Seafloor Conditions Research Articles

Megabenthic assemblages at the Hudson Canyon head (NW Atlantic margin): Habitat-faunal relationships

The distribution of megabenthic communities at the head of Hudson Canyon and adjacent continental shelf was studied by means of underwater video transects and still photo imagery collected using a towed camera system. The goal was to explore the relationships between faunal distribution and physical seafloor conditions and to test the hypothesis that increased seafloor heterogeneity in the Hudson Canyon supports a larger diversity of benthic communities, compared with the adjacent continental shelf. Hierarchical cluster analysis was performed to identify benthic assemblages as defined in imagery. The BIO-ENV procedure and the Canonical Correspondence Analysis were carried out to elucidate species groupings in relation to terrain variables extracted from bathymetric data. Species accumulation curves were generated to evaluate species turn over in and out of Hudson Canyon. The results indicate that seafloor morphology is the main physical factor related to benthic community composition and distribution. Assemblages dominated by sponges, zoanthids and cup corals colonized the canyon margins and flanks, and were associated with coarse-grained sediments, while sea pen assemblages were observed along muddy seafloor within the thalweg. An assemblage dominated by sea stars occurred on the shelf, associated with a sandy seafloor. Some assemblages were exclusively observed in the canyon area, suggesting that the increased variability of seafloor composition, together with the oceanographic processes specific to the canyon area, enhance beta diversity. The colonization by benthic suspension feeders within the canyon, in contrast to shelf assemblages, mainly composed of carnivores and detritus feeders could be favored the intense hydrodynamics at the canyon head that increase the availability of suspended organic matter.From the perspective of management and conservation of marine resources, the results obtained support the relevance of Hudson Canyon asa biodiversity hotspot. Such results are of particular significance in light of the recent action promoted by the Mid-Atlantic Fisheries Management Council, that restricts bottom trawling in most of the submarine canyons of the US Atlantic margin, including the Hudson Canyon, to protect cold-water corals from damage by fishing gear.

Secular distribution of highly metalliferous black shales corresponds with peaks in past atmosphere oxygenation

Highly metalliferous black shales (HMBS) are enriched in organic carbon and a suite of metals, including Ni, Se, Mo, Ag, Au, Zn, Cu, Pb, V, As, Sb, Se, P, Cr, and U ± PGE, compared to common black shales, and are distributed at particular times through Earth history. They constitute an important future source of metals. HMBS are relatively thin units within thicker packages of regionally extensive, continental margin or intra-continental marine shales that are rich in organic matter and bio-essential trace elements. Accumulation and preservation of black shales, and the metals contained within them, usually require low-oxygen or euxinic bottom waters. However, whole-rock redox proxies, particularly Mo, suggest that HMBS may have formed during periods of elevated atmosphere pO2. This interpretation is supported by high levels of nutrient trace elements within these rocks and secular patterns of Se and Se/Co ratios in sedimentary pyrite through Earth history, with peaks occurring in the middle Paleoproterozoic, Early Cambrian to Early Ordovician, Middle Devonian, Middle to late Carboniferous, Middle Permian, and Middle to Late Cretaceous, all corresponding with time periods of HMBS deposition. This counter-intuitive relationship of strongly anoxic to euxinic, localized seafloor conditions forming under an atmosphere of peak oxygen concentrations is proposed as key to the genesis of HMBS. The secular peaks and shoulders of enriched Se in sedimentary pyrite through time correlate with periods of tectonic plate collision, which resulted in high nutrient supply to the oceans and consequently maximum productivity accompanying severe drawdown into seafloor muds of C, S, P, and nutrient trace metals. The focused burial of C and S over extensive areas of the seafloor, during these anoxic to euxinic periods, likely resulted in an O2 increase in the atmosphere, causing short-lived peaks in pO2 that coincide with the deposition of HMBS. As metals become scarce, particularly Mo, Ni, Se, Ag, and U, the geological times of these narrow HMBS horizons will become a future focus for exploration.

