氮、磷对两种微藻吸附与吸收镍的影响   总被引：4，自引：0，他引：4  

黄旭光  王大志  王明华  洪华生 《海洋与湖沼》2006,37(2):105-110

采用放射性同位素示踪的方法,研究了大量营养盐氮和磷添加对两种微藻:东海原甲藻(Prorocentrum donghaienseLu)和中肋骨条藻(Skeletonema costatum)吸附和吸收重金属镍的影响。结果表明,在短时间(2h)的培养实验中,大量营养盐的添加影响了藻类对重金属的吸附和吸收速率,但氮、磷浓度的增加对藻类吸附和吸收镍的影响有所差异:硝酸盐浓度的添加促进了藻类对镍的吸附和吸收,磷浓度的添加促进了两种藻类对镍的吸附,但对藻类吸收镍的影响不大。在未添加营养盐的条件下,东海原甲藻对镍的吸附量要高于硝酸盐添加组但吸收量则较低,而中肋骨条藻的吸附量和吸收量均较硝酸盐添加组低。当尿素为氮源时,尿素促进了藻类对镍的吸收,其吸收量为同一浓度硝酸盐的1·2倍。本研究结果证明,近海富营养化特别是氮浓度的增加会影响浮游植物对微量金属的吸收,进而可能会影响到金属在整个海洋食物链中的传递。  相似文献   

温、盐度及营养盐对不同藻株塔玛亚历山大藻生长的影响   总被引：1，自引：0，他引：1  

方琦  顾海峰  蓝东兆  黄元辉 《海洋通报》2006,25(6):20-25

利用2001年11月至2003年2月从长江口、闽江口和北部湾水域表层沉积物中分离的休眠孢囊,萌发获得三株塔玛亚历山大藻,并研究了温度、盐度、营养盐对它们生长的影响。实验结果表明,来源于三个不同海区的藻株在水温32℃的条件下均无法存活,温度对长江口藻株(ATDH01)及广西北部湾藻株(ATGX02)的生长有极显著影响(P<0.01),而对闽江口藻株(ATMJ02)的生长无显著影响(P>0.05)。不同海区的藻株,其生长特性有明显差异,ATDH01藻株最适生长温度为24℃,最适生长盐度为30,且在盐度15和35仍有较高的生长率;而ATMJ02藻株及ATGX02藻株最适生长温度分别为24℃和20℃,最适生长盐度范围为20～30,盐度超出此范围生长率明显降低。ATDH01藻株的生长繁殖能力最强。营养盐对三个不同海区藻株生长的影响基本一致,在低P(1.2μmol/L)组中,三株藻的指数生长期较短,细胞密度明显的低于f/2组;而在低N(44μmol/L)组中,虽然在培养初期,三株藻的细胞生长明显快于f/2组,但在生长后期由于氮的限制,最终细胞密度仍低于f/2组。  相似文献   

Seasonal and interannual variability in phytoplankton and nutrient dynamics along Line P in the NE subarctic Pacific     

