المؤلفون: Feldens, Peter, Held, Philipp, Otero-Ferrer, Francisco, Bramanti, Lorenzo, Espino, Fernando, Schneider von Deimling, Jens

المصدر: http://lobid.org/resources/99370951344706441Test#!, 4:988366.

مصطلحات موضوعية: multibeam echo sounders, marine animal forests, habitat mapping, Lanzarote, multi-detect, Anthipatella wollastoni

الوصف: The black coral Anthipatella wollastoni forms marine animal forests in the mesophotic zone. The spatial extent of black coral forests is not well known in many regions. Due to its protein and chitin skeleton, the coral is difficult to image using acoustic remote sensing techniques compared to corals with carbonate skeletons. Several manufacturers have recently introduced an additional data type to their multibeam echosounders, called “multi-detection,” which provides additional target detections per beam in addition to the primary bottom detection. In this study, we used a Norbit chirp multibeam echosounder in multi-detect mode to acquire up to three targets in each beam in an area of black coral below 45 m depth off the coast of Lanzarote (Canary Islands, Spain). Multi-detect allows features above and below the primary bottom detection to be identified without the need to store and process water-column data. Black coral can be detected by comparing “multi-detection” data with ground truthing by technical divers and underwater cameras. However, the repeatability of the detections is limited and further sensitivity studies are required.

العلاقة: https://repository.publisso.de/resource/frl:6475445Test; https://doi.org/10.3389/frsen.2023.988366Test; https://www.frontiersin.org/articles/10.3389/frsen.2023.988366/full#h12Test

الإتاحة: https://doi.org/10.3389/frsen.2023.988366Test
https://repository.publisso.de/resource/frl:6475445Test

المؤلفون: Czymzik, Markus, Tjallingii, Rik, Plessen, Birgit, Feldens, Peter, Theuerkauf, Martin, Moros, Matthias, Schwab, Markus J., Nantke, Carla K. M., Pinkerneil, Silvia, Brauer, Achim, Arz, Helge W.

المصدر: http://lobid.org/resources/990143550400206441Test#!, 19(1):233-248.

الوصف: Knowledge about the timing, amplitude and spa- tial gradients of Holocene environmental variability in the circum-Baltic region is key to understanding its responses to ongoing climate change. Based on a multi-dating and proxy approach, we reconstruct changes in productivity us- ing total organic carbon (TOC) contents in sediments of Lake Kälksjön (KKJ) from west–central Sweden spanning the last 9612 ( + 255/ − 114) years. An exception is the period from 1878 CE until today, in which sedimentation was dominated by anthropogenic lake level lowering and land use. In-lake productivity was higher during periods of warmer winters with shortened ice cover and prolonged growing seasons. A multi-millennial increase in productivity throughout the last ∼ 9600 years is associated with progressively warmer winters in northwestern Europe, likely triggered by the co- inciding increase in Northern Hemisphere winter insolation. Decadal to centennial periods of higher productivity in KKJ tend to correspond to warmer winters during a more pos- itive North Atlantic Oscillation (NAO) polarity, as recon- structed for the last 8000 years. In consequence, we assume our decadal to centennial productivity record from KKJ sedi- ments for the complete ∼ 9600 years to provide a qualitative record of NAO polarity. A shift towards higher productivity variability at ∼ 5450 cal a BP is hypothesized to reflect a re- inforcement of NAO-like atmospheric circulation variability, possibly driven by more vigorous changes in North Atlantic deep-water formation.

