Sea Depth Research Articles

Review on Fixed and Floating Offshore Structures. Part II: Sustainable Design Approaches and Project Management

Offshore structures exist in a variety of forms, and they are used for a variety of functions in varied sea depths. These structures are tailored for certain environments and sea depths. Different actions for suitable equipment selection, platform type design, and drilling/production processes are required for the applications of these offshore structures, as given in Part I. This paper is the second part, which outlines various processes, loads, design approaches and project management of offshore platforms. To achieve these, proper planning must be conducted for lifting, transportation, installation, design, fabrication, and commissioning of these offshore platforms. Some historical developments of some offshore structures are presented, and some project planning routines are undertaken in this research. The ultimate goal is to provide a general overview of the many processes of offshore platform design, construction, loadout, transportation, and installation. Some discussions on the design parameters such as water depth and environmental conditions were presented. It also lists various software programs used in engineering designs covering software programs for structural analysis, 3D rendering, computer-aided design (CAD), hydrodynamic design, oceanic flow analysis, offshore structures analysis, mathematical modelling, coding/algorithm development software, and programming software to aid analytical calculations. The review also includes information on cutting-edge offshore platforms and industry advancements. Ultimately, for long-term operations, various types of offshore platforms for specific seawater depths are available.

Analytical Approach for Estimation of Wave Transmission Coefficient for Π-Shaped Floating Breakwater

This study presents a simplified analytical approach, based on power transmission theory, to estimate the transmission coefficient of a π-shaped floating breakwater (FB) with finite width. In evaluating the transmitted wave power, this approach considers both the incident wave kinetic power and the heave oscillation of the FB. Additional power due to the acceleration of the floating body and the hydrodynamic mass increases the transmitted wave power behind the FB and consequently increases the transmission coefficient. The proposed theoretical approach is validated using laboratory-scale experimental data obtained from the literature for π-shaped FB. The results of the proposed approach are in good to excellent agreement with those of experimental studies. In addition, the reliability of the proposed approach is assessed by comparing its results with those of other theoretical models. The effects of sea depth, relative draft, and incident wave height on the magnitude of the transmission coefficient are examined. It is found that the effect of the incident wave height distinguishes the proposed model from others in the existing literature.

Microplastics Affect the Inflammation Pathway in Human Gingival Fibroblasts: A Study in the Adriatic Sea.

The level of environmental microplastics in the sea is constantly increasing. They can enter the human body with food, be absorbed through the gut and have negative effects on the organism’s health after its digestion. To date, microplastics (MPs) are considered new environmental pollutants in the air sea and they are attracting wide attention. The possible toxic effects of MPs isolated at different sea depths of 1, 24 and 78 m were explored in an in vitro model of human gingival fibroblasts (hGFs). MPs isolated from the sea showed different size and were then divided into different sample groups: 1, 24 and 78 m. The results obtained revealed that MPs are able to activate the inflammatory pathway NFkB/MyD88/NLRP3. In detail, the exposure to MPs from 1 and 78 m led to increased levels of inflammatory markers NFkB, MyD88 and NLRP3 in terms of proteins and gene expression. Moreover, cells exposed to MPs showed a lower metabolic activity rate compared to unexposed cells. In conclusion, these findings demonstrate that the inflammation process is stimulated by MPs exposure, providing a new perspective to better understand the intracellular mechanism.

