氮磷营养限制影响三角褐指藻光合无机碳利用和碳酸酐酶活性

以海洋硅藻三角褐指藻为实验材料, 研究了不同氮磷比培养对其光合无机碳利用和碳酸酐酶活性的影响, 结果显示三角褐指藻生长速率在N:P=16:1时最大, 高于或低于16:1时明显下降, 表明其最适生长受到氮磷的限制。氮限制(N:P=4:1或1:1)导致叶绿素a含量分别下降30.1% 和47.6%, 磷限制(N:P=64:1或256:1)下降39.1%和52.4%, 但氮或磷限制对叶绿素c含量并没有明显影响。不同营养水平培养对光饱和光合速率具有明显的影响, 与营养充足培养相比, 在严重氮磷限制(N:P=1:1或256:1)培养下光饱和光合速率分别下降39.7%和48.0%, 光合效率与暗呼吸速率也明显下降。在氮磷限制培养下藻细胞pH补偿点明显下降; K0.5CO2值在磷限制下降低30%, 表明磷限制有助于提高细胞对CO2的亲和力, 但氮限制并没有明显影响。在氮磷限制培养的细胞反应液中Fe (CN)63-浓度下降速率较慢, 表明在氮磷限制环境中生长的细胞质膜氧化还原能力明显低于营养充足条件下生长的细胞。氮磷限制也导致胞内、外碳酸酐酶活性明显下降, 其中在氮限制下胞外碳酸酐酶活性分别下降50%和37.5%, 在磷限制下下降22.3%和42.1%。严重的氮(N:P=1:1)或磷(N:P=256:1)限制导致胞内碳酸酐酶活性下降36.5%和42.9%。研究结果表明, 三角褐指藻细胞在氮磷营养限制的环境中, 可以通过调节叶绿素含量、无机碳的利用方式和碳酸酐酶的活性以维持适度的生长。       

丝藻光合作用无机碳利用研究

丝藻pH补偿点为9．2,表明其具有较低的CO2补偿点,不同pH值下丝藻光合作用放氧速率明显大于理论上从HCO3－脱水来的CO2供应速率,表明其具有利用HCO3－的能力,未检测到丝藻有胞外碳酸酐酶活性,胞内碳酸酐酶的活性随培养液中CO2浓度的升高而降低。     

不同理化因子对雨生红球藻CG-11碳酸酐酶活性的影响

以雨生红球藻CG-11为实验藻株,探讨在不同CO2、HCO3-、Zn2＋浓度以及pH和氮磷比例条件下,藻细胞的碳酸酐酶活性对这些理化因子的响应。结果表明,通入空气实验组的碳酸酐酶活性最高,为（75.20±1.53）U·mg-1（Chla）,通入5%CO2条件下的碳酸酐酶活性为（9.96±1.43）U·mg-1（Chla）;高浓度HCO3-对碳酸酐酶活性亦具有明显抑制作用,培养液中可溶性无机碳的浓度与碳酸酐酶活性呈负相关;在实验设置的pH范围内,pH9.0时碳酸酐酶活性最高,为（62.32±3.25）U·mg-1（Chla）;适当的氮磷比与Zn2＋浓度显著提高了雨生红球藻CG-11的生长速率,碳酸酐酶的活性亦有明显提高。     

碳酸酐酶在中肋骨条藻光合作用中的作用

探讨了在正常空气条件下生长的中肋骨条藻(Skeletonema costatum)的碳酸酐酶(CA)在其光合固碳中的作用.在中肋骨条藻的胞内和胞外均有CA活性,但胞外CA活性很低.CA抑制剂AZ(乙酰唑磺胺)对中肋骨条藻的光合放氧速率没有明显影响,而CA抑制剂EZ(乙氧苯唑胺)对其光合放氧速率有强烈的抑制作用.EZ的抑制作用使细胞最大光合速率、饱和光强和无机碳亲和力下降,无机碳的补偿点和光呼吸提高,使强光下光抑制作用增强.这些结果表明:中肋骨条藻的胞外CA在其光合作用中所起的作用较小,而其胞内CA通过催化胞内碳库中的HCO-3快速转化成CO2,提高胞内CO2的有效供给,从而提高细胞光合固碳能力和对逆境(高O2、强光和低CO2)的适应能力.     

