scholarly journals Phenology of Anemonia viridis and Exaiptasia diaphana (Cnidaria: Anthozoa) from marine temperate ecosystems

Author(s):  
GIOIA CRISTINA Di CAMILLO ◽  
SILVIA AROSSA ◽  
DANIELA PICA ◽  
BASTARI AZZURRA ◽  
FABRIZIO TORSANI ◽  
...  

Population dynamics in lower metazoans are strongly regulated by environmental factors. The running climate crisis could affect regularity of life strategies; therefore, studying life cycles and reproductive patterns of benthic species may provide key information on effects of environmental changes in temperate seas. The North Adriatic Sea is a peculiar basin due to high food availability and high fluctuations of physical parameters. Here, cnidarians are one of the most abundant taxa and sea anemones are the largest representatives. Aim of this study is to assess the life history and the reproductive biology of two potential species models: the sea anemones: Anemonia viridis and Exaiptasia diaphana. The present research is the first quantitative study on the variations in abundance and reproductive biology of the two species. We reported new insights about abundance fluctuations throughout the year and about the gametogenesis of the two sea anemones. In particular, data on spermatogenesis of A. viridis from the Mediterranean Sea were supplied for the first time. 

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250466
Author(s):  
Fahd Saeed Alakbari ◽  
Mysara Eissa Mohyaldinn ◽  
Mohammed Abdalla Ayoub ◽  
Ali Samer Muhsan ◽  
Ibnelwaleed A. Hussein

Sand management is essential for enhancing the production in oil and gas reservoirs. The critical total drawdown (CTD) is used as a reliable indicator of the onset of sand production; hence, its accurate prediction is very important. There are many published CTD prediction correlations in literature. However, the accuracy of most of these models is questionable. Therefore, further improvement in CTD prediction is needed for more effective and successful sand control. This article presents a robust and accurate fuzzy logic (FL) model for predicting the CTD. Literature on 23 wells of the North Adriatic Sea was used to develop the model. The used data were split into 70% training sets and 30% testing sets. Trend analysis was conducted to verify that the developed model follows the correct physical behavior trends of the input parameters. Some statistical analyses were performed to check the model’s reliability and accuracy as compared to the published correlations. The results demonstrated that the proposed FL model substantially outperforms the current published correlations and shows higher prediction accuracy. These results were verified using the highest correlation coefficient, the lowest average absolute percent relative error (AAPRE), the lowest maximum error (max. AAPRE), the lowest standard deviation (SD), and the lowest root mean square error (RMSE). Results showed that the lowest AAPRE is 8.6%, whereas the highest correlation coefficient is 0.9947. These values of AAPRE (<10%) indicate that the FL model could predicts the CTD more accurately than other published models (>20% AAPRE). Moreover, further analysis indicated the robustness of the FL model, because it follows the trends of all physical parameters affecting the CTD.


2019 ◽  
Vol 62 (2) ◽  
pp. 197-246
Author(s):  
Claudia Finkler ◽  
Kalliopi Baika ◽  
Diamanto Rigakou ◽  
Garyfalia Metallinou ◽  
Peter Fischer ◽  
...  