Sinking particles in the Black Sea waters: Vertical fluxes of elements and pyrite to the bottom, isotopic composition of pyrite sulfur, and hydrogen sulfide production

The Black Sea is the largest anoxic basin with hydrogen sulfide at depths below 100 m. Anoxic condition significantly affects fluxes of particulate matter due to consuming organic material for sulfate reduction and syngenetic pyrite formation. Composition of sinking particles was studied for 6 water depths of the Black Sea (100–1750 m) with deployment period of over one year. As a result, the data on chemical and mineral composition of sinking particles including the contents of reduced sulfur species (acid volatile sulfides and Cr reducible species) and isotopic composition of Cr reducible sulfur species were obtained.Mineral composition of trapped material changes with depth mainly due to dissolution of plankton carbonate shells, which decreases to the bottom to reach 90%, and also due to oxidation of organic carbon (by 59%). While sinking, particulate matter loses Fe, S, U, Co, Mo, Tl, and Ag to the least extent. Framboidal pyrite appears in sinking particles in the upper part of anoxic water column shallower than 180 m. Its quantity increases down to the deeper waters amounting to 0.4 wt% of dry weight. The δ34S values in syngenetic pyrite from depths of 980, 1680, and 1775 m range from −42.2 to −42.6‰ vs. VCDT and were found to be close to those of sulfur isotopic composition in dissolved hydrogen sulfide.Based on a decrease of particulate organic carbon flux, the annual production of hydrogen sulfide in 2015–2016 was calculated to be 5.9 Tg H2S /year, the main part of which (80%) generates above a depth of about 980 m. Our estimate of H2S consumption for pyrite formation in the water column is 0.030 Tg H2S /year (0.5% of annual H2S production) which is believed insignificant for hydrogen sulfide balance in the Black Sea.

Analysis of spatial distribution pattern and its influencing factors of the Tamarix chinensis population on the beach of the muddy coastal zone of Bohai Bay

To explore the spatial distribution pattern of the Tamarix chinensis population and the influencing factors in the muddy coastal zone of Bohai Bay, we studied the T. chinensis forest on the beach of the muddy area of Beihai New District, Binzhou City, Shandong Province. A combination of field investigations and laboratory-based sample analyses were used to measure and analyze the forest density, height, cover, distance from the sea, groundwater depth, soil salinity, basic soil physical properties and soil nutrients. The results showed that the coefficients of variation for the 18 soil and forest indices for T. chinensis were between 0.03 and 0.96; the coefficients of variation for forest density, soil Ca2+ and Na+ content were the greatest, followed by those for soil Mg2+, soil salt content, distance from sea, and available phosphorus, while those for soil bulk density, total phosphorus, pH and other indicators changed less. The population of T. chinensis on the beach of the coastal zone of the Yellow River Delta showed an aggregated distribution, and its aggregation intensity decreased with increasing spatial scale, and it tended to evolve into a random distribution on a larger scale. The spatial distribution of the T. chinensis population showed a certain density dependence; that is, the greater the density was, the greater the aggregation intensity. The reason for the aggregated distribution of the T. chinensis population was mainly related to the biological characteristics of the organism itself or to the interactions between its biological characteristics and environmental factors. T. chinensis forest density was significantly and negatively correlated with organic carbon, total phosphorus, Ca2+, and Na+ (P < 0.05) and very significantly and negatively correlated with available phosphorus (P < 0.01). The soil water content was significantly and positively correlated with the soil salt content, K+, and Na+ (P < 0.01) and significantly and negatively correlated with the distance from the sea and groundwater depth (P < 0.05). The soil salt content was significantly and positively correlated with K+, Na+, and nitrate nitrogen (P < 0.01) and significantly and negatively correlated with distance from the sea and groundwater depth (P < 0.05). K+ and Na+ were the main cations contributing to soil salinity in this T. chinensis forest. With an increase in the distance from the sea, the groundwater depth and forest density gradually increased, and the soil water content and soil salt content gradually decreased. Soil water content, soil salt content, K+, and Na+ content were the dominant factors affecting the spatial distribution pattern for the T. chinensis population in the coastal tidal flat of the Yellow River Delta, followed by organic carbon, ammonia nitrogen, and finally the Mg2+, SO42-, Cl- content, and distance from the sea. The population distribution pattern for T. chinensis was mainly affected by the water and salt conditions, which is a result of the long-term adaptation and evolution of the species within the coastal saline-alkaline environment. Therefore, in the planting management and protection of T. chinensis in the muddy coastal zone of Bohai Bay, we should try to maintain the aggregation growth characteristics of the population according to the adaptation mechanism and biological characteristics of different habitats and community types of T. chinensis, allowing other species to coexist with T. chinensis, and thus optimizing the habitat in the coastal zone.

