Pub Date : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/279
J. Elso, L. Greenberg
Habitat use, movements and survival of individual 0+ brown trout (Salmo trutta) during winter
0+褐鳟(Salmo trutta)个体在冬季的栖息地利用、运动和生存
{"title":"Habitat use, movements and survival of individual 0+ brown trout (Salmo trutta) during winter","authors":"J. Elso, L. Greenberg","doi":"10.1127/archiv-hydrobiol/152/2001/279","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/279","url":null,"abstract":"Habitat use, movements and survival of individual 0+ brown trout (Salmo trutta) during winter","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"194 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133584782","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/237
M. Barrat-Segretain
The colonisation of two invasive species, Elodea canadensis and Elodea nuttallii was studied in the cut-off channels of the Rhone floodplain (France). The characteristics of the stations where the two species occurred are reported. The two species colonise new areas most often through vegetative fragments transported by water currents and the connectivity of cut-off channels to the main river is probably the essential parameter of their colonisation by the two Elodea species. The replacement of E. canadensis by E. nuttallii was compared in two cut-off channels, one subject only to the natural dynamics of the main river (flood disturbances), and the second subject to restoration work. In the first case the replacement was low and the two species were still found in the channel but did not co-exist in the same area. In the second case the replacement was very rapid (less than one year) and resulted in the total exclusion of E. canadensis. Several hypotheses are given (interspecific competition or other factors) to explain the replacement process, and more studies are needed to elucidate the mechanism of this phenomenon.
{"title":"Invasive species in the Rhône River floodplain (France): replacement of Elodea canadensis Michaux by E. nuttallii St. John in two former river channels","authors":"M. Barrat-Segretain","doi":"10.1127/archiv-hydrobiol/152/2001/237","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/237","url":null,"abstract":"The colonisation of two invasive species, Elodea canadensis and Elodea nuttallii was studied in the cut-off channels of the Rhone floodplain (France). The characteristics of the stations where the two species occurred are reported. The two species colonise new areas most often through vegetative fragments transported by water currents and the connectivity of cut-off channels to the main river is probably the essential parameter of their colonisation by the two Elodea species. The replacement of E. canadensis by E. nuttallii was compared in two cut-off channels, one subject only to the natural dynamics of the main river (flood disturbances), and the second subject to restoration work. In the first case the replacement was low and the two species were still found in the channel but did not co-exist in the same area. In the second case the replacement was very rapid (less than one year) and resulted in the total exclusion of E. canadensis. Several hypotheses are given (interspecific competition or other factors) to explain the replacement process, and more studies are needed to elucidate the mechanism of this phenomenon.","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125216538","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/339
F. Gherardi, Patrizia Acquistapace, G. Santini
In analysing the eco-ethological traits of animal populations from the viewpoint of conservation biology, an understanding of the foraging activity of endangered species provides useful clues on habitat requirements and resource utilisation. The present study examined the foraging excursions of 60 specimens of the threatened crayfish, Austropotamobius pallipes, in a stream of central Italy. Foraging activity was related to both the distance travelled and the area covered, as well as to the organic content of the substrates investigated. Results were discussed under the premises of SCHOENER'S (1971) theory of feeding strategies. The white-clawed crayfish minimised the time spent feeding: foraging excursions did not exceed one hour and the range of food search increased with time. Energy and nutrient intake were however maximised: crayfish fed on the substrates having higher organic carbon and nitrogen contents. Inter-sexual food partitioning was shown, males and females mostly feeding on vegetable debris and mosses, respectively. We speculate that this is a mechanism to avoid competition between dominant males and subordinate females.