Ancient Corcyra (modern Kerkyra or Corfu) was an important harbour city and commercial centre since the Archaic period, also due to its geostrategic position on the trade routes between Greece and Italy or Sicily. Corcyra kept its status as one of the prevailing naval powers in the Mediterranean by means of a large naval fleet, needing appropriated harbour basins to be stored and repaired. At least two harbours are documented by historical records and associated archaeological remains, namely the Alkinoos and the Hyllaikos Harbours, both located on either side of a narrow isthmus to the north of the Analipsis Peninsula, where the ancient polis developed. Today, the ancient harbour basins are silted and overbuilt by modern urban infrastructure, concealing their overall extent and topography. The present study aims to reconstruct the complex palaeogeographies of the ancient Alkinoos harbour of Corcyra based on a multi-methodological palaeoenvironmental and geoarchaeological approach. The methods used include sedimentary, geochemical, microfaunal and geophysical investigations that were complemented by archaeological data and results from previous geoarchaeological research. Spatially, the study focusses on the area of the so-called Desylla site west of known Alkinoos Harbour sediments in the midst of the modern city of Corfu. These results were complemented by findings from two geomorphological key sites as well as archaeoseismological traces from the western part of the Analipsis Peninsula. At the Desylla site, we found sedimentary evidence of an Archaic pre-harbour, partly open to the Gulf of Corfu, which was the predecessor of a protected Classical harbour basin. This basin, in use between at least the 4th to 3rd cent. BC and the 1st cent. AD, was delimited to the west by a wall. It represents the central part of the Classical Alkinoos Harbour which was sedimentologically traced, for the first time, from the De- sylla site in the west to the Kokotou site in the east, where monumental shipsheds were unearthed during earlier archaeological excavations. Probably, the harbour zone extended even further to the east, where contemporaneous harbour deposits were found associated with the prominent quay wall at the Pierri and Arion sites. Our results show, that, apart from man-made interventions, Corcyra's palaeogeographical evolution is strongly linked to multiple impacts of extreme wave events in the form of tsunami inundation. At least four events (I–IV) are recorded in the natural geoarchives of the Analipsis Peninsula and its surroundings as well as the northern harbour zone of ancient Corcyra. In particular, these events happened between 5600 and 5200 cal BC (event I), after 3900 cal BC (event II), between the 4 th and 3 rd cent. BC (event III) and between the 3 rd and 6 th cent. AD, most likely at 365 AD (event IV). Ages of all events correlate well with ages of tsunami traces found on Sicily, the Greek mainland and other Ionian Islands. Tsunami events I and II led to massive environmental changes around the Analipsis Peninsula, while event III was associated to strong co-seismic uplift, leading to the abandonment of the harbour site at Pierri. Decreasing water depths by siltation of the Kokotou and Desylla sites, however, were redressed by dredging, giving rise to an extensive Roman re-use of the western part of the Alkinoos Harbour zone. Yet, both harbour sites were hit again by event IV filling the harbour basins by a thick sequence of event deposits.


2013 ◽  
Vol 14 (3) ◽  
pp. 49 ◽  
Author(s):  
Z. DURIS ◽  
A. S. ATES ◽  
H. B. OZALP ◽  
T. KATAGAN

Three anemone-associated decapod crustaceans, two shrimp species, Periclimenes amethysteus and P. aegylios (Caridea: Palaemonidae: Pontoniinae), and the crab Inachus phalangium (Brachyura: Inachidae), all collected from the Dardanelles, are reported for the first time from Turkish coasts. Another inachid crab, Macropodia czernjawskii is also reported for the first time to occur in association with the sea anemone, Anemonia viridis. Periclimenes scriptus was the fifth decapod species recorded associated with sea anemones within the present study, and while this species has already been reported from Turkish waters, this is the first time it is recorded from the Dardanelles (the Turkish Straits System).


1976 ◽  
Vol 3 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Arne Jernelöv ◽  
Rutger Rosenberg

It is conventionally argued that a stable ecosystem, namely one with high species-diversity and high constancy in physical parameters, is less sensitive to additional stress than a system with varying physical parameters and low species-diversity. By this logic, the Baltic would be more susceptible to additional stress, such as that of pollution, than the North Sea.Examples of irreparable damage to some of the most stable ecosystems in the world, such as coral reefs and tropical rain-forests, suggest, on the contrary, that these systems are more vulnerable than low-diversity ecosystems, such as a brackish-water zone in the mouth of a river or a coniferous forest in a temperate region.Studies of stress tolerance in estuaries showed that the species already living under stress, such as that of reduced and changing salinities, were more tolerant to pollution than species in a less fluctuating environment. This adaptability to environmental changes seems to be characteristic of ecosystems with a low degree of individual specialization and high genetic diversity (i.e. a large number of alleles). Following this conclusion, we question the underlying assumptions in the statement that for example the Baltic Sea, which can be regarded as a large estuary, is an area particularly susceptible to stress; purely marine ecosystems are probably more sensitive.Ecosystem stress-tolerance should be made a top priority in ecological research; this is a necessity inter alia for future localization of industries, in order to minimize their effects on the environment.


