Microbial Communities in Sunken Wood Are Structured by Wood-Boring Bivalves and Location in a Submarine Canyon

The cornerstones of sunken wood ecosystems are microorganisms involved in cellulose degradation. These can either be free-living microorganisms in the wood matrix or symbiotic bacteria associated with wood-boring bivalves such as emblematic species of Xylophaga, the most common deep-sea woodborer. Here we use experimentally submerged pine wood, placed in and outside the Mediterranean submarine Blanes Canyon, to compare the microbial communities on the wood, in fecal pellets of Xylophaga spp. and associated with the gills of these animals. Analyses based on tag pyrosequencing of the 16S rRNA bacterial gene showed that sunken wood contained three distinct microbial communities. Wood and pellet communities were different from each other suggesting that Xylophaga spp. create new microbial niches by excreting fecal pellets into their burrows. In turn, gills of Xylophaga spp. contain potential bacterial symbionts, as illustrated by the presence of sequences closely related to symbiotic bacteria found in other wood eating marine invertebrates. Finally, we found that sunken wood communities inside the canyon were different and more diverse than the ones outside the canyon. This finding extends to the microbial world the view that submarine canyons are sites of diverse marine life.     

Beetles provide directed dispersal of viable spores of a keystone wood decay fungus

Wood decay fungi are considered to be dispersed by wind, but dispersal by animals may also be important, and more so in managed forests where dead wood is scarce. We investigated whether beetles could disperse spores of the keystone species Fomitopsis pinicola. Beetles were collected on sporocarps and newly felled spruce logs, a favourable habitat for spore deposition. Viable spores (and successful germination) of F. pinicola were detected by dikaryotization of monokaryotic bait mycelium from beetle samples. Viable spores were on the exoskeleton and in the faeces of all beetles collected from sporulating sporocarps. On fresh spruce logs, nine beetle species transported viable spores, of which several bore into the bark. Our results demonstrate that beetles can provide directed dispersal of wood decay fungi. Potentially, it could contribute to a higher persistence of some species in fragmented forests where spore deposition by wind on dead wood is less likely.     

Biodegradation of wood exposed in the marine environment: Evaluation of the hazard posed by marine wood-borers in fifteen European sites

The activity of marine wood-borers causes great destruction in maritime wooden structures. Therefore, the aim of this study was to evaluate the hazard posed by marine wood-borers in fifteen European sites, to assist authorities and researchers concerned with the protection of wood in the sea. In northern Europe, Teredo navalis is the species that poses the highest borer hazard while in the Atlantic coast of southern Europe Lyrodus pedicellatus is the most destructive species, with the exception of two sites in Portugal. In these sites, Limnoria tripunctata was more destructive than L. pedicellatus. In the Mediterranean both T. navalis and L. pedicellatus pose a very high borer hazard to wooden structures.Salinity and temperature emerged as the environmental conditions that best explain the occurrence and abundance of wood boring species in the sites surveyed. Three of the species highlighted in this study are warm water species. Therefore their activity might increase in the future, due to global warming. Considering that wood is still a very valuable material for construction, its use for maritime construction should be favoured. Thus research to improve the durability of wooden materials in the marine environment is of paramount importance.     

Revision of Dicorynia (Cassieae,Caesalpiniaceae)

A combined taxonomic revision and wood anatomical study ofDicorynia, a South American genus of legumes that is unusual in both its floral and wood anatomy, is presented. Two possible evolutionary pathways leading to the unique 8-to 10-thecate anthers are discussed, and it is concluded that apical proliferation of the thecal primordia is the more likely. Gross and microscopic features of this silica-accumulating wood are given in detail and contrasted with other legume woods especially those containing silica. Economic uses of the trees, especially the wood ofD. guianensis, are discussed particularly in regard to marine construction. It is suggested that the high resistance of this wood to marine borers lies not so much in its silica content as to the presence of some other chemical. Based on the similarity of floral and fruit structures, the number of species is reduced from 7 to 2:D. guianensis in the Guianas andD. paraensis in the Amazonian region. Vegetative variations in the Amazonian population, previously given species rank, are reduced to 5 new varieties ofD. paraensis.     

