Diatom-based dissolved inorganic nitrogen reconstruction in the Changjiang River estuary and its adjacent areas

A five-component weighted average partial least squares(WA-PLS)calibration model was developed by analysing diatom assemblages in 34 surface sediment samples(collected in 2015)from the Changjiang River estuary(CRE)and its adjacent areas to infer dissolved inorganic nitrogen(DIN)concentrations.Eighteen additional sets of surface sediment diatoms and corresponding upper water DIN data(collected in 2012)were used to evaluate the accuracy of the model,and the relationship between observed and diatom-inferred DIN(DI-DIN)values(R2=0.85)illustrated the strong performance of the transfer function,indicating that precise reconstructions of former DIN are possible.The diatom-DIN transfer function was applied to the diatom record from a sediment core DH8-2(1962‒2012)collected in the Fujian-Zhejiang area south of the CRE.The reconstruction based on the DI-DIN model showed a significant DIN increase from 1962-2012,reflecting the influence of human activities on the very large increase in eutrophication.Three distinct periods can be seen from the changes in DIN and diatom taxa.In the 1962-1972 period,the DIN content was relatively low,with an average of 5.94μmol/L,and more than 80%of the diatom species identified were benthic taxa.In the 1972-2004 period,as the impact of human activities intensified,large nutrient inputs caused the DIN content to increase,with an average of 8.25μmol/L.The nutrient inputs also caused a significant change in the nutrient components and a distinct increase in small planktonic taxa.In the 2004-2012 period,the DIN content continued to rise,fluctuating at approximately 10μmol/L.A continuous increase in the frequency of planktonic taxa(up to 65.48%)indicated that eutrophication was further intensified,which was confirmed by the transformation from diatom-induced red tide to dinoflagellate-induced red tide during this period.

The influence of macronitrogen (NO_3^- and NH_4^+) addition with U lva pertusa on dissolved inorganic carbon system

The influence of macronitrogen （NO3 and NH＋） addition with Ulva pertusa on dissolved inorganic carbon system in seawater was studied. The results indicate that p（C02） and HCO3 concentration decrease significantly, while pH and CO32- concentration increase significantly. When the con- centration of NO3 was less than 71 μmol/dm3 or NH4＋ was less than 49.7μmol/dm3, dissolved inorganic carbon （DIC） absorption rates by Ulva pertusa generally increased with the increasing of nitrogen concentration. The DIC decreased 151 μmol/dm3 with the addition of 71 μmol/dm3 NO3 and decreased 232 μmol/dm3 with the addition of 49.7 μmol/dm3 NH＋ after the experiment compared with DIC measured without nitrogen addition. A significant negative-correlation was found between Ac（DIC） and growth rate （#） of Ulva pertusa （r =- 0.91, P 〈0.000 1, n=11）. NH＋ had more influence on the species of inorganic carbon system than NO3.

Effects of live rock on removal of dissolved inorganic nitrogen in coral aquaria

Maintaining stable water quality is one of the key processes for recirculating coral aquaculture. Traditional aquarium systems which mainly utilized a nitrification of nitrifying bacteria attached to the surface of massive artificial filter material are difficult to maintain the oligotrophic conditions necessary for coral aquaculture. This study investigated the removal effects of dissolved inorganic nitrogen（ammonia and nitrate） by live rock（LR）, a key component in the ＂Berlin system＂ coral aquarium. The expression levels of bacterial functional genes, AOA3,amo A and nos Z, were measured on the exterior and interior of LR. The nitrifying and denitrifying bacterial abundance on LR was quantified and the nitrogen nutrient regulatory effects of LR were evaluated. The results demonstrated that LR mainly removed ammonium（NH_4~＋） from the water with a mean efficiency of 0.141 mg/（kg·h）, while the removal of nitrate（NO_3~–） was not significant. Bacterial diversity analysis showed that ammonia-oxidizing bacteria（AOB） were the most common bacteria on LR, which accounted for 0.5%–1.4% of the total bacterial population, followed by denitrifying bacteria, which accounted for 0.2% of the total population, and the ammonia-oxidizing archaea（AOA） were the least common type（〈0.01%）. The low abundance of denitrifying bacteria may be responsible for the poor nitrate（NO_3~–） removal of LR. Thus, other biological filtration methods are needed in coral aquaria to control nitrates generated from nitrification or biological metabolism.

