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Deep-sea environment, characterized by high pressures, extremely high/low temperatures, limited photosynthesis-generated organic matter, darkness, and high levels of corrosion, is home to flourishing special ecosystems in the world. Here, we illustrate how the deep-sea equipment offers insights into the study of life in the deep sea based on the wo...
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... activities, and climate change, the conservation of deep-sea biodiversity and ecosystems has become an international agenda. Currently, some typical deepsea ecosystems, such as hydrothermal vents [6][7][8], cold seeps [9,10], whale falls [11,12], seamounts [13,14], and oceanic trenches, have been discovered in the deep-sea area [15,16] ( Fig. 1). How these hidden communities were and will be impacted by anthropologic behaviors or natural environment changes await to be clarified, especially, what kind of technologies can help to address such problems necessitates ...
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... In recent years, with huge requirements in scientific investigation, energy resource exploitation, and national defense in the deep ocean, great progress has been achieved in the field of deep-sea technology [14][15][16]. Several major national deep-sea equipment have been established, such as submarines, deep-diving submersible vehicles, deepwater oil or gas wells, and so on [17][18][19][20]. Previous studies have shown that with the increase of hydrostatic pressure, cavitation can contribute to a higher local temperature and pressure during bubble collapsing [21]. ...
... Two driving forces have fueled this augmentation: an 'organic' growth linked to taxonomic changes triggered by the rise of molecular phylogenies (e.g., elevation of subgenera to genera level, splitting of genera to avoid paraphyly, and so on), and a 'methodological' growth linked to the discovery of new luminescent species (or to the discovery of the luminescence competence of species discovered before). In the coming decades, however, we expect the latter to be the main vector of luminescent animal genera increase since (i) many taxonomic groups have now undergone molecular-enabled taxonomic changes and, hence, might have reached relative taxonomic stability, and (ii) the development of deep-sea exploration technologies and light measurement techniques will likely fuel the detection of new luminescent animals, facilitating the in situ observation of luminescent behaviors and the collection of animals in good physiological conditions for laboratory experimentation [18,19,[86][87][88][89]. ...
Bioluminescence is the production of visible light by an organism. This phenomenon is particularly widespread in marine animals, especially in the deep sea. While the luminescent status of numerous marine animals has been recently clarified thanks to advancements in deep-sea exploration technologies and phylogenetics, that of others has become more obscure due to dramatic changes in systematics (themselves triggered by molecular phylogenies). Here, we combined a comprehensive literature review with unpublished data to establish a catalogue of marine luminescent animals. Inventoried animals were identified to species level in over 97% of the cases and were associated with a score reflecting the robustness of their luminescence record. While luminescence capability has been established in 695 genera of marine animals, luminescence reports from 99 additional genera need further confirmation. Altogether, these luminescent and potentially luminescent genera encompass 9405 species, of which 2781 are luminescent, 136 are potentially luminescent (e.g., suggested luminescence in those species needs further confirmation), 99 are non-luminescent, and 6389 have an unknown luminescent status. Comparative analyses reveal new insights into the occurrence of luminescence among marine animal groups and highlight promising research areas. This work will provide a solid foundation for future studies related to the field of marine bioluminescence.
... Besides, bioreactors have recently been used to realize methane biofiltration based on the AOM process. In the last few years, scientists have used high-pressure bioreactors to simulate deep-sea environments and explore the AOM reaction rates due to the development of deep-sea technologies [27,28]. However, the pure culture of ANME is still not available around the world due to the challenge of its slow growth rate (doubling time 2-7 months) [19]. ...
