Marine Organisms Research Articles

Answering the key stakeholder questions about the impact of offshore wind farms on marine life using hypothesis testing to inform targeted monitoring

Abstract Stakeholders need scientific advice on the environmental impacts of offshore wind (OW) before the facilities are installed. The utility of conventional environmental monitoring methods as a basis for forecasting OW impacts is limited because they do not explain the causes of the observed effects. We propose a multistep approach, based on process-oriented hypothesis testing, targeted monitoring and numerical modeling, to answer key stakeholder questions about planning an OW facility: Q1—Where do we place future OW farms so that impacts on the ecosystem are minimized? Q2—Which species and ecosystem processes will be impacted and to what degree? Q3—Can we mitigate impacts and, if so, how? and Q4—What are the risks of placing an OW facility in one location vs. another? Hypothesis testing can be used to assess impacts of OW facilities on target species-ecological process. This knowledge is transferable and is broadly applicable, a priori, to assess suitable locations for OW (Q1). Hypothesis testing can be combined with monitoring methods to guide targeted monitoring. The knowledge generated can identify the species/habitats at risk (Q2), help selecting/developing mitigation measures (Q3), and be used as input parameters for models to forecast OW impacts at a large spatial scale (Q1; Q4).

Increasing marine trophic web knowledge through DNA analyses of fish stomach content: a step towards an ecosystem-based approach to fisheries research.

Multispecies and ecosystem models, which are key for the implementation of ecosystem-based approaches to fisheries management, require extensive data on the trophic interactions between marine organisms, including changes over time. DNA metabarcoding, by allowing the simultaneous taxonomic identification of the community present in hundreds of samples, could be used for speeding up large-scale stomach content data collection. Yet, for DNA metabarcoding to be routinely implemented, technical challenges should be addressed, such as the potentially complicated sampling logistics, the detection of a high proportion of predator DNA, and the inability to provide reliable abundance estimations. Here, we present a DNA metabarcoding assay developed to examine the diet of five commercially important fish, which can be feasibly incorporated into routinary samplings. The method is devised to speed up the analysis process by avoiding the stomach dissection and content extraction steps, while preventing the amplification of predator DNA by using blocking primers. Tested in mock samples and in real stomach samples, the method has proven effective and shows great effectiveness discerning diet variations due to predator ecology or prey availability. Additionally, by applying our protocol to mackerel stomachs previously analyzed by visual inspection, we showcase how DNA metabarcoding could complement visually based data by detecting overlooked prey by the visual approach. We finally discuss how DNA metabarcoding-based data can contribute to trophic data collection. Our work reinforces the potential of DNA metabarcoding for the study and monitoring of fish trophic interactions and provides a basis for its incorporation into routine monitoring programs, which will be critical for the implementation of ecosystem-based approaches to fisheries management.

Unveiling nature’s beat: analyzing the acoustics of an aquatic bug in relation to urban sounds

AbstractAnthropophony is a prominent component of soundscapes worldwide and is known to impact biota. While responses to anthropophony in terrestrial and marine animals have been relatively well-studied, there is still a lack of knowledge regarding freshwater animals. In fact, freshwater taxa are among the possibly most threatened groups, and unveiling the reasons for their threat is crucial. We investigated the effect of low-frequency sounds -usually associated with anthropophony- on the stridulation of Krizousacorixa femorata, a common water bug in Mexico City. Using aerial recordings, we estimated the Normalized Difference Soundscape Index (NDSI), which is the most commonly used index to measure anthropophony, to characterize soundscapes in six city sites throughout the year. Additionally, from underwater recordings in the same sites, we obtained the peak frequency (Pf) of the stridulations, as it is the frequency with the highest energy and, therefore, the one that can travel the farthest and can be identified even in the presence of overlapping sounds. Finally, we evaluated the relationships between soundscapes and Pf through a mixed linear model. There was a negative correlation between NDSI and Pf, indicating higher-pitched stridulations at sites with dominant anthropophony. While we cannot rule out other factors contributing to stridulation variation, we remain uncertain about how low-frequency sounds impact freshwater ecosystems and the intricate relationship between soundscapes and aquatic life in urban settings.

