Coralline red algal limestones of the late Eocene alpine Foreland Basin in Upper Austria: Component analysis, facies and palecology

Summary Late Eocene sediments of the Upper Austrian Alpine Foreland Basin discordantly overlie Mesozoic and crystalline rocks, which are deeply eroded and form a distinct pre-Eocene relief. Late Eocene deposits contain red algal limestones with a remarkable lateral extent and a high diversity of sedimentary facies. Towards the south the algal limestones change into more clastic sediments, which are characterized by larger foraminifera and bryozoans. Main components are coralline algal branches and detritus, coralline crusts, rhodoliths, peyssonneliacean aggregates and crusts, nummulitid and orthophragminid foraminifera, corals, bryozoans, as well as terrigenous components. Rank correlation and factor analysis were calculated in order to obtain informations about relations between components. Hierarchical cluster analysis allowed the designation of 17 facies, most of them are dominated by coralline algae. Actualistic comparisons and correlations obtained from statistical analyses allowed the reconstruction of the depositional environments. Main features of the northern area are huge accumulations of unattached coralline algae (branches, rhodoliths, detritus), which are comparable to the present-day “Maerl”-facies. They formed loose frameworks cut by sand channels. The frequency of coralline detritus decreases upsection. Peyssonneliacean algae in higher parts of the profiles show growth-forms that are comparable to peyssonneliaceans of the Mediterranean circalittoral soft bottoms. This succession can be interpreted by an increasing relative sea level. Besides, crustose coralline algal frameworks were growing on morphological highs which are partially comparable to the present-day “Coralligéne de Plateau” of the Mediterranean Sea. In contrast to the northern area, sedimentation rate of the southern area is too low to keep up with rising sea level. The typical succession from nummulitid- to orthophragminid-and bryozoan-dominated facies can be interpreted by an increasing water depth from shallowest subtidal to the deeper photic zone and finally to the aphotic zone.     

Coralline algal facies and their palaeoenvironments in the Late Eocene of Northern Italy (Calcare di Nago, Trento)

Summary The Calcare di Nago is a carbonate unit of Middle-Late Eocene (Bartonian and Priabonian) age which is well exposed at the north-eastern end of Lake Garda, on the western margin of the Lessini Shelf (Southern Alps). This unit is highly fossiliferous as far as the coralline red algae and large foraminifera are concerned. Corals, bryozoans, echinoderms, and molluscs are also present. The present study deals with the relationships among the coralline taxa, the coralline growth-forms, and their facies development in the Priabonian part of the type section of the Calcare di Nago. The taxonomic investigation led to the identification of 15 coralline red algal species belonging to 7 non-geniculate and 2 geniculate genera. One species of Peyssonneliacean (red alga) and one of Halimedacean (green alga) were also recognized. The quantitative and qualitative analyses based on coralline red algae and large foraminifera enabled five facies to be distinguished: Algal crust-branch rudstone, Algal/Discocyclina packstone, Coralalgal boundstone, Rhodolith mound wacke/packstone, and Rhodolith pavement. According to the coralline assemblages, coralline growth-forms, and large foraminiferal associations, the five facies reflect solid and soft substrate types. Some of these facies are dominated byin situ rhodoliths, others by reworked algal debris. In the architecture of an interpreted prograding carbonate ramp, shallow water facies are dominated by members of the subfamily Mastophoroideae, while deeper water facies are dominated by those of the subfamily Melobesioideae and family Sporolithaceae. There is a significant increase both in size and in constructional voids of the rhodoliths with depth. A concomitant decrease in algal species diversity with depth has been also recognized. LargeDiscocyclina assemblages are localized across the inner and mid ramp boundary.Pellatispira andBiplanispira are present only in the uppermost mid-ramp.Nummulites, Assilina, andSpiroclypeus are dominant together with small orthophragminids both in the mid- and uppermost outer ramp facies.     