PEMETAAN DAN KLASIFIKASI SEDIMEN DENGAN INSTRUMEN SIDE SCAN SONAR DI PERAIRAN BALONGAN, INDRAMAYU-JAWA BARAT

Berdasarkan hasil deteksi dasar laut menggunakan side scan sonar dalam pencitraan benda-benda di dasar laut dapat menghasilkan berbagai variasi gambar yang digunakan untuk pencitraan objek-objek dasar laut, selain itu dapat memberikan informasi dalam pengembangan wilayah pantai. Tujuan dari penelitian ini adalah visualisasi atau pemetaan dasar perairan dan klasifikasi sedimen atau objek di dasar laut secara kualitatif, sehingga dapat diketahui keadaan dasar laut. Interpretasi dan klasifikasi data akustik side scan sonar dilakukan secara kualitatif dengan menggunakan software Sonar Pro untuk melihat bentuk geometris dan keunikan dari suatu objek. Pengambilan contoh sedimen dilakukan pada 6 jalur transek dengan jarak antar transek 0.5 km. Setiap transek terdapat 3 buah stasiun sampel sedimen dan jumlah total adalah 18 sampel sedimen. Berdasarkan hasil pemetaan dasar laut daerah Balongan terdapat buangan sedimen, paritan dan kerukan sedimen, selain itu terdapat objek seperti box, mooring, potongan pipa, tali, pole.

Using local knowledge to project sea level rise impacts on wave resources in California

Sea level rise will have significant impacts on many coastal resources. Waves are an important resource in California, where they support the recreation of 1.1 million surfers who inject millions of dollars into local economies. The impacts of sea level rise on wave resource quality, however, are unknown. By examining the local knowledge of more than one thousand California surfers collected through an online survey, this study extrapolates their evaluations to estimate the susceptibility of California surf-spots to sea level rise based on the principle of tidal extrapolation. Vulnerability classifications are derived from the relationship between wave quality, tide effects, and sea floor conditions. Applying these classifications to 105 surf-spots in California evaluated by multiple respondents, we project that as a result of sea level rise by 2100: 16% of surf-spots are Endangered due to drowning; 18% are Threatened, but could adapt if natural shoreline processes are not impeded; and 5% might improve as rising sea levels increase the likelihood they will experience optimal conditions. These projections are significant not only for the many surfers who depend on surf-spots, but also for the coastal communities who rely on the availability of high quality wave resources. Results from this study also have important implications for when and how managers might take surf-spot quality and vulnerability into consideration through coastal adaptation. Lastly, this study establishes a baseline of wave resource quality in California and suggests that this baseline will shift as wave quality changes over the coming century.

Evolutionary trend of Zoophycos morphotypes from the Upper Cretaceous–Lower Miocene in the type pelagic sections of Gubbio, Italy

About 200 Zoophycos specimens, including 90 specimens studied in detail, have been analysed in the continuous Upper Cretaceous–Lower Miocene pelagic sedimentary type sections of the Gubbio area (the Contessa Highway, Contessa Quarry and Bottaccione sections, Northern Apennines). The sediments are reddish to grey limestones and marls of the Scaglia Group and marls with volcaniclastic deposits of the Bisciaro Formation. The aim was to examine the evolutionary trend of what is probably the most debated trace fossil of all time, from the Upper Cretaceous to Lower Miocene. Despite having been found in beds ranging from the Cambrian to the present, no consensus has been reached regarding mode of construction, tracemaker or ethological explanation for Zoophycos. Four Zoophycos morphotypes are recognized at Gubbio showing variations of major and minor lamellae, apex, lobes and whorls: the Cretaceous–Eocene cone-shaped type 1, the Upper Eocene–Middle Oligocene helicoidal type 2, the Oligocene lobate type 3 and the Upper Oligocene–Lower Miocene flat type 4. The very high ichnodensity in some beds (hundreds of specimens in discrete levels of the Bisciaro Formation, now destroyed by quarrying) seems to find explanation in abnormal concentrations of phytodetritus and organic matter on the seafloor in some periods. This very high abundance in discrete levels reflects a change in sedimentation and seafloor conditions at pre-flysch deposition. Due to such high ichnodensity, many adjacent specimens display deformed outer margins. Taphonomic analysis shows a variation of whorls, laminae and U-shaped lobes, reflecting ontogenetic development of the tracemaker(s) (?sipunculid worms).