山东海岸木生海洋真菌的研究I.(英文)

为调查中国黄海海域的丝状海洋真菌,从山东威海潮间带海滩收集了沉没木、附着木和沙埋木,并从其上分离到7种高等海洋真菌。Arenariomycestrifurcata,Corollosporamaritima,Alternariamaritima,Trichocladiumachrasporum为中国大陆新记录种,Chaetomiunglobosum,Tetraploaaristata,Torulasp.为中国大陆新生境报道。对每个种作了描述并对分类和形态进行了讨论。     

A laboratory assay for measuring feeding and mortality of the marine wood borer Limnoria under forced feeding conditions: A basis for a standard test method

Quick simple testing methods are needed to evaluate alternative wood materials for marine construction because traditional borer resistant materials are becoming scarce or are no longer permitted due to concerns over environmental emissions of preservatives. Laboratory tests can provide species-specific information on rates of wood biodeterioration by wood borers under optimum conditions, in contrast to field trials where more than one borer species may be present and conditions are variable.The methodology described herein relies on the assumption that faecal pellet production rate in limnoriids must match feeding rate quite closely. Thus, the number of faecal pellets produced by individual specimens of Limnoria quadripunctata, while feeding on a non-durable and non-toxic wood species – Pinus sylvestris sapwood – in different test conditions, was monitored over a period of 15 days. Mortality and moulting were also registered. Several variables likely to affect survival and feeding rates were investigated in order to optimise the test conditions. Temperature and salinity regime affected both survival and feeding rates while moulting cycle affected feeding rates.The optimisation of this test methodology aims to provide the basis for a standard laboratory test with the wood-boring crustacean Limnoria.     

Colonization and substratum preference of an introduced burrowing crustacean in a temperate estuary

Habitat use in marine invertebrates is often influenced by multiple abiotic and biotic factors. Substratum composition is one factor known to have a dramatic effect on habitat selection. The Australasian burrowing isopod (Sphaeroma quoianum, H. Milne Edwards 1840) is a common introduced species in many estuaries on the Pacific coast of North America. S. quoianum burrows into a variety of firm substrata including marsh banks (composed of peat, clay, and/or mud), wood, friable rock, and Styrofoam floats. In some areas, isopods achieve high densities and may accelerate the rate of shoreline erosion and damage marine structures; thus, understanding the substratum preference of this species may be important for conservation and management efforts. Field experiments were conducted in Coos Bay, Oregon to examine substratum preference, burrowing rates, and the life stage of colonizers. In three experimental trials (Fall 2005, Spring 2006, Fall 2006), replicates of four intertidal substrata (marsh banks, decayed wood, sandstone, Styrofoam) were deployed near intertidal populations of S. quoianum. The numbers of burrows created in each substratum were enumerated weekly or daily (depending on trial). After the trials were completed, the total numbers of isopods inhabiting each substratum were counted. In weeks, S. quoianum extensively burrowed the substrata but exhibited a distinct preference for decayed wood. Significantly more isopods were present in wood than the other substrata at the end of the experiments and rates of burrowing were greatest in wood, although significance varied across time in one trial. Nearly 90% of colonizing isopods were under 5 mm in length suggesting that juvenile isopods primarily colonize intertidal substrata. Differences between burrow densities measured in the field and the results from these preference trials may indicate other factors, such as relative availability of substrata, recruitment and dispersal limitations, and possible gregarious behavior also influence local isopod densities.     