不同氮磷浓度对莱布新月藻生长与脂溶性物质含量的影响

以莱布新月藻Closterium leibleinii为试材,利用单因子分析研究不同氮、磷浓度培养的莱布新月藻生长及脂溶性物质含量变化,为其作为生物柴油开发提供基础资料。结果表明,莱布新月藻生长的最适氮浓度为5.30 mg·L^–1,其最大生长速率为3.675×10⁶个·L^–1·d^–1;最适磷浓度为0.02 mg·L^–1,最大生长速率为4.05×10⁵个·L^–1·d^–1。在最适氮磷浓度BG11培养下粗脂约占藻体干重的88.04%。莱布新月藻在适宜的氮磷浓度培养基中生长速率较快,脂溶性物质含量高,可作为一种较有潜力的植物开发生物柴油。     

CO2浓度变化对拟柱胞藻生长与光合作用的影响

为了探讨大气CO₂浓度升高对水华藻类的影响,利用水华蓝藻-拟柱胞藻作为实验材料,研究了CO₂浓度升高对其生长生理和光合作用的影响,结果表明CO₂浓度升高,导致拟柱胞藻的生物量、最大光合放氧速率、光合效率显著增加。当CO₂浓度为700 mg/L以下,暗呼吸速率和光饱和点无明显影响,而CO₂浓度为1000 mg/L时,暗呼吸速率和光饱和点显著提高。随着CO₂浓度增加,藻细胞光合作用对无机碳的亲和力降低,同时胞外碳酸酐酶活性显著下降。这表明大气CO₂浓度的增加,有利于拟柱胞藻的生长和光合,进而增加了水华发生的风险。     

华北平原冬小麦田土壤胞外/内酶活性对长期CO2浓度升高的响应

针对农田胞外和胞内酶活性响应CO₂浓度升高认识不足的现状,依托华北平原冬小麦种植区北京昌平试验站长期开放式CO₂富集平台,设置常规和升高两组CO₂浓度处理,研究冬小麦田土壤胞外和胞内酶活性的变化及影响因素。结果表明:CO₂浓度升高促进胞外碳获取酶活性,不影响胞外氮获取酶活性以及全部胞内酶活性。通过量化碳、氮获取酶的胞外胞内比发现,CO₂浓度升高在冬小麦成熟期增强了碳获取酶胞外胞内比,但降低了氮获取酶胞外胞内比。胞外碳、氮获取酶活性都与土壤pH值呈负相关;而胞内碳获取酶活性与土壤含水量正相关,胞内氮获取酶活性与微生物生物量负相关。CO₂浓度升高导致上述大部分酶活性变化驱动因素的作用消失,仅存在土壤全氮与胞内碳获取酶活性负相关。研究结果强调了对胞内酶开展研究的重要性,为理解土壤过程对全球变化因素的响应提供了新见解。     

氮磷比率对3种典型赤潮藻生长的影响

采用实验室内一次性培养的方法,在贫磷和富磷条件下分别测定了不同氮磷比率对3种典型赤潮藻东海原甲藻、球形棕囊藻和尖刺拟菱形藻生长的影响。结果表明,这3种藻的最适氮磷比率分别为30：1、30：1和10：1。当N：P比率介于0—100：1之间时,3种赤潮藻的生长速率与营养盐浓度的关联度大于氮磷比率。东海原甲藻和球形棕囊藻对营养盐的需求量相对较高,在贫磷条件下的生长速率显著低于富磷条件;尖刺拟菱形藻对营养盐的需求量明显较低,在贫磷条件下可保持较高的生长速率。     