Initial results of batch reactor experiments to determine sulphide oxidation rates and trace metal release under seafloor conditions

"Initial results of batch reactor experiments to determine sulphide oxidation rates and trace metal release under seafloor conditions." Applied Earth Science, 125(2), pp. 88–89

Fast Unsupervised Seafloor Characterization in Sonar Imagery Using Lacunarity

A new unsupervised approach for characterizing seafloor in side-looking sonar imagery is proposed. The approach is based on lacunarity, which measures the pixel-intensity variation, of through-the-sensor data. No training data are required, no assumptions regarding the statistical distributions of the pixels are made, and the universe of (discrete) seafloor types need not be enumerated or known. It is shown how lacunarity can be computed very quickly using integral-image representations, thereby making real-time seafloor assessments on-board an autonomous underwater vehicle feasible. The promise of the approach is demonstrated on high-resolution synthetic-aperture-sonar imagery of diverse seafloor conditions measured at various geographical sites. Specifically, it is shown how lacunarity can effectively distinguish different seafloor conditions and how this fact can be exploited for target-detection performance prediction in mine-countermeasure operations.

Stable seafloor conditions, sea level and food supply during the latest Maastrichtian at Brazos River, Texas

Abstract The Cretaceous/Paleogene (K/Pg) boundary extinction event is inextricably linked to the Chicxulub impact. Environmental changes like sea level changes and changes in food supply prior to or after the impact could however have contributed to the biotic turnover. In this study, benthic foraminifera from two cores from the Brazos River area in Texas are quantitatively analyzed in order to reconstruct environmental changes across the K/Pg boundary. Cluster analysis as well as non-metric multidimensional scaling reveals three distinct benthic foraminiferal assemblages: an upper Maastrichtian assemblage, a post-impact assemblage, and a lower Danian assemblage. The rather uniform upper Maastrichtian assemblage at Brazos River, composed of e.g. Clavulinoides midwayensis, Gavelinella dumblei, Cibicidoides harperi, Gyroidinoides aequilateralis and Bulimina kickapooensis, indicates a stable paleodepth of about 75–100 m up to the K/Pg boundary. Food supply indicators such as percentage Buliminaceae and foraminiferal numbers suggest a relatively low and stable food supply during this interval. Environmental disruption caused by the Chicxulub impact led to the settlement of a typical pioneer assemblage, characterized by endobenthic morphotypes such as Ammobaculites spp. and Pseudouvigerina naheolensis. During the early Danian, the typical Midway-type benthic foraminiferal shelf fauna (e.g. Alabamina midwayensis, Anomalinoides acutus, Gyroidinoides subangulatus, Praebulimina carseyae and Cibicidoides alleni) developed, indicating a paleodepth of 75–100 m. No clear water depth changes can be derived from the benthic foraminiferal record during this interval, although the sedimentary record suggests a shallowing followed by a transgressive pulse in Zone P1a. Food supply indicators suggest a lower food supply in the early Danian than during the upper Maastrichtian. Because of the stability of the late Maastrichtian environment we conclude that environmental disruption caused by the impact was most likely the principal cause of the benthic foraminiferal turnover across the K/Pg boundary observed at Brazos River.

