Diverse Marine Organisms Research Articles

Local freshwater fluxes determine salinity variations of the Bohai Sea: Based on 60 years of observations

Salinity, a fundamental characteristic of seawater, significantly influences the ocean's physicochemical properties and directly affects marine biodiversity and its spatial distribution. The semi-enclosed Bohai Sea is home to diverse marine organisms and serves as a critical area for human mariculture. Salinity variations in this region are crucial for the stability of the ecosystem and the sustainability of the marine economy. However, significant discrepancies have been observed between the practical salinity measurements of the Bohai Sea in winter 2007 and that recorded in widely used national and international marine atlases prior to 2000. To identify these discrepancies, this study systematically investigates the salinity variations and the regulatory mechanisms in the Bohai Sea. First, we constructed a climatological salinity dataset with a broader temporal scope based on in-situ salinity data from 1960 to 2020, confirming that the climatological salinity field of the Bohai Sea did not undergo a significant shift, but exhibited phase changes. Subsequently, using the principles of conservation of mass and salinity, we developed a box model to analyze annual salinity changes in the Bohai Sea. This model was optimized using in-situ hydrological measurements and reanalysis data spanning over 60 years, successfully revealing the central regulatory role of local freshwater fluxes in annual salinity changes in the Bohai Sea. Furthermore, we elucidated that the anomalously high salinity in the Bohai Sea in the winter of 2007 resulted from the cumulative effect of several consecutive years of negative freshwater fluxes. The results of this study not only enhance our understanding and prediction of salinity changes in semi-enclosed seas, providing a scientific basis for ecosystem protection and management, but also offer valuable insights for studying long-term salinity changes in other semi-enclosed seas.

An Overview on the Synthesis of Lamellarins and Related Compounds with Biological Interest.

Lamellarins are natural products with a [3,4]-fused pyrrolocoumarin skeleton possessing interesting biological properties. More than 70 members have been isolated from diverse marine organisms, such as sponges, ascidians, mollusks, and tunicates. There is a continuous interest in the synthesis of these compounds. In this review, the synthetic strategies for the synthesis of the title compounds are presented along with their biological properties. Three routes are followed for the synthesis of lamellarins. Initially, pyrrole derivatives are the starting or intermediate compounds, and then they are fused to isoquinoline or a coumarin moiety. Second, isoquinoline is the starting compound fused to an indole moiety. In the last route, coumarins are the starting compounds, which are fused to a pyrrole moiety and an isoquinoline scaffold. The synthesis of isolamellarins, azacoumestans, isoazacoumestans, and analogues is also described. The above synthesis is achieved via metal-catalyzed cross-coupling, [3 + 2] cycloaddition, substitution, and lactonization reactions. The title compounds exhibit cytotoxic, multidrug resistance (MDR), topoisomerase I-targeted antitumor, anti-HIV, antiproliferative, anti-neurodegenerative disease, and anti-inflammatory activities.

Biotopes of the intertidal zone in Clarence Island (south of the Strait of Magellan).

The characteristics of the Strait of Magellan promote the formation of unique environments, with diverse habitats and marine organisms. This fragmentation of the landscape generates diverse little-explored ecological associations, especially in the zone of sub-Antarctic islands of the Tierra del Fuego archipelago. One way to address this lack of knowledge is through the biotope characterization methodology, with ecological units composed of the habitat and the communities associated with these environments, obtaining data and information on the dominant and incidental taxonomic groups. This is a good research model to conduct baseline studies in coastal benthic marine environments. A data set in Darwin Core standard is presented of the species that make up the intertidal biotopes of Clarence Island (Tierra del Fuego Archipelago, south of the Strait of Magellan). This includes 50 identified species and the specific coordinates for each sampled location, with a total of 1400 georeferenced records. Mollusks were the most diverse taxon with 21 species, followed by algae (14 species). Sessile organisms such as the barnacles Elminiuskingii and Austromegabalanuspsittacus predominate in these ecosystems, followed by bivalve mollusks such as Choromytiluschorus and Mytiluschilensis, which together with Nacellamagellanica and the alga Hildenbrandia sp. make up more than 50% of the total records. The inclusion of biotope patterns in this study complements the information on benthic marine flora and fauna in the intertidal zone, including new records for the coast in the Clarence Island area, which is within the boundary of the Kawésqar National Park.