العلاقة: https://repository.publisso.de/resource/frl:6475435Test; https://doi.org/10.5194/cp-19-233-2023Test

الإتاحة: https://doi.org/10.5194/cp-19-233-2023Test
https://repository.publisso.de/resource/frl:6475435Test

المؤلفون: Böttner, Christoph, Stevenson, Christopher, Englert, Rebecca, Schӧnke, Mischa, Geersen, Jacob, Pandolpho, Bruna, Feldens, Peter, Krastel, Sebastian

الوصف: Submarine gravity flows are ubiquitous across the seafloor, occurring in all sizes and are the primary mechanism for transporting sediment from the shelf to the deep ocean. Giant flows are an enigmatic phenomenon because they often do not originate from an appropriately large landslide. Theoretical arguments propose that giant events can ignite from much smaller flows. However, quantifying how much a flow can enlarge is problematic due to their extreme size. Here, we reconstruct the properties and evolution of a giant gravity flow by mapping its traces from source to sink. The initial failure (~ 0.8 km 3 ) entrained ~ 200 times its starting volume: catastrophically evolving into a giant flow with a total volume of ~ 162 km 3 with estimated flow speeds between 15–30 m/s, and a run-out of ~ 2000 km. The entrainment of mud was the critical fuel for ignition, which promoted run-away flow growth and extreme levels of erosion.

وصف الملف: text

العلاقة: https://oceanrep.geomar.de/id/eprint/59620/1/bf4e2dcb-28ae-4be3-ac57-1599f0a5d874.pdfTest; Böttner, C., Stevenson, C., Englert, R., Schӧnke, M., Geersen, J., Pandolpho, B., Feldens, P. and Krastel, S. (Submitted) The ignition and evolution of a giant submarine gravity flow. Open Access Research Square preprint deposition service . DOI 10.21203/rs.3.rs-3705964/v1 .

الإتاحة: https://doi.org/10.21203/rs.3.rs-3705964%2Fv1Test
https://doi.org/10.21203/rs.3.rs-3705964/v1Test
https://oceanrep.geomar.de/id/eprint/59620Test/
https://oceanrep.geomar.de/id/eprint/59620/1/bf4e2dcb-28ae-4be3-ac57-1599f0a5d874.pdfTest

المؤلفون: Feldens, Agata, Marx, Denise, Herbst, Anne, Darr, Alexander, Papenmeier, Svenja, Hinz, Matthias, Zettler, Michael L., Feldens, Peter

المصدر: Frontiers in Earth Science ; volume 11 ; ISSN 2296-6463

مصطلحات موضوعية: General Earth and Planetary Sciences

الوصف: This study contributes to a better understanding of geogenic reef distribution in the southern Baltic Sea and highlights the implications of survey-related factors on automated boulder classification when utilizing data from multiple surveys. The distribution of hard grounds and reefs is needed as a baseline for geological and biological studies, but also for offshore construction, navigation and coastal management. In this study we provide maps of the distribution of geogenic reefs for about 750 km 2 in the southern Baltic Sea, at the sites Wismar Bay, Darss Sill and Plantagenet Ground. The maps are based on full-coverage backscatter surveys with different side scan sonar and multibeam echo sounder systems. The distribution and number of boulders in the backscatter maps was determined using a convolutional neural network combined with quality control by human experts. The extent of the geogenic reefs was calculated on the basis of the number of boulders in 50 m x 50 m grid cells. We compare the results with previous reef maps based on point sampling, which show reefs of either biogenic or geogenic origin. According to the earlier maps, 11% of the Plantagenet Ground seabed was classified as reef habitat type. This is similar to the result of our study (12%), although we only considered reefs of geogenic origin. In the Darss Sill, geogenic reefs are larger in this study than in previous maps (30% versus 23%). In both regions, the spatial distribution of reefs differs significantly between old and new maps. For Wismar Bay, previous maps classify 3% of the seafloor as habitat type reef, whereas this study classifies 35% as geogenic reef. The use of automated classification during seafloor mapping allowed large areas to be interpreted in a few days. It also provided more information on the distribution of boulders within the geogenic reef. However, the boulder distribution maps show the negative effects of survey geometry, frequency and environmental conditions on automated boulder classification when data from ...

