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1.
Abstract. A complex and highly unusual eukaryotic microorganism was discovered to be penetrating and removing the periostracum of deep-sea mussels from the Florida Escarpment brine seeps at a depth of 3266 m. These brine seeps support a chemolithoautotrophic redox community similar to those known from Pacific hydrotherma! vents. This microorganism of unknown taxonomic affinity is filamentous and coenocytic, with a simple plasma membrane and no cell wall. It forms prostrate, radiating systems of branched tunnels, 8–15 u.m in diameter. The surface of the tunnels is sculptured by helically organized, scale-like depressions, which are left as scars in the process of periostracum removal by the organism. Periostracum is removed in discrete pieces (scallops) at the ends of the tunnels. This organism has been found at three Atlantic deep-sea redox communities, but not in similar communities of the Pacific. 相似文献
2.
几丁质是贝类贝壳的重要组成成分,在贝壳形成和生物矿化中具有重要作用。本研究通过对厚壳贻贝的贝壳和外套膜边缘三层褶皱进行形态和组织学观察,发现贻贝角质层壳膜是从外褶皱和中褶皱之间的壳膜沟中分泌,而外套膜三层褶皱间组织形态、细胞类型都存在较大差异。此外,本研究还从厚壳贻贝的角质层和贝壳层中提取并鉴定到β-几丁质成分,并构建了外套膜内褶皱（IF）、中褶皱（MF）、外褶皱（OF）的转录组文库,筛查出几丁质合成、降解、结合相关功能的三类几丁质相关基因,对其结构域和表达模式进行进一步分析,发现几丁质合成酶基因以及β氨基己糖苷酶、二-N-乙酰壳二糖酶等几丁质酶基因主要在内、中褶皱表达,而壳三糖苷酶类的几丁质酶基因和几丁质结合蛋白基因则主要在外褶皱表达。在三褶皱差异表达基因的GO富集分析中,进一步发现内、中褶皱主要参与几丁质的生物合成,而外褶皱则主要参与调控几丁质结合、代谢、角质层色素沉着等过程。本研究揭示了外套膜三褶皱在几丁质合成、代谢、结合等功能方面的差异,其中外褶皱可能在厚壳贻贝的贝壳角质层的形成和色素沉着中发挥更重要的作用。本研究有助于了解贻贝贝壳中的几丁质成分以及几丁质相关基因,为软体动物贝... 相似文献
3.
Wood destruction in test panels ofShorea leprosulawas related to the percentage of fouling, types of wood borers and the number of wood borers. The natural durability ofShorea leprosulapanels was estimated to be 4–5 months in Malaysian marine waters. A higher fouling cover resulted in lower rates of wooden panel deterioration. Larger numbers of wood borers brought about greater panel deterioration. Primary wood destruction was caused by bivalve wood borers, mainlyMartesia striata, Lyrodus pedicellatus, Bankia campanellata, Teredo furciferaandTeredo bartschi. Martesia striatawas the important wood destroying agent in the intertidal zone and, together with the shipworms, was also responsible for panel destruction in the subtidal zone. 相似文献
4.
A. G. Beu 《新西兰海洋与淡水研究杂志》2013,47(3):445-452
The tonnacean genus Thalassocyon Barnard, 1960 contains only two species, T. bonus Barnard, 1960 from deep water off South Africa and T. mi Dell, 1967 from deep water off northern New Zealand. The genus is removed from the Cymatiidae and placed in the Ficidae on the basis of shell morphology, the reduced periostracum and the details of the radula. 相似文献
5.
Mussel Periostracum from Deep-Sea Redox Communities as a Microbial Habitat: 3. Secondary Inhabitants
Abstract. Vacated microborings in periostracum of live mussels of the Florida Escarpment redox community (depth of 3266 m) become a habitat for a prolific secondary microbiota consisting of a variety of prokaryotic and a few eukaryotic organisms. Periostracum surface is also colonized by diverse microorganisms, dominated by presumed chemolithotrophic bacteria with stacks of intracellular lamellae. Unlike sheltered microflora within borings, the surface community is heavily grazed upon by numerous archaeogastropods and ciliates. 相似文献
6.
