S. Armeli Minicante, R. Piredda, S. Finotto, F. Bernardi Aubry, F. Acri, A. Pugnetti, A. Zingone
Transitional waters are subject to a high degree of variability in space and time. In this study, protist plankton communities of the Lagoon of Venice were compared among four sites characterised by different environmental conditions with a metabarcoding approach. High throughput sequencing (HTS) of the V4-18S rDNA fragment in 32 samples collected on four dates, from April 2016 to February 2017, produced 1,137,113 reads, which were grouped into 4058 OTUs at 97% similarity. Bacillariophyta and Ciliophora were the most abundant groups in the entire dataset in terms of read number (27.6% and 16.6%, respectively), followed by Dinophyta (10.9%), Cryptophyceae (9.7%), and Syndiniales (6.1%). The contribution of protist groups markedly varied across the seasons, but spatial differences were also recorded in the lagoon. In April, a higher contribution of Bacillariophyta characterized St1 and 5 (68.0% and 61.1%), whereas Sts2 and 3 showed a higher percentage of Ciliophora (18.6 and 23.4%, respectively) and dinoflagellates (10.3 and 7.7%). In July, diatom blooms occurred at Sts1, 2 and 3, with some differences in the dominant species. At St2 Dinophyta reached the highest contribution of the whole sampling period in the area (30.6%), while St5 was quite distinct, with a low contribution of diatoms and a dominance of Ciliophora (34.0%) and Trebouxiophyceae (36.4%). All the stations in November were characterized by relatively high abundance of Ciliophora (21.4-51.9%). In February, diatom contribution was relevant only at St5 (29.3%), Teleaulax acuta peaked at St3 (ca. 36%), Syndiniales at St2 (38.8%) and Dictyochophyceae at St1 (24.2%). The α-diversity indexes (observed OTUs, Shannon and Pielou evenness) showed a high variability over space and time. Diversity and community composition were rather similar between the intermediate and deeper Sts2 and 3 on all sampling dates whereas they at time differed between the landward and shallow Sts1 and 5. While the most marked differences occurred over the temporal scale, the depth of the station and the relatedness with the external marine coastal environment appear to play a major role in the spatial distribution of protist communities within the lagoon. Overall, the quite stable spatial differences in spite of the significant seasonal changes reflected the hydro-geological heterogeneity of the sampling stations, indicating a major influence of the landsea gradient in the lagoon. No n-c om me rci al us e o nly S. Armeli Minicante et al. 36 the lagoon and the adjacent marine waters of the Gulf of Venice (Armeli Minicante et al., 2019). In spite of potential pitfalls of the metabarcoding approach, which can poorly resolve the diversity of some taxa (Piredda et al. 2018) or miss them altogether (Massana et al., 2015), the latter study based on the V4-18S rRNA metabarcodes largely increased the diversity knowledge not only for protists that have traditionally been neglected (i.e., heterotrophs, parasites, picoeukaryote
{"title":"Spatial diversity of planktonic protists in the Lagoon of Venice (LTER-Italy) based on 18S rDNA","authors":"S. Armeli Minicante, R. Piredda, S. Finotto, F. Bernardi Aubry, F. Acri, A. Pugnetti, A. Zingone","doi":"10.4081/aiol.2020.8961","DOIUrl":"https://doi.org/10.4081/aiol.2020.8961","url":null,"abstract":"Transitional waters are subject to a high degree of variability in space and time. In this study, protist plankton communities of the Lagoon of Venice were compared among four sites characterised by different environmental conditions with a metabarcoding approach. High throughput sequencing (HTS) of the V4-18S rDNA fragment in 32 samples collected on four dates, from April 2016 to February 2017, produced 1,137,113 reads, which were grouped into 4058 OTUs at 97% similarity. Bacillariophyta and Ciliophora were the most abundant groups in the entire dataset in terms of read number (27.6% and 16.6%, respectively), followed by Dinophyta (10.9%), Cryptophyceae (9.7%), and Syndiniales (6.1%). The contribution of protist groups markedly varied across the seasons, but spatial differences were also recorded in the lagoon. In April, a higher contribution of Bacillariophyta characterized St1 and 5 (68.0% and 61.1%), whereas Sts2 and 3 showed a higher percentage of Ciliophora (18.6 and 23.4%, respectively) and dinoflagellates (10.3 and 7.7%). In July, diatom blooms occurred at Sts1, 2 and 3, with some differences in the dominant species. At St2 Dinophyta reached the highest contribution of the whole sampling period in the area (30.6%), while St5 was quite distinct, with a low contribution of diatoms and a dominance of Ciliophora (34.0%) and Trebouxiophyceae (36.4%). All the stations in November were characterized by relatively high abundance of Ciliophora (21.4-51.9%). In February, diatom contribution was relevant only at St5 (29.3%), Teleaulax acuta peaked at St3 (ca. 36%), Syndiniales at St2 (38.8%) and Dictyochophyceae at St1 (24.2%). The α-diversity indexes (observed OTUs, Shannon and Pielou evenness) showed a high variability over space and time. Diversity and community composition were rather similar between the intermediate and deeper Sts2 and 3 on all sampling dates whereas they at time differed between the landward and shallow Sts1 and 5. While the most marked differences occurred over the temporal scale, the depth of the station and the relatedness with the external marine coastal environment appear to play a major role in the spatial distribution of protist communities within the lagoon. Overall, the quite stable spatial differences in spite of the significant seasonal changes reflected the hydro-geological heterogeneity of the sampling stations, indicating a major influence of the landsea gradient in the lagoon. No n-c om me rci al us e o nly S. Armeli Minicante et al. 36 the lagoon and the adjacent marine waters of the Gulf of Venice (Armeli Minicante et al., 2019). In spite of potential pitfalls of the metabarcoding approach, which can poorly resolve the diversity of some taxa (Piredda et al. 2018) or miss them altogether (Massana et al., 2015), the latter study based on the V4-18S rRNA metabarcodes largely increased the diversity knowledge not only for protists that have traditionally been neglected (i.e., heterotrophs, parasites, picoeukaryote","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/aiol.2020.8961","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43576958","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}