Ecological observations on marine fungi from the Seychelles

HYDE, K. D. & JONES, E. 6. G., 1989. Ecological observations on marine fungi from the Seychelles . Submerged wood, wood trapped amongst rocks, sand-buried wood and exposed roots and branches of shoreline trees were collected from three intertidal beach sites in the Seychelles. These were examined for the presence of marine fungi, the species present identified and their frequency of occurrence noted. Leaves, seaweeds and seagrasses washed up on the seashore, and seafoam, were also examined for filamentous marine fungi. Species present are listed with their frequency of occurrence. Differences in species composition from one substratum to the next were noted, and the results discussed. Sixty-three species were collected: 35 Ascomycotina, 2 Basidiomycotina and 26 Deuteromycotina, all are new records for the Seychelles. The mycogeography and ecological niche of the fungi encountered are discussed.     

Marine fungal lineages in the Hypocreomycetidae

Phylogenetic analyses of DNA sequences from protein coding and ribosomal nuclear loci support the placement of a number of marine fungal species associated with a well-supported clade containing fungicolous species of Melanospora and wood inhabiting Coronophorales. Three subclades containing marine species were recovered including Torpedospora radiata plus T. ambispinosa, Swampomyces species plus Juncigena adarca, and two Etheirophora species plus additional Swampomyces species. The monophyly of these three subclades, as well as a subclade containing representatives of Coronophorales and Melanospora, is well supported statistically. However, relationships among the different subclades remain largely unresolved. A sister relationship for this group with Hypocreales is significantly supported by Bayesian and ML methods. In addition to the Halospheariales and Lulworthiales, this clade, which is characterized by considerable morphological and ecological diversity, represents a third major clade of marine Sordariomycetes.     

Microbial Distribution and Abundance in the Digestive System of Five Shipworm Species (Bivalvia: Teredinidae)

Marine bivalves of the family Teredinidae (shipworms) are voracious consumers of wood in marine environments. In several shipworm species, dense communities of intracellular bacterial endosymbionts have been observed within specialized cells (bacteriocytes) of the gills (ctenidia). These bacteria are proposed to contribute to digestion of wood by the host. While the microbes of shipworm gills have been studied extensively in several species, the abundance and distribution of microbes in the digestive system have not been adequately addressed. Here we use Fluorescence In-Situ Hybridization (FISH) and laser scanning confocal microscopy with 16S rRNA directed oligonucleotide probes targeting all domains, domains Bacteria and Archaea, and other taxonomic groups to examine the digestive microbiota of 17 specimens from 5 shipworm species (Bankia setacea, Lyrodus pedicellatus, Lyrodus massa, Lyrodus sp. and Teredo aff. triangularis). These data reveal that the caecum, a large sac-like appendage of the stomach that typically contains large quantities of wood particles and is considered the primary site of wood digestion, harbors only very sparse microbial populations. However, a significant number of bacterial cells were observed in fecal pellets within the intestines. These results suggest that due to low abundance, bacteria in the caecum may contribute little to lignocellulose degradation. In contrast, the comparatively high population density of bacteria in the intestine suggests a possible role for intestinal bacteria in the degradation of lignocellulose.     

Fossil wood of Piceoxylon burejense sp. nov. (Pinaceae) from the Upper Cretaceous of Zeya-Bureya Basin, Amur Region (Russian Far East)

A new species, Piceoxylon burejense sp. nov. (Pinaceae), is described from the Middle Maastrichtian (Upper Cretaceous) of the Zeya-Bureya Basin, Amur Region (Russian Far East) based on the fossil wood anatomy. The new species is characterized by a combination of anatomical wood features of the modern genera Picea and Larix. The fossil wood of Pinaceae was found in the Cretaceous deposits of the Amur Region for the first time.     

Some lignicolous marine fungi from Sri Lanka

Koch, J. 1982. Some lignicolous marine fungi from Sri Lanka. – Nord. J. Bot. 2 : 163–169. Copenhagen. ISSN 0107–055X.
Twenty–seven marine fungi are reported from intertidal wood collected in the Indian Ocean at Sri Lanka. One new genus Nimbospora and two new species Nimbospora effusa and Halosarpheia bentotensis are described. A new combination Savoryella paucispora is proposed. Obervations are presented on some poorly known and interesting species.     