{"title":"Forag ing by a threatened species - the whiteclawed crayfish, Austropotamobius pallipes","authors":"F. Gherardi, Patrizia Acquistapace, G. Santini","doi":"10.1127/archiv-hydrobiol/152/2001/339","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/339","url":null,"abstract":"In analysing the eco-ethological traits of animal populations from the viewpoint of conservation biology, an understanding of the foraging activity of endangered species provides useful clues on habitat requirements and resource utilisation. The present study examined the foraging excursions of 60 specimens of the threatened crayfish, Austropotamobius pallipes, in a stream of central Italy. Foraging activity was related to both the distance travelled and the area covered, as well as to the organic content of the substrates investigated. Results were discussed under the premises of SCHOENER'S (1971) theory of feeding strategies. The white-clawed crayfish minimised the time spent feeding: foraging excursions did not exceed one hour and the range of food search increased with time. Energy and nutrient intake were however maximised: crayfish fed on the substrates having higher organic carbon and nitrogen contents. Inter-sexual food partitioning was shown, males and females mostly feeding on vegetable debris and mosses, respectively. We speculate that this is a mechanism to avoid competition between dominant males and subordinate females.","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129813463","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/215
I. Combroux, G. Bornette, N. Willby, C. Amoros
{"title":"Regenerative strategies of aquatic plants in disturbed habitats: the role of the propagule bank","authors":"I. Combroux, G. Bornette, N. Willby, C. Amoros","doi":"10.1127/archiv-hydrobiol/152/2001/215","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/215","url":null,"abstract":"","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114923746","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/297
A. Wright, L. A. Smock
Macroinvertebrate community composition, abundance and production were measured in a sand-bottomed, headwater stream on the Coastal Plain physiographic province in the southeastern U.S.A. The stream's watershed had experienced almost no anthropogenic disturbance for over 100 years and thus the stream represented as close to pristine, reference conditions as occurs in this geographic region. Macroinvertebrates were sampled over one year in the three dominant habitats in the stream: sand sediment, submerged wood and macrophytes (Sparganium americanum). Total taxa richness as well as the taxa richness of Ephemeroptera, Plecoptera, Trichoptera and Chironomidae all were greater than in streams flowing through more disturbed watersheds in the area. Annual mean habitat-specific density and biomass were highest in the sediment; density was lowest on the wood and biomass lowest on Sparganium. Habitat-specific production was 39-42 g m -2 y -1 in the sediment and on wood and 16 g m -2 y -1 on Sparganium. The majority of production in all three habitats was by Chironomidae, which comprised 80-92% of total production in each habitat. Taxa in the collector-gatherer and predator functional feeding groups accounted for the majority of production in the sediment and on wood, whereas filter-feeders were predominant on Sparganium. Whole-stream production, calculated by summing habitat-specific values that had been weighted for habitat availability, was 64 g m -2 y -1 , considerably higher than production in more disturbed streams in the region. About 65 % of the total production occurred in the sediment, 26 % on wood, and 9 % on Sparganium. The tanypod chironomid Conchapelopia had the highest production of any taxon in the stream at 19 g m -2 y -1 . The production to biomass ratio for the macroinvertebrate community was 33.3; ratios for six taxa of chironomids exceeded 100. Along with the higher species richness in this stream, production of macroinvertebrates was at least twice as high as that in nearby streams with more disturbed watersheds. These differences may be attributable to the long time since the last anthropogenic disturbance of the stream's watershed, which has led to a mature forest covering nearly all of the watershed and which has resulted in a more stable stream flow and less disturbance of the sediment during high flow than in streams in more disturbed watersheds.
