Distinct seasonality of chytrid-dominated benthic fungal communities in the neritic oceans (Bohai Sea and North Yellow Sea)

High performances of cellulose nanocrystal based bicomponent supramolecular hydrogel lubricant

To improve the limitations of water-based lubricants, a novel cellulose nanocrystal based supramolecular hydrogel (CNC/x-DG/y) was prepared by mixing cellulose nanocrystal (CNC) and diglycerol (DG) into deionized water (DW). The hydrogel was characterized to determine its material ratio and gelation mechanism. When DW was fixed at 1 mL, CNC content should be no <2.4 wt% and DG content 0.1-1.3 mL. The gelification was driven by the multiple H-bond network between CNC and DG, which immobilized water molecules. The rheological performances, the anti-rust property and the volatilization behaviour of the hydrogel were further studied. The results showed that the hydrogel had satisfactory viscoelasticity, excellent thermal stability, strong creep recovery, high anti-rust performance and low volatilization rate, which were exactly its advantages for use as lubricant. A typical representative of the hydrogel, namely CNC/2.4-DG/0.1, was selected to evaluate the tribological performances, and the resulting worn surfaces were analyzed. CNC/2.4-DG/0.1 exhibited a lower friction coefficient of 0.059 and a smaller wear volume of 0.81 × 10-3 mm3, compared to DW(1 mL) + CNC(2.4 wt%) and DW(1 mL) + DG(0.1 mL). The outstanding tribological performances of CNC/2.4-DG/0.1 were reasonably attributed to the synergistic mending effect of CNC and DG and the dissipative effect of H-bonds between the two.

Structure and assembly process of fungal communities in the Yangtze River Estuary

Marine fungi are essential for the ecological function of estuarine ecosystems. However, limited studies have reported on the structure and assembly pattern of the fungal communities in estuaries. The purpose of this study is to reveal the structure and the ecological process of the fungal community in the Yangtze River Estuary (YRE) by using the amplicon sequencing method. Phyla of Ascomycota, Basidiomycota, and Chytridiomycota were dominant in the seawater and sediment samples from YRE. The null model analysis, community-neutral community model (NCM), and phylogenetic normalized stochasticity ratio (pNST) showed that the stochastic process dominated the assembly of fungal communities in YRE. Drift and homogeneous dispersal were the predominant stochastic processes for the fungal community assembly in seawater and sediment samples, respectively. The co-occurrence network analysis showed that fungal communities were more complex and closely connected in the sediment than in the seawater samples. Phyla Ascomycota, Basidiomycota, and Mucoromycota were the potential keystone taxa in the network. These findings demonstrated the importance of stochastic processes for the fungal community assembly, thereby widening our knowledge of the community structure and dynamics of fungi for future study and utilization in the YRE ecosystem.

The succession of epiphytic microalgae conditions fungal community composition: how chytrids respond to blooms of dinoflagellates

This study aims to investigate the temporal dynamics of the epiphytic protist community on macroalgae, during the summer months, with a specific focus on fungi, and the interactions between zoosporic chytrid parasites and the proliferation of the dinoflagellates. We employed a combination of environmental sequencing techniques, incubation of natural samples, isolation of target organisms and laboratory experiments. Metabarcoding sequencing revealed changes in the dominant members of the epiphytic fungal community. Initially, fungi comprised < 1% of the protist community, mostly accounted for by Basidiomycota and Ascomycota, but with the emergence of Chytridiomycota during the mature phase of the biofilm, the fungal contribution increased to almost 30%. Chytridiomycota became dominant in parallel with an increase in the relative abundance of dinoflagellates in the community. Microscopy observations showed a general presence of chytrids following the peak proliferation of the dinoflagellate Ostreopsis sp., with the parasite, D. arenysensis as the dominant chytrid. The maximum infection prevalence was 2% indicating host-parasite coexistence. To further understand the in-situ prevalence of chytrids, we characterised the dynamics of the host abundance and prevalence of chytrids through co-culture. These laboratory experiments revealed intraspecific variability of D. arenysensis in its interaction with Ostreopsis, exhibiting a range from stable coexistence to the near-extinction of the host population. Moreover, while chytrids preferentially parasitized dinoflagellate cells, one of the strains examined displayed the ability to utilize pollen as a resource to maintain its viability, thus illustrating a facultative parasitic lifestyle. Our findings not only enrich our understanding of the diversity, ecology, and progression of epiphytic microalgal and fungal communities on Mediterranean coastal macroalgae, but they also shed light on the presence of zoosporic parasites in less-explored benthic habitats.