Ichnofabrics of shallow-marine mudstone, the result of changing environmental conditions: an example from the Middle Jurassic ore-bearing clay from southern Poland

Analysis of the trace fossil association and ichnofabrics from a Middle Jurassic shallow-marine mudstone, referred to as the Ore-Bearing Częstochowa Clay Formation, is used to reconstruct the seafloor conditions and identify the factors responsible for their changes. The trace fossil association contains Chondrites, Trichichnus, Palaeophycus, Planolites, Protovirgularia, ?Rosselia, Schaubcylindrichnus, Taenidium, cf. Tasselia, Thalassinoides, and five types of pyritized burrow. The association represents the distal expression of Cruziana ichnofacies, temporarily changing to a more proximal development. The ichnofacies suggests that the depositional site was located in the lower offshore to offshore-transition zone, periodically passing to the distal lower shoreface. Eight subtypes of the ichnofacies are recognized, reflecting variations in seafloor oxygenation, sedimentation rate, and benthic food content. The sequence of ichnofabrics 1a–1b–2a–2b reflects increasing oxygenation; ichnofabrics 4a, 4b, and 5 record high sedimentation rates, whereas ichnofabric 3 reflects sediment starvation. Vertical changes of ichnofabrics reflect major fluctuations in basin depth and distance from the shoreline, which partly correlate with previously recognized transgressive–regressive cycles. However, they do not record minor variations of the shoreline position.

A GIS-based decision-support approach to deepwater drilling-hazard maps

Drilling-hazard maps — sometimes known as drilling-favorability maps — derived from geophysical data are important tools for communicating the spatial variability of geohazards that might be encountered during deepwater operations. Multiattribute utility theory (MAUT) can be generalized to GIS-based map environments to produce drilling-hazard maps within a structured logical framework that allows for more flexibility and easier sensitivity analysis than simple rule-based approaches. The method is applied in a deepwater area that covers about 2000 km2 of complicated seafloor and shallow-subsurface conditions.

Early Eocene environmental development in the northern Peri-Tethys (Aktulagay, Kazakhstan) based on benthic foraminiferal assemblages and stable isotopes (O, C)

Abstract The Aktulagay section in Kazakhstan provides an expanded northern Tethyan record of the middle Ypresian (calcareous nannoplankton zones NP11–13, ~ 54–50 Ma), including the Early Eocene Climatic Optimum (EECO). The marl sequence features a series of sapropel beds, observed throughout the Peri-Tethys, indicative of the basin-wide occurrence of episodic hypoxic events. In order to unravel the paleoenvironmental evolution at Aktulagay during this period of global warming, we investigated the benthic foraminiferal record by means of a detailed multivariate analysis of the > 63 μm fraction, as well as through stable isotopic (C, O) investigations on excellently preserved benthic foraminiferal specimens. The Alashen Formation (NP11 to lower NP12; ~ 54 to 52.5 Ma), in the lower part of the sequence, contains a diverse assemblage of deep outer neritic (~ 200–250 m) benthic foraminifera, with common Pulsiphonina prima and Paralabamina lunata. The seafloor conditions are interpreted as initially (54 Ma) well-ventilated and oligo- to mesotrophic, gradually changing to more eutrophic and oxygen-limited, culminating in more permanent low oxygen conditions and eutrophy in the sapropel-bearing Aktulagay B1 unit (middle NP12; ~ 52.5-52 Ma). The latter conclusion is corroborated by the dominance of Anomalinoides acutus and Bulimina aksuatica and the lower diversity. Also the upward migration of endobenthic species to the sediment–water interface, as suggested by rising δ13Cendobenthic values, supports this interpretation. A transgression, which flooded lowlands, might have caused this development. In the Aktulagay B2 unit (top NP12–NP13; ~ 52–50 Ma), benthic foraminiferal assemblages dominated by Epistominella minuta suggest an oligotrophic environment, with transient pulses of phytodetritus and moderate ventilation. The Aktulagay B2 unit coincides with the peak temperature interval of the EECO, as indicated by its position close to the base of NP13 and rising δ13Cepibenthic values. Large river plumes, episodically reaching the area, in a monsoonal climatic context, might explain this basin development. Although it is not unlikely that some of the observed patterns are related to long-term climate change, it can currently not be excluded that changing paleogeography and variable connections to the Tethys, Atlantic and the Arctic Ocean were responsible for the long-term period with dysoxia and anoxia during deposition of the sapropel beds at the Peri-Tethyan seafloor. The evolution of the basin as observed in Aktulagay shows similarities to the evolution of the North Sea Basin as observed in Denmark, suggesting that these basins were connected during the Early Eocene.