在美国东南部沿海平原地理省的一条沙底源溪流中测量了大型无脊椎动物群落的组成、丰度和产量。该溪流的流域在100多年中几乎没有经历过人为干扰，因此该溪流代表了该地理区域最接近原始参考条件的河流。在一年多的时间里，在河流的三个主要栖息地:沙质沉积物、淹没木材和大型植物(美洲Sparganium americum)中取样了大型无脊椎动物。总分类丰富度以及蜉蝣目、翼翅目、毛翅目和手蛾科的分类丰富度均高于受干扰程度较高的流域。年平均生境比密度和生物量在沉积物中最高;密度最低的是木材，生物量最低的是米草。不同生境的产量在沉积物和木材上为39 ~ 42 g m -2 y -1，在米草上为16 g m -2 y -1。3个生境的产量均以摇尾蝇科为主，占各生境产量的80-92%。在沉积物和木材中，收集-采集和捕食功能摄食类群的产量占大多数，而在米草属植物上以滤食性为主。通过对栖息地可用性加权的生境特定值求和计算得出的全河流产量为64克/立方米/立方米，大大高于该地区受干扰程度较高的河流的产量。总产量的65%发生在沉积物中，26%发生在木材上，9%发生在谷草上。在所有分类单元中，翼足类(tanypod chironomid Conchapelopia)产量最高，为19 g m -2 y -1。大型无脊椎动物群落的产量与生物量之比为33.3;摇尾虫有6个分类群的比值超过100。随着物种丰富度的提高，这条河流的大型无脊椎动物产量至少是附近流域受干扰更大的河流的两倍。这些差异可能是由于自上次对河流流域的人为干扰以来的很长时间，这使得成熟的森林覆盖了几乎所有的流域，这使得河流流量更稳定，在高流量时泥沙的干扰比受干扰更大的流域的河流更少。
{"title":"Macroinvertebrate community structure and production in a low-gradient stream in an undisturbed watershed","authors":"A. Wright, L. A. Smock","doi":"10.1127/archiv-hydrobiol/152/2001/297","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/297","url":null,"abstract":"Macroinvertebrate community composition, abundance and production were measured in a sand-bottomed, headwater stream on the Coastal Plain physiographic province in the southeastern U.S.A. The stream's watershed had experienced almost no anthropogenic disturbance for over 100 years and thus the stream represented as close to pristine, reference conditions as occurs in this geographic region. Macroinvertebrates were sampled over one year in the three dominant habitats in the stream: sand sediment, submerged wood and macrophytes (Sparganium americanum). Total taxa richness as well as the taxa richness of Ephemeroptera, Plecoptera, Trichoptera and Chironomidae all were greater than in streams flowing through more disturbed watersheds in the area. Annual mean habitat-specific density and biomass were highest in the sediment; density was lowest on the wood and biomass lowest on Sparganium. Habitat-specific production was 39-42 g m -2 y -1 in the sediment and on wood and 16 g m -2 y -1 on Sparganium. The majority of production in all three habitats was by Chironomidae, which comprised 80-92% of total production in each habitat. Taxa in the collector-gatherer and predator functional feeding groups accounted for the majority of production in the sediment and on wood, whereas filter-feeders were predominant on Sparganium. Whole-stream production, calculated by summing habitat-specific values that had been weighted for habitat availability, was 64 g m -2 y -1 , considerably higher than production in more disturbed streams in the region. About 65 % of the total production occurred in the sediment, 26 % on wood, and 9 % on Sparganium. The tanypod chironomid Conchapelopia had the highest production of any taxon in the stream at 19 g m -2 y -1 . The production to biomass ratio for the macroinvertebrate community was 33.3; ratios for six taxa of chironomids exceeded 100. Along with the higher species richness in this stream, production of macroinvertebrates was at least twice as high as that in nearby streams with more disturbed watersheds. These differences may be attributable to the long time since the last anthropogenic disturbance of the stream's watershed, which has led to a mature forest covering nearly all of the watershed and which has resulted in a more stable stream flow and less disturbance of the sediment during high flow than in streams in more disturbed watersheds.","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115508186","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/315
G. Mills, J. McArthur, C. Wolfe, J. Aho, R. Rader
Fatty acid and hydrocarbon composition were determined in decomposing leaf packets of sweetgum (Liquidambar styraciflua) and water oak (Quercus nigra) from a snag habitat in a southeastern blackwater stream. The initial total fatty acid and hydrocarbon concentrations in sweetgum leaves were significantly greater than in the oak species. Higher concentrations of unsaturated fatty acids and dicyclic diterpenoid hydrocarbons accounted for most of this difference. Both of these biochemical subgroups are preferentially degraded relative to the bulk leaf material and other compounds within their respective lipid classes. No significant differences remained after 70 days of decomposition. Cuticular fatty acids are selectively preserved and thus, increased relative to noncuticular components during decomposition. The bacterially derived iso- and anteiso-branched-chain fatty acids increased markedly after 23 days. The results of this study suggest that qualitative differences in lipid composition may contribute to the observed difference in overall decomposition rate of leaves between these species.
