Underwater Landscapes Research Articles

Benthic community zonation from mesophotic to deep sea: Description of first deep-water kelp forest and coral gardens in the Madeira archipelago (central NE Atlantic)

The Madeira archipelago has a unique underwater landscape that is characterised by narrow shelves, steep slopes and a large submarine tributary system that boosts primary productivity in oligotrophic waters and thus offers a potential for hotspots of biodiversity. Despite this, there have been limited deep-water exploration activities with less than five expeditions since the 1960s. Here, we investigated the seabed on the southern side of the Madeira-Desertas Ridge using a manned submersible along a 3.8 km long transect starting at 366 m depth up the ridge shelf until its top at 73 m. Benthic habitats and community composition were documented with video along a depth gradient from mesophotic to deep sea. Six distinct biotopes were recognised (three deeper, and three shallower than 115 m depth). Our results showed a rich biodiversity with deep biotopes characterised by sponges and non-reef-building corals (e.g., Pachastrella monilifera, Viminella flagellum, Eunicella verrucosa) and shallow biotopes comprising macroalgae and the gorgonian Paramuricea cf. grayi. The pronounced benthic zonation reflects the steep environmental gradient that includes high topographic variation, heterogeneous substrates, and bidirectional regular wave-motion at the shallow mesophotic part. Together with biotic factors, such as low density of sea urchins and presence of predatory fish, this environment with unusual deep light penetration, a mesoscale cyclonic eddy, and deep wave-motion, has allowed the establishment of a mature deep-water kelp population of Laminaria ochroleuca in the plateau (max. >100 individuals p/100 m2). At the same time, a conspicuous coral fauna was observed on a wide range of soft to hard bottoms with several species taking advantage of the favourable hydrodynamic regime and seawater properties together with substratum availability to create coral gardens. These habitats were previously not known from Madeira, and their newfound discovery in the archipelago merit further investigation and protection.

The first record of Asellota (Isopoda) from hydrothermal vent biotopes of the submarine Piip Volcano, Bering Sea, with descriptions of two new species of Munnopsidae

Three species of asellote isopods (Crustacea) were found in hydrothermal vent biotopes on the submarine Piip Volcano, Bering Sea, at the depth of 373–472 m. Collection was obtained during 82−nd cruise of the R/V Akademik M.A. Lavrentyev using ROV Comanche-18. One species of the family Janiridae was tentatively identified as Janiralata cf. bilobata. Two species of the family Munnopsidae, Eurycope andreyi sp. nov. and Ilyarachna piipaensis sp. nov. were described as new to science. Both new species differ from their congeners by the unusually broad pleotelson: in Eurycope andreyi sp. nov., it is not narrower than pereonite 5, in contrast to all other species of the genus; in Ilyarachna piipaensis sp. nov., the pleotelson is broader than pereonite 7 and cephalon, while the other Ilyarachna species show opposite proportions. The broad pleotelson is associated with the increase in the size of the pleopods occupying the entire internal volume of the pleotelson from its ventral side. Pleopods have a respiratory function and their increase can be an adaptation to the reducing conditions of hydrothermal biotopes on the volcano. Photos and video records of underwater landscapes and benthic hydrothermal communities showed that Eurycope andreyi sp. nov. is the most abundant macrobenthic species on the Southern summit of the volcano, where it reaches a density of up to 40 individuals per square decimeter on bacterial mats.