D. Moccia, L. Salvadori, S. Ferrari, A. Carucci, A. Pusceddu
River ecosystems are characterised by a naturally high level of hydrodynamic perturbations which create aquatic-terrestrial habitats indispensable for many species, as well as for the human beings’ welfare. Environmental degradation and habitat loss caused by increasing anthropogenic pressures and global change affect freshwater aquatic ecosystems worldwide and have caused changes in water flow regimes and channels morphologies. These, in turn, decreased the natural flow capacity and reduced habitat availability, thus causing severe degradation of rivers’ ecological integrity. The ecological flow (e-flow) is commonly intended as the quantity, timing, duration, frequency and quality of water flows required to sustain freshwater, estuarine and near shore ecosystems and the human livelihoods and well being. Maintaining the e-flow represents a potential tool for restoring and managing river ecosystems, to preserve the autochthonous living communities, along with environmental services and cultural/societal values. In the last decade, methods for the determination of the e-flow in European rivers moved from a simply hydrological approach towards establishing a linkage between the hydrological regime and the good ecological status (GES) of the water bodies, as identified by the European Water Framework Directive (WFD; 2000/60/EC). Each Member State is required to implement and integrate into the River Basin Management Plans (RBMP) a methodology for the determination of the e-flow, ensuring that rivers can achieve and maintain the GES. The competent river basin authorities have thus to ascertain whether national methodologies can be applied to different river typologies and basin environment characteristics. In this context, we narratively review the e-flow assessments in the heterogeneous Italian territory, in particular on a water scant region such as Sardinia, by analysing laws, guidelines and focusing on study cases conducted with micro and meso-scale hydraulic-habitat approaches. In the sight of a more ecological-based application of national e-flow policy, we suggest that meso-habitat methods provide a valuable tool to overcome several limitations of current e-flow implementation in the Italian territory. However, to face future challenges, such as climate change adaptation, we stress the need for further experimental studies to update water management plans with greater attention for nature conservation. N n-c om me rci al us e o nly Implementation of the EU ecological flow policy in Italy with a focus on Sardinia 23 release from dams and other types of derivation (Acreman et al., 2016). The environmental flow (e-flow) is commonly intended as the quantity, timing, duration, frequency and quality of water flows required to sustain freshwater, estuarine and near shore ecosystems and the human livelihoods and well being (Tharme, 2000). The concept of e-flow has been discussed for more than 40 years (Tharme, 2003; Acreman and Dunbar, 2004; King and B
河流生态系统的特点是自然高度的水动力扰动，为许多物种和人类的福祉创造了不可或缺的水生-陆地栖息地。人为压力的增加和全球变化造成的环境退化和生境丧失影响着全世界的淡水水生生态系统，并引起水流体制和河道形态的变化。这些反过来又降低了自然流量，减少了栖息地的可用性，从而导致河流生态完整性的严重退化。生态流量(e-flow)通常是指维持淡水、河口和近岸生态系统以及人类生计和福祉所需的水流的数量、时间、持续时间、频率和质量。保持电子流量是恢复和管理河流生态系统的潜在工具，可以保护当地的生活社区，以及环境服务和文化/社会价值。在过去十年中，确定欧洲河流电子流量的方法从简单的水文方法转向建立水文制度与水体良好生态状况(GES)之间的联系，如欧洲水框架指令(WFD;2000/60 / EC)。每个会员国都必须执行一种确定河流流量的方法，并将其纳入《流域管理计划》，以确保河流能够达到并维持全球生态指标。因此，流域主管当局必须确定国家方法是否适用于不同的河流类型和流域环境特征。在这种情况下，我们叙叙性地回顾了意大利异质领土上的电子流量评估，特别是在像撒丁岛这样的缺水地区，通过分析法律、指导方针，并专注于用微尺度和中尺度水力生境方法进行的研究案例。从更注重生态的国家电子流量政策应用的角度来看，我们建议中生境方法为克服当前意大利境内电子流量实施的几个限制提供了一个有价值的工具。然而，面对未来的挑战，如适应气候变化，我们强调需要进一步的实验研究来更新水管理计划，更多地关注自然保护。在意大利实施欧盟生态流量政策，重点关注撒丁岛23号大坝和其他类型的衍生项目(Acreman et al.， 2016)。环境流量(e-flow)通常是指维持淡水、河口和近岸生态系统以及人类生计和福祉所需的水流的数量、时间、持续时间、频率和质量(Tharme, 2000)。电子流的概念已经讨论了40多年(Tharme, 2003;Acreman and Dunbar, 2004;金和布朗，2006;Poff and Matthews, 2013;Acreman, 2016)，现在已经被几个国家和地区的水保护政策所认可，例如欧洲水框架指令(欧盟委员会，2015)，南非国家水法(Forslund等人，2009)和布里斯班宣言(Arthington等人，2018)。许多国家在更新水政策和法律时都纳入了电子流量规定(Le Quesne et al.， 2010)。在过去几年中，人们越来越多地认识到，为了成功地管理淡水生态系统，调和自然栖息地保护与供人类使用的淡水供应，需要以科学为基础的方法和要求来评估电子流量(Acreman and Dunbar, 2004)。鉴于当前气候变化导致的水文条件变化，实现这种权衡可能变得更加关键(Tonkin et al.， 2019)。Tharme(2003)确定了200种方法来评估水生物种和栖息地的水需求，并支持电子流量管理实践以实现生态和社会目标(另见Acreman和Dunbar 2004)。然而，到目前为止，仍然有一些限制因素限制了流动政策的成功实施，主要是由于机构能力、科学知识和监测资源的限制。Le Quesne等人对此进行了总结。