Depositional environments of Lower Cretaceous (Ryazanian– Barremian) sediments from Wollaston Forland and Kuhn Ø, North-East Greenland

Lower Cretaceous sediments from the Wollaston Forland–Kuhn Ø area in North-East Greenland have been analyzed for stable carbon isotopes, total organic carbon (TOC) content, and major and trace elements, aiming at a lithological characterization and reconstruction of the depositional environments. The marine sediments of Ryazanian–Barremian age were deposited in North-East Greenland directly after a major Late Jurassic – earliest Cretaceous rifting event. The Lower Cretaceous post-rift sediments are composed of fossiliferous calcareous mud- and marlstones assigned to the Albrechts Bugt (upper Ryazanian – Valanginian) and Rødryggen (Hauterivian) Members. The calcareous sediments are commonly sandwiched between black mudstones of Late Jurassic – earliest Cretaceous (Bernbjerg Formation) and mid Cretaceous (unnamed formation) age. The carbon isotope curves present the first record for the Lower Cretaceous (upper Ryazanian – Barremian) of North-East Greenland. The Ryazanian – Hauterivian sediments are characterized by a mixture of terrigenous detrital matter (quartz, clay minerals, heavy minerals) similar to average shale, with varying CaCO3 concentrations. The Barremian black mudstones on the contrary have lower CaCO3 and higher clay mineral contents. The deposition of the Bernbjerg Formation took place under anoxic bottom water conditions. The depositional environment of the Albrechts Bugt and Rødryggen Members is characterized by well-oxygenated sea-floor conditions, hemipelagic sedimentation of fine-grained terrigeneous detrital matter, and biogenic carbonate settling. After this relatively short interval of carbonate sedimentation under oxic conditions, bottom waters were affected by dysoxic conditions, responsible for the burial of organic matter in the Barremian.

Paleoenvironmental changes during the Middle Eocene Climatic Optimum (MECO) and its aftermath: The benthic foraminiferal record from the Alano section (NE Italy)

The Middle Eocene Climatic Optimum (MECO) was one of the most severe, short-term global climate perturbations of the Cenozoic that occurred at ca. 40Ma and was characterized by a gradual 4–6°C temperature increase of intermediate and deep-waters. We investigated the response to the MECO of the deep-sea ecosystem in the central-western Tethys, through a quantitative study of bathyal benthic foraminiferal assemblages in the expanded and continuous Alano section (northeastern Italy), for which data on stratigraphy, lithology, isotope and trace element geochemistry, and calcareous microplankton were available. During the gradual warming of MECO (lasting between 350 and 650kyr) marine export productivity increased, causing a significant but transient restructuring of benthic foraminiferal faunas, which changed gradually from assemblages typical for oligo-mesotrophic sea floor conditions to assemblages indicative of more eutrophic conditions. Just after the peak MECO conditions, which lasted less than 100kyr, a prolonged phase of environmental instability (~500kyr) occurred, marked by even more highly increased export productivity leading to bottom-water oxygen depletion, as reflected in deposition of organic-rich sediments and multiple peaks of bi-triserial opportunistic benthic foraminiferal taxa, including buliminids, bolivinids and uvigerinids. The high productivity may have been caused by a strong influx of nutrient-bearing fresh water into the basin, due to the increased vigour of the hydrological cycle during the warm period, and this increased fresh-water influx might have been a factor in enhancing water column stratification, thus exacerbating the hypoxic conditions, which persisted about 400–500kyr. After deposition of the organic-rich layers the environmental perturbation ended, and benthic foraminiferal assemblages recovered while conditions became very similar to what they were before the MECO. The environmental disturbance during and directly after the MECO thus strongly but transiently affected benthic foraminiferal assemblages in the central western Tethys.

