Cementation in cold-water bryozoan sand, Tasmania, Australia

Cold-water (<3–11°C) carbonate is the predominant sediment on the Tasmanian shelf. Calcitic skeletal grains (bryozoa, foraminifera, echinoderms, etc.) predominate over aragonitic (gastropods, etc.) ones. Non-skeletal grains are mostly micritic intraclasts with some pellets.

Fibrous spherulitic and rhombohedral calcite submarine cements range up to 90% in the bryozoan sand. X-ray analyses show that the bryozoan sand is characterized by a spectrum of calcites (low to high magnesian) and some aragonite.

A uniform spread of Mg concentrations from 0.06 to 2.48 wt.% indicates <3–10°C ambient water temperatures. The Mn (10–360 ppm) and Fe (176–2499 ppm) concentrations increase with increasing Mg values due to the formation of impure CaCO₃ phases. The Sr content in bryozoan sand (bryozoa = 3200 ppm Sr) decreases with increasing rhombohedral calcite cement, as low Mg-calcite precipitating from 3° C sea water would have 1350 ppm Sr. The bryozoan sand grains with fibrous spherulitic calcite cements have high Sr concentrations (4470–7000 ppm), in the same range as in aragonitic (detected only by X-ray analyses) bryozoan sand grains. The spherulitic calcite cements are either pseudomorphs after original aragonite cements or these calcite cements and aragonite were inverted from fibrous spherulitic vaterite, a predominant CaCO₃ polymorph at temperatures <10°C.     

Waulsortian-like mounds of the Mississippian Pekisko Formation, Northwestern Alberta: Petrographic and chemical attributes

The Tournasian age Pekisko carbonates in the Normandville Field (northwestern Alberta) form waulsortian-like, bryozoan/crinoid mounds that developed in fairly deep, low energy, cool water systems, close to the ramp margin. Three main depositional environments occur: (1) crinoidal apron with wackestone, grainstone and floatstone facies; (2) mound flank with grainstone, wackestone, packstone and floatstone facies dipping 35°; and (3) bryozoan mound core, composed of rudstone and floatstone facies with fenestrate bryozoa, minor crinoids and carbonate mud. Local highs due to fault-bounded blocks, created from the collapse of the Devonian Peace River High, may have controlled the location of mound nucleation.Diagenesis of the bryozoan/crinoid mounds included calcite cementation, compaction, dolomitization, silicification, and hydrocarbon emplacement events. The mound core facies contains submarine fascicular optic calcite and bladed/prismatic calcite cements, and later ferroan, brightly luminescent, pore-filling blocky spar cement. The crinoid apron facies contains syntaxial cement associated with crinoids, and the ferroan blocky spar cement. The mounds are dominantly limestone; however, in one well, dolomite dominates the lower section. Four types of dolomite have been identified: partial replacive; chemical-compaction-related, pervasive dolomite and saddle dolomite cement. All dolomites are non-stoichiometric (CaCO₃ mole% 56.6–62.6). The partial, zoned replacive dolomite replaces micrite and syntaxial rim calcite in mound flank and crinoid apron facies. The chemical compaction-related dolomite is found along dissolution seams and stylolites and has similar CL characteristics to the replacive dolomite. The pervasive dolomite is fabric destructive and has dull cores and bright rims in CL. Saddle dolomite (0.15 mm) has brightly-luminescent, concentric zoning and occurs in vugs and fossil pore spaces.Chemical and isotopic analysis of the bryozoan/crinoid mounds indicate that the original marine signatures in micrite, early cements, some crinoids and brachiopods have been preserved. However, carbon isotopic values for some crinoids, matrix and dolomite show more positive values compared to known Mississippian carbonate values. Recrystallization during shallow burial has reset the oxygen isotopic composition of some crinoids and micrite. Oxygen and carbon isotopic compositions of most dolomites overlap with altered crinoids and early calcite cements. However, saddle dolomites have lighter δ¹⁸O values, similar to saddle dolomites from the Devonian Wabamun Group in this area. The isotopic variations in later ferroan calcite cements show an inverted-J trend, possibly due to variable amounts of water-rock interaction. While the Sr-isotopic ratio of submarine calcite cement coincides with that of Mississippian seawater, the later ferroan calcite cement is more radiogenic, indicating a different source of fluids.     

The Bryozoan Rhynchozoon larreyi (Audouin, 1826)–A Successful Competitor in Coral Reef Communities of the Red Sea

Abstract. Rhynchozoon larreyi (A udouin , 1826) is a successful competitor for space in sessile reef communities at Port Sudan and Eilat (Red Sea). At these localities it has always been found in association with Zanclea sp. The relationship between the two species is regarded as mutualistic. The hydroid benefits through association with a successful spatial competitor; the bryozoan gains advantage through protection of its surface from predation and fouling. Morphological modification of the bryozoan colony in response to this association leads to a highly organized reticulate surface pattern, which provides both symbionts with access to feeding currents.     

