Introducing Fiji and ICY image processing techniques in ichnological research as a tool for sedimentary basin analysis

Some features of trace fossils are not easy to determine due to limited vissibility of trace fossils. Here, we applied two image processing techniques (Fiji and ICY) to ichnological studies and we compare them with the previously used high-resolution image treatment method. , discussing their usefulness for ichnological studies. Then, these are compared with a high resolution image treatment. These techniques are revealed as rapid alternatives for estimation of some ichnological features, being so useful for the first stages of research, when a detailed analysis is not needed

Complex sublinear burrows in the deep sea may be constructed by amphipods

Trails, burrows, and other “life traces” in sediment provide important evidence for understanding ecology—both of the maker and of other users—and behavioral information often lacking in inaccessible ecosystems, such as the deep sea or those that are already extinct. Here, we report novel sublinear rows of openings in the abyssal plains of the North Pacific, and the first plausible hypothesis for a maker of these constructions. Enigmatic serial burrows have now been recorded in the Pacific and Atlantic deep sea. Based on image and specimen evidence, we propose that these Bering Sea excavations represent amphipod burrows, while the maker of the previously known Mid-Atlantic Ridge constructions remains undetermined. We propose that maerid amphipods could create the Pacific burrows by eating–digging horizontally below the surface along a nutrient-rich layer in the sediment, making the serial openings above them as they go, for conveniently removing excavated sediment as the excavation progresses. These striking structures contribute to local biodiversity, and their maker could be considered a deep-sea ecosystem engineer.publishedVersio

Small topographical variations controlling trace maker community: Combining palaeo- and neoichnological data at the Porcupine Abyssal Plain

Ichnological research has generally assumed that abyssal plains are dominated by quiescent, homogenous environmental conditions. Thus, deep-sea trace fossil assemblage changes have been usually linked to significant spatial and temporal environmental variations. Here, we conducted a comparative ichnological analysis between a small abyssal hill (50 m elevation) and the surrounding abyssal plain; this modest bathymetric variation is known to generate substantial environmental heterogeneity for the benthic fauna community of the Porcupine Abyssal Plain (c. 4850 m depth), Northeast Atlantic. Based on X-ray data from a 5 × 5 core grid emplaced in two box cores, we compared hill and plain bioturbational sedimentary structures, including trace fossil assemblages (e.g., ichnotaxonomy) and biodeformational structures (e.g., mixed-layer depth). We observed that topographically-enhanced near-bottom currents over the hill likely produce significant changes in depositional dynamics and sediment properties (e.g., grain size, organic matter content and degradation), and control specificities of bioturbational sedimentary structures (e.g., trace fossils, mixed layer attributes such as thickness, mottled background, discrete traces). Palaeoichnological data suggested that the abyssal plain had experienced consistent conditions during the last thousands of years while the abyssal hill recorded improving environmental conditions for the trace maker community. Our results highlight the complexity of the deep-sea environment, demonstrating that small changes in bioturbated sedimentary assemblages appear even within the same box core (m-scale), and that substantial changes can occur due to environmental heterogeneity (e.g., subtle topographic variations) at the local scale (km-scale). Considering the vast global extent of abyssal hill terrain, we suggest that their influence on the bioturbational sedimentary record may be significantly under-appreciated and require more attention in palaeoenvironmental reconstructions

Lebensspuren and benthic fauna diversity and density data obtained from KuramBio 2012 expedition still images (50 still images per 8 deep-sea stations)

<p>Lebensspuren and total benthic fauna diversity and density data generated by the random selection of 50 still images per station of the KuramBio 2012 expedition (Stations 3-6, 8-11; the depth of the stations ranged from 4,868 m to 5,768 m). Annotation and data reports were conducted with BIIGLE 2.0. Still images belong to videos where the Ocean Floor Observation System (OFOS) was deployed. For more information see the cruise report (RV Sonne cruise SO223; doi:10.1016/j.dsr2.2014.11.001) and Miguez-Salas et al., (2023).</p><p> </p&gt

KuramBio 2012_Lebensspuren area data

Lebensspuren data genrated by the random selection of 50 frames per station of the KuramBio 2012 expedition (8 stations analyzed; the depth of the stations ranged from 4,868 m to 5,768 m). In these 400 frames, the area of 5,692 lebensspuren was measured and the lebensspuren were classified. Additionally, megabenthic fauna was quantified and classified as “faunal coverage” at each station, which was the area covered by all individual megabenthic organisms. This “faunal coverage” area is based on the measurements of 4,009 individual animals.The research was funded by a Humboldt Postdoctoral Fellowship from the Humboldt Foundation

Still images from the KuramBio expedition 2012 (Stations 3-6, 8-11) obtained with the Ocean Floor Observation System