Comparative study on the delignification of Azadirachta indica (L) Del., wood by Chrysosporium asperatum and Trichoderma harzianum

Structural alterations induced in response to degradation by two white rot Basidiomycetes on the secondary xylem of Azadirachta indica (L) Del., was compared. In vitro decay test was employed to investigate the pattern of delignification of Azadirachta wood by Trichoderma harzianum and Chrysosporium asperatum. Wood samples inoculated with both the strains were analyzed for different periods viz. 30, 60, 90 and 120 days after fungal inoculation. Initially there was no appreciable percent weight loss of the wood blocks but later on (after 60 days) it increased rapidly and was found similar for both the strains (43-46% of wood mass). Samples inoculated with both the strains showed dual pattern of degradation i.e. selective delignification in the initial stage followed by simultaneous rot during advance stage of decay. Separation of the cells due to dissolution of middle lamella was the characteristic feature of both strains but in the advanced stage of decay, formation of erosion troughs were conspicuous in all the cell types. Other features such as cell wall thinning, rounded pit erosion, formation of erosion channels and bore holes were also observed frequently. Initially, fungal invasion started through the vessel lumen, followed by all the cell types of the xylem. From the vessels, mycelia entered into the adjacent rays and parenchyma cells through the pits. In advanced stage, degradation was so pronounced that rays were partially or even completely destroyed while many cells including vessels were either deformed or destroyed due to loss of rigidity of their walls. Structural alterations induced in response to C. asperatum and T. harzianum attack is described in details.     

External Microflora of a Marine Wood-Boring Isopod

Bacteria associated with the marine wood-boring isopod Limnoria lignorum were enumerated by acridine orange epifluorescence microscopy and by plate counts on several media; the plate-viable bacteria were isolated and identified. Similar procedures were followed to enumerate and identify bacteria associated with the wood substrate from which the isopods were collected and with the surrounding water from the isopod habitat. Approximately 1.4 × 10⁷ bacterial cells were associated with each individual L. lignorum. Aeromonas hydrophila, Pseudomonas, and Vibrio were the most common genera in the isopod microflora. Wood from L. lignorum burrows had an associated bacterial flora of 1.6 × 10⁷ cells per mg (damp weight). A. hydrophila also predominated in the wood microflora. The water from which the isopod population was collected contained 2.3 × 10⁶ bacteria per ml. Pseudomonas and Vibrio species were very common in the water microflora, but A. hydrophila was not detected. Interactions between the isopod, its associated microorganisms, and the microorganisms within the wood substrate are discussed in the light of the known absence of a resident digestive tract microflora in these animals.     

New Insights on Wood Dimensional Stability Influenced by Secondary Metabolites: The Case of a Fast-Growing Tropical Species Bagassa guianensis Aubl.

Challenging evaluation of tropical forest biodiversity requires the reporting of taxonomic diversity but also the systematic characterization of wood properties in order to discover new promising species for timber industry. Among wood properties, the dimensional stability is regarded as a major technological characteristic to validate whether a wood species is adapted to commercial uses. Cell structure and organization are known to influence the drying shrinkage making wood density and microfibrils angle markers of choice to predict wood dimensional stability. On the contrary the role of wood extractive content remains unclear. This work focuses on the fast-growing tropical species Bagassa guianensis and we report herein a correlation between heartwood drying shrinkage and extractive content. Chemical extractions and shrinkage experiments were performed on separate wood twin samples to better evaluate correctly how secondary metabolites influence the wood shrinkage behaviour. Extractive content were qualitatively and quantitatively analysed using HPLC and NMR spectroscopy. We found that B guianensis heartwood has a homogeneous low shrinkage along its radius that could not be explained only by its basic density. In fact the low drying shrinkage is correlated to the high extractive content and a corrected model to improve the prediction of wood dimensional stability is presented. Additionally NMR experiments conducted on sapwood and heartwood extracts demonstrate that secondary metabolites biosynthesis occurs in sapwood thus revealing B. guianensis as a Juglans-Type heartwood formation. This work demonstrates that B. guianensis, a fast-growing species associated with high durability and high dimensional stability, is a good candidate for lumber production and commercial purposes.     