Metatranscriptomics and metabarcoding reveal spatiotemporal shifts in fungal communities and their activities in Chinese coastal waters

Fungal communities are diverse and abundant in coastal waters, yet, their ecological roles and adaptations remain largely unknown. To address these gaps, ITS2 metabarcoding and metatranscriptomic analyses were used to capture the whole suite of fungal diversity and their metabolic potential in water column and sediments in the Yellow Sea during August and October 2019. ITS2 metabarcoding described successfully the abundance of Dikarya during August and October at the different examined habitats, but strongly underrepresented or failed to identify other fungal taxa, including zoosporic and early-diverging lineages, that were abundant in the mycobiome as uncovered by metatranscriptomes. Metatranscriptomics also revealed enriched expression of genes annotated to zoosporic fungi (e.g., chytrids) mainly in the surface water column in October. This enriched expression was correlated with the two-fold increase in chlorophyll-a intensity attributed to phytoplanktonic species which are known to be parasitized by chytrids. The concurrent high expression of genes related to calcium signalling and GTPase activity suggested that these metabolic traits facilitate the parasitic lifestyle of chytrids. Similarly, elevated expression of phagosome genes annotated to Rozellomycota, an early-diverging fungal phylum not fully detected with ITS2 metabarcoding, suggested that this taxon utilizes a suite of feeding modes, including phagotrophy in this coastal setting. Our data highlight the necessity of using combined approaches to accurately describe the community structure of coastal mycobiome. We also provide in-depth insights into the fungal ecological roles in coastal waters, and report potential metabolic mechanisms utilized by fungi to cope with environmental stresses that occur during distinct seasonal months in coastal ecosystems.

Impact of environmental factors on diversity of fungi in sediments from the Shenzhen River Estuary

In this study, to explore the relationship between environmental factors and fungal diversity in the Shenzhen River ecosystem, multiple methods including chemical analysis, culture isolation, qPCR analysis of fungal ITS region and ITS-based Illumina next-generation-sequencing were integrated. A total of 115 isolates were finally isolated and could be classified into 23 genera. Top three abundant genera isolated were Meyerozyma (18 strains), Aspergillus (17 strains) and Penicillium (14 strains). Based on the Illumina sequencing approach, 829 OTUs were affiliated to seven phyla, 17 known classes, and 162 genera, indicating the Shenzhen estuary sediments are rich in fungal diversity. The major fungal genera were Meyerozyma, Trichoderma and Talaromyces. Environmental factors showed a gradient change in Shenzhen estuary, and fungal abundance was only significantly correlated with NH₄⁺. Shannon index was significantly correlated with pH and IC (P < 0.05). Principal coordinate analysis based on OTU level grouped into three clusters among sampling sites along with the IC and pH gradient. Functional guilds analysis suggests most of the fungi in this studying area were almost all saprotrophs, suggesting a large number of saprophytic fungi may play a significant role in the organic matter decomposition and nutrient cycling process. In summary, this study will deepen our understanding of fungi community in Shenzhen River ecosystem and their distribution and potential function shaped by environmental factors.

Community assembly patterns and processes of microbiome responses to habitats and Mytilopsis sallei invasion in the tidal zones of the Pearl River Estuary

The sustainability of estuarine ecosystem functions depends on the stabilization of microbial ecological processes. However, due to the unique and variable habitat characteristics of estuarine areas, in-depth studies on ecological processes such as the spatial distribution and assembly patterns of microbial community structure are lacking. As methods to elucidate this structure, we used 16S rDNA, 18S rDNA and ITS sequencing technologies to study the composition, diversity, spatial pattern and aggregation mechanism of the bacterial, protist and fungal communities in the tidal zones of the Pearl River Estuary (PRETZ). The abundance of bacterial communities was much higher than that of protists and fungi, and the spatial pattern was obvious in PRETZ. The application of neutral and null models revealed the assembly process of three microbial communities dominated by stochastic processes. Among the stochastic processes, undominated processes (64.03 %, 62.45 %, and 59.29 %) were the most critical processes in the assembly of bacterial, fungal and protist communities. Meanwhile, environmental variables, geographic locations, and biological factors were associated with the composition and assembly of bacterial, protist, and fungal communities. Among the environmental variables, dissolved oxygen and salinity were the main predictors that jointly affected the differences in the community structure of the three microorganisms, and geographic location was the second predictor affecting the community structure of the three microorganisms and had a more pronounced effect on the diversity and network structure of the bacterial and fungal communities. However, biological factors exerted a weaker effect on the microbial community structure than spatial factors and only affected bacteria and protists; the invasive species Mytilopsis sallei only affected the process of protist community assembly. In addition, environmental variables affected the relative importance of stochastic processes. In summary, the formation of microbial communities in the PRETZ was affected by random processes, environmental variables, geographic location, and invasive species.