Biogeochemical Character of Dissolved Inorganic Nitrogen and Phosphate at Plume Front in the Changjiang River

Biogeochemical character of dissolved inorganic nitrogen and phosphate at plume front is studied based on the data, which were observed in the Changjiang River Estuary in 1988. The results are as follows: The concentrations of nitrate and phosphate change abruptly -2+4at plume front and halocline. The concentrations of NO and NH are very high at 10~25 -33-4m depth. The vertical circumfluence transports NO and PO , which are released from organisms at the bottom to phytoplankton.

Distribution of dissolved inorganic nitrogen over the continental slope of the Yellow Sea and East China Sea

Based on survey data from April to May 2009, distribution and its influential factors of dissolved inorganic nitrogen (DIN) over the continental slopes of the Yellow Sea (YS) and East China Sea (ECS) are discussed. Influenced by the Changjiang (Yangtze) River water, alongshore currents, and the Kuroshio current off the coast, DIN concentrations were higher in the Changjiang River estuary, but lower (<1 μmol/L) in the northern and eastern YS and outer continental shelf area of the ECS. In the YS, the thermocline formed in spring, and a cold-water mass with higher DIN concentration (about 11 μmol/L) formed in benthonic water around 123.2°E. In Changjiang estuary (around 123°E, 32°N), DIN concentration was higher in the 10 m layer; however, the bottom DIN concentration was lower, possibly influenced by mixing of the Taiwan Warm Current and offshore currents.

秸秆还田与氮肥运筹对农田土壤可溶性氮组分的影响

为探究秸秆还田配施氮肥对农田土壤可溶性氮转化特征的影响,研发东北冷凉区土壤氮素供应能力提高的秸秆还田技术,采用田间连续定位试验,对比分析了秸秆还田方式(不还田、粉碎翻压还田、堆腐旋耕还田)与氮肥运筹(N 180、210、240 kg/hm^(2);氮肥基施、氮肥后移)作用下农田土壤无机氮(IN)、可溶性有机氮(DON)及可溶性全氮(DTN)的动态变化。结果表明,秸秆还田配施氮肥影响农田土壤可溶性氮组分含量,其作用行为受秸秆还田方式、施氮模式和生育时期的多重制约。秸秆还田配施低量氮肥(N 180 kg/hm^(2))土壤IN和DTN均低于无秸秆处理,而配施高量氮肥(N 240 kg/hm^(2))时高于无秸秆处理;秸秆还田土壤DON于生育前期(播种-拔节期)较无秸秆处理显著增加,而在生育中后期无规律性变化。随着施氮量增加,秸秆还田土壤IN和DTN显著增加,而DON仅于春玉米旺盛生长期(拔节期-灌浆期)显著增加。随着生育期推进,除秸秆堆腐旋耕还田土壤DON呈三峰曲线变化外,秸秆还田土壤IN、DON和DTN均呈双峰曲线变化,且峰值越来越低。由此可见,在东北农业产区,N 210 kg/hm^(2)用量下秸秆粉碎翻压还田配施15%氮肥的秸秆还田技术具有优化氮素管理、提高土壤肥力的潜力。