M. Angelica Peña  Diana E. Varela 《Progress in Oceanography》2007,75(2):200-222

We analysed mixed-layer seasonal and interannual variability in phytoplankton biomass and macronutrient (NO₃ and Si(OH)₄) concentrations from three decades of observations, and nitrogen uptake rates from the 1990s along Line P in the NE subarctic Pacific. Chlorophyll a concentrations near 0.35 mg m⁻³ were observed year-round along Line P except at the nearshore station (P4) where chlorophyll a concentrations in spring were on average 2.4 times the winter values. In contrast, the temporal variability in carbon-to-chlorophyll ratios at the two main end members of Line P (P4 and OSP) was high. Large seasonal and interannual variability in NO₃ and Si(OH)₄ concentration were observed along Line P. Highest upper mixed-layer (top 15 m) nutrient concentrations occurred on the continental shelf in late summer and early fall due to seasonal coastal upwelling. Beyond the shelf, maximum nutrient concentrations increased gradually offshore, and were highest in late winter and early spring due to mixing by winter storms. Interannual variations in upper mixed-layer nutrient concentrations beyond the shelf (>128°W) were correlated with E-W winds and the PDO since 1988 but were not correlated with either climate index between 1973 and 1981. Despite differences in nutrient concentration, nutrient utilization (ΔNO₃ and ΔSi(OH)₄) during the growing season were about 7.5 μM at all offshore stations. Variations in ΔNO₃ were correlated with those of ΔSi(OH)₄. The annual cycle of absolute NO₃ uptake (ρNO₃) and NH₄ uptake (ρNH₄) rates by phytoplankton in the upper mixed-layer showed a weak increasing trend from winter to spring/summer for the period 1992-1997. Rates were more variable at the nearshore station (P4). Rates of ρNO₃ were low along the entire line despite abundant NO₃ and low iron (Fe), at the offshore portion of Line P and sufficient Fe at the nearshore station (P4). As a result, new production contributed on average to only 32 ± 15% of the total nitrogen (N) uptake along Line P. NO₃ utilization in the NE subarctic Pacific is probably controlled by a combination of environmental variables, including Fe, light and ambient NH₄ levels. Elevated ambient NH₄ concentrations seem to decrease the rates of new production (and f-ratios) in surface waters of the oceanic subarctic NE Pacific. Contrary to expectation, phytoplankton biomass, nutrient utilization (ΔNO₃ and ΔSi(OH)₄), and nitrogen uptake (ρNO₃ + ρNH₄) varied relatively little along Line P, despite significant differences in the factors controlling phytoplankton composition assemblages and production. Future studies would benefit from including other variables, especially light limitation, to improve our understanding of the seasonal and interannual variability in phytoplankton biomass and nutrients in this region.  相似文献   

Nutrient irrigation of the North Atlantic   总被引：2，自引：1，他引：2  

J.L. Pelegrí  A. Marrero-Díaz  A.W. Ratsimandresy 《Progress in Oceanography》2006,70(2-4):366

The North Atlantic, as all major oceans, has a remarkable duality in primary production, manifested by the existence of well-defined high and low mean primary production regions. The largest region is the North Atlantic Subtropical Gyre (NASTG), an anticyclone characterized by bowl shaped isopycnals and low production. The NASTG is surrounded at its margins by smaller cyclonic high-production regions, where these isopycnals approach the sea surface. The most extensive cyclonic regions are those at the latitudinal extremes, i.e. the subpolar and tropical oceans, though smaller ones do occur at the zonal boundaries. In this article we review historical data and present new analyses of climatological data and a selected number of hydrographic cruises in the western/northwestern and eastern/southeastern boundaries of the NASTG, with the objective of investigating the importance of upward epipycnal advection of nutrient-rich subsurface layers (irrigation) in maintaining high primary production in the euphotic layers. In the North Atlantic Subpolar Gyre (NASPG) irrigation implies intergyre exchange caused by the outcropping extension of the Gulf Stream (GS), following the formation of the deep winter mixed-layer. In the eastern boundary of the NASTG irrigation is attained through a permanent upwelling cell, which feeds the Canary Upwelling Current (CUC). In the southeastern corner irrigation occurs in fall, when the Guinea Dome (GD) is reinforced, and in winter, when the CUC reaches its southernmost extension. Other characteristics of the north/south extension of the GS/CUC are the seasonal nutrient replenishing of subsurface layers (spring restratification of NASPG and winter relaxation of the GD) and the maintenance of high levels of diapycnal mixing during the last phase of nutrient transfer to the euphotic layers. Off the Mid-Atlantic Bight the GS transports a total of about 700 kmol s⁻¹ of nitrate, with almost 100 kmol s⁻¹ carried in the surface (σ_θ < 26.8) layers and some 350 kmol s⁻¹ in the intermediate (26.8 < σ_θ < 27.5) layers. A box model suggests that north of Cape Hatteras most surface and upper-thermocline nitrates are used to sustain the high levels of primary production in the NASPG. Off Cape Blanc there is winter along-shore convergence of order 10 kmol s⁻¹ of nitrate in the near-surface layers (possibly larger in summer), with only a small fraction used to sustain local primary production in the coastal upwelling band and the remainder carried to the interior ocean. Nutrients and biomass exported from these cyclonic regions may account for the concentration levels observed within the NASTG.  相似文献   