Thallium toxicity to temperate and tropical marine organisms: Derivation of water quality guidelines to protect marine life

A lack of thallium (Tl) toxicity data for marine organisms has hampered the development of water quality guidelines for protecting marine life and assessing ecological hazard/risk. This study assessed the toxicity (EC10/EC50) of Tl in natural seawater (salinity 34 psu and pH 8.05) to 26 functionally diverse marine organisms (19 phyla from five trophic levels) from a variety of temperate and tropical coastal marine habitats. EC10 values ranged from 3.0 μg/L (copepod, Acartia tranteri) to 489 μg/L (cyanobacterium, Cyanobium sp.), while EC50 values ranged from 9.7 μg/L to 1550 μg/L. Thallium(I) was the dominant (86–99 %) oxidation state in test waters across the range of EC10 and EC50 values. Thallium toxicity (EC10/EC50) did not differ between temperate and tropical marine organisms. New, reliable, long-term Tl water quality guidelines were derived using species sensitivity distributions (with model-averaging) to protect marine life in Australia (e.g., 3.9 μg/L for 95 % species protection).

Coastal Archaeology and Historical Ecology for a Changing Planet

Our ocean planet is home to diverse marine environments and organisms that played an important role in human evolution and ecology. Today, coastal marine ecosystems are dramatically degraded and threatened by climate change, habitat destruction, overfishing, and more, leaving key questions about the future of ocean ecosystems in increasingly unstable times. Archaeology provides perspectives on past marine ecosystems and people’s role in shaping and influencing coastal environments prior to the dramatic changes of the postindustrial era. Drawing on archaeological research from the California Coast and the Chesapeake Bay, I explore how an understanding of long-term human interactions with marine ecosystems can help address contemporary environmental challenges and better prepare us for an uncertain future. Although clear examples of archaeological research guiding present-day biological conservation management and policy are limited, there are important signs of success. These include collaboration with Indigenous communities; growing recognition by biologists, ecologists, and other scientists of the significance of archaeological and historical ecological perspectives; and continued emphasis on the links between environmental conservation and social justice.

Nitroxide-Containing Amphiphilic Random Terpolymers for Marine Antifouling and Fouling-Release Coatings

Two types of amphiphilic random terpolymers, poly(ethylene glycol methyl ether methacrylate)-ran-poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate)-ran-poly(polydimethyl siloxane methacrylate) (PEGMEMA-r-PTMA-r-PDMSMA), were synthesized and evaluated for antifouling (AF) and fouling-release (FR) properties using diverse marine fouling organisms. In the first stage of production, the two respective precursor amine terpolymers containing (2,2,6,6-tetramethyl-4-piperidyl methacrylate) units (PEGMEMA-r-PTMPM-r-PDMSMA) were synthesized by atom transfer radical polymerization using various comonomer ratios and two initiators: alkyl halide and fluoroalkyl halide. In the second stage, these were selectively oxidized to introduce nitroxide radical functionalities. Finally, the terpolymers were incorporated into a PDMS host matrix to create coatings. AF and FR properties were examined using the alga Ulva linza, the barnacle Balanus improvisus, and the tubeworm Ficopomatus enigmaticus. The effects of comonomer ratios on surface properties and fouling assay results for each set of coatings are discussed in detail. There were marked differences in the effectiveness of these systems against the different fouling organisms. The terpolymers had distinct advantages over monopolymeric systems across the different organisms, and the nonfluorinated PEG and nitroxide combination was identified as the most effective formulation against B. improvisus and F. enigmaticus.

Effects of Hypoxia on Coral Photobiology and Oxidative Stress.

