Pub Date : 2006-08-01DOI: 10.1127/0003-9136/2006/0166-0453
L. Boyero, R. Pearson, R. Camacho
Forested headwater streams are detritus-based systems where shredder activity is usually crucial, but information on the role of different species on ecosystem function is very limited, especially in the tropics. We investigated the roles of the four most common shredder species on leaf breakdown in two tropical Australian streams by (1) studying variation in their abundance between seasons and habitat types, (2) relating their abundance to in situ leaf breakdown rates, (3) determining their leaf breakdown rates in the laboratory, and (4) comparing their niche characteristics. The species differed in their abundance, seasonal and spatial variation, leaf breakdown rates and other characteristics, suggesting different roles in the ecosystem: Lectrides varians was the most abundant species in pools in both the dry and wet season, and also the fastest processor, suggesting a particularly strong influence of this species on leaf breakdown; Anisocentropus kirramus appeared to have an important role in riffles, being the only shredder species found in that habitat; Triplectides gonetalus predominated in patches of small woody material, and used wood as food; and Atalophlebia sp. was important as both a collector and a shredder in pools. Our results suggest each species has a different role in the ecosystem, having an important function in a specific habitat or microhabitat, or showing some differentiation in resource use. This implies that the effect of species loss on ecosystem functioning would be more dependent on the identity, rather than the number, of the species that are lost.
{"title":"Leaf breakdown in tropical streams: the role of different species in ecosystem functioning","authors":"L. Boyero, R. Pearson, R. Camacho","doi":"10.1127/0003-9136/2006/0166-0453","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0453","url":null,"abstract":"Forested headwater streams are detritus-based systems where shredder activity is usually crucial, but information on the role of different species on ecosystem function is very limited, especially in the tropics. We investigated the roles of the four most common shredder species on leaf breakdown in two tropical Australian streams by (1) studying variation in their abundance between seasons and habitat types, (2) relating their abundance to in situ leaf breakdown rates, (3) determining their leaf breakdown rates in the laboratory, and (4) comparing their niche characteristics. The species differed in their abundance, seasonal and spatial variation, leaf breakdown rates and other characteristics, suggesting different roles in the ecosystem: Lectrides varians was the most abundant species in pools in both the dry and wet season, and also the fastest processor, suggesting a particularly strong influence of this species on leaf breakdown; Anisocentropus kirramus appeared to have an important role in riffles, being the only shredder species found in that habitat; Triplectides gonetalus predominated in patches of small woody material, and used wood as food; and Atalophlebia sp. was important as both a collector and a shredder in pools. Our results suggest each species has a different role in the ecosystem, having an important function in a specific habitat or microhabitat, or showing some differentiation in resource use. This implies that the effect of species loss on ecosystem functioning would be more dependent on the identity, rather than the number, of the species that are lost.","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":"86936190","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: 10.1127/0003-9136/2006/0166-0525
H. Golterman
The presence of polyphosphates and inositol phosphates (a. o. phytate) remains a much-discussed subject in limnological literature. Their determination is not yet undisputed, and several of the methods used are not very good. Therefore I have reviewed existing methodology and suggested some improvements. These include anion exchange chromatography for phytate analysis and extraction with trichloroacetic acid for polyphosphates analysis. The subject is important, as polyphosphates are metabolically active, while phytate is much less so and may even accumulate in sediments in which much FeOOH is present.