Angling counts: Harnessing the power of technological advances for recreational fishing surveys

As the popularity of recreational fishing gathers global momentum, so does the importance of knowing the number of active anglers and their spatial behaviour. Conventional counting methods, however, can be inaccurate and time-consuming. Here we present two novel methods to monitor recreational fishing applied in Kaunas water reservoir (ca 65 km2), Lithuania, comparing their performance to a conventional visual count. First, we employed a remotely piloted fixed wing drone which conducted 39 missions distributed over one year and compared its accuracy to conventional visual land or boat-based counts. With these data we developed a linear model to predict the annual number of anglers depending on weekday and ice conditions. Second, we used anonymous data from a popular GPS-enabled sonar device Deeper®, used by anglers to explore underwater landscapes and to find fish. The sonar usage probability was calibrated with angler observations from drones using Bayesian methods, demonstrating that at any given time ~2 % of anglers are using the sonar device during the open water season and ~15 % during the ice fishing season. The calibrated values were then used to estimate the total number of anglers, given the daily records of sonar usage in Kaunas water reservoir. The predicted annual number of anglers from both linear drone-based and Bayesian sonar-based methods gave similar results of 25 and 27 thousand anglers within the area during the period of day surveyed, which corresponded to nearly 110 thousand angling trips in the total reservoir area annually. Our study shows high potential of both drone and fish finder digital devices for assessing recreational fishing activities through space and time.

PHOTOGRAMMETRIC AND FLUORESCENCE SOLUTIONS FOR MONITORING OF HABITAT FORMING ORGANISMS

Abstract. The development and testing of innovative technologies and automated data analysis methodologies offer tools for the monitoring of complex marine ecosystems and the direct and indirect effects of climate change on natural heritage. Photogrammetric methods allow precise mapping of the underwater landscape as well as detailed three-dimensional (3D) reconstruction of marine structures, improving the study of complex marine ecosystems. Moreover, fluorescence analyses can provide critical information about the health status of marine organisms. Analysing the variations in their self-fluorescence, allow for early detect changes in their physiological state. These applications provide very useful data to evaluate the health state of biodiversity-rich 3D biogenic structures and make measurements of fine-scale changes, with greater precision than existing methodologies. This contribution shows a multidisciplinary approach to the design, development, and implementation of a technological solution based on the above-mentioned optical measuring systems. Such a system is characterized by a reflex camera, LED-based light sources, and filters to allow the analysis of the self-fluorescence signal. The proposed solution aspires to improve the standardization of monitoring plans through non-destructive fine-scale accurate data collection for image analysis and multi-temporal comparisons, providing challenging stepping-stones for habitat-forming anthozoan management and restoration activities. Initial results of tests carried out in controlled conditions are shown. The photogrammetric approach resulted in 3D reconstructions that allow the monitoring of deformations at millimetre scale. The fluorimetry methodology allowed to obtain high-resolution images with great repeatability, which enabled the identification of stressful status even in absence of geometric deformations. The proposed approaches and obtained results are discussed, together with potential issues related to their implementation in a real-world context adopting remotely operative vehicles.

A Biomimetic Approach as a Sustainably Architectural Design in Designing Resort Hotels: A Study Case in the Tourism Beach of Tanjung Karang, Regency of Donggala, Central Sulawesi, Indonesia

The Province of Central Sulawesi has an interestingly attractive potency of tourism beaches for tourists, such as white-sand beach, sunset spots, tropical beach forest, and the beauty of an underwater landscape, mainly coral reefs located in Tanjung Karang, the Regency of Donggala. The typographic preservation of this tourism destination is mostly still well-maintained, but some abandoned areas are also found due to tourists or inhabitants exploitation. It can be seen from buildings layout exceeding the beach border, garbage stacking in the coastal area up to the sea, careless clear-water consumption, and unmanaged and uncontrolled waste management system. Based on these circumstances, a strategy to maintain existing natural preservation is highly required by the utilization of environmentally friendly energy. The sustainable strategy integrates hotel resort areas with its surroundings, viewed from biomimetic architecture, and contains climate, biology, architecture, and technology, collectively. The research, then, discusses how to respond to the natural condition of Tanjung Karang beach, by considering its surroundings in terms of adaptation to nature and evolution [1], and also utilizes regional climate-supported energy, optimally, such as the solar energy and heat, wind, and surroundings-sourced water. Further, the adaptation of a coastal-traditional architecture was also performed by duplicating (mimetic), a transformation was relevantly conducted. In this research, a biomimetic approach was not comprehensively done, but it was limited to a simple simulation process, consisting of site management, site analysis via environment interaction, the concept of the hotel resorts design considering traditional principles such as building style, the mass form of buildings, and a schematic and simulated management of partly renewable energy.