<p>Repository with still images obtained from the videos of the KuramBio 2012 expedition in 5 second intervals. Still images belong to deep-sea stations where the Ocean Floor Observation System (OFOS) was deployed and enough video survey was obtained (i.e., Stations 3-6, 8-11). The Station 7 survey length was enough but has no HD video. Thus, images were not retrieved since the quality does not allow accurate lebensspuren or benthic fauna identification. </p><p>The OFOS was lowered into the water at the CTD position. The first 300 meters lowering was conducted with 0.5 m/sec, and then the speed was increased to 0.8 m/sec while the ship was kept in position. At 500 meters above ground the speed was reduced to 0.5 m/sec, and further reduced to 0.3 m/sec at 200 meters above ground. As soon as visual contact with the bottom was established, the winch was stopped. The ship started moving with 0.5 knots in the appropriate direction, which was chosen depending on current and wind situation at the according station. The OFOS was kept in an appropriate distance to the seafloor, enabling the scientists to watch the macrofaunal organisms. The approximate size of the observed animals could be calculated with the help of two laser pointers having a distance of 10 cm between each other (see Fig. 1-3). Generally, the survey lasted slightly over one hour, then the ship was stopped and heaving of the OFOS started. This was first conducted at 0.5 m/sec and accelerated to 1.0 m/sec. For more information see the cruise report (RV Sonne cruise SO223; doi:10.1016/j.dsr2.2014.11.001).</p&gt

Neoichnological analysis of sea stars in the deep sea near the Aleutian Trench: behavioral insights from in situ observations

Abstract The study of biogenic structures (e.g. lebensspuren) produced by benthic fauna on the seafloor provides invaluable information about the behavior of their tracemakers. In the case of sea stars, most of the previous research has been focused on shallow-marine environments due to the extreme scarcity of data from deep-sea lebensspurens. Here, we examined sea star traces from six deep-sea stations (deeper than 4500 m) near the Aleutian Trench (North Pacific). A total of six families were identified from still images. The majority of them were not observed producing any lebensspuren or just pentameral impressions related to resting and feeding activities. Two members of the families Pterasteridae and Porcellanasteridae could be clearly characterized by a composite behavior resulting in contrasting lebensspuren morphotypes. A morphotype belonging to the genus Hymenaster undet .produced pentameral impressions (related to predation) and punctuated trails (related to podia locomotion). Members of the family Porcellanasteridae produced oval to circular impressions (that may be related to burrowing trails for the detection of organic matter), flat-shallow trails (related to podia locomotion), and irregular M-ridged trails (related to locomotion while feeding through the sediment interface). There is a severe scarcity of data related to the locomotion of past deep-sea Asteroidea (i.e. trace fossils) and their ichnotaxonomical classification. We discuss the implications of our results for the ichnofamily Biformitidae, as well as the importance of considering other features (e.g. podia impressions) rather than just hook-shaped traces related to arm locomotion.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Diversity and density relationships between lebensspuren and tracemaking organisms: a study case from abyssal northwest Pacific

<jats:p>Abstract. In the deep sea, interactions between benthic fauna and seafloor sediment primarily occur through bioturbation that can be preserved as traces (i.e. lebensspuren). Lebensspuren are common features of deep-sea landscapes and are more abundant than the organisms that produce them (i.e. tracemakers), rendering lebensspuren promising proxies for inferring biodiversity. The density and diversity relationships between lebensspuren and benthic fauna remain unclear, and contradicting correlations have been proposed (i.e. negative, positive, or even null correlations). To approach these variable correlations, lebensspuren and benthic fauna were characterized taxonomically at eight deep-sea stations in the Kuril-Kamchatka Trench area, together with two novel categories: tracemakers (specific epibenthic fauna that produce these traces) and degrading fauna (benthic fauna that can erase lebensspuren). No general correlation (overall study area) was observed between diversities of lebensspuren, tracemakers, degrading fauna, and fauna. However, a diversity correlation was observed at specific stations, showing both negative and positive correlations depending on: (1) the number of unknown tracemakers (especially significant for dwelling lebensspuren); (2) the lebensspuren with multiple origins; and (3) tracemakers that can produce different lebensspuren. Lebensspuren and faunal density were not correlated. However, lebensspuren density was either positively or negatively correlated with tracemaker densities, depending on the lebensspuren morphotypes. A positive correlation was observed for resting lebensspuren (e.g. ophiuroid impressions, Actiniaria circular impressions), while negative correlations were observed for locomotion-feeding lebensspuren (e.g. echinoid trails). In conclusion, lebensspuren diversity may be a good proxy for tracemaker biodiversity when the lebensspuren–tracemaker relationship can be reliable characterized. Lebensspuren–density correlations vary depending on the specific lebensspuren residence time, tracemaker density, and associated behaviour (rate of movement). Overall, we suggest that lebensspuren density and diversity correlations should be studied with tracemakers rather than with general benthic fauna. On a global scale, abiotic (e.g. hydrodynamics, substrate consistency) and other biotic factors (e.g. microbial degradation) may also play an important role. </jats:p&gt