Modeling of Internal Pressure Dynamics in Mass-Impregnated Nondraining HVDC Cables

Changing the current loading of mass-impregnated nondraining (MIND) power cables causes the pressure in the insulation to vary over a wide range. It is generally recognized that under certain conditions—typically after a large load reduction—the pressure becomes so low that shrinkage cavities (voids) form in the insulation and that partial discharges (PDs) may damage the insulation ignite. A finite-element model for temperature, electric field, and pressure dynamics throughout the insulation layer has been developed. Comparisons with previously obtained measurements on full-scale high voltage direct current (HVDC) subsea cable samples subjected to a variety of loading patterns, external pressures (sea depths), and ambient temperatures show that the model replicates the pressure behavior of the insulation reasonably well. Most importantly, the complicated viscoelastic properties of the lead sheath, which have a profound effect on the internal pressure dynamics and thereby on the prospects of forming potentially harmful cavities, appear to be sufficiently accurately modeled.

“False peak” creation in the Flynn Creek marine target impact crater

AbstractImpacts into marine targets are known to create abnormal crater morphologies. We investigate the formation of the ~4 km diameter Flynn Creek marine target impact crater using the iSALE hydrocode. We compare simulation results to topographic profiles, mineral pressure indicators, and breccia sequencing from drill cores to determine the most likely sea depth at this location at the time of impact (~360 Ma, Tennessee, USA): 700–800 m. Both the peak shock pressure produced by the impact and the mechanism(s) of central peak formation differ with sea depth. The large central mound of Flynn Creek could have been produced in three distinct ways, all requiring the presence of an ocean: (1) a relatively cohesive rim collapse deposit that reached the crater center as part of a ground flow and came to rest on top of the existing crater stratigraphy; (2) chaotic resurge of ejecta with the returning ocean that deposited at the crater center; (3) large uplift facilitated by the removal of overburden pressure from a deep ocean. The first two of these mechanisms create “false peaks” in which high‐shock uplifted material and original crater floor are buried beneath &gt; 200 m of relatively low shock material. Our simulations suggest that drilling of marine impact sites might require deeper than expected drill cores, so that any high‐pressure mineralogical indictors at depth can be accessed.

Sedimentation of the Oligocene-Lower Miocene clinoforms of the Maikop formation in the Eastern and Central Pre-Caucasus region as a key criteria for reservoir exploration

Oligocene-Lower Miocene clinoforms of the Maikop formation are productive in the Eastern and Central Pre-Caucasus region. In spite of commercial discoveries and long exploration history, Maikop formation is poor characterized by borehole data in the deep basins such as Terek-Caspian trough. Furthermore, there are challenges of the detail stratigraphic subdivision in the deep basins, correlation, sedimentary conditions and criteria of reservoirs exploration. Based on seismic and borehole data analysis, sequent-stratigraphic framework, distribution area, progradation direction, seismic unconformities and thicknesses of the 17 Maikop sequences are established. Estimation of the clinoforms height allowed reconstructing paleobathymetry and paleogeography of the Pre-Caucasus region in the Oligocene – Early Miocene. Clinoforms M1-M7 prograded from the northeast, sea depth increased from 300 to 450 m. During clinoforms M8 sedimentation, new provenance area appeared on the west, sea depth increases up to 800 m. Clinoforms M12-M16 prograded from the north, sea depth decreases from 480 to 270 m. To the end of the M17 sequence deposition, starved deep basin was totally compensated. Three morphologic types of the clinoforms are identified. Type I represents by tangential clinoforms up to 75 m of height, that interpreted as subaqueous delta. Type II are the sigmoid shelf-edge delta clinoforms up to 800 m of height. Clinoforms of type III are low-angle wedges, confined to the slope and floor of the deep basin. Height of the wedges does not exceed 270 m. In the topset of the shelf-edge deltas, shallow-marine sandstones and structural traps predicted, while basin floor fans and stratigraphic traps expected in the bottomset. Subaqueous deltas are regarded to stratigraphic traps, while the wedges are predominantly mud-prone.

