石油烃和营养盐的复合污染对海洋浮游植物的影响Ⅰ. 石油烃对海洋浮游植物吸收营养盐的影响

通过向具有相同营养盐浓度的培养体系中添加不同浓度的石油烃,对中肋骨条藻、赤潮异弯藻、微小亚历山大藻和锥状斯氏藻进行周期性培养,探讨了石油烃对微藻营养盐吸收动力学的影响.结果发现,在开始30min内,微藻对营养盐均有一非耗能的短暂快吸收,随后吸收速率下降并趋于稳定.石油烃对中肋骨条藻和赤潮异弯藻氮、磷的吸收都表现抑制作用,浓度从0.13 mg/L到8.25mg/L的石油烃所呈现的抑制作用基本表现为先减弱后逐渐增强,8.25mg/L浓度的石油烃抑制作用最强.与中肋骨条藻和赤潮异弯藻实验结果不同的是,石油烃对微小亚历山大藻和锥状斯氏藻的氮、磷吸收在低浓度时呈现促进作用,且促进作用的程度随石油烃浓度的增加有先增强后减弱的趋势,在高浓度下促进作用会消失,8.25mg/L的石油烃不表现促进作用.石油烃对微藻营养盐吸收动力学的影响表现出复杂性,这既受石油烃浓度的影响,也与浮游植物的种类有重要关系.     

A nutrient loading budget for Biscayne Bay, Florida

The water quality in Biscayne Bay has been significantly affected by past and continuing coastal and watershed development. The nutrient concentrations in the Bay have been dramatically changed by the conversion of natural creeks and sheet flow freshwater inputs to rapid and episodic canal inputs from the large and rapidly expanding Miami metropolitan area. This study is an evaluation of nutrient loadings to Biscayne Bay for 1994-2002 from canal, atmospheric, and groundwater sources. Dissolved inorganic nitrogen (DIN, as nitrate, nitrite, and ammonium) and total phosphorus (TP) loadings by the canals were influenced by their geographic locations relative to discharge amount, watershed land use, stormwater runoff, and proximity to landfills. Annual budgets showed that canals contributed the bulk of N loading to the bay as 1687.2 metric ton N yr(-1) (88% total load). Direct atmospheric DIN load for Biscayne Bay was only 231.7 ton N yr(-1), based on surface area. Of the canal DIN load, nitrate+nitrite (NO(x)(-)) loading (1294.5 ton N yr(-1)) made up a much greater proportion than that of ammonium (NH(4)(+), 392.6 ton N yr(-1)). In the urbanized north and central Bay, canal DIN load was evenly split between NO(x)(-) and NH(4)(+). However, in the south, 95% of the DIN load was in the form of NO(x)(-), reflecting the more agricultural land use. Contrary to N, canals contributed the only 66% of P load to the bay (27.5 ton P yr(-1)). Atmospheric TP load was 14 ton Pyr(-1). In the north, canal P load dominated the budget while in the south, atmospheric load was almost double canal load. Groundwater inputs, estimated only for the south Bay, represented an important source of N and P in this zone. Groundwater input of N (141 ton N yr(-1)) was about equal to atmospheric load, while P load (5.9 ton P yr(-1)) was about equal to canal load.     

Experimental evidence for an effect of early-diagenetic interaction between labile and refractory marine sedimentary organic matter on nitrogen dynamics

In most natural sedimentary systems labile and refractory organic material (OM) occur concomitantly. Little, however, is known on how different kinds of OM interact and how such interactions affect early diagenesis in sediments. In a simple sediment experiment, we investigated how interactions of OM substrates of different degradability affect benthic nitrogen (N) dynamics. Temporal evolution of a set of selected biogeochemical parameters was monitored in sandy sediment over 116 days in three experimental set-ups spiked with labile OM (tissue of Mytilus edulis), refractory OM (mostly aged Zostera marina and macroalgae), and a 1:1 mixture of labile and refractory OM. The initial amounts of particulate organic carbon (POC) were identical in the three set-ups. To check for non-linear interactions between labile and refractory OM, the evolution of the mixture system was compared with the evolution of the simple sum of the labile and refractory systems, divided by two. The sum system is the experimental control where labile and refractory OM are virtually combined but not allowed to interact. During the first 30 days there was evidence for net dissolved-inorganic-nitrogen (DIN) production followed by net DIN consumption. (Here ‘DIN’ is the sum of ammonium, nitrite and nitrate.) After  30 days a quasi steady state was reached. Non-linear interactions between the two types of OM were reflected by three main differences between the early-diagenetic evolutions of nitrogen dynamics of the mixture and sum (control) systems: (1) In the mixture system the phases of net DIN production and consumption commenced more rapidly and were more intense. (2) The mixture system was shifted towards a more oxidised state of DIN products [as indicated by increased (nitrite + nitrate)/(ammonium) ratios]. (3) There was some evidence that more OM, POC and particulate nitrogen were preserved in the mixture system. That is, in the mixture system more particulate OM was preserved while a higher proportion of the decomposed particulate N was converted into inorganic N. It can be concluded that during the first days and weeks of early diagenesis the magnitude and composition of the flux of decompositional dissolved N-compounds from sediments into the overlying water was influenced by non-linear interactions of OM substrates of different degradability. Given these experimental results it is likely that the relative spatial distributions of OM of differing degradability in sediments control the magnitude and composition of the return flux of dissolved N-bearing compounds from sediments into the overlying water column.     