Effects of Exposure to Electromagnetic Fields (EMFs) on Biological Systems

Electromagnetic Field (EMF) is a natural phenomenon; however, anthropogenic activities have significantly shifted its equilibrium, leading to potential deleterious effects on biological systems. As technology becomes more integrated into daily life, the increased use of electronic devices has contributed to a rise in man-made EMF exposure. This exposure can affect biological systems on physiological and molecular levels, raising concerns about its potential effects on animal development, reproductive systems, and overall ecosystem health. The review explores the physiological effects of exposure to static, extremely low-frequency (ELF), and radiofrequency (RF) fields, analyzing how EMF impacts oxidative stress, reproductive physiology, cardiovascular function, brain and nervous system activity, and DNA/RNA integrity. It also acknowledges the emerging concern of EMF in aquatic environments, where underwater power supplies and extensive underwater cable networks are sources of EMF exposure that may affect marine and freshwater species. The potential effects on marine life include disruptions to migratory patterns, altered reproductive cycles, and changes in aquatic biodiversity. The review acknowledges that research on EMF has improved over time, but significant gaps and information remain. It emphasizes the need for immediate attention to address the challenges and opportunities in this field.

Design and Fabrication of Ocean Plastic Waste Cleaner

An ocean cleaning device abstract could focus on various aspects, depending on the specific device or technology being described. With the escalating threat of ocean pollution, innovative solutions are imperative to mitigate its detrimental impacts on marine ecosystems and human livelihoods. This abstract presents a comprehensive overview of an advanced ocean cleaning device designed to tackle the burgeoning issue of marine debris. The device integrates cutting-edge technology, including [insert specific technologies], to efficiently remove various forms of pollution from coastal areas and open water on the severity of ocean pollution and the urgent need for effective cleanup technologies. It highlights the detrimental effects of marine debris on marine life, biodiversity, and coastal communities, emphasizing the importance of sustainable solutions. Here's a general abstract outline for an ocean cleaning device.This paper discusses the design principles, technological components, and operational strategies of the ocean plastic waste cleaning device. Additionally, it evaluates the device's performance through simulation models and field tests, demonstrating its effectiveness in reducing plastic pollution and contributing to sustainable ocean conservation efforts.Integrated sensors monitor water quality, temperature, and marine life, providing valuable data for environmental research and conservation efforts.Operators can remotely control the device and receive real-time data, enhancing operational efficiency and response times

Context-dependent antioxidant defense system (ADS)-based stress memory in response to recurrent environmental challenges in congeneric invasive species

AbstractMarine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities, imposing pressures on marine species. To withstand recurring environmental challenges, marine organisms, especially benthic species lacking behavioral choices to select optimal habitats, have to utilize well-established strategies such as the antioxidant defense system (ADS) to ensure their survival. Therefore, understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges. Here we conducted a comparative analysis of the physiological and transcriptional responses based on the ADS during two rounds of 'hypersalinity-recovery' challenges in two model congeneric invasive ascidians, Ciona robusta and C. savignyi. Our results demonstrated that C. savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level, while C. robusta demonstrated heightened responses at the transcriptional level. We observed distinct transcriptional responses, particularly in the utilization of two superoxide dismutase (SOD) isoforms. Both Ciona species developed physiological stress memory with elevated total SOD (T-SOD) and glutathione (GSH) responses, while only C. robusta demonstrated transcriptional stress memory. The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species. These findings support the 'context-dependent stress memory hypothesis', emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges. Our results enhance our understanding of the mechanisms of environmental challenge management in marine species, particularly those related to the ADS.

Exploring di (2-ethylhexyl) phthalate degradation by a synthetic marine bacterial consortium: Genomic insights, pathway and interaction prediction, and application in sediment microcosms

