Thomas Hübener - Academia.edu (original) (raw)
Papers by Thomas Hübener
Taxonomy
Stephanodiscus makarovae, a taxon originally described from Russia, is morphologically similar to... more Stephanodiscus makarovae, a taxon originally described from Russia, is morphologically similar to several other taxa within Cyclostephanos, namely C. invisitatus, C. delicatus and C. tholiformis. However, it has not yet been transferred into Cyclostephanos, perhaps due to the difficulty in identifying it, as its original description is available only in the Russian language. To investigate its morphology, a detailed morphological comparison of S. makarovae and C. invisitatus was done from 286 SEM micrographs of 12 monoclonal strains. We performed a three-gene phylogenetic analysis with strains from eight additional taxa to independently confirm the position of S. makarovae. The morphology of S. makarovae shows key features of the genus Cyclostephanos and this attribution is supported by the phylogeny. Here we propose the transfer of the taxon S. makarovae to Cyclostephanos, considering the morphological and molecular data. According to both the molecular and morphological data, C. d...
Mit 113,5 km2 Wasserfläche und einem Einzugsgebiet von 1230 km2 ist die Müritz (62 m HN) der zwei... more Mit 113,5 km2 Wasserfläche und einem Einzugsgebiet von 1230 km2 ist die Müritz (62 m HN) der zweitgrösste See des nordmitteleuropäischen Tieflandes (Knapp et al. 1999). Sie war in den vergangenen Jahrzehnten bereits mehrfach das Ziel paläohydrologischer und landschaftsgenetischer Untersuchungen, die sich bislang jedoch auf das terrestrische und telmatische Umfeld beschränkten. Durch Kaiser (1998) und Kaiser et al. (2002) wurde der bisherige Wissensstand detailliert zusammengefasst. Die hier vorgestellten Seebohrungen hatten das Ziel, die Landschafts- und Gewässerentwicklung anhand von Seesedimenten gut aufgelöst zu rekonstruieren und offene Fragen zu Wasserstandsschwankungen zu klären. Die Untersuchung der Seesedimente bot zudem die Chance einer über ein grosses Einzugsgebiet integrierenden Rekonstruktion der Vegetationsgeschichte sowie der erstmaligen Bearbeitung der Sedimentations- und Trophieentwicklung der Müritz seit dem Spätglazial.researc
SIL 2018: The International Society of Limnology, Aug 1, 2018
Diatom Research, Jul 14, 2022
Perspectives in Phycology, 2018
Algae-especially highly diverse groups with huge shares of stenoecious species-are versatile indi... more Algae-especially highly diverse groups with huge shares of stenoecious species-are versatile indicators for different parameters of water quality. Containing determinable, persisting structures further qualifies some algae groups to be used in paleolimnological analyses. The most commonly used algae group in paleolimnology are diatoms-a multitude of diatom training sets exists for various variables of water quality, notably pH, total phosphorous and salinity. This mini-review discusses advances in and demands on such training sets. Furthermore, a brief outline of past paleolimnological research is giving. Recent research trends are discussed, e.g. analyzing complex interactions of several variables-especially a possible climatic effect on pH or trophy-and the application of new molecular methods (NGS, metabarcoding) for bioindication.
Perspectives in Phycology, 2018
Plant Diversity and Evolution, 2011
... Gordon & Pacheco (2007) and Peroutka et al. ... The microalgae spectra of U. foliosa and ... more ... Gordon & Pacheco (2007) and Peroutka et al. ... The microalgae spectra of U. foliosa and U. gibba from Ivory Coast differed con-siderably and only 6 taxa (out of 45 and 31 taxa recorded in traps of U. foliosa and U. gibba, respectively) were in common (5 Charophyceae, 1 ...
Flora - Morphology, Distribution, Functional Ecology of Plants, 2009
Abstract. Soluble and particulate phosphorus forms in the surface water of the eutrophic shallow ... more Abstract. Soluble and particulate phosphorus forms in the surface water of the eutrophic shallow Lake Bützow were investigated from March to November 1998. Solu-ble reactive phosphorus (SRP) and dissolved organic phosphorus (DOP) of the filtered water were analysed. Suspended particulate matter (SPM) was characterized by particulate organic matter (POM), particulate organic carbon (POC), particulate phosphorus (PP), particulate iron (PFe), phytoplankton biomass (PB) and Chl a. PP was investigated in more detail by means of sequential chemical extraction (Psenner et al., 1984) and the analysis of polyphosphates and phospholipids. In spring, the lowest SRP values and highest PP values were recorded. Over the course of the year, SRP
Changes in composition of diatom (Bacillariophyceae) communities and pollen content were analyzed... more Changes in composition of diatom (Bacillariophyceae) communities and pollen content were analyzed in two cores from the lake Krakower See, Mecklenburg-Vorpommern, Northern Germany. Based on the pollen stratigraphy, a time-depth-curve was built that allowed an estimate of the rate of sedimentation. The pollen curves, especially those of settlement indicators, showed the human influence in the surrounding area. Diatom assemblages clearly indicated that human activities had influenced not only the terrestrial vegetation but also the water body of the lake and it’s trophic conditions. From a natural oligo- to mesotrophic lake that had small oscillations in prehistoric times it switched rela-tively fast into an eutrophic one around 700 years ago. This radical change in the trophic status was an effect of both damming up for mills in the 13th century and increasing settlement activities around the lake. Key words: paleolimnology, diatom and pollen stratigraphy, TP reconstruction
Quaternary Science Reviews
Journal of Marine Science and Engineering
Benthic diatom communities dominate sheltered shallow inner coastal waters of the atidal Southern... more Benthic diatom communities dominate sheltered shallow inner coastal waters of the atidal Southern Baltic Sea. However, their photosynthetic oxygen production and respiratory oxygen consumption is rarely evaluated. In the Baltic Sea carbon budget benthic diatom communities are often not included, since phytoplankton is regarded as the main primary producer. Therefore, two wind-protected stations (2–49-cm depths) were investigated between July 2010 and April 2012 using undisturbed sediment cores in combination with planar oxygen optodes. We expected strong fluctuations in the biological activity parameters in the incubated cores over the course of the seasons. The sediment particles at both stations were dominated by fine sand with a median grain size of 131–138 µm exhibiting an angular shape with many edges, which were less mobile compared to exposed coastal sites of the Southern Baltic Sea. These sand grains inhabited dense communities of rather small epipsammic diatoms (<10 µm)....