Simple SummaryWith the growing importance of climate change research, the biological effects of oxygen loss on marine biota remain understudied. Coral reefs support diverse marine organisms and provide valuable ecosystem services. Deoxygenation may induce mass coral mortality and reduce species richness on coral reefs. Corals exposed to nocturnal hypoxia may experience detrimental effects due to induced oxidative stress caused by the increase in reactive oxygen species (ROS). The stress interferes with the most fundamental biological processes vital for the symbiosis between corals and photosynthetic algae. In this study, the coral Acropora spp. exhibited evident injury in photosynthetic apparatus, de-epoxidation state and DNA. However, besides that, there were no signs of engaged antioxidant defense mechanisms against ROS or pigment degradation, which leads to a conclusion that these corals may be resilient to such oxygen daily oscillations. Nevertheless, while corals might survive such short-term abiotic stress, the growing number and intensity of hypoxic events across the global ocean may pose a massive threat to these keystone invertebrate species.Global ocean oxygen (O2) content is decreasing as climate change drives declines in oxygen solubility, strengthened stratification of seawater masses, increased biological oxygen consumption and coastal eutrophication. Studies on the biological effects of nocturnal decreased oxygen concentrations (hypoxia) on coral reefs are very scarce. Coral reefs are fundamental for supporting one quarter of all marine species and essential for around 275 million people worldwide. This study investigates acute physiological and photobiological responses of a scleractinian coral (Acropora spp.) to overnight hypoxic conditions (<2 mg/L of O2). Bleaching was not detected, and visual and physical aspects of corals remained unchanged under hypoxic conditions. Most photobiological-related parameters also did not show significant changes between treatments. In addition to this, no significant differences between treatments were observed in the pigment composition. However, hypoxic conditions induced a significant decrease in coral de-epoxidation state of the xanthophyll cycle pigments and increase in DNA damage. Although the present findings suggest that Acropora spp. is resilient to some extent to short-term daily oxygen oscillations, long-term exposure to hypoxia, as predicted to occur with climate change, may still have deleterious effects on corals.

Isolation, Bioactivities, and Synthesis of Lamellarin Alkaloids: A Review

Abstract: Lamellarin alkaloid is a large class of marine alkaloids with diverse bioactivities. These heterocycles have been isolated from diverse marine organisms, mainly ascidians and sponges. They possess a fused 14-phenyl-6H-[1]benzopyrano[40,30:4,5] pyrrolo[2,1- a]isoquinoline or non-fused 3,4-diarylpyrrole-2-carboxylate ring systems. Until now, more than 50 lamellarins have been isolated from marine organisms. Various lamellarins exhibit valuable bioactivities, such as cytotoxicity, topoisomerase I inhibition, protein kinases inhibition, multidrug resistance reversal, and anti-HIV-1 activity. Due to their valuable biological activity, the synthesis of lamerallins has received great attention of chemists and a vast number of synthetic methods have been developed. This article gives overview of studies on lamellarins isolation, their bioactivities, and synthetic approaches for their total synthesis.

A review of plastic and microplastic pollution towards the Malaysian marine environment

Abstract Abstract Plastics are widely used in daily lives but uncontrollably dumped into the ocean by humans. Plastic pollution is harmful to the marine environment and organisms as it can break down into microplastics (MPs) and release chemicals into the water. Microplastics (MPs) are small, fragmented plastic pieces (&lt; 5mm) that exist in every part of the ocean. MPs are problematic because they are hard to recover and can be easily consumed by marine organisms, resulting in bioaccumulation and biomagnification in the food chain. Malaysia is a tropical country located at the heart of Southeast Asia (SEA) and owns diverse marine ecosystems and organisms. Malaysia is affected by plastic pollution due to rapid development and intense economic activities. In this paper, we discuss the plastic pollution crisis in Malaysia and its contributing factor. We review the possible effect on the marine environment in Malaysia. Knowledge gaps to manage plastic pollution in Malaysia are also addressed. As MPs are consistently discovered in different compartments of the Malaysian marine environment, there is an urgency to develop a better waste management system and strong cooperation from all societal levels to handle plastic pollution in the country.

High-Throughput Screening of a Marine Compound Library Identifies Anti-Cryptosporidium Activity of Leiodolide A.