Variations in the mineralogy and chemistry of the shells of the filter-feeding organism Mytilus edulis have allowed discrimination of subenvironments of growth within the Tay estuary. Aragonite proportions higher than those predictable for the temperate, tidal, growth conditions are associated with stretches of the estuary affected by organic pollution. Accumulation and concentration of copper (Cu) in the organic periostracum suggest that Mytilus shell may also prove useful as a monitor of metallic element pollution.The relatively fragile nature of the polylayer shell of Mytilus and the layer specific distribution of components require the use of either complete, undamaged specimens or population groups to discriminate significant variations. 相似文献
7.
国内外贝类学界都认为贝壳角质层仅由贝壳素构成.棱柱层由方解石构成.珍珠层通常为霰石构成.日本的小林新二郎提出棱柱珍珠是方解石结构,国内外许多论文对此都没有提出异议.本研究采用X-射线对贝壳和棱柱珍珠衍射结果证明:(1)贝壳珍珠层全是是霰石结构,只有牡蛎(Ostrea rivularis)壳例外,符合以上理论;(2)棱柱层几乎全是霰石结构,只有牡蛎壳和紫色裂江珧(Pinna atropurpurea)壳的棱柱层是方解石结构,基本否定了以上理论;(3)角质层由有机物—贝壳素和方解石或霰石组成的,有些还含二氧化硅等杂质,这不完全相符上面理论;(4)棱柱珍珠完全是霰石结构,证明小林新二郎的结论是错误的. 相似文献
8.
Sharmishtha Dattagupta Jonathan Martin Shu-min Liao Robert S. Carney & Charles R. Fisher 《Marine Ecology》2007,28(1):193-198
Bathynerita naticoidea (Gastropoda: Neritidae) is a numerically dominant heterotrophic gastropod found at hydrocarbon seep sites on the upper Louisiana slope of the Gulf of Mexico. Snails of this species are commonly associated with beds of the methanotrophic mussel Bathymodiolus childressi (Bivalvia: Mytilidae), and their population structure mirrors that of the mussels they are found among. Previous studies have shown that these snails feed on bacteria and decomposing periostracum on the B. childressi shell. We predicted that B. naticoidea might be attracted to cues specific to its preferred habitat, such as dissolved methane, mucus from conspecific snails, or metabolites produced by B. childressi mussels. To examine this, we used a flow‐through Y‐maze system to investigate the behavior of B. naticoidea exposed to these potential cues. We found that the nerite is not attracted to methane, but is strongly attracted to seawater conditioned with B. childressi. The attractant appears to be specific to this type of mussel, and is not a soluble cue produced by conspecific snails. 相似文献
9.
《Oceanologica Acta》1998,21(5):695-708
This study deals with the colonisation of experimental Porites blocks by epilithic and endolithic algal community in two atoll lagoons and two high-island lagoons in French Polynesia, exposed to different environmental conditions during a 5-year period. A qualitative analysis of the community (cyanobacteria and micro-algae) was carried out, and the relationship between the epilithic and endolithic strata observed. HPLC analysis of chlorophyll pigments was used to quantitatively determine the plant biomass, which was then compared to that of the algal turf of neighbouring reefs. The results show that these blocks are colonised according to two factors: the reef structure (atoll or high-island) and the degree of human disturbance. The epilithic and endolithic population dynamics differ.The density of the epilithic algal community and the species diversity increase with the degree of eutrophication and the amount of borers (sea-urchins, parrotfish), while the proportion of endolithic species remains low (34 %–59 %). This is especially marked in the high-island lagoons, where leaching has caused enhanced nutrient levels. An extreme case is the station at Faaa, a highly polluted harbour, where increased sea-urchin levels (44 ind. m−2) meant that the blocks disappeared completely in less than five years due to bioerosion. In the oligotrophic waters of the atoll lagoons, the losses of CaCO3 by bioerosion do not exceed 35 % per block, and the algal community is made up mainly of endolithic species (66 %–85 %). The algal biomass is lowest in the Takapoto atolls (10–11 μg cm−2) and maximum in Tikehau atoll (23 and 56 μg cm−2). The first microborers to settle in the ecological succession of the community are the cyanobacteria. These are gradually replaced by Ostreobium (Chlorophyceae borers), which become dominant in the blocks exposed to the lowest bioerosion rate. The richness and the density of the algal turf reflect the convergence of many ecological factors: it seems that the covering of epilithic algae or the richness of endolithic flora could be used as a global indicator of the quality and the health of a reef. 相似文献
10.