Diversity, Abundance, and Ecological Roles of Planktonic Fungi in Marine Environments

Fungi are considered terrestrial and oceans are a “fungal desert”. However, with the considerable progress made over past decades, fungi have emerged as morphologically, phylogenetically, and functionally diverse components of the marine water column. Although their communities are influenced by a plethora of environmental factors, the most influential include salinity, temperature, nutrients, and dissolved oxygen, suggesting that fungi respond to local environmental gradients. The biomass carbon of planktonic fungi exhibits spatiotemporal dynamics and can reach up to 1 μg CL⁻¹ of seawater, rivaling bacteria on some occasions, which suggests their active and important role in the water column. In the nutrient-rich coastal water column, there is increasing evidence for their contribution to biogeochemical cycling and food web dynamics on account of their saprotrophic, parasitic, hyper-parasitic, and pathogenic attributes. Conversely, relatively little is known about their function in the open-ocean water column. Interestingly, methodological advances in sequencing and omics approach, the standardization of sequence data analysis tools, and integration of data through network analyses are enhancing our current understanding of the ecological roles of these multifarious and enigmatic members of the marine water column. This review summarizes the current knowledge of the diversity and abundance of planktonic fungi in the world’s oceans and provides an integrated and holistic view of their ecological roles.

Antarctic Glacial Meltwater Impacts the Diversity of Fungal Parasites Associated With Benthic Diatoms in Shallow Coastal Zones

Aquatic ecosystems are frequently overlooked as fungal habitats, although there is increasing evidence that their diversity and ecological importance are greater than previously considered. Aquatic fungi are critical and abundant components of nutrient cycling and food web dynamics, e.g., exerting top-down control on phytoplankton communities and forming symbioses with many marine microorganisms. However, their relevance for microphytobenthic communities is almost unexplored. In the light of global warming, polar regions face extreme changes in abiotic factors with a severe impact on biodiversity and ecosystem functioning. Therefore, this study aimed to describe, for the first time, fungal diversity in Antarctic benthic habitats along the salinity gradient and to determine the co-occurrence of fungal parasites with their algal hosts, which were dominated by benthic diatoms. Our results reveal that Ascomycota and Chytridiomycota are the most abundant fungal taxa in these habitats. We show that also in Antarctic waters, salinity has a major impact on shaping not just fungal but rather the whole eukaryotic community composition, with a diversity of aquatic fungi increasing as salinity decreases. Moreover, we determined correlations between putative fungal parasites and potential benthic diatom hosts, highlighting the need for further systematic analysis of fungal diversity along with studies on taxonomy and ecological roles of Chytridiomycota.

Basal Parasitic Fungi in Marine Food Webs-A Mystery Yet to Unravel

Although aquatic and parasitic fungi have been well known for more than 100 years, they have only recently received increased awareness due to their key roles in microbial food webs and biogeochemical cycles. There is growing evidence indicating that fungi inhabit a wide range of marine habitats, from the deep sea all the way to surface waters, and recent advances in molecular tools, in particular metagenome approaches, reveal that their diversity is much greater and their ecological roles more important than previously considered. Parasitism constitutes one of the most widespread ecological interactions in nature, occurring in almost all environments. Despite that, the diversity of fungal parasites, their ecological functions, and, in particular their interactions with other microorganisms remain largely speculative, unexplored and are often missing from current theoretical concepts in marine ecology and biogeochemistry. In this review, we summarize and discuss recent research avenues on parasitic fungi and their ecological potential in marine ecosystems, e.g., the fungal shunt, and emphasize the need for further research.

