Pub Date : 2017-12-01DOI: 10.1127/algol_stud/2017/0250
N. Rezzoum, A. Mouradi, T. Givernaud, L. Bennasser
For sustainable harvesting of wild stocks of economically important seaweed species, knowledge on the temporal variation of the standing stock biomass of the target species is an important prerequisite before any commercial harvesting concession can be granted. In this regard, a monthly in situ monitoring of the standing stock biomass of Laminaria ochroleuca (Bachelot de la Pylaie, 1824) was conducted during a two-year cycle at Sidi Bouzid located on the Moroccan Atlantic coast in the south of the city of El Jadida. Development of morphological parameters as proxy for growth i.e. blade length (L; cm), stipe length (S; cm) and dry biomass (kg.m-2) were monitored and measured. The shortest blade length was recorded in January 2004 and 2005 respectively (51.1 and 60 cm), the maximum was recorded in June 2004 and 2005 respectively (103.2 and 121.6 cm). Minimum biomasses are recorded in January of the two cycles of growth, it is about 0.60 kg.m-2 in 2004 and 0.98 kg.m-2 in 2005, the highest biomasses are recorded in May–June 2004 (1.9 kg.m-2) and in August for the year 2005 (3.9 kg.m-2). Individuals found in June 2005 have shorter stipe (8.21 cm) while maximum stipe length was recorded on October 2005 (22.8 cm). Mean yearly densities of L. ochroleuca were 34 and 32 plants/m² in 2004 and 2005 respectively. Therefore, the exploitation of this species should be carried out from June with harvest period reduced to a maximum of 2 months to allow the algae to grow in autumn.
为了可持续地捕捞具有重要经济意义的海藻物种的野生种群，了解目标物种的现存种群生物量的时间变化是授予任何商业捕捞特许权之前的重要先决条件。在这方面，在El Jadida市南部摩洛哥大西洋海岸的Sidi Bouzid，以两年为周期，每月对Laminaria ochloruca的现存种群生物量进行现场监测（Bachelot de la Pylaie，1824）。监测和测量了作为生长指标的形态参数的发展，即叶片长度（L；cm）、菌柄长度（S；cm）和干生物量（kg.m-2）。最短的叶片长度分别记录在2004年1月和2005年1月（51.1厘米和60厘米），最大的叶片长度记录分别在2004年和2005年6月（103.2厘米和121.6厘米）。在两个生长周期的1月记录的生物量最小，2004年约为0.60 kg.m-2，2005年约为0.98 kg.m-2。2004年5月至6月记录的最高生物量（1.9 kg.m-2）和2005年8月记录的最大生物量 2005年6月发现的个体柄较短（8.21厘米），而2005年10月记录的最大柄长（22.8厘米）。2004年和2005年的年平均密度分别为34株/m²和32株/m²。因此，该物种的开采应从6月开始，收获期最长应缩短至2个月，以便藻类在秋季生长。
{"title":"Temporal variation of Laminaria ochroleuca Bachelot de la Pylaie (Laminariales, Phaeophyceae) biomass on the Moroccan Atlantic coast: Implication for commercial harvesting","authors":"N. Rezzoum, A. Mouradi, T. Givernaud, L. Bennasser","doi":"10.1127/algol_stud/2017/0250","DOIUrl":"https://doi.org/10.1127/algol_stud/2017/0250","url":null,"abstract":"For sustainable harvesting of wild stocks of economically important seaweed species, knowledge on the temporal variation of the standing stock biomass of the target species is an important prerequisite before any commercial harvesting concession can be granted. In this regard, a monthly in situ monitoring of the standing stock biomass of Laminaria ochroleuca (Bachelot de la Pylaie, 1824) was conducted during a two-year cycle at Sidi Bouzid located on the Moroccan Atlantic coast in the south of the city of El Jadida. Development of morphological parameters as proxy for growth i.e. blade length (L; cm), stipe length (S; cm) and dry biomass (kg.m-2) were monitored and measured. The shortest blade length was recorded in January 2004 and 2005 respectively (51.1 and 60 cm), the maximum was recorded in June 2004 and 2005 respectively (103.2 and 121.6 cm). Minimum biomasses are recorded in January of the two cycles of growth, it is about 0.60 kg.m-2 in 2004 and 0.98 kg.m-2 in 2005, the highest biomasses are recorded in May–June 2004 (1.9 kg.m-2) and in August for the year 2005 \u2028(3.9 kg.m-2). Individuals found in June 2005 have shorter stipe (8.21 cm) while maximum stipe length was recorded on October 2005 (22.8 cm). Mean yearly densities of L. ochroleuca were 34 and 32 plants/m² in 2004 and 2005 respectively. Therefore, the exploitation of this species should be carried out from June with harvest period reduced to a maximum of 2 months to allow the algae to grow in autumn.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"153 1","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44087189","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 : 2017-12-01DOI: 10.1127/ALGOL_STUD/2017/0280