本文根据1984年3月至1985年2月在厦门港中挂放杉木、松木和柯木试板,研究该港船蛆Teredo navalis数量的时空变化,并讨论了不同污损生物、水温、盐度等对船蛆密度的影响。 相似文献
11.
Abstract. Cladocora caespitosa is a relatively common, colonial, symbiotic, scleractinian coral in the Mediterranean Sea. It inhabits a wide ecological range: hard and soft bottoms, shallow waters or depths to about 50m, calm water or sites exposed to strong currents and wave action. The present study compares the distribution of this coral at two sites, one shallow (3m — wave exposed) and one deeper (12m — soft bottom).
Different parameters including dry weight, volume, and skeletal growth rates were investigated. The polyp biomass, carbon content, and overall area of fully expanded polyps were also measured. Equations are given for the relationship of skeleton diameter to polyp tissue dry weight as well as skeleton diameter to the possible filter area of fully expanded polyps.
C. caespitosa harbors a rich community of vagile and sessile organisms within the skeleton. The cryptofauna was sorted to higher taxonomic levels and their biomass determined. Several highly significant linear relationship were found between skeleton dry weight, volume and cryptofauna biomass. Thus, the determination of colony volume allows the prediction of cryptofauna biomass.
The interstitial space is dominated by sponges - many of them borers - which erode the corallites close to the living tissue until they break off from the colony. At the deeper sampling site, 26% of all colonies are smaller than 2 cm and 48% are smaller than 5 cm. The fragmentation process is discussed with respect to reproduction. 相似文献
Different parameters including dry weight, volume, and skeletal growth rates were investigated. The polyp biomass, carbon content, and overall area of fully expanded polyps were also measured. Equations are given for the relationship of skeleton diameter to polyp tissue dry weight as well as skeleton diameter to the possible filter area of fully expanded polyps.
C. caespitosa harbors a rich community of vagile and sessile organisms within the skeleton. The cryptofauna was sorted to higher taxonomic levels and their biomass determined. Several highly significant linear relationship were found between skeleton dry weight, volume and cryptofauna biomass. Thus, the determination of colony volume allows the prediction of cryptofauna biomass.
The interstitial space is dominated by sponges - many of them borers - which erode the corallites close to the living tissue until they break off from the colony. At the deeper sampling site, 26% of all colonies are smaller than 2 cm and 48% are smaller than 5 cm. The fragmentation process is discussed with respect to reproduction. 相似文献
12.
Water and sediment samples were collected from the Waitemata Harbour, Opua Inlet, and Tutukaka Harbour, and analysed for tributyl tin (TBT) using a hydride generation atomic absorption method. Specimens of oysters (Crassostrea gigas, Saccostrea glomerata, Ostrea heffordi) and oyster borer, Lepsiella scobina, were collected from the Tamaki Estuary and surrounding areas. These specimens were analysed for TBT using graphite furnace atomic absorption, and the oyster shell valves were examined for thickening. Concentrations of TBT in the water column were as high as 0.32 μg TBT‐Sn H. Marina sediments contained up to 0.240 μg TBT‐Sn g‐1. Shell thickening was found to occur in C. gigas where its incidence was correlated with the TBT body burden. Concentrations up to 2.24 μg TBT‐Sn gr‐1 (on a dry weight basis) were observed for C. gigas. This survey provides evidence for the toxic influence of TBT on non‐target organisms in New Zealand. 相似文献
13.