利用叶绿素荧光方法检测东海浮游植物的营养盐限制

2011年6月10日-6月27日调查了东海赤潮高发区PSⅡ最大光化学量子产量(Fv/Fm)的平面分布,发现在东海赤潮高发区Fv/Fm的平面分布与叶绿素的平面分布较为一致。利用现场营养盐加富培养的方法,通过检测添加不同的营养元素后Fv/Fm的变化,研究了2个调查站位浮游植物受何种营养盐的限制。结果表明,对于浮游植物来说,东海DH2-3站和DH6-2站浮游植物的生长受到N潜在限制。通过Fv/Fm的变化,可以反映出藻细胞实际的生理活性,从而更真实的反映营养盐对浮游植物的作用。     

全安盆地水文地质特征及热水成因分析

在简要分析全安盆地水文地质特征、地下水赋存条件及划分地下水类型基础上,对盆地西部周地—暖水塘地区地下热水形成原因、赋存环境进行研究,认为多期次构造运动形成的断裂、裂隙沟通深部地下热水是盆地热水来源的主要原因;采取地下热水样品并开展氢氧稳定同位素、逸出气体、水化学成份测试,认为地下热水由大气降水补给,长期水动态观测结果也显示大气降水与地下热水关系较密切。     

Converting tropical rain forest to forest plantation in sabah,malaysia. Part I. Dynamics and net losses of nutrients in control catchment streams

Streamwatcr chemistry was monitored for five years in six streams in a paired catchment experiment in Mendolong, Sabah, Malaysia, including controls in rain forest and secondary vegetation after the [Borneo fire] of 1982–3 and comparing the effects of different ways of establishing forest plantations with Acacia mangium. Three catchments were covered with selectively logged lowland hill dipterocarp forest (W4-W6) and three (W1-W3) with secondary vegetation after forest fires. The control catchments, W3 and W6 reported in this paper, had no treatments applied. Reference monitoring at all streams was for 25 months and the total period of study reported here is 64 months. The soils in the catchments were mainly Orthic Acrisol in W3 and Gleyic Podsol in W6 and a mix of both soil types in the other catchments. Element baseflow concentrations were generally low and not significantly different from stormflow concentrations for all streams during the reference period. Concentrations were also generally consistently low for the two control streams during the whole period of measurement. Chemical inputs as wet deposition were low as a result of a high input from local convection. The rain forest on the Podsol had a tight nutrient circulation indicated by small net losses of macronutrients. The Podsol was found to have poorer conditions for soil mineralization and more surficial runoff, resulting in higher loads of S, C and N in the organic phases, with higher organic C/N ratio, in the discharge. Nitrogen was found to accumulate in both catchments. An almost double accumulation of N in W3 was attributed to a larger biomass accumulation continuing after the forest fire 3–8 years earlier. On the other hand, the Acrisol in W3 had much larger net losses of S, Si, K, Ca, Mg and Na. Most of differences could be attributed to differences in weathering between the soils and local mineralogical differences.     

The Geochemistry of Lake Joyce, McMurdo Dry Valleys, Antarctica

Lake Joyce is one of the least studied lakes of the McMurdo Dry Valleys. Similar to other lakes in this region, Lake Joyce is a closed-basin, permanently ice-covered, meromictic lake. We present here a detailed investigation of major ions, nutrients, and dissolved trace elements for Lake Joyce. Specifically, we investigate the role of iron and manganese oxides and hydrous oxides in trace metal cycling.Lake Joyce is characterized by fresh, oxic waters overlying an anoxic brine, primarily Na–Cl. Surface waters have a maximum nitrate concentration of 26M with a molar dissolved inorganic nitrogen to phosphorus ratio of 477. The supply of nitrogen is attributed to atmospheric deposition, possibly from polar stratospheric clouds. Dissolved phosphorus is scavenged by hydrous iron oxides. The pH is highest (10.15) just beneath the 7-m thick ice cover and decreases to a minimum of 7.29 in the redox transition zone. Dissolved Al exceeds 8M in surface waters, and appears to be controlled by equilibrium with gibbsite. In contrast, concentrations of other trace elements in surface waters are quite low (e.g., 5.4nM Cu, 0.19nM Co, <20pM La). Dissolved Fe, Mn, Ni and Cd were below our detection limits of 13 nM, 1. 8 nM, 4.7 nM and 15pM (respectively) in surface waters. There was a 6-m vertical separation in the onset of Mn and Fe reduction, with dissolved Mn appearing higher in the water column than Fe. Based on thermodynamic calculations, dissolved Mn appears to be controlled by equilibrium with hausmannite (Mn3O4). Co tracks the Mn profile closely, suggesting Co(III) is bound in the lattice of Mn oxides, whereas the Ce profile is similar, yet the Ce anomaly suggests oxidative scavenging of Ce. Release of Cu, Ni, Cd and trivalent REE appears to be controlled by pH-induced desorption from Fe and Mn oxides, although Cu (and perhaps Ni) may be scavenged by organic matter in surface waters.     