Coralline algal maerl frameworks-Islands within the phaeophytic kelp belt

Summary In the subtropical belt highly productive ecosystems are formed by coral reefs in oligotrophic seas. Towards more eutrophic conditions, coral reefs diminish and are subsequently replaced by highly productive kelp forests. In high latitudes framework constructing carbonate production is enhanced by the growth of branching coralline algae which predominantly generate maerl-type deposits. On a global view, these coralline algal ecosystems show an island-like distribution pattern within the phaeophytic kelp belt. Compared to kelp ecosystems, coralline-algaldominated ecosystems have low rates of productivity. Therefore, it is reasonable to seek the pronounced competitive value of the extremely slow-growing corallines. Due to their low annual growth increment, the coralline algae studied are very endangered by abiotic physical disturbances and by overgrowth of rapidly growing filamentous algae or sessile invertebrates. To overcome fouling pressure and storm-triggered physical disturbances, coralline algae thrive well in wave-sheltered headlands or skerry areas and generate characteristic ‘denuded areas’ by intense herbivory. This general distributional pattern is also true for high-boreal to subarctic coralline algal bioherms in northern Norway. Such a complex biological feedback maintains a high potential of self-regulation or self-organization in the algal reef bioherms. The different proponents involved in feedback processes include bacterial colonization, diatom microfouling and selective induction of larval metamorphosis. The negative impact of diatom microfouling and the important role of herbivores are relevant activities in the feedback system on a microscopic scale. Macroscopically, intense herbivory on coralline algae create denuded conditions, which are a widespread phenomenon in coralline algal ecosystems.     

Patterns of scleractinian coral recruitment at Lord Howe Island,an isolated subtropical reef off eastern Australia

Changing oceanic conditions, particularly ocean warming and altered currents, can affect the reproductive success of corals. Improving the knowledge of coral reproductive processes at the marginal range limits of coral reefs is important for understanding the ecology of subtropical coral communities and the potential for coral species to expand their ranges in higher latitudes in the future. The extent of live coral cover around subtropical Lord Howe Island (LHI; 31°33′S, 159°05′E) approximately 600 km off the east coast of Australia, has been relatively stable over the last several decades; however, shifts in dominant species in the adult coral community have been reported. To examine the potential influences of recent altered currents and shifts in dominant scleractinian taxa within this community, this study examined spatial and seasonal variation of coral larval settlement at different habitats within the LHI reef lagoon. The study also assessed whether the assemblage of scleractinian corals settling at LHI has changed between 1990–1991 and 2011–2012. Mean densities of coral settlement in 2011–2012 (230 spat m^?2 yr^?1) were consistent with those reported in 1990–1991 and in other regions. However, changes in taxonomic composition were apparent with increases in the proportion of Acroporidae spat at some sites. Settlement of all taxa was highest over summer months, whereas during winter only one coral spat (Pocilloporidae) was detected. Coral settlement was highest and most taxonomically diverse at sites closest to the reef crest, where mortality of settled spat was also greatest. Rates of settlement were high compared with juvenile densities; hence, post-settlement mortality is also likely to be high. Post-settlement processes, influenced by local environmental conditions, are likely to be very important in structuring the adult coral communities within the LHI reef lagoon.     

Colonization of subtidal macroalgae in a fucalean-dominated algal assemblage,southwestern Australia

The influence of fucalean canopy species and dominant understory macroalgae on algal colonization was investigated to evaluate whether layering contributes to patterns in algal diversity. Patterns in recruitment were compared among total-clearing, understory-removal, canopy-removal, and undisturbed plots (plot area = 0.25 m²), using a randomized block design in depths <10 m and 10–20 m at Woody Island, Western Australia. To evaluate if propagules were available in the water column above the canopy layer, settlement plates (plate area = 0.04 m²) were deployed in depths <10 m, 10–20 m, and >20 m. A total of 198 macroalgal species was recorded. Biomass of the understory species Osmundaria prolifera Lamouroux and Botryocladia sonderi Silva was similar between canopy-removal and undisturbed plots. Diversity of macroalgae was similar in the presence and absence of a canopy layer. Taxa found in the canopy showed different patterns in recruitment. Cystoseiraceae recruited predominantly in total-clearings in both depth strata. Sargassaceae recruited most abundantly in depths <10 m. Density of canopy taxa on settlement plates was similar with depth (20–30 juveniles per plate), and juveniles were mainly Cystoseiraceae. In contrast to kelp beds or forests, patterns in algal colonization appeared to be maintained by environmental factors or processes other than the direct effects of layering in the subtidal fucoid-dominated assemblages at Woody Island. Handling editor: K. Martens     

