Microfacies and sequence stratigraphy of the Amapá Formation, Late Paleocene to Early Eocene, Foz do Amazonas Basin, Brazil

On the basis of thin-section studies of cuttings and a core from two wells in the Amapá Formation of the Foz do Amazonas Basin, five main microfacies have been recognized within three stratigraphic sequences deposited during the Late Paleocene to Early Eocene. The facies are: 1) Ranikothalia grainstone to packstone facies; 2) ooidal grainstone to packstone facies; 3) larger foraminiferal and red algal grainstone to packstone facies; 4) Amphistegina and Helicostegina packstone facies; and 5) green algal and small benthic foraminiferal grainstone to packstone facies, divisible locally into a green algal and the miliolid foraminiferal subfacies and a green algal and small rotaliine foraminiferal subfacies. The lowermost sequence (S1) was deposited in the Late Paleocene–Early Eocene (biozone LF1, equivalent to P3–P6?) and includes rudaceous grainstones and packstones with large specimens of Ranikothalia bermudezi representative of the mid- and inner ramp. The intermediate and uppermost sequences (S2 and S3) display well-developed lowstand deposits formed at the end of the Late Paleocene (upper biozone LF1) and beginning of the Early Eocene (biozone LF2) on the inner ramp (larger foraminiferal and red algal grainstone to packstone facies), in lagoons (green algal and small benthic foraminiferal facies) and as shoals (ooidal facies) or banks (Amphistegina and Helicostegina facies). Depth and oceanic influence were the main controls on the distribution of these microfacies. Stratal stacking patterns evident within these sequences may well have been related to sea level changes postulated for the Late Paleocene and Early Eocene. During this time, the Amapá Formation was dominated by cyclic sedimentation on a gently sloping ramp. Environmental and ecological stress brought about by sea level change at the end of the biozone LF1 led to the extinction of the larger foraminifera (Ranikothalia bermudezi).     

Coralline algae indicate Pleistocene evolution from deep,open platform to outer barrier reef environments in the northern Great Barrier Reef margin

Coralline algae from a drill core in Ribbon Reef 5 have been used to interpret changes in the depositional palaeoenvironments in the northern Australian Great Barrier Reef over the last 790 ka. Three main coralline algal assemblages, each dominated by members of a particular subfamily, have been distinguished by quantitative analysis: (1) mastophoroid assemblages, usually occurring as crusts on corals, are typical of the shallowest reef settings; (2) lithophylloid assemblages within algal nodules may represent shallow-water, cooler environments or deeper reef subenvironments; and (3) melobesioid assemblages are characteristic of deeper-water platform areas. The algal assemblages between 96 and 210 m b.s.f. (metre below sea floor) record a fluctuating but progressive shallowing-upwards from deep, outer-platform to shallower, non-reefal depositional environments. Two intervening episodes dominated by mastophoroids represent two phases of reef growth. The section above 96 m b.s.f. comprises several stacked reefs in which mastophoroid crusts similar to the present-day shallow-water assemblages predominate.Electronic Supplementary Material Supplementary material is available for this article at .Communicated by: Geological Editor P.K. Swart     

Late Holocene reef growth and relative sea-level changes in Atol das Rocas, equatorial South Atlantic

Shallow drilling provided the first detailed record of vertical reef accretion rates for the last 4,000 years from the oceanic atoll Atol das Rocas. Six cores up to1-m long from windward, leeward, and intertidal hardground environments were radiocarbon dated. Frameworks are dominated by the coralline alga Porolithon cf. pachydermum with minor contributions of Lithophyllum sp. Coralline bindstone and framestone facies were identified. Vertical accretion rates (VAR) form three groups: group A frameworks were formed between 3,490±45 years BP and 2,770±45 years BP, and VAR are 0.85, 1.4, and 1.6 mm/year; group B frameworks were formed between 2,510±45 year BP and 490±45 year BP, and VAR are 0.25, 0.46, and 0.42 mm/year; group C frameworks were formed between 900±50 year BP and 655±45 year BP, and VAR are 3.2, 9.75, and 18.4 mm/year. Results indicate that coralline-algal reefs may display a catch-down response to a falling sea level similar to the way corals respond to a rising sea level. In this case, present day reef topography may be the result of late Holocene SW Atlantic sea-level changes. The calculated VAR of 18.4 mm/year is the highest rate known to date for a coralline-algal reef and close to the maximum rates recorded for corals.     

