Experiments withLaminaria japonica were conducted in Meidao Bay and Pier Bay, Qingdao, China, Nitrogen-starved plants were fertilized intermittently with 7.1
mM NH4−N solution for 1 hour at 3 day intervals, after which chlorophyll a, fucoxanthin, chlorophyll c and β-carotene contents were
analyzed. Photosynthetic and growth rates of plants and nitrogen content of seawater were determined. their contents of chlorophyll
a, fucoxanthin, chlorophyll c and β-carotene were 1.65, 0.67, 0.33 and 0.06 mg.dm−2 respectively, or 2.46, 2.03, 1.86 and 1.81 times those of the controls. The ratio of fucoxanthin to chlorophyll a in nitrogen-enriched
plants was lower than that of the controls. Normal growth rate of the plants (2 cm·day−1 in length) were reached when the chlorophyll a content exceeded 0.1 mg·g−1 fresh wt., indicating that chlorophyll a content can serve as an indicator of normal growth.
Experimental results show that seawater is regarded as fertile for the normal growth ofLaminaria if the total inorganic nitrogen (including ammonium salt, nitrate and nitrite) content in seawater is about 2 μm, and infertile
if less than 1 μm, in which case fertilizer should be applied.
Contribution No. 1703 from the Institute of Oceanology, Academia Sinica 相似文献
1INTRODUCTIONGroundwater in Changchun City assures about 45% of total water supply. Drinking water supply of Chang-chun City was mostly served by surface water from Shitoukoumen and Xinlicheng reservoirs located in the east and south of the city (ZHANG, 1993). However, with the development of urban construction the ground-water especially from deep boreholes is also used for drinking purpose in suburban areas. The urbanization process in Changchun City threatens the groundwater quali… 相似文献
Using earthquakes relocated in north‐east Taiwan, we estimated b‐value distribution along a cross‐section located near the Ryukyu slab edge, and four b‐value anomalous areas are evidenced: (1) a high b‐value body lying on top of a low Vp, low Vs and high Vp/Vs sausage‐like body was considered as a region of enhanced partial melt or water supply above which seismicity occurs; (2) beneath the Ilan Plain, an anomalous area characterized by b‐values slightly higher than 1.1 might give evidence to the magma conduits to the Kueishantao Island; (3) above the Ryukyu Wadati‐Benioff zone, at depths ranging from 90 to 110 km, a high b‐value anomaly might correspond to the depth where dehydration occurs in the subducting oceanic plate; and (4) a low b‐value area located within the Ryukyu slab, at depths ranging from 70 to 90 km, might be linked to the compressive mechanisms shown by focal mechanisms and the bending of the subducting plate. 相似文献
Zircon grains were selected from two types of ultrahigh-pressure (UHP) eclogites, coarse-grained phengite eclogite and fine-grained massive eclogite, in the Yukahe area, the western part of the North Qaidam UHP metamorphic belt. Most zircon grains show typical metamorphic origin with residual cores in some irregular grains and sector, planar or misty internal textures on the cathodoluminescence (CL) images. The contents of REE and HREE of the core parts of grains range from 173 to 1680 μg/g and 170 to 1634 μg/g, respectively, in phengite eclogite, and from 37 to 2640 μg/g and 25.7 to 1824 μg/g, respectively, in massive eclogite. The core parts exhibit HREE-enriched patterns, representing the residual zircons of protolith of the Yukahe eclogite. The contents of REE and HREE of the rim parts and the grains free of residual cores are much lower than those for the core parts. They vary from 13.1 to 89.5 μg/g and 12.5 to 85.7 μg/g, respectively, in phengite eclogite, and from 9.92 to 45.8 μg/g and 9.18 to 43.8 μg/g, respectively, in massive eclogite. Negative Eu anomalies and Th/U ratios decrease from core to rim. Positive Eu anomalies are shown in some grains. These indicate that the presence of garnet and the absence of plagioclase in the peak metamorphic mineral assemblage, and the zircons formed under eclogite facies conditions. LA-ICP-MS zircon U-Pb age data indicate that phengite eclogite and massive eclogite have similar metamorphic age of 436±3Ma and 431±4Ma in the early Paleozoic and magmatic protolith age of 783–793 Ma and 748–759 Ma in the Neo-proterozoic. The weighted mean age of the metamorphic ages (434±2 Ma) may represent the UHP metamorphic age of the Yukahe eclogites. The metamorphic age is well consistent with their direct country rocks of gneisses (431±3 Ma and 432±19 Ma) and coesite-bearing pelitic schist in the Yematan UHP eclogite section (423–440 Ma). These age data together with field observation and lithology, allow us to conclude that the Yukahe eclogites were Neo-proterozoic igneous rocks and may have experienced subduction and UHP metamorphism with continental crust at deep mantle during the early Paleozoic, therefore the metamorphic age of 434±2 Ma of the Yukahe eclogites probably represents the continental deep subduction time in this area.
In this paper, the morphological characters of eggs and larvae ofSardinella aurita (Cuvier & Valenciennes), its spawning ground, spawning seasons and spawning conditions have been studied.
Sardinella aurita likes to breed in the upwelling area and selects the Waixie fishing ground as its main spawning ground. The months from February
to September are its spawning seasons, reaching its peak in April. In the main spawning ground, the temperature of the surface
layer was found to be 24.4–25.2°C, the salinity 33.87–34.07%. and the depth of water between 34–60m.
The distribution of the larvae is closely related to the distribution of plankton, the path of migration of adult fish, and
the current direction of the water system.
In order to protect fishery resources, it is necessary to prohibit catching the spawning fish in the Waixie fishing ground
in April, and the catching of immatures from March to June.
This paper was published in Chinese inOcean. Limn. Sinica14(3): 240–248, 1983. 相似文献
High-resolution Hα filtergrams (0.2″) obtained with the Swedish 1-m Solar Telescope resolve numerous very thin, thread-like
structures in solar filaments. The threads are believed to represent thin magnetic flux tubes that must be longer than the
observable threads. We report on evidence for small-amplitude (1 – 2 km s−1) waves propagating along a number of threads with an average phase velocity of 12 km s−1 and a wavelength of 4″. The oscillatory period of individual threads vary from 3 to 9 minutes. Temporal variation of the
Doppler velocities averaged over a small area containing a number of individual threads shows a short-period (3.6 minutes)
wave pattern. These short-period oscillations could possibly represent fast modes in accordance with numerical fibril models
proposed by Díaz et al. (Astron. Astrophys.379, 1083, 2001). In some cases, it is clear that the propagating waves are moving in the same direction as the mass flows. 相似文献