{"title":"Implementation of the EU ecological flow policy in Italy with a focus on Sardinia","authors":"D. Moccia, L. Salvadori, S. Ferrari, A. Carucci, A. Pusceddu","doi":"10.4081/aiol.2020.8781","DOIUrl":"https://doi.org/10.4081/aiol.2020.8781","url":null,"abstract":"River ecosystems are characterised by a naturally high level of hydrodynamic perturbations which create aquatic-terrestrial habitats indispensable for many species, as well as for the human beings’ welfare. Environmental degradation and habitat loss caused by increasing anthropogenic pressures and global change affect freshwater aquatic ecosystems worldwide and have caused changes in water flow regimes and channels morphologies. These, in turn, decreased the natural flow capacity and reduced habitat availability, thus causing severe degradation of rivers’ ecological integrity. The ecological flow (e-flow) is commonly intended as the quantity, timing, duration, frequency and quality of water flows required to sustain freshwater, estuarine and near shore ecosystems and the human livelihoods and well being. Maintaining the e-flow represents a potential tool for restoring and managing river ecosystems, to preserve the autochthonous living communities, along with environmental services and cultural/societal values. In the last decade, methods for the determination of the e-flow in European rivers moved from a simply hydrological approach towards establishing a linkage between the hydrological regime and the good ecological status (GES) of the water bodies, as identified by the European Water Framework Directive (WFD; 2000/60/EC). Each Member State is required to implement and integrate into the River Basin Management Plans (RBMP) a methodology for the determination of the e-flow, ensuring that rivers can achieve and maintain the GES. The competent river basin authorities have thus to ascertain whether national methodologies can be applied to different river typologies and basin environment characteristics. In this context, we narratively review the e-flow assessments in the heterogeneous Italian territory, in particular on a water scant region such as Sardinia, by analysing laws, guidelines and focusing on study cases conducted with micro and meso-scale hydraulic-habitat approaches. In the sight of a more ecological-based application of national e-flow policy, we suggest that meso-habitat methods provide a valuable tool to overcome several limitations of current e-flow implementation in the Italian territory. However, to face future challenges, such as climate change adaptation, we stress the need for further experimental studies to update water management plans with greater attention for nature conservation. N n-c om me rci al us e o nly Implementation of the EU ecological flow policy in Italy with a focus on Sardinia 23 release from dams and other types of derivation (Acreman et al., 2016). The environmental flow (e-flow) is commonly intended as the quantity, timing, duration, frequency and quality of water flows required to sustain freshwater, estuarine and near shore ecosystems and the human livelihoods and well being (Tharme, 2000). The concept of e-flow has been discussed for more than 40 years (Tharme, 2003; Acreman and Dunbar, 2004; King and B","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":"11 1","pages":"22-34"},"PeriodicalIF":0.0,"publicationDate":"2020-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/aiol.2020.8781","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43600885","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}
Cyanotoxins are a global concern in freshwaters and eutrophication and climate changes can have synergistic effects in exacerbating the problem. The deep perialpine lakes are a group of lakes of huge economic and naturalistic importance located at the border of the Alps. At the southern border of the Italian and Swiss Alps, the largest waterbodies include the lakes Garda, Iseo, Como, Lugano and Maggiore (Deep Subalpine Lakes, DSL). Together with eutrophication (during the 1960s and 1970s) and re-oligotrophication (from the 1990s onward) these lakes have been experiencing warming and increase of the water column stability. These changes had a strong impact on the phytoplankton (including cyanobacteria) community. Four DSL (lakes Garda, Iseo, Como and Lugano) have been studied with the aim of comparing their toxic potential. For one of them (Lake Garda) an 8 years survey was conducted, allowing a long-term trend analysis. Toxin analysis was conducted on a monthly basis by targeted LC-MS/MS. A screening for anatoxins, cylindrospermopsins, saxitoxins, microcystins (MCs) and nodularins was carried out. Among all the listed toxins, only one anatoxin and five MCs were detected in the lakes. In particular, the alkaloid anatoxin-a (ATX) was found dominant in lakes Garda, Iseo and Como, and absent in Lake Lugano; the MC-[D-Asp3]RR was found as the most abundant MC in all four lakes. Four other less abundant MCs were also found. The two major toxins are produced by two different cyanobacteria, Tychonema bourrellyi (J.W.G. Lund) Anagnostidis & Komárek and Planktothrix rubescens (De Candolle ex Gomont) Anagnostidis & Komárek, which share however a number of ecological traits. Peaks of these toxins occurred in warmer months (typically between May and September) in the thermocline layer (around 20 m, in the considered lakes). In summer 2016, the highest concentrations of ATX and total MCs were registered in Lake Iseo (1100 and 430 ng L–1, respectively), while in the other lakes values were approximately twice lower. In the lakes where it was present, ATX peak levels were much higher than MCs, thus highlighting the necessity of including ATX in the procedures of risk assessment. The importance of ATX is expected to further grow in the future with respect to MCs, as demonstrated by the long-term trend analysis carried out in Lake Garda that showed a clear decline for MCs from 2009 till 2016 and a relative constancy of ATX. No n-c om me rci al us on ly L. Cerasino and N. Salmaso 12 rubescens (De Candolle ex Gomont) Anagnostidis & Komárek (MCs producer) was observed, which was partially replaced by Tychonema bourrellyi (J.W.G.Lund) Anagnostidis & Komárek (ATXs producer). The two cited toxic species are part of the cyanobacterial populations of DSL, which also comprise Microcystis aeruginosa (Kützing) Kützing, Aphanizomenon flos-aquae Ralfs ex Bornet & Flahault, and Dolichospermum lemmermannii (Richter) P.Wacklin, L.Hoffmann & J.Komárek (Cerasino et al., 2017; Salma
