Systematic Variation of Sr-, Nd- and Pb-Isotopes with Time in Lavas of Mauritius, Reunion Hotspot     

NOHDA  SUSUMU; KANEOKA  ICHIRO; HANYU  TAKESHI; XU  SHENG; UTO  KOZO 《Journal of Petrology》2005,46(3):505-522

We report Sr-, Nd- and Pb-isotopic compositions for the lavasof Mauritius, the second youngest volcanic island in the Réunionhotspot. The lavas of the Older Series (7·8–5·5Ma) have identical isotopic compositions (⁸⁷Sr/⁸⁶Sr = 0·70411to 0·70422,¹⁴³Nd/¹⁴⁴Nd = 0·512865 to 0·512854,and ²⁰⁶Pb/²⁰⁴Pb = 19·016 to 19·041) to those ofRéunion, where the center of volcanic activity is currentlylocated. The lavas of the Intermediate Series (3·5–1·9Ma) and Younger Series (0·70–0·17 Ma) areshifted to lower Sr-isotopic compositions (0·70364–0·70394,with ¹⁴³Nd/¹⁴⁴Nd = 0·512813 to 0·512948 and ²⁰⁶Pb/²⁰⁴Pb= 18·794 to 18·984). The Intermediate Series lavashave similar trace-element characteristics (e.g. Zr–Nb,Ba–Y) to those of Rodrigues, in both cases requiring theinvolvement of an enriched mantle-like component in the mantlesource. During the volcanic history of Mauritius, the magmaslost the principal isotopic characteristics of the Réunionhotspot with time, and became gradually imprinted with the isotopicsignature of a shallower mantle source that produced the CentralIndian Ridge basalts. KEY WORDS: hotspot; isotopes; Mauritius; Réunion; trace element  相似文献   

Protection of marine birds and turtles at St Brandon’s Rock,Indian Ocean,requires conservation of the entire atoll     

SW Evans  N Cole  H Kylin  NS Choong Kwet Yive  V Tatayah  J Merven 《African Journal of Marine Science》2016,38(3):317-327

A survey of seabirds and turtles at St Brandon’s Rock, 400 km north of Mauritius, was undertaken in 2010. We estimated that 1 084 191 seabirds comprising seven breeding species and excluding non-breeders were present at the archipelago and we counted 279 turtle tracks and nesting pits of green turtles Chelonia mydas. Hawksbill turtles Eretmochelys imbricata were also present. Analyses of 30 different islets that make up the atoll showed that the seabird species mostly partitioned their use of islets based on islet size, with four species preferring larger islets and two species preferring smaller islets. Alien species introduced historically are still present and other threats, such as shipwrecks, remain. We propose conservation and other measures that should adequately protect the birds, turtles and coral reef by treating the atoll as a system.  相似文献   

Mauritius since the last glacial: environmental and climatic reconstruction of the last 38 000 years from Kanaka Crater     

Geert W. Van Der Plas  Erik J. De Boer  Henry Hooghiemstra  F. B. Vincent Florens  Claudia Baider  Johannes Van Der Plicht 《第四纪科学杂志》2012,27(2):159-168

A 10 m long peat core from the Kanaka Crater (20° 25′ S, 57° 31′ E), located at 560 m elevation in Mauritius, was analyzed for microfossils. Eight radiocarbon ages show the pollen record reflects environmental and climatic change of the last ca. 38 cal ka BP. The record shows that the island was continuously covered by forest with Erica heath (Philippia) in the uplands. Cyperaceous reedswamp with Pandanus trees was abundant in the coastal lowlands as well as locally in the waterlogged crater. The record shows changes in climatic humidity (wet from 38.0 to 22.7 cal ka BP, drier from 22.7 to 10.6 cal ka BP, and wetter again from 10.6 cal ka BP to recent) as the main response to climate change. A high turnover in montane forest species is evidenced at 22.7 cal ka BP and at the start of the Holocene. The limited altitudinal ranges in the mountains of Mauritius (maximum altitude 828 m), and changing humidity being more important than changing temperature, suggests that in response to climate change a reassortment in taxonomic composition of montane forests might be equally important as displacement of forest types to new altitudinal intervals. We found weak impact of the latitudinal migration of the Intertropical Convergence Zone and data suggest that the Indian Ocean Dipole is a more important driver for climatic change in the southwest Indian Ocean. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Sexism in the postcolonial society of Mauritius: The role of metropolisation and communalism     

《Applied geography (Sevenoaks, England)》2017

Sexism as a variety of prejudice is widely addressed as a severe social problem for society owing to its quality of establishing various forms of inequality. However, sexism is a rather neglected issue in geography especially concerning the global South. The postcolonial island state of Mauritius, agrarian-oriented and socially conservative but well integrated in global value chains, shows the unique combination of a strong paternalistic form of inward ethnic orientation, characteristic for most postcolonial states, combined with a minor tendency for metropolisation, which makes the island state worthwhile for the further development of generic theories of sexism in general. The paper analyses relevant predictors of sexism in Mauritius that can be useful in informing approaches that focus especially north/south differences of gender inequality. It becomes apparent that mechanisms of sexism in Mauritius are in most dimensions the same as the mechanisms found in the global North. Communalism and absent metropolisation remain significant, yet other important predictors are sex, life satisfaction, withholding citizen rights to foreign wives of Mauritian men, and xenophobic attitudes. These results point in the direction of the necessity to think in new ways about attitudinal differences of societies in the global North/South especially in postcolonial contexts.  相似文献   