The effect of methane hydrate morphology and water saturation on seismic wave attenuation in sand under shallow sub-seafloor conditions

A better understanding of seismic wave attenuation in hydrate-bearing sediments is needed for the improved geophysical quantification of seafloor methane hydrates, important for climate change, geohazard and economic resource assessment. Hence, we conducted a series of small strain (<10−6), seismic frequency (50–550Hz), laboratory resonant column experiments on synthetic methane hydrate-bearing sands under excess-water seafloor conditions. The results show a complex dependence of P- and S-wave attenuation on hydrate saturation and morphology. P- and S-wave attenuation in excess-water hydrate-bearing sand is much higher than in excess-gas hydrate-bearing sand and increases with hydrate saturation between 0 and 0.44 (the experimental range). Theoretical modelling suggests that load-bearing hydrate is an important cause of heightened attenuation for both P- and S-waves in gas and water saturated sands, while pore-filling hydrate also contributes significantly to P-wave attenuation in water saturated sands. A squirt flow attenuation mechanism, related to microporous hydrate and low aspect ratio pores at the interface between sand grains and hydrate, is thought to be responsible for the heightened levels of attenuation in hydrate-bearing sands at low hydrate saturations (<0.44).

Perturbation of a Tethyan coastal environment during the Paleocene–Eocene thermal maximum in Tunisia (Sidi Nasseur and Wadi Mezaz)

Despite the large number of studies on the Paleocene–Eocene thermal maximum (PETM), the knowledge of environmental and biotic responses in shallow marine environments remains quite poor. Benthic foraminiferal assemblages of the Sidi Nasseur and Wadi Mezaz sections in Tunisia were studied quantitatively and the paleoecologic interpretations provide new insights into the complex relationship between PETM global warming and perturbations of shallow marine settings. These sections expose upper Paleocene to lower Eocene shales and marls of the El Haria Formation up to the phosphate layers of the Chouabine Formation underlying the El Garia limestones. The Sidi Nasseur section contains a more complete and expanded Paleocene–Eocene boundary interval compared to Wadi Mezaz, although being truncated at the top. The Wadi Mezaz section contains a more complete post-PETM interval. The studied interval can be subdivided into a sequence of 4 biofacies, representing respectively a latest Paleocene biofacies, two PETM biofacies and one post-PETM Eocene biofacies.The latest Paleocene biofacies 1 consists of numerous calcareous benthic foraminifera (e.g. Anomalinoides midwayensis, Frondicularia aff. phosphatica and various Bulimina and Lenticulina species), abundant non-calcareous taxa (Haplophragmoides) and rare planktic foraminifera, indicating a slightly hypersaline eutrophic inner neritic to coastal environment, regularly interrupted by oxygen deficiency (moderate dysoxia). During the latest Paleocene, this highly productive environment shallowed as indicated by the increasing abundances of A. midwayensis. The variable dominance of non-calcareous agglutinated taxa in biofacies 1 indicates post-mortem dissolution effects. The TOC δ13Corg record reveals a sharp negative excursion, marking the base of the Eocene. In general, the absence of lithologic changes, an increasing sedimentation rate and absence of reworking indicate that the initial part of the PETM is complete and expanded in the Sidi Nasseur section. A sharp faunal turnover coincides with this negative δ13Corg excursion and is characterized by the disappearance or diminution of common Paleocene taxa in this area. During the PETM, benthic foraminifera are less abundant and consist of opportunistic non-calcareous taxa together with deeper dwelling (middle neritic) lagenids and buliminids (biofacies 2 and 3). Planktic foraminifera, dominated by flat-spired Acarinina (mainly A. multicamerata), become more abundant, as observed in many open marine sequences worldwide. All these faunal parameters suggest more stressed probably severe dysoxic sea floor conditions within a transgressive phase during the onset of the PETM. An estimation of the total duration of the Sidi Nasseur PETM interval is difficult to establish, yet the lack of recovery carbon isotope values suggests that the preserved PETM interval reflects only a part of the CIE “core”. The top of the PETM interval is truncated due to local (?) erosion during the early Eocene. The Eocene recovery fauna is mainly composed of Lenticulina and Stainforthia species (biofacies 4), indicating restricted coastal to hyposaline lagoonal eutrophic conditions, distinctly different from earlier environmental conditions.

