球等鞭金藻的生长速率与培养液中营养盐的关系研究   总被引：2，自引：0，他引：2  

孙颖颖  王长海 《海洋科学》2006,30(1):78-83

通过一次培养试验,分别研究了培养液中营养盐N、P、Si、Fe浓度变化对球等鞭金藻(Isochrysisgalbana)生长速率的影响。实验结果表明,生长速率与单一营养盐浓度符合Monod方程,而且将Monod方程扩展得到了可以表示多种营养盐对球等鞭金藻生长的复合限制模式。  相似文献   

Nutrient and Plankton Dynamics in the NE and NW Gyres of the Subarctic Pacific Ocean     

Paul J. Harrison  Frank A. Whitney  Atsushi Tsuda  Hiroaki Saito  Kazuaki Tadokoro 《Journal of Oceanography》2004,60(1):93-117

The western subarctic gyre (WSG) and the eastern Alaska Grye (AG) on each side of the subarctic North Pacific, have many similarities. In both gyres, macronutrients are generally high and chl is low, and hence both gyres are High Nitrate, Low Chlorophyll (HNLC) regions. Despite the general similarities between these two gyres, there are many important differences. The time series station established at Stn KNOT on the southwest edge of the WSG and two in situ mesoscale iron enrichment experiments at each of the gyres has provided more information on iron concentrations, the dual role of iron and silicate limitation and seasonal cycles in the gyres. There is more seasonality in many parameters at Stn KNOT than at Stn P. There is an increase in Chl and primary productivity at Stn KNOT in May followed by increased iron limitation in summer. Low DIC:NO₃ ratios and high Si:NO₃ ratios in the WSG, indicate lower calcification and higher diatom production than at Stn P. The sources of iron for these areas are still not clear, but horizontal transport of iron rich coastal water and vertical transport could be important sources at certain times of the year in addition to dust input. Satellite images show that chl-rich coastal waters occasionally extend to the vicinity of Stn KNOT and therefore Stn KNOT may not always represent conditions in the main part of the WSG. This review focuses mainly on a comparison of Stn KNOT and Stn P, two time series stations on the edge of two very large gyres. At present, we have a limited understanding of the temporal and spatial variability within each of these large gyres. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

The nutrient and trace metal geochemistry of a dredge plume     

John M. Tramontano  W.F. Bohlen 《Estuarine, Coastal and Shelf Science》1984,18(4):385-401

Field sampling of the dissolved and particulate material field downstream of a large volume bucket dredge operating in the lower Thames River estuary near New London, Connecticut, was conducted in order to examine the magnitude and character of the dredge-induced resuspension. These data indicate that large amounts of dissolved phosphate, ammonia, silica, manganese, copper and particulate materials are released into the water column, whereas cadmium concentrations were unaffected. Concentrations in the vicinity of the dredge exceed background levels by two to nine times for the dissolved materials and by two orders of magnitude for particulates. During the ebb cycle, downstream material concentrations decrease rapidly to background within approximately 180 m for dissolved materials and 700 m for particulates.Two mechanisms were found to control the distribution of materials downstream of the dredge: (a) physical transport, including advection, turbulent mixing and diffusion, and (b) geochemical processes (i.e. adsorption, desorption, precipitation, dissolution, etc.). The concentration of dissolved materials downstream of the dredge decrease at a first order exponential rate. The downstream distribution of the dissolved ammonia and silica was found to be consistent with the reactivity experiments (Figure 8) which predicted that PO₄ would undergo a decay in concentration in the presence of suspended sediments. Absorption of phosphate onto suspended sediments and gravitational settling of the suspended particulates were the processes. Manganese and copper underwent a dual transformation which involved an initial dissolution, followed by flocculation and possible coprecipitation as MnO₂. Cadmium concentrations in the water column were unaffected by the dredging process due to low pore water concentrations.The observed spatial distribution indicates that dredge-induced injection of dissolved and particulate materials is primarily a near field phenomenon producing relatively minor variations as compared to those caused by naturally occurring storm events. These latter systems have been shown (Tramontano, 1978; Bohlen et al., 1979) to produce estuary-wide variations in suspended materials, PO₄ and NH₄ concentrations increasing the mass of materials in suspension by at least a factor of two. This increase in total suspended load, PO₄ and NH₄, is nearly an order of magnitude larger than that produced by the dredge.  相似文献   

福建北部沿岸与台湾北面海域的水化学特性     

陈水土  阮五崎 《热带海洋学报》1995,(1)

根据１９８８年夏季台湾海峡海域的调查资料讨论福建北部沿岸和台湾北面海域水化学的区域性特征。结果表明，福建沿岸上升流是西部海域诸化学要素分布的控制因素。台湾北面海域（２５°５０′－２６°４０′Ｎ，１２１°４５′－１２２°３０′Ｅ）水体下层出现局部冷水抬升，福建沿岸和台湾北面海域都具有低溶解氧且不饱和、高营养盐、低温、高盐的特征，溶解氧、诸营养盐与温度、盐度分别有良好的相关关系。  相似文献   