Di (2-ethylhexyl) phthalate (DEHP), a toxic phthalate ester (PAE) plasticizer, is often detected in marine sediment and biota. Our understanding of DEHP-degrading marine bacteria and the associated genetic mechanisms is limited. This study established a synthetic bacterial consortium (A02) consisting of three marine bacteria (OR05, OR16, and OR21). Consortium A02 outperformed the individual strains in DEHP degradation. Investigations into the degradation of DEHP intermediates revealed that OR05 and OR16 likely contributed to enhanced DEHP degradation by Consortium A02 via the utilization of DEHP intermediates, such as protocatechuic acid and mono (ethylhexyl) phthalate, with OR21 as the key DEHP degrader. A pathway of DEHP degradation by Consortium A02 was predicted based on genome analysis and experimental degradation. Bioaugmentation with Consortium A02 led to 80% DEHP degradation in 26 days in saline sediment (100 mg/kg), surpassing the 53% degradation by indigenous microbes, indicating the potential of A02 for treating DEHP-contaminated sediments. Meanwhile, bioaugmentation notably changed the bacterial community, with the exclusive presence of certain bacterial genera in the A02 bioaugmented microcosms, and was predicted to result in a more dynamic and active sediment bacterial community. This study contributes to the limited literature on DEHP degradation by marine bacteria and their associated genes.

Exploring the antibacterial potential of tunicate-associated bacteria (Ascidiacea) at the shipwreck site of Menjangan Kecil Waters, Karimunjawa

Menjangan Kecil Island is situated south of Karimunjawa Island and boasts a rich diversity of coral reefs and associated marine life, including tunicates. Tunicates, also known as sea squirts, produce secondary metabolites to defend against predators. This study aims to explore the antibacterial potential of tunicate-associated bacteria from shipwrecks in Menjangan Kecil Waters. The research adopts an exploratory descriptive approach. Seventy-two bacterial isolates were recovered from five tunicate specimens. Fifteen isolates exhibited antibacterial activity against Vibrio harveyi, with two isolates, KJ1.3.02.05 and KJ1.4.02.02, displaying the highest activity. Molecular identification via 16S rRNA gene amplification revealed that KJ1.3.02.05 was Sinomicrobium oceani (99.64% similarity), and KJ1.4.02.02 was Bacillus haynesii (98.64% similarity).

From Isolated Valves to a Potential Marine Living Resource: History, Documented Distribution and Sustainable Population Enhancement Possibilities of the Smooth Scallop (Flexopecten glaber) on the Romanian Coast

Until recently, the smooth scallop Flexopecten glaber (Linnaeus, 1758) was considered absent from Romanian Black Sea waters, as only isolated valves were documented on beaches of the southern coast. Yet, in 2020, the first living specimens were collected by dredging at 25 m depth in Mangalia. Moreover, in the past three years, a considerable number of live individuals were also retrieved from beam-trawling operations targeting the gastropod Rapana venosa (Valenciennes, 1846) along the Romanian coast, indicating that there is a stable population here. This remarkable expansion of F. glaber in Romanian waters may be explained as a consequence of the Black Sea’s recovery from eutrophication, reduced predatory pressure from the declining population of R. venosa and changing climate conditions. Our research aimed at using all this novel information to document for the first time the occurrence and distribution of this bivalve on the Romanian coast, also considering perspectives for the development of a new type of shellfish mariculture, avoiding any pressure on the natural stock. In total, 386 F. glaber individuals were sampled during 2020–2023, at depths between 22.5 and 33.3 m. The abundance and biomass per station oscillated between 5 and 319 specimens and 51.5 and 7377 g, respectively. A subsample of 122 specimens was preserved and analyzed in the laboratory, revealing an average shell length of 53.54 mm (±4.13 SD) and an average shell height of 49.54 mm (±3.64 SD). The smooth scallop has both ecological and economic value, which makes it a viable candidate for sustainable aquaculture by collecting spat from the most abundant areas and subsequently placing “seedlings” in the appropriate polygons for stock recovery. Ultimately, commercial exploitation from aquaculture installations can be considered, provided a permanent healthy F. glaber population is established on the Romanian coast.

Saponin monomers: Potential candidates for the treatment of type 2 diabetes mellitus and its complications.