{"title":"Reviewing problems and possibilities for the analysis of phytate and polyphosphates","authors":"H. Golterman","doi":"10.1127/0003-9136/2006/0166-0525","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0525","url":null,"abstract":"The presence of polyphosphates and inositol phosphates (a. o. phytate) remains a much-discussed subject in limnological literature. Their determination is not yet undisputed, and several of the methods used are not very good. Therefore I have reviewed existing methodology and suggested some improvements. These include anion exchange chromatography for phytate analysis and extraction with trichloroacetic acid for polyphosphates analysis. The subject is important, as polyphosphates are metabolically active, while phytate is much less so and may even accumulate in sediments in which much FeOOH is present.","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":"78537052","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: 10.1127/0003-9136/2006/0166-0491
J. A. Santmire, L. Leff
Few studies have documented temporal changes in bacterial communities in multiple habitats in streams. In this year long study in the West Branch of the Mahoning River in Northeast Ohio, USA, bacteria in water, leaves, and sediments were examined. Bacteria were enumerated using 4,6-diamidino-2-phenylindole (DAPI) and fluorescent in situ hybridization (FISH) using taxon-specific probes for the Domain Bacteria and Burkholderia cepacia. Physical and chemical variables were also monitored. Total bacterial abundance in water (based on DAPI staining) peaked during October 2000 and July 2001; while on leaves, total abundance peaked in January then declined through April with a second June peak. The peak in sediments was during October 2000 and numbers did not differ significantly between a pool and a riffle. Domain Bacteria numbers also exhibited significant temporal changes but the seasonal patterns differed from those based on DAPI staining. Abundance of B. cepacia varied temporally on leaves but not in water and sediments. Contrary to other studies, no significant correlations were seen between bacteriological and physical/chemical variables measured. However, spring run off seems to have been a factor in temporarily reduced numbers on leaves and sediments and increasing bacterioplankton numbers, likely due to allochthonous inputs. Based on prior studies, we expected the pattern of temporal change in bacterial numbers to vary among habitats. However, there were no differences between pool and riffle sediments and no significant correlations between bacteriological and abiotic variables. This may reflect the ability of bacteria to persist under varying temperature/nutrient conditions and flow regimes. The ability of B. cepacia to maintain fairly constant populations, in contrast to the overall assemblage, likely reflects the extreme versatility of this organism.
{"title":"Temporal Changes in the Bacterial Assemblage of a Northeast Ohio Stream: A Comparison of Community and Population-Level Responses","authors":"J. A. Santmire, L. Leff","doi":"10.1127/0003-9136/2006/0166-0491","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0491","url":null,"abstract":"Few studies have documented temporal changes in bacterial communities in multiple habitats in streams. In this year long study in the West Branch of the Mahoning River in Northeast Ohio, USA, bacteria in water, leaves, and sediments were examined. Bacteria were enumerated using 4,6-diamidino-2-phenylindole (DAPI) and fluorescent in situ hybridization (FISH) using taxon-specific probes for the Domain Bacteria and Burkholderia cepacia. Physical and chemical variables were also monitored. Total bacterial abundance in water (based on DAPI staining) peaked during October 2000 and July 2001; while on leaves, total abundance peaked in January then declined through April with a second June peak. The peak in sediments was during October 2000 and numbers did not differ significantly between a pool and a riffle. Domain Bacteria numbers also exhibited significant temporal changes but the seasonal patterns differed from those based on DAPI staining. Abundance of B. cepacia varied temporally on leaves but not in water and sediments. Contrary to other studies, no significant correlations were seen between bacteriological and physical/chemical variables measured. However, spring run off seems to have been a factor in temporarily reduced numbers on leaves and sediments and increasing bacterioplankton numbers, likely due to allochthonous inputs. Based on prior studies, we expected the pattern of temporal change in bacterial numbers to vary among habitats. However, there were no differences between pool and riffle sediments and no significant correlations between bacteriological and abiotic variables. This may reflect the ability of bacteria to persist under varying temperature/nutrient conditions and flow regimes. The ability of B. cepacia to maintain fairly constant populations, in contrast to the overall assemblage, likely reflects the extreme versatility of this organism.","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":"74100117","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: 10.1127/0003-9136/2006/0166-0467
Verónica Ferreira, A. Elosegi, V. Gulis, J. Pozo, M. Graça
The replacement of diverse deciduous forests by eucalyptus plantations changes the timing, quality and quantity of litter inputs to streams, which has the potential to affect the activity of decomposers and thus ecosystem functioning. Here, we compared (a) the decomposition rate of alder and oak leaves incubated in deciduous and eucalyptus streams in Spain and Portugal, (b) the activity (fungal biomass and sporulation) and diversity (species richness and Pielou's evenness index) of the associated fungal communities and (c) changes in N and P content of leaves. Alder and oak leaves decomposed at similar rates in both stream types and countries, with the exception of oak leaves in the Spanish eucalyptus stream, which decomposed faster than in the corresponding deciduous stream or in the Portuguese eucalyptus stream. This difference was attributed to physical fragmentation due to flooding and not to forest cover. Higher nitrogen and phosphorus content and higher fungal biomass and sporulation were generally found on leaves from eucalyptus rather than from deciduous streams. The higher fungal activity in eucalyptus streams was attributed to higher water temperature and benthic organic matter storage. The Spanish eucalyptus stream had higher species richness of aquatic hyphomycetes than the deciduous one (27 vs. 20) while in Portugal the opposite was true (16 vs. 20). Fungal community evenness was significantly higher on alder leaves in eucalyptus than in deciduous streams. The community structure (MDS analysis) discriminated both stream types in Portugal much better than it did in Spain. At least for Portugal, differences between stream types can be explained by higher litter diversity in deciduous than in eucalyptus streams. In conclusion, stream fungal communities in Portugal were more affected by eucalyptus plantations than in Spain. In both countries, fungal diversity and activity were more affected by eucalyptus plantations than decomposition rates of submerged litter. We suggest therefore that, to mitigate the effect of eucalyptus plantations, deciduous trees could be planted on the river banks or, preferably, riparian strips of native vegetation should be left unmodified.