芦苇湿地对氮磷污染物质的净化效应及其价值初步估算——以苏北盐城海岸带芦苇湿地为例   总被引：8，自引：0，他引：8  

欧维新  高建华  杨桂山 《海洋通报》2006,25(5):90-96

对在不同污灌强度下的苏北盐城海岸带两片芦苇湿地的调查发现:在新洋港,氮磷营养物质在2km长的灌渠中的自净率为18.3%～45.6%;苇田净化率在87.08%～95.65%之间;在黄沙港,由于灌溉水体中污染物含量过高,灌渠中的自净率在6.5%～8.7%之间,苇田净化率为61.3%～86.2%,均低于新洋港,而芦苇湿地单位面积净化效果则是新洋港处的3.2～18.5倍。净化效果的差异,说明对苏北盐城海岸带芦苇湿地净化功能的利用可能还存在较大的潜力和空间。单位面积的芦苇净化价值为1120元/hm2·a,比国际估算结果偏低,表明对海岸湿地这种处于生态过渡带的湿地类型中营养物质及其他污染物质的净化研究还有待进一步的实验和研究,这方面工作的开展也具有现实的重要性和必要性。  相似文献   

Distribution of nitrogenous nutrients and denitrifiers strains in estuarine sediment profiles of the Tanshui River, northern Taiwan   总被引：1，自引：1，他引：1  

L.F. Fan  W.Y. Shieh  W.F. Wu  C.-P. Chen   《Estuarine, Coastal and Shelf Science》2006,69(3-4):543

Chemical profiles of both oxidized (nitrate and sulfate) and reduced (ammonium, sulfide, acid-volatile sulfide [AVS], and pyrite) materials and the corresponding distribution of denitrifier microbial communities were measured at low tide in sediments at Guandu in the estuary of the Tanshui River, northern Taiwan in August 2002. Denitrifier strains were isolated for physiological and phylogenic analyses. Based on the distribution of nitrogenous compounds and denitrifier abundances, the vertical profile of Guandu sediments could be separated into four layers: a mixed layer (the top 1 cm of depth, respectively containing 0.82–2.37 and 535.9–475.0 μM of nitrate and ammonium), a nitrate-concentrated layer (1–5 cm in depth, 2.37–0.53 and 475.0–1192.1 μM, respectively), a denitrifier-aggregation layer (5–7 cm in depth, 0.53–0.72 and 1192.1–1430.1 μM, respectively), and an ammonium-enriched layer (7–12 cm in depth, 0.72–0.78 and 1430.1–2196.6 μM, respectively). Denitrifier strains were detected in all layers except for the mixed layer. A variety of metabolic processes by these strains may occur in different layers. Bacillus jeotgali-, Bacillus sphaericus-, and Bacillus firmus-related strains isolated from the nitrate-concentrated layer may be involved in the nitrification-denitrification coupling process due to the relatively low nitrate concentrations (maximum = 2.37 μM), and may contribute to denitrification not nitrification. Bacillus bataviensis- and B. jeotgali-related strains isolated from the denitrifier-aggregation layer comprised the predominant denitrifier population (3.64 × 10⁴ cells/g of denitrifier abundance). They possess the ability of dissimilatory nitrate reduction to ammonium (DNRA). Bacillus jeotgali-related strains and two newly identified strains of GD0705 and GD0706 isolated from the ammonium-enriched layer possibly use fermentative processes as the main metabolic pathway instead of denitrification when nitrate is scarce, and this further supports the high ammonium concentrations (up to 2.20 mM) found in the Guandu sediments. In addition, spore formation also enhances the chance of survival of these strains in the face with such a nitrate-deficient environment.  相似文献   

Seasonal variations in nutrients and chlorophyll-a concentrations in the Northern east China sea     

Dongseon Kim  JeongHee Shim  Sinjae Yoo 《Ocean Science Journal》2006,41(3):125-137