Type 2 diabetes mellitus (T2DM), a metabolic disease with persistent hyperglycemia primarily caused by insulin resistance (IR), has become one of the most serious health challenges of the 21st century, with considerable economic and societal implications worldwide. Considering the inevitable side effects of conventional antidiabetic drugs, natural ingredients exhibit promising therapeutic efficacy and can serve as safer and more cost-effective alternatives for the management of T2DM. Saponins are a structurally diverse class of amphiphilic compounds widely distributed in many popular herbal medicinal plants, some animals, and marine organisms. There are many saponin monomers, such as ginsenoside compound K, ginsenoside Rb1, ginsenoside Rg1, astragaloside IV, glycyrrhizin, and diosgenin, showing great efficacy in the treatment of T2DM and its complications in vivo and in vitro. However, although the mechanisms of action of saponin monomers at the animal and cell levels have been gradually elucidated, there is a lack of clinical data, which hinders the development of saponin-based antidiabetic drugs. Herein, the main factors/pathways associated with T2DM and the comprehensive underlying mechanisms and potential applications of these saponin monomers in the management of T2DM and its complications are reviewed and discussed, aiming to provide fundamental data for future high-quality clinical studies and trials.

Species-specific and habitat-dependent bioaccumulation of halogenated flame retardants in marine organisms from estuary to coastal seas

Halogenated flame retardants (HFRs) have attracted global attention owing to their adverse effects on ecosystems and humans. The Shandong Peninsula is the largest manufacturing base for HFRs in East Asia, yet its impacts on marine ecosystems are unclear. Seventeen HFRs were analyzed in organisms captured from the Xiaoqing River estuary, Bohai Sea (BS), Yellow Sea and Northern East China Sea to investigate the distribution and bioaccumulation of HFRs on a broad scale. The results showed a downward trend in ΣHFR concentrations from the estuary (37.7 ng/g lw on average) to Laizhou Bay (192 ng/g lw) and to coastal seas (3.13 ng/g lw). The concentrations of ΣHFRs were significantly higher in demersal fish (0.71–198 ng/g lw) and benthic invertebrates (0.81–3340 ng/g lw) than in pelagic fish (0.30–27.6 ng/g lw), reflecting a habitat dependence. The concentrations of higher-brominated homologs were greater in benthic invertebrates, whereas a greater level of lower-brominated PBDE congeners was observed in fish, suggesting different profiles between species. Furthermore, the analogue composition of HFRs in fish was similar to that in the dissolved phase of seawater, whereas the HFR pattern in benthic invertebrates was consistent with the profile in sediment. The concentrations of HFRs in organisms vary widely depending on emissions from anthropogenic activities, whereas bioaccumulation patterns are strongly influenced by species and habitat.

Naturally Occurring Norsteroids and Their Design and Pharmaceutical Application

Naturally Occurring Norsteroids and Their Design and Pharmaceutical Application

Exploring Human Health Benefits from Marine Biomedical Research with Fishes

Marine organisms, particularly fishes, harbor a treasure trove of bioactive compounds with immense potential for human health applications. In this review, we delve into the diverse array of bioactive molecules derived from marine fishes and their implications for biomedical research. We explore the therapeutic properties of fish-derived compounds, including antimicrobial peptides, omega-3 fatty acids, collagen, and bioactive peptides, among others andthe mechanisms of action and preclinical studies supporting the use of these compounds in various human health conditions, such as cardiovascular disease, cancer, inflammatory disorders, and neurodegenerative diseases. Additionally, we highlight the importance of sustainable sourcing and ethical considerations in marine biomedical research. Overall, this review underscores the significance of marine fishes as a source of novel therapeutic agents and the promising avenues they offer for advancing human health.

Exposure to nanoplastics and nanomaterials either single and combined affects the gill-associated microbiome of the Antarctic soft-shelled clam Laternula elliptica