{"title":"Eucalyptus plantations affect fungal communities associated with leaf-litter decomposition in Iberian streams","authors":"Verónica Ferreira, A. Elosegi, V. Gulis, J. Pozo, M. Graça","doi":"10.1127/0003-9136/2006/0166-0467","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0467","url":null,"abstract":"The replacement of diverse deciduous forests by eucalyptus plantations changes the timing, quality and quantity of litter inputs to streams, which has the potential to affect the activity of decomposers and thus ecosystem functioning. Here, we compared (a) the decomposition rate of alder and oak leaves incubated in deciduous and eucalyptus streams in Spain and Portugal, (b) the activity (fungal biomass and sporulation) and diversity (species richness and Pielou's evenness index) of the associated fungal communities and (c) changes in N and P content of leaves. Alder and oak leaves decomposed at similar rates in both stream types and countries, with the exception of oak leaves in the Spanish eucalyptus stream, which decomposed faster than in the corresponding deciduous stream or in the Portuguese eucalyptus stream. This difference was attributed to physical fragmentation due to flooding and not to forest cover. Higher nitrogen and phosphorus content and higher fungal biomass and sporulation were generally found on leaves from eucalyptus rather than from deciduous streams. The higher fungal activity in eucalyptus streams was attributed to higher water temperature and benthic organic matter storage. The Spanish eucalyptus stream had higher species richness of aquatic hyphomycetes than the deciduous one (27 vs. 20) while in Portugal the opposite was true (16 vs. 20). Fungal community evenness was significantly higher on alder leaves in eucalyptus than in deciduous streams. The community structure (MDS analysis) discriminated both stream types in Portugal much better than it did in Spain. At least for Portugal, differences between stream types can be explained by higher litter diversity in deciduous than in eucalyptus streams. In conclusion, stream fungal communities in Portugal were more affected by eucalyptus plantations than in Spain. In both countries, fungal diversity and activity were more affected by eucalyptus plantations than decomposition rates of submerged litter. We suggest therefore that, to mitigate the effect of eucalyptus plantations, deciduous trees could be planted on the river banks or, preferably, riparian strips of native vegetation should be left unmodified.","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":"77635469","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: 10.1127/0003-9136/2006/0166-0535
M. Beklioğlu, G. Altinayar, C. Tan
The functioning of shallow lakes is supposedly very sensitive to water level fluctuations (WLF). Relationships between WLF and submerged macrophyte development were investigated in five Turkish shallow lakes located in a semi-arid to arid Mediterranean climate where the hydrological event of WLF is a common phenomenon. In all lakes, WLF emerged as a major factor determining submerged plant development. High submerged plant coverage was observed in four of the study lakes, Lake Beysehir, Lake Uluabat, Lake Marmara and Lake Mogan when the water level was low throughout the year or during growing season, submerged plants expanded; however, in Lake Isikli extensive submerged plant development was observed at high water levels during winter. In Lake Isikli, an increase of 25 % in the surface area was recorded, which, in turn, might have resulted in an increased potential for expansion of submerged plants. Furthermore, in all the lakes excluding Lake Beysehir, high submerged plant coverage coincided with a significant decrease in the amplitude of intra-annual water level fluctuations. The depth profile, expressed as the morphometry index (Z mean /Z max ), appeared to be critical for the development of extensive vegetation. Expansion of vegetation coincided with either an increased morphometry index or a flatter bottom profile. However, the impact of hydrology on lake morphometry differed between the lakes. In Lake Isikli, the high water level generated a slightly flatter, albeit not significantly so, bottom; however, in the remaining lakes the same effect was observed at low water level. Differences in the morphometry index in response to WLF appeared to depend on the original bottom profile, which is either conical or ellipsoid. Therefore, the impact of hydrology on the bottom profile of a lake may profoundly affect the extent of the littoral zone. Biomass of carp (Cyprinus carpio) had a strong inverse correlation with vegetation development in Lake Marmara and Lake Uluabat, therefore, carp might also have been important in macrophyte development. It may be concluded that littoral plant communities in shallow lakes located in semi-arid to arid regions appear to be particularly susceptible to water level fluctuations.