南沙群岛海域沉积物-海水界面间营养物质的扩散通量   总被引：25，自引：1，他引：25  

宋金明  李鹏程 《海洋科学》1996,20(5):43-50

主要研究了南沙群岛海域泻湖及礁外沉积物间隙水生态系中的营养 组份 ＮＯ３－Ｎ， ＮＯ２－Ｎ， ＮＨ４－Ｎ， ＰＯ４－Ｐ， ＳｉＯ３－Ｓｉ及其在沉积物一海水界面间扩散转 移通量，结果表明：（１）该海域间隙水中营养组份的浓度较高，∑Ｎ／Ｐ礁外间 隙水高于泻湖间隙水，相对而言，泻湖间隙水中缺氮，礁外间隙水中缺磷，礁外 间隙水中营养组份的垂直分布各异。（２）该海域沉积物活性明显高于东中国 海，沉积物中大量营养组份向上覆海水扩散转移，Ｈ４ＳｉＯ４是礁外界面扩散是最 大的组份，而在泻湖中ＮＯ３－或ＮＨ４＋是最大扩散量的组份，礁外界面Ｈ４ＳｉＯ４， ＮＯ３－扩散大于泻湖，这些扩散转移特征由组份本身的性质与环境特性决定； （３）该海域水温高是造成间隙水中营养组份大量产出并向上覆海水扩散转移 的主要原因，温度高，沉积物释放出营养组份的表现活化能降低，沉积物的活 性增强，从而释放扩散出大量的营养组份。  相似文献   

渤海春季营养盐限制的现场实验   总被引：22，自引：0，他引：22  

邹立  张经 《海洋与湖沼》2001,32(6):672-678

1999年4－5月，在现场条件下对天然水体中浮游植物以外加营养盐受控培养的方式，研究和探讨春季渤海中部、莱州湾和渤海海峡3个海区的浮游植物生长的营养盐限制问题。结果表明，在莱州湾附近浮游植物生长受到显著的磷限制；尽管水体中硅酸盐浓度较历史水平大大降低，并且实验进行时硅藻为优势种，但是硅酸盐尚不成为限制因子；渤海中部不存在营养盐的限制问题，营养盐浓度和结构相对适宜；渤海海峡也不存在营养盐的限制问题，但是溶解无机氮的相对含量略低。  相似文献   

冲绳海槽末次冰期、全新世沉积物化学元素分布特征   总被引：1，自引：0，他引：1  

李凤业  何丽娟  史玉兰 《海洋科学》1996,20(5):55-59

根据测定冲绳海槽０８０、０８２两岩芯中放射性同位素和化学元素的垂种布，基于＾２３０Ｔｈ／＾２３２Ｔｈ放射性活度比值，确定了末次冰期和全新世之间确切地层年代。测得资料表明，在全新世和晚更新世期间沉积物中元素丰度有很大的变化，反映了冲绳海槽在不同历史时期沉积环境的变迁和物质来源的差异。  相似文献   