Cryptosporidium sp. are apicomplexan parasites that cause significant morbidity and possible mortality in humans and valuable livestock. There are no drugs on the market that are effective in the population most severely affected by this parasite. This study is the first high-throughput screen for potent anti-Cryptosporidium natural products sourced from a unique marine compound library. The Harbor Branch Oceanographic Institute at Florida Atlantic University has a collection of diverse marine organisms some of which have been subjected to medium pressure liquid chromatography to create an enriched fraction library. Numerous active compounds have been discovered from this library, but it has not been tested against Cryptosporidium parvum. A high-throughput in vitro growth inhibition assay was used to test 3764 fractions in the library, leading to the identification of 23 fractions that potently inhibited the growth of Cryptosporidium parvum. Bioassay guided fractionation of active fractions from a deep-sea sponge, Leiodermatium sp., resulted in the purification of leiodolide A, the major active compound in the organism. Leiodolide A displayed specific anti-Cryptosporidium activity at a half maximal effective concentration of 103.5 nM with selectivity indexes (SI) of 45.1, 11.9, 19.6 and 14.3 for human ileocecal colorectal adenocarcinoma cells (HCT-8), human hepatocellular carcinoma cells (Hep G2), human neuroblastoma cells (SH-SY5Y) and green monkey kidney cells (Vero), respectively. The unique structure of leiodolide A provides a valuable drug scaffold on which to develop new anti-Cryptosporidium compounds and supports the importance of screening natural product libraries for new chemical scaffolds.

Transcriptional response in the whiteleg shrimp (Penaeus vannamei) to short-term microplastic exposure

The ingestion of microplastics by diverse marine organisms induces behavioral disorders, physiological changes, and immune and stress responses. The negative effects of microplastic exposure in penaeid shrimps are still unclear despite the annual increase in the consumption of these food sources by humans and in marine aquaculture. Therefore, this study aimed to investigate the potential negative effects of microplastic exposure and gain a deeper understanding of its impacts on culturing penaeid shrimp. We generated RNA sequencing data from the whiteleg shrimp (Penaeus vannamei) artificially exposed to microplastics and analyzed the differentially expressed genes. Based on transcriptional comparisons, exposure to microplastics induces cardiac muscle dysfunction and promotes stress and immune responses in whiteleg shrimp. Thus, we confirmed the negative impact of microplastic exposure in whiteleg shrimp. These results provide a foundation for studies on the biological effects of microplastic ingestion on aquaculture species and their potential impact on humans through their consumption of these important marine resources.

Biological action mechanisms of fucoxanthin extracted from algae for application in food and cosmetic industries

Fucoxanthin is a pigment present in diverse marine organisms such as micro and macro-algae. The most relevant source of fucoxanthin has been described to be the group of the brown macroalgae, also known as Phaeophyceae. The presence of the fucoxanthin, a xanthophyll, found as an accessory pigment in the chloroplasts of the brown algae is responsible for providing them their characteristic color. The market size of this carotenoid, expected to reach US$ 120 million by 2022, reflects its industrial importance, especially remarkable as a food or cosmetic ingredient. Therefore, it is critical to recognize the main sources of fucoxanthin as well as the most efficient extraction and purification methods that allow obtaining the best production ratio for such a valuable molecule. Throughout this review very different preventive properties of the fucoxanthin have been included, such as antioxidant, anticancer, antiangiogenic, anti-inflammatory, cytoprotective, antiobesity, neuroprotective and its skin protective effects. The stability, bioavailability and toxicity of the fucoxanthin have also been reviewed through diverse biological, in vitro and in vivo assays. Thus, the main aim of this work is to provide a wide and global vision of the fucoxanthin in terms of productive species, efficient recovery techniques and multiple industrial applications.

Identifying the specific-targeted marine cerebrosides against SARS-CoV-2: an integrated computational approach.

Cerebrosides are a group of metabolites belonging to the glycosphingolipids class of natural products. So far, 167 cerebrosides, compounds 1–167, have been isolated from diverse marine organisms or microorganisms. The as yet smaller number of compounds that have been studied more in depth proves a potential against challenging diseases, such as cancer, a range of viral and bacterial diseases, as well as inflammation. This review provides a comprehensive summary on this so far under-explored class of compounds, their chemical structures, bioactivities, and their marine sources, with a full coverage to the end of 2020. Today, the global pandemic concern, COVID-19, has claimed millions of death cases around the world, making the development of anti-SARS-CoV-2 drugs urgently needed for such a battle. Accordingly, selected examples from all subclasses of cerebrosides were virtually screened for potential inhibition of SARS-CoV-2 proteins that are crucially involved in the viral–host interaction, viral replication, or in disease progression. The results highlight five cerebrosides that could preferentially bind to the hACE2 protein, with binding scores between −7.1 and −7.6 kcal mol−1 and with the docking poses determined underneath the first α1-helix of the protein. Moreover, the molecular interaction determined by molecular dynamic (MD) simulation revealed that renieroside C1 (60) is more conveniently involved in key hydrophobic interactions with the best stability, least deviation, least ΔG (−6.9 kcal mol−1) and an RMSD value of 3.6 Å. Thus, the structural insights assure better binding affinity and favorable molecular interaction of renieroside C1 (60) towards the hACE2 protein, which plays a crucial role in the biology and pathogenesis of SARS-CoV-2.