蓝藻毒素是全球关注的淡水问题，富营养化和气候变化可能会产生协同效应，加剧这一问题。深亚高山湖泊是位于阿尔卑斯山脉边界的一组具有巨大经济和自然重要性的湖泊。在意大利和瑞士阿尔卑斯山的南部边界，最大的水体包括加尔达湖、伊塞奥湖、科莫湖、卢加诺湖和马焦雷湖（深亚高山湖泊，DSL）。随着富营养化（在20世纪60年代和70年代）和再贫营养化（从20世纪90年代开始），这些湖泊一直在经历变暖和水柱稳定性的提高。这些变化对浮游植物（包括蓝藻）群落产生了强烈影响。研究了四个DSL（加尔达湖、伊塞奥湖、科莫湖和卢加诺湖），目的是比较它们的毒性潜力。对其中一个（加尔达湖）进行了为期8年的调查，以便进行长期趋势分析。每月通过靶向LC-MS/MS进行毒素分析。对锐钛矿毒素、柱状菌素、沙蜂毒素、微囊藻毒素和结节菌素进行了筛选。在所有列出的毒素中，仅在湖泊中检测到一种锐钛矿毒素和五种MC。特别是生物碱类毒素-a（ATX）在加尔达湖、伊塞奥湖和科莫湖占优势，在卢加诺湖不存在；MC-[D-Asp3]RR是四个湖泊中含量最高的MC。还发现了另外四种含量较低的MC。这两种主要毒素是由两种不同的蓝细菌产生的，Tyconema bourrelli（J.W.G.Lund）Anagnostidis&Komárek和Planktothrix rubscens（De Candolle ex Gomont）Anagnosticis&Komārek，它们有许多共同的生态特征。这些毒素的峰值出现在温暖的月份（通常在5月至9月之间），位于温跃层（在所考虑的湖泊中，约20米）。2016年夏天，Iseo湖的ATX和总MC浓度最高（分别为1100和430 ng L–1），而其他湖泊的值约低两倍。在存在ATX的湖泊中，ATX峰值水平远高于MC，因此强调了将ATX纳入风险评估程序的必要性。在加尔达湖进行的长期趋势分析表明，ATX在未来对MC的重要性预计将进一步增加，该分析显示，从2009年到2016年，MC明显下降，ATX相对稳定。没有观察到L.Cerasino和n.Salmaso 12冬凌草（De Candolle ex Gomont）Anagnostidis&Komárek（MC生产商）的n-c om me rci al us，它被Tyconema bourrelli（J.W.G.Lund）Anagnosticdis&Komárek（ATX生产商）部分取代。被引用的两种有毒物种是DSL蓝藻种群的一部分，其还包括铜绿微囊藻（Kützing）Kütsing、Aphanizomenon flos aquae Ralfs ex Bornet&Flahault和Dolichspermum lemmermanni（Richter）P.Wacklin、L.Hoffmann和J.Komárek（Cerasino等人，2017；萨尔马索，2019；萨尔马苏等人，2018a）。对从DSL中分离的菌株进行的分析（Cerasino等人，2017）表明，铜绿假单胞菌和冬凌草可以产生MC，T.bourrellii anatoxin-a（ATX），而a.flos aquae和D.lemmermanini则无毒。一项连续的研究（Capelli等人，2017）也表明，在DSL中分离的莱默曼尼D.lemmermanii菌株缺乏毒性是由于缺乏MC和ATX编码基因。2009年进行了一项实地研究，以评估DSL中蓝藻种群的毒性潜力（Cerasino和Salmaso，2012）；研究表明，i）MC存在于所有DSL中，以去甲基化变体为主；以及ii）ATX存在于五个湖泊中的四个，卢加诺湖除外。此外，在研究中，根据不同的湖泊特征来解释湖泊之间毒素浓度的差异；更具体地说，MCs水平与营养物质浓度呈正相关，而ATX水平更依赖于水温，因此表明富营养化和气候变化是以不同方式形成蓝藻多样性的因素。气候因素最近也被报道为欧洲蓝毒素分布的主要驱动因素（Mantzouki等人，2018b）。自2009年以来，对加尔达湖的蓝藻毒素进行了定期测量，从而可以跟踪该湖的潜在毒性变化。如果加尔达湖和其他DSL的寡养作用肯定对蓝藻增殖有保护作用，那么气候变化的影响就更难评估，因为它们可以通过多种方式发挥作用，例如提高水温和水柱稳定性，增加二氧化碳，以及改变水文（Callieri等人，2014；Pareeth等人，2017；Visser等人，2016）。
{"title":"Co-occurrence of anatoxin-a and microcystins in Lake Garda and other deep subalpine lakes","authors":"L. Cerasino, N. Salmaso","doi":"10.4081/aiol.2020.8677","DOIUrl":"https://doi.org/10.4081/aiol.2020.8677","url":null,"abstract":"Cyanotoxins are a global concern in freshwaters and eutrophication and climate changes can have synergistic effects in exacerbating the problem. The deep perialpine lakes are a group of lakes of huge economic and naturalistic importance located at the border of the Alps. At the southern border of the Italian and Swiss Alps, the largest waterbodies include the lakes Garda, Iseo, Como, Lugano and Maggiore (Deep Subalpine Lakes, DSL). Together with eutrophication (during the 1960s and 1970s) and re-oligotrophication (from the 1990s onward) these lakes have been experiencing warming and increase of the water column stability. These changes had a strong impact on the phytoplankton (including cyanobacteria) community. Four DSL (lakes Garda, Iseo, Como and Lugano) have been studied with the aim of comparing their toxic potential. For one of them (Lake Garda) an 8 years survey was conducted, allowing a long-term trend analysis. Toxin analysis was conducted on a monthly basis by targeted LC-MS/MS. A screening for anatoxins, cylindrospermopsins, saxitoxins, microcystins (MCs) and nodularins was carried out. Among all the listed toxins, only one anatoxin and five MCs were detected in the lakes. In particular, the alkaloid anatoxin-a (ATX) was found dominant in lakes Garda, Iseo and Como, and absent in Lake Lugano; the MC-[D-Asp3]RR was found as the most abundant MC in all four lakes. Four other less abundant MCs were also found. The two major toxins are produced by two different cyanobacteria, Tychonema bourrellyi (J.W.G. Lund) Anagnostidis & Komárek and Planktothrix rubescens (De Candolle ex Gomont) Anagnostidis & Komárek, which share however a number of ecological traits. Peaks of these toxins occurred in warmer months (typically between May and September) in the thermocline layer (around 20 m, in the considered lakes). In summer 2016, the highest concentrations of ATX and total MCs were registered in Lake Iseo (1100 and 430 ng L–1, respectively), while in the other lakes values were approximately twice lower. In the lakes where it was present, ATX peak levels were much higher than MCs, thus highlighting the necessity of including ATX in the procedures of risk assessment. The importance of ATX is expected to further grow in the future with respect to MCs, as demonstrated by the long-term trend analysis carried out in Lake Garda that showed a clear decline for MCs from 2009 till 2016 and a relative constancy of ATX. No n-c om me rci al us on ly L. Cerasino and N. Salmaso 12 rubescens (De Candolle ex Gomont) Anagnostidis & Komárek (MCs producer) was observed, which was partially replaced by Tychonema bourrellyi (J.W.G.Lund) Anagnostidis & Komárek (ATXs producer). The two cited toxic species are part of the cyanobacterial populations of DSL, which also comprise Microcystis aeruginosa (Kützing) Kützing, Aphanizomenon flos-aquae Ralfs ex Bornet & Flahault, and Dolichospermum lemmermannii (Richter) P.Wacklin, L.Hoffmann & J.Komárek (Cerasino et al., 2017; Salma","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/aiol.2020.8677","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47187378","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}
P. Javid, Hassan Zadabbas Shahabadi, Homeyra Amirkhani, Narges Amrollahi, M. S. Ranjbar
