Geochemistry of re and trace elements in ferromanganese nodules and their genesis

Trace and RE element geochemistry and genesis have been studied with respect to ferromanganese nodules from the sediments of the Pacific, Atlantic and Indian oceans.     

Chemical mass transfer from the Changjiang River to the sea

1. The nonanthropogenic SO₄ in the Changjiang River stems from weathering and oxidation of sulphate and sulphite minerals, while the anthropogenic SO₄ here is attributed to acid rain containing H₂SO₄ formed by atmospheric sulphur oxides derived from the burning of fossil fuels in the region of the lower reaches. Ca and Mg are probably derived from weathering of carbonate minerals, but possibly less from weathering of silicate minerals.
2. The Changjiang River estuary is characterized by two—layer flow based on the salinity section of the estuary, so a model of two—layer exchange of water—body in the Changjiang River estuary can be advanced.
3. The presence of SO₄ and K at stations H₁₄ and H₁₅ were found most likely to be due to the addition and removal processes, that of the other major consituents may be mainly controlled by physical mixing in this estuary.

     

Bioreactor technology for production of valuable algal products

INTRODUCTIONManystudiesonvascularplantSduringthenontwperiodhavedrireP0redinChinaandabroad.TherearefeWreportSonwhethertherearesomevasctilarplantS,andhowmanyspedessurvive,underice,andontheirbiomassesandphotosyntheticproduCtivitiesduringwinter,espedal1yduringbeAfpinchLillyamepe0ylenctal.,l976,Liuetal.,l994).WeimtlycarriedoutaseadriontheunderforvascularplantsdurinwinderinsomewaterbodieswherevascularplantSgrowluxdrianhydurinInildareonsinnorthemareas,soastoimproveourknowedgeofvascularplaflt…     

Distribution and migration of the common squidTodarodes pacificus in the Yellow Sea

Study of the distribution and migration of the common squid,Todarodes pacificus Steenstrup,basedon the index of important fishing ground(P) and fisheries statistics on the Yellow Sea and northern EastChina Sea during 1980—1991 showed that:1.Its catch in the fishing period(June to November) is 91.77% of the annual yield.The fishingground distributes over the northem and middle Yel1ow Sea and adjacent area of the Changjiang Estuary.2. It over-winters in the northem East China Sea and waters adjacent to Goto Island from De-cember to February and spawns in waters near Haijiao Is1and and west of Kyushu. The main stock mi-grates along 123°30′E to the ChangJiang Estuary, Haizhou Bay. offsea from Shidao to Qingdao,mideastern Yellow Sea, and offsea Weihai and Haiyang Island succesively for feeding after April. The sur-plus stock migrates again to the wintering ground in December.3.The favorable feeding temperature is 6-23℃(optimum of l3-20℃ in the Changjiang Estua-ry and 7-13℃ in the northern and middle Yel     

Palynological assemblages from the holocene sediments of the Changjiang (Yangtze) River Delta and its implications

The palynolpgical study on the Quaternary sediments of 42 cores in the region of the Yangtze River Delta and the sections of 4 relics had been done since 1960. Palynological assemblages from the region of the Yangtze River Delta, showing obviously .common characteristics but with slight differences because of the vast areas covered, can be divided into five spores and pollen zones and three subzones in ascendant order:I.Quercus alienc-Pinus-Cupressaceae-Chenopodiaceae spores and pollen zone reflecting the cool, then cold and dry climate--Preboreal.II.Quercus dentata-Quefcus acutissima-Pinus-Castanea-Artemisia spores and pollen zone reflecting the temperate and cool, but a little dry climate--Boreal.III.Quercus glauca-Caslanopsis-Myrica-Caslanea spores and pollen zone reflecting the hot and moist climate--Atlantic.IV.Quercus acutissima-Pinus-Castanea-Quercus glauca- Chenopodiaceae spores and pollen zone reflecting the warm, and a little dry climate--Subboreal.V.Quercus acutissima-Costarica-Quercus glauca     

Characteristics of organic geochemistry of sediments in the northern part of the South Huanghai Sea