Design and implementation of a swimming robot with pectoral fins only

AbstractThe use of swimming robots has increased widely in recent years due to the need of using them in situations where human intervention is difficult or not allowed. Exploring depths of seas, military interventions, or entering areas where the amount of water pollution is high that may threaten the lives of divers. In such cases, the best alternative for humans is to use swimming robots. This paper presents a swimming robot based on Labriform swimming mode. First, it starts with an analytical study of the effect of the fins shape on the performance of a robotic fish. The suggested design of the pectoral fins is concave. The effect of such a design would help largely in achieving the highest thrust in comparison to flat designs provided in the literature. Secondly, a variation in the velocity between the power and recovery strokes is accomplished and a maximum thrust can be obtained when the velocity of the power stroke is three times the velocity of recovery stroke. Thirdly, the kinematics and dynamics of the swimming robot are derived and an evaluation of the total hydrodynamic forces that are exerted on the robot’s body is studied via the computational fluid dynamics method from SOLIDWORKS® platform. Finally, the obtained results are compared to other designs in the literature in terms of some dimensionless numbers of biological fish to examine the efficiency. The proposed design has been validated theoretically and examined experimentally. The results of the simulation and practical experiments confirmed the validity of the design.

Bandgap matching strategy for organic photovoltaic cells in oceanic applications

With the development of aquatic monitoring in oceanic science and environmental protection via tens of thousands of electronic detectors and sensors, the exploitation of energy supply technology for such off-grid electronic devices in ocean informatics is an urgent issue to be addressed. In particular, researchers are seeking alternative candidates to supply power to devices connected to the internet of things in oceanic conditions with diverse light intensities. Herein, we report the potential of organic photovoltaic materials in oceanic applications. The wide-bandgap PM6:IO-4Cl cell achieves a champion efficiency of 23.11% at a sea depth of 5 m because of film absorption spectrum matching with photons passing through the body of water. This work confirms the potential of wide-bandgap organic materials in oceanic photovoltaic applications. • The potential of OPV devices in oceanic applications is evaluated • PM6:IO-4Cl device achieves 23.11% PCE at an ocean depth of 5 m • We confirm the superiority of wide-bandgap organic materials in oceanic OPV devices Efficient energy supply for electronic devices for ocean informatics is becoming increasingly important. In this work, Yang and co-authors find that wide-bandgap organic solar cells based on the PM6:IO-4Cl cell achieve a champion efficiency of 23.11% at a sea depth of 5 m because of an effective bandgap-matched absorption.

Suitability Area of Groupers (Serranidae) Cultivation in Floating Net Cage (FNC) System in Kepulauan Seribu

Aquaculture is one of the steps taken by the DKI Jakarta Provincial Government to manage fishery resources. Kepulauan Seribu, in recent years, has experienced a decline in the production of fresh fish; therefore, the cultivation of the Grouper floating system has become an alternative solution. Successful breeding is supported by site selection due to assembling on the terms of Groupers life that includes water quality and oceanography. Water quality parameters include salinity, pH, dissolved oxygen, and oceanographic parameters, that is, sea surface temperature, depth, and current velocity. The method of analysis in this research is descriptive spatial based on the overlay results of Landsat 8 image data processing and in situ measurement data during the field survey. The analyst statistics was descriptive to analyze the relationship between the region of conformity with the results of Grouper fish production. The results of the statistical and spatial analysis found that the location of floating net cages in the Kepulauan Seribu in the class is very appropriate and appropriate. Meanwhile, the relationship between regional suitability and Grouper production in the Kepulauan Seribu is weak because production is related to other driving factors.

