S. Jawak, Shubhang Kumar, A. J. Luis, P. Pandit, S. F. Wankhede
Glaciers play a crucial role in the study of the climate change pattern of the Earth. Remote sensing with access to large archives of data has the ability to monitor glaciers frequently throughout the year. Therefore, remote sensing is the most beneficial tool for the study of glacier dynamics. Fed by many tributaries from different sides, the Amery Ice Shelf (AIS) is one of the largest ice shelves that drains ice from the Antarctic ice sheet into the Southern Ocean. This study focuses on the eastern and the western tributaries of the AIS. The primary objective of the study was to derive the velocity of the tributary glaciers and the secondary objective was to compare variations in their velocities between the summer and winter season. This study was carried on using the European Space Agency’s (ESA) Sentinel-1 satellite’s Synthetic Aperture Radar (SAR) data acquired from the Sentinel data portal. Offset tracking method was applied to the Ground Range Detected (GRD) product of the Sentinel-1 interferometric wide (IW) swath acquisition mode. The maximum velocity in summer was observed to be around 610 m/yr in the eastern tributary glacier meeting the ice shelf near the Pickering Nunatak, and around 345 m/yr in the Charybdis Glacier Basin from the western side. The maximum velocity in the winter was observed to be 553 m/yr in the eastern side near the Pickering Nunatak whereas 323 m/yr from the western side in the Charybdis Glacier Basin. The accuracy of the derived glacier velocities was computed using bias and root mean square (RMS) error. For the analysis, the publicly available velocity datasets were used. The accuracy based on RMS error was observed to be 85-90% for both seasons with bias values up to 25 m/yr and root mean square error values up to 30 m/yr.
冰川在地球气候变化模式的研究中起着至关重要的作用。利用大量数据档案的遥感能够全年频繁地监测冰川。因此，遥感是研究冰川动力学最有利的工具。Amery冰架(AIS)是最大的冰架之一，由来自不同侧面的许多支流组成，它将南极冰盖的冰排入南大洋。本研究以东西部支流为研究对象。这项研究的主要目的是得出支流冰川的速度，次要目的是比较它们在夏季和冬季之间的速度变化。这项研究是利用欧洲空间局(ESA) Sentinel-1卫星从Sentinel数据门户获取的合成孔径雷达(SAR)数据进行的。将偏移跟踪方法应用于Sentinel-1干涉宽(IW)条纹采集模式的Ground Range Detected (GRD) product。夏季最大流速在皮克林努纳塔克冰架附近的东部支流冰川约为610 m/yr，在Charybdis冰川盆地约为345 m/yr。冬季观测到的最大速度在皮克林努纳塔克附近的东侧为553 m/yr，而在Charybdis冰川盆地的西侧为323 m/yr。利用偏差和均方根误差计算所得冰川速度的精度。为了进行分析，使用了公开可用的速度数据集。两个季节基于均方根误差的精度为85-90%，偏差值高达25米/年，均方根误差值高达30米/年。
{"title":"Seasonal glacier surface velocity fluctuation and contribution of the Eastern and Western Tributary Glaciers in Amery Ice Shelf, East Antarctica","authors":"S. Jawak, Shubhang Kumar, A. J. Luis, P. Pandit, S. F. Wankhede","doi":"10.5817/cpr2019-1-5","DOIUrl":"https://doi.org/10.5817/cpr2019-1-5","url":null,"abstract":"Glaciers play a crucial role in the study of the climate change pattern of the Earth. Remote sensing with access to large archives of data has the ability to monitor glaciers frequently throughout the year. Therefore, remote sensing is the most beneficial tool for the study of glacier dynamics. Fed by many tributaries from different sides, the Amery Ice Shelf (AIS) is one of the largest ice shelves that drains ice from the Antarctic ice sheet into the Southern Ocean. This study focuses on the eastern and the western tributaries of the AIS. The primary objective of the study was to derive the velocity of the tributary glaciers and the secondary objective was to compare variations in their velocities between the summer and winter season. This study was carried on using the European Space Agency’s (ESA) Sentinel-1 satellite’s Synthetic Aperture Radar (SAR) data