Controlling methane emission sources is important for the sustainable application of energy from the deep sea to alleviate methane-induced global warming. The anaerobic oxidation of methane (AOM) process coupled with sulfate reduction (SR) plays a key role in seafloor methane biofiltration. However, the mechanisms for the enhancement of the methane abatement efficiency in an AOM reaction system and the responses of temperature and sulfate concentration remain known. To cover the knowledge gap, this study investigated the enhancement of methane abatement in a self-manufactured AOMB system for 230 days via increasing temperatures and sulfate concentrations. The primary conclusions are as follows: (a) AOM and SR rates were significantly elevated at the conditions of temperature increase (8 to 15°C) and sulfate addition (+15 mM). (b) Sulfate and temperature were key factors influencing the diversity of archaea and bacterial communities. (c) ANME-2c, ANME-1b, SEEP-SRB1, and Halodesulfovibrio were dominant genera of methane-sulfur cycling in the system. (d) Functional gene prediction revealed that the coupling of methane oxidation and dissimilatory sulfate reduction was responsible for the methane abatement. Our findings provide new insights into the enhancement of methane abatement efficiency in the deep sea and the application of AOM reaction systems.
... At this depth, there is extremely high pressure and challenging environmental conditions. Nevertheless, some giant squids have managed to adapt to these harsh conditions and thrive in these deep-sea regions [3]. ...
The giant squid is an exceptionally intriguing organism with unique features, residing in the depths of the ocean at a depth of 1.5 km. To survive in these dark, high-pressure conditions and evade predators, this giant creature requires specific adaptations in its anatomy and way of life. The anatomy and physiology of the giant squid have inspired engineering and medical topics in human life. In this study, we will explore the potential applications of its defense system, digestion, nervous system, respiration, blood circulation, reproduction, and especially its skin in solving biotechnological challenges. Keywords: giant squid, defense system, digestion, nervous system, blood circulation, respiration, reproduction, skin, nature-inspired, biotechnology
... Seamounts, primarily formed by dormant volcanoes, have attracted considerable interest in marine biodiversity research. They are esteemed for their distinct biological communities, rich biodiversity, and significant resource potential [3], [4]. With unique underwater landscapes marked by high peaks and deep valleys, seamounts exhibit greater productivity, biomass, and biodiversity than other marine environments. ...
... 3) Changes in target scale arise from the movement of biological entities and ROVs. 4) Obscuration of objects occurs due to physical factors such as deep-sea topography, hot springs, and cold liquids. 5) Creatures' movement and camouflage characteristics can also result in blurry and challenging-to-identify images. ...
The detection and preservation of marine biodiversity has garnered global attention. The incorporation of deep learning methodologies can elevate the efficiency of species detection. In this study, we developed a DeepSeaNet for effective localization and accurate classification of organisms based on deep-sea images, as well as for hinting at unknown organisms (new species). The DeepSeaNet fully accommodates the unique characteristics of deep-sea organisms and imaging environment, leading to remarkable advancements in fine-grained analysis and accuracy. The DeepSeaNet comprises two network components: a deep-sea Classes Detection Network (CDN) and an unsupervised Species Clustering Network (SCN). CDN is used for biological class detection and is specifically tailored for deep-sea environments. It incorporates modules for feature fusion, multi-scale analysis, and self-attention. SCN is specifically designed to detect and identify new species by utilizing the location information extracted from the CDN output results. It is composed of a feature extraction module and a clustering module. By collecting deep-sea image data from the “KeXue” Science Research Vessel, we constructed a dataset totaling 29,436 images of deep-sea organisms covering more than 500 species of deep-sea seamount organisms. This dataset serves as the foundational dataset for our experiment. As a result, our model achieves an 82.18% mean average precision for class detection and a 43.4% accuracy for species detection. Furthermore, the model has the capability to identify new species through the computation of inter-species distances.
... Deep-sea biodiversity is mostly unknown due to the extreme environmental conditions that limits sampling capabilities (Rogers et al. 2015;Sinniger et al. 2016;Woodall et al. 2018). Along with advances in exploration technologies (Feng et al. 2022), new molecular technologies such as high-throughput sequencing and the molecular identification of multiple species in environmental DNA (eDNA metabarcoding; Taberlet et al. 2012) have boosted deep-sea biodiversity assessments (Guardi-ola et al. 2016;Everett and Park 2018). However, the low number of reference sequences taxonomically validated in online repository databases (e.g. ...