蛋白核小球藻生长和无机碳利用对不同光照强度和CO_2浓度的响应

为了探讨光照强度和CO_2浓度对蛋白核小球藻(Chlorella pyrenoidosa)生长、无机碳利用的复合效应,丰富绿藻中无机碳浓缩机制的资料,该文设置两种光照强度(40和120μmol photons×m–2×s–1)和两种CO_2浓度(0.04%和0.16%)组合成4种条件,比较了蛋白核小球藻生长、无机碳浓度、pH补偿点、光合放氧速率、碳酸酐酶(CA)活性和α-CA基因转录表达对这4种培养条件的响应。结果发现:蛋白核小球藻在高光强高CO_2浓度组生长最快;低光强高CO_2浓度组培养体系中总无机碳浓度为1 163.3μmol×L–1,显著高于其他3组;高光强低CO_2浓度组藻的p H补偿点最高(9.8),而低光强高CO_2浓度组藻的p H补偿点最低(8.6);低光强高CO_2浓度组藻的最大光合速率(Vmax)和最大光合速率一半时的无机碳浓度(K0.5)最高,分别是其他3组的1.28-1.91倍和1.61-2.00倍;高光强低CO_2浓度组藻的胞外CA活性最高;而低光强低CO_2浓度组藻的胞外α-CA基因表达量显著高于其他3组。以上结果表明低CO_2浓度可促进蛋白核小球藻的pH补偿点和无机碳亲和力的提高,诱导胞外CA活性及α-CA基因的表达;该藻主要以HCO_3~–为无机碳源,其对无机碳的利用受光照的调节。     

赤潮藻中肋骨条藻的光合作用对海水pH和N变化的响应

为探讨赤潮发生时中肋骨条藻 (Skeletonemacoatatum)的光合作用生理变化 ,研究了不同无机氮 (N)水平上 ,海水pH值升高对其胞外碳酸酐酶 (CA)和光合生理特性的影响。海水pH从 8.2升至 8.7时 ,中肋骨条藻胞外CA被诱导 ,细胞对无机碳的亲和力 (1/Km)提高 ;在pH8 7时 ,高N条件下的胞外CA活性是低N条件下的 3倍 ,1/Km 值也提高了 80 %。单位叶绿素a的最大净光合能力 (Pam)在不同pH和N水平上没有显著差异 ;但单位细胞的最大净光合能力 (Pcm)提高了 10 0 %。这些结果表明 ,赤潮发生时 ,中肋骨条藻通过启动无机碳浓缩机制 (CCM) ,提高细胞对无机碳利用效率 ,使其在低CO2 (高pH)环境下维持光合机构正常运行 ;充足的N源有利于提高CCM的效率 ,从而提高CO2 环境下的光合固碳能力。     

黄渤海海水养殖自身污染的评估

探讨了投饵和非投饵两种养殖方式自身污染对海洋环境的影响.结果表明,海水养殖产量与营养盐类、COD和赤潮发生次数均呈正相关关系,其中无机氮含量和赤潮发生次数与虾养殖产量有显著正相关关系,说明海水养殖自身污染对邻近海域富营养化及赤潮发生有一定影响.通过黄渤海海水养殖向海洋排泄氮、磷、COD等污染物估算,分别占相应陆源污染物排海量的2.8%、5.3%、1.8%.虽然与人类其他活动向海洋排污量相比,水产养殖的排污量所占比重还不算大,对于某些局部水域,特别是海水养殖密集区,将对海洋环境的影响产生叠加作用,很可能成为刺激近海富营养化和赤潮发生的一个重要因素,应引起足够的重视.     

Is inorganic nutrient enrichment a driving force for the formation of red tides?: A case study of the dinoflagellate Scrippsiella trochoidea in an embayment