Structural Imaging of Acoustic Survey Using a Deep-Towed Sub-Bottom Profiler and Hydrophone Cable

High-resolution images are required for the exploration of mineral resources on and beneath the deep seafloor. Under the Strategic Innovation Promotion Program launched by the Council for Science, Technology, and Innovation in Japan, we developed a survey system using a deep-towed acoustic source and receivers that produces very high-resolution subseafloor images. Our system uses a subbottom profiler as the acoustic source and a hydrophone cable as receivers. These instruments are towed near the seafloor by a remotely operated vehicle (ROV). The subbottom profiler generates chirp signals in the frequency band of 700–2250 Hz, and 32 hydrophones with a receiver interval of 1 m record the reflected waves. The system also includes two recorder units that record the acoustic wavefield with a sampling interval of 0.1 ms. We carried out field surveys at two locations in Japan: one site is in the Sea of Japan where gas hydrates were discovered and the other site is near Okinawa Island where a plume from a hydrothermal smoker was recorded by an ROV camera. Pre-stack depth migration was applied to the processed data using velocity models with a constant velocity gradient below the seafloor. The vertical resolution was 0.5–1 m depending on the depth, and the horizontal resolution was about ten times larger than the vertical resolution. The resulting images show that detailed subseafloor structures can be clearly imaged by the deep-towed system, even at sea depths greater than 1000 m.

Report of deep-sea epibiont ciliates (Ciliophora) from more than 1000 m depth of the Arabian Sea, Indian Ocean.

The present article deals with the report of 7 suctorian epibiont species viz. Thecacineta calix, Actinocyathula homari, Loricophrya bosporica, L. cf. stresemanni, Acinetides gruberi, Trematosoma rotunda and Brachyosoma sp. on benthic meiofauna collected from the deep Arabian Sea (> 1000 m). The data on the distribution and host prevalence of found species are discussed. The finds of other deep-sea ciliate species are also mentioned.

Optimal layout design of floating offshore wind farms

This paper proposes a method to optimize the layout design of floating offshore wind farms (FOWFs), in order to maximize the energy efficiency over a year. It is assumed that each wind turbine be installed on a semi-submersible platform, and that each floating platform be repositioned depending on wind conditions. The platform repositioning is realized by the aerodynamic force applied on the turbine's rotor, and the force vector on each turbine is adjusted by manipulating the axial induction factor and the nacelle yaw angle of each turbine. The design parameters for FOWF layout optimization are the neutral positions of the platforms, the anchor distance and angle, and the cable length. For a site with specific sea depth and wind rose, the layout design problem is formulated as a constrained optimization problem and is solved using an iterative optimization procedure. It is demonstrated that the developed method increases energy generation of a 6 × 6 FOWF by 2.4% compared to the regular layout, and gives comparable results with a published result that assumes a repositioning mechanism with additional actuators.

AN APPLICATION OF SOFT COMPUTING TECHNIQUES TO PREDICT DYNAMIC BEHAVIOUR OF MOORING SYSTEMS

A spread mooring system (SMS) allows a ship or a floating platform to moor the seafloor using multiple mooring lines at a restricted region with a fixed heading in harsh weather. These systems can be used for the operations of ships of different tonnage at different sea depths. The optimal design of these systems is a challenging engineering problem because of the effects of many design parameters and changing environmental conditions. Modern soft computing techniques allow difficult engineering problems to be solved easily and precisely and are becoming more and more popular. In this paper, Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) as soft computation techniques have been chosen to estimate the hawser tensions and displacements of a spread mooring system. The attained results show both techniques can give consistent indicators for the modelling of dynamic systems. Although these techniques performed very well, the ANFIS model is relatively superior to the ANN technique, considering the accuracy of hawser tensions and displacements in terms of the relative errors and coefficient of correlation obtained for the ANN and ANFIS.