2021 ◽  
Vol 2 (2) ◽  
pp. 37-48
Author(s):  
Kenanga Sari ◽  
Tri Retnaningsih Soeprobowati

The fast-growing development and industrialization have caused various impacts on nature including heavy metal pollution, especially in the coastal area. Tambakredjo, located in the North Semarang city, is home to a large number of mangrove and animal species. Therefore, water quality is important. This study was conducted to analyze water quality in the coastal area of Tambakredjo based on physical and chemical measurements. Water quality data were collected from different sites. Physical parameters (temperature, pH, DO, EC, TDS, ORP and salinity) and chemical parameters (Total N, Total P, Pb, Cr, Cd) were observed. Multivariate statistical techniques, including Principal Component Analysis (PCA), was applied to evaluate water quality. The results showed first principal component is 76.27%, where the highest conductivity, total dissolved solids and salinity are associated with site 1. Content of Lead 1.289 ppm, Cadmium 0.021 ppm, and Chromium 0.352 ppm exceeds the water quality standard PP. No. 82/2001. It indicated that Site 1 was characterized as the most heavily polluted site because the location received pollutants from rivers and oceans. This study also examined the short-term changes of the mangrove-covered area at the side of Banjir Kanal Timur using historical map satellite images. The results show that mangrove coverage in Tambakredjo near the aquaculture area had decreased from 1,875m2 to 1,401m2. Meanwhile, on the other site, the mangrove planting effort as a restoration program is carried out, especially in the estuary of Banjir Kanal Timur to anticipate more environmental changes.


2020 ◽  
Vol 33 ◽  
pp. 15
Author(s):  
Roi Martínez-Escauriaza ◽  
Claudio Vieira ◽  
Lídia Gouveia ◽  
Nuno Gouveia ◽  
Margarida Hermida

Data obtained from licenses of spearfishers and surveys conducted in 2004 and 2017 allowed for the analysis, for the first time, of the practice of spearfishing in the Madeira archipelago. Only a small percentage of the population practices spearfishing, mostly local young men. Most of them practice the activity with a partner throughout most of the year and along most of the island's coastal areas, although preferentially along the North and Southeast coast. Results show how, in recent years, despite the population of spearfishers decreasing, the abundance in the annual catch potentially increased, probably due to the higher investment of time in this activity. It has been observed that many fishers complement their catches with manual collecting of invertebrates. Overall, 40 teleost fishes and also 4 crustaceans and 8 molluscs were identified. The most frequently captured fish species were parrotfish and white seabream, while limpets were the most collected invertebrates in both selected periods.


2018 ◽  
Vol 52 (2) ◽  
pp. 455-462 ◽  
Author(s):  
G. Ya. Doroshina ◽  
I. A. Nikolajev

Sphagnum mires on the Greater Caucasus are rare, characterized by the presence of relict plant communities of glacial age and are in a stage of degradation. The study of Sphagnum of Chefandzar and Masota mires is carried out for the first time. Seven species of Sphagnum are recorded. Their distribution and frequency within the North Caucasus are analyzed. Sphagnum contortum, S. platyphyllum, S. russowii, S. squarrosum are recorded for the first time for the study area and for the flora of North Ossetia. The other mosses found in the study area are listed.


2018 ◽  
Vol 52 (2) ◽  
pp. 397-406
Author(s):  
A. B. Ismailov ◽  
G. P. Urbanavichus

The lichens and lichenicolous fungi of high mountainous landscapes of Samurskiy Ridge were studied in altitudinal range 2400–3770 m a. s. l. for the first time and 112 species are recorded. Among them 33 species, 10 genera (Arthrorhaphis, Baeomyces, Calvitimela, Epilichen, Lambiella, Psorinia, Rufoplaca, Sagedia, Sporastatia, Tremolecia) and 4 families (Anamylopsoraceae, Arthrorhaphidaceae, Baeomycetaceae, Hymeneliaceae) are new for Dagestan, six species (Buellia uberior, Carbonea atronivea, Lecanora atrosulphurea, Lecidea fuliginosa, L. swartzioidea, Rhizoplaca subdiscrepans) are reported for the first time for the Greater Caucasus and two species (Acarospora subpruinata and Rhizocarpon postumum) — for the North Caucasus. Most of the new findings were collected from 3500–3770 m a. s. l.


2017 ◽  
Vol 51 ◽  
pp. 71-105 ◽  
Author(s):  
N. A. Davidovich

The absence of a conceptual terminology, sufficiently developed and widely accepted in the Russian literature, significantly hinders progress in the field of reproductive biology of diatoms, restricts communication and debate, prevents training and transfer of knowledge. The present work is an attempt, based on world literature and our own research experience, to summarize, systematize, add, and clarify the existing terms, concepts and definitions related to research which are focused on sex and sexual reproduction in diatoms. A glossary of key terms (more than 200, including synonyms) is provided. Terms refer to diatom reproductive biology, life cycles, fertilization, mating system, gender (including inheritance and determination of sex, as well as inheritance associated with sex). Contradictions between possible interpretations of certain terms are briefly discussed.


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