Coralline-algal assemblages of a Burdigalian platform slope: implications for carbonate platform reconstruction (northern Sardinia,western Mediterranean Sea)

The rhodolithic slope deposits of a Burdigalian carbonate platform in Sardinia near Sedini were analyzed to reconstruct facies and palaeobathymetry. There is a distinct red-algal growth zonation along the platform slope. The clinoform rollover area consists of coralline-algal bindstones, which downslope change into a zone where rhodoliths are locally fused by progressive encrustation. Mid-slope rhodoliths are moderately branched, and downslope rhodoliths have fruticose protuberances, resulting in branching rhodolith growth patterns. There is a sharp change from the rhodolitic rudstones to the basinal, bivalve-dominated rudstones at the clinoform bottomsets. Red-algal genera identified include Sporolithon, Lithophyllum, Spongites, Hydrolithon, Mesophyllum, Lithoporella, Neogoniolithon, and other mastophoroids and melobesioids. Genera and subfamilies show a zonation along the clinoforms, allowing palaeobathymetric estimates. The clinoform rollovers formed at a water depth of around 40 m and the bottomsets around 60 m. Results from geometrical reconstruction show that coral reefs in the inner platform formed at water depths of around 20 m. Therefore, the Sedini carbonate platform is an example of a reef-bearing platform in which the edge or the platform-interior reefs do not build up to sea level.     

Clonal architecture in marine macroalgae: ecological and evolutionary perspectives

The study of the ecological and evolutionary consequences of clonal growth in vascular plants has been widely addressed; however, marine macroalgae, which are interesting modular organisms that combine simple morphologies and complex life cycles, have been almost ignored. This paper presents a review and analysis of the ecological and evolutionary consequences of clonality in marine macroalgae, including three main subjects: (1) modular construction (modules and ramets); (2) life cycle and evolutionary perspectives, and (3) ecological perspectives of clonality in marine macroalge. The biological emergent attributes of clonality are present in marine macroalgae e.g. high longevity of the genet by the continual renewal of modules, and variable morphological plasticity of ramets and modules in relation to environmental conditions. However, experimental work is still needed to solve questions such as the effect of crowding on survival rates and use of resources, as well as its effect on sexual or asexual patterns of reproduction. I expect that the study of the evolutionary consequences of the combined presence of alternation of generations and clonal growth in marine macroalgae will make important contributions to clonal plant theory.     

Competition between scleractinian corals and macroalgae: An experimental investigation of coral growth, survival and reproduction

Macroalgae are a major component of many coral reef flat communities, and are potentially major competitors with corals. The influence of macroalgae on several demographic parameters of four species of scleractinian coral by means of an algal clearance experiment was examined to determine specifically if macroalgae are affecting coral cover, growth, fecundity, fission, survivorship and recruitment. Also investigated were patterns of natural encounters between corals and algae.

Algal cover at the study site ranged from 41 to 56%, and coral cover from 8 to 10%. In total, 92 ± 4 ( )% of coral colonies were in contact with one or more species of macroalgae. Changes in coral cover were significantly affected by the presence of macroalgae, with cover of Acropora species increasing faster in areas from which algae had been cleared compared to control areas where algae had not been removed, although this pattern did not occur for Pocillopora damicornis (Linnaeus). Similarly, growth of individual colonies was faster when macroalgae were absent for three Acropora species but not for P. damicornis. There were no differences detected in rates of fission or survivorship of corals between algal clearance and control treatments, although there were high levels of variability in both of these parameters. Fecundity of Acropora palifera (Lamarck), the only species examined, was approximately double in colonies in cleared plots compared to those in control plots with macroalgae present. As no recruitment occurred throughout the 2-yr study, it remains to be determined how macroalgae effect the settlement of coral larvae. The results show that macroalgae can have a major influence on the demography of scleractinian corals.     

海洋微生物及海藻抗HIV天然产物研究进展

艾滋病是当今重大的公共卫生问题和社会问题。从天然资源寻找新抗HIV活性天然产物是新药发现的重要途径。综述了来源于海洋微生物、海藻具抗HIV活性的天然产物以及抗H1V活性天然产物筛选方法和靶点。     

Reevaluating sponge diversity and distribution in the Mediterranean Sea

The aim of this paper was (1) to update sponge diversity and distribution in the Mediterranean and (2) to re-examine faunal relationships among the Mediterranean areas on the basis of their sponge fauna. The Mediterranean demosponge faunal list was updated to 629 species by taking into consideration recent data from previously poorly studied areas. The species lists of 14 Mediterranean areas were compared on the basis of their sponge species richness, species composition, and taxonomic relatedness of species using multivariate analyses and diversity measures, such as PD, Delta+, and Lambda+. The 14 Mediterranean areas examined for their diversity and affinities were assembled into four major zoogeographic groups: the northwestern, northeastern, the central zone, and southeastern areas. Richest in species numbers were the areas belonging to the two northern groups. The species richness comparisons and similarity analyses performed at the generic level showed that it can be safely used as a surrogate for sponge species diversity in the Mediterranean. The results of this study showed that the simple traditional division of the Mediterranean Sea into a western, central, and eastern basin cannot reliably describe the distribution of sponges in the area. Thus, the W to E faunal decline previously presented for several faunal groups shifts to a general NNW-SSE pattern when one examines separately the northern and the southern parts of the traditional basins. This gradient seems to be in agreement with differences in key environmental variables, such as latitude, salinity, temperature, and water circulation, besides the typically examined distance from Gibraltar. Handling editor: T. P. Crowe     