Differentiation of communities of macroinvertebrates and cottoid fish associated with methane seeps of different bottom landscapes of Lake Baikal

The paper presents the results of the study of communities of macroinvertebrates and cottoid fish inhabiting methane seeps of Lake Baikal. For the analysis, we used video surveillance and collection of animals carried out with the help of "Mir" deep-water submersible, as well as NIOZ-type box-corer samplers from the board of a research vessel. Posolskaya Bank and Saint Petersburg methane seeps are located in different basins (southern and middle) and at different depths (300–500 m and ~ 1400 m), characterized by the different underwater landscapes (slope of underwater upland and hills formed by gas hydrates), by the structure of gas hydrates and their depth location in sediments, as well as the composition of microbial mats and communities of microorganisms of bottom sediments. Both seeps are characterized by bubble discharge of methane gas and the formation of highly productive communities of large invertebrates and cottoid fish on seep habitats. Seep animal communities consisted of species-depleted invertebrates and fish of the surrounding deep-water benthal of the Lake. We showed the similarities and differences in the composition of the faunas of two seeps, as well as the quantitative characteristics of taxonomic groups of macroinvertebrates and cottoid fishes. Obligate species have not been revealed on the methane seep Posolskaya Bank. For the methane seep Saint Petersburg, the gastropod species Kobeltocochlea tamarae Sitnikova, Teterina et Maximova, 2021 (Caenogastropoda: Benedictiidae) was designated as an obligate species; among bottom cottoid fishes, Neocottus werestschagini (Taliev, 1953) (Cottoidei: Abyssocottidae) had possible a transitional state to obligate. We presented the data on the assimilation by seep animals of mixed photo- and chemosynthetic food with different proportions of methane-derived carbon. A hypothesis has been substantiated that deep-water seep areas could serve as refugium for the preservation of endemic fauna during the Pliocene-Pleistocene glaciations of Lake Baikal.

Beneath the surface: On the significance of the underground and underwater landscapes in selected documentaries by Werner Herzog

Werner Herzog’s films grow out of landscapes. The frames opening his works very often present landscapes whose role goes beyond illustrative or informative functions. Analyzing films such as Encounters at the End of the World, Cave of Forgotten Dreams, and Into the Inferno, the text reconstructs the meanings inscribed in Herzog’s underground and underwater landscapes. The journey beneath the surface of spaces dominated by nature usually constitutes an equivalent of the journey into culture in the director’s works. In a sense, they are films laced with reflection about experiencing landscapes. What is more, Herzog undertakes his reflections in the realm of documentary cinema, which is firmly entangled with the category of truth. Entering a landscape is therefore a way of reaching truth for the director—however, not objective but “poetic” and “ecstatic” truth, which, according to the creator, has a much more significant quality than mundane facts.

The harmonization of small-scale marine spatial protection in the Argentine Islands area (Antarctic Peninsula) under the Antarctic Treaty System

The purpose of the article is to summarize the results of field studies carried out in the framework of the State Antarctic Research Program for 2011–2020 and undertaken to identify areas of special interest for small-scale marine spatial protection in the Argentine Islands water area. The scientific results reported in the publications and relevant meetings’ documents officially presented by the Ukrainian delegation in 2012–2019 were summarized and interpreted in view of the Antarctic Treaty System (ATS) provisions on marine spatial protection. GIS analysis was applied to field data. It is shown that the development of protection regime for small-scale underwater landscape is based on systematic biogeographical data collected during seasonal and year-round Ukrainian Antarctic expeditions in 2011–2019. In order to harmonize the application of all available tools of spatial ecosystem-based protection across the ATS, it is proposed to designate the long-term environmental monitoring sites around Ukrainian Antarctic Akademik Vernadsky station as a new Antarctic Specially Protected Area (ASPA) consisting of terrestrial and marine components. It is shown that the marine component of the proposed ASPA could serve as one of the scientific reference areas of the broad-scale Marine Protected Area in Domain 1 within the Antarctic Peninsula region for assessing the impact of climate change on benthic communities, as well as breeding success and distribution of penguin colonies.

