Late Quaternary siliciclastic/carbonate sedimentation in the Cabricorn Channel

A model is presented for hemipelagic siliciclastic and carbonate sedimentation during the last glacial-interglacial cycle in the Capricorn Channel, southern Great Barrier Reef (GBR). Stable isotope ratios, grainsize, carbonate content and mineralogy were analysed for seven cores in a depth transect from 166 to 2892 m below sea level (mbsl). Results show variations in the flux of terrigenous, neritic and pelagic sediments to the continental slope over the last sea level cycle. During the glacial lowstand terrigenous sediment influenced all the cores down to 2000 mbsl. The percentages of quartz and feldspar in the cores decreased with water depth, while the percentage of clay increased. X-ray diffraction analysis of the glacial lowstand clay mineralogy suggests that the siliciclastic sediment was primarily sourced from the Fitzroy River, which debouched directly into the northwest sector of the Capricorn Channel at this time. The cores also show a decrease in pelagic calcite and an increase in aragonite and high magnesium calcite (HMC) during the glacial. The influx of HMC and aragonite is most likely from reworking of coral reefs exposed on the continental shelf during the glacial, and also from HMC ooids precipitated at the head of the Capricorn Channel at this time. Mass accumulation rates (MARs) are high (13.5 g/cm**/kyr) during the glacial and peak at ~20 g/cm** 3/kyr in the early transgression (16-14 ka BP). MARs then decline with further sea level rise as the Fitzroy River mouth retreats from the edge of the continental shelf after 13.5 ka BP. MARs remain low (4 g/cm**3/kyr) throughout the Holocene highstand. Data for the Holocene highstand indicate there is a reduction in siliciclastic influx to the Capricorn Channel with little quartz and feldspar below 350 mbsl. However, fine-grained fluvial sediments, presumably from the Fitzroy River, were still accumulating on the mid slope down to 2000 mbsl. The proportion of pelagic calcite in the core tops increases with water depth, while HMC decreases, and is present only in trace amounts in cores below 1500 mbsl. The difference in the percentage of HMC in the deeper cores between the glacial and Holocene may reflect differences in supply or deepening of the HMC lysocline during the glacial. Sediment accumulation rates also vary between cores in the Capricorn Channel and do not show the expected exponential decrease with depth. This may be due to intermediate or deep water currents reworking the sediments. It is also possible that present bathymetry data are too sparse to detect the potential role that submarine channels may play in the distribution and accumulation of sediments. Comparison of the Capricorn Channel MARs with those for other mixed carbonate/siliciclastic provinces from the northeast margin of Australia indicates that peak MARs in the early transgression in the Capricorn Channel precede those from the central GBR and south of Fraser Island. The difference in the timing of the carbonate and siliciclastic MAR peaks along the northeast margin is primarily related to differences in the physiography and climate of the provinces. The only common trend in the MARs from the northeast margin of Australia is the near synchronicity of the carbonate and siliciclastic MAR peaks in individual sediment cores, which supports a coeval sedimentation model.

Clustering of related individuals in a population of the Australian lizard, Egernia frerei

Stable social aggregations are rarely recorded in lizards, but have now been reported from several species in the Australian scincid genus Egernia. Most of those examples come from species using rock crevice refuges that are relatively easy to observe. But for many other Egernia species that occupy different habitats and are more secretive, it is hard to gather the observational data needed to deduce their social structure. Therefore, we used genotypes at six polymorphic microsatellite DNA loci of 229 individuals of Egernia frerei, trapped in 22 sampling sites over 3500 ha of eucalypt forest on Fraser Island, Australia. Each sampling site contained 15 trap locations in a 100 x 50 m grid. We estimated relatedness among pairs of individuals and found that relatedness was higher within than between sites. Relatedness of females within sites was higher than relatedness of males, and was higher than relatedness between males and females. Within sites we found that juvenile lizards were highly related to other juveniles and to adults trapped at the same location, or at adjacent locations, but relatedness decreased with increasing trap separation. We interpreted the results as suggesting high natal philopatry among juvenile lizards and adult females. This result is consistent with stable family group structure previously reported in rock dwelling Egernia species, and suggests that social behaviour in this genus is not habitat driven.

Management effectiveness: Assessing management of protected areas?

