Distribution of living planktonic foraminifera in the Ross Sea and the Pacific sector of the Southern Ocean (Antarctica)

In order to determine the factors controlling the distribution of planktonic foraminifera as a proxy for reconstruction of paleoenvironments, we present data on live assemblages collected in the Southern Ocean. Plankton tows and hydrographic measurements were taken in the upper 400 m of the water column at different sites in the Ross Sea (site B) and at the Polar Front of the Pacific Ocean (site O) during austral summers from 1998 to 2003.Based on qualitative micropaleontological observations we discriminated between Neogloboquadrina pachyderma dextral (dex) and N. pachyderma sinistral (sin). In addition for N. pachyderma (sin) we distinguished four morphs: the first one (1) has a thickened test and depressed sutures; the second morph (2) is represented by specimens characterized by a subspheric and heavily encrusted test; the third morph (3) has a thin and lobate walled test; the fourth one (4) represent the juvenile stage of N. pachyderma (sin) and is characterized by a smaller average size.The microfauna collected in the Ross Sea (site B) is characterized by the dominance of N. pachyderma (sin) (morphs 1 and 2), whereas low occurrences of Turborotalia quinqueloba, N. pachyderma (dex) and Neogloboquadrina dutertrei were noted in the first 50 m of the water column. The water column at this station is characterized by a marked and shallow stratification and a marked thermocline during the sampling season.At the ocean station (site O), the assemblage shows increasing diversification: T. quinqueloba, G. bulloides, N. pachyderma (dex) and few specimens of Globigerinita uvula characterize the planktonic microfauna. There is a predominance of non-encrusted morphs and juvenile specimens (3 and 4). At this station the mixed surface layer is deeper than in the Ross Sea (60–70 m), the pycnocline and the thermocline less marked.The depth and the intensity of the Deep Chlorophyll Maximum (DCM) influence foraminiferal distribution: N. pachyderma (sin) shows abundance peaks at or just below the DCM while G. bulloides peaks above the DCM. Coiling direction of N. pachyderma seems to be not controlled exclusively by Sea Surface Temperature (SST): probably the two coiling types are genetically different.Results document that diversity of planktonic foraminifera, number of specimens and variations in test morphology are related to regional differences in water properties (temperature, salinity, and DCM depth).     

Retinal topography of ganglion cells in immature ocean sunfish, <Emphasis Type="Italic">Mola mola</Emphasis>

The ocean sunfish, Mola mola, is the largest known bony fish. Based on prior studies of diet composition, it is considered to be a pelagic zooplanktivore. However, a recent study using acoustic telemetry revealed that they repeatedly dive to depths of >50 m during the day. We examined the distribution of cells within the retinal ganglion cell layer in the immature ocean sunfish (c.a. 50 cm total length) and estimated their visual acuity with respect to the main visual axis and visual fields. Visual acuity was between 3.37 and 4.41 cycles/degree. The region of highest cell density was located in the dorso-temporal retina, indicating that the main visual axis of ocean sunfish is directed towards the lower frontal portion of the visual field. This axis is considered beneficial for detecting prey items when the sunfish are migrating vertically through the water column, and in foraging behavior near the sea bottom.     

缅甸英雄岛始新世-上新世浮游有孔虫及其古环境意义

英雄岛位于印度洋缅甸西海岸,前人在该区所做的工作较少,生物地层研究程度较低.围绕该区石油勘探的进行,作者分析了RM19-3-1井的29件钻井岩屑样品,根据所含浮游有孔虫识别出7次有孔虫生物事件.考虑到研究区处于低纬度地区,故采用Bolli和Saunders(1985)的分带标准建立了7个浮游有孔虫化石带:P12-P17带;P18/19-P21/N2带;P22/N3带,N4-N7带;N8-N10带;N11-N14带和N15-N20?带,其延限时代为始新世-上新世.根据所含有孔虫动物群的演替规律,可将研究区的沉积环境变化由下而上划分为6个阶段,总体具有大陆架-陆坡的沉积环境特征.     

Extracellular hydrolytic enzyme screening of culturable heterotrophic bacteria from deep-sea sediments of the Southern Okinawa Trough

The Southern Okinawa Trough is an area of focused sedimentation due to particulate matter export from the shelf of the East China Sea and the island of Taiwan. In order to understand the geomicrobiological characteristics of this unique sedimentary environment, bacterial cultivations were carried out for an 8.61 m CASQ core sediment sample. A total of 98 heterotrophic bacterial isolates were characterized based on 16S rRNA gene phylogenetic analysis. These isolates can be grouped into four bacterial divisions, including 13 genera and more than 20 species. Bacteria of the γ-Proteobacteria lineage, especially those from the Halomonas (27 isolates) and Psychrobacter (20 isolates) groups, dominate in the culturable bacteria assemblage. They also have the broadest distribution along the depth of the sediment. More than 72.4% of the isolates showed extracellular hydrolytic enzyme activities, such as amylases, proteases, lipases and Dnases, and nearly 59.2% were cold-adapted exoenzyme-producers. Several Halomonas strains show almost all the tested hydrolases activities. The wide distribution of exoenzyme activities in the isolates may indicate their important ecological role of element biogeochemical cycling in the studied deep-sea sedimentary environment.     

Climate change and coral reefs: Trojan horse or false prophecy?