Limited effects of Sargassum horneri, an invasive alga, on temperate reef fish assemblages

Biological invasions can dramatically affect the ecology of invaded regions, and globally have resulted in economic damages that total billions of dollars annually. In recent years, an invasive alga, Sargassum horneri, has become established and spread along the coast of southern California (USA). Using field observations and a field experiment, we explored how this non-native alga influences the structure of fish assemblages on temperate reefs in southern California where S. horneri has become prolific. Fish and algal assemblages were quantified along transects on rocky reefs at depths of 3 and 6 m at 6-8 study sites spanning 5 km on 4 occasions over 1.5 yr. Spatiotemporal variation in the fish assemblage was not strongly correlated with the abundance of invasive S. horneri over this period, although it became less variable as native giant kelp Macrocystis pyrifera disappeared from the study sites due to a warm-water event, during which the invasive S. horneri became more dominant. An experiment removing a total of 4.25 t of S. horneri from 6 × 6 m plots (n = 14) revealed that the invasive alga did not affect fish abundance, species richness, species diversity (H’), or multivariate assemblage structure over a 5 mo period. Overall, we found little evidence of negative effects of S. horneri on fishes even though it drastically changed the underwater landscape. Nevertheless, we advise cautionary management actions to limit the movement of this invasive alga because its effects on other community members, such as other algal species, may be detrimental, and longer-term effects on fishes might develop.

Assessing the Utility of Open-Access Bathymetric Data for Shipwreck Detection in the United States

Investigation of submerged cultural heritage is an important area of archeological focus. However, the expense of acquiring the necessary data to conduct studies of underwater landscapes is often prohibitive to many researchers. Within the United States, highly resolved bathymetric data are openly available from governmental agencies, and yet little to no marine archaeological exploration has occurred using this information. Here, we investigate the archaeological utility of freely available bathymetric datasets from the National Oceanic and Atmospheric Administration (NOAA) in the United States. These datasets have not previously been utilized for archaeological publications, and include swath bathymetric and topographic LiDAR data, which are widely used by marine archaeologists. We present three case studies from Long Island, New York, coastal Massachusetts (on the Eastern coast of North America), and New Orleans (on the Gulf Coast of North America) to demonstrate the potential of this open-access information for locating shipwreck sites. Results indicate that shipwrecks at varying levels of preservation can be identified at depths up to 160 m, and that even in extremely turbid waters, bathymetric LiDAR can detect some wreckage. Following this assessment, we develop an automated shipwreck detection procedure using an inverse depression analysis. Our results are promising for automated detection methods in marine archaeology research. We argue that archaeologists in the United States should take advantage of these freely available data, as it is possible that these bathymetric data can be used for detection and conservation of cultural and environmental resources even without large funding acquisitions.

Principles of Bionomic Zoning of the Coastal Zone and Shelf of the World Ocean

The paper discusses the principles of developing a hierarchical system of units for zoning the coastal zone and shelf of the World Ocean based on bionomic (ecosystem) features are discussed. A number of scientific and applied problems require zoning of ecoregions (sea basins) at the regional and topological levels. A system of units is proposed, taking into account the zonal, depth-related, and azonal features of ecoregions. The main initial unit of bionomic zoning is the underwater landscape. As an example of regional and topological zoning, the morphological structure of landscapes of three districts of the Japanese coastal region of the Sakhalin orogenic region of the Japan Sea is considered. The hierarchical system of units of bionomic zoning makes it possible to identify landscape analogues. In practical terms, this zoning may help to predict the introduction of useful species and forecast the risk of invasion by harmful species.