{"title":"Changes in fatty acid and hydrocarbon composition of leaves during decomposition in a southeastern blackwater stream","authors":"G. Mills, J. McArthur, C. Wolfe, J. Aho, R. Rader","doi":"10.1127/archiv-hydrobiol/152/2001/315","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/315","url":null,"abstract":"Fatty acid and hydrocarbon composition were determined in decomposing leaf packets of sweetgum (Liquidambar styraciflua) and water oak (Quercus nigra) from a snag habitat in a southeastern blackwater stream. The initial total fatty acid and hydrocarbon concentrations in sweetgum leaves were significantly greater than in the oak species. Higher concentrations of unsaturated fatty acids and dicyclic diterpenoid hydrocarbons accounted for most of this difference. Both of these biochemical subgroups are preferentially degraded relative to the bulk leaf material and other compounds within their respective lipid classes. No significant differences remained after 70 days of decomposition. Cuticular fatty acids are selectively preserved and thus, increased relative to noncuticular components during decomposition. The bacterially derived iso- and anteiso-branched-chain fatty acids increased markedly after 23 days. The results of this study suggest that qualitative differences in lipid composition may contribute to the observed difference in overall decomposition rate of leaves between these species.","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115586211","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/253
E. Núñez-Olivera, M. García-Álvaro, N. Beaucourt, J. Martínez-Abaigar
The concentrations of seven elements (N, P, K, Ca, Mg, Fe and Na) were measured every two weeks during an annual cycle, in four species of submerged aquatic bryophytes: two mosses (Fontinalis antipyretica and F. squamosa), a foliose liverwort (Jungermannia exsertifolia subsp. cordifolia) and a thalloid liverwort (Pellia endiviifolia). The hypothesis under consideration was whether their elemental composition over the year showed a seasonal pattern and, if so, whether those changes depended on internal or environmental factors. The elements showing most frequently an annual cycle were N, P, Na and Fe, and the most common temporal trend was that with the lowest concentrations appearing in spring and the highest ones in autumn. Our data suggest that the seasonal cycles depended on the interaction of both internal and environmental factors: 1) the annual cycle of vegetative growth in aquatic bryophytes, which causes a concomitant cycle of dilution/concentration of elements within the plant tissues; 2) the annual changes in sclerophylly in some species, such as J. cordifolia; and 3) the temporal variation in the physical and chemical features of the stream of origin. However, only scattered correlations were found between the concentrations of a given element in the bryophytes and the concentration of that element in the surrounding water. Thus, bryophytes do not behave as mere absorbers of elements, but more complex systems, when the temporal variation in their element composition is considered.
{"title":"Changes in element concentrations in aquatic bryophytes over an annual cycle","authors":"E. Núñez-Olivera, M. García-Álvaro, N. Beaucourt, J. Martínez-Abaigar","doi":"10.1127/archiv-hydrobiol/152/2001/253","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/253","url":null,"abstract":"The concentrations of seven elements (N, P, K, Ca, Mg, Fe and Na) were measured every two weeks during an annual cycle, in four species of submerged aquatic bryophytes: two mosses (Fontinalis antipyretica and F. squamosa), a foliose liverwort (Jungermannia exsertifolia subsp. cordifolia) and a thalloid liverwort (Pellia endiviifolia). The hypothesis under consideration was whether their elemental composition over the year showed a seasonal pattern and, if so, whether those changes depended on internal or environmental factors. The elements showing most frequently an annual cycle were N, P, Na and Fe, and the most common temporal trend was that with the lowest concentrations appearing in spring and the highest ones in autumn. Our data suggest that the seasonal cycles depended on the interaction of both internal and environmental factors: 1) the annual cycle of vegetative growth in aquatic bryophytes, which causes a concomitant cycle of dilution/concentration of elements within the plant tissues; 2) the annual changes in sclerophylly in some species, such as J. cordifolia; and 3) the temporal variation in the physical and chemical features of the stream of origin. However, only scattered correlations were found between the concentrations of a given element in the bryophytes and the concentration of that element in the surrounding water. Thus, bryophytes do not behave as mere absorbers of elements, but more complex systems, when the temporal variation in their element composition is considered.","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133712438","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/329
J. Boenigk, H. Arndt, E. Cleven
Video microscopy was applied to observe the feeding by Spumella on fluorescently labeled bacteria (FLB) as well as on unstained bacteria. Ingestion rates were similar for unstained bacteria and for FLB. However, FLB were egested after a vacuole passage time of about three minutes while the vacuole passage time of unstained bacteria exceeded twenty minutes. Significant differences were found between the cumulative number of subsequent observed ingestions of FLB and food vacuole content. The assumption of a similar treatment of FLB and unstained living bacteria is therefore incorrect for Spumella. Thus, ingestion rates calculated from the number of FLB in food vacuoles underestimate real ingestion of this species.