Silke Ammermann, H. Hillebrand, N. Rosenfeld, E. Rhiel
Abstract: The feeding behavior of the dinoflagellate Oxyrrhis marina with the prasinophyte Pyramimonas grossii as prey was studied in order i) to determine the ingestion rate for this armed microalga, ii) to survey the impact and fate of ejectisomes discharged within predatory cells, and iii) to check if birefringent bodies occur in both, starved and fed Oxyrrhis cells. Oxyr-rhis which was grown to stationary phase and then added to cultures of Pyramimonas captured and digested more than 95% of the prasinophyte within ten days. The decline of non-digested Pyramimonas cells monitored by regular cell counting using light microscopy, was also measured by fluorescence emission spectroscopy and registered by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Transmission electron microscopy revealed that the ejectisomes of Pyramimonas which were discharged within the food vacuole did not harm Oxyrrhis. Mainly the body scales and the ejectisomes were not digested but excreted. Both, starved and fed Oxyrrhis cells contained birefringent bodies. Besides the longitudinal banding, a faint and rather oblique running striation was registered for them.
{"title":"On the predatory behavior of Oxyrrhis marina (Dinophyceae) feeding on Pyramimonas grossii (Prasinophyceae)","authors":"Silke Ammermann, H. Hillebrand, N. Rosenfeld, E. Rhiel","doi":"10.1127/ALGOL_STUD/2017/0280","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2017/0280","url":null,"abstract":"Abstract: \u2029The feeding behavior of the dinoflagellate Oxyrrhis marina with the prasinophyte Pyramimonas grossii as prey was studied in order i) to determine the ingestion rate for this armed microalga, ii) to survey the impact and fate of ejectisomes discharged within predatory cells, and iii) to check if birefringent bodies occur in both, starved and fed Oxyrrhis cells. Oxyr-rhis which was grown to stationary phase and then added to cultures of Pyramimonas captured and digested more than 95% of the prasinophyte within ten days. The decline of non-digested Pyramimonas cells monitored by regular cell counting using light microscopy, was also measured by fluorescence emission spectroscopy and registered by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Transmission electron microscopy revealed that the ejectisomes of Pyramimonas which were discharged within the food vacuole did not harm Oxyrrhis. Mainly the body scales and the ejectisomes were not digested but excreted. Both, starved and fed Oxyrrhis cells contained birefringent bodies. Besides the longitudinal banding, a faint and rather oblique running striation was registered for them.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"153 1","pages":"41-58"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44893352","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 : 2017-12-01DOI: 10.1127/ALGOL_STUD/2016/0262
S. Karaa, J. Báez, A. Flores‐Moya, I. Jribi, M. Bradai
Abstract This is the first record of the red alga Polysiphonia carettia Hollenberg (Rhodomeleaceae) in the Gulf of Gabes, Tunisia (Mediterranean Sea). This species was first described growing on the carapace of the loggerhead sea turtle Caretta caretta (L.) from Santa Catalina Island, California, USA. In the Mediterranean, it was reported only from two loggerhead turtles captured by a Spanish longline vessel. The morphology, habitat and geographical distribution of P. carettia were examined.