The rate of feeding of the bryozoan,Zoobotryon verticillatum

The ctenostome bryozoan Zoobotryon verticillatum was found to clear suspensions of four species of algae, at rates ranging from 0.152–1.05 ml per zooid per hour, or 13.9–96.2 ml per mg dry weight per hour, when the algal suspensions were below the satiation concentrations and thus maximum clearance rates would be expected. Suspensions of Monochrysis lutheri, a small flagellate on which the bryozoan grew well and with which most experiments were made, was cleared below the satiation concentration of 7,900 cells per ml, at the mean rate of 0.368 ml per zooid per hour or 33.7 ml per mg dry weight per hour.

Satiation concentrations of the four species of algae were of the same order as the highest concentrations of nannoplankton to be expected in the bryozoan's natural habitat.

The bryozoan colony fed fairly constantly over a 48 hour period.

Assuming oxygen consumption was similar to that of other bryozoans, Zoobotryon verticillatum cleared about 11.6 litres per ml of oxygen consumed.     

Interactions Between Small Sciaphilous Scleractinians and Epizoans in the Northern Mediterranean, With Particular Reference to Bryozoans

Abstract. Two small sclcractinians, Lepfopsummiu pruvoti (solitary) and Hoplungiu dur-olrix (colonial, aggrcgatcd or not), which arc common pcrcnnial componcnts of Mcditcrrancan submarinc cavcs and dccp vcrtical walls, bcar many cpibionts on thc lowcr part of thcir corallitcs. Samplcs were collectcd ncar Marscillcs (7–58 in) undcr various cnvironmcntal conditions and coral densitics. Frequency of occurrencc of thc major cpizoan groups and of individual bryozoan spccics overgrowing the corallites varies according to habitat charactcristics and to acccssibility of the individual corallitcs for adjaccnt epizoans. Thc most frcqucnt colonizcrs arc: bryozoans (by vcgctative growth and larval settlcrnent), sponges (mainly by vcgctativc growth), and scrpulids. Among the 40 recorded bryozoan species (26 on Leptopsammia, 28 on Hoplangiu), 15 spccics are relatively frequent on each host. Comparisons of data from the corallites with thosc obtained from adjoining samples indicatc the preference for coral substratc of Pucflina radiata. This encrusting bryozoan is highly predominant on both Leptopsammia and Hoplangiu as well as on other scleractinian species. SEM observations show that overgrowth processcs are reversible and that corals may control the invading encruSters by embedding them in their sclerenchyme. The balance and benefits of this epizoan/host system are discussed.     

Studies on Antineoplastic Constituents from Marine Bryozoan Bugula neritina Inhabiting South China Sea (Ⅲ): Isolation and Structural Elucidation of Bryostatins 10, 11 and 18

Six active compounds are isolated from the marine bryozoan Bugula neritina,inhabiting the Nanwan Bay in the South China Sea, using the bioassay-guided method with a combination of extraction and partitionation with suitable solvents as well as multiple column chromatographies ( Sephadex LH-20, ODS and preparative HPLC).Their structures are identified as known bryostatins-bryostatins 4, 5, 6, 10, 11 and 18 through intensive analysis of the data of high resolution 2D NMR (600 MHz, DQF-COSY,TOCSY, HMQC and ROESY) and ESI-MS. Among them, bryostatins 10, 11 and 18 are for the first time obtained from this bryozoan in the South China Sea and they show significant antineoplastic activities in vitro.     

