Advances in Oceanography and Limnology 2019-11-11T17:50:08+01:00 Nadia Moscato Open Journal Systems <p><strong>Advances in Oceanography and Limnology</strong>&nbsp;(<em>AIOL Journal</em>) is the official publication of the <a href="" target="_blank" rel="noopener">Italian Association of Limnology and Oceanology</a> (A.I.O.L.).</p> <p>The <em>AIOL Journal </em>publishes original research articles and reviews on different topics and novel discoveries in the fields of limnology and oceanography. Papers may deal with different or single physical, chemical and biological aspects, including biomolecules, populations and communities, ecosystem functioning and interactions between global change and ecosystems. Environmental monitoring and studies of regional importance will be considered only if they contribute to the general advance of aquatic sciences. Multidisciplinary articles linking different scientific disciplines (e.g., community ecology and metabolomic/toxicology, ecology and phylogenetic, water quality and economy…) are equally considered. Particularly welcomed are studies focusing on marine and freshwater ecosystems.</p> <p>Two regular issues of the <strong>Advances in Oceanography and Limnology</strong> are published each year. In addition, Special Issues and Proceedings that focus on topics that are timely and of interest to a significant number of aquatic scientists are published. From 2010 to 2014, previous issues of the <em>AIOL Journal</em> have been published by&nbsp;<a href="">T&amp;F</a>.</p> <p>This journal does not apply charge for publication to Authors as it is supported by institutional funds.</p> Sediment classification in a Brazilian reservoir: Pros and cons of parametric low frequencies 2019-11-11T17:50:08+01:00 Klajdi Sotiri Stephan Hilgert Stephan Fuchs <p>Sediment is the main factor that limits the reservoir lifetime. Therefore, sediment classification is an essential tool for planning and operating reservoir management measures. There has been important development in the hydroacoustic classification of lakebed, especially with linear systems. The main restrictions while using linear hydroacoustic systems for lakebed classification are the shallow penetration in high-frequency applications or the low vertical and horizontal resolution when using low frequencies. With the new developments in the area of echo sounders, parametric systems can achieve high penetration while preserving the high vertical and lateral resolution. To investigate the performance of parametric systems, a new lakebed classification approach was implemented by using a SES2000 Compact. The area studied was the Passauna reservoir in Parana State, Brazil. We used the first echo division method for processing the acoustic data combined with sediment core and grab sampling. The two physical parameters investigated, were the share of the finest fraction (&lt;63 µm) and wet bulk density (WBD). The results showed a high correlation between the primary frequency of 100 kHz (166 µs pulse length) and the physical parameters. Additionally, a significant correlation was observed with the acoustic parameters at 10 kHz frequency. The best correlating acoustic parameter was Attack/Decay (E1´/E1). The gas presence was found to be an important factor determining the penetration depth of the parametric system and the performance of the classification. The advantages of parametric systems, such small directivity and layering effect, represent the major restrictions in sediment classification applications.</p> 2019-05-27T00:00:00+02:00 ##submission.copyrightStatement## Variations of indicative dates of ice regime on Lake Onego based on ground air temperature 2019-11-11T17:50:06+01:00 Vyacheslav N. Baklagin <p class="Abstract" style="line-height: normal;"><span lang="EN-US" style="color: black;">The paper shows the changes in the dates (complete freeze-up, ±5 days/°C and complete ice clearance, ±3 days/°C) of the ice regime in Lake Onego depending on changes in average air temperature within the preceding two-month periods (autumn and spring). The regression equations for their calculation based on previous three- and four-month periods according to the 2000-2018 data are also provided. Indicative dates of ice regime based on accumulated air temperatures within the ice period of Lake Onego were also established (early formation of ice phenomena, complete freeze-up phase, beginning of the break-up phase and complete ice clearance). Together with the data on expected air temperature above the lake’s surface, these dependencies enable us to predict the indicative dates of the ice regime.