Flux of nutrients in the Gulf of California: Geostrophic approach     

Hctor Bustos-Serrano  Rubn Castro-Valdez 《Marine Chemistry》2006,99(1-4):210

Continental margins exert a strong influence on global biogeochemical cycles; however there have been relatively few attempts to quantify either the magnitude or nature of temporal variability in material fluxes. At present here are no reports on nutrient fluxes at the mouth of the Gulf of California (GC) so further information is needed to provide estimated values from direct measurements. From 1995–1999 during five cruises covering all seasons, seawater samples were collected and measured the nutrient content from the surface to the bottom (some deeper than 2500 m) from a repeated hydrographic sections at the mouth of the GC. This chemical and physical database is unique because it covers an area with important biogeochemical signs, which has been detected as one of the highest in primary productivity of the world oceans. These sections are perpendicular to the coastlines of the Mexican states of Baja California Sur (BCS) and Sinaloa. In this section, the most dynamic area was the surface waters in February 1999 with strong geostrophic currents and temperatures of 20 ± 1.5 °C; salinity 35.091 ± 0.156; pH 8.16 ± 0.13; phosphate 0.85 ± 0.42 μM, nitrate + nitrite 2.35 ± 2.94 μM, and ammonia 2.00 ± 1.25 μM (average ± standard deviation).Geostrophic velocities were computed from high-resolution CTD sections across the entrance to the GC. During winter and spring, the outflow occurred near BCS and the inflow occurred either through the center of the section and/or along the Sinaloa coast. Both inflow and outflow cores were 45 km wide and extended deeper than 700 m. Summer and fall showed a complex pattern, alternating cores of inflow and outflow but with inflow along Sinaloa on all cruises. The maximum flow into the Gulf occurs during May in the center of the section while outflow was concentrated along BCS. Mascarenhas et al. [Mascarenhas, A., Castro, R., Collins, C.A., Durazo, R., 2004. Seasonal variation of geostrophic velocity and heat flux at the entrance to the Gulf of California, Mexico. Journal Geophysical Research, 2124.] calculated the section mean geostrophic velocity that was composed of two alternating cores of inflow and outflow. The two cores that were adjacent to either coast were broader and contained the highest inflow (0.40 m s^− 1) and outflow (− 0.25 m s^− 1) velocities, supporting the general idea of inflow along the Sinaloa and an outflow along BCS.The highest nutrient fluxes occur during El Niño conditions in November 1997 with outflows as high as 54.5 Tg yr^− 1 for Phosphate, 43.0 Tg yr^− 1 for Nitrate and 31.7 Tg yr^− 1 for Ammonia, this values were at least three times higher than in February 1999.  相似文献   

Disparate history of transgressing planetary boundaries for nutrients     

《Global Environmental Change》2023

The activation of nitrogen and phosphorus for food production has caused the transgression of the safe operating space of the Earth system. However, countries differ in the use of their fair share of global nutrient activation, causing a disparity that has severe implications for the environment, land degradation and food security. Both the impact on Earth system processes as well as productivity gains and losses and the consequent socio-economic impacts depend on past use. Therefore, in this study, we examined how the activation of nitrogen and phosphorus for food production in relation to countries’ fair shares has evolved globally. The first transgressions of the planetary boundaries occurred in 1970 and 1964 for nitrogen and phosphorus, respectively. Since then, activation has increased 160% and 200%, respectively. Further, notable differences were observed between countries, in which high-income regions such as western Europe and North America had the highest cumulative transgression and sub-Saharan Africa and Oceania had the greatest deficit relative to their fair shares. The main driver for transgression was economic growth rather than population growth or the relatively recent fertiliser subsidies. Although the use of fertilisers has decreased in areas with previous high use, past usage will slow down the effects of fertiliser reductions on ecosystem recovery and maintain a legacy of inequality. Consequently, in addition to reductions in nitrogen and phosphorus activation, recycling accumulated nutrients to regions operating below their fair shares should be explored and economically enabled in order to secure Earth system functioning while eradicating hunger.  相似文献   

Drainage and nutrient attenuation in a riparian interception-wetland: southern Minnesota,USA     

Joe Magner  Scott Alexander 《Environmental Geology》2008,54(7):1367-1376

Riparian wetlands have multiple source waters that require understanding to effectively manage water quantity and quality. Source waters were determined in an interception-wetland located a relatively flat clayey till terrain in southern Minnesota. Data loggers were used to measure precipitation, water stage from monitoring wells and a tile-drain outlet. Over 70 oxygen (δ¹⁸O), hydrogen (δD) and geochemical water samples were collected from seven locations over different seasons (9 events) from 1996 to 1999. Results indicate the dominant source water input to the wetland was drained shallow groundwater beneath intensively managed cropland (P = 0.000). Evapotranspiration was the dominant export pathway. Nitrate–nitrogen (NO₃-N) concentrations significantly decreased (P = 0.000) in the cattail-willow portion of the wetland. Total phosphorous (TP) concentrations were relatively high in the grass portion of the wetland (673 ± 549 μg L⁻¹), and relatively low in the cattail-willow portion of the wetland (139 ± 85 μg L⁻¹) because source waters were low in TP. Overall, the interception-wetland design limited out-of-bank flooding, yet allowed sufficient gradient between the cropland and the wetland outlet to minimize potential crop damage and provide hydraulic storage for nutrient attenuation.  相似文献