Climatically induced lake level changes during the last two millennia as reflected in sediments of Laguna Potrok Aike,southern Patagonia (Santa Cruz,Argentina)

The volcanogenic lake Laguna Potrok Aike, Santa Cruz, Argentina, reveals an unprecedented continuous high resolution climatic record for the steppe regions of southern Patagonia. With the applied multi-proxy approach rapid climatic changes before the turn of the first millennium were detected followed by medieval droughts which are intersected by moist and/or cold periods of varying durations and intensities. The total inorganic carbon content was identified as a sensitive lake level indicator. This proxy suggests that during the late Middle Ages (ca. AD 1230–1410) the lake level was rather low representing a signal of the Medieval Climate Anomaly in southeastern Patagonia. At the beginning of the Little Ice Age the lake level rose considerably staying on a high level during the whole period. Subsequently, the lake level lowered again in the course of the 20th century.     

BOOK REVIEWS

Book Reviewed in this article: Geography and the Third World. International Seminar, 14–18 May 1980, Kuala Lumpur, Malaysia . Ishmail Ahmad and Jamaluddin Md Jahi, eds. The Growth Dilemma: Residents' Views and Local Population Change in the United States . Mark Baldassare. Sport and Place: A Geography of Sport in England, Scotland & Wales . John Bale. The Deindustrialization of America: Plant Closings, Community Abandonment, and the Dismantling of Basic Industry . Barry Bluestone and Bennett Harrison. Selected Essays 1963–1975: Carl O. Sauer . Bob Callahen, ed. Housing and Planning in the Countryside . G. Clark. Conflict, Politics and the Urban Scene . Kevin R. Cox and R. J. Johnston, eds. Thematic Maps: Their Design and Production . David J. Cuff and Mark T. Mattson. Wine: A Geographic Appreciation . Harm Jan de Blij. USSR in Maps . J. C. Dewdney. Political Geography: A Contemporary Perspective . Ramesh D. Dikshit. Rethinking Human Adaptation . Rada Dyson-Hudson and Michael A. Little, eds. Sacred Sands: The Struggle for Community in the indiana Dunes . J. Ronald Engel. Geography of the Biosphere . A. Furley and Walter W. Newey. Disaster and Reconstruction . Robert Geipel. Glasgow: The Making of a City . Andrew Gibb. Design for Arid Regions . Giden S. Golany, ed. Urbanization and Cancer Mortality: The United States Experience, 1950–1975 . Michael R. Greenberg. Geology in the Nineteenth Century: Changing Views of a Changing World . Mott T. Greene. Colonización y Destrucción de Bosques en Panamá . Stanley Heckadon Moreno and Alberto McKay, eds. Urban Geography: A First Approach . David T. Herbert and Colin J. Thomas. The Visual and Spatial Structure of Landscapes . Tadahiko Higuchi. Climate from Tree Rings . M. K. Hughes, P. M. Kelly, J. R. Pilcher, and V. C. LaMarche, Jr., eds. The structure of Nineteenth Century Cities . James H. Johnson and Colin G. Pooley, eds. The American Planner: Biographies and Recollections . Donald A. Krueckeberg, ed. Urban Land Policy For the 1980s, the Message for State and Local Government . George Lefcoe, ed. Regional Planning: Evolution, Crisis and Prospects . Gill C. Lim, ed. Relevance and Ethics In Geography . Bruce Mitchell and Dianne Draper. China: The Geography of Development and Modernization . Clifton W. Pannell and Laurence J. C. MA. The Urban Retailing System . Robert B. Potter. Hants. Nonconventional Energy Resources . Philip R. Pryde. Caribbean Migrants: Environment and Human Survival on St. Kitts and Nevis . Bonham C. Richardson. Population and Resources . Harry Robinson. East Los Angeles: History of A Barrio . Ricardo Romo. Integrated Impact Assessment . Frederick A. Rossini and Alan L. Porter, eds. Environmental Aesthetics: Essays in Interpretation . Barry Sadler and Allen Carlson, eds. Earthwatch . Charles Sheffield. Field Techniques and Research Methods in Geography . Robert H. Stoddard. Haiti: Land of Poverty . Robert J. Tata. Weathering and Erosion: Sources and Methods in Geography . Stephen T. Trudgill. Once Beneath the Forest. Prehistoric Terracing in the Río Bec Region of the Maya Lowlands . B. L. Turner, II. The Historical Geography of Scotland since 1707 . David Turnock.     

PLS RESPONSE SURFACE OPTIMIZATION:THE CARSO PROCEDURE

The paper presents a procedure to obtain response surfaces with non-designed data.The method is basedon PLS modelling of the expanded X-matrix followed by transformation of the PLS loadings intopolynomial coefficients and detection of the co-ordinates of the best response within the experimentaldomain.The results are presented both graphically and numerically.The procedure is validated on anoptimization study of the yield of an organic reaction.     

Response of the soft coral Heteroxenia fuscescens to ultraviolet radiation regimes as reflected by mycosporine-like amino acid biosynthesis

The variation in mycosporine‐like amino acid (MAA) concentration in the soft coral Heteroxenia fuscescens in relation to changes in ultraviolet radiation (UVR) regimes was investigated at the Gulf of Eilat, northern Red Sea. Solar radiation (300–700 nm) was measured for different depths and seasons. The UVR irradiance was measured to a depth of 25 m on the reef. The mean attenuation coefficient for UV‐B measured in winter was twofold that of the summer value. Separation of H. fuscescens extracts by reverse‐phase isocratic high‐performance liquid chromatography revealed a single MAA compound, palythine (λ_max = 320 nm). Possible seasonal changes in MAAs in colonies of H. fuscescens along a depth gradient were examined on different dates. Palythine concentrations in the colonies were significantly higher in summer than in the other seasons particularly in shallow water. Possible changes in MAA content in colonies of H. fuscescens as a result of UVR protection, were determined by experiments conducted for periods of 1 week, 1 month and 3 months, at a depth of 5 m. In these experiments colonies were removed from the natural substrate and placed underwater, protected from UVR by a PVC filter. Significant differences between UV‐exposed and protected colonies of H. fuscescens were found only in the 3‐month experiment conducted during the summer. These findings demonstrate that UVR is an important environmental factor regulating MAA biosynthesis in the soft coral H. fuscescens.     