{"title":"First record of epizoic algae Polysiphonia carettia Hollenberg, on loggerhead sea turtles in the Gulf of Gabès (Central Mediterranean Sea)","authors":"S. Karaa, J. Báez, A. Flores‐Moya, I. Jribi, M. Bradai","doi":"10.1127/ALGOL_STUD/2016/0262","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2016/0262","url":null,"abstract":"Abstract This is the first record of the red alga Polysiphonia carettia Hollenberg (Rhodomeleaceae) in the Gulf of Gabes, Tunisia (Mediterranean Sea). This species was first described growing on the carapace of the loggerhead sea turtle Caretta caretta (L.) from Santa Catalina Island, California, USA. In the Mediterranean, it was reported only from two loggerhead turtles captured by a Spanish longline vessel. The morphology, habitat and geographical distribution of P. carettia were examined.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"153 1","pages":"35-39"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43351270","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 : 2017-12-01DOI: 10.1127/ALGOL_STUD/2017/0295
C. Barragán, L. Ector, C. E. Wetzel
With 44 figures and 2 tables Abstract: The analysis of samples taken in different aerial microhabitats in Europe (Germany and Luxembourg) revealed the presence of a new and interesting small-celled naviculoid diatom species. Based on detailed light and scanning electron microscopy, one taxon previously misidentified as Sellaphora saugerresii is here described as Mayamaea petersenii sp. nov. The ecological preferences and a detailed analysis of its frustule ultrastructure lead to propose its generic placement in Mayamaea, followed by a discussion concerning key characters of the genera Sellaphora, Eolimna and Chamaepinnularia.
{"title":"Mayamaea petersenii sp. nov., a new diatom from European aerial habitats and a brief appraisal on the morphological diversity of the genus","authors":"C. Barragán, L. Ector, C. E. Wetzel","doi":"10.1127/ALGOL_STUD/2017/0295","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2017/0295","url":null,"abstract":"With 44 figures and 2 tables Abstract: The analysis of samples taken in different aerial microhabitats in Europe (Germany and Luxembourg) revealed the presence of a new and interesting small-celled naviculoid diatom species. Based on detailed light and scanning electron microscopy, one taxon previously misidentified as Sellaphora saugerresii is here described as Mayamaea petersenii sp. nov. The ecological preferences and a detailed analysis of its frustule ultrastructure lead to propose its generic placement in Mayamaea, followed by a discussion concerning key characters of the genera Sellaphora, Eolimna and Chamaepinnularia.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"153 1","pages":"71-87"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46587806","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 : 2017-12-01DOI: 10.1127/ALGOL_STUD/2017/0290
A. Dahmen, Hannah M. Houle, Jeffrey D. Leblond
Ecology and Evolution Group, Department of Biology, P.O. Box 60, Middle Tennessee State University, Murfreesboro, TN 37132 USA With 1 figure and 1 table Abstract: The genus Acetabularia represents a group of historically important, macroscopic, single-celled green algae initially used by Joachim Hammerling to demonstrate localization of genetic material within the nucleus of a cell (by grafting one species onto another and allowing it to regenerate its original form). Acetabularia, and the related genus Acicularia, are considered to be “living fossils” within the family Polyphysaceae because of their long and uninterrupted fossil record, and, as such, are important taxa in the evolutionary progression of green algae (and plants). To date, there is just a single published study on the sterols of Acetabularia mediterranea. Sterols, tetracyclic lipids which act to reinforce eukaryotic plasma membranes, are often used as chemotaxonomic indicators to assess relationships between eukaryotes. Examination of sterols within Acetabularia and Acicularia may help further identify an ancestral set of sterols that has since radiated throughout many green algae. Two C28 and three C29 sterols commonly found in green algae, all with Δ5 unsaturations and with the dominant one being 24-ethylcholest-5-en-3β-ol, were observed in four species of Acetabularia and one of Acicularia. The chemotaxonomic and evolutionary aspects of this finding are discussed herein.