It is known that the organic matter in the upper layer of sediments gets lost fast, but not in the South Huanghai Sea (Yellow sea). Some of the major characteristics of organic geochemistry of sediments in the South Huanghai Sea can be summarized as follows:1. The contents of organic carbon and bitumen increase with the decrease in grain size.2.Loss of organic matter is closely related to grain size but less so in clay sediments.3.The contents of bitumen and hydrocarbon are low, about n ×102 ppm for bitumen and n ×10 ppm for hydrocarbon.A scattered show of organic matter does not necessarily indicate the presence of petroleum in recent marine sediments.In research into the genesis of petroleum, people pay more attention to the study of the organic geochemistry of recent marine sediments. How much organic materials was lost during the deposition up to the diagenesis ? The problem is as important as the study on the transformation of organic matter. This study on the organic geochemistry of the sediment     

The movement of bed-load discharge near the shore of Shijiu harbour

Shijiu Harbour is to be constructed at southern Shandong as an important shipping center with a docking capacity of 100 thousand tonnages of a single vessel.Tides and tidal currents were frequently observed at three different layers from December 1979 to April 1980. Bed-load discharge was sampled and calculated for different weather conditions. Some of the results are as follows:1. The amount of bed-load discharge is 0.1359 g/cm2/day during the spring tide, 0.09 g/cm2/day during the neap tide, 0.488 g/cm2/day during storm weather, which is four times as high as that during average tides.2. The maximum amount of the sediments that settle to the waterway is less than 46.7768 g/cm2 per year, therefore the waterway will not be blocked by the transported sand and clay even after a storm weather.     

Analysis of Yellow Sea low-frequency current variation

Low frequency (LF) current (period>25 hour) variation at 5 stations in Jiaozhou Bay. Shijiousuo, and the central part of the Yellow Sea were studied by analyzing the observed long-period current data series in the study area.1) There are obvious periods of 3 and 5 days in the LF current spectra. The energy spectral value of LF current of a 5 day period is remarkably larger than that of a 3 day period. These periods reflect the correlations between the LF current variation and the LF water level variation.2) The feet that the 15-day period in the LF current spectra corresponds to the semi-monthly celestial tide period indicates that the tide-induced residual current is an important and most evident LF current component in the bay.3) The LF current spectral energy density in the northward direction is much larger than that in the eastward direction. This shows the frequency and strength of the wind field in the northward direction are evidently larger than that in the eastward direction.     

An approach to the transgressive sedimentary pattern of the present continental shelf

On the basis of our study of the present sediments in the northern part of the continental shelf of the South China Sea, this article clarifies our views that a "three-zone pattern" is the basic feature of transgression-type sedimentation.The classification of transgression-type sedimentation of the present continental shelf is based on: the close relationships between the formation of the present continental shelf and the position of the low sea level of the Wiirrn glacial stage, the genetic types and environmental features of sedimentary zoning, the relationship between the formation of glauconite with different maturity and the migration of coastline, the speed of transgression, and the overlying speed of sedimentation. We put forward the genetic name of the "three-zone pattern" to denote:1.The inner zouu, river mouth-coastal current sedimentary area;2.The intermediate zone, coastal current-sea current scouring-sedimentary area;3.The outer zone, sea current scouring area.All these are of significance     

Flume simulation of wave-induced release of internal dissolved nitrogen in Taihu Lake, China

A wave flume simulator was used to study internal nitrogen release from the surface sediment collected from Taihu Lake,China.Particulate nitrogen concentrations were positively correlated with the concentrations of suspended solids,primarily from surface erosion related to the shear stress and duration of wave action.In response to 4 cm-and 10 cm-high wave production representing waves generated in Taihu Lake by gentle and gusty winds,respectively,the mean dynamic release rate of ammonium(NH+4) from the sediment to the overlying water was 1×10-3 mg/(m2.s) and the NH4+ concentration in the overlying water increased by 0.016 mg/L,indicating that waves resulting from strong wind can induce the rapid release of dissolved nitrogen from Taihu Lake sediments.The decrease in interstitial NH+4 concentrations at all sediment depths was associated with an increase in NH4+ concentrations in the overlying water by 0.01 mg/L,showing that sediment below the eroded layer was the main source of internal nitrogen release.Changes in the interstitial dissolved oxygen and NH+4 concentrations showed that wave-induced pore water movement can greatly increase the diffusion rate,and that these effects can influence the sediment to a depth of at least 15 cm.Diffusion induced by pore water movement may be very important for the formation of an active sediment layer in Taihu Lake.     