High-Level Diversity of Basal Fungal Lineages and the Control of Fungal Community Assembly by Stochastic Processes in Mangrove Sediments

Fungi are key components of microbial communities in mangrove wetlands, with important roles in the transformation of nutrients and energy. However, existing studies typically focus on cultivable fungi and seldom on the structure and driving factors of entire fungal communities. The compositions, community assembly, and interaction patterns of mangrove fungal communities on a large scale remain elusive. Here, biogeography, assembly, and co-occurrence patterns of fungal communities in mangroves across eastern to southern China were systematically analyzed by targeting the entire internal transcribed spacer (ITS) region with high-throughput Pacific Biosciences single-molecule real-time sequencing. The analysis revealed a high level of fungal diversity, including a number of basal fungal lineages not previously reported in mangroves, such as Rozellomycota and Chytridiomycota. Beta nearest-taxon index analyses suggested a determinant role of dispersal limitation on fungal community in overall and most individual mangroves, with support from the strong distance-decay patterns of community similarity. Further, nonmetric multidimensional scaling analyses revealed similar biogeographies of dominant and rare fungal communities. A minor role of environmental selection on the fungal community was noted, with geographical location and sediment depth as crucial factors driving the distribution of both, the dominant and rare taxa. Finally, network analysis revealed high modularized co-occurrence patterns of fungal community in mangrove sediments, and the keystone taxa might play important roles in microbial interactions and ecological functions. The investigation expands our understanding of biogeography, assembly patterns, driving factors, and co-occurrence relationships of mangrove fungi and will spur the further functional exploration and protection of fungal resources in mangroves. IMPORTANCE As key components of microbial community in mangroves, fungi have important ecological functions. However, the fungal community in mangroves on a large scale is generally elusive, and mangroves are declining rapidly due to climate change and anthropogenic activities. This work provides an overview of fungal community structure and biogeography in mangrove wetlands along a >9,000-km coastline across eastern to southern China. Our study observed a high number of basal fungal lineages, such as Rozellomycota and Chytridiomycota, in mangrove sediments. In addition, our results highlight a crucial role of dispersal limitation and a minor role of environmental selections on fungal communities in mangrove sediments. These novel findings add important knowledge about the structure, assembly processes, and driving factors of fungal communities in mangrove sediments.

Microbial Communities' Characterization in Urban Recreational Surface Waters Using Next Generation Sequencing

Microbial communities in surface waters used for recreational purposes are indicators of contamination and risk of contact with human pathogens. Hence, monitoring microbial communities in recreational waters is important for potential public health threats to humans. Such monitoring is rare in Colombia, even in its capital, Bogotá, the most populous city in the country. This city encompasses metropolitan and linear parks with recreational water bodies that are used frequently by the public, and the presence of pathogens can compromise the health of the citizens. Therefore, we examined the bacterial, and eukaryotic communities in urban recreational lakes (URL) in four metropolitan parks in Bogotá, Colombia. Samples from four metropolitan parks (Los Novios, Simon Bolivar, El Tunal, and Timiza) and one stream contaminated with sewage from a linear park (El Virrey) were collected. We used amplicon next-generation sequencing of the 16S-rRNA gene and 18S-rRNA gene to characterize microbial communities followed by bioinformatics analyses. In addition, general water quality parameters-pH, hardness, acidity, alkalinity, dissolved oxygen, and nitrites-were recorded using a commercial kit. Genera of pathogens, including Legionella, Pseudomonas, Mycobacterium, Candida, and Naegleria, were found in lake waters. The stream El Virrey was, however, the only surface water that showed an abundance of fecal bacteria, often associated with low oxygen concentrations. All water bodies showed a predominance of fungal phyla, except for the lake at Timiza. This lake showed the highest pH, and its ecological dynamics are likely different from other water bodies. Likewise, some URLs displayed a greater abundance of cyanobacteria, including toxin-producing species. Algal genera associated with eutrophication were predominant among primary producing microorganisms. This study shows for the first time the description of the bacterial and eukaryotic communities of some URLs and a stream in Bogotá. The URLs and the stream harbored various pathogens that might pose a risk to the citizen's health.