{"title":"Free sterols of the historically important green algal genera, Acetabularia and Acicularia (Polyphysaceae): a modern interpretation","authors":"A. Dahmen, Hannah M. Houle, Jeffrey D. Leblond","doi":"10.1127/ALGOL_STUD/2017/0290","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2017/0290","url":null,"abstract":"Ecology and Evolution Group, Department of Biology, P.O. Box 60, Middle Tennessee State University, Murfreesboro, TN 37132 USA With 1 figure and 1 table Abstract: The genus Acetabularia represents a group of historically important, macroscopic, single-celled green algae initially used by Joachim Hammerling to demonstrate localization of genetic material within the nucleus of a cell (by grafting one species onto another and allowing it to regenerate its original form). Acetabularia, and the related genus Acicularia, are considered to be “living fossils” within the family Polyphysaceae because of their long and uninterrupted fossil record, and, as such, are important taxa in the evolutionary progression of green algae (and plants). To date, there is just a single published study on the sterols of Acetabularia mediterranea. Sterols, tetracyclic lipids which act to reinforce eukaryotic plasma membranes, are often used as chemotaxonomic indicators to assess relationships between eukaryotes. Examination of sterols within Acetabularia and Acicularia may help further identify an ancestral set of sterols that has since radiated throughout many green algae. Two C28 and three C29 sterols commonly found in green algae, all with Δ5 unsaturations and with the dominant one being 24-ethylcholest-5-en-3β-ol, were observed in four species of Acetabularia and one of Acicularia. The chemotaxonomic and evolutionary aspects of this finding are discussed herein.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"153 1","pages":"59-70"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42465792","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 : 2017-12-01DOI: 10.1127/ALGOL_STUD/2016/0264
N. Ferrer, E. Cáceres
Abstract: In this study five species of Spirogyra (Zygnemataceae) from lentic (pools, lagoons, lakes) and lotic (stream) habitats in the south of Buenos Aires province, Argentina, are described and illustrated in detail, with precision about their vegetative morphology, conjugation and zygospore ornamentation. Two of the species, S. ellipsospora and S. hyalina, are newly recorded for Argentina and the other three, i.e. S. quadrilaminata, S. maxima and S. majuscula, were previously mentioned with imprecise references and no illustrations for this country.
摘要/ Abstract摘要:本文对阿根廷布宜诺斯艾利亚省南部的5种水蛛(Zygnemataceae)进行了详细的描述和说明，并对它们的营养形态、接合和接合孢子的装饰进行了精确的描述。其中2种(S. ellipsospora)和S. hyalina是阿根廷新记录的，另外3种(S. quadrilaminata, S. maxima和S. majuscula)以前提到过，但没有精确的参考资料，也没有说明该国的情况。
{"title":"Vegetative and reproductive morphology of five Spirogyra species (Zygnematales, Charophyta) in Argentina","authors":"N. Ferrer, E. Cáceres","doi":"10.1127/ALGOL_STUD/2016/0264","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2016/0264","url":null,"abstract":"Abstract: In this study five species of Spirogyra (Zygnemataceae) from lentic (pools, lagoons, lakes) and lotic (stream) habitats in the south of Buenos Aires province, Argentina, are described and illustrated in detail, with precision about their vegetative morphology, conjugation and zygospore ornamentation. Two of the species, S. ellipsospora and S. hyalina, are newly recorded for Argentina and the other three, i.e. S. quadrilaminata, S. maxima and S. majuscula, were previously mentioned with imprecise references and no illustrations for this country.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"153 1","pages":"17-34"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43115038","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 : 2016-09-01DOI: 10.1127/ALGOL_STUD/2016/0269
K. Zacher, Valentina Savaglia, I. Bartsch
The brown algae Desmarestia menziesii and D. anceps form dense underwater forests at the Western Antarctic Peninsula (WAP) in the upper to mid subtidal and play an important role in this coastal ecosystem. Seawater temperatures at the WAP increased by about 2 °C in the last 50 years and probably will rise further in future due to global warming. This may have consequences for the physiological performance and community interactions of these cold water adapted algae. In laboratory experiments with culture material we investigated the influence of increased temperatures on the photosynthetic response, growth and interspecific competition of both species. Increased temperature (5 °C) induced a higher growth rate of D. anceps and a higher optimum quantum yield of photosynthesis in both species compared to 0 °C. Neither interspecific competition nor interactions between competition and temperature were detected. The photosynthetic performance (rETRmax, α and Ek) of D. menziesii was significantly more often affected by temperature increases than of D. anceps. It was shown that a temperature increase from 0 °C to 5 °C was not harmful for both Desmarestia species in this set-up. Generally, growth of D. menziesii was very low possibly reflecting a dormancy state under continuous long-day conditions and thereby may have masked the influence of temperature on growth. In order to determine realistic survival thresholds of these key species of the Antarctic coastal ecosystem under global change scenarios, further multifactorial experiments are of great importance, including field material, different algal life stages and reproductive processes.
