Benthic foraminifera asemblages and isotopic composition of surface sediment samples off Morocco

The influence of different primary productivity regimes on live (Rose Bengal stained) and dead benthic foraminiferal distribution, as well as on the stable carbon isotopic composition of foraminiferal tests, was investigated in sediment surface samples (0-1 cm) from the upwelling region off Morocco between Cape Ghir (31°N) and Cape Yubi (27°N). A combination of factor analysis, detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) was applied to the benthic foraminiferal data sets. Five major assemblages for both the live and dead fauna were revealed by factor analysis. In the cape regions organic matter fluxes are enhanced by high chlorophyll-a concentrations in the overlying surface waters. Here, benthic foraminiferal faunas are characterized by identical live and dead assemblages, high standing stocks, and low species delta13C values, indicating constant year-round high productivity. Bulimina marginata dominates the unique fauna at the shallowest station off Cape Ghir indicating highest chlorophyll-a concentrations. Off both capes, the succession of the Bulimina aculeata/Uvigerina mediterranea assemblage, the Sphaeroidina bulloides/Gavelinopsis translucens assemblage, and the Hoeglundina elegans assemblage from the shelf to the deep sea reflects the decrease in chlorophyll-a concentrations, hence the export flux. In contrast, the area between the capes is characterized by differently composed live and dead assemblages, low standing stocks, and less depleted delta13C values, thus reflecting low primary productivity. High foraminiferal numbers of Epistominella exigua, Eponides pusillus, and Globocassidulina subglobosa in the dead fauna indicate a seasonally varying primary productivity signal. Significantly lower mean delta13C values were recorded in Bulimina mexicana, Cibicidoides kullenbergi, H. elegans, U. mediterranea and Uvigerina peregrina. Cibicidoides wuellerstorfi is a faithful recorder of bottom water delta13C in the Canary Islands regions. The mean delta13C signal of this species is not significantly influenced by constant high organic matter fluxes. The species-specific offset between live and dead specimens is the same.

Benthic foraminifera assemblages of the Gulf of Aden

Benthic and selected planktic foraminifera and stable isotope records were determined in a piston core from the Gulf of Aden, NW Arabian Sea that spans the last 530 ka. The benthic foraminifera were grouped into four principal assemblages using Q-mode Principal Component Analyses. Comparison of each of these assemblages with the fauna of the nearby regions enabled us to identify their specific environmental requirements as a function of variability in food supply and strength of the oxygen minimum zone and by that to use them as indicators of surface water productivity. The benthic foraminiferal productivity indicators coupled with the record of Globigerina bulloides, a planktic foraminifer known to be sensitive to productivity changes in the region, all indicate higher productivity during glacial intervals and productivity similar to present or even reduced during interglacial stages. This trend is opposite to the productivity pattern related to the SW summer monsoon of the Arabian Sea and indicates the role of the NE winter monsoon on the productivity of the Gulf of Aden. A period of exceptionally enhanced productivity is recognized in the Gulf of Aden region between ~60 and 13 kyr indicating the intensification of the NE winter monsoon to its maximal activity. Contemporaneous indication of increased productivity in other parts of the Arabian Sea, unexplained so far by the SW summer monsoon variability, might be related to the intensification of the NE winter monsoon. Another prominent event of high productivity, second in its extent to the last glacial productivity event is recognized between 430 and 460 kyr. These two events seem to correspond to periods of similar orbital positioning of rather low precession (and eccentricity) amplitude for a relatively long period. Glacial boundary conditions seem to control to a large extent the NE winter monsoon variability as also indicated by the dominance of the 100 ka cycle in the investigated time series. Secondary in their importance are the 23 and 41 ka cycles which seem also to contribute to the NE monsoonal variability. Following the identification of productivity events related to the NE winter monsoon in the Gulf of Aden, it is possible now to extend this observation to other parts of the Arabian Sea and consider the contribution of this monsoonal system to the productivity fluctuations preserved in the sedimentary records.