Nanoplastics and engineering nanomaterials (ENMs) are contaminants of emerging concern (CECs), increasingly being detected in the marine environment and recognized as a potential threat for marine biota at the global level including in polar areas. Few studies have assessed the impact of these anthropogenic nanoparticles in the microbiome of marine invertebrates, however combined exposure resembling natural scenarios has been overlooked. The present study aimed to evaluate the single and combined effects of polystyrene nanoparticles (PS NP) as proxy for nanoplastics and nanoscale titanium dioxide (nano-TiO2) on the prokaryotic communities associated with the gill tissue of the Antarctic soft-shell clam Laternula elliptica, a keystone species of marine benthos Wild-caught specimens were exposed to two environmentally relevant concentrations of carboxylated PS NP (PS–COOH NP, ∼62 nm size) and nano-TiO2 (Aeroxide P25, ∼25 nm) as 5 and 50 μg/L either single and combined for 96h in a semi-static condition.Our findings show a shift in microbiome composition in gills of soft-shell clams exposed to PS NP and nano-TiO2 either alone and in combination with a decrease in the relative abundance of OTU1 (Spirochaetaceae). In addition, an increase of gammaproteobacterial OTUs affiliated to MBAE14 and Methylophagaceae (involved in ammonia denitrification and associated with low-quality water), and the OTU Colwellia rossensis (previously recorded in polluted waters) was observed. Our results suggest that nanoplastics and nano-TiO2 alone and in combination induce alterations in microbiome composition by promoting the increase of negative taxa over beneficial ones in the gills of the Antarctic soft-shell clam. An increase of two low abundance OTUs in PS-COOH NPs exposed clams was also observed. A predicted gene function analysis revealed that sugar, lipid, protein and DNA metabolism were the main functions affected by either PS-COOH NP and nano-TiO2 exposure. The molecular functions involved in the altered affiliated OTUs are novel for nano-CEC exposures.

Real Time Recognition of Underwater Images using Deep Learning

This study focuses on the development of an effective image recognition system tailored for underwater environments. The objective is to create a robust and efficient artificial neural network capable of accurately categorizing underwater images amidst challenges like noise, distortion, and variable lighting conditions. The system's primary function is to classify images into predefined categories, such as distinct species of marine organisms, underwater objects, or environmental conditions.

Evaluation of surfactant-aided polycyclic aromatic hydrocarbon biodegradation by molecular docking and molecular dynamic simulation in the marine environment

Marine oil spills directly cause polycyclic aromatic hydrocarbons (PAHs) pollution and affect marine organisms due to their toxic property. Chemical and bio-based dispersants composed of surfactants and solvents are considered effective oil spill-treating agents. Dispersants enhance oil biodegradation in the marine environment by rapidly increasing their solubility in the water column. However, the effect of dispersants, especially surfactants, on PAHs degradation by enzymes produced by microorganisms has not been studied at the molecular level. The role of the cytochrome P450 (CYP) enzyme in converting contaminants into reactive metabolites during the biodegradation process has been evidenced, but the activity in the presence of surfactants is still ambiguous. Thus, this study focused on the evaluation of the impact of chemical and bio-surfactants (i.e., Tween 80 (TWE) and Surfactin (SUC)) on the biodegradation of naphthalene (NAP), chrysene (CHR), and pyrene (PYR), the representative components of PAHs, with CYP enzyme from microalgae Parachlorella kessleri using molecular docking and molecular dynamics (MD) simulation. The molecular docking analysis revealed that PAHs bound to residues at the CYP active site through hydrophobic interactions for biodegradation. The MD simulation showed that the surfactant addition changed the enzyme conformation in the CYP-PAH complexes to provide more interactions between the enzyme and PAHs. This led to an increase in the enzyme's capability to degrade PAHs. Binding free energy (ΔG‌‌Bind) calculations confirmed that surfactant treatment could enhance PAHs degradation by the enzyme. The SUC gave a better result on NAP and PYR biodegradation based on ΔG‌‌Bind, while TWE facilitated the biodegradation of CHR. The research outputs could greatly facilitate evaluating the behaviors of oil spill-treating agents and oil spill response operations in the marine environment.

Fisheries Impact Pathway: Making Global and Regionalised Impacts on Marine Ecosystem Quality Accessible in Life Cycle Impact Assessment

Overexploitation in wild-capture fisheries is a principal driver of marine biodiversity loss. Currently, efforts are underway to improve the representation of marine damage indicators in Life Cycle Impact Assessment (LCIA) methods. The recently operationalised fisheries impact pathway has introduced fishing impacts on the marine system into the LCIA framework, and the current work seeks to further develop this complex pathway. In total, 5000+ Characterisation Factors for exploited marine organisms have been re-computed with updated fisheries production data (2018), exploring temporal effects on dynamic, biotic resource impacts. An estimation of discarded unwanted by-catch is incorporated into the characterisation. Regional to global scaling factors are tested for the representation of species-specific vulnerability. The temporal and spatial variations in impacts reflect the dynamic nature of real-world fisheries trends, global average impacts increased by 41% (2015–2018). Discarding as an additive, regional estimate increases impacts, most notably for lower impacted stocks. The retention of species-specific detail relating to species distributions is of particular relevance to fisheries when computing global-scale impacts. Updating CFs improves the relevance of the fisheries impact assessment, and continued periodic re-computation is recommended to maintain relevance with real-world trends. Data availability remains a challenge to large-scale marine impact assessment and the continued development of this emergent impact pathway is expected.