acquired from the Sentinel data portal. Offset tracking method was applied to the Ground Range Detected (GRD) product of the Sentinel-1 interferometric wide (IW) swath acquisition mode. The maximum velocity in summer was observed to be around 610 m/yr in the eastern tributary glacier meeting the ice shelf near the Pickering Nunatak, and around 345 m/yr in the Charybdis Glacier Basin from the western side. The maximum velocity in the winter was observed to be 553 m/yr in the eastern side near the Pickering Nunatak whereas 323 m/yr from the western side in the Charybdis Glacier Basin. The accuracy of the derived glacier velocities was computed using bias and root mean square (RMS) error. For the analysis, the publicly available velocity datasets were used. The accuracy based on RMS error was observed to be 85-90% for both seasons with bias values up to 25 m/yr and root mean square error values up to 30 m/yr.","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71342129","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}
F. Hrbáček, D. Nývlt, K. Láska, M. Knazková, Barbora Kampová, Zbyněk Engel, M. Oliva, C. Mueller
This study summarizes the current state of the active layer and permafrost research on James Ross Island. The analysis of climate parameters covers the reference period 2011–2017. The mean annual air temperature at the AWS-JGM site was -6.9°C (ranged from -3.9°C to -8.2°C). The mean annual ground temperature at the depth of 5 cm was -5.5°C (ranged from -3.3°C to -6.7°C) and it also reached -5.6°C (ranged from -4.0 to -6.8°C) at the depth of 50 cm. The mean daily ground temperature at the depth of 5 cm correlated moderately up to strongly with the air temperature depending on the season of the year. Analysis of the snow effect on the ground thermal regime confirmed a low insulating effect of snow cover when snow thickness reached up to 50 cm. A thicker snow accumulation, reaching at least 70 cm, can develop around the hyaloclastite breccia boulders where a well pronounced insulation effect on the near-surface ground thermal regime was observed. The effect of lithology on the ground physical properties and the active layer thickness was also investigated. Laboratory analysis of ground thermal properties showed variation in thermal conductivity (0.3 to 0.9 W m-1 K-1). The thickest active layer (89 cm) was observed on the Berry Hill slopes site, where the lowest thawing degree days index (321 to 382°C·day) and the highest value of thermal conductivity (0.9 W m-1 K-1) was observed. The clearest influence of lithological conditions on active layer thickness was observed on the CALM-S grid. The site comprises a sandy Holocene marine terrace and muddy sand of the Whisky Bay Formation. Surveying using a manual probe, ground penetrating radar, and an electromagnetic conductivity meter clearly showed the effect of the lithological boundary on local variability of the active layer thickness.
本文综述了詹姆士罗斯岛活土层和永久冻土层的研究现状。气候参数分析覆盖参考期2011-2017年。AWS-JGM站点年平均气温为-6.9°C(范围从-3.9°C到-8.2°C)。5 cm深度年平均地温为-5.5℃(-3.3℃~ -6.7℃)，50 cm深度年平均地温为-5.6℃(-4.0℃~ -6.8℃)。5 cm深度日平均地温与气温随季节的变化呈中至强相关。积雪对地面热状态的影响分析证实，当积雪厚度达到50 cm时，积雪的隔热作用较低。在透明晶砾岩角砾岩周围可形成较厚的积雪，厚度至少可达70 cm，在那里观察到对近地表地表热状态的明显隔热作用。研究了岩性对地层物性和活动层厚度的影响。对地面热特性的实验室分析显示，导热系数(0.3至0.9 W m-1 K-1)发生了变化。贝里丘坡地活性层厚度最大(89 cm)，融化日数指数最低(321 ~ 382℃·d)，热导率最高(0.9 W m-1 K-1)。在CALM-S网格上，岩性条件对活动层厚度的影响最为明显。场地包括全新世的沙质海洋阶地和威士忌湾地层的泥沙。利用人工探头、探地雷达和电磁电导率仪进行的测量清楚地显示了岩性边界对活动层厚度局部变化的影响。