Due to specific environmental and ecological conditions, mangrove forests are known as marine transitional zones between sea and land, and, as such, they host organisms with high ecological plasticity. The mangrove forests of Qeshm Island (Iran) are relatively pristine habitats and represent an ideal target for investigating patterns of either aquatic or benthic biodiversity. To provide insights on microbial diversity in this area, nineteen halophilic and halotolerant bacteria were isolated from the sediments in 2017 during low tide. The extracted bacterial strains were studied morphologically by streaking, initial observation of colonies and bacterial staining, and characterized using a battery of biochemical tests including KOH, MR, VP, urease, TSI, S/I/M, Mac, LIA, ODC, ADH, oxidase, catalase, and tryptophan deaminase. The optimum growth of halophilic bacteria was observed in salt concentrations from 5 to 20% NaCl, whereas the extreme halophilic Gram-positive strain grew in salt concentration of up to 30% NaCl. Molecular analyses were also carried out on four halophilic strains and one extreme halophilic gram-positive bacteria. Phylogenetic taxonomy analysis, after 16S rDNA gene Sanger sequencing, revealed that the halophilic bacteria were closely related to the strain types of the genus Bacillus including Bacillus licheniformis, Bacillus velezensis, Bacillus Paralicheniformis and Bacillus sp. with 99% bootstrap value. The extreme halophilic strain was associated to strains of Planococcus plakortidis with 100% bootstrap value. No n-c om me rci al us e nly
{"title":"Isolation and identification of halophilic and halotolerant bacteria from the sediments of the Qeshm Island mangrove forest","authors":"P. Javid, Hassan Zadabbas Shahabadi, Homeyra Amirkhani, Narges Amrollahi, M. S. Ranjbar","doi":"10.4081/aiol.2020.8743","DOIUrl":"https://doi.org/10.4081/aiol.2020.8743","url":null,"abstract":"Due to specific environmental and ecological conditions, mangrove forests are known as marine transitional zones between sea and land, and, as such, they host organisms with high ecological plasticity. The mangrove forests of Qeshm Island (Iran) are relatively pristine habitats and represent an ideal target for investigating patterns of either aquatic or benthic biodiversity. To provide insights on microbial diversity in this area, nineteen halophilic and halotolerant bacteria were isolated from the sediments in 2017 during low tide. The extracted bacterial strains were studied morphologically by streaking, initial observation of colonies and bacterial staining, and characterized using a battery of biochemical tests including KOH, MR, VP, urease, TSI, S/I/M, Mac, LIA, ODC, ADH, oxidase, catalase, and tryptophan deaminase. The optimum growth of halophilic bacteria was observed in salt concentrations from 5 to 20% NaCl, whereas the extreme halophilic Gram-positive strain grew in salt concentration of up to 30% NaCl. Molecular analyses were also carried out on four halophilic strains and one extreme halophilic gram-positive bacteria. Phylogenetic taxonomy analysis, after 16S rDNA gene Sanger sequencing, revealed that the halophilic bacteria were closely related to the strain types of the genus Bacillus including Bacillus licheniformis, Bacillus velezensis, Bacillus Paralicheniformis and Bacillus sp. with 99% bootstrap value. The extreme halophilic strain was associated to strains of Planococcus plakortidis with 100% bootstrap value. No n-c om me rci al us e nly","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/aiol.2020.8743","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47747838","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}
Aquatic ecosystems face several major challenges from the introduction and invasion of species, to overfishing. In order to better manage these situations, we need predictive models, where diverse scenarios can be simulated and tested. One key challenge to address is how to quantify the relationships between single-species disturbances and their multispecies effects. Mapping the spread of direct and indirect effects in food webs helps to link species to communities. Since food webs are complex networks of interactions, it is typically not easy to make predictions, so modelling and simulation may help to reveal general patterns. In food web simulations, one can quantify the effects of local perturbations on other species, i.e., community response. This may provide information about the relative importance of individual species and it is also useful to assess the vulnerability of the whole community to local changes. However, community response can be measured in several ways and various response functions give different results. In order to better understand their similarities and differences, we present a comparative study on a reasonable set of community response functions in food web simulations. These results contribute to build more predictive, multi-species models for systems-based conservation and management. No n-c om me rci al us e o nly Aquatic food web models 95 simulation process, none of them extinct even in the course of perturbations. We modelled the dynamic behaviour of the networks in the same way as we did in Móréh et al. (2018). The dynamics can be described as follows:
{"title":"Comparing community response indices in aquatic food web models","authors":"Ágnes Móréh, F. Jordán","doi":"10.4081/aiol.2019.8621","DOIUrl":"https://doi.org/10.4081/aiol.2019.8621","url":null,"abstract":"Aquatic ecosystems face several major challenges from the introduction and invasion of species, to overfishing. In order to better manage these situations, we need predictive models, where diverse scenarios can be simulated and tested. One key challenge to address is how to quantify the relationships between single-species disturbances and their multispecies effects. Mapping the spread of direct and indirect effects in food webs helps to link species to communities. Since food webs are complex networks of interactions, it is typically not easy to make predictions, so modelling and simulation may help to reveal general patterns. In food web simulations, one can quantify the effects of local perturbations on other species, i.e., community response. This may provide information about the relative importance of individual species and it is also useful to assess the vulnerability