Environmental Microbiology
Diatoms are among the few eukaryotes known to store nitrate (NO3 - ) and to use it as an electron... more Diatoms are among the few eukaryotes known to store nitrate (NO3 - ) and to use it as an electron acceptor for respiration in the absence of light and O2 . Using microscopy and 15 N stable isotope incubations, we studied the relationship between dissimilatory nitrate/nitrite reduction to ammonium (DNRA) and diel vertical migration of diatoms in phototrophic microbial mats and the underlying sediment of a sinkhole in Lake Huron (USA). We found that the diatoms rapidly accumulated NO3 - at the mat-water interface in the afternoon and 40% of the population migrated deep into the sediment, where they were exposed to dark and anoxic conditions for ~75 % of the day. The vertical distribution of DNRA rates and diatom abundance maxima coincided, suggesting that DNRA was the main energy generating metabolism of the diatom population. We conclude that the illuminated redox-dynamic ecosystem selects for migratory diatoms that can store nitrate for respiration in the absence of light. A major implication of this study is that the dominance of DNRA over denitrification is not explained by kinetics or thermodynamics. Rather, the dynamic conditions select for migratory diatoms that perform DNRA and can outcompete sessile denitrifiers. This article is protected by copyright. All rights reserved.
Taxonomy
Stephanodiscus makarovae, a taxon originally described from Russia, is morphologically similar to... more Stephanodiscus makarovae, a taxon originally described from Russia, is morphologically similar to several other taxa within Cyclostephanos, namely C. invisitatus, C. delicatus and C. tholiformis. However, it has not yet been transferred into Cyclostephanos, perhaps due to the difficulty in identifying it, as its original description is available only in the Russian language. To investigate its morphology, a detailed morphological comparison of S. makarovae and C. invisitatus was done from 286 SEM micrographs of 12 monoclonal strains. We performed a three-gene phylogenetic analysis with strains from eight additional taxa to independently confirm the position of S. makarovae. The morphology of S. makarovae shows key features of the genus Cyclostephanos and this attribution is supported by the phylogeny. Here we propose the transfer of the taxon S. makarovae to Cyclostephanos, considering the morphological and molecular data. According to both the molecular and morphological data, C. d...
Mit 113,5 km2 Wasserfläche und einem Einzugsgebiet von 1230 km2 ist die Müritz (62 m HN) der zwei... more Mit 113,5 km2 Wasserfläche und einem Einzugsgebiet von 1230 km2 ist die Müritz (62 m HN) der zweitgrösste See des nordmitteleuropäischen Tieflandes (Knapp et al. 1999). Sie war in den vergangenen Jahrzehnten bereits mehrfach das Ziel paläohydrologischer und landschaftsgenetischer Untersuchungen, die sich bislang jedoch auf das terrestrische und telmatische Umfeld beschränkten. Durch Kaiser (1998) und Kaiser et al. (2002) wurde der bisherige Wissensstand detailliert zusammengefasst. Die hier vorgestellten Seebohrungen hatten das Ziel, die Landschafts- und Gewässerentwicklung anhand von Seesedimenten gut aufgelöst zu rekonstruieren und offene Fragen zu Wasserstandsschwankungen zu klären. Die Untersuchung der Seesedimente bot zudem die Chance einer über ein grosses Einzugsgebiet integrierenden Rekonstruktion der Vegetationsgeschichte sowie der erstmaligen Bearbeitung der Sedimentations- und Trophieentwicklung der Müritz seit dem Spätglazial.researc
SIL 2018: The International Society of Limnology, Aug 1, 2018
Diatom Research, Jul 14, 2022
Perspectives in Phycology, 2018
Algae-especially highly diverse groups with huge shares of stenoecious species-are versatile indi... more Algae-especially highly diverse groups with huge shares of stenoecious species-are versatile indicators for different parameters of water quality. Containing determinable, persisting structures further qualifies some algae groups to be used in paleolimnological analyses. The most commonly used algae group in paleolimnology are diatoms-a multitude of diatom training sets exists for various variables of water quality, notably pH, total phosphorous and salinity. This mini-review discusses advances in and demands on such training sets. Furthermore, a brief outline of past paleolimnological research is giving. Recent research trends are discussed, e.g. analyzing complex interactions of several variables-especially a possible climatic effect on pH or trophy-and the application of new molecular methods (NGS, metabarcoding) for bioindication.