{"title":"Permafrost and active layer research on James Ross Island: An overview","authors":"F. Hrbáček, D. Nývlt, K. Láska, M. Knazková, Barbora Kampová, Zbyněk Engel, M. Oliva, C. Mueller","doi":"10.5817/cpr2019-1-3","DOIUrl":"https://doi.org/10.5817/cpr2019-1-3","url":null,"abstract":"This study summarizes the current state of the active layer and permafrost research on James Ross Island. The analysis of climate parameters covers the reference period 2011–2017. The mean annual air temperature at the AWS-JGM site was -6.9°C (ranged from -3.9°C to -8.2°C). The mean annual ground temperature at the depth of 5 cm was -5.5°C (ranged from -3.3°C to -6.7°C) and it also reached -5.6°C (ranged from -4.0 to -6.8°C) at the depth of 50 cm. The mean daily ground temperature at the depth of 5 cm correlated moderately up to strongly with the air temperature depending on the season of the year. Analysis of the snow effect on the ground thermal regime confirmed a low insulating effect of snow cover when snow thickness reached up to 50 cm. A thicker snow accumulation, reaching at least 70 cm, can develop around the hyaloclastite breccia boulders where a well pronounced insulation effect on the near-surface ground thermal regime was observed. The effect of lithology on the ground physical properties and the active layer thickness was also investigated. Laboratory analysis of ground thermal properties showed variation in thermal conductivity (0.3 to 0.9 W m-1 K-1). The thickest active layer (89 cm) was observed on the Berry Hill slopes site, where the lowest thawing degree days index (321 to 382°C·day) and the highest value of thermal conductivity (0.9 W m-1 K-1) was observed. The clearest influence of lithological conditions on active layer thickness was observed on the CALM-S grid. The site comprises a sandy Holocene marine terrace and muddy sand of the Whisky Bay Formation. Surveying using a manual probe, ground penetrating radar, and an electromagnetic conductivity meter clearly showed the effect of the lithological boundary on local variability of the active layer thickness.","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45475103","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}
Long-term manipulated warming experiments using the open top chamber (OTC) approach tend to mimick the future climate and predict the changes in photosynthesis and production of vegetation under globally changed climate. In Antarctica, several long-term experiments are carried out recently. Here we report to the lichens grown in OTCs installed at the Fildes Peninsula (King George Island). The field study compares primary photochemical processes of photosynthesis in Antarctic lichen Placopsis antarctica grown for one year in OTC and compared to outside plot (control). We measured effective quantum yield of photosystem II (ΦPSII) of green algae part of thallus in 10 min. interval for 12 days. We examined the responses of diurnal ΦPSII to PAR in relation to environmental factors through continuous 12-d-long monitoring of chlorophyll fluorescence parameters ΦPSII in particular. Daily courses of ΦPSII and photosynthetic electron transport rate (ETR) to photosynthetically active radiation (PAR) and hydration state of thallus have been assumed to reflect changes in physiological status of P. antarctica in changing Antarctic environment. The data indicate that OTC microenvironment may lead to partial limitation of photosynthetic processes in P. antarctica during austral summer season. The limitation is caused by accelerated dehydration of thallus in OTC compared to the outside generally colder control plot, and thus shortened physiologically active period of lichens in OTC.