الإتاحة: https://doi.org/10.3389/feart.2023.1155765Test

المؤلفون: Garone, Rosa Virginia, L0nmo, Tor Inge Birkenes, Schimel, Alexandre Carmelo Gregory, Diesing, Markus, Thorsnes, Terje, L0vstakken, Lasse, Feldens, Peter, Sakellariou, Dimitris

المصدر: Frontiers in Earth Science; 2024, p1-17, 17p

مصطلحات موضوعية: DEEP learning, OCEANOGRAPHIC maps, SUBMARINE geology, CLASSIFICATION, MARINE resources, OCEAN bottom

مستخلص: The accurate mapping of seafloor substrate types plays a major role in understanding the distribution of benthic marine communities and planning a sustainable exploitation of marine resources. Traditionally, this activity has relied on the efforts of marine geology experts, who accomplish it manually by examining information from acoustic data along with the available ground- truth samples. However, this approach is challenging and time-consuming. Hence, it is important to explore automatic methods to replace this manual process. In this study, we investigated the potential of deep learning (U-Net) for classifying the seabed as either "bedrock" or "non-bedrock" using bathymetry and/or backscatter data, acquired with multibeam echosounders (MBES). Slope and hillshade data, derived from the bathymetry, were also included in the experiment. Several U-Net models, taking as input either one of these datasets or a combination of them, were trained using an expert delineated map as reference. The analysis revealed that U-Net has the ability to map bedrock and non-bedrock areas reliably. On our test set, the models using either bathymetry or slope data showed the highest performance metrics and the best visual match with the reference map. We also observed that they often identified topographically rough features as bedrock, which were not interpreted as such by the human expert. While such discrepancy would typically be considered an error of the model, the scale of the expert annotations as well as the different methods used by the experts to manually generate maps must be considered when evaluating the predictions quality. While encouraging results were obtained here, further research is necessary to explore the potential of deep learning in mapping other seabed types and evaluating the models' generalization capabilities on similar datasets but different geographical locations. [ABSTRACT FROM AUTHOR]

: Copyright of Frontiers in Earth Science is the property of Frontiers Media S.A. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Geersen, Jacob, Bradtmöller, Marcel, von Deimling, Jens Schneider, Feldens, Peter, Auer, Jens, Held, Philipp, Lohrberg, Arne, Supka, Ruth, Hoffmann, Jasper Justus Lutz, Eriksen, Berit Valentin, Rabbel, Wolfgang, Karlsen, Hans-Jörg, Krastel, Sebastian, Brandt, David, Heuskin, David, Lübke, Harald

المصدر: Proceedings of the National Academy of Sciences of the United States of America; 2/20/2024, Vol. 121 Issue 8, p1-11, 11p

مصطلحات موضوعية: STONE Age, YOUNGER Dryas, REINDEER, ICE sheets, WATER depth

مصطلحات جغرافية: MECKLENBURG (Germany : Region)

مستخلص: The Baltic Sea basins, some of which only submerged in the mid-Holocene, preserve Stone Age structures that did not survive on land. Yet, the discovery of these features is challenging and requires cross-disciplinary approaches between archeology and marine geosciences. Here, we combine shipborne and autonomousunderwater vehicle hydroacoustic data with up to a centimeter range resolution, sedimentological samples, and optical images to explore a Stone Age megastructure located in 21 m water depth in the Bay of Mecklenburg, Germany. The structure is made of 1,673 individual stones which are usually less than 1 m in height, placed side by side over a distance of 971 m in a way that argues against a natural origin by glacial transport or ice push ridges. Running adjacent to the sunken shoreline of a paleolake (or bog), whose youngest phase was dated to 9,143 ±36 ka B.P., the stonewall was likely used for hunting the Eurasian reindeer (Rangifer tarandus) during the Younger Dryas or early Pre-Boreal. It was built by hunter-gatherer groups that roamed the region after the retreat of the Weichselian Ice Sheet. Comparable Stone Age megastructures have become known worldwide in recent times but are almost unknown in Europe. The site represents one of the oldest documented man-made hunting structures on Earth, and ranges among the largest known Stone Age structure in Europe. It will become important for understanding subsistence strategies, mobility patterns, and inspire discussions concerning the territorial development in the Western Baltic Sea region. [ABSTRACT FROM AUTHOR]