Probability models for offshore structural response due to Morison wave loading: Part II: Inertia-only and total responses

Offshore structures are exposed to random wave loading in the ocean environment and hence the probability distribution of their response to wave loading is a minimum requirement for efficient probabilistic analysis of these structures. Due to nonlinearity of Morison wave loading and also due to intermittency of wave loading on members in the splash zone, the response is often non-Gaussian. Part I of this paper was devoted to the development and validation of a new probability model for drag-only responses (i.e. responses due to the drag component of Morison wave loading). This part is devoted to the development and validation of new probability models for both inertia-only and total responses.     

云南中甸纳帕海湖泊记录指示的57ka环境演化

根据沉积环境，总有机碳，氢指数，有机碳同位素，磁化率和粒度等替代性指标以及和陆地，深海气候记录的对比，重建了纳帕海57kaBP以来的湖面变化和主要气候演化阶段，57-32kaBP主要为低湖面和频繁的湖面波动，与气候的暖偏干/凉偏湿交替有关。32-15kaBP湖面大幅度上升，出现相对高湖面，气温下降，有效湿度增加，全新世湖盆的萎缩与持续的暖偏干气候有关，这种冷湿-暖干气候与滇西北特殊的地形地貌造成大气环流的独特性有关。     

The influence of an extreme drought event in the fish community of a southern Europe temperate estuary

Between 2003 and 2006, a severe drought occurred throughout the Mondego River catchment's area, inducing lower freshwater flows into the estuary. As a consequence, both 2004 and 2005 were considered as extreme drought events. From June 2003 to June 2006, the fish assemblage of the Mondego Estuary was sampled monthly in five stations during the night, using a 2 m beam trawl. Fish abundance was standardized as the number of individuals per 1000 m² per season and the assemblage was analyzed based on ecological guilds: estuarine residents, marine juveniles, marine adventitious, freshwater, catadromous and marine species that use the estuary as a nursery area. A total of 42 species belonging to 23 families were identified, with estuarine residents and nursery species dominating the fish community. Variations in the fish community were assessed using non-metric MDS, being defined as three distinct periods: summer and autumn 2003, 2004/2005 and winter and summer 2006. The main drought-induced effects detected were the depletion of freshwater species and an increase in marine adventitious in 2004/2005, due to an extended intrusion of seawater inside the estuary and a significant reduction in abundance during the driest period of estuarine resident species. Nevertheless, from the management point of view, it could be stated that although some variations occurred due to environmental stress, the main core of the Mondego Estuary fish community remained relatively unchanged.     

闽南沿海前湖剖面及其第四纪地质若干问题

前湖剖面第四系出露比较完整，层次清晰，发育有炭质层、铁盘、重矿砂砾石层、“老红砂”层和玄武岩等特殊地层，是一个研究闽南沿海第四纪地质问题的比较有代表性的地表露头剖面。本文通过对前湖剖面中系列样品进行测年、微古、孢粉、矿物、粒度等综合分析研究，探讨了闽南沿海晚更新世晚期以来的古气候变化、海平面变动、“老红砂”的形成年代及成因以及第四纪地层划分等问题。     

Comparison of Phytoplankton Species Composition and Abundance in the Rias Arosa and Muros (NW Spain)

Abstract. Seasonal changes in phytoplankton species composition and abundance were studied in the Rias de Arosa and Muros (NW Spain) in November 1975, April and August 1976. Data on density and percentage contribution of species were used to calculate spatial and temporal relationships of phytoplankton communities by affinity matrices. The phytoplankton communities of both rias differed in species composition and abundance during the three sampling seasons. Diatoms dominated and total abundance was always higher in Arosa. Both rias have upwelling of nutrient-rich oceanic water but the Arosa has an intense raft aquaculture of the edible mussel Mytilus edulis.     

Wave-induced motions of an air cushion structure in shallow water

Model tests were conducted on two 1:100 scaled models of a typical concrete gravity substructure at the University of Western Australia. The two models had dimensions 0.5 m length×0.5 m width with the first model being a sealed closed bottom box of height 0.1 m and the second model being an open bottom box with skirt length of 0.1 m. The mass of the air cushion model was changed to accommodate various water plug heights within the skirt chamber. Each model was floated at a constant draft of 0.1 m and tested in water depths ranging between 0.03 m (shallow) and 0.8 m (deep). The environment comprised regular waves with periods ranging between 0.6 and 3.5 s and amplitude of 0.08–0.02 m. To quantify the dynamic response the heave and pitch motions of each model were measured.A simplified theoretical solution based on long wavelength, linear wave assumptions was developed and applied to the geometries in consideration. Improvements to the theory are sought using the forcing function from a boundary element code, as well as utilizing added mass coefficients from free decay experiments. Results show that experimental trends compare reasonably well with analytical solution in particular for periods longer than the natural period. The results show that introducing air cushion support into a CGS increases the pitch response, while having little effect of the heave motion.