不同施肥处理添加生物炭对设施农业土壤不同形态氮的影响

生物炭在设施农业土壤中施用,对土壤氮形态具有显著影响。探明不同施肥处理添加生物炭对设施农业土壤不同形态氮的影响,可为设施农业施用生物炭减排提供科学依据。以设施菜地土壤(褐潮土)为研究对象,设置不施肥(CK)、施用有机肥(M)、化肥(F)、有机无机混施(M+F)4种处理下投入2%和4%(生物炭与土壤干质量比)生物炭处理,采用室内恒温好氧培养-气相色谱测定方法监测土壤N_(2)O释放量,测定土壤中可溶性有机氮(DON)和无机氮(N_(min))的含量,并分析DON、N_(min)含量变化及其与土壤N_(2)O释放量变化之间的关系。研究表明,生物炭的施用在不同条件下对土壤N_(2)O的释放速率和累积释放量产生不同影响。在CK和M处理下,生物炭在施用初期(第0~1.5天)显著促进了土壤中N_(2)O的释放,但随后(第2~60天),在CK处理下,生物炭的添加对N_(2)O的释放速率和累积释放量没有产生显著影响。同样地,在M处理下,生物炭的添加也未对N_(2)O的释放速率产生显著作用。然而,在培养结束时,添加4%的生物炭显著提高了土壤中N_(2)O的累积释放量。值得注意的是,在F和M+F的处理中,生物炭的加入在初期阶段(第0~2天)有效地降低了土壤N_(2)O的释放速率,这种降低效果随着生物炭施用量的增加而变得更加显著。在F和M+F处理下,添加生物炭在不同时间段内(第2~25天和第3~14天)显著增加了土壤N_(2)O释放速率,但对该速率的影响在后续阶段并不显著。培养结束后,F处理下,添加2%和4%生物炭的土壤N_(2)O累积释放量分别显著提高78%和90%;M+F处理下,添加2%和4%生物炭的土壤N_(2)O累积释放量分别显著提高80%和67%。相关性分析结果显示,在施用生物炭的土壤中,DON和N_(min)的含量与N_(2)O的排放量之间存在明显的正相关关系。表明生物炭的添加通过调整土壤中DON和N_(min)的含量,对N_(2)O的排放产生了直接影响。将生物炭投入到不同的施肥土壤中,土壤N_(2)O的释放速率和累积释放量出现不同的变化趋势,但是由于生物炭自身特性的多样性、配施化肥和有机肥种类的差异、施肥方式和时间的差异等,因此分析生物炭添加后对土壤N_(2)O累积释放量影响时,需要根据研究时的具体条件做合理分析。

Tracing the sources of nutrients through the Tsushima/Korea Strait

The nutrients from the East China Sea(ECS) through the Tsushima/Korea Strait(TS) strongly impact the eco system of the Japan Sea(JS).The complex origins of the Tsushima Warm Current and the various nutrient sources in the ECS result in complex spatial-temporal variations in nutrients in the TS.Using a physical-biological model with a tracking technique,we studied the effects of nutrient sources from the ECS on the TS.Among all the nutrient sources,the Kuroshio has the highest nutrient concentrations in the TS.Its maximum concentration occurs at the bottom,while those of rivers and atmospheric depo sition occur at the surface,and that of the Taiwan Strait occurs in the middle layer.The nutrient transport through the TS exhibits similar seasonal variations,as does the volume transport.The transport of nutrients from the Kuroshio accounts for more than 85% of the total.The transport of nutrients from the Taiwan Strait is greater during autumn and winter.The transport of dissolved inorganic nitrogen(DIN) from both rivers and atmospheric deposition through the TS peak in August.Nutrient transport cannot be equated with volume transport.The DIN in the less saline zone originates not only from rivers but also from atmospheric deposition and the Kuroshio.The transport of nutrients from the Taiwan Strait is not as significant as its volume transport in the TS.

Changes in nitrogen and phosphorus and their effects on phytoplankton in the Bohai Sea

Systematic studies of the changes in dissolved inorganic nitrogen(DIN) and dissolved inorganic phosphorus(DIP) and their effects on phytoplankton over the last 30 years in the Bohai Sea are presented.The amount of sewage disposal,use of fertilizer and the Huanghe River runoff were found to have a significant influence on the DIN or DIP concentrations in the Bohai Sea over the last 30 years.Moreover,the changes in DIN and DIP resulted in changes in the limiting nutrients of phytoplankton in the Bohai Sea from nitrogen in the early 1980s to nitrogen-phosphorus in the late 1980s,and then to phosphorus after the 1990s.In addition,changes in nitrogen and phosphorus had a significant effect on the phytoplankton community structure.The half saturation constant(Ks) was used to evaluate the effect of nutrients on the phytoplankton community structure in the Bohai Sea over the last 30 years.Cell abundance percentages of dominant phytoplankton species with high Ks values for phosphorus and low Ks values for nitrogen have decreased since the 1980s,while those of dominant phytoplankton species with low Ks values for phosphorus and high Ks values for nitrogen increased during this period.