Acceleration of somatic cell reprogramming into the induced pluripotent stem cell using a mycosporine-like amino acid, Porphyra 334

Porphyra 334 (P334), a mycosporine-like amino acid (MAA), is a secondary metabolite found in diverse marine and terrestrial organisms and has several beneficial effects on fibroblast proliferation, wound healing, and antioxidant activity. Here, we report that P334 accelerates the cell reprogramming process of mouse tail-tip fibroblasts (TTFs) and human dermal papilla (HDP) cells into induced pluripotent stem cells (iPSCs). We found that P334 significantly improved the cell reprogramming efficiency by activating the tri-methylation of histone 3 lysine 4 (H3K4me3), which controls mesenchymal to epithelial transition (MET) during the reprogramming process. Thus, we found that P334 directly regulates epigenetic changes, providing an efficient approach for natural compound-based cell reprogramming.

Impact of 2004 co-seismic coastal uplift on the mangrove cover along the North Andaman Islands

The December 2004 earthquake and the subsequent tsunami have incurred devastating impacts on vital habitats along the Indian coastal region, where few of them are irreversible. The earthquake has uplifted the northern Andaman coast, resulting in a drastic reduction of tidal water influx into the adjoining mangrove-laden mudflats. Satellite images of the period from 2003 to 2019 were used to assess the impact of coastal upliftment on the northern Andaman mangroves. Through satellite data analysis, we report a loss of 6500 ha of northern Andaman mangroves. Tidal hydrodynamics simulation under the post-earthquake scenario showed a vast area of mudflats deprived of tidal influx. This reduction in the tidal inundation has incurred a gradual and permanent mangrove area degradation. The earthquake impact on the mangroves was not spontaneous, but a gradual process, where the mangroves were intact until Mach 2006. The earthquake and the resultant coastal uplift have significantly altered the coastal geomorphology as well as the plant demography of the study area. Field visit revealed the terrestrial vegetation growth along the erstwhile mudflats, and vast areas of mangrove peat are observed, surrounded by successions of marshy and terrestrial plants. As mangroves are preferred habitat for diverse marine and terrestrial organisms and act as a vital food source and juvenile shelters for various fish species, the extensive loss of mangrove area may adversely affect a large scale biological ecosystem.

Therapeutic Application of Diverse Marine-derived Natural Products in Cancer Therapy.

Natural products (NPs) are useful sources of bioactive compounds and play important roles in the development and discovery of new drugs for diverse human diseases. Most natural products originate from terrestrial species, but diverse marine organisms are another source of new agents for cancer therapy. Natural products derived from marine organisms show diverse pharmacological activities via bioactive secondary metabolites. They regulate biological activities, such as cell proliferation, cell viability, induction of ROS production, ER stress, and apoptosis via modulation of cellular mechanisms in many cancers. Many natural products isolated from marine species require further study to elucidate the efficacy of their biological activity and anticancer effects. In this review, we summarize the biological properties and anticancer effects of diverse natural products extracted from marine organisms and their roles in tumor therapy.

Long-term Effects of a Cardiovascular Health Supplement on Blood Pressure in Adults with Prehypertension and Stage 1 Hypertension

Marine ecosystems are both stressed and threatened by pesticides that are used on land. Nevertheless, research on the impact of pesticides on coral reefs and the underlying mechanisms is still in its infancy. The insecticide chlordecone is a persistent organic pollutant with carcinogenic effects in rats and mice. Chlordecone has been detected in diverse marine organisms in the Caribbean, but unexpectedly, also in French Polynesia.We combined transcriptomic and morphologic analyses of analyses the response of the coral Pocillopora damicornis to chlordecone stress. We compared chlordecone stress with thermal stress to determine a chlordecone-specific response.We found eight transcripts related to the P450-1A or P450-3A families that were specifically overexpressed in response to chlordecone. There was also sequential overexpression of transcripts involved in apoptosis and degradation of cellular matrix proteins. Finally, we report the first observation of chlordecone-induced P. damicornis polyp bail-out. Altogether, these results strongly suggest that apoptosis and expression of genes belonging to the cathepsin family are sequentially regulated processes leading to coenosarc dissociation and loss.