Acoustic measurement of the Deepwater Horizon Macondo well flow rate

On May 31, 2010, a direct acoustic measurement method was used to quantify fluid leakage rate from the Deepwater Horizon Macondo well prior to removal of its broken riser. This method utilized an acoustic imaging sonar and acoustic Doppler sonar operating onboard a remotely operated vehicle for noncontact measurement of flow cross-section and velocity from the well's two leak sites. Over 2,500 sonar cross-sections and over 85,000 Doppler velocity measurements were recorded during the acquisition process. These data were then applied to turbulent jet and plume flow models to account for entrained water and calculate a combined hydrocarbon flow rate from the two leak sites at seafloor conditions. Based on the chemical composition of end-member samples collected from within the well, this bulk volumetric rate was then normalized to account for contributions from gases and condensates at initial leak source conditions. Results from this investigation indicate that on May 31, 2010, the well's oil flow rate was approximately 0.10 ± 0.017 m(3) s(-1) at seafloor conditions, or approximately 85 ± 15 kg s(-1) (7.4 ± 1.3 Gg d(-1)), equivalent to approximately 57,000 ± 9,800 barrels of oil per day at surface conditions. End-member chemical composition indicates that this oil release rate was accompanied by approximately an additional 24 ± 4.2 kg s(-1) (2.1 ± 0.37 Gg d(-1)) of natural gas (methane through pentanes), yielding a total hydrocarbon release rate of 110 ± 19 kg s(-1) (9.5 ± 1.6 Gg d(-1)).

POTENTIAL ENERGY OF OCEAN CURRENT FOR ELECTRIC POWER GENERATIONIN COASTAL AREAS OF EAST FLORES, NTT

&lt;p&gt;The electrical energy is one of the important needs for coastal communities particularly in small islands that has not reached by national electricity network. In order to fulfill this particular electricity needs, we do variety diversification efforts, such as the utilization of the ocean currents. The purpose of this survey is to recognize the morphology of seafloor and characteristic of hydro-oceanography as a fixed reference location in using the current energy. The study area is in the Larantuka Strait between Flores and Adonara islands which is part of the Flores Strait, East Nusatenggara Province. The methods of this study are current measurements, tidal and meteorological parameter observations, condition of coastal morphology and seafloor of the study area. The result show that, the location for turbine position is in area with relatively gentle slope morphology at a 20 meters water depth and it is close to local community. Based on the analysis of ADCP mobile current measurement, the minimum current velocity is 0.004 m/sec and maximum 3.68 m/sec. Whereas, from the ADCP static measurements the current velocity is from 0.002 m/sec to 2.83 m/sec. This condition is closely related to the semi-diurnal tide type in the study area, with two pairs of flood and web events within 24 hours. Therefore, the results of ocean current energy analysis indicate that the study area is very potential for using as a power plant location.&lt;/p&gt;&lt;p&gt;Keywords: potential energy of ocean currents, power plants, energy diversification, Larantuka Strait, East Flores&lt;/p&gt;