{"title":"Open top chamber microclimate may limit photosynthetic processes in Antarctic lichen: Case study from King George Island, Antarctica","authors":"A. Casanova-Katny, M. Barták, C. Gutiérrez","doi":"10.5817/cpr2019-1-6","DOIUrl":"https://doi.org/10.5817/cpr2019-1-6","url":null,"abstract":"Long-term manipulated warming experiments using the open top chamber (OTC) approach tend to mimick the future climate and predict the changes in photosynthesis and production of vegetation under globally changed climate. In Antarctica, several long-term experiments are carried out recently. Here we report to the lichens grown in OTCs installed at the Fildes Peninsula (King George Island). The field study compares primary photochemical processes of photosynthesis in Antarctic lichen Placopsis antarctica grown for one year in OTC and compared to outside plot (control). We measured effective quantum yield of photosystem II (ΦPSII) of green algae part of thallus in 10 min. interval for 12 days. We examined the responses of diurnal ΦPSII to PAR in relation to environmental factors through continuous 12-d-long monitoring of chlorophyll fluorescence parameters ΦPSII in particular. Daily courses of ΦPSII and photosynthetic electron transport rate (ETR) to photosynthetically active radiation (PAR) and hydration state of thallus have been assumed to reflect changes in physiological status of P. antarctica in changing Antarctic environment. The data indicate that OTC microenvironment may lead to partial limitation of photosynthetic processes in P. antarctica during austral summer season. The limitation is caused by accelerated dehydration of thallus in OTC compared to the outside generally colder control plot, and thus shortened physiologically active period of lichens in OTC.","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71342140","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}
Open top chambers (OTCs) were established in the northern part of the James Ross Island, Antarctic Peninsula, as a part of long-term program in January 2007. They were installed in two typical locations differing in vegetation cover. First group was set in a seashore ecosystem dominated by moss carpet supplemented with few lichen species. The other group was located on the top of a volcanic mesa (350 m a.s.l.) with irregular cover of lichens Usnea antarctica and Umbilicaria decussata. Temperature regimes inside and outside OTCs were continuously measured and related to year-round reference meteorological data. For majority of OTC installations, temperature increase caused by OTC was apparent in the period of September-March. Detailed analysis of chamber effect on the increase in air, surface, vegetation, and ground temperatures was done for late austral summer seasons of 2007 and 2008, and 10 years later, the seasons of 2017 and 2018. The OTC-induced temperature increase was more pronounced for mesa than seashore plot. For both locations, OTC-induced increase in temperature was highest for warm days with full sunshine and limited wind speed. On stormy days with overcast sky and high wind speed, the shift in temperature was smaller. Consequences of a long-term manipulation of Antarctic terrestrial ecosystems by OTCs for moss and lichen ecophysiology are discussed.
{"title":"Microclimate variability of Antarctic terrestrial ecosystems manipulated by open top chambers: Comparison of selected austral summer seasons within a decade","authors":"M. Barták, K. Láska, J. Hájek, P. Váczi","doi":"10.5817/cpr2019-1-8","DOIUrl":"https://doi.org/10.5817/cpr2019-1-8","url":null,"abstract":"Open top chambers (OTCs) were established in the northern part of the James Ross Island, Antarctic Peninsula, as a part of long-term program in January 2007. They were installed in two typical locations differing in vegetation cover. First group was set in a seashore ecosystem dominated by moss carpet supplemented with few lichen species. The other group was located on the top of a volcanic mesa (350 m a.s.l.) with irregular cover of lichens Usnea antarctica and Umbilicaria decussata. Temperature regimes inside and outside OTCs were continuously measured and related to year-round reference meteorological data. For majority of OTC installations, temperature increase caused by OTC was apparent in the period of September-March. Detailed analysis of chamber effect on the increase in air, surface, vegetation, and ground temperatures was done for late austral summer seasons of 2007 and 2008, and 10 years later, the seasons of 2017 and 2018. The OTC-induced temperature increase was more pronounced for mesa than seashore plot. For both locations, OTC-induced increase in temperature was highest for warm days with full sunshine and limited wind speed. On stormy days with overcast sky and high wind speed, the shift in temperature was smaller. Consequences of a long-term manipulation of Antarctic terrestrial ecosystems by OTCs for moss and lichen ecophysiology are discussed.","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71342316","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}
The aim of this study was to investigate the fungal community associated with fruits and vegetables transported into the Antarctic region and observe qualitative changes of their surface mycobiota after UV-C treatment. This measure is used to prevent the post-harvest diseases of stored fruits and vegetables and reduce the risk of introducing non-native species to the Antarctic environment. In total, 82 strains of filamentous fungi were isolated from the surfaces of 64 pieces of fresh fruits and vegetables before and after their UV-C treatment. They were assigned to the genera Penicillium, Fusarium, Mucor, Cladosporium, and Acremonium. After the UV-C treatment of the examined fruits and vegetables, spores of the genera Fusarium, Cladosporium and Acremonium were not detected, while spores of the genera Penicillium and Mucor were more resistant and stayed viable after the treatment. Penicillium strains prevailed in the examined samples. Their introduction to the Antarctic environment could represent a potential risk for endemic autochthonous organisms.