Bacterial communities are more sensitive to ocean acidification than fungal communities in estuarine sediments

Ocean acidification (OA) in estuaries is becoming a global concern, and may affect microbial characteristics in estuarine sediments. Bacterial communities in response to acidification in this habitat have been well discussed; however, knowledge about how fungal communities respond to OA remains poorly understood. Here, we explored the effects of acidification on bacterial and fungal activities, structures and functions in estuarine sediments during a 50-day incubation experiment. Under acidified conditions, activities of three extracellular enzymes related to nutrient cycling were inhibited and basal respiration rates were decreased. Acidification significantly altered bacterial communities and their interactions, while weak alkalization had a minor impact on fungal communities. We distinguished pH-sensitive/tolerant bacteria and fungi in estuarine sediments, and found that only pH-sensitive/tolerant bacteria had strong correlations with sediment basal respiration activity. FUNGuild analysis indicated that animal pathogen abundances in sediment were greatly increased by acidification, while plant pathogens were unaffected. High-throughput quantitative PCR-based SmartChip analysis suggested that the nutrient cycling-related multifunctionality of sediments was reduced under acidified conditions. Most functional genes associated with nutrient cycling were identified in bacterial communities and their relative abundances were decreased by acidification. These new findings highlight that acidification in estuarine regions affects bacterial and fungal communities differently, increases potential pathogens and disrupts bacteria-mediated nutrient cycling.

Disentangling the structure and function of mycoplankton communities in the context of marine environmental heterogeneity

Mycoplankton are a diverse and ubiquitous component of marine environments with a suggested role in ocean biogeochemical cycling. Thus far, the patterns of their abundance, structure, and function against spatial environmental heterogeneity remains poorly understood. Based on in silico and experimental evaluation of multiple markers, we adopted the ITS1 region to determine the composition, guilds, and metabolic potential of mycoplankton communities in contrasting marine environments. The trophic status of estuarine (SB1 and SB2) and coastal (DB1 and DB2) sites, but not oceanic (OS) site, was the major factor that determined their abundances. While ascomycetous fungi dominated the estuarine and coastal sites, basidiomycetous fungi were found to dominate the oceanic site. The zoosporic fungi were relatively more abundant in SB1 and DB2 sites compared to the other sites. The relative abundances of the core fungi, namely Cystobasidium, Phlebia, Rhodotorula, Trichoderma, Alternaria, Penicillium, Malassezia, and Aspergillus varied widely across the sites. Additionally, several fungal genera unique to each site were also identified. DB2 site exhibited the lowest fungal richness while the OS site the highest. Conversely, the diversity and evenness were the lowest for the OS site but highest for the SB1 site. Temperature, pH, and chlorophyll-a were strongly associated with spatial diversity patterns. Of the 11 assigned guilds, some guilds particularly were not detected, including plant pathogen-wood saprotroph in DB2, the endophyte-plant pathogen in OS, the animal pathogen in SB1, and fungal parasite in DB1 and SB2. Within core functions-metabolism of amino acids, carbohydrates and energy, fatty acids and lipids, nitrogen, sulfur, and other compounds-several pathways showed spatial variations. Overall, this study not just broadens the taxonomic and metabolic repertoire of marine mycoplankton but also provides the first evidence of how these are shaped by site-scale environmental heterogeneity.

Fungi in aquatic ecosystems

Fungi are phylogenetically and functionally diverse ubiquitous components of almost all ecosystems on Earth, including aquatic environments stretching from high montane lakes down to the deep ocean. Aquatic ecosystems, however, remain frequently overlooked as fungal habitats, although fungi potentially hold important roles for organic matter cycling and food web dynamics. Recent methodological improvements have facilitated a greater appreciation of the importance of fungi in many aquatic systems, yet a conceptual framework is still missing. In this Review, we conceptualize the spatiotemporal dimensions, diversity, functions and organismic interactions of fungi in structuring aquatic food webs. We focus on currently unexplored fungal diversity, highlighting poorly understood ecosystems, including emerging artificial aquatic habitats.

Fungal and bacterial diversity of Svalbard subglacial ice

The composition of fungal and bacterial communities in three polythermal glaciers and associated aquatic environments in Kongsfjorden, Svalbard was analysed using a combination of cultivation and amplicon sequencing. 109 fungal strains belonging to 30 mostly basidiomycetous species were isolated from glacial samples with counts up to 10³ CFU/100 ml. Glaciozyma-related taxon and Phenoliferia psychrophenolica were the dominant species. Unexpectedly, amplicon sequencing uncovered sequences of Chytridiomycota in all samples and Rozellomycota in sea water, lake water, and tap water. Sequences of Malassezia restricta and of the extremely halotolerant Hortaea werneckii were also found in subglacial habitats for the first time. Overall, the fungal communities within a glacier and among glaciers were diverse and spatially heterogenous. Contrary to this, there was a large overlap between the bacterial communities of different glaciers, with Flavobacterium sp. being the most frequently isolated. In amplicon sequencing Actinobacteria and Proteobacteria sequences were the most abundant.

