Hurricanes 2004: An overview of their characteristics and coastal change

Four hurricanes battered the state of Florida during 2004, the most affecting any state since Texas endured four in 1884. Each of the storms changed the coast differently. Average shoreline change within the right front quadrant of hurricane force winds varied from 1 m of shoreline advance to 20 m of retreat, whereas average sand volume change varied from 11 to 66 m³ m⁻¹ of net loss (erosion). These changes did not scale simply with hurricane intensity as described by the Saffir-Simpson Hurricane Scale. The strongest storm of the season, category 4 Hurricane Charley, had the least shoreline retreat. This was likely because of other factors like the storm's rapid forward speed and small size that generated a lower storm surge than expected. Two of the storms, Hurricanes Frances and Jeanne, affected nearly the same area on the Florida east coast just 3 wk apart. The first storm, Frances, although weaker than the second, caused greater shoreline retreat and sand volume erosion. As a consequence, Hurricane Frances may have stripped away protective beach and exposed dunes to direct wave attack during Jeanne, although there was significant dune erosion during both storms. The maximum shoreline change for all four hurricanes occurred during Ivan on the coasts of eastern Alabama and the Florida Panhandle. The net volume change across a barrier island within the Ivan impact zone approached zero because of massive overwash that approximately balanced erosion of the beach. These data from the 2004 hurricane season will prove useful in developing new ways to scale and predict coastal-change effects during hurricanes.     

Respiration and denitrification in permeable continental shelf deposits on the South Atlantic Bight: Rates of carbon and nitrogen cycling from sediment column experiments

Nitrogen (N) cycling and respiration rates were measured in sediment columns packed with southeastern United States continental shelf sands, with high permeability (4.66×10⁻¹¹ m²) and low organic carbon (0.05%) and nitrogen (0.008%). To simulate porewater advection, natural shelf seawater was pumped through columns of different lengths to achieve fluid residence times of approximately 3, 6, and 12 h. Experiments were conducted seasonally at in situ temperature. Fluid flow was uniform in nearly all columns, with minimal dead zones and channeling. Significant respiration (O₂ consumption and ∑CO₂ production) occurred in all columns, with highest respiration rates in summer. Most (78–100%) remineralized N was released as N₂ in the majority of cases, including columns with oxic porewater throughout, with only a small fraction released as NO₃⁻ from some oxic columns. A rate of 0.84–4.83×10¹⁰ mol N yr⁻¹, equivalent to 1.06–6.09×10⁻⁶ mmol N cm⁻² h⁻¹, was calculated for benthic N₂ production in the South Atlantic Bight, which can account for a large fraction of new N inputs to this shelf region. Metal and sulfate reduction occurred in long residence time columns with anoxic outflow in summer and fall, when respiration rates were highest. Because permeable sediments dominate continental shelves, N₂ production in high permeability coastal sediments may play an important role in the global N cycle.     

Single clinopyroxene thermobarometry for garnet peridotites. Part I. Calibration and testing of a Cr-in-Cpx barometer and an enstatite-in-Cpx thermometer

Experimental clinopyroxenes synthesized at 850–1500 °C and 0–60 kbar in the CMS and CMAS-Cr systems and in more complex lherzolitic systems have been used to calibrate a Cr-in-Cpx barometer and an enstatite-in-Cpx thermometer for Cr-diopsides derived from garnet peridotites. The experiments cover a wide range of possible natural peridotitic compositions, from fertile pyrolite to refractory, high-Cr lherzolite. The barometer is based on the Cr exchange between clinopyroxene and garnet. Pressure is formulated as a function of temperature and clinopyroxene composition:

Biofilm Formation and Effectiveness of Biosand Filtration Systems with Typical and Innovative Filter Media

Geotechnical and Geological Engineering - Clean drinking water is a necessity and recycling stormwater and greywater has been more appealing in the recent decades to provide filtered water for...     

Geologic constraints on the Harappa archaeological site,Punjab Province,Pakistan

The geologic setting of an urban environment affects the development of that particular urban culture. Human activities can involve devegetation, soil loosening, soil‐water and ground‐water changes, soil erosion, and changes in surface‐water hydrology. This article focuses on how the geologic resources and history of the Punjab region have greatly influenced the cultural development of the Bronze Age city of Harappa, located in northeast Pakistan. Archaeological deposits at this site date between at least 3300 B.C. and 1700 B.C. A geologic and geomorphic framework is provided which presents the relationships of the ancient Harappans with their local and regional environment, with these geologic processes affecting both the initial settlement and development of this ancient urban center. Buried soil elevation data, mapped soil distributions, and geomorphic models are used to construct an approximation of the preoccupation paleotopography beneath this site. © 2000 John Wiley & Sons, Inc.     

