76 research outputs found

    Integrating Research and Education with Public Outreach at Coastal Laboratories

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    Coastal marine and Great Lakes laboratories increasingly are asked to provide both advisory and educational outreach to the general (and often specific) public. To facilitate this interchange, basic and applied research must be more integrated with advisory services, with care taken to present facts and concepts, not opinions or advocacy. Moreover, outreach efforts should be proactive, not reactive. With the rapid expansion of telecommunications, such as electronic mail and teleconferencing, outreach can optimize the links between education and research. Public outreach also gives graduate students an opportunity to utilize practical applications and interpretations of marine science, thus providing valuable experience that can help in obtaining future jobs. More problematic is how outreach activities can be evaluated in an annual or promotion review of a faculty member; particular care must be taken not confuse outreach with scholarship, or sacrifice intellectual rigor, in such evaluations

    Geological and Geophysical Character of the East China and Yellow Seas

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    The East China and Yellow seas represent one of the broadest shallow seas in the global ocean, with water depths generally less than 80 m and stretching nearly 750 km from the Shandong Peninsula to the Okinawa Trough (Fig. 1). This area is also unique in terms of the vast amount of sediment it receives from the Huanghe (Yellow River; presently discharging in the adjacent Gulf of Bohai) and the Changjigang (Yangtze River, which flows into the East China Sea). Together, this region receives about ten percent of the river-derived sediment reaching the ocean, and as such, the region has unique geological and oceanographic conditions that reflect both the present highstand of sea level as well as previous lowstands. The purpose of this report is to present and discuss the nature of the seafloor as well as the shallow structure of the surficial (Neogene) strata in the YS-ECS. The maps accompanying this report are the products of the analysis and interpretation of many types of seismic reflection data as well as many previously published papers dealing with this area. Specifically, we have utilized 3.5 kHz echo-soundings, various types of shallow-towed boomer profiles, sparker, air-gun and water-gun data as well as multichannel deep seismic data obtained by the former Gulf Oil Company. Moreover, we have integrated seismic refraction data gathered in the 1960\u27s and 1970\u27s (Fig. 2) in an attempt to gain better knowledge about the acoustic and (thereby) geological character of the deeper Neogene strata

    Water and Sediment Discharge from Small Mountainous Rivers, Taiwan: The Roles of Lithology, Episodic Events, and Human Activities

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    Taiwan’s natural setting creates highly vulnerable watersheds whose rivers discharge disproportionately large quantities of sediment to the coastal ocean. The 16 Taiwanese rivers analyzed in this article discharge ∌180 Mt yr-1 of sediment to the coastal ocean, although totals over the past 20 years have varied between 16 and 440 Mt yr-1. The mean annual sediment yield of 9500 t km-2 yr-1 for the 16 rivers is 60-fold greater than the global yield of 150 t km-2 yr-1, but mean yields for the individual rivers vary by more than 2 orders of magnitude, from 500 to 71,000 t km-2 yr-1. Most sediment erosion and delivery occur in response to typhoon-generated floods, as evidenced by the fact that \u3e75% of the long-term flux occurs in \u3c 1% of the time, about one-third of which reaches hyperpycnal concentrations. Detailed analysis of the 16 watersheds reveals little evidence of any single environmental factor that controls sediment load. The Erren, the highest-yield river on Taiwan, drains an erodible but low-gradient watershed with relatively low runoff. In contrast, three east coast rivers, the Hoping, the Hualien, and the Beinan, have high sediment yields that may be explained by relatively frequent earthquakes coupled with high runoff. Farming and urbanization also have elevated sediment yields in eastern watersheds, whereas Holocene sediments buried in the Taiwan Strait suggest that present-day sediment loads of the western rivers may be no higher than prehuman levels

    Geology, Geography, and Humans Battle for Dominance over the Delivery of Fluvial Sediment to the Coastal Ocean

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    Sediment flux to the coastal zone is conditioned by geomorphic and tectonic influences (basin area and relief), geography (temperature, runoff), geology (lithology, ice cover), and human activities (reservoir trapping, soil erosion). A new model, termed “BQART” in recognition of those factors, accounts for these varied influences. When applied to a database of 488 rivers, the BQART model showed no ensemble over‐ or underprediction, had a bias of just 3% across six orders of magnitude in observational values, and accounted for 96% of the between‐river variation in the long‐term (±30 years) sediment load or yield of these rivers. The geographical range of the 488 rivers covers 63% of the global land surface and is highly representative of global geology, climate, and socioeconomic conditions. Based strictly on geological parameters (basin area, relief, lithology, ice erosion), 65% of the between‐river sediment load is explained. Climatic factors (precipitation and temperature) account for an additional 14% of the variability in global patterns in load. Anthropogenic factors account for an additional 16% of the between‐river loads, although with ever more dams being constructed or decommissioned and socioeconomic conditions and infrastructure in flux, this contribution is temporally variable. The glacial factor currently contributes only 1% of the signal represented by our globally distributed database, but it would be much more important during and just after major glaciations. The BQART model makes possible the quantification of the influencing factors (e.g., climate, basin area, ice cover) within individual basins, to better interpret the terrestrial signal in marine sedimentary records. The BQART model predicts the long‐term flux of sediment delivered by rivers; it does not predict the episodicity (e.g., typhoons, earthquakes) of this delivery