of the whole community to local changes. However, community response can be measured in several ways and various response functions give different results. In order to better understand their similarities and differences, we present a comparative study on a reasonable set of community response functions in food web simulations. These results contribute to build more predictive, multi-species models for systems-based conservation and management. No n-c om me rci al us e o nly Aquatic food web models 95 simulation process, none of them extinct even in the course of perturbations. We modelled the dynamic behaviour of the networks in the same way as we did in Móréh et al. (2018). The dynamics can be described as follows:","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/aiol.2019.8621","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43082268","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}
B. Leoni, Morena Spreafico, M. Patelli, V. Soler, L. Garibaldi, V. Nava
We review the state of the art of limnological studies in Lake Iseo and provide updated data concerning long-term investigations (from 1993 to 2018) carried out on chemical and physical parameters (e.g., oxygen, phosphorus, silicon). Changes observed in Lake Iseo were compared with those reported in other Deep South alpine Lakes (DSLs) to highlight analogies and differences of long-term chemical, physical, and biological patterns. Until the 1960s, Lake Iseo and other DSLs were oligotrophic. The increase of anthropogenic pressure and global warming has led to a progressive and unrecovered process of eutrophication. Moreover, the decrease in frequency of full mixing episodes has induced a state of temporary meromixis. Other changes have been identified over the last two decades, especially concerning the phytoplankton and zooplankton communities, and new emerging chemical pollutants were detected. Given the important ecological and socioeconomic role of Lake Iseo, long-term investigations are of paramount importance to understand the response of the lake ecosystem to climatic and anthropogenic stressors. These two factors can also act coupled with new combined and synergic effects. No n-c om me rci al us e o nly
{"title":"Long-term studies for evaluating the impacts of natural and anthropic stressors on limnological features and the ecosystem quality of Lake Iseo","authors":"B. Leoni, Morena Spreafico, M. Patelli, V. Soler, L. Garibaldi, V. Nava","doi":"10.4081/aiol.2019.8622","DOIUrl":"https://doi.org/10.4081/aiol.2019.8622","url":null,"abstract":"We review the state of the art of limnological studies in Lake Iseo and provide updated data concerning long-term investigations (from 1993 to 2018) carried out on chemical and physical parameters (e.g., oxygen, phosphorus, silicon). Changes observed in Lake Iseo were compared with those reported in other Deep South alpine Lakes (DSLs) to highlight analogies and differences of long-term chemical, physical, and biological patterns. Until the 1960s, Lake Iseo and other DSLs were oligotrophic. The increase of anthropogenic pressure and global warming has led to a progressive and unrecovered process of eutrophication. Moreover, the decrease in frequency of full mixing episodes has induced a state of temporary meromixis. Other changes have been identified over the last two decades, especially concerning the phytoplankton and zooplankton communities, and new emerging chemical pollutants were detected. Given the important ecological and socioeconomic role of Lake Iseo, long-term investigations are of paramount importance to understand the response of the lake ecosystem to climatic and anthropogenic stressors. These two factors can also act coupled with new combined and synergic effects. No n-c om me rci al us e o nly","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/aiol.2019.8622","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45409255","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. A. Andong, N. Ezenwaji, Temitope Dadewura Melefa, Funmilayo Faith Hinmikaiye, Obiechina Vitus Nnadi, O. Oluwafemi
Constant assessment of physical and chemical parameters in freshwater ecosystems is largely recommended. This is even more important when water resources, e.g. lakes in most countries, serve as a source of water for domestic and commercial purposes, and /or when freshwater ecosystems represent a refuge for most aquatic organisms. In this paper, we investigated the physical and chemical properties of water resources at three sampling stations of Lake Oguta, comparing the weekly values (June-July 2018) with the water quality standard established by the Nigerian Federal Ministry of Water Resources (FMWR). The parameters analysed included water temperature, pH, dissolved oxygen (DO), chemical and biological oxygen demand (COD, BOD), potassium, magnesium, sodium, calcium, phosphate, nitrate, chloride and sulphate. Most of the cations (calcium, magnesium and sodium), anions (phosphate, nitrate, chloride and sulphate), as well as water temperature, BOD and DO were below the quality standard limits. The basic chemistry and temporal variations may have been caused mostly by natural factors such as geology, topography, meteorology, hydrology, water levels and biological activity. Being in line with the recommended standard levels, the nutrient concentrations, pH and hardness in the current study may indicate favourable conditions for the life of aquatic organisms and contemporary co-existence with the human exploitation for drinking purposes. Nevertheless, to assure a safely and conscious exploitation of this water resource, we recommend continuity in the monitoring studies. To assure an accurate evaluation of the physical and chemical parameters, future studies should include a larger sample size and extended study periods (including other seasons).