东海大陆架掌苔虫属一新种

掌苔虫属(Genus Kinetoskias Danielsen,1868)隶于唇口目、无囊亚目、双胞科(Cheilostomata, Anasca, Bicellariellidae),除南极海域、地中海、加勒比海未见报道外,各地都有记录,但多数种类在北极海域分布较广(Kluge,1953)。掌苔虫系深海类型,有的种能栖息在水深4670米的深海海底。掌苔虫的个虫系草苔虫型(Bugula-type),与草苔虫不同处是个虫始端不分叉。掌苔虫和茎苔虫(Caulibugula Verrill,1900)的群体都由一根长柄和分枝部分构成,但掌苔虫的长柄为膜质;无任何钙质沉淀,仅由一空个虫(keno zooid)构成,而茎苔虫的长柄分节,由许多空个虫构成,往往有钙质加厚,因而两属极易区分。掌苔虫群体分枝的分歧方式属于Harmer的模式7(见Harmer，1923:326,pl,16,fig.7)，即双列分枝在分歧时,两个内个虫(inner zooids)F和G分别由轴个虫(axillary zooid)E相连接,轴个虫产个虫F和G,它伸到与个虫A对应一侧分枝的始端,个虫B不参与个虫数目的复分(图2)。 掌苔虫虽系深海类型,但有的种深度分布范围很广,如Kinetoskias arborescens栖息在水深19-1229米,K.smitti分布在水深65-1210米,S. mitsukurii则分布在水深20-3400米(Kuge1953、1962；Menzies1963)。 掌苔虫的群体借助于膜质长柄插入海底淤泥,由长柄始端分出的微细附根附着在砂粒等基质上。个虫由于特殊的个虫牵引肌(flexor: Zooidal muscles)的伸縮彼此间能活动。鸟头体皆侧位,都长在个虫自由缘上,或位于个虫中点(mid-point)。或位于中点以上(cephlad of the mid-point),或位于中点以下(caudad to the mid-point);有的种鸟头体长在特殊阶梯状突起(step-like process)上,但有些种类无此阶梯状突起。     

Algae as hosts for epifaunal bryozoans: Role of functional groups and taxonomic relatedness

Macroalgae build biogenic habitats which give shelter and provide a suitable physical environment for a great variety of organisms. Structural complexity of algal substrates may influence the composition of their attached epifauna. The aim of this study is to test whether the taxonomic relatedness of the algal hosts and the functional groups to which they belong influence the species richness and composition of their epifaunal bryozoans. We analysed 36 algal genera from the Atlantic coast of South America between 42°S and Cape Horn. Changes in bryozoan species richness (number of species) among different algal functional groups (filamentous algae, foliose algae, corticated foliose algae, corticated macrophytes) were non-significant. The composition of the epifaunal assemblages differed significantly only between filamentous and foliose algae. Sheet-like bryozoans (i.e. encrusting, pluriserial colonies) were more frequent on foliose than on filamentous algae, while runner-like species (i.e. uniserial stolons) were characteristic epibionts on filamentous thallii. Similarity of bryozoan assemblages increased with increasing taxonomic relatedness of their hosts. As most filamentous seaweeds analysed in this study are members of the Order Ceramiales, the influence of algal taxonomic relatedness and functional groups on the composition of their bryozoan assemblages can be viewed as two different aspects of the same phenomenon.     

Al基牺牲阳极的生物污损——“阳极苞”的解析

本文介绍了铝(Al)基牺牲阳极在青岛中港海鸥浮码头超期服役五年半的阴极保护情况。现场勘查结果发现少部分Al阳极是以"苞"状出现,暂命名为"阳极苞"。其外层为以苔藓虫(Bryozoa/Polyzoa)为主体的生物群落构成的具有一定强度的生物硬壳,内层为白色膏状物,暂命名为"阳极泥"。对生物硬壳进行了生物鉴定,利用扫描电镜(scanning electron microscope,SEM)测试其微观结构,红外光谱(infrared spectroscopy,IR)测定其化学组成,结果表明该生物硬壳由复杂的有机混合物组成,并且具有微米级多孔结构;对"阳极泥"进行了酸碱性测定、能谱分析(energy dispersive spectrometer, EDS)及X射线衍射(X-ray diffraction, XRD)分析,结果表明"阳极泥"主要由铝的水合氧化物和污损生物的代谢产物及机体分解产物组成。在此基础上初步讨论了"阳极苞"的形成过程及其对阴极保护的影响。     

Diversity and Distribution of the Bryozoa along Underwater Cliffs in the Adriatic Sea with Special Reference to Thermal Regime

Abstract.  The diversity and distribution of bryozoans have been surveyed at two localities, Cape Struga on Lastovo Island (South Adriatic) and Cape Šilo on Prvić Island near Senj (North Adriatic), with similar characteristics of topography and exposure but markedly different sea temperature conditions. Continuous measurements over one year have shown that temperature conditions differ in two aspects. First, the annual range of temperature is much larger in the North. Second, in the South during summer, marine life within the thermocline layer is exposed to large high-frequency temperature oscillations, partly due to an internal diurnal tide, a phenomenon recorded for the first time in the Adriatic. Altogether, 78 species have been recorded, 57 in Lastovo and 50 in Prvić, and 29 in both localities. The comparison of mean zooid lengths of 14 bryozoan species occurring at both localities indicates no consistent difference in zooid size between northern and southern sites. Seventeen bryozoan species have been recorded in the Eastern Adriatic Sea for the first time.     