Vertical zonation of horticultural farming in the Alaknanda basin of Garhwal Himalaya, India

Introduction In the Alakananda Basin, undulating terrain constitutes the most fragile elements of the ecosystem. Traditional economy rests on the terraced cultivation with extremely limited viability to expansion and modernization. Consequently, low economic return remains the characteristic feature of the agrarian landscape. It is the common experience that the ecological conditions of the basin are more suited to fruit cultivation rather than cereal farming (Atkinson 1889). Along with frui…     

The community structure and seasonal dynamics of plankton in Bange Lake,northern Tibet,China

The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three times per month from May 2001 to July 2002. Salinity ranged from 14 to 146. The air and water temperature exhibited a clear seasonal pattern, and mean annual temperatures were approximately 4.8°C and 7.3°C, respectively. The lowest water temperature occurred in winter from December to March at-2°C and the highest in June and July at 17.7°C. Forty-one phytoplankton taxa, 21 zooplankton, and 5 benthic or facultative zooplankton were identifi ed. The predominant phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Dunaliella salina, and Spirulina major. The predominant zooplankton species included H olophrya actra, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, and A rctodiaptomus salinus. The mean annual total phytoplankton density and biomass for the entire lake were 4.52×10~7 cells/L and 1.60 mg/L, respectively. The annual mean zooplankton abundance was 52, 162, 322, and 57, 144 ind./L, in the three sublakes. The annual mean total zooplankton biomass in Lakes 1–3 was 1.23, 9.98, and 2.13 mg/L, respectively. The annual mean tychoplankton abundances in Bg1, 2, and 3 were 47, 67, and 654 ind./L. The annual mean tychoplankton biomass was 2.36, 0.16, and 2.03 mg/L, respectively. The zooplankton biomass(including tychoplankton) in the lake was 9.11 mg/L. The total number of plankton species in the salt lake was signifi cantly negatively correlated with salinity.     

Experimental study of dissolved oxygen transport by regular waves through a perforated breakwater

The perforated breakwater is an environmentally friendly coastal structure,and dissolved oxygen concentration levels are an important index to denote water quality.In this paper,oxygen transport experiments with regular waves through a vertical perforated breakwater were conducted.The oxygen scavenger method was used to reduce the dissolved oxygen concentration of inner water body with the chemicals Na_2SO_3 and Co Cl_2.The dissolved oxygen concentration and wave parameters of 36 experimental scenarios were measured with different perforated arrangements and wave conditions.It was found that the oxygen transfer coefficient through wave surface,K_1a_1,is much lower than the oxygen transport coefficient through the perforated breakwater,K_2a_2.If the effect of K_1a_1 is not considered,the dissolved oxygen concentration computation for inner water body will not be greatly affected.Considering the effect of a permeable area ratio α,relative location parameter of perforations δ and wave period T,the aforementioned data of 30 experimental scenarios,the dimensional analysis and the least squares method were used to derive an equation of K_2a_2(K_2a_2=0.0042α~(0.5)δ~(0.2)T~(-1)).It was validated with 6 other experimental scenarios data,which indicates an approximate agreement.Therefore,this equation can be used to compute the DO concentration caused by the water transport through perforated breakwater.     