Ethanol production from marine algal hydrolysates using Escherichia coli KO11

Algae biomass is a potential raw material for the production of biofuels and other chemicals. In this study, biomass of the marine algae, Ulva lactuca, Gelidium amansii,Laminaria japonica, and Sargassum fulvellum, was treated with acid and commercially available hydrolytic enzymes. The hydrolysates contained glucose, mannose, galactose, and mannitol, among other sugars, at different ratios. The Laminaria japonica hydrolysate contained up to 30.5% mannitol and 6.98% glucose in the hydrolysate solids. Ethanogenic recombinant Escherichia coli KO11 was able to utilize both mannitol and glucose and produced 0.4 g ethanol per g of carbohydrate when cultured in L. japonica hydrolysate supplemented with Luria-Bertani medium and hydrolytic enzymes. The strategy of acid hydrolysis followed by simultaneous enzyme treatment and inoculation with E. coli KO11 could be a viable strategy to produce ethanol from marine alga biomass.     

Responses of marine organisms to physical and chemical impacts

Studies on the effects of a variety of exogenous and anthropogenic environmental factors, including endocrine disruptors, heavy metals, UV light, high temperature, and others, on marine organisms have been presented at the 2nd Bilateral Seminar Italy–Japan held in November 2006. Reports were discussed in order to reveal the current situation of marine ecosystems, aiming at evaluation and prediction of environmental risks.

Ocean acidification and calcifying reef organisms: a mesocosm investigation

A long-term (10 months) controlled experiment was conducted to test the impact of increased partial pressure of carbon dioxide (pCO₂) on common calcifying coral reef organisms. The experiment was conducted in replicate continuous flow coral reef mesocosms flushed with unfiltered sea water from Kaneohe Bay, Oahu, Hawaii. Mesocosms were located in full sunlight and experienced diurnal and seasonal fluctuations in temperature and sea water chemistry characteristic of the adjacent reef flat. Treatment mesocosms were manipulated to simulate an increase in pCO₂ to levels expected in this century [midday pCO₂ levels exceeding control mesocosms by 365 ± 130 μatm (mean ± sd)]. Acidification had a profound impact on the development and growth of crustose coralline algae (CCA) populations. During the experiment, CCA developed 25% cover in the control mesocosms and only 4% in the acidified mesocosms, representing an 86% relative reduction. Free-living associations of CCA known as rhodoliths living in the control mesocosms grew at a rate of 0.6 g buoyant weight year⁻¹ while those in the acidified experimental treatment decreased in weight at a rate of 0.9 g buoyant weight year⁻¹, representing a 250% difference. CCA play an important role in the growth and stabilization of carbonate reefs, so future changes of this magnitude could greatly impact coral reefs throughout the world. Coral calcification decreased between 15% and 20% under acidified conditions. Linear extension decreased by 14% under acidified conditions in one experiment. Larvae of the coral Pocillopora damicornis were able to recruit under the acidified conditions. In addition, there was no significant difference in production of gametes by the coral Montipora capitata after 6 months of exposure to the treatments.     

Coralline red algal assemblage from the Middle Pliocene shallow-water temperate carbonates of the Monte Cetona (Northern Apennines,Italy)

During the Pliocene and Pleistocene, the Monte Cetona (Northern Apennines, central Italy) was part of an elongated island. The Middle Pliocene deposits around the Monte Cetona are represented by shallow-water marine carbonates rich in coralline red algae and bryozoans. These skeletal carbonates, characterising a coralline algal-dominated factory, were analysed in terms of microfacies, taxonomy, and growth-forms of coralline red algal assemblage. Three microfacies were distinguished on the basis of component distribution and fabric analysis: coralline algal rudstones, coralline algal floatstones, and bioclastic packstones. Skeletal components are commonly abraded, bioeroded, and encrusted. The shallow-water skeletal carbonates are strongly bioturbated and any primary sedimentary structure is obliterated. The distribution of the coralline growth-forms suggests a decreasing hydrodynamic gradient from the coralline algal rudstone, through the coralline algal floatstone to the bioclastic packstone microfacies. The coralline algal flora consists of eight species representing the subfamilies Lithophylloideae, Mastophoroideae and Melobesioideae. The assemblage is dominated by lithophylloids. Other biogenic components are bryozoans, barnacles, echinoderms, and benthic foraminifera. These coralline algal assemblages were deposited just above the fair-weather wave base and indicate a shallow-marine temperate water setting for the eastern Tyrrhenian Sea during the Mid Pliocene.     