The giant deep-sea oyster Neopycnodonte zibrowii Gofas, C. Salas & Taviani, 2009 is a keystone deep-sea habitat builder species. Discovered about fifteen years ago in the Azores, it has been described and assigned to the genus Neopycnodonte Fischer von Waldheim, 1835 based on morphological features. In this study, we generated DNA sequence data for both mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) markers based on the holotype specimen of N. zibrowii to establish a molecular phylogenetic framework for the systematic assessment of this species and to provide a reliable (i.e., holotype-based) reference sequence set for multilocus DNA barcoding approaches. Molecular data provide compelling evidence that the giant deep-sea oyster is a distinct species , rather than a deep-water ecophenotype of Neopycnodonte cochlear (Poli, 1795), with extremely high genetic divergence from any other gryphaeid. Multilocus phylogenetic analyses place the giant deep-sea oyster within the clade "Neopycnodonte/Pycnodon-te" with closer affinity to N. cochlear rather than to P. taniguchii Hayami & Kase, 1992, thus supporting its assignment to the genus Neopycnodonte. Relationships within this clade are not well supported because mitochondrial variation is inflated by saturation that eroded phylogenetic signal, implying an old split between taxa within this clade. Finally, the set of reference barcode sequences of N. zibrowii generated in this study will be useful for a wide plethora of barcoding applications in deep-sea biodiversity surveys. Molecular validation of recent records of deep-sea oysters from the Atlantic Ocean and the Mediterranean Sea will be crucial to clarify the distribution of N. zibrowii and assess the phenotypic variation and ecology of this enigmatic species.
... In general, the inclusion of biological data and community-level information collected by different sampling methods could greatly increase the accuracy of ecosystem delineation (Costello 2009;Karenyi 2014). However, biological surveys and the collection of such data are expensive, particularly with increasing depth (Brandt et al. 2016;Feng et al. 2022), limiting the biological information available to inform the marine ecosystem map. Deep-sea habitats are a prime example here; research in this field is in its infancy in South Africa, with most work that is deeper than 200 m focused on supporting fisheries management (Griffiths et al. 2010;Atkinson et al. 2011;Lange and Griffiths 2014). ...
... Additionally, members associated with Thaumarchaeota play key roles between modules. With the development of innovative deep-sea technologies, more advancing researches on deep-sea organisms will be published (Fan et al., 2021;Feng et al., 2022). In the further, more works will focus on functional shifts of local microbes across oceanographic zonation to further develop benefit potential resources in trench sediment ecosystems. ...
Abyssal and hadal sediments represent two of the most type ecosystems on Earth and have the potential interactions
with geochemistry. However, little is known about the prokaryotic community assembly and the
response of prokaryotic communities to metal(loid)s in trench sediments due to the lack of adequate and
appropriate samples. In this study, a systematic investigation combined the assembly mechanisms and cooccurrence
patterns of prokaryotic communities between the hadal and abyssal sediments across the Yap
Trench. The results revealed that the hadal prokaryotes had less species diversity, but more abundant function
than the abyssal prokaryotes. The prokaryotic communities in the abyssal sediments had more core taxa than the
hadal sediments. Twenty-one biomarkers mostly affiliated with Nitrosopumilaceae were detected using Random-
Forests machine learning algorithm. Furthermore, stochasticity was dominant in the prokaryotic community
assembly processes of the Yap Trench sediments. Meanwhile, homogeneous selection (32.6%–52.9%) belonging
to deterministic processes governed the prokaryotic community assembly in hadal sediments with increasing of
sediment depth. In addition to total nitrogen and total organic carbon, more metal(loid)s were significantly
correlated with the prokaryotic community in the hadal sediments than that in the abyssal sediments. The hadal
prokaryotic communities was most positively related to bismuth (r = 0.31, p < 0.01), followed by calcium,
chromium, cerium, potassium, plumbum, scandium, titanium, and vanadium. Finally, co-occurrence networks
revealed two potential dominant prokaryotic modules in Yap Trench sediments covaried across oceanographic
zonation. By contrast, the hadal network had relatively more complexity, more bacterial taxa, and more associations
among prokaryotic taxa, relative to the abyssal network. This study reveals potentially metal variables
and community assembly mechanisms of the prokaryotic community in abyssal and hadal sediments and provides
a better understanding on the prokaryotic diversity and ecology in trench sediment ecosystems.