POTENTIAL ENERGY OF OCEAN CURRENT FOR ELECTRIC POWER GENERATIONIN COASTAL AREAS OF EAST FLORES, NTT

The electrical energy is one of the important needs for coastal communities particularly in small islands that has not reached by national electricity network. In order to fulfill this particular electricity needs, we do variety diversification efforts, such as the utilization of the ocean currents. The purpose of this survey is to recognize the morphology of seafloor and characteristic of hydro-oceanography as a fixed reference location in using the current energy. The study area is in the Larantuka Strait between Flores and Adonara islands which is part of the Flores Strait, East Nusatenggara Province. The methods of this study are current measurements, tidal and meteorological parameter observations, condition of coastal morphology and seafloor of the study area. The result show that, the location for turbine position is in area with relatively gentle slope morphology at a 20 meters water depth and it is close to local community. Based on the analysis of ADCP mobile current measurement, the minimum current velocity is 0.004 m/sec and maximum 3.68 m/sec. Whereas, from the ADCP static measurements the current velocity is from 0.002 m/sec to 2.83 m/sec. This condition is closely related to the semi-diurnal tide type in the study area, with two pairs of flood and web events within 24 hours. Therefore, the results of ocean current energy analysis indicate that the study area is very potential for using as a power plant location.Keywords: potential energy of ocean currents, power plants, energy diversification, Larantuka Strait, East Flores

Global Habitat Suitability for Framework-Forming Cold-Water Corals

Predictive habitat models are increasingly being used by conservationists, researchers and governmental bodies to identify vulnerable ecosystems and species' distributions in areas that have not been sampled. However, in the deep sea, several limitations have restricted the widespread utilisation of this approach. These range from issues with the accuracy of species presences, the lack of reliable absence data and the limited spatial resolution of environmental factors known or thought to control deep-sea species' distributions. To address these problems, global habitat suitability models have been generated for five species of framework-forming scleractinian corals by taking the best available data and using a novel approach to generate high resolution maps of seafloor conditions. High-resolution global bathymetry was used to resample gridded data from sources such as World Ocean Atlas to produce continuous 30-arc second (∼1 km2) global grids for environmental, chemical and physical data of the world's oceans. The increased area and resolution of the environmental variables resulted in a greater number of coral presence records being incorporated into habitat models and higher accuracy of model predictions. The most important factors in determining cold-water coral habitat suitability were depth, temperature, aragonite saturation state and salinity. Model outputs indicated the majority of suitable coral habitat is likely to occur on the continental shelves and slopes of the Atlantic, South Pacific and Indian Oceans. The North Pacific has very little suitable scleractinian coral habitat. Numerous small scale features (i.e., seamounts), which have not been sampled or identified as having a high probability of supporting cold-water coral habitat were identified in all ocean basins. Field validation of newly identified areas is needed to determine the accuracy of model results, assess the utility of modelling efforts to identify vulnerable marine ecosystems for inclusion in future marine protected areas and reduce coral bycatch by commercial fisheries.

The Paleocene–Eocene thermal maximum (PETM) in Svalbard — clay mineral and geochemical signals

For the first time the Paleocene–Eocene Thermal Maximum (PETM) interval has been identified in drillcores and field outcrops from the Paleogene Central Basin in Svalbard, based on mineralogical and geochemical information. Grumantbyen and Frysjaodden formations, a more than 300 m thick Paleogene interval, representing deltaic, delta-influenced marine shelf and deep water slope environments. The PETM has been recognized in the deepest and most distal deposits in the lower parts of the Frysjaodden Formation. Here, this global event is displayed in clay mineralogical distributions as significantly increased kaolinite abundances reflecting a period with intensified chemical weathering in the land areas surrounding this Paleogene basin. The period was characterized by dominantly reducing sea floor conditions, as seen in the Th/U distribution and the well developed parallel lamination in the pyrite-rich shales; all to be expected during an interval with increased temperature and precipitation.