Microzooplankton production in the oceans   总被引：7，自引：0，他引：7  

Landry  Michael R.; Calbet  Albert 《ICES Journal of Marine Science》2004,61(4):501-507

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Biokarst on Limestone Coasts, Morphogenesis and Sediment Production   总被引：3，自引：0，他引：3  

Jürgen  Schneider Horst  Torunski 《Marine Ecology》1983,4(1):45-63

Abstract. Biokarst-forms on limestone coasts are developed and arranged according to the bionomic zonation. The development of biokarst is the result of bioerosion, a synergistic effect of biological corrosion by endoliths and biological abrasion by grazers.
The cumulative effect of biogenic carbonate destruction leads to coastal destruction with a resulting highly profiled morphology on the limestone surfaces along the coastal profile. Under the influence of environmental factors a zonation of organisms develops which brings in turn a zonation of erosion rates (0.1-1.1 mm a^-1) resulting in biokarst-forms such as rock holes, rock pools and notches.
Products of bioerosion on limestone coasts are dissolved carbonate (by biological corrosion, 10–30% of the decomposed limestone) and particulate carbonate (by biological abrasion, 70–90% of the decomposed limestone) both of which contribute directly or indirectly to nearshore sedimentation. Size and shape of the bioerosional grains are determined by the boring pattern of the endoliths. The fine-grained sediments (maximum within the fraction 20–63 μm) contribute 3–25 % to the nearshore sediments.
Drastic changes in the biological zonation (like the mass invasion of the sea urchin Paracentrotus lividus in the Northern Adriatic since 1972 which eliminated nearly the entire macrophyte zone) due to unknown factors or pollution can have a profound effect on the bioerosion rates, altering them by as much as a factor of ten.  相似文献   

Sonographs of submarine sediment failure caused by the 1980 earthquake off northern California     

Michael E. Field  Robert K. Hall 《Geo-Marine Letters》1982,2(3-4):135-141

In 1980, a large earthquake caused extensive sediment failure on the shallow continental shelf off the Klamath River in northern California. Side-scan sonography was used to complement detailed geophysical profiling in identifying specific features and resolving modes of failure. The features include a nearly flat failure terrace mantled with sand boils, collapse craters and sediment flows, and bounded on the seaward side by a meandering continuous toe ridge. Seaward of the terrace lies a compression zone delineated by small pressure ridges. Our findings indicate a temporal progression of failure from lique-faction of shallow subsurface sand to lateral spread of intact blocks to sediment collapse and flow.  相似文献   

Storm-built sand ridges on the Maryland inner shelf: a preliminary report     

Donald J. P. Swift  Michael E. Field 《Geo-Marine Letters》1981,1(1):33-37

Several aspects of the Maryland ridge field are pertinent to the problem of ridge genesis in response to Holocene sea-level rise. There is a systematic morphologic change fromshoreface ridges throughnearshore ridges tooffshore ridges, which reflects the changing hydraulic regime. Grain size is 90° out of phase with topography, so that the coarsest sand lies between the axis of each trough and the adjacent seaward ridge crest, while the finest sand lies between each ridge crest and the axis of the adjacent seaward trough. Finally, analysis over a 43-year period on an outer ridge reveals a systematic pattern of landward flank erosion, seaward flank deposition, and seaward crest migration. These relationships support a model which explains the ridges as consequences of the up-current shift of maximum bottom shear stress with respect to the crests of initial bottom irregularities. The oblique orientation of the ridges with respect to the beach may be at least partly due to the more rapid migration rate of the ridges’ inshore ends.  相似文献   

Baltic cod recruitment - the impact of climate variability on key processes   总被引：3，自引：0，他引：3  

Koster  Friedrich W.; Mollmann  Christian; Hinrichsen  Hans-Harald; Wieland  Kai; Tomkiewicz  Jonna; Kraus  Gerd; Voss  Rudiger; Makarchouk  Andrei; MacKenzie  Brian R.; St. John  Michael A.; Schnack  Dietrich; Rohlf  Norbert; Linkowski  Tomasz; Beyer  Jan E. 《ICES Journal of Marine Science》2005,62(7):1408-1425

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Reducing the short-term mortality of juvenile school prawns (Metapenaeus macleayi) discarded during trawling     

Macbeth  William G.; Broadhurst  Matt K.; Paterson  Brian D.; Wooden  Michael E.L. 《ICES Journal of Marine Science》2006,63(5):831-839

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Prediction of wave height based on half-cycle excursion analysis     

