scholarly journals Identification and interpretation of seismic short-duration events inside the Kolumbo submarine volcano in the Southern Aegean

2021 ◽  
Author(s):  
Florian Schmid ◽  
Jens Karstens ◽  
Paraskevi Nomikou
Keyword(s):  
Short Duration ◽  
Eastern Mediterranean ◽  
Volcanic Hazards ◽  
Azimuth Angle ◽  
Discharge Process ◽  
Crater Floor ◽  
Ocean Bottom Seismometer ◽  
Remotely Operated Vehicle ◽  
Toxic Gases ◽  
Bacterial Mats

<p>Kolumbo represents one of the most hazardous, currently active, volcanoes in the eastern Mediterranean. Its last eruption in 1650 AD was associated with a vast explosion, causing a tsunami of regionally devastating impact. The eruption was also associated with the voluminous and rapid release of toxic gases asphyxiating humans and animals on the nearby Islands. Earthquake records from the recent decades document on-going unrest beneath the volcano. Remotely operated vehicle dives revealed several hydrothermal vent sites and bacterial mats at the crater floor, which are concentrated near the northern crater wall. The vents emit mainly CO<sub>2</sub>, leading to the accumulation of acidic waters in the crater. Accordingly, one of the main volcanic hazards associated with Kolumbo is that rapid overturning of water in the crater may release harmful amounts of toxic gases. Monitoring the hydrothermal processes inside the Kolumbo crater will provide an important contribution to the understanding and evaluation of this and other volcanic hazards.</p><p>In October 2019, we deployed an ocean bottom seismometer and hydrophone (OBS/H) inside the Kolumbo crater. During the four days of passive recording we identified about 100 so-called short duration seismic events, which were only present on the seismometer channels, while generally being absent on the hydrophone channels. The events have durations of less than one second with dominant frequencies between 5 to 30 Hz. Most of the events represent well-polarized seismic phases, which enables us to determine their azimuth angle (with a 180-degree bias) and angle of incidence at the OBS/H. We cross-correlated all polarized seismic waveforms and subsequently used the cross-correlation coefficients for a hierarchical cluster analysis to elaborate whether the events have a random origin or originated from a common origin. Our analysis revealed that the majority of events is associated with two clusters. The azimuth angles of all events in the largest cluster coincide with the azimuth angle between station and the field of hydrothermal vents and bacterial mats inside the crater. This coincidence suggests that the origin of the short duration events is associated with the sub-seafloor migration of fluids or the fluid discharge process at the crater floor. In fact, short-duration events of similar characteristics, recorded by OBS/H, were previously attributed to sub-seafloor fluid migration and the discharge of fluids at the seafloor. Our analyses indicate that seismic monitoring of submarine volcanoes should include the detection and analysis of short duration events, which may act as a novel tool in the characterization of volcanic unrests and volcanogenic geohazard monitoring in general.</p>

scholarly journals Development of an Easy-to-Operate Underwater Raman System for Deep-Sea Cold Seep and Hydrothermal Vent In Situ Detection

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5090
Author(s):  
Qingsheng Liu ◽  
Jinjia Guo ◽  
Wangquan Ye ◽  
Kai Cheng ◽  
Fujun Qi ◽  
...  
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
Methane Hydrate ◽  
Sulfur Cycle ◽  
Cold Seep ◽  
Remotely Operated Vehicle ◽  
Bacterial Mats ◽  
Optical Module ◽  
In Situ Detection

