两种白刺叶片及沙堆土壤化学计量学特征的比较

在植物叶片氮、磷化学计量学研究中,氮磷比常作为判断土壤养分限制性的指标,其适用范围从海洋、湖泊等水生生态系统扩展到陆地生态系统。以生长在民勤绿洲的毛瓣白刺(Nitraria praevisa)和唐古特白刺(N. tangutorun)为研究对象,分别测定叶片N、P含量以及沙堆各层土壤有机质、N、P含量,以探讨两种白刺叶片及其沙堆土壤化学计量学特征的关系。研究结果表明:①白刺叶片的N、P含量之间存在显著的正相关关系;②两种白刺沙堆各项土壤养分指标差异极显著(P<0.01);③毛瓣白刺沙堆土壤的N含量在0～20 cm土层存在富集现象,唐古特白刺沙堆土壤的有机质、N、P含量在20～40 cm土层存在富集现象;④在水分为最主要的限制性因子的荒漠生态系统中,能否以叶片N∶P作为判定营养元素限制性的标准,值得进一步探讨。     

Variations in the depth distribution of phosphorus in soil profiles and implications for model-based catchment-scale predictions of phosphorus delivery to surface waters

The PSYCHIC process-based model for predicting sediment and phosphorus (P) transfer within catchments uses spatial data on soil-P derived from the National Soil Inventory (NSI) data set. These soil-P values are based on bulked 0–15 cm depth and do not account for variations in soil-P with depth. We describe the depth distribution of soil-P (total and Olsen) in grassland and arable soils for the dominant soil types in the two PSYCHIC study catchments: the Avon and the Wye, UK. There were clear variations in soil-P (particularly Olsen-P) concentrations with depth in untilled grassland soils while concentrations of total-P were broadly constant within the plough layer of arable soils. Concentrations of Olsen-P in arable soils, however, exhibited maximum values near the soil surface reflecting surface applications of fertilisers and manures between consecutive ploughing events. When the soil-P concentrations for the surface soil (0–5 cm average) were compared to both the profile-averaged (0–15 cm) and the NSI (0–15 cm) values, those for the surface soil were considerably greater than those for the average 0–15 cm depth. Modelled estimates of P loss using the depth-weighted average soil-P concentrations for the 0–5 cm depth layer were up to 14% greater than those based on the NSI data set due to the preferential accumulation of P at the soil surface. These findings have important implications for the use of soil-P data (and other data) in models to predict P losses from land to water and the interpretation of these predictions for river basin management.     

新疆准噶尔盆地典型荒漠区不同景观植被对土壤养分的影响

在群落演替的不同阶段,土壤与植被之间存在不同的互动关系。在新疆准噶尔盆地南缘,选择荒漠-绿洲交错区、沙漠边缘、沙漠腹地典型景观类型取样,监测不同景观条件下土壤水分、土壤有机质、全氮、全磷和植被盖度。结果表明,不同景观植被盖度、土壤水分、土壤养分含量存在显著的差异性(P0.5)。土壤水分含量、植被盖度、土壤养分含量表现为荒漠-绿洲交错区沙漠边缘沙漠腹地的变化趋势;土壤含水量由荒漠-绿洲交错带10.4%递减到沙漠边缘5.8%、沙漠腹地3.5%;植被盖度、土壤养分含量随土壤类型由荒漠灰钙土向风沙土过渡,呈现显著的下降趋势。在相同土壤属性情况下,植被盖度与土壤有机质、土壤全氮之间存在显著的线性正相关关系,表明不同区域内植被在一定程度上影响土壤养分的积累。     

河岸带土壤磷素空间分布及其对水文过程响应

野外观测太湖地区典型农业河岸带——浯溪荡河岸带土壤总磷（TP）和溶解性总磷（DTP）含量以及当地降雨量、河水水位和地下水水位,探讨了丰水年条件下该河岸带土壤TP和DTP的空间分布特征以及水文过程对其空间分布的影响。结果表明:①在水平方向上,土壤TP和DTP含量从远岸向近岸均呈现先减少后增加的变化趋势;在深度方向上,各断面TP和DTP含量随土层深度的增加均呈减少的变化趋势。②不同月份河水水位均低于地下水水位,地下水补给河水。河水水位和地下水水位随时间的变化规律与降雨量的相似,但具有一定的滞后性。③降雨是土壤水分运动的主要驱动力,降雨、河水水位以及地下水水位对河岸带土壤磷素空间分布的影响显著不同。     

桑沟湾磷循环

The phosphorus cycle is studied during 2013–2014 in the Sanggou Bay(SGB), which is a typical aquaculture area in northern China. The forms of measured phosphorus include dissolved inorganic phosphorus(DIP), dissolved organic phosphorus(DOP), particulate inorganic phosphorus(PIP), and particulate organic phosphorus(POP).DIP and PIP are the major forms of total dissolved phosphorus(TDP) and total particulate phosphorus(TPP),representing 51%–75% and 53%–80%, respectively. The concentrations and distributions of phosphorus forms vary among seasons relative to aquaculture cycles, fluvial input, and hydrodynamic conditions. In autumn the concentration of DIP is significantly higher than in other seasons(P0.01), and higher concentrations are found in the west of the bay. In winter and spring the phosphorus concentrations are higher in the east of the bay than in the west. In summer, the distributions of phosphorus forms are uniform. A preliminary phosphorus budget is developed, and shows that SGB is a net sink of phosphorus. A total of 1.80×10~7 mol/a phosphorus is transported into the bay. The Yellow Sea is the major source of net input of phosphorus(61%), followed by submarine groundwater discharge(SGD)(27%), river input(11%), and atmospheric deposition(1%). The main phosphorus sink is the harvest of seaweeds(Saccharina japonica and Gracilaria lemaneiformis), bivalves(Chlamys farreri),and oysters(Crassostrea gigas), accounting for a total of 1.12×10~7 mol/a. Burial of phosphorus in sediment is another important sink, accounting for 7.00×10~6 mol/a. Biodeposition by bivalves is the major source of phosphorus in sediment, accounting for 54% of the total.     