Michel K. Ochi  Michael A. Eckhoff 《Ocean Engineering》1984,11(6):581-591

This paper presents a method to evaluate statistical properties of half-cycle excursions including extreme values. The probability density function for half-cycle excursions for an arbitrarily given wave spectrum is developed based on the Gaussian assumption. The results of numerical computations carried out using wave data obtained during hurricane Camille show that the half-cycle probability density function agrees well with the histogram constructed from the data. The extreme wave height for design consideration computed with risk parameter 0.01 is approximately 20% greater than the observed extreme height.  相似文献   

A new concept of a hull form to improve wave response characteristics for marine construction barges     

F.Y. Michael 《Ocean Engineering》1983,10(3):157-170

The object of the new hull form is to provide a single hull which possesses long natural periods of roll and heave and has substantially reduced motion response amplitudes in very high sea states. Model tests and preliminary estimates indicated that the new hull form can be designed for roll and heave motions nearly equivalent to those of much larger semisubmersible units.All existing conventional marine construction barges have rectangular cross section hull. The new hull form consists of a system of upper side tanks and lower side tanks added onto a rectangular cross section hull. The upper tanks and lower tanks form longitudinal troughs on the port and starboard sides. Structural grillage of any open type is to connect the upper and lower tanks at the side of the vessel. Figure 1 indicates a profile and a typical transverse section of the new hull form. The new hull comprises the concept of reduced water plane area which is turn results in low transverse metacentric height and low tons per in. immersion. The novel features of combining low GM_T and low TPI with extremely heavy damping and added mass of the entrained water characteristics result in very long natural periods of roll and heave and considerably small rolling and heaving amplitudes in high sea states. The open side shell plating on the side of the vessel functions to dissipate wave energy at the side of the vessel which would have otherwise been transmitted to the vessel and caused the vessel to respond. This paper presents the conceptual foundation and outline of the new hull form. Model test results are presented and implemented. Also presented is the design philosophy.  相似文献   

Intrinsic orbital coordinates on a Hamiltonian surface     

Michael E. Hough 《Celestial Mechanics and Dynamical Astronomy》1989,47(1):57-85

A reversible dynamical system with two degrees-of-freedom is reduced to a second-order, Hamiltonian system under a change of independent variable. In certain circumstances, the reduced order system may be integrated following an orthogonal curvilinear transformation from Cartesian x,y to intrinsic orbital coordinates , . Solutions for the orbit position and true time variables are expressed by: % MathType!MTEF!2!1!+- % feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGGipm0dc9vqaqpepu0xbbG8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiEaiabg2 % da9iaadAgacaGGOaGaeqOVdGNaaiilaiabeE7aOjaacMcacaGGSaGa % aeiiaiaadMhacqGH9aqpcaWGNbGaaiikaiabe67a4jaacYcacqaH3o % aAcaGGPaGaaiilaiaabccacaWGKbGaamiDaiabg2da9iabgglaXoaa % dmaabaWaaSaaaeaacaWGibWaa0baaKqaahaacqaH+oaEaeaacaqGYa % aaaOGaam4raiabgUcaRiaadIeadaqhaaqcbaCaaiabeE7aObqaaiaa % ikdaaaGccaWGfbaabaGaaGOmaiaacIcacaWGibGaey4kaSIaamyvai % aacMcaaaaacaGLBbGaayzxaaWaaWbaaSqabKqaGhaacaaIXaGaai4l % aiaaikdaaaGccaWGKbGaeqiXdqhaaa!6498! \[ x = f(\xi ,\eta ),{\rm{ }}y = g(\xi ,\eta ),{\rm{ }}dt = \pm \left[ {\frac{{_\xi ^{\rm{2}} {\ie} + _\eta ^2 }}{{2( + U)}}} \righ \]1446 1040 where U is the potential function, and z is the new independent variable. The functions f, g may be expressed by quadratures when the metric coefficients {\er},{\ie} are specified. Two second-order, partial differential equations specify {\er}, {\ie} and Hamiltonian {\tH}. Auxiliary conditions are needed because the solutions are underdetermined. For example, both sets of curvilinear coordinate lines are orbits when certain dynamical compatibility conditions between U and {\ie} (or {\er}) are satisfied. Alternatively, when orbits cross the parametric curves, the auxiliary condition {\er} = {\ie} specifies a conformal transformation, and the partial differential equation for {\tH} may be reduced to an ordinary differential equation for the orbit curve. In either case, integrability is guaranteed for Lionville dynamical systems. Specific applications are presented to illustrate direct solution for the orbit (e.g., two fixed centers) and inverse solution for the potential.  相似文献   

The use of the “spacekap” style file for delivering manuscripts in latex     

Michael Kohlhase 《Celestial Mechanics and Dynamical Astronomy》1992,53(2):205-206

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