{"title":"Effects of temperature and interspecific competition on growth and photosynthesis of two endemic Antarctic Desmarestia species","authors":"K. Zacher, Valentina Savaglia, I. Bartsch","doi":"10.1127/ALGOL_STUD/2016/0269","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2016/0269","url":null,"abstract":"The brown algae Desmarestia menziesii and D. anceps form dense underwater forests \u0000at the Western Antarctic Peninsula (WAP) in the upper to mid subtidal and play an important \u0000role in this coastal ecosystem. Seawater temperatures at the WAP increased by about 2 °C \u0000in the last 50 years and probably will rise further in future due to global warming. This may \u0000have consequences for the physiological performance and community interactions of these \u0000cold water adapted algae. In laboratory experiments with culture material we investigated the \u0000influence of increased temperatures on the photosynthetic response, growth and interspecific \u0000competition of both species. Increased temperature (5 °C) induced a higher growth rate of \u0000D. anceps and a higher optimum quantum yield of photosynthesis in both species compared to \u00000 °C. Neither interspecific competition nor interactions between competition and temperature \u0000were detected. The photosynthetic performance (rETRmax, α and Ek) of D. menziesii was significantly \u0000more often affected by temperature increases than of D. anceps. It was shown that a \u0000temperature increase from 0 °C to 5 °C was not harmful for both Desmarestia species in this \u0000set-up. Generally, growth of D. menziesii was very low possibly reflecting a dormancy state \u0000under continuous long-day conditions and thereby may have masked the influence of temperature \u0000on growth. In order to determine realistic survival thresholds of these key species of \u0000the Antarctic coastal ecosystem under global change scenarios, further multifactorial experiments \u0000are of great importance, including field material, different algal life stages and reproductive \u0000processes.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"151 1","pages":"103-122"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1127/ALGOL_STUD/2016/0269","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64050615","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 : 2016-09-01DOI: 10.1127/ALGOL_STUD/2016/0259
R. Rautenberger, K. Bischof
Ultraviolet (UV) radiation is a significant stress factor that harms life in both terrestrial and aquatic ecosystems in Antarctica. In summer (January–February), ground-level solar radiation regimes at the Antarctic Carlini Station (62°14'S, 58°40'W) on King George Island (South Shetland Islands) can be highly variable, depending on the presence of clouds. Spectrally-resolved underwater radiation regimes were measured at three study sites in the inner and outer Potter Cove nearby Carlini Station. The clear waters at Penon de Pesca allowed PAR, UV-A and UV-B radiation to penetrate deeply into the water column, expressed by z1% (i. e. 1%-depths) at 23–25 m, 20–22 m and 13–16 m, respectively, as well as by low attenuation coefficients of downward radiation (Kd). In contrast, turbid waters in the inner Potter Cove and at Penon Uno reduced the penetration of these three wavebands significantly. The photo-physiological mechanisms allowing macroalgae to acclimate to the incident gradients of PAR and UV radiation at Penon de Pesca were further elaborated by assessing photo-physiological data on the brown macroalga Desmarestia menziesii (Phaeophyceae), exposed to a PAR range between 15 and 130 μ mol photons m-2 s-1, either in the presence or absence of UV radiation (10.3 W m -2 UV-A and 0.73 W m -2 UV-B). PAM-fluorometry-based measurements revealed a similar decrease of the optimum quantum yield of photosystem II (PSII) under both PAR and UV radiation and a stronger effect of PAR over UV radiation in the regulation of maximum photosynthetic electron transport rate (ETRmax) as well as the photosynthetic light saturation (Ek). The down-regulation of the photochemistry of PSII by PAR as well as the reduction in the photosynthetic electron transport capacity (i.e.ETRmax) indicate important photoprotective mechanisms allowing D. menziesii to response effectively to a combination of PAR and UV stress in their upper subtidal habitat.