Production of New Unsaturated Lipids during Wood Decay by Ligninolytic Basidiomycetes

Lipids were analyzed by gas chromatography-mass spectrometry for a 7-week in vitro decay of eucalypt wood by four ligninolytic basidiomycetes. The sound wood contained up to 75 mg of lipophilic compounds per 100 g of wood. Hydrolysis of sterol esters, which represented 38% of total wood lipids, occurred during the fungal decay. The initial increase of linoleic and other free unsaturated fatty acids paralleled the decrease of sterol esters. Moreover, new lipid compounds were found at advanced stages of wood decay that were identified from their mass spectra as unsaturated dicarboxylic acids consisting of a long aliphatic chain attached to the C-3 position of itaconic acid. These dicarboxylic acids were especially abundant in the wood treated with Ceriporiopsis subvermispora (up to 24 mg per 100 g of wood) but also were produced by Phlebia radiata, Pleurotus pulmonarius, and Bjerkandera adusta. We hypothesize that three main alkylitaconic acids (tetradecylitaconic, cis-7-hexadecenylitaconic, and hexadecylitaconic acids) are synthesized by fungi in condensation reactions involving palmitic, oleic, and stearic acids. We suggest that both wood unsaturated fatty acids (present in free form or released from esters during natural decay) and unsaturated metabolites synthesized by fungi could serve as a source for peroxidizable lipids in lignin degradation by white rot basidiomycetes.     

Rapid destruction of PVC piping by boring bivalves

It is becoming common practise to select plastics such as unplasticised polyvinyl chloride (PVC) for construction of submarine pipes and intakes, especially for service in conditions where wood is susceptible to attack. Recent cases indicate, however, that these materials may not necessarily be immune. Failure of PVC piping on the north coast of Java from attack by boring pholads, Martesia striata, occurred in approximately one year. It appears to be the most rapid yet reported. Destruction by marine borers within one to three years at this and other polluted harbour locations around the world lead us to conclude that eutrophication of the environment from anthropogenic sources can accelerate attack and biodeterioration of marine materials.     

Bivalve Wood Borings of the Ichnogenus Teredolites Leymerie from the Bohemian Cretaceous Basin (Upper Cretaceous,Czech Republic)

Finds of fossil wood with bivalve wood borings (Teredolites clavatus and T. longissimus) occur in various facies and presumed sedimentary settings of the platform, shallow-marine Bohemian Crectaceous Basin. The basin comprises areas with sandy-dominated sediments, with marl and clay-dominated sediments, areas with predominat sandy-marly rocks, and finally areas dominated by calcareous nearshore sediments. Teredolites clavatus is common in fossil wood of sandstones, originating in beach or deltaic settings; marl and clay-dominated rock frequently bear wood fragments densely bored by Teredolites longissimus. When accompanied by evidence of marine environments as body fossils, glauconite or typical trace fossils, most of the wood fragments are bored. The presence/absence of borings in wood fragments can be considered the most reliable and easily useable criterion of distinction of marine settings in sandy sediments of the margin of the Bohemian Cretaceous Basin.     

Fossil wood of Keteleerioxylon kamtschatkiense sp. nov. (Pinaceae) from the Cretaceous of the northwestern Kamchatka Peninsula

A new species, Keteleerioxylon kamtschatkiense, is described from the Cretaceous of the northwestern Kamchatka Peninsula on the basis of wood anatomy. Fossil wood showing anatomical characters of the modern genus Keteleeria is described from the Cretaceous of the Russian Far East for the first time.