{"title":"Fungal species associated with fruit and vegetables transported to the J.G. Mendel station and the influence of UV-C treatment on their fungal community","authors":"M. Laichmanová, I. Sedláček","doi":"10.5817/cpr2019-1-7","DOIUrl":"https://doi.org/10.5817/cpr2019-1-7","url":null,"abstract":"The aim of this study was to investigate the fungal community associated with fruits and vegetables transported into the Antarctic region and observe qualitative changes of their surface mycobiota after UV-C treatment. This measure is used to prevent the post-harvest diseases of stored fruits and vegetables and reduce the risk of introducing non-native species to the Antarctic environment. In total, 82 strains of filamentous fungi were isolated from the surfaces of 64 pieces of fresh fruits and vegetables before and after their UV-C treatment. They were assigned to the genera Penicillium, Fusarium, Mucor, Cladosporium, and Acremonium. After the UV-C treatment of the examined fruits and vegetables, spores of the genera Fusarium, Cladosporium and Acremonium were not detected, while spores of the genera Penicillium and Mucor were more resistant and stayed viable after the treatment. Penicillium strains prevailed in the examined samples. Their introduction to the Antarctic environment could represent a potential risk for endemic autochthonous organisms.","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71342307","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}
The aim of this study was to examine the effect of extreme climatic conditions and a long stay in isolation on levels of three haematological parameters in the polar expedition participants. This article describes changes in erythrocyte count, hemoglobin and transferrin levels measured on the 9th Czech Antarctic Scientific Expedition during the period of the Antarctic summer. A total of 15 sera samples were collected shortly before the expedition, the second sampling was performed halfway through the stay and the third at the very end of the expedition stationed at the Czech Research Station of J. G. Mendel. The erythrocyte count and the levels of transferrin were significantly increased in between all three sample collections (with p-value < 0.01). A statistically significant increase in hemoglobin levels was only detected between the first and the final sampling (p
{"title":"Changes in haematological parameters during a summer expedition in Antarctica","authors":"A. Žákovská, Olivie Zezulová","doi":"10.5817/cpr2019-1-9","DOIUrl":"https://doi.org/10.5817/cpr2019-1-9","url":null,"abstract":"The aim of this study was to examine the effect of extreme climatic conditions and a long stay in isolation on levels of three haematological parameters in the polar expedition participants. This article describes changes in erythrocyte count, hemoglobin and transferrin levels measured on the 9th Czech Antarctic Scientific Expedition during the period of the Antarctic summer. A total of 15 sera samples were collected shortly before the expedition, the second sampling was performed halfway through the stay and the third at the very end of the expedition stationed at the Czech Research Station of J. G. Mendel. The erythrocyte count and the levels of transferrin were significantly increased in between all three sample collections (with p-value < 0.01). A statistically significant increase in hemoglobin levels was only detected between the first and the final sampling (p","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42555357","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}
In the project aiming to determine the lichen mycota of James Ross Island, we identified a new lichenicolous fungus species which is reported from Antarctica for the first time: Sphaerellothecium reticulatum on Flavoparmelia gerlachei. Although this species was identified on other parmelioid lichens, it was never reported on Flavoparmelia spp.