紫外线辐射是危害南极洲陆地和水生生态系统生命的一个重要应激因素。在夏季(1月至2月)，位于乔治国王岛(南设得兰群岛)的南极Carlini站(62°14'S, 58°40'W)的地面太阳辐射状况可能会高度变化，这取决于云层的存在。在靠近Carlini站的波特湾内外三个研究地点测量了光谱分辨的水下辐射状态。Penon de Pesca的清澈水域允许PAR、UV-A和UV-B辐射深入水柱，分别以23-25 m、20-22 m和13-16 m处的z1%(即1%深度)表示，并以较低的向下辐射衰减系数Kd表示。相比之下，波特湾内部和佩农乌诺的浑浊水域显著减少了这三个波段的穿透。通过评估褐藻Desmarestia menziesii (Phaeophyceae)的光生理数据，进一步阐述了Penon de Pesca大型藻类适应PAR和UV辐射入射梯度的光生理机制。在存在或不存在紫外线辐射(10.3 W m-2 UV- a和0.73 W m-2 UV- b)的情况下，暴露在15 ~ 130 μ mol光子m-2 s-1的PAR范围内。基于pam -荧光测量的结果显示，在PAR和UV辐射下，光系统II (PSII)的最佳量子产率都有类似的下降，并且PAR对最大光合电子传递速率(ETRmax)和光合光饱和度(Ek)的调节作用强于UV辐射。PAR对PSII光化学反应的下调以及光合电子传递能力(etrmax)的降低表明了门齐氏d.m enziesii在其潮下上层生境中有效响应PAR和UV联合胁迫的重要光保护机制。
{"title":"Dynamic summer solar radiation in Antarctic coastal ecosystems and its effects on photosyn thesis of the endemic Antarctic brown macroalga Desmarestia menziesii (Phaeophyceae)","authors":"R. Rautenberger, K. Bischof","doi":"10.1127/ALGOL_STUD/2016/0259","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2016/0259","url":null,"abstract":"Ultraviolet (UV) radiation is a significant stress factor that harms life in both terrestrial and aquatic ecosystems in Antarctica. In summer (January–February), ground-level solar radiation regimes at the Antarctic Carlini Station (62°14'S, 58°40'W) on King George Island (South Shetland Islands) can be highly variable, depending on the presence of clouds. Spectrally-resolved underwater radiation regimes were measured at three study sites in the inner and outer Potter Cove nearby Carlini Station. The clear waters at Penon de Pesca allowed PAR, UV-A and UV-B radiation to penetrate deeply into the water column, expressed by z1% (i. e. 1%-depths) at 23–25 m, 20–22 m and 13–16 m, respectively, as well as by low attenuation coefficients of downward radiation (Kd). In contrast, turbid waters in the inner Potter Cove and at Penon Uno reduced the penetration of these three wavebands significantly. The photo-physiological mechanisms allowing macroalgae to acclimate to the incident gradients of PAR and UV radiation at Penon de Pesca were further elaborated by assessing photo-physiological data on the brown macroalga Desmarestia menziesii (Phaeophyceae), exposed to a PAR range between 15 and 130 μ mol photons m-2 s-1, either in the presence or absence of UV radiation (10.3 W m -2 UV-A and 0.73 W m -2 UV-B). PAM-fluorometry-based measurements revealed a similar decrease of the optimum quantum yield of photosystem II (PSII) under both PAR and UV radiation and a stronger effect of PAR over UV radiation in the regulation of maximum photosynthetic electron transport rate (ETRmax) as well as the photosynthetic light saturation (Ek). The down-regulation of the photochemistry of PSII by PAR as well as the reduction in the photosynthetic electron transport capacity (i.e.ETRmax) indicate important photoprotective mechanisms allowing D. menziesii to response effectively to a combination of PAR and UV stress in their upper subtidal habitat.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"151 1","pages":"123-150"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1127/ALGOL_STUD/2016/0259","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64050353","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 : 2016-09-01DOI: 10.1127/ALGOL_STUD/2016/0245
Sigrid Pfaff, Nadine Borchhardt, J. Boy, U. Karsten, Lydia Gustavs
The genus Coccomyxa is frequently present in biological soil crusts from temperate regions but has also been found in Antarctic soils. Strain NIES 2166 (Coccomyxa subellipsoidea) from continental South Victoria Land is described as a model organism for cold adaptation (Blanc et al. 2012) although it has been cultivated for more than 50 years under artificial conditions. In order to test whether this isolate still kept physiological traits for Antarctic conditions or exhibited acclimation/adaptation to culturing, it was ecophysiologically compared with three recently isolated Coccomyxa strains from soil samples collected at the Antarctic Peninsula. Additionally, the investigated strains were tested for potential endemism. Molecular analysis based on ITS rDNA identified the three newly isolated strains also as C. subellipsoidea. The effective quantum yield of photosynthesis was examined during controlled short-term desiccation (at relative air humidity c. 10%) and after rehydration. Growth rates were determined over a temperature gradient from 4.6 to 34.8 °C. The results indicate cold tolerance and drought tolerance among all tested strains which are slightly more developed in the continental strain NIES 2166 although 50 years passed since isolation. Therefore it is assumed that strain NIES 2166 can still be recommended to test traits of cold adaptation but psychrophilic behavior, and therefore endemism, can be excluded among all str