Comparative phylogeography of the western Indian Ocean reef fauna

Assessing patterns of connectivity at the community and population levels is relevant to marine resource management and conservation. The present study reviews this issue with a focus on the western Indian Ocean (WIO) biogeographic province. This part of the Indian Ocean holds more species than expected from current models of global reef fish species richness. In this study, checklists of reef fish species were examined to determine levels of endemism in each of 10 biogeographic provinces of the Indian Ocean. Results showed that the number of endemic species was higher in the WIO than in any other region of the Indian Ocean. Endemic species from the WIO on the average had a larger body size than elsewhere in the tropical Indian Ocean. This suggests an effect of peripheral speciation, as previously documented in the Hawaiian reef fish fauna, relative to other sites in the tropical western Pacific. To explore evolutionary dynamics of species across biogeographic provinces and infer mechanisms of speciation, we present and compare the results of phylogeographic surveys based on compilations of published and unpublished mitochondrial DNA sequences for 19 Indo-Pacific reef-associated fishes (rainbow grouper Cephalopholis argus, scrawled butterflyfish Chaetodon meyeri, bluespot mullet Crenimugil sp. A, humbug damselfish Dascyllus abudafur/Dascyllus aruanus, areolate grouper Epinephelus areolatus, blacktip grouper Epinephelus fasciatus, honeycomb grouper Epinephelus merra, bluespotted cornetfish Fistularia commersonii, cleaner wrasse Labroides sp. 1, longface emperor Lethrinus sp. A, bluestripe snapper Lutjanus kasmira, unicornfishes Naso brevirosris, Naso unicornis and Naso vlamingii, blue-spotted maskray Neotrygon kuhlii, largescale mullet Planiliza macrolepis, common parrotfish Scarus psicattus, crescent grunter Terapon jarbua, whitetip reef shark Triaenodon obesus) and three coastal Indo-West Pacific invertebrates (blue seastar Linckia laevigata, spiny lobster Panulirus homarus, small giant clam Tridacna maxima). Heterogeneous and often unbalanced sampling design, paucity of data in a number of cases, and among-species discrepancy in phylogeographic structure precluded any generalization regarding phylogeographic patterns. Nevertheless, the WIO might have been a source of haplotypes in some cases and it also harboured an endemic clade in at least one case. The present survey also highlighted likely cryptic species. This may eventually affect the accuracy of the current checklists of species, which form the basis of some of the recent advances in Indo-West Pacific marine ecology and biogeography.

Anatomia foliar das espécies brasileiras de Mikania Willdenow seção Globosae Robinson: visão farmacognóstica.

O gênero Mikania Willdenow, criado em 1803, possui atualmente cerca de 300 espécies das quais 152 ocorrem no Brasil. São Paulo, Minas Gerais e Rio de Janeiro correspondem ao maior centro de dispersão. A maioria das espécies deste gênero possui emprego na medicina popular merecendo destaque as conhecidas pelo nome de guaco. Mikania hirsutissima DC e M. glomerata Sprengel constam da farmacopéia brasileira. Dentre as Mikanias Willdenow conhecidas por guaco merecem atenção as pertencentes a secção Globasae Robinson pelos usos que possuem na medicina popular e oficial. Este trabalho objetiva caracterizar microscopicamente as espécies brasileiras do gênero Mikania Willdenow Secção Globasae Robinson fornecendo subsídios a diagnose das drogas obtidas. Desenhos acompanham as descrições microscópicas e a chave artificial para a separação das espécies. A presença ou ausência nas folhas de camada celular aclorofilada subepidérmica separa as espécies da seção em 2 grupos de 4 espécies: 1) com característica: Mikania confertissima; M. laevigata; M. glomerata e M. hatschbachii; 2) sem característica: Mikania congesta; M. microlepsis; M. hookeriana; M. smilacina. Constitui características importantes na separação das espécies: número de camadas celulares do parênquima policádico; presença de braquiescléritos nas regiões parenquimática adjacente a feixes vasculares mais calibrosos; espessamento de paredes de células epidérmicas; presença de cutícula estriada; tipos de tricomas e de estomatos.