To maximise the potential of protected areas, we need to understand the strengths and weaknesses in their management and the threats and stresses that they face. There is increasing pressure on governments and other bodies responsible for protected areas to monitor their effectiveness. The reasons for assessing management effectiveness include the desire by managers to adapt and improve their management strategies, improve planning and priority setting and the increasing demands for reporting and accountability being placed on managers, both nationally and internationally. Despite these differing purposes for assessment, some common themes and information needs can be identified, allowing assessment systems to meet multiple uses. Protected-area management evaluation has a relatively short history. Over the past 20 years a number of systems have been proposed but few have been adopted by management agencies. In response to a recognition of the need for a globally applicable approach to this issue, the IUCN World Commission on Protected Areas developed a framework for assessing management effectiveness of both protected areas and protected area systems. This framework was launched at the World Conservation Congress in Jordan in 2000. The framework provides guidance to managers to develop locally relevant assessment systems while helping to harmonise assessment approaches around the world. The framework is strongly linked to the protected area management process and is adaptable to different types and circumstances of protected areas around the world. Examples from Fraser Island in Australia and the Congo Basin illustrate the use of the framework.

Effects of fire on the structure and composition of open eucalypt forests

Fires are integral to the healthy functioning of most ecosystems and are often poorly understood in policy and management, however, the relationship between floristic composition and habitat structure is intrinsically linked, particularly after fire. The aim of this study was to test whether the variability of habitat structure or floristic composition and abundance in forests at a regional scale can be explained in terms of fire frequency using historical data and experimental prescribed burns. We tested this hypothesis in open eucalypt forests of Fraser Island off the east coast of Australia. Fraser Island dunes show progressive stages in plant succession as access to nutrients decreases across the Island. We found that fire frequency was not a good predictor of floristic composition or abundance across dune systems; rather, its affects were dune specific. In contrast, habitat structure was strongly influenced by fire frequency, independent of dune system. A dense understorey occurred in frequently burnt areas, whereas infrequently burnt areas had a more even distribution of plant heights. Plant communities returned to pre-burn levels of composition and abundances within 6 months of a fire and frequently burnt areas were dominated by early successional species of plant. These ecosystems were characterized by low diversity and frequently burnt areas on the east coast were dominated by Pteridium. Greater midstorey canopy cover in low frequency areas reduces light penetration and allows other species to compete more effectively with Pteridium. Our results strongly indicate that frequent fires on the Island have resulted in a decrease in relative diversity through dominance of several species. Prescribed fire represents a powerful management tool to shape habitat structure and complexity of Fraser Island forests.

Drifting blooms of the endemic filamentous brown alga Hincksia sordida at Noosa on the subtropical east Australian coast

Since 2002, the usually uncommon endemic filamentous brown alga Hincksia sordida (Harvey) Silva (Ectocarpales, Phaeophyta) has formed nuisance blooms annually during spring/early summer at Main Beach, Noosa on the subtropical east Australian coast. The Hincksia bloom coincides with the normally intensive recreational use of the popular bathing beach by the local population and tourists. The alga forms dense accumulations in the surf zone at Main Beach, giving the seawater a distinct brown coloration and deterring swimmers from entering the water. Decomposing algae stranded by receding tides emit a nauseating sulphurous stench which hangs over the beach. The stranded algal biomass is removed from the beach by bulldozers. During blooms, the usually crowded Main Beach is deserted, bathers preferring to use the many unaffected beaches on the Sunshine Coast to the south of Main Beach. The bloom worsens with north-easterly winds and is cleared from Noosa by south easterly winds, observations which have prompted the untenable proposal by local authorities that the bloom is forming offshore of Fraser Island in the South Pacific Ocean. The Noosa River estuarine system/Laguna Bay is the more probable source of the bloom and the nutrient inputs into this system must be substantial to generate the high bloom biomass. Current mitigation procedures of removing the blooming alga off the beach with bulldozers treat the symptom, not the cause and are proving ineffective. Environmental management must be based on science and the Noosa bloom would benefit greatly from the accurate ecological data on which to base management options. (c) 2006 Elsevier Ltd. All rights reserved.