Polymorphic Zooids in Deitaic Species Populations of Conopeum seurati (CANU, 1928) (Bryozoa, Cheilostomata)

Abstract. Deltaic populations of Conopeum seurati from diverse environmental settings have variable phenotypes related to strong competitive regimes and to dissolved oxygen minima. Under extremely stressful conditions, the poorly canalized phenotype of C. seurati displays new additional features such as kleistozooids ( kleistós = closed) and chaotic celleporoid layers. Kleistozooids are clearly distinguishable polymorphs characterized by the presence of a compact, imperforate frontal membrane and by a strongly reduced lumen of the "opesium". They commonly aggregate in clusters of regularly-arranged individuals that store a large quantity of proteic material. The inferred function of these cell-like structures is to supply nutrients for basic colony activities. Celleporoid layers are, possibly, a developmental relaxation of the colony of C. seurati for a more efficient use of space in competitive interactions.
Both celleporoid layers and kleistozooids reveal the magnitude of intracolony variability of a widespread opportunistic bryozoan species.     

Regional and temporal changes in epizoobiontic bryozoan-communities of Flustra foliacea (Linnaeus, 1758) and implications for North Sea ecology

Until recently, bryozoans have not been used as indicators for changes in bottom communities or climate control in the North Sea Basin, despite a 200-year history of bryozoan collecting. The epizoobiontic bryozoan fauna of Flustra foliacea (Linnaeus, 1758) was analysed on 51 sample stations kept in four German museums. The samples cover the entire North Sea and different time periods (1776–2008, mainly the period of 1904/1905 compared to 1980–87). Cluster analysis shows a differentiation into a northern and a southern North Sea assemblage. The northern assemblage is characterized by Amphiblestrum flemingii (Busk, 1854), Callopora dumerilii (Audouin, 1826) and Tricellaria ternata (Ellis & Solander, 1786), while the southern North Sea is characterized by Electra pilosa (Linnaeus, 1767), Crisia eburnea (Linnaeus, 1758) and Plagioecia patina (Lamarck, 1816). Spatial separation approximately follows the 50 m depth contour. The temporal distribution patterns of bryozoans are discussed in terms of NAO (North Atlantic Oscillation) and temperature variations.     

Zooidal budding in the cheilostomatous bryozoan Fenestrulina malusii var. thyreophora

Zooidal budding in Fenestrulina malusii var. thyreophora is described and notes on the budding of Micropora mortenscni are included for comparison. In both, an autozooidal bud arises from a membranous window in the exterior wall of a dietella. Dietellae themselves arise by being delimited as dichotomies of the developing lateral walls of autozooids. Because of the structural discreteness of dietellae of Fenestrulina and Micropora, and Hastings’ (1963) observation that some dietellae of Microporella occur as avicularia, dietellae in the Microporellidae and Micropora are regarded as fully formed heterozooids and not merely as incipient zooid buds, as lateral septulae are. The formation of dietellae in Fenestrulina and Micropora is a continuous process, and comparable with the con‐strictive budding of distal autozooids of Membranipora and Metrarabdotos.     

Stable isotope composition of modern bryozoan skeletal carbonate from the Otago Shelf,New Zealand

The oxygen (δ¹⁸O) and carbon (δ¹³C) isotope ratios of 10 species of living Bryozoa collected from the Otago Shelf, New Zealand were analysed to assess the extent to which isotopic equilibrium (relative to inorganic equilibrium isotope fractionation) is attained during the precipitation of skeletal calcium carbonate. The data reveal that whereas eight species of Bryozoa synthesise skeletal carbonate in apparent oxygen isotope equilibrium with respect to environmental conditions, two species (Celleporina grandis and Hippomonavella flexuosa) yield δ¹⁸O_calcite values which indicate significant disequilibrium oxygen isotope fractionation during calcification. Sufficient data are available from one species (C. grandis) to demonstrate that disequilibrium is probably related to kinetic factors associated with diffusion‐controlled transport of HCO₃‐ to the site of calcite precipitation. Carbon isotope signatures indicate significant departures from inorganic isotope equilibrium in all but one bryozoan species (Hippomenella vellicata). Although greater uncertainties are associated with estimates of the isotopic composition of total dissolved inorganic carbon (δ¹³C_SDIC), the data suggest that two factors—kinetic fractionation and incorporation of respiratory CO₂—are important in controlling carbon isotope disequilibrium. Where bryozoan species exhibit evidence for disequilibrium in both oxygen and carbon isotope systems (C. grandis, H. flexuosa), it is likely that kinetic factors are primarily responsible for observed departures from carbon isotope equilibrium. In contrast, the probable explanation for those species which display evidence for carbon isotope disequilibrium only, is that skeletal carbonate is precipitated from a DIC pool modified by the incorporation of respiratory CO₂. Differences between the carbon isotope composition of skeletal elements from the same species and co‐existing species living in the same community suggests that significant variations may occur in the extent to which marine DIC and respiratory CO₂ are utilised during calcification. Additional studies of carbon pathways associated with calcification are required to assess the relative effects of kinetic, metabolic, and environmental factors on the carbon isotopic composition of bryozoan skeletal carbonate.     