Spatial-temporal variation of the Western Mediterranean Sea biodiversity along a latitudinal gradient

The Mediterranean Sea is a large marine ecosystem with high heterogeneity in both environmental and ecological characteristics. It presents clear gradients from north to south and west to east. It is also an important area in terms of biodiversity and conservation of vulnerable species, and it suffers from several cumulative human impacts, such as fishing and climate change. Previous studies have characterized spatial and temporal patterns of species distributions and biodiversity indicators. However, a comprehensive analysis combining a wide representation of biodiversity indicators is still missing. In this study, we examined spatial and temporal changes of marine communities along a latitudinal gradient over the continental shelf ecosystems (25–500 m depth) of the Western Mediterranean Sea, from the Gulf of Lion in the north to the Gibraltar Strait in the south. We used information from the MEDITS trawl scientific surveys from 1994 to 2018, and we calculated relevant indicators to investigate spatial and temporal patterns in the region. We selected several indicators measuring alpha (species richness, Shannon diversity index and Pielou evenness index) and beta (decomposing both turnover and nestedness) diversity, as well as previously studied indicators identified to be sensitive to fishing and climate change impacts (biomass-based and trophic-level based metrics). We assessed differences in these indicators for the surveyed community as a whole and for fish, crustaceans and cephalopods, separately, over five regions. Our results show clear latitudinal gradients in some indicators: we observe a reversed pattern between richness (decreasing from south to north) and biomass trends (increasing from south to north) for the demersal community. We also found a generalized increase in β-diversity in most regions with time, and a decline in the trophic level of the surveyed community. In addition, we identify a remarkable increase in several indicators when only considering the cephalopods group, and a general low environmental status for the North Catalan Sea. We discuss our results considering the differences between regions and taxa related to the fishing activity and environmental dynamics that can act at different scales. This in-depth analysis illustrates how to use a selection of indicators that combine the capacity to detect ecological changes from regional to sub-regional scales.

Lagrangian Coherent Structures and hypoxia in the Baltic Sea

The spatial and temporal variations of Lagrangian Coherent Structures (LCSs) in the Baltic Sea are extracted from finite-time Lyapunov exponent (FTLE) fields. A validated 3-D hydrodynamic model of the Baltic Sea coupled with a water quality model is applied for the years 2000–2009. The novelty of the work is on the variation of LCSs with the sea depth, the state of hypoxia and the possible relationship with the blooming patterns in the Baltic. The study reveals a variety of LCSs with a typical core diameter of 10–40 km and a duration of 2–7 days that are formed offshore in all the basins of the Baltic Sea. They occur throughout the year even during winter times when the sea at the northern basins is partially covered with ice. The LCSs are more abundant in the southern basins where extensive algae blooms occur. The dominant structures are large vortex dipoles and anti-rotating vortex pairs that are not limited to the surface water layer but spread to a depth of 143.5 m. Likely mechanisms for the formation and the spread of LCSs are Kelvin-Helmholtz type instabilities, Proudman-Taylor column and Ekman Spiral. In the vicinity of the shorelines, the LCSs are smaller in diameter scaling with the mean Rossby radius to around 5 km. In the southern basins of the Baltic Sea; the dissolved oxygen (DO) content is permanently below 2 mg/l at depths below 80 m. DO contents vary seasonally with high values during winter and early spring times as opposed to lower values during summer and autumn periods. During late summers, the decline in DO content appears related to the extensive algae blooming consuming oxygen through the decomposition process. The LCSs map the patterns of Algae blooms detected by satellites. The duration of Algae blooming agrees with the persisting time of LCSs as well as the spatial surface water extents. The major 2003 inflow (MBI) increased the seabed DO content only in the lower part of the Arkona Basin that lasted just for about 3 weeks. The inputs of DO from the rivers and the 2003 MBI were not sufficient to counteract the seabed hypoxia in the Baltic Proper for the years 2000–2009.