Historical record of polycyclic aromatic hydrocarbons (PAHs) and spheroidal carbonaceous particles (SCPs) in marine sediment cores from Admiralty Bay, King George Island, Antarctica

This paper describes the first results of polycyclic aromatic hydrocarbons (PAHs) and spheroidal carbonaceous particles (SCPs) in sediment cores of Admiralty Bay, Antarctica. These markers were used to assess the local input of anthropogenic materials (particulate and organic compounds) as a result of the influence of human occupation in a sub-Antarctic region and a possible long-range atmospheric transport of combustion products from sources in South America. The highest SCPs and PAHs concentrations were observed during the last 30 years, when three research stations were built in the area and industrial activities in South America increased. The concentrations of SCPs and PAHs were much lower than those of other regions in the northern hemisphere and other reported data for the southern hemisphere. The PAH isomer ratios showed that the major sources of PAHs are fossil fuels/petroleum, biomass combustion and sewage contribution generally close to the Brazilian scientific station. (C) 2009 Elsevier Ltd. All rights reserved.

Kelp gulls, Larus dominicanus (Aves: Laridae), breeding in Keller Peninsula, King George Island, Antarctic Peninsula

We examined the distribution, abundance and density of the Kelp Gull, Larus dominicanus (Lichtenstein, 1823), at Keller Peninsula on two occasions during the breeding season of 2007-2008 (once for incubation and once for chick stages) and compared our results with previously published data. We present information on the number of eggs, incubation success, and initial development of L. dominicanus chicks in the studied sites. The abundance and density of the species has remained statistically similar in Keller Peninsula over the last 30 years (since 1978-1979). Although the abundance and density were almost unchanged, we recorded alterations in the occupation of the breeding areas by L. dominicanus, mainly the abandonment of breeding sites in the eastern portion of Keller Peninsula. The results of the present study compared with similar previous investigations on the abundance of L. dominicanus indicate that the populations have been in equilibrium over the years.

Heavy metal concentrations in soils from a remote oceanic island, Fernando de Noronha, Brazil

This paper examines the role of parent rock, pedogenetic processes and airborne pollution in heavy metal accumulation in soils from a remote oceanic island, Fernando de Noronha, Brazil. We studied five soil profiles developed from different volcanic rocks. Mineralogical composition and total concentrations of major and trace elements were determined in 43 samples. The obtained concentrations range for heavy metals were: Co: 26-261 ppm; Cu: 35-97 ppm; Cr: 350-1446 ppm; Ni: 114-691 ppm; Zn: 101-374 ppm; Hg: 2-150 ppb. The composition of soils is strongly affected by the geochemical character of the parent rock. Pedogenesis appears to be responsible for the accumulation of Zn, Co, and, to a lesser extent, of Ni and Cu, in the upper, Mn- and organic carbon-enriched horizons of the soil profiles. Pedogenic influence may also explain the relationship observed between Cr and the Fe. Hg is likely to have been added to the soil profile by long-range atmospheric transport. Its accumulation in the topsoil was further favoured by the formation of stable complexes with organic matter. Clay minerals do not appear to play an important role in the fixation of heavy metals.

Late Quaternary drainage dynamics in northern Brazil based on the study of a large paleochannel from southwestern Marajó Island

Marajó Island shows an abundance of paleochannels easily mapped in its eastern portion, where vegetation consists mostly of savannas. SRTM data make possible to recognize paleochannels also in western Marajó, even considering the dense forest cover. A well preserved paleodrainage network from the adjacency of the town of Breves (southwestern Marajó Island) was investigated in this work combining remote sensing and sedimentological studies. The palimpsest drainage system consists of a large meander connected to narrower tributaries. Sedimentological studies revealed mostly sharp-based, fining upward sands for the channelized features, and interbedded muds and sands for floodplain areas. The sedimentary structures and facies successions are in perfect agreement with deposition in channelized and floodplain environments, as suggested by remote sensing mapping. The present study shows that this paleodrainage was abandoned during Late Pleistocene, slightly earlier than the Holocene paleochannel systems from the east part of the island. Integration of previous studies with the data available herein supports a tectonic origin, related to the opening of the Pará River along fault lineaments. This would explain the disappearance of large, north to northeastward migrating channel systems in southwestern Marajó Island, which were replaced by the much narrower, south to southeastward flowing modern channels.