... In addition, HHP experiments are crucial in understanding biological processes that take place at extreme pressure conditions [29]. The deep oceans on Earth, including subsurface environments below the ocean floor, host a wide variety of organisms that must cope with high hydrostatic pressures up to the 1 kbar level and, in addition, low/high temperatures [30]. Thus, exploring the pressure-axis allows us to assess the limits of life-relevant reactions. ...
... Thus, exploring the pressure-axis allows us to assess the limits of life-relevant reactions. The cellular milieu of organisms coping with high hydrostatic pressures often shows high concentrations of osmolytes, such as methylamines, carbohydrates and amino acids, to stabilize biomolecular structure and secure their function [30][31][32]. For example, trimethylamine-N-oxide is present in diverse aquatic organisms, and its intracellular concentration increases with the depth where these organisms are thriving, thereby counteracts the deleterious effects of HHP, such as pressure-induced unfolding of proteins or dissociation of multimeric proteins [26][27][28][32][33][34]. ...
... TMAO levels increase with depth in muscles of some teleosts, skates, and crustaceans, up to about 0.3 M at 3 km depth. Other deep-sea animals have high levels of betaines such as snails, molluscs, mussels, jellyfish or sea anemones [23,[30][31][32][33][34]. Lysozyme is a small globular enzyme that is part of the innate immune system of animals [2], it shows antibacterial activity since it is capable to hydrolyze the (1-4)β-glycosidic bond between N-acetylmuramic acid and N-acetyl-Dglucosamine, the two major constituents of the peptidoglycan, the cell wall of gram-positive bacteria [2]. ...
... Seep ecosystems are typically characterized by the upward flow from deep sediments of cold fluids rich in methane and hydrogen sulfide. These fluids support diverse chemosynthetic microbial communities (Chen et al., 2022b;Feng et al., 2022a). A diverse array of seep habitats are created by different geochemical processes occurring at different locations within the cold seep area. ...
Cold seeps create diverse habitats in the deep sea and play an important role in the global carbon cycling. Anaerobic oxidation of methane (AOM) and biogenic mineralization are essential carbon pathways of methane and carbon transformation in cold seeps, however, the effects of habitat heterogeneity on the processes are still poorly understood. In this study, we investigated the microbial communities and mineral assemblages at distinct habitats in the Haima cold seep and their relationships with environmental factors. These habitats were classified as methane seep site (MS), seep-free faunal habitat (FH), and control site (CS). Bacterial communities were significantly different among the three habitats. ANME-3 archaea, Sulfurovum bacteria, and mineralization-associated microbes (e.g., Campylobacterales) were detected in high relative abundances at ROV2. Mineralogical analysis revealed abundant calcite minerals at the seep site, indicating that authigenic carbonate minerals were formed at highly active seep. Multivariate statistical analysis demonstrated that the concentrations of SO4 2–, Ca²⁺, and Mg²⁺ were significantly correlated with the presence of calcite minerals and bacterial communities. These results suggested that AOM-accompanied authigenic carbonate formation is an important factor influencing the mineral assemblages in seep habitats. This finding improves our understanding of marine microbial carbon cycling.