Effects of freezing intensity on soil solution nitrogen and microbial biomass nitrogen in an alpine grassland ecosystem on the Tibetan Plateau,China

The change of freeze-thaw pattern of the Tibetan Plateau under climate warming is bound to have a profound impact on the soil process of alpine grassland ecosystem;however,the research on the impact of the freeze-thaw action on nitrogen processes of the alpine grassland ecosystem on the Tibetan Plateau has not yet attracted much attention.In this study,the impact of the freezing strength on the soil nitrogen components of alpine grassland on the Tibetan Plateau was studied through laboratory freeze-thaw simulation experiments.The 0–10 cm topsoil was collected from the alpine marsh meadow and alpine meadow in the permafrost region of Beilu River.In the experiment,the soil samples were cultivated at –10℃,–7℃,–5℃,–3℃ and –1℃,respectively for three days and then thawed at 2℃ for one day.The results showed that after the freeze-thaw process,the soil microbial biomass nitrogen significantly decreased while the dissolved organic nitrogen and inorganic nitrogen significantly increased.When the freezing temperature was below –7℃,there was no significant difference between the content of nitrogen components,which implied a change of each nitrogen component might have a response threshold toward the freezing temperature.As the freeze-thaw process can lead to the risk of nitrogen loss in the alpine grassland ecosystem,more attention should be paid to the response of the soil nitrogen cycle of alpine grasslands on the Tibetan Plateau to the freeze-thaw process.

氮沉降背景下生物炭输入对土壤可溶性有机质和无机氮的影响

利用盆栽试验探究氮沉降背景下生物炭输入对土壤可溶性有机质(DOM)和无机氮(NH_(4)^(+)-N、NO_(3)^(-)-N)含量的短期影响。氮沉降处理分别为0(对照)、40(低氮)和80 kg·N·hm^(-2)·a^(-1)(高氮),在每个氮沉降水平下生物炭施用量分别为0(对照)、12(低量)、36 t·hm^(-2)(高量),供试植物为杉木幼苗,试验进行18个月。结果表明,与对照相比,单独氮沉降处理使土壤pH下降了0.05~0.18个单位,而单独施用生物炭以及在氮沉降背景下施用生物炭处理后土壤pH则显著提高了0.26~0.91个单位(P<0.05)。单独氮沉降处理对土壤可溶性碳(DOC)含量和可溶性氮(DON)含量的影响并不明显,而单独施用生物炭以及在氮沉降背景下施用生物炭处理均显著提高了DOC(1~2倍)和DON(1~6倍)含量。同对照组比较,各处理下的土壤NH_(4)^(+)-N含量变化并不明显,高量施用生物炭处理显著提高了NO_(3)^(-)-N含量。因此,在杉木幼苗生长初期,施用适量的生物炭有利于缓解由氮沉降所引起的土壤酸化并维持DOM处于较高水平,这对亚热带人工林的可持续经营具有重要意义。

基于分源物理生态耦合模型研究东海表层溶解无机氮对叶绿素季节变化的影响

东海溶解无机氮(dissolved inorganic nitrogen,DIN)有四个主要外部来源,包括黑潮、台湾海峡、河流径流和大气沉降。为探究它们的共同作用对东海浮游植物时空变化带来的多重影响,利用添加分源模块的物理-生态耦合模型分析了东海表层不同来源DIN支持的浮游植物(以叶绿素a浓度chlorophylla,chla表征)季节变化与空间分布以及它们之间的响应关系,从而评估多源营养盐对东海陆架表层浮游植物的影响。各来源DIN支持的chl a浓度中,黑潮来源和河流径流来源先后占据主导地位,且除了河流径流来源chl a,其余三种来源chl a季节变化均呈双峰结构。不同来源chl a空间分布特征存在季节变化差异,并且各来源chl a在东海陆架不同季节存在不同的主导区域,这与不同来源DIN供给的物理过程,如环流、混合、层化以及温度变化等密切相关。研究不同来源营养盐对东海浮游植物的影响对理解多重压力下东海生态系统变化有重要意义。

单环刺螠生物扰动对沉积物-水界面氮磷扩散通量的影响

为了解单环刺螠生物扰动作用对沉积物-水界面氮磷扩散通量的影响及其持续性,于2020年11—12月,采用室内实验生态学的方法,设置低密度(LD,500尾/m^(2))、中密度(MD,2500尾/m^(2))、高密度(HD,8300尾/m^(2))处理组和1个对照组(CO,0尾/m^(2)),进行了2 d为一个实验时段,为期20 d的模拟实验。结果显示,处理组溶解无机氮(DIN)扩散通量变化范围为10.6~765.3μmol/(m^(2)·d),与对照组相比,低、中、高处理组的DIN通量分别提高了57%、76%、88%。NH_(4)^(+)是DIN的主要贡献者,对DIN的贡献在低、中、高处理组中分别占55%、65%和80%。与对照组相比,低、中、高密度组的平均NH_(4)^(+)通量分别提高了39%、111%和257%,与低、中密度处理组平均NH_(4)^(+)通量相比,高密度处理组分别提高了43.7%和23.6%。在第2~10天,NH_(4)^(+)通量处于持续增加的趋势。处理组PO_(4)^(3-)通量变化范围为-7.85~6.42μmol/(m^(2)·d),第2~6天,处理组PO_(4)^(3-)通量持续增加。研究表明,单环刺螠的生物扰动能够持续地促进DIN由沉积物向水体中扩散,且存在明显的密度效应。研究结果将为深入认识单环刺螠在水层-底栖系统耦合过程中的生态作用提供基础数据。