Reproductive biology of wahoo, Acanthocybium solandri, off eastern Australia

A dearth of basic biological information for wahoo, Acanthocybium solandri, currently hinders the ability of scientists and managers to assess population sustainability and appropriately manage the dramatically increasing global catch. This study examined the gonads of 382 wahoo collected off eastern Australia during 2008–2011 to quantify their reproductive biology in the region. The overall sex ratio of the sample was 3.2:1 (females:males), however this differed significantly among fishing sectors and areas. The estimated fork length at which 50 % of female wahoo reach maturity was 1,046 mm. Similar to the Atlantic Ocean, female wahoo have a protracted summer spawning season during October-February. The mean spawning frequency of female wahoo was uncertain but may be approximately 2–3 days, with evidence of fish actively spawning on consecutive days. Batch fecundity of females was positively correlated with fish size and estimates ranged between 0.65 and 5.12 million oocytes. Relative fecundity was estimated at 122.0 (±9.7) oocytes per gram of ovary free body weight and did not differ with fish size or throughout the spawning season. Estimation of reproductive parameters such as size- and age-at-maturity may facilitate the construction of per-recruit stock assessments of wahoo in the region.     

Youngest early carboniferous (late Visean) shallow-water patch reefs in eastern Australia (Rockhampton Group, Queensland): Combining quantitative micro- and macro-scale data

Summary Although skeletal organisms have received most of the emphasis in studies on Phanerozoic roef history, the roles of non-skeletal (non-enzymatic) carbonates (e.g., synsedimentary cements, automicrite, microbialite, etc.) in reef framework construction are becoming increasingly better understood. One problem in understanding the role of non-enzymatic carbonates in reef construction has been the difficulty in recognizing them in reef facies. Whereas skeletal organisms commonly can be recognized and documented in the field, non-enzymatic carbonates may be recognizable only in thin section. This paper describes the application of a new sampling technique that allows the quantitative comparison of skeletal macrofauna and flora with associated non-enzymatic carbonates and other microfaunal/microfloral constituents. The technique involves the point counting of thin sections made from small diameter cores that are systematically recovered from grids and line transects that cover a reasonable area (m²) of reef facies. Small, shallow-water patch reefs are abundant in scattered oolitic intervals in the Lower Carboniferous strata of eastern Australia. The youngest known Carboniferous reefs in eastern Australia occur in uppermost Visean strata (limestone FC5) near the top of the Rockhampton Group, approximately 50 km west-northwest of Rockhampton, Queensland. The largest sampled reef was 15 m thick and 42 m in diameter, with synsedimentary relief above the sea floor of at least 2 m during the primary growth phase. The reef occurs within bioclasticoolitic grainstones representing a shallow shelf setting and consists of eight common framework microfacies: 1) coral boundstone; 2) bryozoan boundstone; 3) mixed crinoid-bryozoan boundstone; 4) tubular problematica boundstone; 5) sponge-automicrite boundstone; 6) encrusted thrombolite boundstone; 7) mixed automicrite boundstone; and 8) thrombolitic wackestone-packstone. Reef growth was initiated by automicrite-producing biofilms, sponges and a tubular problematic organism. Primary relief building was accomplished by automicrite-dominated frameworks and lithistid sponges, crinoids, and corals. Large cerioidAphrophyllum coral colonies had a heterogeneous distribution through the reef. The framework of the main relief-bearing portion of the reef consists on average of 44.4% automicrite and automicrite-bound detritus, excluding automicrite-bound sponge body fossils, and at most 19.6% skeletal organisms in growth position (minimum of 7.2%). If sponge body fossils are included as automicrite framework, because they are preserved only as a result of automicrite formation, the percentage of automicrite and bound sediment is 54.9%. A smaller sampled reef consisting of the same basic facies had 39.5% automicrite and automicrite-bound sediment in its fremework (50.2% including sponges) and, at most, 33.4% skeletal organisms in growth position (minimum of 22.7%). The greater volume of skeletal framework in the small reef reflects a greater proportion of large corals. Of framebuilding skeletal organisms, automicrite-preserved lithistid and other sponges and cerioid rugose corals provided the greatest volume. However, crinoid holdfasts were the most widespread skeletal framework components. The dominant framework facies are sponge-automicrite boundstone, encrusted thrombolite, boundstone, mixed automicrite boundstone, and coral boundstone. The reefs are similar in overall framework construction and ecological succession to slightly older Visean reefs in eastern Australia and to some of the late Visean reefs of northern England. Surprisingly, framework similarities also exist between the reefs and certain thrombolite-lithistid-coral reefs of the European Jurassic.     