浅湖的功能被认为对水位波动(WLF)非常敏感。本文研究了位于半干旱至干旱地中海气候的五个土耳其浅湖的水淹与淹没植物发育之间的关系，其中水淹是一种常见的水文事件。在所有湖泊中，WLF都是决定水下植物发育的主要因素。Beysehir湖、Uluabat湖、Marmara湖和Mogan湖在全年或生长季节水位较低时，淹没植物数量增加;然而，在伊西克利湖，在冬季高水位时观察到广泛的水下植物发育。据记录，伊西克利湖的表面积增加了25%，这反过来又可能导致水下植物扩张的潜力增加。此外，在除Beysehir湖以外的所有湖泊中，淹没植物盖度高的同时，年内水位波动幅度也显著减小。以形态测量指数(Z mean /Z max)表示的深度剖面对粗放植被的发育至关重要。植被的扩张与形态测量指数的增加或底部轮廓的平坦相一致。然而，水文对湖泊形态的影响在湖泊之间存在差异。在伊西克利湖，高水位形成了一个略微平坦的湖底，尽管不是很明显;然而，在其余的湖泊中，在低水位也观察到同样的效果。对WLF响应的形态测量指数的差异似乎取决于原始的底部轮廓，即圆锥形或椭球形。因此，水文对湖底剖面的影响可能会深刻地影响沿岸带的范围。马尔马拉湖和乌鲁阿巴特湖的鲤鱼生物量与植被发育呈强烈的负相关，因此，鲤鱼可能在大型植物发育中也起着重要作用。由此可以得出结论，位于半干旱至干旱地区的浅湖沿岸植物群落似乎特别容易受到水位波动的影响。
{"title":"Water level control over submerged macrophyte development in five shallow lakes of Mediterranean Turkey","authors":"M. Beklioğlu, G. Altinayar, C. Tan","doi":"10.1127/0003-9136/2006/0166-0535","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0535","url":null,"abstract":"The functioning of shallow lakes is supposedly very sensitive to water level fluctuations (WLF). Relationships between WLF and submerged macrophyte development were investigated in five Turkish shallow lakes located in a semi-arid to arid Mediterranean climate where the hydrological event of WLF is a common phenomenon. In all lakes, WLF emerged as a major factor determining submerged plant development. High submerged plant coverage was observed in four of the study lakes, Lake Beysehir, Lake Uluabat, Lake Marmara and Lake Mogan when the water level was low throughout the year or during growing season, submerged plants expanded; however, in Lake Isikli extensive submerged plant development was observed at high water levels during winter. In Lake Isikli, an increase of 25 % in the surface area was recorded, which, in turn, might have resulted in an increased potential for expansion of submerged plants. Furthermore, in all the lakes excluding Lake Beysehir, high submerged plant coverage coincided with a significant decrease in the amplitude of intra-annual water level fluctuations. The depth profile, expressed as the morphometry index (Z mean /Z max ), appeared to be critical for the development of extensive vegetation. Expansion of vegetation coincided with either an increased morphometry index or a flatter bottom profile. However, the impact of hydrology on lake morphometry differed between the lakes. In Lake Isikli, the high water level generated a slightly flatter, albeit not significantly so, bottom; however, in the remaining lakes the same effect was observed at low water level. Differences in the morphometry index in response to WLF appeared to depend on the original bottom profile, which is either conical or ellipsoid. Therefore, the impact of hydrology on the bottom profile of a lake may profoundly affect the extent of the littoral zone. Biomass of carp (Cyprinus carpio) had a strong inverse correlation with vegetation development in Lake Marmara and Lake Uluabat, therefore, carp might also have been important in macrophyte development. It may be concluded that littoral plant communities in shallow lakes located in semi-arid to arid regions appear to be particularly susceptible to water level fluctuations.","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":"79568499","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: 10.1127/0003-9136/2006/0166-0557
R. Bachmann, M. Hoyer, D. Canfield, C. Schelske, F. J. Aldridge, H. Carrick, M. Coveney
We found the conclusion of SCHELSKE et al. (2003, Arch. Hydrobiol. 157:145-172) that Lake Apopka was not net heterotrophic was incorrect when annual rates of production and respiration for the entire lake ecosystem are taken into consideration. A new carbon budget for the water and sediments showed for the period of study the sum of the annual sources of organic carbon including primary production and inflows (765 g C m -2 yr -1 ) was less than the sum of the annual losses including respiration in the water and sediments and outflows (2497 g C m -2 yr -1 ). Diel oxygen curves demonstrated that it is possible to have oxygen supersaturation at the surface near midday and still have net heterotrophy over 24-h.