闽江入海断面溶解无机氮长时间序列分析及入海通量估算

为深入研究闽江口富营养化机制,于1985—2021年在闽江入海断面开展了水质监测。采用结合局部加权回归散点平滑法(LOWESS)的季节性肯达尔检验(SK检验)对断面溶解无机氮(DIN)及其各组分浓度变化趋势进行分析,同时结合水文资料对入海通量进行估算。结果表明:DIN浓度范围为0.728~3.140 mg/L,在37年间整体呈上升趋势,但不显著。各组分中NO 2-N和NH 3-N浓度分别呈显著和极显著下降趋势,而NO 3-N浓度呈极显著上升趋势。DIN组分中NO 2-N和NH 3-N比重不断减小,而NO 3-N比重不断增大,目前已成为DIN的主要组成部分。DIN入海通量范围为3.59×104~14.85×104 t,在37年间缓慢增加,其各组分入海通量长期变化趋势同浓度变化类似。从长期来看,DIN及其各组分浓度的变化趋势主要受流域环境变化及下游福州市含氮废水排放影响,而在短期则受台风、降水等一些突发环境事件的影响较大。

长河流域枯水期水体硝酸盐源解析

通过识别研究区枯水期地表水和浅层地下水中溶解态无机氮(DIN)的分布特征,结合硝酸盐稳定同位素技术与水化学方法,并利用贝叶斯稳定同位素混合模型(SIAR),定量解析长河流域水体硝酸盐污染源,为流域水生态环境的修复治理提供理论支持。结果显示,研究区枯水期水体溶解态无机氮(DIN)以NO_(3)^(-)-N为主,NO_(3)^(-)-N平均占比为91.56%;水体生物地球化学过程以硝化作用为主;硝酸盐主要来自粪便和污水;SIAR模型计算结果表明,粪便和污水、土壤氮、化肥、大气沉降对研究区地表水硝酸盐的贡献比例分别为40.80%、30.60%、25.60%和3.00%;对浅层地下水硝酸盐的贡献比例分别为39.92%、32.11%、25.87%和2.10%。研究显示,人类活动对研究区水体影响强烈,加强排污设施基础建设,改善污水排放现象,是减少区域氮污染的关键因素。

Evidence of temperature-controlled dissolved inorganic nitrogen distribution in a shallow lake

Dissolved inorganic nitrogen(DIN) plays an important role in aquatic ecosystems as an available source of nitrogen(N). Despite recent advances in our understanding of the effects of climate change on DIN in coastal waters, shallow high-latitude lakes exposed to large seasonal temperature differences have received limited research attention. Therefore,in the present study, Baiyangdian Lake(BYDL) was selected as the study area, as a typical high latitude shallow lake in North China. Based on water and sediment samples collected in spring, summer and winter seasons, DIN accumulation in sedimentary pore water and DIN diffusion fluxes at the sediment-water interface were quantified under different temperature conditions. Correlation analysis was used to establish the effects of temperature on DIN concentration and diffusion in different media. Results show that the diffusion of DIN at the lake sediment-water interface exhibited a strongly positive relationship with temperature, suggesting that high temperature conditions lead to greater DIN release from sediments. Cold temperatures cause DIN accumulation in sedimentary pore water, providing sufficient substrate for N-related bacteria in the sediment under cold temperature conditions. Temperature controls the vertical distribution of DIN by affecting its migratory diffusion and transformation at the sediment-water interface. These findings are valuable for understanding the impact of climate change on the distribution of N in inland shallow lakes,especially in high latitude shallow lakes subjected to large seasonal temperature differences throughout the year.