As a powerful in situ detection technique, Raman spectroscopy is becoming a popular underwater investigation method, especially in deep-sea research. In this paper, an easy-to-operate underwater Raman system with a compact design and competitive sensitivity is introduced. All the components, including the optical module and the electronic module, were packaged in an L362 × Φ172 mm titanium capsule with a weight of 20 kg in the air (about 12 kg in water). By optimising the laser coupling mode and focusing lens parameters, a competitive sensitivity was achieved with the detection limit of SO42− being 0.7 mmol/L. The first sea trial was carried out with the aid of a 3000 m grade remotely operated vehicle (ROV) “FCV3000” in October 2018. Over 20,000 spectra were captured from the targets interested, including methane hydrate, clamshell in the area of cold seep, and bacterial mats around a hydrothermal vent, with a maximum depth of 1038 m. A Raman peak at 2592 cm−1 was found in the methane hydrate spectra, which revealed the presence of hydrogen sulfide in the seeping gas. In addition, we also found sulfur in the bacterial mats, confirming the involvement of micro-organisms in the sulfur cycle in the hydrothermal field. It is expected that the system can be developed as a universal deep-sea survey and detection equipment in the near future.

scholarly journals Exploring the submarine Graham Bank in the Sicily Channel

2016 ◽  
Vol 59 (2) ◽  
Author(s):  
Mauro Coltelli ◽  
Danilo Cavallaro ◽  
Giuseppe D’Anna ◽  
Antonino D’Alessandro ◽  
Fausto Grassa ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
Structural Features ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
Remotely Operated Vehicle ◽  
Bathymetric Survey ◽  
Submarine Volcanism ◽  
Historical Times ◽  
Sicily Channel ◽  
Sonar Echoes

<p>In the Sicily Channel, volcanic activity has been concentrated mainly on the Pantelleria and Linosa islands, while minor submarine volcanism took place in the Adventure, Graham and Nameless banks. The volcanic activity spanned mostly during Plio-Pleistocene, however, historical submarine eruptions occurred in 1831 on the Graham Bank and in 1891 offshore Pantelleria Island. On the Graham Bank, 25 miles SW of Sciacca, the 1831 eruption formed the short-lived Ferdinandea Island that represents the only Italian volcano active in historical times currently almost completely unknown and not yet monitored. Moreover, most of the Sicily Channel seismicity is concentrated along a broad NS belt extending from the Graham Bank to Lampedusa Island. In 2012, the Istituto Nazionale di Geofisica e Vulcanologia (INGV) carried out a multidisciplinary oceanographic cruise, named “Ferdinandea 2012”, the preliminary results of which represent the aim of this paper. The cruise goal was the mapping of the morpho-structural features of some submarine volcanic centres located in the northwestern side of the Sicily Channel and the temporary recording of their seismic and degassing activity. During the cruise, three OBS/Hs (ocean bottom seismometer with hydrophone) were deployed near the Graham, Nerita and Terribile submarine banks. During the following 9 months they have recorded several seismo-acoustic signals produced by both tectonic and volcanic sources. A high-resolution bathymetric survey was achieved on the Graham Bank and on the surrounding submarine volcanic centres. A widespread and voluminous gas bubbles emission was observed by both multibeam sonar echoes and a ROV (remotely operated vehicle) along the NW side of the Graham Bank, where gas and seafloor samples were also collected.</p>

scholarly journals Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

2012 ◽  
Vol 9 (12) ◽  
pp. 18131-18173
Author(s):  
N. Lampadariou ◽  
V. Kalogeropoulou ◽  
K. Sevastou ◽  
K. Keklikoglou ◽  
J. Sarrazin
Keyword(s):  
Species Richness ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Nematode Community ◽  
Cold Seep ◽  
Mud Volcanoes ◽  
Mussel Bed ◽  
Remotely Operated Vehicle ◽  
Eastern Mediterranean Sea ◽  
Density And Biomass

Abstract. Mud volcanoes are a special type of cold seeps where life is based on chemoautotrophic processes. They are considered as extreme environments and are characterised by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO cruise (2007) with the Remotely Operated Vehicle (ROV) Victor-6000; Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field) and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Nematodes, the dominant meiofaunal taxon, displayed deeper penetration vertically into the sediment at the seep areas, indicating that biological rather than physicochemical factors are responsible for their vertical distribution. Patterns of nematode diversity varied, displaying both very high or very low species richness and dominance, depending on the habitat studied. The Lamellibrachia periphery and mussel bed of Napoli exhibited the highest species richness while the reduced sediments of Amsterdam yielded a species-poor nematode community, dominated by two successful species; one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that habitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.