{"title":"Sphaerellothecium reticulatum (Zopf) Etayo, a new lichenicolous fungusfor Antarctica","authors":"M. Halıcı, M. Barták","doi":"10.5817/CPR2019-1-2","DOIUrl":"https://doi.org/10.5817/CPR2019-1-2","url":null,"abstract":"In the project aiming to determine the lichen mycota of James Ross Island, we identified a new lichenicolous fungus species which is reported from Antarctica for the first time: Sphaerellothecium reticulatum on Flavoparmelia gerlachei. Although this species was identified on other parmelioid lichens, it was never reported on Flavoparmelia spp.","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49353705","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}
In this study, we investigated the effects of shock freezing on physiological properties and consequent growth of in the Antarctic alga Stigeoclonium sp. and comparative coccal alga Diplosphaera chodatii on agar plates. Culture of algae grown in liquid medium were used to study subzero temperatures on the species resistance to shock freezing. Then, microalgae were frozen in liquid nitrogen and inoculated on BBM agar after thawing. Physiological status of algae was evaluated by chlorophyll fluorescence parameters during 28 days. The results showed that interspecific differences existed in their tolerance to shock freezing, as well as their consequent growth rate on agars. Direct effects of freezing in liquid nitrogen was demonstrated in chlorophyll fluorescence parameters recorded immediately after thawing the samples (in liquid medium). In spite of the fact that majority of cells was destroyed by shock freezing, the potential of photochemical processes in PS II (FV/FM) remained constant in D. chodatii. It may indicate high resistance of the species to freezing/thawing cycles and a capability of the surviving cells, core chlorophylls in PS II respectively, to perform photosynthetic processes related to PS II. Contrastingly, Stigeoclonium sp. showed a shock freezing-dependent decrease in FV/FM. When shock-frozen, thawed and inoculated on agar plates, the culture of D. chodatii, and Stigeoclonium sp. showed cultivation time-dependent increase in chlorophyll fluorescence parameters (FV/FM, FS).
{"title":"The effect of shock freezing on physiological properties and consequent growth of Antarctic filamentous (Stigeoclonium sp.) and coccal alga (Diplosphaera chodatii) on agar plates","authors":"A. Orekhova, M. Barták, Aleyna Özkar, J. Elster","doi":"10.5817/cpr2019-1-4","DOIUrl":"https://doi.org/10.5817/cpr2019-1-4","url":null,"abstract":"In this study, we investigated the effects of shock freezing on physiological properties and consequent growth of in the Antarctic alga Stigeoclonium sp. and comparative coccal alga Diplosphaera chodatii on agar plates. Culture of algae grown in liquid medium were used to study subzero temperatures on the species resistance to shock freezing. Then, microalgae were frozen in liquid nitrogen and inoculated on BBM agar after thawing. Physiological status of algae was evaluated by chlorophyll fluorescence parameters during 28 days. The results showed that interspecific differences existed in their tolerance to shock freezing, as well as their consequent growth rate on agars. Direct effects of freezing in liquid nitrogen was demonstrated in chlorophyll fluorescence parameters recorded immediately after thawing the samples (in liquid medium). In spite of the fact that majority of cells was destroyed by shock freezing, the potential of photochemical processes in PS II (FV/FM) remained constant in D. chodatii. It may indicate high resistance of the species to freezing/thawing cycles and a capability of the surviving cells, core chlorophylls in PS II respectively, to perform photosynthetic processes related to PS II. Contrastingly, Stigeoclonium sp. showed a shock freezing-dependent decrease in FV/FM. When shock-frozen, thawed and inoculated on agar plates, the culture of D. chodatii, and Stigeoclonium sp. showed cultivation time-dependent increase in chlorophyll fluorescence parameters (FV/FM, FS).","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71342122","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}
