麻栎种源林叶片碳、氮、磷化学计量特征的变异

结合林木育种方法,以3个麻栎种源试验林为研究对象,测定了29个麻栎种源叶片碳、氮、磷化学计量特征.结果表明: 地点(环境)显著影响叶片碳、氮、磷、碳氮比、碳磷比、氮磷比,解释量占总变异量的13.2%～66.7%,而种源(遗传)的影响并不显著,解释量只占总变异量的2.9%～11.0%.叶片氮与碳氮比、氮与氮磷比、磷与碳磷比、磷与氮磷比均具有显著的相关性,且无论是地点间还是东西部种源间均存在共同的标准化主轴斜率.表明在单一树种(麻栎)水平上,种源间具有相似的碳、氮、磷生化过程,其叶片化学计量特征主要受环境的影响;而化学计量特征在地点间和东西部种源间稳定的相关系数反映出叶片化学计量特征的特定耦合比例不受环境和种源的影响,支持化学计量学的内稳性理论.     

中国东北样带(NECT)土壤碳、氮、磷的梯度分布及其与气候因子的关系

 以中国东北样带(NECT)为依托,基于沿样带的野外观测和土壤实测数据,分析了沿样带的土壤碳、氮、磷的空间分布格局及其与年降水、年均温之间的关系。结果表明：样带内土壤有机碳、土壤全氮、土壤有效氮、土壤全磷、土壤有效磷沿经度均呈现出东高西低的分布趋势;降水量和温度对土壤碳、氮、磷的作用强度顺序分别为土壤有效氮、土壤有机碳、土壤全氮、土壤全磷和土壤有效磷;并建立了土壤有机碳、土壤全氮、土壤有效氮、土壤全磷、土壤有效磷与年降水、年均温之间的多项式回归方程,为样带陆地碳收支评估及养分循环提供基础资料。     

辽东山区次生林林窗大小对土壤微生物量碳、氮、磷的影响

林窗干扰是次生林更新和演替过程的重要干扰类型,影响土壤的养分供应。为明确温带次生林林窗大小对土壤养分循环过程的影响,以辽东山区典型次生林内形成时间为6年的大、中、小(90~670 m~2)人工林窗为研究对象,测定了生长季不同大小林窗内0~20cm土层土壤微生物量碳、氮、磷。结果表明:与对照样地相比,大、中、小林窗0~10和10~20 cm土层土壤微生物量碳、微生物量磷、微生物量碳/全碳和微生物量磷/全磷无显著差异,且不同大小林窗间土壤微生物量碳、氮、磷以及微生物量碳/全碳、微生物量氮/全氮、微生物量磷/全磷均无显著差异。与对照样地相比,中林窗(290 m~2)10~20 cm土层土壤微生物量氮和微生物量氮/全氮显著升高,表明中林窗促进了10~20 cm土层土壤氮素的循环和有效氮素的供应。     

不同地下水位灰化薹草分解过程中木质素降解与碳、氮、磷释放的关系

为研究湿地植物分解过程中木质素分解与碳、氮、磷元素释放之间的关系及其对不同地下水位环境梯度的响应,在鄱阳湖典型碟形湖泊-白沙湖设置了200 m×300 m分解试验样地,沿地下水位梯度划分4个试验样带(从湖岸到湖心依次为GT-A, GT-B, GT-C, GT-D),采用分解袋法模拟了典型湿地植物灰化薹草在不同地下水位环境的分解过程。结果表明,分解15 d后,地下水位的升高促进了木质素的分解和碳、氮、磷元素的释放;在分解第60—90天,碳、氮、磷元素的相对归还指数随着木质素分解速率的升高而显著增大,并且相关性程度随着分解时间先增强,后减弱;分解过程中土壤pH、含水量和微生物量碳、氮对木质素的分解和碳、氮、磷元素的归还具有显著的促进作用。研究结果将有助于深化对湿地植物分解和生物地球化学循环过程的认识,为湿地自然保护区的科学有效管理提供理论依据。     