scholarly journals Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

2013 ◽  
Vol 10 (8) ◽  
pp. 5381-5398 ◽  
Author(s):  
N. Lampadariou ◽  
V. Kalogeropoulou ◽  
K. Sevastou ◽  
K. Keklikoglou ◽  
J. Sarrazin
Keyword(s):  
Species Richness ◽  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Nematode Community ◽  
Cold Seep ◽  
Cold Seeps ◽  
Mud Volcanoes ◽  
Remotely Operated Vehicle ◽  
Eastern Mediterranean Sea ◽  
Density And Biomass

Abstract. Mud volcanoes are a~special type of cold seeps where life is based on chemoautotrophic processes. They are considered to be extreme environments and are characterized by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO (MEditerranean Deep-sea ECOsystems) cruise (2007) with the remotely operated vehicle (ROV) Victor-6000: Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field); and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Patterns of nematode diversity, the dominant meiofaunal taxon, varied, displaying both very high or very low species richness and dominance, depending on the microhabitat studied. The periphery of the Lamellibrachia and bivalve shell microhabitats of Napoli exhibited the highest species richness, while the reduced sediments of Amsterdam yielded a species-poor nematode community dominated by two successful species, one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that microhabitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.

scholarly journals Non-indigenous macroalgal species in coralligenous habitats of the Marine Protected Area Isole Ciclopi (Sicily, Italy)

2021 ◽  
Vol 11 ◽  
pp. 31-44
Author(s):  
Luca Giuseppe Costanzo ◽  
Giuliana Marletta ◽  
Giuseppina Alongi
Keyword(s):  
Alien Species ◽  
Mediterranean Sea ◽  
Protected Area ◽  
Marine Protected Area ◽  
Eastern Mediterranean ◽  
Present Report ◽  
Eastern Coast ◽  
Remotely Operated Vehicle ◽  
High Coverage ◽  
The Mediterranean

Biological invasions are considered one of the main threats for biodiversity. In the last decades, more than 60 macroalgae have been introduced in the Mediterranean Sea, causing serious problems in coastal areas. Nevertheless, the impacts of alien macroalgae in deep subtidal systems have been poorly studied, especially in the coralligenous habitats of the eastern coast of Sicily (Italy). Therefore, within the framework of the programme “Progetto Operativo di Monitoraggio (P.O.M.)” of the EU Marine Strategy Framework Directive (MSFD), the aim of the present study was to gain knowledge on the alien macroalgae present in coralligenous habitats of the Marine Protected Area (MPA) Isole Ciclopi, along the Ionian coast of Sicily. By Remotely Operated Vehicle (ROV) videos and destructive samples analysed in the laboratory, five alien species were identified: Caulerpa cylindracea, Antithamnion amphigeneum, Asparagopsis armata, Bonnemaisonia hamifera, and Lophocladia lallemandii. Since A. amphigeneum was previously reported only in the western Mediterranean and Adriatic Sea, the present report represents the first record of this species in the eastern Mediterranean. The ROV surveys showed that the alien species do not have a high coverage and do not appear to be invasive in the coralligenous area of the MPA. Since ocean temperatures are predicted to increase as climate change continues and alien species are favoured by warming of the Mediterranean Sea, the risk of biotic homogenisation caused by the spread of alien species is realistic. Therefore, further studies are needed to assess the incidence and invasiveness of alien species in phytobenthic assemblages of coralligenous in the MPA.