Maynard et al. (Coral Reefs 27:745–749, 2008a) claim that much of the concern about the impacts of climate change on coral reefs has been “based on essentially untested assumptions regarding reefs and their capacity to cope with future climate change”. If correct, this claim has important implications for whether or not climate change represents the largest long-term threat to the sustainability of coral reefs, especially given their ad hominem argument that many coral reef scientists are guilty of “popularising worst-case scenarios” at the expense of truth. This article looks critically at the claims made by Maynard et al. (Coral Reefs 27:745–749, 2008a) and comes to a very different conclusion, with the thrust and veracity of their argument being called into question. Contrary to the fears of Grigg (Coral Reefs 11:183–186, 1992), who originally made reference to the Cassandra syndrome due to his concern about the sensationalisation of science, the proposition that coral reefs face enormous challenges from climate change and ocean acidification has and is being established through “careful experimentation, long-term monitoring and objective interpretation”. While this is reassuring, coral reef ecosystems continue to face major challenges from ocean warming and acidification. Given this, it is an imperative that scientists continue to maintain the rigour of their research and to communicate their conclusions as widely and clearly as possible. Given the shortage of time and the magnitude of the problem, there is little time to spare.     

Invasive Ants Disrupt Gecko Pollination and Seed Dispersal of the Endangered Plant Roussea simplex in Mauritius

In Mauritius, the endemic blue-tailed day-gecko Phelsuma cepediana is currently the sole pollinator and seed disperser of the critically endangered endemic plant Roussea simplex (Rousseaceae). The flowers and fruits are often visited by the invasive ant Technomyrmex albipes , which forages on the nectar and fruit pulp, and tends honeydew-producing mealybugs on the fruits. Here, we experimentally explore how the presence of this alien ant species influences geckos foraging at flowers and fruits of R. simplex by removing and excluding ants from flowers and fruits. Gecko visitation rates to ant-free control flowers and fruits, and flowers and fruits where ants had been removed and excluded, were higher than those to ant-infested flowers and fruits. The resulting seed set of ant-infested flowers was greatly reduced, compared to ant-free control flowers. Similarly, for fruits with ants, very few seeds were likely to be ingested and dispersed by the geckos. Thus, T. albipes monopolizes flowers and fruits of R. simplex , and prevents access of pollinating and seed-dispersing P. cepediana geckos by aggressive interference competition. For a critically endangered plant like R. simplex , this double-disruption of two vital mutualistic interactions is of urgent conservation concern.     

<Emphasis Type="Italic">Myzostoma fuscomaculatum</Emphasis> (Myzostomida), a new myzostome species from False Bay,South Africa

A new myzostome species, described here as Myzostoma fuscomaculatum n. sp. was collected on Tropiometra carinata in False Bay (South Africa), during a survey of symbionts associated with comatulid crinoid species. M. fuscomaculatum n. sp. occurred only on T. carinata and not on the more common crinoid, Comanthus wahlbergi. It infested 61.7% of the 120 host specimens collected, of which 64.9% (48 specimens) hosted more than one individual (maximum of 32). M. fuscomaculatum n. sp. was always located on the host’s arms and pinnules and was cryptically coloured, closely matching the colour pattern of the host. This is the first record of myzostomes from the cool temperate waters of South Africa’s Atlantic coast. The new species is morphologically close to M. gopalai Subramaniam, 1938, collected on T. encrinus in Madras Harbour. M. fuscomaculatum n. sp. differs from M. gopalai in lacking marginal cirri at the adult stage, the presence of three pairs of digestive diverticula, by the position of its lateral organs and by the shape of the manubrium. Molecular phylogenetic analyses based on 18S and 16S rDNA placed M. fuscomaculatum n. sp. into a clade including Hypomyzostoma, Myzostoma and Mesomyzostoma species. Handling editor: K. Martens Déborah Lanterbecq and Tessa Hempson contributed equally to this work.     

Fishes of the family Ipnopidae (Teleostei: Aulopiformes) collected on the Brazilian continental slope between 11° and 23° S

A collection of fishes from the Brazilian continental slope between 11° and 23° S obtained through trawling revealed nine species of Ipnopidae. Bathypterois bigelowi and Bathytyphlops marionae represent first records from the south-western Atlantic Ocean and Bathypterois grallator is reported off Brazil for the first time. Four species have their distribution extended in Brazilian waters: Bathypterois phenax , Bathypterois quadrifilis , Bathypterois viridensis and Ipnops murrayi . An identification key of Ipnopidae species from the south-western Atlantic Ocean is included.     

Whisker isotopic signature depicts migration patterns and multi-year intra- and inter-individual foraging strategies in fur seals

The movement and dietary history of individuals can be studied using stable isotope records in archival keratinous tissues. Here, we present a chronology of temporally fine-scale data on the trophic niche of otariid seals by measuring the isotopic signature of serially sampled whiskers. Whiskers of male Antarctic fur seals breeding at the Crozet Islands showed synchronous and regular oscillations in both their δ¹³C and δ¹⁵N values that are likely to represent their annual migrations over the long term (mean 4.8 years). At the population level, male Antarctic fur seals showed substantial variation in both δ¹³C and δ¹⁵N values, occupying nearly all the ‘isotopic space’ created by the diversity of potential oceanic habitats (from high Antarctica to the subtropics) and prey (from Antarctic krill to subantarctic and subtropical mesopelagic fishes). At the individual level, whisker isotopic signatures depict a large diversity of foraging strategies. Some seals remained in either subantarctic or Antarctic waters, while the migratory cycle of most animals encompassed a wide latitudinal gradient where they fed on different prey. The isotopic signature of whiskers, therefore, revealed new multi-year foraging strategies of male Antarctic fur seals and is a powerful tool for investigating the ecological niche during cryptic stages of mammals'' life.