Microbial mats associated with bryozoans (Coorong Lagoon, South Australia)

Summary Bryostromatolites are laminated carbonate rocks composed of bryozoan zoarial laminae. The laminated texture is frequently caused by patterns of bryozoan self overgrowth as a regular defensive tactic against microbial fouling. In the Coorong Lagoon (South Australia), another type of bryostromatolite is present where the laminated growth of the weakly calcifying bryozoan speciesConopeum aciculata is postmortally stabilized by cyanobacterial mats at the surface, and fungal mats settling in the zooecial cavities. A tough extracellular slime network produced by benthic cyanobacteria is a trap for sediment particles, provides a method of adhesion to the bryozoan substrate, and produces a biological lamination by the vertical stratification of dead bryozoan skeletons. These slimes are also important for the preservation of cell structures and for their fossilization. Seasonal fluctuations in salinity and water level are the most important regional control factors, causing a phase displacement in the growth optima of microbial mats and bryozoans, thereby resulting in a rigid bryostromatolitic fabric.     

Mesophilic Actinomycetes in the Natural and Reconstructed Sand Dune Vegetation Zones of Fraser Island, Australia

The natural coastal habitat of Fraser Island located in the State of Queensland, Australia, has been disturbed in the past for mining of the mineral sand ilmenite. Currently, there is no information available on whether these past mining disturbances have affected the distribution, diversity, and survival of beneficial soil microorganisms in the sand dunes of the island. This in turn could deleteriously affect the success of the natural regeneration, plant growth, and establishment on the sand dunes. To support ongoing restoration efforts at sites like these mesophilic actinomycetes were isolated using conventional techniques, with particular emphasis on the taxa previously reported to produce plant-growth-promoting substances and providing support to mycorrhizal fungi, were studied at disturbed sites and compared with natural sites. In the natural sites, foredunes contained higher densities of micromonosporae replaced by increasing numbers of streptomycete species in the successional dune and finally leading to complex actinomycete communities in the mature hind dunes. Whereas in the disturbed zones affected by previous mining activities, which are currently being rehabilitated, no culturable actinomycete communities were detected. These findings suggest that the paucity of beneficial microflora in the rehabilitated sand dunes may be limiting the successful colonization by pioneer plant species. Failure to establish a cover of plant species would result in the mature hind dune plants being exposed to harsh salt and climatic conditions. This could exacerbate the incidence of wind erosion, resulting in the destabilization of well-defined and vegetated successional dunal zones.     

Caesium-137 profiles in the sediments of a partial-meromictic lake on Great Sandy Island (Fraser Island), Queensland,Australia

Hidden Lake is a perched, brown-water lake located in the centre of Great Sandy Island (Fraser Is.), S.E. Queensland. It is highly acid (pH 4.0), oligotrophic and is thermally and chemically stratified for most of the year. The sediments revealed a ¹³⁷Cs profile which departed from the temporal pattern of ¹³⁷Cs fallout in Brisbane and was represented by an exponential increase of ¹³⁷Cs towards the surface sediments from ca. 32 cm depth. The possible causes of the divergent profile are discussed, including physical and biological mixing, lag in the transport of catchment material to the sedimentary basin, diffusion, recycling and biological concentration. It is hypothesised that a combination of the last four processes, with diffusion facilitated by the highly acid conditions, are the major causes of the observed ¹³⁷Cs profile. Possible recycling and bioconcentration of ¹³⁷Cs raises questions as to the validity of this method of dating in similar environmental conditions, and as to the interpretation of other palaeochemical data. These hypotheses are to be tested against profiles obtained from ¹⁴C, ²¹⁰Pb, ^239/240Pu analyses of the sediment, and the measurement of ¹³⁷Cs activity in the water and biota of the lake.     