Global warming decreases rainfall but increases short-duration rain-rates during heavy precipitation events in the eastern Mediterranean

2021 ◽  
Author(s):  
Moshe Armon ◽  
Francesco Marra ◽  
Chaim Garfinkel ◽  
Dorita Rostkier-Edelstein ◽  
Ori Adam ◽  
...  
Keyword(s):  
Global Warming ◽  
Short Duration ◽  
Eastern Mediterranean ◽  
Heavy Precipitation ◽  
Annual Rainfall ◽  
Cmip5 Models ◽  
The Future ◽  
Rain Rates ◽  
The Impact ◽  
Precipitation Events

&lt;p&gt;Heavy precipitation events (HPEs) in the densely populated eastern Mediterranean trigger natural hazards, such as flash floods and urban flooding. However, they also supply critical amounts of fresh water to this desert-bounded region. The impact of global warming on such events is thus vital to the inhabitants of the region. HPEs are poorly represented in global climate models, leading to large uncertainty in their sensitivity to climate change. Is total rainfall in HPEs decreasing, as projected for the mean annual rainfall? Are short duration rain rates decreasing, or rather increasing as expected from the higher atmospheric moisture content? Where are the changes more pronounced, near the sea or farther inland towards the desert? To answer these questions, we have identified 41 historical HPEs from a long weather radar record (1990-2014) and simulated them in the same resolution (1 km&lt;sup&gt;2&lt;/sup&gt;) using the convection-permitting weather research and forecasting (WRF) model. Results were validated versus the radar data, and served as a control group to simulations of the same events under &amp;#8216;pseudo global warming&amp;#8217; (PGW) conditions. The PGW methodology we use imposes results from the ensemble mean of 29 Coupled Model Intercomparison Project Phase 5 (CMIP5) models for the end of the century on the initial and boundary conditions of each event simulated. The results indicate that HPEs in the future may become more temporally focused: they are 6% shorter and exhibit maximum local short-duration rain rates which are ~20% higher on average, with larger values over the sea and the wetter part of the region, and smaller over the desert. However, they are also much drier; total precipitation during the future-simulated HPEs decreases substantially (~-20%) throughout the eastern Mediterranean. The meteorological factors leading to this decrease include shallower cyclones and the projected differential land-sea warming, which causes reduced relative humidity over land. These changing rainfall patterns are expected to amplify water scarcity &amp;#8211; a known nexus of conflict and strife in the region &amp;#8211; highlighting the urgent need for deeper knowledge, and the implementation of adaptation and mitigation strategies.&lt;/p&gt;

scholarly journals New records of the rare deep-water alga Sebdenia monnardiana (Rhodophyta) and the alien Dictyota cyanoloma (Phaeophyceae) and the unresolved case of deep-water kelp in the Ionian and Aegean Seas (Greece)

2019 ◽  
Vol 62 (6) ◽  
pp. 577-586 ◽  
Author(s):  
Frithjof C. Küpper ◽  
Konstantinos Tsiamis ◽  
Niko Rainer Johansson ◽  
Akira F. Peters ◽  
Maria Salomidi ◽  
...  
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
New Records ◽  
Eastern Mediterranean ◽  
Benthic Communities ◽  
Scuba Diving ◽  
First Record ◽  
Special Focus ◽  
East Mediterranean ◽  
Remotely Operated Vehicle

Abstract Parts of the macroalgal flora of the eastern Mediterranean remain incompletely known. This applies in particular to the circalittoral communities. This study, based upon 2 cruises in the Ionian and Aegean Seas, surveyed benthic communities from 40 to 150 m depth by remotely-operated vehicle (ROV) with a special focus on detecting communities of the Mediterranean deep-water kelp Laminaria rodriguezii. These were complemented by shallow-water surveys on adjacent coastlines by snorkelling and scuba diving. While no kelp could be detected at any of the sites surveyed, ROV surveys of northern Euboia Island revealed the first east Mediterranean record of Sebdenia monnardiana (Sebdeniales, Rhodophyta). Snorkelling surveys on the coast of southeast Kefalonia yielded the first record of the alien alga Dictyota cyanoloma in Greece. This paper reports rbcL and SSU sequences for Sebdenia monnardiana, and COI for Dictyota cyanoloma.

scholarly journals The Discovery and Preliminary Geological and Faunal Descriptions of Three New Steinahóll Vent Sites, Reykjanes Ridge, Iceland