Settlement and colonization of epi‐endobenthic communities on calcareous substrata in an underwater archaeological site 
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下载免费PDF全文 Edoardo Casoli Sandra Ricci Andrea Belluscio Maria Flavia Gravina Giandomenico Ardizzone 《Marine Ecology》2015,36(4):1060-1074
Underwater archaeological sites represent assets of great value that are subjected to physical and biological stresses. The study of biological settlement on calcareous substrata is the first step to understanding the biodeterioration processes that take place on man‐made structures (marble, statues, columns and other architectonic elements) in marine environments. To accomplish this objective, calcareous panels (30 × 30 × 2 cm) were immersed for 3, 6, 9 and 12 months along a north?south transect in marine protected areas of Baia (Naples). Both epilithic and endolithic assemblages were analysed: the latter was observed by scanning electron microscope after the cast‐embedding technique had been used. After 1 year the epilithic community was still changing, with algae and pioneer species overgrown by encrusting organisms, and the endolithic assemblage dominated by cyanobacteria/chlorophyte traces. Changes of epilithics lead changes on endolithics. The initial phototrophic borers were replaced by more sciophilous and competitive species; moreover, the first macroboring organisms arrived after the settlement of grazers. After 12 months of immersion, the rate of bioerosion was high, the material was deeply bored and all of the limestone surface was heavily covered. 相似文献
14.
SAMSUVAN Watchar YEEMIN Thamasak SUTTHACHEEP Makamas PENGSAKUN Sittiporn PUTTHAYAKOOL Juthamart THUMMASAN Monthaphat 《海洋学报(英文版)》2019,38(1):118-127
In this study, we assess coral health by detecting the severity of coral diseases and compromised health states on massive Porites. Field surveys are conducted at twenty-two sites covering the eastern, inner and western Gulf of Thailand as well as the Andaman Sea during 2010-2015. A total of nine coral diseases and signs of compromised health are observed in the waters of Thailand, consisting of pigmentation responses (pink lines, pink patches, pink spots and pink borers), white syndromes (white patches, white bands and ulcerative white spots), growth anomalies, and unusual bleaching patterns. The highest severity of all observed coral diseases and signs of compromised health are found at Ko Khang Khao in the inner Gulf of Thailand, while that observed in the Andaman Sea is relatively low. Composition of the diseases vary across the study sites. Four groups of study sites, in which there is an 80% similarity of diseases or signs of compromised health composition, are clustered and detected based on the Bray-Curtis similarity. The canonical analysis of principal coordinates reveal that most study sites in the Gulf of Thailand, especially the inner Gulf of Thailand, tend to show a high severity of the diseases. The association of disease severity and composition and the level of human impact are also detected. The study sites located near the shores and/or the areas with intensive tourism tend to have higher human impact, especially on poor water quality, which may be linked to the higher severity and composition of coral diseases and signs of compromised health in the Gulf of Thailand. Fish bites are also observed in many study sites. The severity of fish bites in the Gulf of Thailand is much lower compared to the Andaman Sea. Ko Rawi exhibits the highest severity, following by Ko Surin Nua and Ko Butang. The study sites within marine national park boundaries have a significantly higher severity of fish bites than those outside of the marine national park boundaries. This study suggests that higher coral diseases and signs of compromised health severity might be linked to anthropogenic disturbances on coral communities in the waters of Thailand. 相似文献
15.
D. D. Gabaev 《Oceanology》2009,49(2):218-227
The abundance dynamics of several species of bivalve mollusks spats were studied on scallop collectors situated in Minonosok bay of Pos’eta Gulf for 27 years and for 4 years in Kit bay of the Sea of Japan (Russia). A significant positive relation was found between the species having similar thermopathy: the Japanese scallop Mizuhopecten yessoensis and Swift’s scallop Swiftopecten swifti, as well as between the wrinkled rock borer Hiatella arctica and Swift’s scallop Swiftopecten swifti. A significant reverse relation was found between the bay mussel Mytilus trossulus and the Northern Pacific seastar Asterias amurensis. Some of the studied mollusks of Minonosok bay and the remote Kit bay display a significant reversed interrelation in their abundance dynamics caused by the precipitation regime. The one-way dispersion analysis a revealed significant influence of the water temperature in June and the precipitation abundance in the summer on Swift’s scallop’s dynamic abundance. The two-way dispersion analysis showed a significant influence of the ice period duration and the solar activity expressed in Wolf’s numbers on the Japanese scallop abundance dynamics. The uneven years in the period from 1977 to 1984 were usually productive for M. yessoensis and S. swifti spat. After 1985, the even years became more productive (there was asynchronicity in the abundance dynamics compared with 1977–1984). Such asynchronicity appeared with the advent of the new 22-year solar cycle, which caused a change in the magnet polarity in 1986. 相似文献
16.
17.