Dehydration-induced decrease in photosynthetic activity was investigated in five poikilohydric autotrophs using chlorophyll fluorescence parameters recorded during controlled desiccation. For the study, two representatives of mosses from alpine zone (Rhizomnium punctatum, Rhytidiadelphus squarrosus) of the Jeseníky Mts. (Czech Republic) were used. Other two experimental species were mediterranean habitats liverwort (Pellia endiviifolia) and moss (Palustriella commutata), collected from under Woodwardia radicans canopy in the Nature Reserve Valle delle Ferriere (Italy). The last species was a liverwort (Marchantia polymorpha) collected from lowland site (Brno, Moravia, Czech Republic). We investigated the relationship between relative water content (RWC) and several chlorophyll fluorescence parameters evaluating primary photochemical processes of photosynthesis, such as effective quantum yield of photosynthetic processes in photosystem II (ΦPSII), and non-photochemical quenching (qN). With desiccation from fully wet (RWC = 100%) to dry state (RWC = 0%), ΦPSII exhibited a rapid (R. punctatum) and slow decline of ΦPSII (R. squarrosus, P. endiviifolia, M. polymorpha, and P. commutata). Shapes of dehydration-response curves were species-specific. RWC0.5, i.e. the RWC at which the sample showed half of maximum ΦPSII, reflected the species-specificity. It reached 65% in desiccation sensitive (R. punctatum), 53% and 43% in semi-tolerant (P. commutata and R. squarrosus), 24% and 18% in desiccation-tolerant species (P. endiviifolia and M. polymorpha). In all experimental species, non-photochemical quenching (qN) of absorbed light energy showed high values at RWC = 100% and a slight increase with desiccation. Steady state chlorophyll fluorescence (FS) remained high during desiccation and was not correlated with ΦPSII.
利用控制干燥过程中记录的叶绿素荧光参数，研究了五种淡水自养生物因脱水而导致的光合活性下降。在这项研究中，使用了来自Jeseníky Mts（捷克共和国）高山地带的两种代表性苔藓（Rhytidiadelphus squarosus）。另外两个实验物种是地中海栖息地的苔草（Pellia endivifolia）和苔藓（Palustriella commuta），它们是从自然保护区Valle delle Ferriere（意大利）的Woodardia radicans树冠下采集的。最后一个物种是从低地（布尔诺，摩拉维亚，捷克共和国）采集的苔草（Marchantia polymorpha）。我们研究了相对含水量（RWC）与评价光合作用初级光化学过程的几个叶绿素荧光参数之间的关系，如光系统II中光合过程的有效量子产量（ΦPSII）和非光化学猝灭（qN）。随着从完全湿润（RWC=100%）到干燥状态（RWC=0%）的干燥，ΦPSII表现出快速（R.punctatum）和缓慢下降（R.squarosus、P.endivifolia、M.polymorpha和P.commuta）。脱水反应曲线的形状是物种特异性的。RWC0.5，即样本显示最大ΦPSII一半的RWC，反映了物种特异性。在干燥敏感种（R.punctatum）中达到65%，在半耐种（P.commuta和R.squarosus）中分别达到53%和43%，在耐干燥种（P.endivifolia和M.polymorpha）中达到24%和18%。在所有实验物种中，在RWC=100%时，吸收光能的非光化学猝灭（qN）显示出较高的值，并且随着干燥而略有增加。稳态叶绿素荧光（FS）在干燥过程中保持较高水平，与ΦPSII无关。
{"title":"Comparative research of photosynthetic processes in selected poikilohydric organisms from Mediterranean and Central-European alpine habitats","authors":"G. Giudici, J. Hájek, M. Barták, S. Kubešová","doi":"10.5817/cpr2018-2-24","DOIUrl":"https://doi.org/10.5817/cpr2018-2-24","url":null,"abstract":"Dehydration-induced decrease in photosynthetic activity was investigated in five poikilohydric autotrophs using chlorophyll fluorescence parameters recorded during controlled desiccation. For the study, two representatives of mosses from alpine zone (Rhizomnium punctatum, Rhytidiadelphus squarrosus) of the Jeseníky Mts. (Czech Republic) were used. Other two experimental species were mediterranean habitats liverwort (Pellia endiviifolia) and moss (Palustriella commutata), collected from under Woodwardia radicans canopy in the Nature Reserve Valle delle Ferriere (Italy). The last species was a liverwort (Marchantia polymorpha) collected from lowland site (Brno, Moravia, Czech Republic). We investigated the relationship between relative water content (RWC) and several chlorophyll fluorescence parameters evaluating primary photochemical processes of photosynthesis, such as effective