我们发现SCHELSKE et al. (2003, Arch。当考虑到整个湖泊生态系统的年生产速率和呼吸速率时，认为Apopka湖不是净异养的观点是不正确的。新的水和沉积物碳收支表明，在研究期间，包括初级生产和流入(765 g C m -2 yr -1)在内的年有机碳源的总和小于包括水和沉积物呼吸和流出(2497 g C m -2 yr -1)在内的年损失的总和。双氧曲线表明，在接近中午的时候，地表有可能出现氧过饱和，但在24小时内仍有净异养。
{"title":"Net production and net heterotrophy in Lake Apopka : a comment on SCHELSKE et al. (2003). Commentary and Authors' reply","authors":"R. Bachmann, M. Hoyer, D. Canfield, C. Schelske, F. J. Aldridge, H. Carrick, M. Coveney","doi":"10.1127/0003-9136/2006/0166-0557","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0557","url":null,"abstract":"We found the conclusion of SCHELSKE et al. (2003, Arch. Hydrobiol. 157:145-172) that Lake Apopka was not net heterotrophic was incorrect when annual rates of production and respiration for the entire lake ecosystem are taken into consideration. A new carbon budget for the water and sediments showed for the period of study the sum of the annual sources of organic carbon including primary production and inflows (765 g C m -2 yr -1 ) was less than the sum of the annual losses including respiration in the water and sediments and outflows (2497 g C m -2 yr -1 ). Diel oxygen curves demonstrated that it is possible to have oxygen supersaturation at the surface near midday and still have net heterotrophy over 24-h.","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":"72649482","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 : 2006-07-05DOI: 10.1127/0003-9136/2006/0166-0261
Miroslav Macek, C. Callieri, K. Šimek, A. Vázquez
Seasonal changes in the structure of ciliate assemblages in eleven oligotrophic mountain lakes at different altitudes, covering a wide pH range from 4.9 to 6.9, were studied. Seven mountain lakes lay above the timberline (0vre NeÅdalsvatn and Stavsvatn, Norway; Lochnagar, Scotland; Starolesnianske pleso and Nizne Terianske pleso, Slovak Republic; Chuna ozero, Russia; Lago Paione Superiore, Italy) and four acidified lakes (Cerne, Certovo, Plesne and Prasilske jezero, Sumava Mountains, Czech Republic) in the mountain forest. Additionally, thr tropical high latitude Lago de Alchichica (Mexico) was analysed. Ciliate taxons were identified using the quantitative protargol staining approach, and feeding patterns were tentatively detected by using fluorescence microscopy methods. Nano- to microphytoplankton hunters and/ or mixotrophic ciliates prevailed in all acidic lakes. Numbers of ciliates were very low (seasonal lake mean below 200 cells/I) except in two Tatra lakes (to 21000 cells/I). Prostomes of the genera Urotricha, Holophrya and Prorodon dominated in most of the samples, both numerically as well as in biomass (seasonal lake mean from 13.6 to 100% and 4.6 to 99.7%, respectively), particularly in acidified water lakes (Starolesnianske, Certovo and Prasilske jezero). Among mixotrophs, oligotrichs of genera Pelagostrombidium and Limnostrombidium were the most prominent (up to 49.9 and 64.6%, respectively). The picoplankton-feeders (minute oligotrichs, peritrichs and scuticociliates) were found to be an important component even in the oligotrophic environment but this ecological type never dominated within the water column (up to 22.2 and 30.3 %, respectively). Major food sources of gymnostomes, prevailing only in Lochnagar (82.5 and 87.5 %, respectively; Mesodinium sp.), remained unclear; large Askenasia spp. were apparently mixotrophic. Using a cluster analysis, the lakes were grouped according to the total numbers of ciliates and contributions of distinct ecological groups with different feeding patterns. Within low acidic lakes, Lochnagar differed from all others. The rest of the lakes was divided into two subgroups: remote pristine lakes of the Northern transect (the Norwegian lakes and Chuna ozero), and the others, geographically affiliated to the south transect (Pyreneans, Alps, Tatra Mts.). Such a differentiation is in good agreement with the clustering based on chemical parameters reported for the lakes. No marked differences in the ciliate distribution were detected when the above timberline- and forest surrounded mountain lakes were compared.
