH and predators. Niche partitioning has been stud- ied at the level of genus, species and clone. Open questions and emerging perspectives of ciliate research for issues of general ecological relevance will be discussed at the end of each section.
{"title":"Freshwater ciliates as ecophysiological model organisms - lessons from Daphnia, major achievements, and future perspectives","authors":"T. Weisse","doi":"10.1127/0003-9136/2006/0167-0371","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0167-0371","url":null,"abstract":"Similar to Daphnia, many planktonic ciliates are algivores that occur in vir- tually every natural lake and reproduce primarily asexually. Due to their larger popula- tion size and shorter generation time, their significance as algal consumers and second- ary producers may exceed that of Daphnia during algal blooms and when averaged over the season. The high reproduction rate, the ease of culturing, the accessibility to experimental manipulation, and the potential to apply sophisticated measuring techni- ques such as flow cytometry render some ciliate species ideal candidates for ecophy- siological laboratory experiments. This paper summarizes recent research in which ciliates have been used as model organisms for investigating the effect of environ- mental key parameters on planktonic organisms. Special attention is given to the (com- bined) effect of temperature, food, pH and predators. Niche partitioning has been stud- ied at the level of genus, species and clone. Open questions and emerging perspectives of ciliate research for issues of general ecological relevance will be discussed at the end of each section.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90746089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-08-01DOI: 10.1127/0003-9136/2006/0166-0505
P. Saglio, Anne-Lise Mandrillon
Amphibians are known to exhibit phenotypic plasticity in response to variations in predation pressure. Data also indicate that developmental changes can be induced by embryonic exposures to predator non-contact cues. However, the possible consequences of such exposures on larval behavioural activity and sensitivity to chemical cues from predators have remained unexplored. These laboratory experiments examine the effects of predation cues experienced during embryonic development on some morphological and behavioural traits in hatchlings and tadpoles of the common frog (Rana temporaria). Eggs were raised until hatching in the nonlethal presence of either a sympatric predator (larval spotted salamander, Salamandra salamandra), or an allopatric predator (juvenile Turkish crayfish, Astacus leptodactylus), or crushed conspecific tadpoles. Predators were kept either starved, or fed with R. temporaria tadpoles. Embryonic treatments had significant consequences on weight and total length of hatchlings, as well as on the general activity of tadpoles. Olfactometric tests showed that the behavioural responses of tadpoles to chemical cues from the two predators tested were not significantly affected by embryonic treatments. In contrast, embryonic experience showed a significant influence on the behavioural response of tadpoles to chemical cues from crushed conspecifics. These results indicate that the morphology of hatchlings depends on the species and diet of the predators present during embryonic development and demonstrate for the first time that the subsequent activity and chemically mediated antipredator behaviour of tadpoles can be influenced by embryonic experience of the predation risk.
{"title":"Embryonic experience to predation risk affects tadpoles of the common frog (Rana temporaria)","authors":"P. Saglio, Anne-Lise Mandrillon","doi":"10.1127/0003-9136/2006/0166-0505","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0505","url":null,"abstract":"Amphibians are known to exhibit phenotypic plasticity in response to variations in predation pressure. Data also indicate that developmental changes can be induced by embryonic exposures to predator non-contact cues. However, the possible consequences of such exposures on larval behavioural activity and sensitivity to chemical cues from predators have remained unexplored. These laboratory experiments examine the effects of predation cues experienced during embryonic development on some morphological and behavioural traits in hatchlings and tadpoles of the common frog (Rana temporaria). Eggs were raised until hatching in the nonlethal presence of either a sympatric predator (larval spotted salamander, Salamandra salamandra), or an allopatric predator (juvenile Turkish crayfish, Astacus leptodactylus), or crushed conspecific tadpoles. Predators were kept either starved, or fed with R. temporaria tadpoles. Embryonic treatments had significant consequences on weight and total length of hatchlings, as well as on the general activity of tadpoles. Olfactometric tests showed that the behavioural responses of tadpoles to chemical cues from the two predators tested were not significantly affected by embryonic treatments. In contrast, embryonic experience showed a significant influence on the behavioural response of tadpoles to chemical cues from crushed conspecifics. These results indicate that the morphology of hatchlings depends on the species and diet of the predators present during embryonic development and demonstrate for the first time that the subsequent activity and chemically mediated antipredator behaviour of tadpoles can be influenced by embryonic experience of the predation risk.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76100538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-08-01DOI: 10.1127/0003-9136/2006/0166-0565
C. Schelske, F. J. Aldridge, H. Carrick, M. Coveney
{"title":"Net production and heterotrophy in Lake Apopka: a reply to BACHMANN et al.","authors":"C. Schelske, F. J. Aldridge, H. Carrick, M. Coveney","doi":"10.1127/0003-9136/2006/0166-0565","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0565","url":null,"abstract":"","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87115214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-08-01DOI: 10.1127/0003-9136/2006/0166-0433
C. Leboulanger, Catherine Quiblier, P. Dufour
An approach is described here that has been designed to determine the fac- tors that control growth and standing crop in natural populations of phytoplankton. This approach involves the use of 1) small volume bioassays of natural phytoplankton samples, incubated in semi-natural conditions, 2) indirect determination of phyto- plankton biomass during growth by in vivo chlorophyll-a fluorescence measurements, and 3) computer-designed factorial plans. A commercial computer program was used to achieve optimal planning of the assays, statistically sound and rapid data analysis, and forecasting of phytoplankton responses to inputs. An example of field application of the protocol is described, in which a phytoplankton population of a Western African Lake was studied. This approach can be used to rapidly identify the main bottom-up control factors and their interactions, and further refining of analysis with optimization of sample number. Modelled responses also make it possible to predict how phyto- plankton biomass would change in reaction to changes in environmental conditions. The pros and cons of the approach are discussed taking into account the use of frac- tional design and the reduction of sample numbers.
{"title":"Rapid assessment of multiple-limiting factors of phytoplankton biomass : bioassays, in vivo chlorophyll-a fluorescence, and factorial design","authors":"C. Leboulanger, Catherine Quiblier, P. Dufour","doi":"10.1127/0003-9136/2006/0166-0433","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0433","url":null,"abstract":"An approach is described here that has been designed to determine the fac- tors that control growth and standing crop in natural populations of phytoplankton. This approach involves the use of 1) small volume bioassays of natural phytoplankton samples, incubated in semi-natural conditions, 2) indirect determination of phyto- plankton biomass during growth by in vivo chlorophyll-a fluorescence measurements, and 3) computer-designed factorial plans. A commercial computer program was used to achieve optimal planning of the assays, statistically sound and rapid data analysis, and forecasting of phytoplankton responses to inputs. An example of field application of the protocol is described, in which a phytoplankton population of a Western African Lake was studied. This approach can be used to rapidly identify the main bottom-up control factors and their interactions, and further refining of analysis with optimization of sample number. Modelled responses also make it possible to predict how phyto- plankton biomass would change in reaction to changes in environmental conditions. The pros and cons of the approach are discussed taking into account the use of frac- tional design and the reduction of sample numbers.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90610765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：