Quaternary fossil diversity of stingrays (Chondrichthyes: Myliobatiformes) from the eastern coast of South America, Brazil, southwestern Atlantic

Sharks, rays, and chimeras have a limited fossil record compared to other taxa due to their predominantly cartilaginous skeletal structure. Fossilization tends to preserve anatomic structures such as teeth, scales, cephalic and caudal fins, and other fins. The Myliobatiformes order, derived from rays, is characterized by viviparity and distinctive serrated stings, with some species exhibiting hexagonal dental plates. These marine organisms inhabit coastal zones globally. This study aims to enhance understanding of Quaternary biodiversity and paleoecology in southern Brazil, focusing on fossils from the Myliobatiformes order, specifically dental plates and stings. Material from biodetrital deposits at Concheiros and Hermenegildo beaches in Santa Vitória do Palmar, Rio Grande do Sul, Brazil, were analyzed. Six taxa were identified from fossil teeth, including Myliobatis ridens, Myliobatis freminvillei, Myliobatis goodei, and Myliobatis sp. (Morphotypes 1 and 2), marking their first Pleistocene fossil record in Brazil. Most teeth couldn't be classified at the species level, but genera were discerned. Fossil stings were described, possibly associated with Myliobatiformes. Results revealed notable differences between identified fossil taxa and their modern counterparts in the western Atlantic Ocean, currently considered common. M. ridens was the most frequent species in the fossil samples, followed by M. freminvillei, with fewer records for M. goodei. Conversely, the current scenario shows M. goodei as the most abundant, followed by M. freminvillei, while M. ridens is Critically Endangered. This investigation expands knowledge of fossil species on the southern Brazilian coast, confirming the presence of M. ridens, M. freminvillei, and M. goodei during the Quaternary.

Polyhydroxy steroids isolated from starfish (Asterina pectinifera) and their embryotoxicity

Many marine organisms possess an essential capacity to produce secondary metabolites that exhibit toxic characteristics. A new polyhydroxy steroid, 24-methyl-5α-cholestane-24(28)-ene-3β, 4β, 6α, 7α, 8, 15β, 16β, 26-octol-6-O-sodium sulphate (1) was isolated from starfish (Asterina pectinifera), along with five polar steroid compounds (2–6) that were previously identified. NMR (1H and 13C NMR, 1H-1H COSY, HSQC, HMBC, and NOESY) and HR-ESI-MS were employed for structure elucidations. The embryotoxicity and teratogenicity of the isolated compounds were assessed using embryos of marine medaka (Oryzias melastigma). Compound 5 exhibited moderate embryotoxicity (96h-LC50: 65 μM).

The creation of the Muraka, a Maldivian underwater hotel: A story of sea life, more-than-human architecture, and alloútopic tourism

Answering Huijbens and Jóhannesson’s call to investigate tourist destination development through a relational ontology marked by a vital materialism, this paper focuses on the creation of the Muraka. The Muraka is the underwater villa of the Conrad Maldives Rangali Island—an ultra-luxury resort located in Alifu Dhaalu Atoll. No social scientific research has ever been conducted at underwater hotels. Drawing upon fieldwork at the Muraka—part of a broader project on three underwater hotels (conducted in Singapore, Tanzania, and the Maldives), we aim to contribute original knowledge to more-than-human geographies and tourist studies by bringing attention to the architectural relations that entangle underwater hotels with their environments. In doing so we become attuned to more-than-human lives and create narratives that can help us imagine new relations with the planet both within and beyond the realm of tourist encounters. By focusing in particular on the creation of the Muraka through the lens of the original concept of alloutopia, we contribute to non-representational and more-than-human perspectives on tourism