{"title":"Seasonal dynamics, composition and feeding patterns of ciliate assemblages in oligotrophic lakes covering a wide pH range","authors":"Miroslav Macek, C. Callieri, K. Šimek, A. Vázquez","doi":"10.1127/0003-9136/2006/0166-0261","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0261","url":null,"abstract":"Seasonal changes in the structure of ciliate assemblages in eleven oligotrophic mountain lakes at different altitudes, covering a wide pH range from 4.9 to 6.9, were studied. Seven mountain lakes lay above the timberline (0vre NeÅdalsvatn and Stavsvatn, Norway; Lochnagar, Scotland; Starolesnianske pleso and Nizne Terianske pleso, Slovak Republic; Chuna ozero, Russia; Lago Paione Superiore, Italy) and four acidified lakes (Cerne, Certovo, Plesne and Prasilske jezero, Sumava Mountains, Czech Republic) in the mountain forest. Additionally, thr tropical high latitude Lago de Alchichica (Mexico) was analysed. Ciliate taxons were identified using the quantitative protargol staining approach, and feeding patterns were tentatively detected by using fluorescence microscopy methods. Nano- to microphytoplankton hunters and/ or mixotrophic ciliates prevailed in all acidic lakes. Numbers of ciliates were very low (seasonal lake mean below 200 cells/I) except in two Tatra lakes (to 21000 cells/I). Prostomes of the genera Urotricha, Holophrya and Prorodon dominated in most of the samples, both numerically as well as in biomass (seasonal lake mean from 13.6 to 100% and 4.6 to 99.7%, respectively), particularly in acidified water lakes (Starolesnianske, Certovo and Prasilske jezero). Among mixotrophs, oligotrichs of genera Pelagostrombidium and Limnostrombidium were the most prominent (up to 49.9 and 64.6%, respectively). The picoplankton-feeders (minute oligotrichs, peritrichs and scuticociliates) were found to be an important component even in the oligotrophic environment but this ecological type never dominated within the water column (up to 22.2 and 30.3 %, respectively). Major food sources of gymnostomes, prevailing only in Lochnagar (82.5 and 87.5 %, respectively; Mesodinium sp.), remained unclear; large Askenasia spp. were apparently mixotrophic. Using a cluster analysis, the lakes were grouped according to the total numbers of ciliates and contributions of distinct ecological groups with different feeding patterns. Within low acidic lakes, Lochnagar differed from all others. The rest of the lakes was divided into two subgroups: remote pristine lakes of the Northern transect (the Norwegian lakes and Chuna ozero), and the others, geographically affiliated to the south transect (Pyreneans, Alps, Tatra Mts.). Such a differentiation is in good agreement with the clustering based on chemical parameters reported for the lakes. No marked differences in the ciliate distribution were detected when the above timberline- and forest surrounded mountain lakes were compared.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79750974","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 : 2006-07-01DOI: 10.1127/0003-9136/2006/0166-0343
J. Dahl, Richard K. Johnson
Weighted averaging (WA) regression and calibration methods are commonly used in paleoecology to infer environmental conditions in the past, but few stream studies have used these approaches on contemporary macroinvertebrate data sets. Here we examined if WA regression and calibration methods could better our understanding of the effects of acidification on Swedish stream ecosystems. Macroinvertebrate and water chemistry data from 232 stream sites in the northern and 154 stream sites in the southern parts of the country were used for model calibration. In addition, 42 randomly selected sites were used for model validation (25 in the north and 17 in the south). Inferred WA pH was compared to inferences of pH obtained using four commonly used