Contraceptive use and associated factors among adolescents on Santiago Island - Cape Verde - Western Africa

OBJECTIVE: to estimate the prevalence of contraceptive use and associated factors among adolescents attending public schools on Santiago Island, Cape Verde. METHODS: a cross-sectional study was carried out with 368 sexually active adolescents aged 13-17years attending eight public elementary and high schools, randomly selected, on Santiago Island, Cape Verde, between January and March 2007. Poisson regression with robust variance was used for the multiple analysis of risk factors, at a 5% level of significance. RESULTS: among 368 adolescents, 69.3% reported having used a contraceptive method during the last act of sexual intercourse. The most frequently used method were condom (94.9%) and pill (26.4%). Factors significantly and positively associated with contraceptive use were: living in the capital (PR=1.23; CI95%: 1.07; 1.39); having dated and had sexual intercourse (PR =1.53; CI95%: 1.14;2.06); and having more than nine years of schooling (PR=1.19; CI95%: 1.02; 1.38). CONCLUSIONS: more educated adolescents who studied in Praia (the capital city) and were dating at the time of the study were more likely to use contraception. The high prevalence of condom use and the association between contraception use and years of schooling among adolescents may indicate that sexual and reproductive health policies have produced positive outcomes that may account for the decrease in HIV infection.

Factors associated with sexual initiation and condom use among adolescents on Santiago Island, Cape Verde, West Africa

Foram analisados fatores associados ao início da vida sexual de adolescentes na Ilha de Santiago, Cabo Verde, segundo sexo. Estudo realizado com amostra probabilística e representativa de 768 adolescentes, age 13-17 anos, de escolas secundárias públicas da Ilha de Santiago em 2007. A associação foi testada pelo teste de proporção, qui-quadrado de Pearson ou Fisher e regressão logística. Nos rapazes, os fatores associados ao início da vida sexual foram: idade maior que 14 anos, ser católico e consumo de bebidas alcoólicas. Para meninas: escolaridade maior que nove anos e ter parceiro afetivo-sexual. Ao contrário de outros contextos da África Subsaariana, foram constatadas taxas elevadas de uso de preservativo por adolescentes no início da vida sexual. Os adolescentes podem iniciar a vida sexual de maneira mais segura se tiverem informação, educação sexual e acesso a métodos de prevenção à gravidez e às DST. Este artigo oferece elementos para a reflexão sobre o delineamento de políticas de redução da vulnerabilidade dos jovens às DST/AIDS e sobre os limites e desafios da promoção do uso do preservativo e educação sexual, focando as relações desiguais de gênero

Quaternary paleoenvironments and relative sea-level changes in Marajo Island (Northern Brazil): Facies, delta(13)C, delta(15)N and C/N

The reconstruction of physical environments of Amazonian areas is of great interest to determine the dynamic evolution of the Amazon drainage basin. However. few studies have emphasized the Quaternary deposits in this region. which is mostly due to the lack of natural exposures imposed by the low topography. This work integrates facies analysis. radiocarbon dating, delta(13)C, delta(15)N, and C/N of an 124 m-thick core from an area located at the mouth of the Amazon River. northeastern Amazonia. The study records deposits up to 50.795 (14)C yr B P. in age. which formed in a variety of depositional environments including fluvial channel, tidal flat, outer estuarine basin to shallow marine. inner estuarine basin, estuarine channel and lagoon. Facies interpretation was significantly improved with the inclusion of delta(13)C, delta(15)N, and C/N analyses of organic matter extracted from the sediments The obtained values conform to a transitional. mostly estuarine paleosetting evolved during successive relative sea-level fluctuations. The results suggest fluvial deposition between 40,950 (+/- 590) and 50.795 (14)C yr B P, with a rise in relative sea level that commenced between 35,567 (+/- 649) and 39,079 (+/- 1114) (14)C yr B P. An overall transgression took place until 29,340 (+/- 340) (14)C yr B P., after which the relative sea level dropped, favoring valley rejuvenation and incision. Following this time up to 10,479 (+/- 34) (14)C yr B.P. a rise in relative sea level filled up the valley with estuarine deposits After 10.479(+/- 34) (14)C yr B.P., the estuary was replaced by a lagoon At the end of the Holocene, the coastline prograided approximately 45 km northward, replaci ng the lagoon by a lake system Despite the influence of eustatic fluctuations. regional tectonics played a significant role to create new space where these Late Pleistocene and Holocene sediments accumulated. (C) 2009 Elsevier B V All rights reserved.