: Copyright of Proceedings of the National Academy of Sciences of the United States of America is the property of National Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Papenmeier, Svenja, Darr, Alexander, Feldens, Peter

المصدر: Data, 7(5):63

مصطلحات موضوعية: Fehmarn Belt, ground mines, detonation crater, multibeam echosounder, Baltic Sea

الوصف: Military munitions from World War I and II dumped at the seafloor are a threat to the marine environment and its users. Decades of saltwater exposure make the explosives fragile and difficult to dispose of. If required, the munition is blast-in-place. In August 2019, 42 ground mines were detonated in a controlled manner underwater during a NATO maneuver in the German Natura2000 Special Area of Conservation Fehmarn Belt, the Baltic Sea. In June 2020, four detonation craters were investigated with a multibeam echosounder for the first time. This dataset is represented here as maps of bathymetry, slope angle, and height difference to the surrounding. The circular craters were still clearly visible a year after the detonation. The diameter and depth of the structures were between 7.5–12.6 m and 0.7–2.2 m, respectively. In total, about 321 m2 of the seafloor was destroyed along the track line.

العلاقة: https://repository.publisso.de/resource/frl:6441151Test; https://doi.org/10.3390/data7050063Test; https://doi.org/10.5281/zenodo.6374951Test

الإتاحة: https://doi.org/10.3390/data7050063Test
https://doi.org/10.5281/zenodo.6374951Test
https://repository.publisso.de/resource/frl:6441151Test

المؤلفون: Theuerkauf, Martin, Blume, Theresa, Brauer, Achim, Dräger, Nadine, Feldens, Peter, Kaiser, Knut, Kappler, Christoph, Kästner, Frederike, Lorenz, Sebastian, Schmidt, Jens‐Peter, Schult, Manuela

الوصف: Lake‐level reconstructions are a key tool in hydro‐climate reconstructions, based on the assumption that lake‐level changes primarily reflect climatic changes. Although it is known that land cover changes can affect evapotranspiration and groundwater formation, this factor commonly receives little attention in the interpretation of past lake‐level changes. To address this issue in more detail, we explore the effects of land cover change on Holocene lake‐level fluctuations in Lake Tiefer See in the lowlands of northeastern Germany. We reconstruct lake‐level changes based on the analysis of 28 sediment records from different water depths and from the shore. We compare the results with land cover changes inferred from pollen data. We also apply hydrological modelling to quantify effects of land cover change on evapotranspiration and the lake level. Our reconstruction shows an overall lake‐level amplitude of about 10 m during the Holocene, with the highest fluctuations during the Early and Late Holocene. Only smaller fluctuations during the Middle Holocene can unambiguously be attributed to climatic fluctuations because the land cover was stable during that period. Fluctuations during the Early and Late Holocene are at least partly related to changes in natural and anthropogenic land cover. For several intervals the reconstructed lake‐level changes agree well with variations in modelled groundwater recharge inferred from land cover changes. In general, the observed amplitudes of lake‐level fluctuations are larger than expected from climatic changes alone and thus underline that land cover changes in lake catchments must be considered in climatic interpretations of past lake‐level fluctuations.

وصف الملف: application/pdf

العلاقة: https://epub.ub.uni-greifswald.de/frontdoor/index/index/docId/6303Test; urn:nbn:de:gbv:9-opus-63035; https://nbn-resolving.org/urn:nbn:de:gbv:9-opus-63035Test; https://doi.org/10.1111/bor.12561Test; https://epub.ub.uni-greifswald.de/files/6303/BOR_BOR12561.pdfTest

الإتاحة: https://doi.org/10.1111/bor.12561Test
https://epub.ub.uni-greifswald.de/frontdoor/index/index/docId/6303Test
https://nbn-resolving.org/urn:nbn:de:gbv:9-opus-63035Test
https://epub.ub.uni-greifswald.de/files/6303/BOR_BOR12561.pdfTest