准噶尔盆地灰漠土无机磷形态及磷吸附特性研究

选择新疆准噶尔盆地灰漠土作为研究对象,通过测定灰漠土中不同形态的无机磷素含量并进行土壤磷素等温吸附实验,研究灰漠土中各形态无机磷素的有效性和土壤磷吸附特征。结果表明,灰漠土中无机磷形态主要是Ca-P,占全磷含量75%以上,且以Ca₁₀-P形式为主,其次为Ca₈-P和Ca₂-P,无机磷中Al-P、Fe-P和O-P含量较少。全剖面中随着土层深度增加,Ca₂-P、Ca₈-P和Al-P占全磷总量的比例减少,Ca₁₀-P占全磷总量则有所增加,0~20 cm土层全磷和Olsen-P含量最高,分别平均为926 mg·kg^-1和51.54 mg·kg^-1。统计分析表明Ca₂-P、Al-P是最有效的磷源,Ca₈-P和Fe-P是第二有效磷源,O-P和Ca₁₀-P则是作物的潜在磷源。利用Langmuir方程拟合灰漠土的磷等温吸附曲线,得出土壤最大吸磷量（Xm）为957±629 mg·kg^-1,吸附参数（K）为149.285±89.225;灰漠土的粘粒含量对Xm影响最大,其次是有机质,pH值影响最小。     

遥感技术在河口颗粒态总磷分布及扩散研究中的应用初探

以美国SeaStar卫星装载的SeaWiFS海洋水色遥感传感器作为遥感数据源,实测了光谱、海表温度、悬浮物含量、透明度、叶绿素浓度、颗粒态总磷含量等,建立了传感器悬浮物含量和颗粒态总磷含量的遥感信息提取模式,结果表明:(1)利用遥感技术估算的海水悬浮物的平均相对偏差为18.1%;(2)悬浮物在遥感图象上的分布和扩散趋势与实际吻合,并且在一定程度上反映了区域内海流运移路径;(3)颗粒态总磷含量在长江河口和杭州湾附近海域较高,由近岸向远岸迅速降低,与实际分布相符;(4)模型主要适用于河口等悬浮物含量高的Ⅱ类水休,对于以浮游植物为主的Ⅰ类水体应另外建立模式.     

WA-PLS diatom-based pH, TP and DOC inference models from 42 lakes in the Abitibi clay belt area (Québec, Canada)

The relationship between surficial sediment diatom species and measured environmental variables was explored in lakes from the Abitibi region of western Quebec. Diatom assemblages in 42 lakes were identified and their relationship with measured environmental variables was examined using multivariate statistical methods. Canonical correspondence analysis with forward selection and Monte Carlo permutation tests revealed that the three environmental variables pH, TP and DOC each accounted for statistically significant fractions of the variation in diatom taxa. A training set with 164 modern diatom taxa was used to derive transfer functions for lake-water pH, TP and DOC using weighted-averaging-partial-least-squares (WA-PLS) techniques. The models were developed to infer lake water pH, TP and DOC within the ranges 4–8 for pH, 2.75–30.0 g l^–1 for TP, and 2.9–18.5 mg l^–1 for DOC. These quantitative inference models may now be used to help identify and estimate the effects of natural disturbances on the biogeochemistry of Abitibi lakes during their historical development.     

Retrospective analysis of the impacts of major hurricanes on sediments in the lower Everglades and Florida Bay

A record of the impacts of major hurricanes on sediment stratigraphy and composition in subtropical ecosystems has been preserved in the lower Everglades and Florida Bay. These impacts were observed in discontinuous layers of sediment that were identified from high-resolution, vertical profiles of excess ²¹⁰Pb and ¹³⁷Cs. Discontinuities were found at different geographic locations and at two to three different depths in the sediment column; however, the layers were each deposited within time periods that corresponded with the passing of category 3–5 hurricanes during 1960, 1948 and 1935. A simple mass balance model for excess ²¹⁰Pb was used to show net changes of ±20–100% in excess ²¹⁰Pb inventory that resulted from sediment disturbances of <1 to >22 cm. Abrupt shifts in sediment composition were often observed in hurricane-impacted layers. Ratios of organic (C/P) were four- to fivefold higher than normal in post-hurricane layers of sediment at open bay sites. These layers are phosphorus poor and seem to reflect preferential decomposition of organic P relative to organic C in association with hurricanes. The net effect is for major hurricanes to redistribute sediment, organic matter and nutrients.This revised version was published online in July 2003.     

氮源、磷源及重金属离子对绿色巴夫藻生长的影响

研究了不同氮源、磷盐、不同氮磷比以及培养液中3种重金属离子含量对绿色巴夫藻(Pavlovaviridis)生长的影响。结果表明:无机氮、有机氮共同提供氮源,以及磷酸二氢钠提供磷源,氮磷比5∶1时,绿色巴夫藻生长速度最快;铅、锌、铜离子可不同程度地影响绿色巴夫藻的生长,三者的毒性依次增大,三者的96hEC50分别为25.700、7 .079和1 469mg/L。