Lower Carboniferous (middle Visean) foraminifers and algae from an interior sea,Southern Carnarvon Basin,Australia

A moderate diversity biota of foraminifers, algae and calcareous microproblematica is recorded from the Lower Carboniferous Yindagindy Formation within the intracratonic Southern Carnarvon Basin in Western Australia. Very shallow metahaline to hypersaline conditions are suggested. The palaeobotanical components are sporadic calcitarcha, tuberitinaceans, codiaceans Orthriosiphon? sp. 1, dasycladaleans? Koninckopora tenuiramosa, and algosponges Issinella devonica, Serrisinella cf. serrensis, Issinella? sp. 1, Kamaena cf. awirsi, Proninella? sp. and Stacheoides spp. The foraminiferal assemblage is dominated by a new koktjubinid taxon: Praekoktjubina yindagindyensis nov. gen., nov. sp. Subordinate associated foraminifers are more sporadic Salpingothurammina? sp. 1, Plectinopsis michelseni nov. gen., nov. sp., Rectopravina multifida nov. gen., nov. sp. (with 4 morphotypes), and scarce Endothyra spp. Despite many of these taxa being endemic, a middle Visean age is probable, based on: (1) the maximum global geographic extent of K. tenuiramosa reached during the middle Visean, (2) the disappearance of Plectinopsis nov. gen. in Palaeotethys and the Urals, and (3) the first occurrence of Praekoktjubina nov. gen. in Palaeotethys. An age no older than the middle Visean is supported by sparse conodonts from the Formation and comparison to episodes of carbonate deposition in the Bonaparte Basin, further north in the East Gondwana rift system. Absence of middle Visean archaediscoids may be due to high salinity. The following algal and foraminiferal families and superfamilies are emended: Scribroporellaceae (a lectotype is selected for Orthriosiphon saskatchewanense); Palaeospiroplectamminidae (due to the creation of Plectinopsis nov. gen.); Haplophragminoidea (due to the creation of Rectopravina nov. gen.); and Globivalvulinoidea and Koktjubinidae (due to the creation of Praekoktjubina nov. gen.).     

Towards eradication: The history and management of Bitou Bush on K'gari‐Fraser Island,Australia

Persistence and dedication over the long term has been a key to success in control of this Weed of National Significance on World Heritage Listed K'gari‐Fraser Island in Queensland, Australia. Systematic surveys and treatment show that the goal of Bitou Bush eradication is worthwhile and can inspire other such projects within the region and beyond.     

<Emphasis Type="Italic">Rogadius mcgroutheri</Emphasis>, a new species of flathead (Teleostei: Platycephalidae) collected from eastern Australia and New Caledonia

A new platycephalid, Rogadius mcgroutheri, is described on the basis of the specimens collected from eastern Australia and New Caledonia. Rogadius mcgroutheri is distinguished from other congeners by 11 second dorsal fin rays usually, 4 or 6–8 unbranched lower pectoral fin rays, larger orbital diameter, usually single preocular spine lacking the accessory spines on the anterior base, short antrorse preopercular spine, tooth band on palatine narrow, with 2 irregular tooth rows, body with indistinct or somewhat distinct brown blotches, and caudal fin with dark brown spots and bands.     

Efficacy of bird-baited traps placed at different heights for collecting ornithophilic mosquitoes in eastern Queensland, Australia

To compare the efficacy of bird-baited traps with standard CO₂-baited Centers for Disease Control (CDC) light traps for collecting ornithophilic mosquito species, seven Latin square trials were conducted at six urban sites in Cairns and Brisbane, Australia. Traps were placed 1 m above ground level and 5–10 m according to tree canopy height. CO₂-baited CDC traps consistently collected more mosquitoes of all species than the bird-baited traps at all locations. In Brisbane, CO₂-baited CDC traps placed at ground level collected significantly more Culex annulirostris Skuse than those at canopy height during two trials, and more Aedes vigilax (Skuse) and Ae. procax (Skuse) during one trial each. Conversely, in Cairns, CO₂-baited CDC traps placed in the tree canopy collected significantly more Cx. squamosus (Taylor) during two trials, and significantly more Aedeomyia catasticta Knab and Cx. cubiculi Marks during one trial each. Consistently low yields of ornithophilic species including Cx. australicus Dobrotworsky & Drummond and Cx. quinquefasciatus Say in all traps tested suggests the need to employ alternative trapping measures to target these species in urban areas.     