Marine biofouling in Hong Kong:a review

From 1980 to 1998, biofouling communities in Hong Kong waters, the Zhujiang RiverEstuary and the Mirs Bay were studied and a total of 610 samples. The samples were collected from ves-sels, buoys, piers and cages. Totally, 340 species (see Appendix Ⅰ ) have been recorded and identified,six of which are new. At the same time, research on the biology of the cirripede, bryozoan, polychaeteand mollusc communities were also conducted. Twenty-three related papers have been published. Thisreview summarizes works in Hong Kong over past twenty years, and some unpublished data are also re-ported.     

Notes Marine biofouling in Hong Kong: a review

From 1980 to 1998, biofouling communities in Hong Kong waters, the Zhujiang RiverEstuary and the Mirs Bay were studied and a total of 610 samples. The samples were collected from vessels, buoys, piers and cages. Totally, 340 species (see Appendix I ) have been recorded and identified, six of which are new. At the same time, research on the biology of the cirripede, bryozoan, polychaete and mollusc communities were also conducted. Twenty-three related papers have been published. This review summarizes works in Hong Kong over past twenty years, and some unpublished data are also reported.     

Effects of temporal dynamics and vertical structure of the seagrass Zostera caulescens on distribution and recruitment of the epifaunal encrusting bryozoa Microporella trigonellata

Seagrass is an ephemeral habitat for epifaunal sessile invertebrates attaching on seagrass leaves, and spatial and temporal dynamics of seagrasses strongly affect the distribution of epifauna. Zostera caulescens Miki, a seagrass species endemic to Japan, provides a complex habitat for epifauna with two types of shoots: vegetative, less than 1 m tall, and flowering, 5–7 m tall. We conducted monthly field observations and a manipulative field experiment to investigate the effects of the seagrass vertical structure and its temporal variation on the distribution and recruitment of the encrusting bryozoan Microporella trigonellata. The density of M. trigonellata on the leaves of flowering shoots, located at the seagrass canopy, varied temporally, reaching maximum in summer and minimum in winter. In contrast, M. trigonellata density on the leaves of vegetative shoots near the sea floor was consistently low throughout the study period. Early recruit bryozoans also showed this temporal and vertical variation in density; thus spatial and temporal variation in recruitment determined the distribution of the whole colonies. The field experiment revealed that the recruitment rate of M. trigonellata was significantly higher at the higher position of the water column (3 m above the sea floor) than at the lower position (0.5 m) in June. However, the recruitment rate was higher at the lower position in October when most of the flowering shoots started falling down. The temporal change in bryozoan habitat selection is considered to be adaptive to maintain their population on the seagrass leaves that show complex temporal dynamics.     

一种适于内陆水域生态实验用的浮式围隔

本围隔由浮体,围隔袋,底盘,内网和搅水机等５部分组成。围隔袋呈圆筒形,由聚乙烯纺织布缝合而成,高５．７ｍ,容水量１４．３ｍ＾３。底盘水是围隔的底部。内网与围隔袋相套合,供检查鱼和捕鱼之用。搅水机的动力是９０Ｗ的电动机,其作用是定时搅水,以保持围隔内水的混合与围隔外大小体基本一致。灌水采用“沉下提上法”,每灌一个围隔只需１０余分种。使用结果证明,本围隔性能良好,操作简便而又牢固安全。     

海洋初级生产力的结构

海洋初级生产力的研究发展到今天,其内涵和信息已不是一个简单的量值所能表达得了的,必须建立起一个能够反映其生态学意义的关于生产力结构的概念。在这个概念中,初级生产力的结构归纳为以下4个方面:(1)组分结构,即不同类群生产者(包括自养微生物、各类浮游植物等)对初级生产力贡献的比例;(2)粒级结构,即不同粒径级(<2μm,2—20μm,>20μm)生产者对初级生产力贡献的比例;(3)产品结构,即初级生产产品中颗粒有机碳(POC)和溶解有机碳(DOC)的分配比例;(4)功能结构,即新生产力占总初级生产力的比例。