Evidences of fishing impact on the coastal gorgonian forests inside the Portofino MPA (NW Mediterranean Sea)

The gorgonians Paramuricea clavata (Risso, 1826) and Eunicella cavolini (Koch, 1887) are important habitat-forming species within the Mediterranean coralligenous habitats, creating complex, three-dimensional forests that greatly contribute to the underwater landscape of the coastal hard grounds. Dense forests of both species are present within the Portofino Marine Protected Area (Ligurian Sea, NW Mediterranean Sea), showing a distinct bathymetric separation and site-specific differences.Quantitative evidences obtained with a monitoring census conducted in 2016 in 16 sites within the MPA support the existence of a widespread damage on these populations partially due to the mechanical injuries inflicted by recreational and professional demersal fishing gears. Considering all the studied populations, it resulted that 53% of the colonies of P. clavata and 36% of the colonies of E. cavolini were showing traces of impact, of which 10% in P. clavata and 7% in E. cavolini were due to direct entanglements with lost longlines.In the last decades, recurrent massive mortalities related to temperature anomalies and storms, have greatly reduced the gorgonian populations in this area and fishing impact severely affects survived or recovering colonies. Considering the vulnerable status of these species, and the increasing stress due to climate change, a correct management of the anthropic pressures is strongly needed to help preserving these relevant ecosystems.

Submerged aquatic vegetation cover and complexity drive crustacean zooplankton community structure in a large fluvial lake: An in situ approach

Submerged aquatic vegetation (SAV) is considered an important driver of the zooplankton community, owing to the refuge offered by its structural complexity. However, non-destructive in situ approaches to assess quantitatively the features of SAV beds and their effects on zooplankton community are still lacking. This study aims to: 1) estimate SAV cover and complexity using subaquatic upward photographs (SUP) and 2) analyse the relationship between SAV variables and crustacean zooplankton composition and functional diversity (FD). SAV biomass and zooplankton were sampled at 52 stations in a large fluvial lake. Two metrics based on SUP were used to quantify SAV cover and complexity: 1) the percentage of the underwater landscape occupied by SAV (PLAND: SAV cover), and 2) its perimeter-area fractal dimension (PAFRAC: SAV complexity). Zooplankton composition and functional diversity were estimated based on crustacean species assemblages and functional traits. We used linear models to describe the relationships between SAV indices, environmental variables and zooplankton abundance, biomass and FD. SUP was an effective method to estimate in situ SAV cover and complexity. PLAND and PAFRAC were positively related to SAV biomass and zooplankton abundance, yielding a non-destructive assessment of the SAV-zooplankton relationships. Our study partially supports the habitat complexity-ecological niche availability hypothesis, as SAV cover and complexity influenced zooplankton functional groups and diversity indices. However, water transparency and depth also had important effects in interaction with PLAND and PAFRAC, and it remains difficult to fully disentangle the effects of SAV complexity from SAV cover on crustacean zooplankton community structure.

Underwater landscapes condition assessment in the Nakhodka bay (sea of Japan) port water area

The diversity of natural resources and favorable economic and geographical location have always ensured a high degree of the coastal zone development. This is particularly pronounced in port areas, where there is not only a high concentration of production facilities, but also a high population density, leading to conflict situations and social tensions. Underwater landscapes monitoring results in the coal terminals area are presented. Contamination of bottom grounds by oil products and heavy metals has been noted. Marine bottom sediments are an active accumulator of contaminants which, when entering the marine area either independently or as a result of sorption on suspended particles of organic and mineral origin, gradually settle to the bottom. This makes them a potential source of secondary contamination of the water body. Excess of the maximum permissible concentrations for such indicators as easily oxidizing organics, phenols, petroleum products, and suspended substances in the bottom water horizon has been detected. Comparing the research results both in the bay head and at its outlet, it is necessary to note slight differences. The content of contaminating components in the tested biota samples has been found to correspond to the technical mariculture. An important parameter of the sustainable state landscape is not only the presence and diversity of biota, but also the concentration of major pollutants in it. Unstable dynamics of heavy metal concentration in hydrobiont tissues has been observed. It should be noted that the concentration of some pollutants, such as copper, chromium and cadmium, are slightly higher in biota living at the exit from the bay, than the one at the bay head. There is a change in the structure of landscape complexes: the control points are characterized by a high variety of benthos but decrease in the projective coverage by algae. The underwater landscape result analysis has showed that port facilities operating in the area under consideration have an impact on the environment corresponding to the production and technological process