Red tides (high biomass phytoplankton blooms) have frequently occurred in Hong Kong waters, but most red tides occurred in waters which are not very eutrophic. For example, Port Shelter, a semi-enclosed bay in the northeast of Hong Kong, is one of hot spots for red tides. Concentrations of ambient inorganic nutrients (e.g. N, P), are not high enough to form the high biomass of chlorophyll a (chl a) in a red tide when chl a is converted to its particulate organic nutrient (N) (which should equal the inorganic nutrient, N). When a red tide of the dinoflagellate Scrippsiella trochoidea occurred in the bay, we found that the red tide patch along the shore had a high cell density of 15,000 cells ml⁻¹, and high chl a (56 μg l⁻¹), and pH reached 8.6 at the surface (8.2 at the bottom), indicating active photosynthesis in situ. Ambient inorganic nutrients (NO₃, PO₄, SiO₄, and NH₄) were all low in the waters and deep waters surrounding the red tide patch, suggesting that the nutrients were not high enough to support the high chl a >50 μg l⁻¹ in the red tide. Nutrient addition experiments showed that the addition of all of the inorganic nutrients to a non-red-tide water sample containing low concentrations of Scrippsiella trochoidea did not produce cell density of Scrippsiella trochoidea as high as in the red tide patch, suggesting that nutrients were not an initializing factor for this red tide. During the incubation of the red tide water sample without any nutrient addition, the phytoplankton biomass decreased gradually over 9 days. However, with a N addition, the phytoplankton biomass increased steadily until day 7, which suggested that nitrogen addition was able to sustain the high biomass of the red tide for a week with and without nutrients. In contrast, the red tide in the bay disappeared on the sampling day when the wind direction changed. These results indicated that initiation, maintenance and disappearance of the dinoflagellate Scrippsiella trochoidea red tide in the bay were not directly driven by changes in nutrients. Therefore, how nutrients are linked to the formation of red tides in coastal waters need to be further examined, particularly in relation to dissolved organic nutrients.     

不同林窗马尾松凋落叶与土壤养分变化研究

以现有42年生的马尾松（Pinus massoniana）人工纯林,经过采伐形成4种不同大小有效面积的林窗（100、400、900和1 600 m²）为研究对象,以未经采伐的42年生马尾松人工纯林为对照样地,采用凋落叶分解袋法,研究不同大小有效面积林窗对马尾松凋落叶、土壤C、N、P及化学计量比和养分损失率的影响。研究结果表明：（1）不同大小有效面积林窗下的马尾松凋落叶、土壤C、N、P含量及养分损失率除土壤P含量和马尾松凋落叶P养分损失率外,均存在显著差异。随着林窗有效面积G1~G4的增大,马尾松凋落叶C、N、P含量均呈降低趋势,三者均在G3林窗体现出较小值。马尾松凋落叶C、N、P养分损失率、土壤C、N、P养分含量多呈抛物线趋势,且均在G2或G3林窗体现出最大值。（2）不同大小有效面积林窗下的马尾松凋落叶、土壤C/N/P均存在显著差异。随着林窗有效面积G1~G4的增大,马尾松人工林土壤C/N/P基本呈抛物线变化趋势,土壤C/N在G3林窗出现最大值,土壤C/P、N/P均在G2林窗体现出最大值;土壤C/N、C/P、N/P变异系数分别为13.31%、16.51%、17.21%。马尾松凋落叶C/N、C/P均在G3体现出最小值。（3）马尾松凋落叶C、N含量与土壤C、C/N/P及环境因子的相关性较强,P含量与它们的相关性较弱;C/N与土壤P、C/N/P及环境因子的相关性较强,C/P、N/P与土壤C/P及环境因子的相关性较强;C、N养分损失率与土壤C、C/N、C/P及环境因子的相关性较强,P养分损失率与土壤C、N、P含量及其化学计量比和环境因子的相关性较弱。土壤C、N、P含量及其化学计量比与环境因子的相关性较强。     

初析赤潮成因研究的围隔实验结果Ⅱ.浮游植物群落演替与甲藻赤潮

探讨了甲藻赤潮与浮游植物演替的关系．多次国隔生态系实验结果表明,在水体相对稳定的生态系中,富营养后总是先发生硅藻的水华或赤潮．随后浮游植物会演替成占优势的甲藻,甚至形成甲藻赤潮．维生素Ｂ（１２）的异常增多可能加速这种演替的进程．但这种稳定水体若受到扰动,将干扰演替,使硅藻水华持续不断地发展,阻碍甲藻形成优势．这可以防止甲藻赤潮的生成．     

Effects of nitrogen,phosphorus, iron and silicon on growth of five species of marine benthic diatoms