The internal hydrographic structure of the Huanghai cold water mass (HCWM) in summer

The deep and bottom water within the Huanghai Cold Water Mass (HCWM) in summer was, for a long time, considered as a homogeneous body of water. Various investigations in recent years showed this may not be true.After a detailed analysis of the most recently obtained refined CTD data and other historical hydrographic data at our disposal, some significant results have been obtained.1.It is definitely shown that the Huanghai Warm Current (HWC) did not enter the HCWM in summer. However, there exist two types of second class water masses within the HCWM in summer. They are: (1) a water mass with low temperature and low salinity, which was formed in the preceding winter by a vertical mixing process locally, and (2) a water mass of relatively high temperature and high salinity, which is the remanent body of the HWC that entered the HCWM in preceding seasons, but was completely cut off from its source in summer. The spreading of these two water masses, the existence of a frontal zone at the boundary of the two     

Secondary metabolites of a deep sea derived fungus Aspergillus versicolor CXCTD-06-6a and their bioactivity

In order to obtain novel secondary metabolites, a deep sea inhabiting fungus Aspergillus versicolor CXCTD-06-6a was investigated. One new diketopiperazine brevianamide W(1a), as well as five known diketopiperazine alkaloids, diketopiperazine V(1b), brevianamide Q(2), brevianamide R(3), brevianamide K(4), and brevianamide E(5), were isolated from the Et OAc extract of the fermentation broth. Their structures were elucidated by spectroscopy techniques(NMR, MS). The six compounds exhibited moderate radical scavenging activity against DPPH with clearance ratio of 55.0%(1a and 1b), 53.7%(2), 46.2%(3), 61.4%(4) and 19.3%(5) at a concentration of 13.9 μmol L-1, respectively; while the positive control ascorbic acid showed a ratio of 70.3% at the concentration of 28.4 μmol L-1.     

Cadmium flux and genotoxicity in an experimental marine food chain

Cadmium flux through a lab food chain (Phaeodactylum tricornutum Bohlin- Penaeus orientate Kishinouye- Hexagrammos otakii Jordan et Starks) and its genotoxicity were investigated. The results are as follows:1. High doses of cadmium (>0.003 mol / L) induced flocculation and quick precipitation of Phaeodactylum tricornutum; lower doses of cadmium could be adsorbed on and absorbed by P. tricornutum without delaying its growth. Cadmium concentrations in algae increased with dosage, and cadmium ions removed from the medium were in proportion to dosage. In vivo chelation and organizable combination of absorbed cadmium ions by metabolites of P. tricornutum can be considered as bio-detoxification.2. Cadmium concentration decreased in the transfers from P. tricornutum to P. orientalis and from the latter to H. otakii. Transfer coefficient of cadmium in the first flux was 66.6% and 29.9% in the second. Results of t tests showed that mutagenicity of ashed internal organs of experimental prawns was significantly hi     

Combined effects of light intensity and NH^＋4-enrichment on growth,pigmentation, and photosynthetic performance of Ulva prolifera （Chlorophyta）

The aim of this study was to investigate the effects of light intensity and enhanced nitrogen supply on the growth and photosynthesis of the green-tide macroalga, Ulva prolifera. Thalli of U. prolifera were grown in natural or NH 4 +-enriched seawater under two different light intensities for 7 days, and then the growth rate, pigmentation, and photosynthetic performance of the thalli were evaluated. The results show that the relative growth rate(RGR) was markedly higher under the high light level than under the low light level. Enrichment with NH 4 + enhanced the RGR under high light intensity, but did not affect RGR under low light intensity. In low light conditions, NH 4 +-enrichment resulted in a marked decrease in the maximal photosynthetic rate( P m) and the maximum carbon fixation rate( V max), but it did not affect the half saturation constant for carbon( K 0.5) or the ratio of V max to K 0.5, which reflects the carbon acquisition efficiency. In high light conditions, P m, K 0.5, and the dark respiration rate( R d) increased under NH 4 + enrichment, but V max and the V max / K 0.5 ratio decreased. Regardless of the light intensity, NH 4 +-enrichment did not affect the apparent photosynthetic efficiency( α), which refl ects the ability of the alga to use light energy at low light levels. Under both low and high light intensities, the chlorophyll a(Chl a), chlorophyll b(Chl b), and carotenoids(Car) contents in thalli were higher in NH 4 +-enriched than in natural seawater, except that there was a decrease in the Chl b content of thalli in NH 4 +-enriched seawater under low light intensity. Therefore, NH 4 + enrichment improved the growth and photosynthetic performance of U. prolifera under high light intensity, but not under low light intensity. We discuss the possible mechanisms underlying these physiological responses.     