{"title":"Assessment of the physico-chemical properties of Oguta Lake compared to the established values of the Federal Ministry of Environment, Nigeria","authors":"F. A. Andong, N. Ezenwaji, Temitope Dadewura Melefa, Funmilayo Faith Hinmikaiye, Obiechina Vitus Nnadi, O. Oluwafemi","doi":"10.4081/aiol.2019.8522","DOIUrl":"https://doi.org/10.4081/aiol.2019.8522","url":null,"abstract":"Constant assessment of physical and chemical parameters in freshwater ecosystems is largely recommended. This is even more important when water resources, e.g. lakes in most countries, serve as a source of water for domestic and commercial purposes, and /or when freshwater ecosystems represent a refuge for most aquatic organisms. In this paper, we investigated the physical and chemical properties of water resources at three sampling stations of Lake Oguta, comparing the weekly values (June-July 2018) with the water quality standard established by the Nigerian Federal Ministry of Water Resources (FMWR). The parameters analysed included water temperature, pH, dissolved oxygen (DO), chemical and biological oxygen demand (COD, BOD), potassium, magnesium, sodium, calcium, phosphate, nitrate, chloride and sulphate. Most of the cations (calcium, magnesium and sodium), anions (phosphate, nitrate, chloride and sulphate), as well as water temperature, BOD and DO were below the quality standard limits. The basic chemistry and temporal variations may have been caused mostly by natural factors such as geology, topography, meteorology, hydrology, water levels and biological activity. Being in line with the recommended standard levels, the nutrient concentrations, pH and hardness in the current study may indicate favourable conditions for the life of aquatic organisms and contemporary co-existence with the human exploitation for drinking purposes. Nevertheless, to assure a safely and conscious exploitation of this water resource, we recommend continuity in the monitoring studies. To assure an accurate evaluation of the physical and chemical parameters, future studies should include a larger sample size and extended study periods (including other seasons).","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/aiol.2019.8522","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43926604","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}
Stefania Peddio, G. Sollai, C. Podda, Giacomo Frau, F. Palmas, A. Sabatini, R. Crnjar, P. Solari
Pheromone-driven sex recognition has been widely documented in crayfish and a great deal of evidence supports the involvement of pheromones in their mating behaviour. This study investigates whether sexual interaction and mating success in the red swamp crayfish Procambarus clarkii are dependent on short-distance chemical communication between sexes, mediated by urine-borne pheromones. We compared the mating behaviour of intact animals that could release urine to chemically communicate in a natural way with that of urine-blocked animal pairs, for which chemical communication was precluded. Our results show that urine-borne pheromones are not critical for the reproductive success of P. clarkii, at least over the short-range distance (<1 m) considered in this study, during which the animals were confined in a restricted tank, facing one each other, and thus able to promptly mate. Under these experimental conditions, a lack of urine release neither precluded the occurrence, nor affected the duration of the different phases of mating behaviour. We conclude that short-distance chemical communication in P. clarkii is not a prerequisite for mating, and suggest that it could be affected by alternative sensory modalities, likely vision and/or acoustic signalling. No n-c om me rci al us e o nly
{"title":"The success in the short-distance communication for mating does not depend on chemical signals in the crustacean decapod Procambarus clarkii (Girard, 1852)","authors":"Stefania Peddio, G. Sollai, C. Podda, Giacomo Frau, F. Palmas, A. Sabatini, R. Crnjar, P. Solari","doi":"10.4081/aiol.2019.8617","DOIUrl":"https://doi.org/10.4081/aiol.2019.8617","url":null,"abstract":"Pheromone-driven sex recognition has been widely documented in crayfish and a great deal of evidence supports the involvement of pheromones in their mating behaviour. This study investigates whether sexual interaction and mating success in the red swamp crayfish Procambarus clarkii are dependent on short-distance chemical communication between sexes, mediated by urine-borne pheromones. We compared the mating behaviour of intact animals that could release urine to chemically communicate in a natural way with that of urine-blocked animal pairs, for which chemical communication was precluded. Our results show that urine-borne pheromones are not critical for the reproductive success of P. clarkii, at least over the short-range distance (<1 m) considered in this study, during which the animals were confined in a restricted tank, facing one each other, and thus able to promptly mate. Under these experimental conditions, a lack of urine release neither precluded the occurrence, nor affected the duration of the different phases of mating behaviour. We conclude that short-distance chemical communication in P. clarkii is not a prerequisite for mating, and suggest that it could be affected by alternative sensory modalities, likely vision and/or acoustic signalling. No n-c om me rci al us e o nly","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/aiol.2019.8617","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46293007","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}
Lago Piccolo and Lago Grande di Monticchio lie in the collapsed caldera of the volcanic structure of Mt. Vulture (Basilicata, Italy). In over two centuries, a number of studies on their water and on their submerged and riparian vegetation, were carried out, demonstrating an interesting biodiversity. The entire lake area, which is impacted by strong tourist pressure, is part of the "Monte Vulture" Special Area of Conservation (SAC IT9210210). The aim of this paper is to review the literature studies on these lakes, in order to identify the more suitable limnological parameters to infer the history of the trophic status of the two lakes. For this reason, we assess the current ecological status of the two lakes on the basis of physical, chemical and biological analyses deriving from two recent surveys carried out in 2005-2007 and in 2015, and compare these data with sparse, but relevant, historical records, in order to assess how human impacts affected both these lakes and to understand the differences in their present trophic status. Because of its peculiar water chemistry, Lago Piccolo is resulted in good and stable ecological conditions. On the contrary, water transparency of Lago Grande came out very low in summer, while total phosphorus and nitrogen concentration are proved high, leading to the persistence of critical environmental conditions in this lake, with high algal biomass and durable algal blooms in late summer, dominated by cyanobacteria. Finally, in absence of standard protocols and seasonal samplings, the macrophyte maximum growing depth should be considered the more reliable indicator of trophic status among those available for these specific lakes, being relatively independent from sampling methods and seasonal pattern.