Relationships among water column toxins,cell abundance and chlorophyll concentrations during Karenia brevis blooms

The assumptions that Karenia brevis cell abundance and brevetoxin concentrations are proportional and that cell abundance and chlorophyll are related were tested in a 3-year field study off the west coast of Florida. The relationship between K. brevis cell abundance and brevetoxins (PbTx-2+PbTx-3) in whole water samples was strong (R²=0.92). There was no significant difference between the brevetoxin concentrations in whole water and the >0.7 μm particulate fraction. Only 7% of the total brevetoxin concentration was measured in the <0.7 μm (cell free) filtrate. The relationship of K. brevis cell abundance >5000 cells L⁻¹ with chlorophyll for all cruises and at all depths was robust (R²=0.78). These data substantiate the use of chlorophyll as a proxy for K. brevis cell abundance and K. brevis cell abundance as a proxy for brevetoxins during blooms. The ratios of the brevetoxins, PbTx-2:PbTx-3, was significantly higher in surface water than in bottom water. This information in conjunction with K. brevis growth rates may provide a useful indicator for determining the physiological state of the bloom over time.     

Wave transformation across a macrotidal shore platform under low to moderate energy conditions

We investigate how waves are transformed across a shore platform as this is a central question in rock coast geomorphology. We present results from deployment of three pressure transducers over four days, across a sloping, wide (~200 m) cliff‐backed shore platform in a macrotidal setting, in South Wales, United Kingdom. Cross‐shore variations in wave heights were evident under the predominantly low to moderate (significant wave height < 1.4 m) energy conditions measured. At the outer transducer 50 m from the seaward edge of the platform (163 m from the cliff) high tide water depths were 8+ m meaning that waves crossed the shore platform without breaking. At the mid‐platform position water depth was 5 m. Water depth at the inner transducer (6 m from the cliff platform junction) at high tide was 1.4 m. This shallow water depth forced wave breaking, thereby limiting wave heights on the inner platform. Maximum wave height at the middle and inner transducers were 2.41 and 2.39 m, respectively, and significant wave height 1.35 m and 1.34 m, respectively. Inner platform high tide wave heights were generally larger where energy was up to 335% greater than near the seaward edge where waves were smaller. Infragravity energy was less than 13% of the total energy spectra with energy in the swell, wind and capillary frequencies accounting for 87% of the total energy. Wave transformation is thus spatially variable and is strongly modulated by platform elevation and the tidal range. While shore platforms in microtidal environments have been shown to be highly dissipative, in this macro‐tidal setting up to 90% of the offshore wave energy reached the landward cliff at high tide, so that the shore platform cliff is much more reflective. Copyright © 2017 John Wiley & Sons, Ltd.     

Extraction of agar from Eucheuma cottonii and Gelidium amansii seaweeds with sonication pretreatment using autoclaving method

The effect of sonication pretreatment condition on Eucheuma cottonii and Gelidium amansii seaweed towards agar extraction wae studied.Four parameters were changed during sonication to investigate the effects on agar yield and quality.These parameters include the time interval,concentration ratio,frequency,and intensity.The highest amount of agar extracted from Eucheuma cottonii species could be obtained from the time interval of 30min,seaweed weight to solvent volume ratio of 1:20,the frequency of 35Hz,and the sonication power intensity of 30%.For Gelidium amansii species,the best agar yield also could be obtained from the time interval of 30 min,1:20 of seaweed weight to water volume ratio,the frequency of 35Hz,and power intensity of 30%.From the experiment,sonication pretreatment signifi cantly influenced the yield and properties of extracted agar.The sonication with autoclaved seaweed produced agar containing less sulfate content,which is an excellent chemical property for gel electrophoresis applications.The gelstrength of sonication with autoclaving for both seaweeds,Eucheuma and Gelidium species was the highest among those by sonication with direct heating,which proved that sonication pretreatment with autoclaving could enhance the physical properties of the agar.     

A Rapid Drawdown Event Related to Quarry Operations in a Dolomite Aquifer

Two active quarries are mining stone from the Silurian dolomite aquifer in Waukesha County in southeastern Wisconsin. The village in which the quarries are located uses local zoning to control the depth of mining and to institute a long-term water level monitoring program and well guarantee/one with the quarry owners. Water levels dropped as much as 40 feet in at least 24 residential wells surrounding the quarries over a period of a few hours to days. The rapid decline in head was caused by a single boring drilled lo a depth of 75 feel he low the floor of one quarry. The borehole penetrated a localized fracture zone under confined artesian head. Water levels recovered to previous static levels within nine days after grouting the borehole. The rapid drawdown event demonstrates the potential impact of mining in fractured aquifers. The apparent complete recovery of the aquifer demonstrates that quick response can sometimes restore an aquifer. However, the potential for blasting into a similar zone illustrates the need for a well-thought-out aquifer monitoring program and emergency response plan. The experience of the village is a good example of managing conflicting uses of a finite resource and collecting baseline data needed to make informed decisions.