Mesophotic rocks dominated by Diazona violacea: a Mediterranean codified habitat

The football ascidian Diazona violacea was observed in three different sites in the Aeolian Archipelago (Southern Tyrrhenian Sea), from 53 to 116 m depth. A large population of this ascidian was found on rocky habitat, enhancing its three-dimensionality and constituting a peculiar facies. Colonies of D. violacea showed a mean density of 0.87 ± 0.09 colonies m−2 and a maximum of 4 colonies m−2. The number of zooids was used as a proxy of colony size and age (assuming that the higher the number of zooids, the larger and older is the colony), and the population showed a leptokurtic distribution with the dominant presence of colonies with fewer than 100 zooids. Large aggregations of this species proved to play an important role in terms of seabed complexity, influencing the underwater landscape and worth of being recognized as a relevant type of biogenic habitat (although ephemeral) that can characterize mesophotic rocks in the Mediterranean Sea.

The eastern shores of the Baltic Sea in the Early Holocene according to natural and cultural relict data

Exploration of the underwater landscape in Lithuanian waters, in the eastern part of the Baltic Sea, allowed identification of trees stumps in growth position, peat sediments, and traces of people that were living in the now flooded landscape. The exploration has been concentrated on localisation of the former Early Holocene coasts. Based on new data about sediment layers of the Preboreal‒Atlantis I, palynological and dendrohronological analysis, identified vegetation species, and dating of wood and peat samples by radiocarbon methods the Baltic Sea water level dynamics during the stages Yoldia Sea‒Early Litorina Sea could be identified. There are traces of the eroded coasts of the Yoldia Sea at a depth of 39–43 m, which were also observed at depths of 44 and 47 m. During the Ancylus Lake transgression, the RF‐I lagoons and small lakes with the peat layer and the surrounding forests were submerged. The water level could have even risen to 10–9 m below present sea level. The water drop during the Ancylus Lake regression is evidenced by a peat layer dated to 9,150–8,520 cal BP, and similar radiocarbon dating of an oak stump. The changes of the species composition of trees are indicative of the noticeable climate changes during the period 11,410–7,900 cal BP. Litorina transgression is marked by a tree stump found at a depth of 14.5 m dated to 7,900–7,660 cal BP. The preference of the Early Holocene population to the coastal zone is evidenced by poles driven into the seabed (one was dated to 9,510–9,460 cal BP) that were detected at a depth of 11 m and the T‐shaped antler axes dated to the Early Neolithic, washed ashore from the Litorina Sea coastal Stone Age settlements.