Nutrients, chlorophyll-a, particulate organic carbon (POC), and environmental conditions were extensively investigated in the northern East China Sea (ECS) near Cheju Island during three seasonal cruises from 2003 to 2005. In spring and autumn, relatively high concentrations of nitrate (2.6~12.4 μmol kg^-1) and phosphate (0.17~0.61 μmol kg^-1) were observed in the surface waters in the western part of the study area because of the large supply of nutrients from deep waters by vertical mixing. The surface concentrations of nitrate and phosphate in summer were much lower than those in spring and autumn, which is ascribed to a reduced nutrient supply from the deep waters in summer because of surface layer stratification. While previous studies indicate that upwellings of the Kuroshio Current and the Changjiang (Yangtze River) are main sources of nutrients in the ECS, these two inputs seem not to have contributed significantly to the build-up of nutrients in the northern ECS during the time of this study. The lower nitrate:phosphate (N:P) ratio in the surface waters and the positive correlation between the surface N:P ratio and nitrate concentration indicate that nitrate acts as a main nutrient limiting phytoplankton growth in the northern ECS, contrary to previous reports of phosphate-limited phytoplankton growth in the ECS. This difference arises because most surface water nutrients are supplied by vertical mixing from deep waters with low N:P ratios and are not directly influenced by the Changjiang, which has a high N:P ratio. Surface chlorophyll-a levels showed large seasonal variation, with high concentrations (0.38~4.14 mg m^-3) in spring and autumn and low concentrations (0.22~1.05 mg m^-3) in summer. The surface distribution of chlorophyll-a coincided fairly well with that of nitrate in the northern ECS, implying that nitrate is an important nutrient controlling phytoplankton biomass. The POC:chlorophyll-a ratio was 4~6 times higher in summer than in spring and autumn, presumably because of the high summer phytoplankton death rate caused by nutrient depletion in the surface waters.  相似文献   

Predicting particulate pools of nitrogen,phosphorus and organic carbon in lakes     

Andreas C. Bryhn  Dag O. Hessen  Thorsten Blenckner 《Aquatic Sciences - Research Across Boundaries》2007,69(4):484-494

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Spatial relationships among species, above-ground biomass, N, and P in degraded grasslands in Ordos Plateau, northwestern China   总被引：6，自引：0，他引：6  

X. Cheng  S. An  J. Chen  B. Li  Y. Liu  S. Liu 《Journal of Arid Environments》2007,68(4):652-667

We chose five communities, representing a mild to severe gradient of grassland desertification in a semi-arid area of Ordos Plateau, northwestern China, to explore the spatial relationships among plant species, above-ground biomass (AGB), and plant nutrients (N and P). Community 1 (C1) was dominated by Stipa bungeana; Community 2 (C2) by a mix of S. bungeana and the shrub Artemisia ordosica; Community 3 (C3) by A. ordosica; Community 4 (C4) by a mix of Cynanchum komarovii and C. komorovii; and Community 5 (C5) by C. komorovii. Quantitative methods, including geostatistics, were used to compare community composition, structure, and indicators of ecosystem function (i.e. AGB, plant N and P) in five 16-m² plots. The highest AGB, plant nitrogen (N) and plant phosphorus (P) were found in lightly degraded community C2. With increasing desertification effects from C3 to C5, the AGB, N, and P decreased significantly while plant density remained unchanged. The spatial variations of AGB were higher in shrub-dominated communities (C1 and C5) than in grass-dominated communities (C2–C4). Strong spatial relationships were detected within and among the communities, with stronger relationships between AGB and density than between AGB and species richness. Spatial patterns of plant N and P were different from those of AGB, reflecting different N and P contents of individual plants and different species that can redistribute soil resources in these communities. The AGB was positively correlated with soil nutrients (TOC, TN, TP, and IN), except for soil AP. We concluded that several specific aspects of ecosystem properties were directly associated with the conversion of the grass and shrub “functional types” in these degraded grasslands.  相似文献   

Prescribed fire in a Great Basin sagebrush ecosystem: Dynamics of soil extractable nitrogen and phosphorus   总被引：1，自引：0，他引：1  

B.M. Rau  R.R. Blank  J.C. Chambers  D.W. Johnson   《Journal of Arid Environments》2007,71(4):362-375

Pinyon and juniper have been expanding into sagebrush (Artemisia tridentata) ecosystems since settlement of the Great Basin around 1860. Herbaceous understory vegetation is eliminated as stand densities increase and the potential for catastrophic fires increases. Prescribed fire is increasingly used to remove trees and promote recovery of sagebrush ecosystems. We quantified the effects of prescribed fire, vegetation type, and time following fire on soil KCl extractable nitrogen and NaHCO₃ extractable phosphorus in a pinyon–juniper woodland and its associated sagebrush ecosystem immediately before and for 4 years after a spring prescribed burn. Potassium chloride extractable NH₄⁺ and total inorganic-N increased immediately following prescribed fire, and extractable NO₃⁻ decreased immediately after the burn. In the surface layer (top 8 cm), extractable NH₄⁺ remained elevated compared to the control through year 2 after the burn. By the first fall post-burn extractable NO₃⁻ and total extractable inorganic-N increased and remained elevated over the control through year 3 after the burn in the surface layer. For the entire soil profile (52 cm), the burn had no effect on NH₄⁺, and the effects on total extractable inorganic-N were no longer significant after year 1. However, NO₃⁻ remained elevated over the control through year 2 post-fire for the soil profile. Near surface NaHCO₃ extractable ortho-P increased immediately following fire, and remained elevated through year 2 post-fire. No fire effects were observed for extractable ortho-P in deeper horizons. Our data show that plant available nitrogen can remain elevated for extended periods following prescribed fire. This can influence regrowth and seedling establishment of native plant species, invasion of exotic plant species and, ultimately, site recovery potential.  相似文献