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31.
Long-term Sensor Drift Found in Recovered Argo Profiling Floats 总被引:5,自引:0,他引:5
We recovered three Argo profiling floats after 2 to 2.5 years of operation, and recalibrated their temperature, conductivity, and pressure sensors. The results demonstrate that these floats exhibited a significant drift in salinity of −0.0074 to −0.0125, primarily due to the conductivity sensor drift. Combined with the recalibration result for another previously recovered float, the indication is that the negative salinity drift increases nearly in proportion to the operating period of floats. The increasing rate is −0.0041 (±0.0015) year−1, which yields a salinity drift of −0.016 (±0.006) for the expected float lifetime of four years. The present result suggests that reducing the float surfacing time would improve the accuracy of the salinity measurements. 相似文献
32.
Takushi?NikiEmail author Taiki?Fujinaga Mariyo?F.?Watanabe Junji?Kinoshita 《Journal of Oceanography》2004,60(5):913-917
Solid-phase microextraction (SPME) is a simple, sensitive and less destructive method for the determination of dimethylsulfide
(DMS) in seawater. Combined with detection by gas chromatography-mass spectrometry (GC-MS), the method had sufficient sensitivity
(minimum detectable concentration of DMS was 0.05 nM), and practical levels of reproducibility (relative standard deviation
≤7%) and linearity (r
2 > 0.995) over a wide concentration range (0.5 to 910 nM). The protocol developed was applied to a Sagami Bay water sample
to determine concentrations of DMS and DMSP, and in situ DMSP-lyase activity. 相似文献
33.
Eddy Shedding from the Kuroshio Bend at Luzon Strait 总被引:16,自引:1,他引:16
TOPEX/POSEDIENT-ERS satellite altimeter data along with the mean state from the Parallel Ocean Climate Model result have been used to investigate the variation of Kuroshio intrusion and eddy shedding at Luzon Strait during 1992–2001. The Kuroshio penetrates into the South China Sea and forms a bend. The Kuroshio bend varies with time, periodically shedding anticyclonic eddies. Criteria of eddy shedding are identified: 1) When the shedding event occurs, there are usually two centers of high Sea Surface Height (SSH) together with negative geostrophic vorticity in the Kuroshio Bend (KB) area. 2) Between the two centers of high SSH there usually exists positive geostrophic vorticity. These criteria have been used to determine the eddy shedding times and locations. The most frequent eddy shedding intervals are 70, 80 and 90 days. In both the winter and summer monsoon period, the most frequent locations are 119.5°E and 120°E, which means that the seasonal variation of eddy shedding location is unclear. 相似文献
34.
In this paper we analyze seismic regime and earthquake depth distribution and correlation of seismicity and mud volcanism in the Azerbaijan and the Caspian Sea region. For the present region we have calculated accurate source locations, seismic activity, earthquake repetition and released earthquake energy parameters. It is shown that the active tectonic processes in the region are concentrated within the thick sedimentary cover that we consider as a general source of contemporary stress and a main structural element responsible for the origin of regional earthquakes. The correlation of seismicity and mud volcanism is of paragenetic character. 相似文献
35.
Miller KA Assunção MG Dangerfield NJ Bandiera SM Ross PS 《Marine environmental research》2005,60(2):153-169
Biomarkers of organochlorine exposure, such as the induction of cytochrome P450 1A (CYP1A), can be used to assess the impact of environmental contaminants on the health of free-ranging marine mammal populations. The objective of the present study was to measure CYP1A in skin and liver biopsies obtained from live harbour seals (Phoca vitulina). Twelve harbour seal pups, aged three to five weeks, were captured from the Fraser River estuary, British Columbia, Canada, and temporarily held in captivity. Skin ( approximately 60 mg) and liver ( approximately 40 mg) biopsies, obtained while seals were under general anaesthesia, yielded sufficient tissue for the measurement of CYP1A by immunoblot analysis and ethoxyresorufin O-deethylase activity. A short-term exposure experiment, in which harbour seals (n=3) were treated orally with beta-naphthoflavone (BNF), resulted in increased hepatic and cutaneous CYP1A protein levels, consistent with observations in other mammals. This study is the first to measure CYP1A in skin and liver biopsies from live harbour seals and to report in vivo BNF-associated CYP1A induction in a marine mammal. The results demonstrate that microsamples collected using minimally-invasive techniques can provide toxicologically-relevant information form marine mammals. 相似文献
36.
