Kinetic studies of lead(II) uptake by the seagrass Zostera muelleri in water by radiotracing,atomic absorption spectrometry and electrochemical techniques

Evidence was found that uptake of lead from seawater in both model and natural systems by the leaves of the seagrass Zostera muelleri does occur for live, dead and scraped leaves at all the lead concentrations tested. Positive uptake of lead was measured using the three analytical techniques of radio-tracer, differential pulse anodic stripping voltammetry and atomic absorption spectrometry; similar uptake profiles were obtained for each technique. Profiles always showed an initial rapid uptake phase followed by a gradual transition to a plateau phase at which an approximate equilibrium between lead attached to seagrass and free ionic lead in seawater was reached. The presence of active lead uptake processes was indicated in experiments which attempted to remove lead from leaves by a chelating agent.     

Building capacity for integrated coastal management in developing countries

The need for building human and institutional capacity has been identified in Agenda 21 of the UNCED conference as well as by a number of international environmental institutions as essential for integrated coastal management (ICM) and sustainable development in developing coastal states. There is a growing need for coastal management practitioners and organizations with expertise in planning and implementation for ICM. The application of strategies for institutional development and building human capacity in coastal management and other fields shows that short-term intensive training efforts and long-term institutional strengthening programs are appropriate to address the issues and needs of ICM. An overview of the experience of the URI/USAID International Coastal Resources Management Program in Sri Lanka, Thailand and Ecuador presents lessons learned for strengthening ICM efforts in developing countries.     

Current-influenced depositional provinces, continental margin off Cape Hatteras, identified by petrologic method

Analyses of DSRV “Alvin” core samples on the Cape Hatteras margin indicate major textural and compositional changes at depths of about 1000 and well below 2500 m. The distribution patterns of petrologic parameters correlate well with water mass flow and suspended-sediment plumes measured on this margin by other workers. Our study also shows: (a) vigorous erosion and sediment transport at depths of less than 400 m resulting from the NE-trending Gulf Stream flow; (b) deposition, largely planktonic-rich sediment released from the Gulf Stream, on the upper- to mid-slope, to depths of about 800–1200 m; (c) winnowing, resuspension and deposition induced by periodically intensified slope currents on the mid-slope to uppermost rise, between about 1000 and 2500 m; and (d) prevailing deposition on the upper rise proper (below 2500 m), from transport by the SW-trending Western Boundary Undercurrent. Sediments moved by bottom currents have altered the composition and distribution patterns of material transported downslope by offshelf spillover; this mixing of gravity-emplaced and bottom-current-transported sediment obscures depositional boundaries. Moreover, reworking of the seafloor by benthic organisms alters physical properties and changes erodability of surficial sediments by bottom currents. Measurement of current flow above the seafloor and direct observation of the bottom are insufficient to delineate surficial sediment boundaries. Detailed petrologic analyses are needed to recognize the long-term signature of processes and define depositional provinces.     

Temporal fluctuations in weather disasters: 1950–1989

A unique historical data set describing the 142 storms producing losses in excess of $100 million in the United States during the 1950–89 period were analyzed to describe their temporal characteristics. These weather disasters (WDs) caused $66.2 billion in losses, 76% of the nation's insured losses in this period. Disasters were most prevalent in the south, southeast, northeast, and central U.S., with few in and west of the Rockies. The incidence of WDs was high in the 1950s, low in the 1960s-early 1970s, and peaked in the 1980s. Losses due to WDs peaked in the 1950s, again in the late 1960s, and with a lesser peak after 1985. The areal extent of storm losses peaked after 1975 and was least in the 1960s. The temporal variations of the three storm measures (incidence, losses, and extent) had poor agreement, and agreed only when they peaked in the 1950s. Regionally-derived time distributions of WDs showed marked north-south differences with a U-shaped 40-year distribution in the northern half of the nation, whereas southern regions had a relatively flat trend until achieving a peak in the 1980s. The temporal distributions of hurricane-caused disasters differed regionally, with the distributions in the southern, southeastern, and northeastern U.S. each quite different. Temporal distributions of thunderstorm and winter storm-produced disasters were regionally more uniform. The national 5-year WD frequencies correlated moderately well with annual mean temperatures which explained 40% of the variability found in WDs during 1950–89. Weather disasters peaked in the relatively warm-dry 1950s and again in the warm-wet 1980s, and were least in the cool-wet 1960s and 1970s. The distribution of WDs during 1950–89 appears positively related to the temporal fluctuations in cyclonic activity.     

Variations on a Hebrew theme: The politics of art music in Israel

No culture, no society, remains static but changes imperceptibly day by day. The struggle waged by western art music in Israel for survival is eerily suggestive of how Israeli society in general has changed since the early Zionists set the course for the creation of a Jewish nation-state. Once regarded as the civilized face and civilizing influence of the Jewish national endeavour in Palestine/Israel, its advocates claim ever more desperately that western art music in Israel is in a state of rapid decline. Yet public opinion surveys reveal that the Israeli public backs state support for arts and culture whether or not people participate in cultural activities. Despite this, the internal ethnic struggle for domination of the arts and culture world and the rearguard action by culture administrators are both in danger of being overtaken by the country’s exposure to global popular culture.     

Chlorine-36 in groundwater of the United States: empirical data

Natural production of the radionuclide chlorine-36 (³⁶Cl) has provided a valuable tracer for groundwater studies. The nuclear industry, especially the testing of thermonuclear weapons, has also produced large amounts of ³⁶Cl that can be detected in many samples of groundwater. In order to be most useful in hydrologic studies, the natural production prior to 1952 should be distinguished from more recent artificial sources. The object of this study was to reconstruct the probable preanthropogenic levels of ³⁶Cl in groundwater in the United States. Although significant local variations exist, they are superimposed on a broad regional pattern of ³⁶Cl/Cl ratios in the United States. Owing to the influence of atmospherically transported ocean salt, natural ratios of ³⁶Cl/total Cl are lowest near the coast and increase to a maximum in the central Rocky Mountains of the United States. Electronic Publication     

Climate-Years in the True Prairie: Temporal Fluctuations of Ecologically Critical Climate Conditions

The True Prairie (TP) is a large area in the central U.S. which was a tall grass prairie for thousands of years prior to its conversion to crop land. An analysis of climatically controlling factors indicated that the tall grass prairie is favored by the ratio of warm season precipitation to potential evapotranspiration exceeding 0.75 (west boundary), cold season precipitation less than 38 cm (south boundary), high cold-season frequency of thunderstorms (north boundary), and high drought frequencies (entire region). A `climate-year' approach was used to assess the temporal and spatial variability of these conditions during the 20thcentury. This analysis did not reveal any long-term trends in most climate-year types, although there were significant decadal-scale fluctuations, most notably a high frequency of drought-type years in the 1930s and 1950s. However, the well-documented upward trend in precipitation is manifested in an increasing frequency of one climate-year type characterized by above normal cold season precipitation in the southern border area of the TP.