المؤلفون: Schulze, Inken, Gogina, Mayya, Schönke, Mischa, Zettler, Michael L., Feldens, Peter

المصدر: Frontiers in Remote Sensing ; volume 3 ; ISSN 2673-6187

الوصف: This study investigated the seasonality of acoustic backscatter intensities, exploring three habitats in the southwestern Baltic Sea: 1) a mussel-covered reef, 2) coarse sand and gravel, and 3) seagrass meadows. Backscatter information of different, partly calibrated frequencies (200, 400, 550, and 700 kHz) was collected in three seasons (May, August, and October). The acoustic data were supported by point samples and video profiles for grain size and benthic community analysis. Angular response curves helped to quantify the seasonal backscatter response of the different frequencies. The multifrequency and multiseasonal backscatter maps distinguish the three habitats and reveal variable seasonal differences in acoustic backscatter, but not all changes in the benthic community can be recognized in the acoustic data. 1) The high-backscatter response of the mussel-covered reef shows little seasonal differences and was frequency independent. 2) The ecologically valuable coarse sand and gravel areas show small-scale seasonal alterations in the sediment composition and morphology, mainly caused by changes in local hydrodynamics. Higher frequencies were found best suited to identify coarse sand and gravel. 3) Seagrass meadows seasonality is dominated by growth of seagrass blades, increasing the backscatter response compared to bare sand. The use of multiple frequencies is beneficial as the low frequency is sensitive to changes in the shallow subsurface and benthic features such as seagrass rhizomes, while the higher frequency highlights changes related to coarser sediment.

الإتاحة: https://doi.org/10.3389/frsen.2022.956994Test

المؤلفون: Marx, Denise, Feldens, Agata, Papenmeier, Svenja, Feldens, Peter, Darr, Alexander, Zettler, Michael L., Heinicke, Kathrin

المصدر: Biology (2079-7737); Jan2024, Vol. 13 Issue 1, p6, 32p

مصطلحات موضوعية: OCEAN zoning, NATURE reserves, MARINE biodiversity, OCEANOGRAPHIC maps, HABITATS, UNDERWATER cameras, OCEAN bottom

الشركة/الكيان: EUROPEAN Commission

مستخلص: Simple Summary: This study provides full-coverage maps of the habitats and biotopes in the German Baltic Sea at an unprecedented level of resolution. We combined geological and biological surveys to map the seabed and collected extensive data to classify different habitats and their inhabitants. Using newly established national guidelines and modelling, we produced highly accurate maps. These maps are of practical use in meeting national and regional reporting requirements, facilitating management decisions, supporting marine spatial planning, and answering research questions. To maintain or enhance biodiversity and sea floor integrity, mapping benthic habitats is a mandatory requirement in compliance with the Marine Strategy Framework Directive (MSFD). The EU Commission Decision distinguishes between Broad Habitat Types (BHTs) and Other Habitat Types (OHTs). At the regional level, biotopes in the Baltic Sea region are classified according to the HELCOM underwater biotope and habitat classification (HUB). In this study, the habitats and their benthic communities were mapped for the entire German Baltic Sea at a high spatial resolution of 1 km. In two nature conservation areas of the Exclusive Economic Zone (EEZ) as well as selected focus areas in the coastal waters, the resolution we provide is even more detailed at 50 × 50 m. Hydroacoustic data recording and benthological surveys (using bottom grabs, underwater towing camera technology, and diver sampling) helped identify biotopes in high resolution. Based on these data, together with additional data acquired since 2010 (a total of over 7000 stations and transect sections), we were able to spatially delineate benthic biotopes and their communities via predictive habitat modelling. The results are provided as full-coverage maps each for BHT, OHT, and HUB (9 classes of BHTs, 5 classes of OHTs, and 84 classes of HUB) with a level of spatial detail that does not yet exist for the Baltic Sea, and they form an essential basis for future monitoring, status assessments, and protection and management measures. [ABSTRACT FROM AUTHOR]

: Copyright of Biology (2079-7737) is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)