A Salinity Threshold Separating Fungal Communities in the Baltic Sea

Salinity is a significant factor for structuring microbial communities, but little is known for aquatic fungi, particularly in the pelagic zone of brackish ecosystems. In this study, we explored the diversity and composition of fungal communities following a progressive salinity decline (from 34 to 3 PSU) along three transects of ca. 2000 km in the Baltic Sea, the world's largest estuary. Based on 18S rRNA gene sequence analysis, we detected clear changes in fungal community composition along the salinity gradient and found significant differences in composition of fungal communities established above and below a critical value of 8 PSU. At salinities below this threshold, fungal communities resembled those from freshwater environments, with a greater abundance of Chytridiomycota, particularly of the orders Rhizophydiales, Lobulomycetales, and Gromochytriales. At salinities above 8 PSU, communities were more similar to those from marine environments and, depending on the season, were dominated by a strain of the LKM11 group (Cryptomycota) or by members of Ascomycota and Basidiomycota. Our results highlight salinity as an important environmental driver also for pelagic fungi, and thus should be taken into account to better understand fungal diversity and ecological function in the aquatic realm.

Fungi in the Marine Environment: Open Questions and Unsolved Problems

Terrestrial fungi play critical roles in nutrient cycling and food webs and can shape macroorganism communities as parasites and mutualists. Although estimates for the number of fungal species on the planet range from 1.5 to over 5 million, likely fewer than 10% of fungi have been identified so far. To date, a relatively small percentage of described species are associated with marine environments, with ∼1,100 species retrieved exclusively from the marine environment. Nevertheless, fungi have been found in nearly every marine habitat explored, from the surface of the ocean to kilometers below ocean sediments. Fungi are hypothesized to contribute to phytoplankton population cycles and the biological carbon pump and are active in the chemistry of marine sediments. Many fungi have been identified as commensals or pathogens of marine animals (e.g., corals and sponges), plants, and algae. Despite their varied roles, remarkably little is known about the diversity of this major branch of eukaryotic life in marine ecosystems or their ecological functions. This perspective emerges from a Marine Fungi Workshop held in May 2018 at the Marine Biological Laboratory in Woods Hole, MA. We present the state of knowledge as well as the multitude of open questions regarding the diversity and function of fungi in the marine biosphere and geochemical cycles.

Molecular Detection of Eukaryotic Diets and Gut Mycobiomes in Two Marine Sediment-Dwelling Worms, Sipunculus nudus and Urechis unicinctus

The present study aimed to reveal the eukaryotic diets of two economically important marine sediment-inhabiting worms, Sipunculus nudus (peanut worm) and Urechis unicinctus (spoon worm), using clone libraries and phylogenetic analyses of 18S rRNA genes. Fungal rDNA was also targeted and analyzed to reveal mycobiomes. Overall, we detected a wide range of eukaryotic phylotypes associated with the larvae of S. nudus and in the gut contents of both worms. These phylotypes included ciliates, diatoms, dinoflagellates, eustigmatophytes, placidids, oomycetes, fungi, nematodes, flatworms, seaweeds, and higher plants. Oomycetes were associated with the planktonic larvae of S. nudus. The composition of eukaryotic diets shifted greatly across the larval, juvenile, and adult stages of S. nudus, and among different gut sections in U. unicinctus, reflecting lifestyle changes during the ontogeny of the peanut worm and progressive digestion in the spoon worm. Malassezia-like fungi were prevalent in mycobiomes. Epicoccum and Trichosporon-related phylotypes dominated mycobiomes associated with larval individuals and in the gut contents of adults, respectively. The gut mycobiome of S. nudus was successively characterized through the midgut, aspiratory intestines, hindgut, and rectum as having a high proportion of Climacodon-Rhizochaete, Ceriporiopsis, Cladosporium-Pseudomicrostroma, and Malassezia-related species in the libraries. These results emphasize the dynamics of diets and gut mycobiomes in marine benthic animals.