Mapping the future of offshore wind farming

Offshore wind farming is a growing presence in the renewable energy landscape but these ambitious projects rely on precise assessments of the hard to observe underwater landscape they will occupy before construction can even begin.<br/>Many governments around the world are moving toward renewable energy sources to meet their countries energy demands. The reasons behind this are many, ranging from reducing emissions to the safety of nuclear reactors and waste. For countries lying on or near fault lines, such as Taiwan, the latter becomes an even greater concern. When the earth shakes nuclear power plants, in particular, are highly sensitive and susceptible pieces of infrastructure. To avoid potential catastrophe and achieve greener energy sources the current government in Taiwan is aiming to phase out nuclear power in the coming years and they have chosen wind power as the technology to replace a large portion of the energy supply.<br/> In Taiwan the plan to phase of nuclear power and replace it with wind power has one extra challenge. The plan is not to build on land, like the majority of wind turbine projects, but rather to head out to sea. Offshore wind farms (OWF) are becoming a larger part of the wind power market and European countries have mostly been the early adopters. The waters off Taiwan, in the Taiwan Strait, are attractive for offshore wind farming development due to the favourable wind patterns that occur there. This has drawn major interest from European companies and others around the world to place bids on the growing number of wind farming projects. However, before any of these projects can take place an extensive effort to understand more about the environments below the surface must first be completed.<br/>Fortunately for those individuals who are curious as to the make-up and appearance of the ocean floor, such as engineers who plan to construct permanent structures in the depths, many techniques to map the seabed have been developed. Dr Gwo-Shyh Song, from The Institute of Oceanography at The National Taiwan University, in Taipei, is one local researcher who is very familiar with these methods. "I have been working on seafloor mapping around the Taiwan Island for last 20 years," points out Song. "This includes geophysical surveys, reservoir siltation surveys, cable and pipeline route surveys using a variety of techniques like multi-beam sounders and side-scan sonar as well as chirp sub-bottom profilers." When the offshore wind farming initiative needed experienced local researchers, he was one of a few people with the prerequisite expertise and technical skill required. "In 2012, when the OWF project was set into action and promoted by the Taiwanese Government, myself and my graduated students now employed within Global Aqua Survey Ltd started to become involved with many related investigatory projects," he explains.

The First Data on the Structure of Vulnerable Marine Ecosystems of the Emperor Chain Seamounts: Indicator Taxa, Landscapes, and Biogeography

The first comprehensive study of the deep-sea ecosystems of the Emperor Chain seamounts (the northwestern Pacific Ocean) was conducted in July–August 2019 by A.V. Zhirmunsky National Scientific Center of Marine Biology, FEB RAS. The expedition, using a remote-operated underwater vehicle Comanche 18, was aimed at the study of distribution of typical underwater landscapes and key taxa of Octocorallia corals and Hexactinellida sponges in the vulnerable marine ecosystem of the seamounts. New data on the macrobenthos biodiversity and biogeographic characteristics of deep-sea corals and sponges, which are the dominant animals in the studied area, are presented. The survey has shown changes of the coral fauna in the latitudinal direction and obtained new data on the biogeographic boundary in the area of the Emperor Chain seamounts.

Landscape Beneath the Waves: the archaeological investigation of underwater landscapes

Landscape Beneath the Waves: the archaeological investigation of underwater landscapes

The Distribution of the Antarctic Limpet Nacella concinna (Nacellidae) on Underwater Landscapes of the Meek Channel, Argentine Islands, Graham Land

Objective(s). To clarify the patterns of Nacella concinna (Nacellidae) distribution in the water area of the Argentine Islands Archipelago (Meek Channel). Methods. Morphometric, statistical, cartographic methods as well as geoinformation technologies were used. Results. Analyzed the patterns of mollusc distribution on different transects, taking into account their morphometric characteristics — the length of the shell, the mollusс weight, the population density. It is determined that the distribution of Nacella concinna subpopulations does not have any visible strict regularity. At different transects with an insignificant exception the morphometric characteristics of the mollusсs are distributed both in classical and non-classical models. At the MK1 transect is shown the classical model of the distribution of morphometric characteristics, namely with an increase in the mollusс population density, the morphometric characteristics (shell length and weight of the mollusс) tend to decrease. At the MK2 transect is shown non-classical distribution model. The morphometric characteristics (shell length, mollusс weight) increase with an increase in the population density of the molluscs. At the MK3 transect is shown the classical distribution model, but a characteristic feature is an increase in the population density up to 5 m depth and a gradual decrease in the population density from 5 to 20 m. Geoinformation models of the Nacella concinna distribution by depth in the water area of the Ukrainian Antarctic Akademik Vernadsky station were constructed. Conclusions. Maps of the distribution of the Nacella concinna population were created for this region for the first time. The dimensional classes of the Nacella concinna subpopulation from selected water areas of the Argentine Islands were described.