quantum yield of photosynthetic processes in photosystem II (ΦPSII), and non-photochemical quenching (qN). With desiccation from fully wet (RWC = 100%) to dry state (RWC = 0%), ΦPSII exhibited a rapid (R. punctatum) and slow decline of ΦPSII (R. squarrosus, P. endiviifolia, M. polymorpha, and P. commutata). Shapes of dehydration-response curves were species-specific. RWC0.5, i.e. the RWC at which the sample showed half of maximum ΦPSII, reflected the species-specificity. It reached 65% in desiccation sensitive (R. punctatum), 53% and 43% in semi-tolerant (P. commutata and R. squarrosus), 24% and 18% in desiccation-tolerant species (P. endiviifolia and M. polymorpha). In all experimental species, non-photochemical quenching (qN) of absorbed light energy showed high values at RWC = 100% and a slight increase with desiccation. Steady state chlorophyll fluorescence (FS) remained high during desiccation and was not correlated with ΦPSII. ","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48416283","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}
Since 2000, the entire Antarctic diatom flora is being revised using a more fine-grained taxonomy based on a better analysis and interpretation of the morphological and molecular observations. Despite the increased diatom research and efforts, the diversity and ecology of diatoms of lichen inhabiting flora of James Ross Island weren’t studied yet. To reveal the actual diatom diversity, samples were collected during February and March 2018 from lichens on the Ulu Peninsula, James Ross Island, a 2,450 km2 large island, situated in the north-western part of the Weddell Sea, close to the northern tip of the Antarctic Peninsula. The analysis of 29 lichen samples revealed the presence of 56 diatom taxa belonging to 17 genera. The most abundant species were Luticola muticopsis, Hantzschia amphioxys f. muelleri, Pinnularia borealisvar.scalaris, Luticola aff. pusilla and Achnanthes muelleri. Biogeographically, the lichen-inhabiting diatom flora of the Ulu Peninsula is composed of cosmopolitan, Antarctic and endemic elements. The present study is the first focusing on the diversity of lichen-inhabiting diatom communities on James Ross Island, revealing the presence of a rather species rich diatom flora.
{"title":"Diatoms (Bacillariophyta) associated with lichens from Ulu Peninsula (James Ross Island, NE Antarctic Peninsula)","authors":"Hutňan Chattová, Barbora","doi":"10.5817/cpr2018-2-12","DOIUrl":"https://doi.org/10.5817/cpr2018-2-12","url":null,"abstract":"Since 2000, the entire Antarctic diatom flora is being revised using a more fine-grained taxonomy based on a better analysis and interpretation of the morphological and molecular observations. Despite the increased diatom research and efforts, the diversity and ecology of diatoms of lichen inhabiting flora of James Ross Island weren’t studied yet. To reveal the actual diatom diversity, samples were collected during February and March 2018 from lichens on the Ulu Peninsula, James Ross Island, a 2,450 km2 large island, situated in the north-western part of the Weddell Sea, close to the northern tip of the Antarctic Peninsula. The analysis of 29 lichen samples revealed the presence of 56 diatom taxa belonging to 17 genera. The most abundant species were Luticola muticopsis, Hantzschia amphioxys f. muelleri, Pinnularia borealisvar.scalaris, Luticola aff. pusilla and Achnanthes muelleri. Biogeographically, the lichen-inhabiting diatom flora of the Ulu Peninsula is composed of cosmopolitan, Antarctic and endemic elements. The present study is the first focusing on the diversity of lichen-inhabiting diatom communities on James Ross Island, revealing the presence of a rather species rich diatom flora.","PeriodicalId":37981,"journal":{"name":"Czech Polar Reports","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42424154","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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