新疆北塔山晚志留—早泥盆世苔藓虫

本文描述的上志留统一下泥盆统的苔藓虫标本产自新疆东准噶尔北塔山地区。上志留统考克赛组中包括6属7种,它们是:Fistulipora granulosa Astrova, Hallopora xinjiangensis Lu, Semicoscinium pyramidatum Kopaevich, Sem. fragilis Astrova, Chasmatopora sp., Orthopora sp., Sceptropora sp.; 下泥盆统托让格库都克组中包括2属3种:Fistulipora Sp., Semicoscinium baytikensis Wang et Lu(sp. nov.), Sem. kurjensis Nekhoroshev.根据上述苔藓虫组合特征,可建立两个苔藓虫组合,上志留统为Fistulipora granulosa-Hallopora xinjiangensis组合;下泥盆统为Semicoscinium baytikensis-Sem. kurjensis组合。     

Hydrolytic enzymes of the paua Haliotis iris,a marine gastropod (note).

Extracts of the viscera of Haliotis iris (Martyn, 1784) were shown to hydrolyse 2‐hydroxy‐5‐nitrophenyl sulphate at pH 5.5, and the p‐nitrophenyl derivatives of α‐ and β‐D‐galactose, α‐ and β‐D‐mannose, α‐L‐lucose, β‐D‐glucuronic acid, β‐N‐acetyl glucosamine and phosphate at pH 4.0 and 5.5: p‐nitrophenyl‐β‐L‐fucose was not hydrolysed.     

Within‐colony variation in skeletal mineralogy of Adeonellopsis sp. (Cheilostomata: Bryozoa) from New Zealand

Three colonies of the erect, robust branching, cheilostome bryozoan Adeonellopsis sp. were collected from Doubtful Sound, New Zealand, to investigate within‐colony variation in carbonate mineralogy. One‐hundred‐and‐twenty‐one sections from 9 branches were found to contain mostly aragonite, with calcite ranging from 1.1 to 7.3 wt% (mean ± SD = 2.4 ± 1.2 wt%, n = 120). The magnesium (Mg) content in calcite ranged from 5.3 to 13.1 wt% magnesium carbonate (8.8 ± 1.0 wt% MgCO₃; n = 120). Calcite content decreased with increasing age proximally along the branch, indicating that secondary thickening is achieved with aragonite. In contrast, an oscillating trend in Mg content along branches suggests that seasonal or interannual environmental parameters may influence this geochemical parameter. Mineralogical variability highlights the need for multiple samples from the same colony to be measured when determining quantitative carbonate mineralogy in bryozoans. Bimineralic bryozoans such as Adeonellopsis sp. may have lower preservation potential than monomineralic bryozoans, and consequently may not survive diagenesis to become fossils. Bimineralic species may also be more vulnerable to dissolution pressure and possible ocean acidification than monomineralic calcitic taxa.     

Colonisers of the dark: biostalactite‐associated metazoans from “lu Lampiùne” submarine cave (Apulia,Mediterranean Sea)

Metazoan/microbial bioconstructions, or biostalactites (BSTs), discovered in submarine caves of Apulia c. 20 years ago—and later found in several shallow‐water Mediterranean caves—are receiving increasing attention in the last years. Examination of a single BST from the “lu Lampiùne” cave (Apulia), at the limit between the Adriatic and the Ionian seas, has been addressed for the first time in this paper. The BST started growing at c. 6,000 years ago with a rapid accretion of large‐sized serpulids (Protula), slowing down since about 3,000–4,000 years ago with a shift in main bioconstructors, probably caused by environmental changes. The present‐day community on the outer BST surface is dominated by skeletonised epibionts, mostly small‐sized serpulids, bryozoans and foraminifers, which contribute carbonate to the BST growth, by encrusting sponges, and by a few endobionts, including boring bivalves and insinuating sponges. New data remarkably increase biodiversity known for the “lu Lampiùne” cave and the cave habitat in the region. Thirty‐five taxa (16 bryozoans, 10 serpulids, 3 brachiopods, 2 foraminifers, 2 sponges, 1 bivalve and 1 cirriped) are recorded for the first time from Apulian marine caves, highlighting the need for further research in the area. In addition, the BST‐associated community seems to differ from those of individual BSTs from other Mediterranean caves, revealing the individuality of these communities.     