Perspectives in Phycology, 2018
Plant Diversity and Evolution, 2011
... Gordon & Pacheco (2007) and Peroutka et al. ... The microalgae spectra of U. foliosa and ... more ... Gordon & Pacheco (2007) and Peroutka et al. ... The microalgae spectra of U. foliosa and U. gibba from Ivory Coast differed con-siderably and only 6 taxa (out of 45 and 31 taxa recorded in traps of U. foliosa and U. gibba, respectively) were in common (5 Charophyceae, 1 ...
Flora - Morphology, Distribution, Functional Ecology of Plants, 2009
Abstract. Soluble and particulate phosphorus forms in the surface water of the eutrophic shallow ... more Abstract. Soluble and particulate phosphorus forms in the surface water of the eutrophic shallow Lake Bützow were investigated from March to November 1998. Solu-ble reactive phosphorus (SRP) and dissolved organic phosphorus (DOP) of the filtered water were analysed. Suspended particulate matter (SPM) was characterized by particulate organic matter (POM), particulate organic carbon (POC), particulate phosphorus (PP), particulate iron (PFe), phytoplankton biomass (PB) and Chl a. PP was investigated in more detail by means of sequential chemical extraction (Psenner et al., 1984) and the analysis of polyphosphates and phospholipids. In spring, the lowest SRP values and highest PP values were recorded. Over the course of the year, SRP
Changes in composition of diatom (Bacillariophyceae) communities and pollen content were analyzed... more Changes in composition of diatom (Bacillariophyceae) communities and pollen content were analyzed in two cores from the lake Krakower See, Mecklenburg-Vorpommern, Northern Germany. Based on the pollen stratigraphy, a time-depth-curve was built that allowed an estimate of the rate of sedimentation. The pollen curves, especially those of settlement indicators, showed the human influence in the surrounding area. Diatom assemblages clearly indicated that human activities had influenced not only the terrestrial vegetation but also the water body of the lake and it’s trophic conditions. From a natural oligo- to mesotrophic lake that had small oscillations in prehistoric times it switched rela-tively fast into an eutrophic one around 700 years ago. This radical change in the trophic status was an effect of both damming up for mills in the 13th century and increasing settlement activities around the lake. Key words: paleolimnology, diatom and pollen stratigraphy, TP reconstruction
Quaternary Science Reviews
Journal of Marine Science and Engineering
Benthic diatom communities dominate sheltered shallow inner coastal waters of the atidal Southern... more Benthic diatom communities dominate sheltered shallow inner coastal waters of the atidal Southern Baltic Sea. However, their photosynthetic oxygen production and respiratory oxygen consumption is rarely evaluated. In the Baltic Sea carbon budget benthic diatom communities are often not included, since phytoplankton is regarded as the main primary producer. Therefore, two wind-protected stations (2–49-cm depths) were investigated between July 2010 and April 2012 using undisturbed sediment cores in combination with planar oxygen optodes. We expected strong fluctuations in the biological activity parameters in the incubated cores over the course of the seasons. The sediment particles at both stations were dominated by fine sand with a median grain size of 131–138 µm exhibiting an angular shape with many edges, which were less mobile compared to exposed coastal sites of the Southern Baltic Sea. These sand grains inhabited dense communities of rather small epipsammic diatoms (<10 µm)....
Environmental Microbiology
Diatoms are among the few eukaryotes known to store nitrate (NO3 - ) and to use it as an electron... more Diatoms are among the few eukaryotes known to store nitrate (NO3 - ) and to use it as an electron acceptor for respiration in the absence of light and O2 . Using microscopy and 15 N stable isotope incubations, we studied the relationship between dissimilatory nitrate/nitrite reduction to ammonium (DNRA) and diel vertical migration of diatoms in phototrophic microbial mats and the underlying sediment of a sinkhole in Lake Huron (USA). We found that the diatoms rapidly accumulated NO3 - at the mat-water interface in the afternoon and 40% of the population migrated deep into the sediment, where they were exposed to dark and anoxic conditions for ~75 % of the day. The vertical distribution of DNRA rates and diatom abundance maxima coincided, suggesting that DNRA was the main energy generating metabolism of the diatom population. We conclude that the illuminated redox-dynamic ecosystem selects for migratory diatoms that can store nitrate for respiration in the absence of light. A major implication of this study is that the dominance of DNRA over denitrification is not explained by kinetics or thermodynamics. Rather, the dynamic conditions select for migratory diatoms that perform DNRA and can outcompete sessile denitrifiers. This article is protected by copyright. All rights reserved.