The effects of nitrogen, phosphorus, iron and silicon on growth of five species of marine benthic diatoms, namely Navicula patrickae, Nitzschia panduriformis, Navicula thienemannii, Nitzschia longissima and Navicula atomus were studied by single factor experiments and the optimal concentration ratios of the four nutrient elements beneficial for diatoms growth were screened out separately using the L₉ (3⁴) orthogonal design. The results highlighted that nitrogen, phosphorus, iron and silicon all had highly significant effects on growth of five diatoms while the diatoms growth rates reached the highest averagely in the 2nd to the 6th culture day. In addition, the optimal concentrations (mg/L) of four nutrients suitable for diatoms growth were found higher than that in f/2 medium except that Nitzschia longissima had the same concentration of nitrogen as that in f/2 medium which is optimal for growth. Moreover, the optimal growth concentrations of four elements for five diatoms varied in the range of 12.36–74.16 mg/L for nitrogen, 1.70–3.98 mg/L for phosphorus, 2.00–4.00 mg/L for iron, 23.01–69.03 mg/L for silicon, respectively. By means of the orthogonal test of four nutrients for five benthic diatoms, the optimal concentration ratios N:P:Fe:Si (mg/L) were obtained as follows: 74.16:2.27:3.33:23.01 for N. patrickae; 37.08:3.98:4.00:11.50 for N. panduriformis; 49.44:3.98:3.33:34.51 for N. thienemannii; 12.36:1.70:4.00:11.50 for N. longissima; 74.16:2.27:4.00:69.03 for N. atomus.     

黄河三角洲贝壳堤土壤微生物生物量对不同生境因子的响应

从土壤微生物生物量角度分析黄河三角洲贝壳堤不同生境的土壤肥力状况,基于黄河三角洲贝壳堤植被类型,以4种不同生境的土壤为研究对象,测定了微生物生物量碳、氮、磷和相关的土壤理化性质。结果表明,不同生境中土壤微生物生物量碳(MBC)、土壤微生物生物量(MBN)、土壤微生物生物量(MBP)均值均为滩脊背海侧高潮线向海侧,且表现出明显的垂直分布特征:0—5 cm5—10 cm10—20 cm20—40 cm40—60 cm。土壤MBC、MBN、MBP占土壤有机碳(SOC)、全氮(TN)、全磷(TP)百分比变化范围分别为1.09%—3.48%、2.62%—7.27%、0.78%—2.86%,滩脊、背海侧和高潮线处MBC/SOC无显著差异(P0.05),但显著高于向海侧MBC/SOC(P0.05)。土壤MBN/TN、MBP/TP的变化趋势为滩脊和背海侧向海侧和高潮线。滩脊和背海侧土壤微生物碳、氮、磷的非生物限制性因子为土壤含水量、p H值、含盐量;向海侧和高潮线区域土壤微生物碳、氮、磷的非生物限制性因子为含水量和pH值。滩脊、背海侧和高潮线土壤微生物生物量碳、氮、磷及土壤养分间的相关关系显著或极显著,且协同性和稳定性高,表明土壤微生物生物量碳、氮、磷可以作为判断黄河三角洲贝壳堤土壤肥力状况的生物学指标,这为黄河三角洲贝壳堤的土壤肥力管理和植被恢复提供一定的理论依据。     

Marine‐derived Nutrients from Green Turtle Nests Subsidize Terrestrial Beach Ecosystems

Spatially separated ecosystems are often linked by nutrient fluxes. Nutrient inputs may be transferred by physical vectors (i.e., wind and water) or by biotic vectors. In this study, we examine the role of green turtles (Chelonia mydas) as biotic transporters of nutrients from marine to terrestrial ecosystems, where they deposit eggs. We compare low and high nest density sites at Tortuguero, Costa Rica, the largest green turtle rookery in the western hemisphere. Four plant species (Costus woodsonii, Hibiscus pernanbucensis, Hymenocallis littoralis, Ipomoea pes‐caprae) were analyzed at both nest density sites for ¹⁵N, total carbon, nitrogen, and phosphorus, and vegetation cover. Sand was analyzed for ¹⁵N and total nitrogen. Vegetation at high nest density sites had higher total nitrogen, which was correlated with higher δ¹⁵N values, suggesting nutrient input from a marine source. The dominant plant species changed between low and high nest density sites, indicating that turtle‐derived nutrients may alter the plant community composition. The trend in δ¹⁵N values of sand was similar, although less pronounced than that of the vegetation. Sand may be a poor integrator of nutrient input due to low nutrient adsorption and high rate of leaching. Sea turtles have previously been shown to deposit considerable amounts of nutrients and energy on nesting beaches. In this study, we estimate annual nitrogen and phosphorus contributions at Tortuguero are 507 and 45 kg/km, respectively, and we demonstrate that beach vegetation likely assimilates a portion of these marine‐derived nutrients.     