{"title":"The problematic nature of fluorescently labeled bacteria (FLB) in Spumella feeding experiments an explanation by using video microscopy","authors":"J. Boenigk, H. Arndt, E. Cleven","doi":"10.1127/archiv-hydrobiol/152/2001/329","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/329","url":null,"abstract":"Video microscopy was applied to observe the feeding by Spumella on fluorescently labeled bacteria (FLB) as well as on unstained bacteria. Ingestion rates were similar for unstained bacteria and for FLB. However, FLB were egested after a vacuole passage time of about three minutes while the vacuole passage time of unstained bacteria exceeded twenty minutes. Significant differences were found between the cumulative number of subsequent observed ingestions of FLB and food vacuole content. The assumption of a similar treatment of FLB and unstained living bacteria is therefore incorrect for Spumella. Thus, ingestion rates calculated from the number of FLB in food vacuoles underestimate real ingestion of this species.","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116372731","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/177
K. Havens, J. Beaver, T. East, A. J. Rodusky, B. Sharfstein, A. Amand, A. Steinman
An in situ mesocosm experiment was conducted to evaluate the effects of increased nutrient loading on both producers and micro-consumers (protozoa, rotifers, and micro-crustacea) in the nutrient-deficient littoral zone of a subtropical lake. Areas of the natural community were enclosed in replicate 1.2 m 2 transparent tubes and treated with nitrogen, phosphorus, or nitrogen plus phosphorus over 28 days. Responses of six distinct community components (floating surface periphyton mats, phytoplankton, epiphyton associated with Utricularia, epiphyton on live and dead stems of Eleocharis, and a benthic algal mat) were evaluated and compared to non-enriched controls. All treatments were carried out in triplicate and nutrient inputs simulated those measured in the lake's more eutrophic pelagic region. Nutrient additions stimulated growth in a consistent manner across both habitats and trophic levels. Although there was a limited number of responses to addition of nitrogen or phosphorus alone, the overwhelming response was increased biomass when the two nutrients were added together. One community component that did not display an increase in algal biomass in response to nutrient addition was the benthic algal mat. Nevertheless, benthic consumers increased significantly in all nutrient-addition treatments. This may have been a response to the rain of particulate material stimulated by nutrients higher up in the water column. To our knowledge, this is the first study to evaluate nutrient effects on littoral micro-consumers in a subtropical setting; results generally were consistent with those obtained in temperate lakes.
{"title":"Nutrient effects on producers and consumers in the littoral plankton and periphyton of a subtropical lake","authors":"K. Havens, J. Beaver, T. East, A. J. Rodusky, B. Sharfstein, A. Amand, A. Steinman","doi":"10.1127/archiv-hydrobiol/152/2001/177","DOIUrl":"https://doi.org/10.1127/archiv-hydrobiol/152/2001/177","url":null,"abstract":"An in situ mesocosm experiment was conducted to evaluate the effects of increased nutrient loading on both producers and micro-consumers (protozoa, rotifers, and micro-crustacea) in the nutrient-deficient littoral zone of a subtropical lake. Areas of the natural community were enclosed in replicate 1.2 m 2 transparent tubes and treated with nitrogen, phosphorus, or nitrogen plus phosphorus over 28 days. Responses of six distinct community components (floating surface periphyton mats, phytoplankton, epiphyton associated with Utricularia, epiphyton on live and dead stems of Eleocharis, and a benthic algal mat) were evaluated and compared to non-enriched controls. All treatments were carried out in triplicate and nutrient inputs simulated those measured in the lake's more eutrophic pelagic region. Nutrient additions stimulated growth in a consistent manner across both habitats and trophic levels. Although there was a limited number of responses to addition of nitrogen or phosphorus alone, the overwhelming response was increased biomass when the two nutrients were added together. One community component that did not display an increase in algal biomass in response to nutrient addition was the benthic algal mat. Nevertheless, benthic consumers increased significantly in all nutrient-addition treatments. This may have been a response to the rain of particulate material stimulated by nutrients higher up in the water column. To our knowledge, this is the first study to evaluate nutrient effects on littoral micro-consumers in a subtropical setting; results generally were consistent with those obtained in temperate lakes.","PeriodicalId":146956,"journal":{"name":"Archiv für Hydrobiologie","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122322799","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 : 2001-08-12DOI: 10.1127/archiv-hydrobiol/152/2001/203
Arianne Y. Albert, C. Borkent, S. Duquette, M. Voordouw, B. Anholt
The distribution of the supratidal copepod Tigriopus californicus overlaps widely with that of larvae of the introduced mosquito Aedes togoi. Overlap in resource use suggests the possibility of negative interactions between the two species. To test this possibility, we manipulated the abundance of mosquito larvae in the field and found that increasing the number of larvae reduced the number of copepodites present 28 days later. A laboratory grazing experiment demonstrated that individual A. togoi (instars 2-3) clear about 25 times more water of algae than similarly sized T. californi cus. Laboratory experiments also demonstrated that A. togoi can be a very efficient predator of copepod nauplii. The selection imposed by age-specific predation on cope pods may have some life-history consequences.
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