{"title":"Desiccation tolerance and growth-temperature requirements of Coccomyxa (Trebouxiophyceae, Chlorophyta) strains from Antarctic biological soil crusts","authors":"Sigrid Pfaff, Nadine Borchhardt, J. Boy, U. Karsten, Lydia Gustavs","doi":"10.1127/ALGOL_STUD/2016/0245","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2016/0245","url":null,"abstract":"The genus Coccomyxa is frequently present in biological soil crusts from temperate regions but has also been found in Antarctic soils. Strain NIES 2166 (Coccomyxa subellipsoidea) from continental South Victoria Land is described as a model organism for cold adaptation (Blanc et al. 2012) although it has been cultivated for more than 50 years under artificial conditions. In order to test whether this isolate still kept physiological traits for Antarctic conditions or exhibited acclimation/adaptation to culturing, it was ecophysiologically compared with three recently isolated Coccomyxa strains from soil samples collected at the Antarctic Peninsula. Additionally, the investigated strains were tested for potential endemism. Molecular analysis based on ITS rDNA identified the three newly isolated strains also as C. subellipsoidea. The effective quantum yield of photosynthesis was examined during controlled short-term desiccation (at relative air humidity c. 10%) and after rehydration. Growth rates were determined over a temperature gradient from 4.6 to 34.8 °C. The results indicate cold tolerance and drought tolerance among all tested strains which are slightly more developed in the continental strain NIES 2166 although 50 years passed since isolation. Therefore it is assumed that strain NIES 2166 can still be recommended to test traits of cold adaptation but psychrophilic behavior, and therefore endemism, can be excluded among all str","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"151 1","pages":"3-19"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1127/ALGOL_STUD/2016/0245","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64049925","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 : 2016-09-01DOI: 10.1127/ALGOL_STUD/2016/0254
C. Colesie, B. Büdel, A. Green
In the McMurdo Dry Valleys, located in Southern Victoria Land, Antarctica, endolithic communities are important photoautotrophic primary producers. Being poikilohydric organisms their active time and carbon fixation rates rely on local water availability. In Antarctica the parallel variation in the severity of the thermal and hydric environment makes simple transect and gradient based modelling complicated. Here we interpret samples collected over several seasons in terms of rock type (sandstone, marble and granite) and location (distance from sea, altitude) on the colonization, species composition, chlorophyll content, biomass as well as stable carbon isotopic composition and 14 C age of the endolithic communities. Distance from coast was highly correlated with altitude of the sampling locations and this complicated disentangling of climatic drivers. Nevertheless, stable carbon isotopic composition allowed insight into hydration regime and 14C radiocarbon age into productivity. Endolithic communities in sandstone at high altitude sites have higher biomass but are less often active than communities in lowland granite.
{"title":"Endolithic communities in the McMurdo Dry Valleys: biomass, turnover, cyanobacteria and location – a preliminary insight","authors":"C. Colesie, B. Büdel, A. Green","doi":"10.1127/ALGOL_STUD/2016/0254","DOIUrl":"https://doi.org/10.1127/ALGOL_STUD/2016/0254","url":null,"abstract":"In the McMurdo Dry Valleys, located in Southern Victoria Land, Antarctica, endolithic communities are important photoautotrophic primary producers. Being poikilohydric organisms their active time and carbon fixation rates rely on local water availability. In Antarctica the parallel variation in the severity of the thermal and hydric environment makes simple transect and gradient based modelling complicated. Here we interpret samples collected over several seasons in terms of rock type (sandstone, marble and granite) and location (distance from sea, altitude) on the colonization, species composition, chlorophyll content, biomass as well as stable carbon isotopic composition and 14 C age of the endolithic communities. Distance from coast was highly correlated with altitude of the sampling locations and this complicated disentangling of climatic drivers. Nevertheless, stable carbon isotopic composition allowed insight into hydration regime and 14C radiocarbon age into productivity. Endolithic communities in sandstone at high altitude sites have higher biomass but are less often active than communities in lowland granite.","PeriodicalId":90782,"journal":{"name":"Algological studies (Stuttgart, Germany : 2007)","volume":"151 1","pages":"51-68"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64050072","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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