虾池常见微藻种群温度、盐度和氮、磷含量生态位

就温度、盐度、氮磷含量设计试验,对4种虾池常见微藻种群新月菱形藻、啮蚀隐藻、微绿球藻、蛋白核小球藻的生态位进行研究.结果显示：啮蚀隐藻在温度和盐度资源上的生态位宽度值最大,分别达0.980和0.988,新月菱形藻在氮、磷含量资源上的生态位宽度值最大,达0.990,蛋白核小球藻在各资源的生态位宽度值均最小,平均只有0.926;啮蚀隐藻与蛋白核小球藻在温度和盐度资源上的生态位重叠值最小,分别为0.809和0.702,啮蚀隐藻与新月菱形藻在氮、磷含量资源上的生态位重叠值最小,只有0.829,蛋白核小球藻与微绿球藻在温度、盐度和氮、磷含量资源上的生态位重叠值均最大,分别为0.986、0.974和0.989.表明在养殖水环境调控过程中,啮蚀隐藻适宜与新月菱形藻、微绿球藻或蛋白核小球藻共同培育,而蛋白核小球藻和微绿球藻对资源的竞争性明显,不适合同时引入同一池塘进行培育.     

秦皇岛海域褐潮生消过程中营养盐特征

2009—2015年在秦皇岛海域发生的褐潮给当地海水养殖业和滨海旅游业造成巨大损失,也对海洋生态系统造成破坏性影响。营养盐是藻类生长的重要生源要素,研究其在褐潮生消过程中的变化特征,对于揭示褐潮发生的营养学机制具有重要意义。基于2014年4—6月在秦皇岛褐潮多发海域30个站位的调查数据,对褐潮发生前后营养盐特征及其与抑食金球藻的关系进行了研究。结果表明: 4、5、6月溶解态氮(DN)浓度分别为265.65、355.36和323.71 μg·L^-1,其中,溶解态有机氮(DON)浓度分别为196.98、242.88和177.69 μg·L^-1,在DN中的占比分别为74.2%、68.3%和54.9%;4、5、6月溶解态磷(DP)浓度分别为15.95、11.39和11.14 μg·L^-1,4、5月PO₄^3--P在DP中占比较大,分别为74.8%和80.9%,6月溶解态有机磷(DOP)占比升至66.2%,PO₄^3--P占比降至33.8%;4、5、6月SiO₃^2--Si浓度分别为70.95、181.13和120.68 μg·L^-1。除DON和5月无机氮(DIN)外,其他营养盐浓度的平面分布均整体呈近岸高、离岸低的趋势,高值区多出现在河口。通过R型-因子分析和营养盐结构分析发现,4月,褐潮处于发展阶段,DOP可能是抑食金球藻生长的主要控制因子;5月,褐潮处于维持阶段,水温成为主要控制因子,水温大于12 ℃即可发生褐潮;6月,褐潮开始消亡,PO₄^3--P对浮游植物群落结构具有更大的影响力。DON为诱发褐潮爆发的关键水质因子,其阈值浓度为 150 μg·L^-1,且DON/DIN值应大于1。     

Deep degassing as a reason for abnormally high bioproductivity of paleobasins and mass destruction of hydrobionts

An abnormally high bioproductivity of modern water basins arises as two factors are combined, i.e., cold surface waters rich in oxygen and moderate gas flows ascending from the fault zones at the sea bottom. Gas bubbles bring nutrients of endogenous nature to the surface; these are nitrogen, phosphorus, and microelements, which provide rapid development of phytoplankton, the basis of food chains. Quasiperiodic intensification of deep degassing results in reducing gases blowing through the surface water layer and rapid mass destruction of the aerobic biota and intense development of anaerobic organisms (red tide). This scenario also occurred in the past geologic epochs.