Fourier packing ordinate: A univariate size-independent measurement of the polygonal packing variation in Paleozoic bryozoans

The Fourier packing ordinate provides a highly sensitive, univariate, and size-independent measurement of the polygonal packing variation in Paleozoic bryozoan colonies. It is potentially useful in quantifying a wide variety of natural packing arrays or polygonal networks, and is preferable to counting the sides of polygons, the frequency of triple or quadruple junctions, the nearest-neighbor statistic, measurements of surface area per unit cell, or individual harmonic amplitudes. Fourier shape analysis provides exact measurements of the levels of two- to six-fold rotational symmetry in all natural packing gradients. In bryozoans these symmetries are intercorrelated because as each order of symmetry is increasing, the previous order is decreasing. Shapes in these packing arrays are normally hybrids of two or more orders of rotational symmetry. The levels of rotational symmetry involved in these packing gradients are significantly correlated with a single principal component, the Fourier packing ordinate, which is independent of both size and cell boundary phenomena. Spatial analysis of the Fourier packing ordinate within an Ordovician bryozoan colony reveals both variation in packing caused by subcolony budding, as well as large scale trends which vary from the colony center to the free-growing margin.     

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.     

The effect of encrusting bryozoans on the photosynthetic activity of Fucus serratus L.

A photosynthetic gradient along the fronds of the serrated wrack, Fucus serratus L. is described. Within the epifaunal communities associated with the fronds of F. serratus certain species are known to settle preferentially in the distal, less heavily encrusted, regions of the plant; thus a gradient in photosynthetic activity could provide an important mechanism by which the prospecting larvae of such species are able to discriminate between different regions along individual fronds. Photosynthesis is significantly depressed in F. serratus fronds which are heavily fouled by the fleshy encrusting bryozoans, Alcyonidium hirsutum (Fleming) and Flustrellidra hispida (Fabricius). Electra pilosa (L.), a calcareous opportunistic bryozoan, has a less marked effect on photosynthetic activity. The selective costs of dense epifaunal assemblages on their algal hosts are briefly discussed.     

Seasonality of Competition in Early Development of Subtidal Encrusting Communities

Abstract. Settlement panels immersed at Lough Hyne, County Cork, Ireland, at six stations with widely different flow regimes were retrieved at monthly intervals. Between 40 and 62 taxa were identified at each station during the study period. Percentage cover, number of interactions and number of recruits were recorded. Space occupied was found to vary more than 2.5 orders of magnitude between stations and seasons (0.3 – 82 %). Competition for space was most intense during summer, when recruitment was highest. More than 3600 interactions between pairs of species were recorded and competitive matrices are presented for the two stations with the most interactions. Both number of interactions and % cover were significantly higher at sites with greater water flow. The nature and the degree of competition varied between sites, with the most intense competition occurring in the very high flow sites with a large proportion of intra­specific encounters. Colonial species were more evident at the sites with high flow. Certain solitary species (notably Anomia ephippium and Pomatoceros spp.) were successful competitors in encounters with cheilostomatid bryozoans. Solitary species may prevent space monopolisation by the faster-growing bryozoans. 'Typical' early successional species, notably bryozoans such as Celleporella hyalina and Microporella ciliata, were more abundant at the more disturbed sites, implying either a larger adult population and/or preferential settlement of these species at such sites.     

Post‐glacial biota from the inner part of southwest Joseph Bonaparte Gulf

Seventeen vibrocores from the inner part of Joseph Bonaparte Gulf off northwestern Australia penetrate a range of marine and marginal‐marine sediments deposited in the post‐glacial transgression and highstand. Ranging from gravelly sand to fine silt, these sediments contain a diverse fossil biota dominated by molluscs and bryozoans, but also including ostracods and foraminifers. Minor components include solitary corals, echinoids, soft coral and sponge spicules, wood debris and bone fragments. The biota can be divided into five major marine or marginal‐marine environments (intertidal, lagoonal, estuarine, strandline and shelf) and one terrestrial (riverine) environment. The intertidal environment contains four sub‐assemblages (mangroves, salt marsh, mud flat and sand flat) and the shelf environment six sub‐assemblages (hard substrate inner shelf, sandy substrate inner shelf, muddy substrate inner shelf, epiphytic, inshore and oceanic). The most useful organisms for palaeoenvironmental reconstruction are bryozoans for differentiating various shallow‐marine substrates, and foraminifers and ostracods for defining water depths, euryhaline, freshwater and oceanic influences. Palynomorphs were the only microfossils capable of providing control on terrestrial environments. The scarcity of marine plankton and the dominance of terrestrial palynomorphs in these marine sediments provides a salutary warning of the dangers of relying on plant microfossils alone when no independent environmental data are available to test the interpretation. The mollusc and bryozoan biota in the inner part of Joseph Bonaparte Gulf superficially resembles the bryomol assemblage of cool‐water shelves. This biotic assemblage is the result of turbidity rather than water temperature. The turbidity suppresses the photosynthetic, zooxanthellate and hermatypic organisms allowing molluscs, bryozoans and other apparently cool‐water biotic elements to dominate.