The fine structure of secondary pit connection formation between the red algal alloparasiteHolmsella australis and its red algal hostGracilaria furcellata

Summary Pit connections (PCs) develop between the parasitic red algaHolmsella and its hostGracilaria. Only parasite cells initiate the formation of host-parasite pit connections. The parasite produces a small connecting cell (termed the conjunctor cell) which moves through the cell wall to fuse with either an adjacent host or parasite cell. The parasite secondary PC, which forms between the conjunctor cell and the parasite cell, is structurally different from a parasite primary PC, and has the distinct structure of a host-parasite PC. Only if the conjunctor cell fuses with another parasite cell will the former parasite-conjunctor cell PC be altered to a typical parasite-parasite PC. If the conjunctor cell fuses with an adjacent host cell the PC continues to develop as host-parasite. Occasionally a conjunctor cell fails to fuse with an adjacent cell (whether host or parasite), and the conjunctor cell and PC eventually breakdown in the cell wall. The parasite overcomes several barriers in order to infect the host, including the formation of host-parasite PCs which appear to be a necessary component of the parasiticHolmsella-Gracilaria association.     

Modern cryptic microbialite/metazoan facies from Lizard Island (Great Barrier Reef,Australia) formation and concepts

Summary From shallow water caves of fringing reefs related to continental islands of the Lizard Island Section thrombolitic micritic microbialites were observed. The microbialites exhibit always a light decreasing facies succession. The succession starts with a coralgal community and ends with light independent microbial biofilms and benthos (coralline sponges). The sessile mineralized benthos community is constructed of crustose foraminifera, serpulids, thecidean brachiopods, bryozoans, and coralline sponges. The observed benthic community is very similar to those one observed in cryptic habitates of Aptian and Albian reefs of northern Spain. For longtime studies of the microbialite formation and growth rates of coralline sponges the specimens were stained in vivo, within their natural habitat with histochemical fluorochromes and nonfluorescent agents. Main results are a very slow growth of the microbialite and associated sponges (50–100 μm/y). Only few calcifying microbes are participators during microbialite formation. Calcifying acidic organic macromolecules are mainly responsible for microbialite formation by cementing detritical material. Fe/Mn-bacterial biofilms are responsible for strong corrosion of the microbialite. Beside the corrosive activity of the Fe/Mn-bacterial biofilms boring sponges (Aka, Cliona) are the main destructors. Geochemically the observed microbialites are composed of mainly high-Mg calcites and exhibit high positive δ¹³C (+3 to +4) values.     

Permian algae and algal microfacies from unayzah,quassim district,saudi arabia

Summary Late Permian bioclastic calcarenite beds of the middle Khuff Formation were sampled for their algal constituents near the city of Unayzah, Quassim district in central Saudia Arabia. The algal flora includes two species of udoteacean algae (Succodium difficile andSuccodium sp.), the dasycladacean algaMizzia velebitana and two species of red algae (Gymnocodium bellerophontis, Permocalculus plumosus). Other algal floral remains found forming isolated single layers which have generally been named algal microfacies. These include a phylloid microfacies, an oncoid microfacies and algal stromatolites. The Khuff Formation is well-known for its accumulation of non-associated gas and particularly for its oil accumulation in eastern Saudi Arabia and the Arabian Gulf states.     

Phytolith and starch analysis of sediment samples from two archaeological sites on Dauar Island,Torres Strait,northeastern Australia

Current archaeological research suggests that first human occupation of the Torres Strait Islands occurred sometime between 2500 and 3000 cal b.p., and evidence indicates that the development of agricultural mound-and-ditch systems occurred there after 1200 cal b.p. Although archaeological remains testify to the existence of a marine based subsistence economy prior to 1200 cal b.p., the potential presence of earlier prehistoric horticultural signatures has yet to be adequately examined. This study investigates such evidence through a preliminary application of fossil phytolith and starch grain analysis using excavated sediments from two archaeological sites on Dauar Island, eastern Torres Strait. The results show the early presence of yam (Dioscorea sp.), and Musa species not endemic to the island. The occurrence of these edible plant types in association with carbonised phytoliths and anthropogenic shell and bone deposits may be indicative of a combined insular horticultural and marine subsistence system on Dauar Island. We suggest that with a larger and appropriate phytolith reference set for the research area, there is a potential to more clearly define human induced changes to vegetation and patterns of subsistence in the Torres Strait Islands.