《African Journal of Marine Science》2013,35(1):139-143
Daily phytoplankton production was estimated at the sea surface in the southern Benguela Current during January, March, April and October 1978 by different methods of calculation. Actual daily production (P24 meas) was obtained from a series of short-term (3—4 h) incubations spanning 24 hours. Daily production was also extrapolated from single measurements during daylight by the "time factor" and "light factor" methods of calculation. These estimates (P24 calc) vary considerably from P24 meas, but on average they underestimate daily production. Estimates by the "light factor" method are generally lower and more variable than those from the "time factor" method. Differences in amplitude and timing of fluctuations in the rate of net production during daylight make it impossible to calculate reliable factors for correcting diel variations in photosynthesis when estimating daily production from short-term measurements. It is suggested that the effects of diel variation in production are likely to be less significant in the euphotic zone as a whole than at the sea surface alone. 相似文献
18.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＯｋｉｎａｗａＴｒｏｕｇｈ (ＯＴ) ,ｌｏｃａｔｅｄｎｏｒｔｈｗｅｓｔｏｆｔｈｅＲｙｕｋｙｕＴｒｅｎｃｈａｎｄｔｈｅＲｙｕｋｙｕｇｕｎｔｏ ,ｅａｓｔｏｆｔｈｅＥａｓｔＣｈｉｎａＳｅａｓｈｅｌｆ,ｉｓａｂａｃｋ ａｒｃｂａｓｉｎｂｕｌｇｅｄｔｏｔｈｅＲｙｕｋｙｕＴｒｅｎｃｈ .ＴｈｅＯＴｅｘｔｅｎｄｓｆｒｏｍＫｙｕｓｈｕｉｎｔｈｅｓｏｕｔｈｗｅｓｔｏｆＪａｐａｎｔｏｔｈｅＩｌａｎＰｌａｉｎｉｎｔｈｅｎｏｒｔｈｅａｓｔｅｒｎＴａｉｗａｎ ,Ｃｈｉｎａｉｎｔｈｅｓｏｕｔｈｗｅｓｔ… 相似文献
19.
作者提出玉米在有节奏生长全过程中的“双S”动态模型。第一个“S”过程是从出苗到开花授粉阶段,这一过程主要是根、茎、叶以及花器的建成。第二个“S”过程是从开花授粉到籽粒成熟阶段,这一过程光合产物的积累主要用于籽粒的增重。作者认为:“双S”生长模型揭示了玉米生长的内在规律,有助于玉米栽培管理科学化。 相似文献
20.
Jean-Christophe Sempere Alexandra Meshkov Michel Thommeret Ken Macdonald 《Marine Geophysical Researches》1988,9(2):131-146
We report the results of a study of the magnetic properties of basalts recovered from the axis and from 0.7 m.y. old crust at 21° N and 19°30 S on the East Pacific Rise as well as from the 9°03 N overlapping spreading centers. The natural remanent magnetization of the samples from 21° N and 19°30 S decreases from the axis to 0.7 m.y. old crust as a result of low-temperature oxidation. In addition, the magnetic properties of the samples from the 21° N sites indicate that: (1) the magnetic susceptibility and the Koenigsberger ratio decrease with low-temperature alteration, (2) the Curie temperature, the median demagnetizing field and the remanent coercivity increase with maghemitization, (3) the saturation magnetization measured at room temperature does not change significantly with age. The magnetic properties of the basalt samples from the 9°03 N overlapping spreading centers indicate the presence of a high magnetization zone at the tip of the eastern spreading center. This high magnetization zone is the result of the high percentage of unaltered, fine-grained titanomagnetites present in the samples. These measurements are consistent with the results of the three-dimensional inversion of the magnetic field over the 9°03 N overlapping system [Sempere et al., 1984] as well as with detailed tectonic and geochemical investigations of overlapping spreading centers (Sempere and Macdonald, 1986a; Langmuir et al., 1986; Natland et al., 1986). The high magnetization zone appears to be the result of the eruption of highly fractionated basalts enriched in iron associated with the propagation of one of the limbs of the overlapping system into older lithosphere and not just to rapid decay, due to low-temperature oxidation, of the initially high magnetization of pillows extruded in the neovolcanic zone. 相似文献