acidity indices. Performance of the different methods was assessed using the r 2 -values and root mean square errors (RMSE) of regressions between inferred and observed pH. WA approaches were found to be slightly better than the four acidity indices studied here. However, both WA and the acidity indices performed poorly at the test sites in southern Sweden. This study shows that WA approaches could be useful for assessing acidity of Swedish streams, but the overall low r 2 -values indicate that factors other than pH also are affecting the macroinvertebrate assemblages confounding the pH-organism response relationship.
{"title":"Assessing the acidity of Swedish streams using benthic macroinvertebrates and weighted averaging (WA) regression and calibration","authors":"J. Dahl, Richard K. Johnson","doi":"10.1127/0003-9136/2006/0166-0343","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0343","url":null,"abstract":"Weighted averaging (WA) regression and calibration methods are commonly used in paleoecology to infer environmental conditions in the past, but few stream studies have used these approaches on contemporary macroinvertebrate data sets. Here we examined if WA regression and calibration methods could better our understanding of the effects of acidification on Swedish stream ecosystems. Macroinvertebrate and water chemistry data from 232 stream sites in the northern and 154 stream sites in the southern parts of the country were used for model calibration. In addition, 42 randomly selected sites were used for model validation (25 in the north and 17 in the south). Inferred WA pH was compared to inferences of pH obtained using four commonly used acidity indices. Performance of the different methods was assessed using the r 2 -values and root mean square errors (RMSE) of regressions between inferred and observed pH. WA approaches were found to be slightly better than the four acidity indices studied here. However, both WA and the acidity indices performed poorly at the test sites in southern Sweden. This study shows that WA approaches could be useful for assessing acidity of Swedish streams, but the overall low r 2 -values indicate that factors other than pH also are affecting the macroinvertebrate assemblages confounding the pH-organism response relationship.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81408513","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 : 2006-07-01DOI: 10.1127/0003-9136/2006/0166-0325
Paweł Koperski
Data on numbers and percentages of leech species sampled in 55 Polish freshwater environments were analysed. Most of these data were published between 1951-1998. The first aim of the present study was to recognize the most important ecological factors affecting the diversity and taxonomic composition of leech assemblages in Polish waters'. Evaluating the relative importance of these factors in explaining diversity and composition of the leech fauna was the second aim. The significance of six factors, potentially affecting the composition and diversity of the leech fauna was tested. These were: type of environment, size of environment, geographical location, presence of fish predation, sampling season and level of degradation. Two factors were found to be important determinants of the leech assemblage composition. The first were the specific properties of the ponds. Occurrence and percentages of certain leech species therein were significantly different from those in lakes. The second factor was the presence of fish or the intensity of fish predation. No significant differences in occurrence or percentages of species were found between geographic regions, habitat size and samples collected in various seasons. Lakes were the richest environments in terms of species number. The high mortality caused by sampling of leeches in small, semi-isolated ponds or in lakes localized in protected areas is discussed. Surprisingly, significantly lower species diversity was observed in environments with more intense fish predation.