    Calcium Carbonate Sedimentation in the Global Ocean: Linkages Between the Neritic and Pelagic Environments

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    Other than fluvial sediment, calcium carbonate (CaCO3) is the greatest source of sediment in the present-day ocean. Interest in carbonate sedimentation extends beyond geologists because the carbonate system involves biologic and geochemicalprocesses. Carbonate production, for example, releases CO2 but its accumulation becomes a major sink for inorganic carbon. Unlike fluvial sediments, modern carbonates accumulate more or less equally in the neritic and pelagic environments. Neritic carbonates (benthic) are characterized by rapid production of (mostly) metastable aragonite and magnesian calcite:pelagic production of (primarily) calcite in the open ocean occurs at much slower rates but overmuch larger areas than does neritic production (Table 1). A global understanding of the production, preservation, and accumulation of calcium carbonate thus necessitates understanding both theneritic and pelagic systems, even though communication between researchers in the two subdisciplines often has been minimal

    Hyperpycnal Discharge of Fluvial Sediment to the Ocean: Impact of Super‐Typhoon Herb (1996) on Taiwanese Rivers

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    Hyperpycnal events (when suspended sediment concentrations exceed 40 g/L) occur in small‐ and medium‐sized rivers throughout the world but are particularly common in Taiwan; they are often related to landslides or debris flows initiated and transported by typhoon floods. Super‐Typhoon Herb, which swept across Taiwan on July 31–August 2, 1996, triggered floods and landslides throughout the southern part of the island. Sediment concentrations in at least seven rivers (Taan, Choshui, Pachang, Erhjen, Tsengwen, Kaoping, and Peinan) approached or exceeded 40 g/L. Calculated sediment discharged from nine rivers (these seven as well as the Wu and Houlung, neither of which apparently reached hyperpycnal concentrations) during these 3 d was 217 million tons (MT)—most of it on August 1—of which ∌80% was discharged at hyperpycnal concentrations. Presumably, most of the sediments discharged by the Peinan River (to the southeast) and the Kaoping, Erhjen, Tsengwen, and Pachang rivers (to the southwest) were transported directly to the Huatong Basin and the South China Sea (via the Penghu Canyon system), respectively. The bulk of the typhoon‐derived sediment (142 MT), however, was discharged to the northwest (primarily by the Choshui River), and its fate remains unknown. It may have ultimately reached the Penghu Canyon system and thereby the South China Sea, but more probably it was transported northward (via the Taiwan Warm Current) toward China, the East China Sea, or (perhaps) the Okinawa Trough

    Sediments of the East Atlantic continental margin : a preliminary report

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    The location of sediment samples from the northern and equatorial portions of the western African continental shelf and upper slope are presented, along with a discussion of analytical techniques and some preliminary results.Supported by the National Science Foundation under Grant No. GX-28193

    Extraordinary human energy consumption and resultant geological impacts beginning around 1950CE initiated the proposed Anthropocene Epoch

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    Growth in fundamental drivers—energy use, economic productivity and population—can provide quantitative indications of the proposed boundary between the Holocene Epoch and the Anthropocene. Human energy expenditure in the Anthropocene, ~22 zetajoules (ZJ),exceeds that across the prior 11,700 years of the Holocene (~14.6 ZJ), largely through combustion of fossil fuels. The global warming effect during the Anthropocene is more thanan order of magnitude greater still. Global human population, their productivity and energy consumption, and most changes impacting the global environment, are highly correlated. This extraordinary outburst of consumption and productivity demonstrates how the Earth System has departed from its Holocene state since ~1950 CE, forcing abrupt physical, chemical and biological changes to the Earth’s stratigraphic record that can be used to justify the proposal for naming a new epoch—the Anthropocene

    Depositional patterns of modem Orinoco/Amazon muds on the northern Venezuelan shelf

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    Modern muds derived from the Orinoco and Amazon Rivers are gradually covering early Holocene (shallow-water) reefs and sands on the continental shelf and upper slope north of the Paria peninsula. Throughout much of the area the muds are more or less continuous and locally as thick as 20 m...
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