Submarine groundwater springs are characterized by distinct fish communities     

Timo Pisternick  Julian Lilkendey  Anishta Audit-Manna  Danishta Dumur Neelayya  Yashvin Neehaul  Nils Moosdorf 《Marine Ecology》2020,41(5):e12610

The inflow of terrestrial groundwater into the ocean is increasingly recognized as an important local source of nutrients and pollutants to coastal ecosystems. Although there is evidence of a link between fresh submarine groundwater discharge (SGD)-derived nutrients and primary producer and primary consumer abundances, the effects of fresh SGD on the productivity of higher trophic levels such as ichthyofaunal communities remain unclear. To further investigate this relationship, we sampled three sites inside a coral reef lagoon in Mauritius: One site entailing six distinct groundwater springs, a site highly influenced by freshwater influx through the springs, and a strictly marine control site. Using remote underwater video surveys, we found that fish abundances were significantly higher at the groundwater springs than at the other two sampling sites.Principal component analyses showed that the springs and the spring-influenced part of the lagoon were best described by elevated water nutrient loadings, whereas the control site was characterized by higher water salinity and pH. Macroalgae cover was highest at the control site and the springs. Herbivores and invertivores dominated the fish community at the springs, in contrast to generalists at the control site. At the spring-influenced site, we mainly encountered high coral/turf algae cover and high abundances of associated fish feeding groups (territorial farmers, corallivores). Our results provide evidence of a fresh SGD-driven relationship between altered hydrography and distinct fish communities with elevated abundances at groundwater springs in a coral reef lagoon. These findings suggest that the management and assessment of secondary consumer productivity in tropical lagoons should take into account the effects of groundwater springs.  相似文献   

‘They are stealing my island’: Residents’ opinions on foreign investment in the residential tourism industry in Tamarin,Mauritius          下载免费PDF全文

Tessa Wortman  Ronnie Donaldson  Guus van Westen 《Singapore journal of tropical geography》2016,37(2):139-157

The small nation of Mauritius in the Indian Ocean, once a poor sugar plantation island, has successfully diversified and expanded its economy since independence, by attracting foreign investment in manufacturing and modern service industries. Tourism is a major part of the ‘Mauritian Miracle’; in recent years residential tourism—attracting wealthy foreigners to take up semi‐permanent residence—has become a growth industry transforming coastal areas like Tamarin. Based on in‐depth interviews among 17 residents of Tamarin, this paper looks at how local people perceive the changes residential tourism is causing in the local area. It appears that while the majority is positive about economic changes like more jobs and income opportunities, and to some extent about improvements in infrastructure and services, there are growing misgivings about some of the social impacts. Notably, the increasing scarcity of land and rising house prices are making it impossible for growing numbers of local people to afford a place to live, resulting in growing squatter settlements in the area. Such growing social disparities challenge the Mauritian development model and may undermine its stability. These undesirable effects call for careful management of tourism development, incorporation of sustainability standards and attention to the position of major stakeholder groups, such as local residents.  相似文献   

Intra-event characteristics of extreme erosive rainfall on Mauritius     

Werner Nel  Alexia Hauptfleisch  Paul D. Sumner  Ravindra Boojhawon  Soonil D. D. V. Rughooputh  Kumar R. Dhurmea 《自然地理学》2016,37(3-4):264-275

Mauritius is a volcanic island with a raised interior where extreme rainfall events dominate rainfall erosivity. Intra-event characteristics of the 120 highest erosive events at six selected locations between 2004 and 2008 were analyzed to provide the first detailed intra-storm data for a tropical island environment. On Mauritius, spatial variation is evident in the characteristics of extreme erosive rainfall recorded at the stations, with a noticeable increase in rainfall depth, duration, kinetic energy, and erosivity of extreme events with altitude. Extreme events in the raised interior (central plateau) show high variability of peak intensity over time as well as a higher percentage of events in which the greatest intensity occurs in the latter part of the event. Intra-event distribution of rainfall in the interior of the island shows that rainfall there has a higher potential to exceed infiltration rates as well as the ability to generate high peak runoff rates and cause substantial soil loss. The study suggests that even though within-event rainfall characteristics are complex, they have implications for soil erosion risk, and that, in tropical island environments, the within-storm distribution of rainfall should be incorporated in soil-loss modeling.  相似文献   

Beta diversity of pelagic assemblages at fish aggregating devices in the open ocean     

F Forget  L Dagorn  B Mérigot  JC Gaertner  J Robinson  PD Cowley 《African Journal of Marine Science》2020,42(2):247-254

Owing to difficulties in accessing the vast open ocean, the beta (β) diversity of pelagic fish assemblages remains poorly studied. We investigated the relationship between assemblage similarity and geographical distance between anchored fish aggregating devices (FADs), sampled by standardised underwater visual censuses in three anchored FAD arrays in the Indian Ocean—at the Maldives, the Seychelles and Mauritius. The use of two complementary indices of β-diversity, based on presence/absence data (Jaccard similarity coefficient) and abundance data (Bray–Curtis index), revealed that geographical distance between sampling sites (from 4 to 257 km) appeared to have no effect on the similarity of fish assemblages associated with FADs within each array. The results of this preliminary study question the generalisation of the paradigm of an increase in β-diversity with geographic distance to the open-ocean fish community. Large-scale studies using a variety of datasets should be conducted to further investigate patterns of β-diversity in the open ocean.  相似文献