2021 ◽  
Vol 8 ◽  
Author(s):  
James Taylor ◽  
Colin Devey ◽  
Morgane Le Saout ◽  
Sven Petersen ◽  
Inmaculada Frutos ◽  
...  
Keyword(s):  
Hydrothermal Vent ◽  
Harpacticoid Copepod ◽  
Sampling Strategy ◽  
Hydrothermal Activity ◽  
Remotely Operated Vehicle ◽  
Reykjanes Ridge ◽  
The North ◽  
Epibenthic Sledge ◽  
Bacterial Mats ◽  
Species Being

During RV MS Merian expedition MSM75, an international, multidisciplinary team explored the Reykjanes Ridge from June to August 2018. The first area of study, Steinahóll (150–350 m depth), was chosen based on previous seismic data indicating hydrothermal activity. The sampling strategy included ship- and AUV-mounted multibeam surveys, Remotely Operated Vehicle (ROV), Epibenthic Sledge (EBS), and van Veen grab (vV) deployments. Upon returning to Steinahóll during the final days of MSM75, hydrothermal vent sites were discovered using the ROV Phoca (Kiel, GEOMAR). Here we describe and name three new, distinct hydrothermal vent site vulnerable marine ecosystems (VMEs); Hafgufa, Stökkull, Lyngbakr. The hydrothermal vent sites consisted of multiple anhydrite chimneys with large quantities of bacterial mats visible. The largest of the three sites (Hafgufa) was mapped, and reconstructed in 3D. In total 23,310 individual biological specimens were sampled comprising 41 higher taxa. Unique fauna located in the hydrothermally venting areas included two putative new species of harpacticoid copepod (Tisbe sp. nov. and Amphiascus sp. nov.), as well as the sponge Lycopodina cupressiformis (Carter, 1874). Capitellidae Grube, 1862 and Dorvilleidae Chamberlin, 1919 families dominated hydrothermally influenced samples for polychaetes. Around the hydrothermally influenced sites we observed a notable lack of megafauna, with only a few species being present. While we observed hydrothermal associations, the overall species composition is very similar to that seen at other shallow water vent sites in the north of Iceland, such as the Mohns Ridge vent fields, particularly with peracarid crustaceans. We therefore conclude the community overall reflects the usual “background” fauna of Iceland rather than consisting of “vent endemic” communities as is observed in deeper vent systems, with a few opportunistic species capable of utilizing this specialist environment.

Diving to the Deep: Uncovering the Mysteries of Mid-Ocean Ridges

2009 ◽  
Vol 43 (1) ◽  
pp. 31-36
Author(s):  
Ian D. Jasper ◽  
Adam Ramsey
Keyword(s):  
Water Flow ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
Remotely Operated Vehicle ◽  
Frame Design ◽  
Ocean Ridges ◽  
City College ◽  
Directional Movement ◽  
Length Width ◽  
Light Color

AbstractLong Beach City College (LBCC) returns to the 2008 MATE Remotely Operated Vehicle (ROV) Competition with the Viking Super Agile Benthic Exploration ROV (SABER) ready for work. The purpose of this ROV is to explore the depths of the mid-oceanic ridges while taking temperature readings of black smokers, recovering samples and safely returning them to the surface. The ROV was designed with a frame made from buoyant PVC. The design made in SolidWorks greatly increases water flow, allowing it to glide through the water to a depth of about 30 m due to tether length. The length, width, and height of the ROV are 76 cm, 50 cm, and 28 cm, respectively. With a surprising 16 kg of weight, an average person could lift it easily, using the handles that are part of the frame design. LBCC’s ROV carries four cameras: a dual camera stereovision system, which creates a distance-measuring viewing system; a single high-resolution, low-light color camera with multi-directional movement; and an unfixed camera, which can be mounted anywhere for extra viewing. The five thrusters provide 2.9 kg of thrust each, enabling it to be quick and powerful. In order to complete the assigned tasks, a multi-function gripper was designed and built. This gripper has a built-in hook to grab the ocean bottom seismometer and help return it to the surface. The gripper has a channel cut into the middle of it to allow water flow, so the temperature sensor can be deployed properly and it can also easily pick up the lava samples.

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