</span></p> 2019-06-25T00:00:00+02:00 ##submission.copyrightStatement## Modulation of hydrolytic profiles of cell-bound and cell-free exoenzymes in Antarctic marine bacterial isolates 2019-11-11T17:50:05+01:00 Vincenzo Manna Paola Del Negro Mauro Celussi <p>Microbial degradation of high molecular weight organic matter in the marine environment is dependent on the synthesis and activity of hydrolytic exoenzymes. These can be found both associated to the cell (<em>i.e</em>., attached to cell-wall or in the periplasmic space) and cell-free, dissolved in the surrounding waters. Recent evidences suggest that exoenzymes location is linked to different foraging strategies. ‘Selfish’ bacteria use cell-bound enzymes to obtain large oligomers which are then further degraded in the confined periplasmic space, whereas cell-free enzymes are thought to be advantageous for particle-attached prokaryotes, consequently ‘sharing’ the hydrolysis product with other members of the degrading consortium. We examined whether different bacterial isolates exhibit different exoenzymatic activity profiles when exposed to different growth condition. Seven bacterial strains, isolated from the Ross Sea, were screened for the production of β-glucosidase, alkaline-phosphatase, lipase, chitinase and leucine aminopeptidase, assaying the hydrolysis rates of both cell-bound and cell-free exoenzymatic fractions. Furthermore, to test whether bacteria growing on particles are more prone to produce cell-free exoenzymes, we set up a controlled experiment, amending one of the bacterial isolates with phytodetritus, in order to promote the colonization of aggregates. Cell specific hydrolytic rates were highly variable and different isolates expressed different dominant hydrolytic activities. These results demonstrate a specialization for different substrates in different bacteria, further suggesting that some of the tested isolates may have an intrinsic potential to copiously produce cell-free exoenzymes. Moreover, our results suggest that this specialization is not strictly genetically determined but varies according to growth conditions. The experiment performed with phytodetrital particles highlighted an increasing contribution of the dissolved exoenzymatic activity in samples bearing aggregates and associated bacteria. Also, the tested isolate further modulated its hydrolytic machinery, expressing a different enzymatic profile when exposed to phytodetrital particles. The continuation of these experimental activities, testing the response of different bacterial isolates to different substrates, will help to determine the conditions under which different hydrolysis patterns develop, deepening the current knowledge on the organic matter cycling in the ocean.</p> 2019-06-25T14:48:27+02:00 ##submission.copyrightStatement## The contrasting evolution of twin volcanic lakes (Monticchio, Mt. Vulture, Italy) inferred from literature records 2019-11-11T17:50:05+01:00 Renato Spicciarelli Aldo Marchetto <p>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.</p> 2019-07-01T00:00:00+02:00 ##submission.copyrightStatement## Small-scale distribution of metazoan meiofauna and sedimentary organic matter in subtidal sandy sediments (Mediterranean Sea) 2019-11-11T17:50:04+01:00 Davide Moccia Alessandro Cau Maria Carmela Meloni Antonio Pusceddu <p>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 m<sup>2</sup>. 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 m<sup>2</sup>). 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 m<sup>2</sup>). Overall, our results suggest that, within 1 m<sup>2 </sup>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 (&lt;1 m<sup>2</sup>).</p> 2019-07-01T12:09:39+02:00 ##submission.copyrightStatement## On the occurrence and distribution of Calanipeda aquaedulcis Kritschagin, 1873 (Copepoda, Calanoida, Pseudodiaptomidae) in Sicily, Italy, with some notes on coexistence and species replacement in calanoid copepods 2019-11-11T17:50:08+01:00 Luca Vecchioni Federico Marrone Luigi Naselli-Flores <p>The only population of the pseudodiaptomid copepod <em>Calanipeda aquaedulcis</em> Kritschagin, 1873 to date reported to occur in Sicily disappeared at the beginning of the XXI century due to deep environmental changes which affected the single site (Lake Biviere di Gela) known for this species on the island. In that site <em>C. aquaedulcis</em> is now replaced by <em>Copidodiaptomus numidicus </em>(Gurney, 1909)<em>, </em>a diaptomid copepod whose distribution has been greatly increasing since the second half of the last century. In the present note, the occurrence of <em>C. aquaedulcis</em> in 12 novel water bodies spread throughout Sicily is reported, and some environmental data on the sites where the species was collected are provided. Moreover, in a few sites <em>C. aquaedulcis</em> was found to co-occur with <em>Copidodiaptomus numidicus</em>. The recorded co-occurrence of these two species and the replacement of <em>C. aquaedulcis</em> with <em>C. numidicus</em> in Lake Biviere di Gela are briefly discussed.</p> 2019-05-27T00:00:00+02:00 ##submission.copyrightStatement## Remembering Alvise Vittori (Riva del Garda 1932 – Trento 2018) 2019-11-11T17:50:07+01:00 Giovanna Flaim Francesca Ciutti <p>Dr. Alvise Vittori was a well-known Italian ichthyologist, limnologist and all-round ecologist.</p> 2019-05-27T00:00:00+02:00 ##submission.copyrightStatement##