Piccolo湖和Grande di Monticchio湖位于意大利巴西利卡塔(Basilicata)秃鹫山(Mt. Vulture)火山结构的崩塌火山口。两个多世纪以来，人们对这里的水、水下植被和河岸植被进行了大量研究，展示了这里有趣的生物多样性。整个湖区受到强烈旅游压力的影响，是“秃鹫山”特别保护区(SAC IT9210210)的一部分。本文旨在对这两个湖泊的研究文献进行综述，以确定更合适的湖泊参数来推断这两个湖泊的营养状况的历史。为此，我们基于2005-2007年和2015年两次近期调查的物理、化学和生物分析，对这两个湖泊的当前生态状况进行了评估，并将这些数据与稀疏但相关的历史记录进行了比较，以评估人类活动对这两个湖泊的影响，并了解它们目前营养状况的差异。由于其独特的水化学，造就了短歌湖良好而稳定的生态条件。相反，Lago Grande湖水在夏季透明度很低，而总磷和总氮浓度较高，导致该湖的临界环境条件持续存在，藻类生物量高，夏末藻华持续存在，以蓝藻为主。最后，在缺乏标准方案和季节性采样的情况下，相对独立于采样方法和季节模式的大型植物最大生长深度应被认为是这些特定湖泊中更可靠的营养状况指标。
{"title":"The contrasting evolution of twin volcanic lakes (Monticchio, Mt. Vulture, Italy) inferred from literature records","authors":"R. Spicciarelli, A. Marchetto","doi":"10.4081/AIOL.2019.7949","DOIUrl":"https://doi.org/10.4081/AIOL.2019.7949","url":null,"abstract":"Lago Piccolo and Lago Grande di Monticchio lie in the collapsed caldera of the volcanic structure of Mt. Vulture (Basilicata, Italy). In over two centuries, a number of studies on their water and on their submerged and riparian vegetation, were carried out, demonstrating an interesting biodiversity. The entire lake area, which is impacted by strong tourist pressure, is part of the \"Monte Vulture\" Special Area of Conservation (SAC IT9210210). The aim of this paper is to review the literature studies on these lakes, in order to identify the more suitable limnological parameters to infer the history of the trophic status of the two lakes. For this reason, we assess the current ecological status of the two lakes on the basis of physical, chemical and biological analyses deriving from two recent surveys carried out in 2005-2007 and in 2015, and compare these data with sparse, but relevant, historical records, in order to assess how human impacts affected both these lakes and to understand the differences in their present trophic status. Because of its peculiar water chemistry, Lago Piccolo is resulted in good and stable ecological conditions. On the contrary, water transparency of Lago Grande came out very low in summer, while total phosphorus and nitrogen concentration are proved high, leading to the persistence of critical environmental conditions in this lake, with high algal biomass and durable algal blooms in late summer, dominated by cyanobacteria. Finally, in absence of standard protocols and seasonal samplings, the macrophyte maximum growing depth should be considered the more reliable indicator of trophic status among those available for these specific lakes, being relatively independent from sampling methods and seasonal pattern.","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/AIOL.2019.7949","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44612136","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}
While variations in sedimentary organic matter (OM) quantity, biochemical composition and nutritional quality as well as in meiofaunal abundance and assemblage composition at the macro- and mesoscale are relatively well known, information about variations at the microscale is much scarcer. To shed some light on this issue, we tested the null hypothesis by which abundance and composition of the meiofaunal assemblages, and the quantity, biochemical composition and nutritional quality of sedimentary organic matter in coastal shallow environments do not vary within a frame of 1 m2. No significant variation within the frame emerged for OM quantity, nutritional quality, biochemical composition and the abundance of meiofaunal assemblages. On the other hand, the composition of meiofaunal assemblages varied significantly within the frame and exhibited a clear segregation of assemblages farther to the shore, as a likely result of local micro-hydrodynamic conditions. Spatial autocorrelation analysis revealed that lipid and protein sedimentary contents had a random distribution, whereas carbohydrate and biopolymeric C contents and meiofaunal total abundance were characterized by a patchy distribution, with discrete peaks within the sub-frame squares (ca. 0.1 m2). Phytopigments showed a spatial positive autocorrelation distribution, following the micro-hydrodynamic pattern, with patches larger than the sub-frame square, but smaller than the entire one (1 m2). Overall, our results suggest that, within 1 m2 of subtidal sandy sediments, three replicates could be sufficient to assess correctly OM attributes and the abundance of meiofauna, but could be possibly inadequate for assessing meiofaunal assemblages’ composition at a finer scale (<1 m2).
{"title":"Small-scale distribution of metazoan meiofauna and sedimentary organic matter in subtidal sandy sediments (Mediterranean Sea)","authors":"D. Moccia, A. Cau, M. Meloni, A. Pusceddu","doi":"10.4081/AIOL.2019.8169","DOIUrl":"https://doi.org/10.4081/AIOL.2019.8169","url":null,"abstract":"While variations in sedimentary organic matter (OM) quantity, biochemical composition and nutritional quality as well as in meiofaunal abundance and assemblage composition at the macro- and mesoscale are relatively well known, information about variations at the microscale is much scarcer. To shed some light on this issue, we tested the null hypothesis by which abundance and composition of the meiofaunal assemblages, and the quantity, biochemical composition and nutritional quality of sedimentary organic matter in coastal shallow environments do not vary within a frame of 1 m2. No significant variation within the frame emerged for OM quantity, nutritional quality, biochemical composition and the abundance of meiofaunal assemblages. On the other hand, the composition of meiofaunal assemblages varied significantly within the frame and exhibited a clear segregation of assemblages farther to the shore, as a likely result of local micro-hydrodynamic conditions. Spatial autocorrelation analysis revealed that lipid and protein sedimentary contents had a random distribution, whereas carbohydrate and biopolymeric C contents and meiofaunal total abundance were characterized by a patchy distribution, with discrete peaks within the sub-frame squares (ca. 0.1 m2). Phytopigments showed a spatial positive autocorrelation distribution, following the micro-hydrodynamic pattern, with patches larger than the sub-frame square, but smaller than the entire one (1 m2). Overall, our results suggest that, within 1 m2 of subtidal sandy sediments, three replicates could be sufficient to assess correctly OM attributes and the abundance of meiofauna, but could be possibly inadequate for assessing meiofaunal assemblages’ composition at a finer scale (<1 m2).","PeriodicalId":37306,"journal":{"name":"Advances in Oceanography and Limnology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4081/AIOL.2019.8169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41638488","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：