The hydrochemical features of salt lakes in Qaidam Basin

There are 37 lakes in the Qaidam Basin: 1 freshwater lake, 6 brackish-water lakes, 2 saline-water lakes and 28 salt lakes. The pH value of salt lake brines is 7.014 on the average, and the average total mineralization is 340.75 g/1. Their water bodies belong mainly to the five-component equilibrium system,: Na, K, Mg//SO₄, Cl-H₂O, which can be further grouped into sodium-magnesium sulfate subtype, magnesium sulfate subtype, chloride transition subtype and chloride type water by their hydrochemical property. The salt lake brines of the first salt forming epoch (N₂−Q₃) were of the sulfate type. In the second salt forming epoch (Q₃−Q₄), some of them were of the chloride type. The pH value of brines decreases with the increase of total mineralization. The pH value is lower when the total mineralization is from 50–310 g/l and higher when the total mineralization is from 310–355 g/l, however, when the total mineralization is higher than 355 g/l, the pH value decreases slowly again. The total mineralization of the chloride type and the chloride transition subtype brine is higher than the sulfate type, being 310–530 g/l, 310–470 g/l, and less than 355 g/l in that order. Of the 40 chemical compositions in the saline lake brines in Qaidam Basin, potassium is mainly concentrated in the chloride type and chloride transition subtype brine, boron and lithium mainly in the sulfate type. Evaporation experiments show that boron and lithium are accumulated in concentrated brine until crystallization of bischofite takes place. Potassium is also accumulated in concentrated brine during the salt forming stage, but its concentration decreases with the increase of total mineralization during the potassium forming stage. This paper was published in Chinese inOcean. et Limn. Sinica;15 (4):341–359, 1984.     

Effects of nitrogen specification and culture method on growth of Enteromorpha prolifera

Eutrophication, which is the enrichment of a water mass with inorganic and organic nutrients that support plant growth, is a key factor in stimulating phytoplankton growth. In this study, we determined the effects of various nitrogen sources, different nitrogen concentrations in the culture medium, and two culture methods on the growth of the green alga, Enteromorpha prolifera. The relationship between the specific growth rate of E. prolifera and NO3--N concentration was consistent with that estimated using the Monod equation (R2 = 0.9713, P < 0.01). In the NO3--N medium, the maximum specific growth rate was calculated to be 0.1634/d and the semi-saturation constant was calculated to be 16.86 μmol/L. Our results show that E. prolifera can effectively utilize NH4+-N, NO3--N, and NO2--N and urea-N in the range of 5 to 50 μmol/L. NH4+-N was preferentially assimilated by E. prolifera, and urea-N was favorable for long-term growth.     

Holocene temperature records from the East China sea mud area southwest of the Cheju Island reconstructed by the U 37 K′ and TEX86 paleothermometers

As an important marginal sea under the influences of both the Changjiang River and the Kuroshio, the East China Sea (ECS) environment is sensitive to both continental and oceanic forcing. Paleoenvironmental records are essential for understanding the long-term environmental evolution of the ECS and adjacent areas. However, paleo-temperature records from the ECS shelf are currently very limited. In this study, the U ₃₇ ^K′ and TEX₈₆ paleothermometers were used to reconstruct surface and subsurface temperature changes of the mud area southwest of the Cheju Island (Site F10B) in the ECS during the Holocene. The results indicate that temperature changes of F10B during the early Holocene (11.6–6.2 kyr) are associated with global climate change. During the period of 6.2–2.5 kyr, the similar variability trends of smoothing average of ΔT (the difference between surface and subsurface temperature) of Site F10B and the strength of the Kuroshio suggest that the Kuroshio influence on the site started around 6.2 kyr when the Kuroshio entered the Yellow Sea and continued to 2.5 kyr. During the late Holocene (2.5–1.45 kyr), apparent decreases of U ₃₇ ^K′ sea surface temperature (SST) and ΔT imply that the direct influence of the Kuroshio was reduced while cold eddy induced by the Kuroshio gradually controlled hydrological conditions of this region around 2.5 kyr.