Outdoor cultivation of sea vegetables

Summary The outdoor cultivation of sea vegetables is carried out on a large scale in the Orient, mainly in Japan, China, Taiwan, Korea and the Philippines. Food crops are the most important among the sea vegetables cultivated, with Porphyra and Undaria being the more important in Japan and Laminaria in China. Eucheuma, an industrial crop containing the phycocolloid carrageenan, is cultivated in wide areas of the Philippines. The cultivation of the major food crops, which developed quickly over the past 30 years, is largely based on the results of research, especially with regard to seeding procedures, which have reached a certain level of sophistication.The major crops of sea vegetables are cultivated attached to ropes or nets located in a suitable site and habitat. Crops of limited economic value, however, are still cultivated by the old, primitive method of planting on stones on the ocean bed and other similar means. The location and timing of farming are selected with regard to the requirements of the plants for light, temperature, water movement, exposure to air (for the intertidal species),etc. Cultivation of seeding material of the three food crops and seeding of ropes and nets is carried out indoors under more or less controlled conditions. When the sporelings become established they are transferred to cultivation grounds in the ocean. When the plantlets grow too densely (in Laminaria) they have to be separated and replanted at the correct distances. This is done several weeks after transplantation to the ocean, when they are large and sufficiently strong. Eucheuma and other industrial crops are propagated vegetatively, using cuttings and fragments as planting material. Where seawater is lacking in nutrients, fertilizers are applied to guarantee a higher yield. The harvest is carried out manually, except for Porphyra, for which mechanical harvesters are used. Sea vegetables are attacked by pathogens that may cause severe damage to the crops. Diseases caused by improper growing conditions are also known. Grazers may also inflict losses. In all major crops the strains cultivated have been selected. In a few cases hybridization and other genetic techniques have been used to obtain domesticated varieties that can grow and yield far beyond the limits of their wild-type parents.Despite the fact that some mechanization has been introduced into the cultivation of sea vegetables, it is still by and large a highly labor-intensive enterprise. Nevertheless, it competes well with terrestrial crops in the Orient from the economic point of view.Interest in the cultivation of sea vegetables is widespread in the West and much experimental work aimed at its materialization has been underway during the lastca. twenty years.     

Temperature responses of economically important red algae and their potential for mariculture in Brazilian waters

Data are presented on temperature responses, based onin vitro growth performance, of eight species of colloid-producing red algae; these include the five most important commercial species of agarophytes in South America. The temperature optima do not conform strictly to geographic distribution, and intolerance to high temperature is not the factor that controls the spreading of temperate species ofGracilaria to warmer areas. WithinPterocladia capillacea (Gmelin) Bornet et Thuret, populations from two distinct localities had different responses to temperature optima. Data suggest that the disjunct distribution of this species in the American Atlantic is due to its poor performance at temperatures above 26 °C. The fastest maximum growth rate was observed inHypnea cornuta (Lamouroux) J. Agardh (doubling time 2.8 d), and the slowest inP. capillacea from Cabo Frio (doubling time 50.0 d). All the species studied, including the valuable Chilean and Argentinean species ofGracilaria, could tolerate the temperature regimes of the Brazilian waters.     

Antibiotic activity of lectins from marine algae against marine vibrios

Saline and aqueous ethanol extracts of marine algae and the lectins from two red algal species were assayed for their antibiotic activity against marine vibrios. Experimental studies were also carried out on the influence of environmental factors on such activity, using batch cultures. The results indicated that many of the saline extracts of the algal species were active and that the activity was selective against those vibrios assayed. The algal extracts were active against Vibrio pelagius and the fish pathogen V. vulnificus, but inactive against V. neresis. Algal lectins from Eucheuma serra (ESA) and Galaxaura marginata (GMA) strongly inhibited V. vulnificus but were inactive against the other two vibrios. The antibacterial activity of algal extracts was inhibited by pretreatment with various sugars and glycoprotein. Extracts of the two red algae, E. serra and Pterocladia capillacea, in saline and aqueous ethanol, inhibited markedly the growth rate of V. vulnificus at very low concentrations. Culture results indicated that metabolites active against V. vulnificus were invariably produced in P. capillacea over a wide range of temperature, light intensity, and nutritional conditions. Enhanced antibacterial activity occurred when P. capillacea was grown under higher irradiance, severe nutrient stress and moderate temperature (20 °C), reflecting the specific antibiotic characteristics of this alga. The strong antibiotic activity of lectins towards fish pathogenic bacteria reveals one of the important roles played by algal lectins, as well as the potential high economic value of those marine algae assayed for aquaculture and for biomedical purposes.