The Bacteriocinogenic Potential of Marine Microorganisms

One of the modern antibacterial strategies to control various infectious pathogens in agriculture, veterinary medicine, and the food industry is the use of bacteriocins, which are potent antimicrobial peptides produced by almost all species of bacteria. The wide distribution of antibiotic-resistant bacteria, as well as the increasing awareness of the importance of the normal human biocenosis for health, necessitates the study of this new class of antimicrobial agents, whose application is recognized an alternative strategy for the treatment of infectious diseases. Among diverse marine organisms, bacteria are considered the most numerous. They are a promising source of bacteriocins, which play an important role in regulating competitive interactions in marine microbial systems. In the marine environment, with its high competition for space and resources, bacteria produce more potent bacteriocins than those isolated from other ecosystems. The scientific substantiation of the relevance of the research on the biological properties of these peptides is associated with the prospect of industrial cultivation of their producers in maricultures, as well as with the use of bacteriocins for medical and veterinary purposes.

Calcium phosphate and calcium carbonate mineralization of bioinspired hydrogels based on β-chitin isolated from biomineral of the common cuttlefish (Sepia officinalis, L.)

Chitin, a bioactive, antibacterial and biodegradable polymer is commonly utilized by diverse marine organisms as the main scaffold material during biomineralization. Due to its properties, chitin is also of interest as a component of organo-inorganic composites for diverse biomedical applications. In this study, chitinous fibers isolated from the cuttlebone of the common cuttlefish (Sepia officinalis, L.) are characterized and evaluated for use as an integral part of mineralized hydrogels for biomedical applications. Since marine organisms use calcium carbonates (CaCO3), while vertebrates use calcium phosphates (CaP) as the main inorganic hard tissue components, and both minerals are used in hard tissue engineering, they were compared to determine which composite is potentially a better biomaterial. Hydrogel mineralization was conducted by subsequent dipping into cationic and anionic reactant solutions, resulting in the formation of a CaCO3 or CaP coating that penetrated into the hydrogel. Obtained composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), rheology, swelling tests and simple compression. The results indicate that β-chitin can be used for the preparation of moldable hydrogels that are easily mineralized. Mineralized hydrogels have higher elasticity than non-mineralized ones while swelling is better if the extent of mineralization is lower. Further optimization of the hydrogels composition could improve their stress response and Young’s modulus, where the current hydrogel with a higher extent of CaP mineralization excels in comparison to all other investigated composites.

Silicon consumption kinetics by marine sponges: An assessment of their role at the ecosystem level

AbstractThe silicic acid (DSi) is a dissolved nutrient used by diverse marine organisms to build their skeletons of biogenic silica (BSi). This consumption, mostly due to diatoms, largely determines the availability of DSi in the photic ocean. Yet growing evidence suggests that Si consumers traditionally disregarded, such as the siliceous sponges, may also play a role. This study investigated the kinetics of DSi utilization by two demosponges as a function of both DSi availability and duration of the incubation period (24 h vs. 48 h). Consumption increased with increasing DSi availability following a saturable Michaelis–Menten kinetics. Haliclona simulans saturated at about 70 μM (Km = 45.9) and Suberites ficus around 130 μM (Km = 108.2). Forty‐eight hour incubations yielded more conservative consumption rates than 24 h incubations, particularly when DSi availability was far below saturation. DSi concentrations in the sponge natural habitats (0.2–15 μM) were consistently much lower than required for efficient elaboration of the BSi skeleton, suggesting a chronic DSi limitation. The DSi consumption kinetics was combined with quantifications of sponge biomass in the Bay of Brest (France), which was used as case study. In this system, sponges consume daily 0.10 ± 0.19 mmol Si m−2 and about 6.4 × 106 mol Si yearly. This activity represents 7.6% of the net annual BSi production in the Bay, a figure overlooked in previous nutrient balances based only on diatoms. Since the world marine Si cycle does not yet incorporate the contribution of sponges, its global BSi production budget may also be underestimated.