三亚湾海水温度季节变化及溶解无机氮的垂直分布特征

根据 2 0 0 0年 4月— 2 0 0 1年 3月在三亚湾的定点现场观测资料分析结果表明 :6— 8月份受外来冷水上升流的入侵和影响 ,使该湾水域在该季节形成明显的温跃层 ,底部和中部有明显的低温层。在上升流入侵期间 ,该湾水域平均温跃层强度为 0 .1 3 8— 0 .2 83℃·m- 1 ,最大温跃层强度为 0 .41 9— 0 .440℃·m- 1 ,底部最低水温在 2 2℃左右。 9月—翌年 3月温跃层消失 ,海水混合流动充分 ,温度垂直分布均匀。 3月份水温开始升高 ,至 5月水温总体升至最高 ,并由于高气温及强太阳的辐射作用 ,5月份形成温跃层。溶解无机氮 (DIN)的分布特征表明 ,硝酸盐、亚硝酸盐在冷水上升流入侵季节 ,其含量明显提高 ,比平时分别提高 :1 0 .2 0 %(表层 )、3 7.2 0 %(中层 )、83 .81 %(底层 )和 6 4 .0 4 %(表层 )、82 .96 %(中层 )、1 1 9.41 %(底层 )。氨态氮不直接受上升流影响 ,但季节变化特征明显。

武汉月湖水体营养物质的分布与硅藻的生态指示

通过对武汉月湖2007年1-12月水体理化指标(电导率、溶解氧、pH值、水温、透明度、无机氮、无机磷、可溶硅)、生物指标(硅藻、蓝藻、叶绿素a)的监测,结果表明:月湖水体中无机氮、无机磷含量较丰富,可溶硅含量较低;月湖水体初级生产力较高,湖泊中蓝藻密度远大于硅藻密度;月湖水体中浮游植物与生境因素有着复杂的生态网络关系。月湖水体营养盐结构不合理,在硅藻消亡后,湖泊水域中的营养组合(丰富的氮与磷,但缺乏可溶硅),这种特殊生境刺激蓝藻的生长,进一步导致硅藻的减少,使月湖浮游植物的优势种转变成蓝藻类。可溶硅在湖泊浮游植物群落由硅藻型向蓝藻演变的过程中起着重要的作用,可溶硅起始浓度水平不仅决定硅藻生产量最大值的程度,而且制约着硅藻持续时间,补偿湖泊可溶硅可能是防治湖泊富营养化的新路。

溶解无机氮在胶州湾沉积物-海水界面上的交换速率和通量研究

应用实验室培养法测定了溶解无机氮(DIN)在胶州湾16个站位沉积物-海水界面上的交换速率.结果表明,NH+4-N,NO-2-N和NO-3-N的交换速率一般分别在-0.5～1.6,0.005～0.67,-2.0～2.8 mmol/(m2@d)范围内.由于间隙水中DIN主要以NH+4-N形态存在,DIN在胶州湾沉积物-海水界面上的交换以NH+4-N的扩散为主,在大部分站位表现为由沉积物向水体的释放,NO-3-N主要来自NH+4-N的硝化反应,而NO-2-N是NH+4-N和NO-3-N之间化学转化过程的中间产物.考虑胶州湾沉积物类型,DIN在胶州湾沉积物-海水界面上的交换通量为9.68×108mmol/d,是河流输入DIN的50%左右,可提供维持胶州湾初级生产力所需DIN的52%.

霍甫水丝蚓对太湖梅梁湾沉积物影响——水界面无机氮、磷交换

根据太湖梅梁湾大型底栖动物的自然分布特征,运用沉积物——水微宇宙的实验方法评估了霍甫水丝蚓(Limnodrilus hoffmeristeri)对太湖沉积物无机氮和磷释放的影响,通过对比分析沉积物和上覆水无机氮浓度、沉积物和上覆水之间无机氮的循环规律及沉积物中无机氮的剖面特征在有/无水蚯蚓活动背景下的差异,探讨了寡毛类底栖动物霍甫水丝蚓对梅梁湾沉积物-水界面磷和无机氮交换的影响及其机制。研究表明,水蚯蚓通过生物扰动作用,促进了沉积物中的无机氮(主要是氨氮)和正磷酸盐向上覆水体中扩散,增加水蚯蚓的密度显著影响沉积物和上覆水中无机氮的浓度,而上覆水中正磷酸盐的浓度主要受生理活动-排泄的影响。