We used transmission electron microscopy (TEM) and scanning electron microscopy (SEM) to study magmatic crystals in the Ben
Lomond rhyolite lava dome, Taupo Volcanic Center, New Zealand. Using TEM and SEM to investigate the size distributions of
these crystals, we identified three size populations: microphenocrysts (>1.2 μm wide), microlites (>0.6 μm wide), and smaller
crystals (<0.6 μm wide) which we term "nanolites". The predominant mineral phases of the microlites and nanolites are augites,
pigeonites, and hypersthenes. The compositions and microstructures within these pyroxenes indicate disequilibrium crystallization
at approximately 850–900 °C and undercoolings as high as 300 °C from equilibrium crystallization temperatures. Complex microstructures
resulting from subsolidus reactions in augite and pigeonite are consistent with moderate cooling rates within the upper obsidian
layer of the Ben Lomond rhyolite dome. This study demonstrates the existence of sub-micron magmatic crystals in a rhyolite
and illustrates the potential of TEM to provide unique information about the crystallization and cooling histories of glassy
volcanic rocks.
Received: May 8, 1995 / Accepted: November 27, 1995 相似文献
37.
38.
The linear thermal expansions of åkermanite (Ca2MgSi2O7) and hardystonite (Ca2ZnSi2O7) have been measured across the normal-incommensurate phase transition for both materials. Least-squares fitting of the high temperature (normal phase) data yields expressions linear in T for the coefficients of instantaneous linear thermal expansion, $$\alpha _1 = \frac{1}{l}\frac{{dl}}{{dT}}$$ for åkermanite: $$\begin{gathered} \alpha _{[100]} = 6.901(2) \times 10^{ - 6} + 1.834(2) \times 10^{ - 8} T \hfill \\ \alpha _{[100]} = - 2.856(1) \times 10^{ - 6} + 11.280(1) \times 10^{ - 8} T \hfill \\ \end{gathered} $$ for hardystonite: $$\begin{gathered} \alpha _{[100]} = 15.562(5) \times 10^{ - 6} - 1.478(3) \times 10^{ - 8} T \hfill \\ \alpha _{[100]} = - 11.115(5) \times 10^{ - 6} + 11.326(3) \times 10^{ - 8} T \hfill \\ \end{gathered} $$ Although there is considerable strain for temperatures within 10° C of the phase transition, suggestive of a high-order phase transition, there appears to be a finite ΔV of transition, and the phase transition is classed as “weakly first order”. 相似文献
39.
40.
The Menilite Shales (Oligocene) of the Polish Carpathians are the source of low-sulfur oils in the thrust belt and some high-sulfur oils in the Carpathian Foredeep. These oil occurrences indicate that the high-sulfur oils in the Foredeep were generated and expelled before major thrusting and the low-sulfur oils in the thrust belt were generated and expelled during or after major thrusting. Two distinct organic facies have been observed in the Menilite Shales. One organic facies has a high clastic sediment input and contains Type-II kerogen. The other organic facies has a lower clastic sediment input and contains Type-IIS kerogen. Representative samples of both organic facies were used to determine kinetic parameters for immiscible oil generation by isothermal hydrous pyrolysis and S2 generation by non-isothermal open-system pyrolysis. The derived kinetic parameters showed that timing of S2 generation was not as different between the Type-IIS and -II kerogen based on open-system pyrolysis as compared with immiscible oil generation based on hydrous pyrolysis. Applying these kinetic parameters to a burial history in the Skole unit showed that some expelled oil would have been generated from the organic facies with Type-IIS kerogen before major thrusting with the hydrous-pyrolysis kinetic parameters but not with the open-system pyrolysis kinetic parameters. The inability of open-system pyrolysis to determine earlier petroleum generation from Type-IIS kerogen is attributed to the large polar-rich bitumen component in S2 generation, rapid loss of sulfur free-radical initiators in the open system, and diminished radical selectivity and rate constant differences at higher temperatures. Hydrous-pyrolysis kinetic parameters are determined in the presence of water at lower temperatures in a closed system, which allows differentiation of bitumen and oil generation, interaction of free-radical initiators, greater radical selectivity, and more distinguishable rate constants as would occur during natural maturation. Kinetic parameters derived from hydrous pyrolysis show good correlations with one another (compensation effect) and kerogen organic-sulfur contents. These correlations allow for indirect determination of hydrous-pyrolysis kinetic parameters on the basis of the organic-sulfur mole fraction of an immature Type-II or -IIS kerogen. 相似文献