Shallow Water Resistance Estimation for a Riverine Light Patrol Boat using Computational Fluid Dynamics

For the design of naval ships, the operational environmental conditions in which ship navigation will take place must be taken into account. The present study presents the effect of shallow water on ship's drag. Numerical simulations using Computational Fluid Dynamics with the Star CCM+ Commercial Software has been performed for sea depths in which the BCFBC Shallow Draft River Combat Boat will perform operations. A full-scale validation campaign of the simulations with the built boat has been developed. The shallow water effect on ship total resistance and the residual resistance for different depths and speed has been evaluated.

Assessing the need for the designation of the Yellow Sea Particularly Sensitive Sea Area (PSSA)

With each passing decade, industrial and economic activities have increased the severe contamination of the Yellow Sea and marine pollution, caused by various pollutants, has reached an alarming level. One of the main sources of contamination are pollutants from the international shipping industry. Due to an increase in maritime trade volume, driven by the rapid economic growth of China and South Korea, the danger of polluting incidents caused by shipping activities such as accidental and operational discharges from ships continues to rise. The semi-enclosed Yellow Sea poses geographical disadvantages. The depth of the Yellow Sea is relatively shallow. The width of the Yellow Sea does not exceed over 400 nm. China, South Korea, and North Korea have a common interest in the Yellow Sea. Pollution incidents involving oil, hazardous and noxious substances (HNS), or other pollutants from ships which occur in the territorial sea of one of the Yellow Sea states may have serious impacts on the maritime zone of another. Due to narrow sea areas of the Yellow Sea, there is ongoing dispute over maritime boundary delimitation of the Exclusive Economic Zone (EEZ) in the Yellow Sea. Concurrent Chinese and South Korean jurisdictions exist. These disputes are the primary factor hampering regional cooperation when dealing with regulatory instruments in an overlapping EEZ area. This article serves as a starting point for discussion, to make the case for the necessity of a practical regulatory instrument and regional cooperation to prevent vessel-source pollution in the Yellow Sea. In order to overcome the jurisdictional issue in an overlapping EEZ area and effectively address it, this article argues that the designation of a Yellow Sea Particularly Sensitive Sea Area (PSSA) is required. This study is not only assessing need for PSSA designation, but it is reviewing the geographical and environmental significance of the Yellow Sea.

Global biogeography of the lower bathyal (700–3000 m) as determined from the distributions of cnidarian anthozoans

The Lower Bathyal (approximately 700–800 to 3000–3500 m depth) of the deep sea, until recently, had only been explored in areas of continental slopes. With the advent of remotely operated vehicles (ROVs), seamounts and ridges, which comprise the bulk of the seafloor at those depths, have been increasingly sampled, at least for megafaunal species. We compiled records of cnidarians obtained from the Ocean Biogeographic Information System (OBIS) along with records of octocorals identified during ROV dives in the NW Atlantic and Central Pacific among other places, and used them to test the validity of the Watling et al. (2013) lower bathyal provinces which were proposed on the basis of hydrography. In addition, all records were used to independently determine the presence of biogeographic provinces using the Infomap Bioregions network analysis approach. Both methods have their shortcomings, but the combined results suggest that most of the provinces proposed by Watling et al. (2013) were reasonably well delineated; some changes were needed, especially in the North Atlantic. Specifically, the North Atlantic province needs to be divided into eastern and western units and the boundaries of the Boreal NW Atlantic (=Northern Atlantic Boreal) should be extended southward. Several name changes for various provinces are also proposed. Apparent endemism for those provinces where sufficient records exist was at least 33%, much higher than the 10% normally used when evaluating shallow water biogeographic provinces.