Mercury cycling during acid rain recovery at the forested Lesní potok catchment,Czech Republic

From 2011 to 2019, mercury (Hg) stores and fluxes were studied in the small forested catchment Lesní potok (LES) in the central Czech Republic using the watershed mass balance approach together with internal measurements. Mean input fluxes of Hg via open bulk deposition, beech throughfall and spruce throughfall during the periodwere 2.9, 3.9 and 7.6 μg m⁻² year⁻¹, respectively. These values were considerably lower than corresponding deposition Hg fluxes reported in the early years of the 21st century from catchments in Germany. Current bulk precipitation inputs at unimpacted Czech mountainous sites were lower than those in Germany. The largest Hg inputs to the catchment were via litterfall, averaging 22.6 and 17.8 μg m⁻² year⁻¹ for beech and spruce stands. The average Hg input, based on the sum of mean litterfall and throughfall deposition, was 23.0 μg m⁻² year⁻¹, compared to the estimated Hg output in runoff of 0.5 μg m⁻² year⁻¹, which is low compared to other reported values. Thus, only ~2% of Hg input is exported in stream runoff. Stream water Hg was only weakly related to dissolved organic carbon (DOC) but both concentrations were positively correlated with water temperature. The estimated total soil Hg pool averaged 47.5 mg m⁻², only 4% of which was in the O-horizon. Thus Hg in the O-horizon pool represents 72 years of deposition at the current input flux and 3800 years of export at the current runoff flux. Age-dating by ¹⁴C suggested that organic soil contains Hg from recent deposition, while mineral soil at 40–80 cm depth contained 4400-year old carbon, suggesting the soil had accumulated atmospheric Hg inputs through millennia to reach the highest soil Hg pool of the soil profile. These findings suggest that industrial era intensification of the Hg cycle is superimposed on a slower-paced Hg cycle during most of the Holocene.     

长江冲淡水的扩展及其营养盐的输运

本文根据长江口及其邻近海域硝酸盐和硅酸盐的平面分布特征,研究得出,除冬季外,长江冲淡水中的营养盐同时向两个方向输送,一、向北或东北输入南黄海西南部;二、向南或东南输入东海。据此提出“长江冲淡水双向扩展”的观点,即长江冲淡水先顺河口走向朝东南方向流动,到达口门处分成两部分（冬季除外）,一部分穿过杭州湾口及舟山群岛一带沿岸南下,或自长江口向东南方向扩展;另一部分则左转向北或东北,进入南黄海西南部。南、北两股冲淡水的水量大小及其比例,因不同季节而异。     

Seasonal variation in the biogeochemical cycling of seston in Grand Traverse Bay, Lake Michigan

This study describes the biogeochemical cycling of seston in Grand Traverse Bay, Lake Michigan. Seston was characterized by carbon and nitrogen elemental and isotopic abundances. Fluorescence, temperature, light transmittance, and concentrations of dissolved inorganic nitrogen were also determined. PCBs were analyzed from surface (10 m) seston and ΣPCB was calculated by summing all of the congeners quantified in each sample. The vertical and seasonal trends in the δ¹³C values of seston exhibited a broad range from −30.7 to −23.9‰. Low δ¹³C values that occur concurrently with a peak in fluorescence below the thermocline reflect uptake of ¹³C depleted respiratory CO₂ and/or the accumulation of ¹³C depleted lipids by phytoplankton. High δ¹³C values late in the season likely result from a reduction in photosynthetic fractionation associated with a decrease in the CO₂ pool. Seasonal δ¹⁵N values of seston were high in the spring and declined through August. The δ¹⁵N values of seston reflect a balance between fractionation during assimilation of NH₄⁺ or NO₃⁻ and degradative processes. The seston ΣPCB and fluorescence were both high in the spring and subsequently declined, suggesting that the concentrations of PCBs in seston were associated with labile material derived from primary productivity. The strong seasonal trends in the organic geochemical characteristics of seston and concentrations of PCBs emphasize the complex nature of particle cycling in aquatic environments.