{"title":"Relative importance of factors determining diversity and composition of freshwater leech assemblages (Hirudinea; Clitellata): a metaanalysis","authors":"Paweł Koperski","doi":"10.1127/0003-9136/2006/0166-0325","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0325","url":null,"abstract":"Data on numbers and percentages of leech species sampled in 55 Polish freshwater environments were analysed. Most of these data were published between 1951-1998. The first aim of the present study was to recognize the most important ecological factors affecting the diversity and taxonomic composition of leech assemblages in Polish waters'. Evaluating the relative importance of these factors in explaining diversity and composition of the leech fauna was the second aim. The significance of six factors, potentially affecting the composition and diversity of the leech fauna was tested. These were: type of environment, size of environment, geographical location, presence of fish predation, sampling season and level of degradation. Two factors were found to be important determinants of the leech assemblage composition. The first were the specific properties of the ponds. Occurrence and percentages of certain leech species therein were significantly different from those in lakes. The second factor was the presence of fish or the intensity of fish predation. No significant differences in occurrence or percentages of species were found between geographic regions, habitat size and samples collected in various seasons. Lakes were the richest environments in terms of species number. The high mortality caused by sampling of leeches in small, semi-isolated ponds or in lakes localized in protected areas is discussed. Surprisingly, significantly lower species diversity was observed in environments with more intense fish predation.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76262884","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 : 2006-07-01DOI: 10.1127/0003-9136/2006/0166-0363
J. Molinero, J. Pozo
We studied the leaf budget in two forest stream sites: site D was located in a stream that flows through deciduous forest, and site E was located in a stream that flows through a eucalyptus plantation. Leaf inputs, transport, benthic storage and breakdown rates at both sites at different periods were measured over 5 years. Data have been combined to calculate leaf budgets with the assumption that both streams were in steady state. The total leaf input was 20 % lower at site E, but the mean benthic stock of leaves and the amount of leaves that was processed were about 1.5 times higher than at site D. Inputs of nitrogen and phosphorus associated with leaves were 50 and 20 % lower at site E, but small differences in the benthic storage of nutrients were observed between the two sites. The streams processed 31-57% of the nitrogen, and 20-57% of the phosphorus contained in the leaf input. Afforestation with eucalyptus has a low impact on leaf litter processing as the longer residence time of eucalyptus leaves in the stream balances their lower processing rate. However, it modifies nutrient fluxes associated with leaf litter due to the low nutrient content of eucalyptus leaves and to their role as nutrient sources during leaf decay. At both streams, alder litter was processed more efficiently than other species and was the main source of nitrogen and phosphorus for stream decomposers. We hypothesize that dependence on this fast decaying species is an indication of the disturbance of CPOM dynamics due to historical changes in our streams and that it may be difficult to isolate the effects of former forest disturbances from the impact of eucalyptus plantations.
{"title":"Organic matter, nitrogen and phosphorus fluxes associated with leaf litter in two small streams with different riparian vegetation: a budget approach","authors":"J. Molinero, J. Pozo","doi":"10.1127/0003-9136/2006/0166-0363","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0166-0363","url":null,"abstract":"We studied the leaf budget in two forest stream sites: site D was located in a stream that flows through deciduous forest, and site E was located in a stream that flows through a eucalyptus plantation. Leaf inputs, transport, benthic storage and breakdown rates at both sites at different periods were measured over 5 years. Data have been combined to calculate leaf budgets with the assumption that both streams were in steady state. The total leaf input was 20 % lower at site E, but the mean benthic stock of leaves and the amount of leaves that was processed were about 1.5 times higher than at site D. Inputs of nitrogen and phosphorus associated with leaves were 50 and 20 % lower at site E, but small differences in the benthic storage of nutrients were observed between the two sites. The streams processed 31-57% of the nitrogen, and 20-57% of the phosphorus contained in the leaf input. Afforestation with eucalyptus has a low impact on leaf litter processing as the longer residence time of eucalyptus leaves in the stream balances their lower processing rate. However, it modifies nutrient fluxes associated with leaf litter due to the low nutrient content of eucalyptus leaves and to their role as nutrient sources during leaf decay. At both streams, alder litter was processed more efficiently than other species and was the main source of nitrogen and phosphorus for stream decomposers. We hypothesize that dependence on this fast decaying species is an indication of the disturbance of CPOM dynamics due to historical changes in our streams and that it may be difficult to isolate the effects of former forest disturbances from the impact of eucalyptus plantations.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85714086","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}
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