微生物抑制剂对黑藻（Hydrilla verticillata）分解过程及水体碳、氮、磷的影响研究

为了解微生物抑制剂对沉水植物衰亡分解以及水体碳、氮、磷的影响,在实验室模拟条件下研究了有无微生物抑制剂 条件沉水植物黑藻（Hydrilla verticillata）的分解过程,以及对水体与底泥碳、氮、磷的影响,并将有微生物抑制剂作为实验组,无微生物抑制剂作为对照组。结果表明：实验组沉水植物分解损失量是对照组的2.09 倍。实验组释放的碳、氮、磷量分别是对照组的2.81、1.42、1.11 倍。实验组水体碳、氮、磷含量呈现先上升后下降的变化过程,而对照组水体碳、氮、磷达到最大值后,基本保持稳定。水体碳、氮、磷的最大值,实验组条件均大于对照组,微生物抑制剂对沉水植物的分解以及在沉水植物分解过程中,对水体营养物质产生了较大的影响。因此,在进行沉水植物模拟实验时需考虑微生物对沉水植物分解的影响。     

氮、磷对小新月菱形藻无机碳利用与碳酸酐酶活性的影响

在实验室条件下研究了氮磷浓度变化对小新月菱形藻无机碳利用与碳酸酐酶活性的影响,结果显示小新月菱形藻随培养液中氮、磷浓度的升高比生长速率明显提高。低氮浓度导致胞外碳酸酐酶活性丧失,但胞内碳酸酐酶活性依然存在。高氮浓度下胞内、外碳酸酐酶活性均明显升高。胞内碳酸酐酶活性在高磷浓度下明显升高,但胞外碳酸酐酶活性并没有受到磷浓度变化的影响。高氮、磷浓度培养下的小新月菱形藻的最大光合作用速率(Vmax)、对CO2亲和力(K0.5(CO2))和光系统II最大光化学效率(Fv/Fm)均明显提高。以上结果表明小新月菱形藻可以通过改变胞内、外碳酸酐酶活性调节无机碳利用以适应不同氮磷浓度的环境。     

洞庭湖湿地土壤碳、氮、磷及其与土壤物理性状的关系

以洞庭湖3类典型湿地的8个土壤剖面为代表,研究了土壤碳、氮、磷,微生物量碳、氮、磷和土壤物理性状的分布特征.结果表明,土壤表层有机碳含量为19.63～50.20 g·kg^-1,微生物量碳为424.63～1 597.36 mg·kg^-1,微生物量碳占有机碳的比例为3.17%～4.82%;土壤表层全氮1.85～4.45 g·kg^-1,微生物量氮5.90～259.47 mg·kg^-1,微生物量氮占全氮的比例3.13%～6.42%;土壤表层微生物量磷含量顺序为:湖草洲滩地(200.99 mg·kg^-1)＞垦殖水田(163.27 mg·kg^-1)＞芦苇洲滩地(24.16 mg·kg^-1),微生物量磷占全磷的比例为1.09%～11.20%;土壤表层容重0.65～1.04 g·cm^-3;土壤表层粘粒(＜0.001mm)26.24%～39.48%.土壤表层有机碳、全氮、微生物量氮、微生物量磷的含量,湖草洲滩地＞垦殖水田＞芦苇洲滩地.土壤表层微生物量碳,垦殖水田和湖草洲滩地接近,而大于芦苇湿地;土壤表层容重,芦苇洲滩地＞垦殖水田＞湖草洲滩地;土壤表层＜0.01 mm、＜0.001 mm粘粒,湖草洲滩地、芦苇洲滩地＞垦殖水田.湿地土壤剖面中有机碳、微生物量碳、全氮、微生物量氮、微生物量磷、容重以及微生物量碳占有机碳的比例、微生物量氮占全氮的比例、微生物量磷占全磷的比例均随深度的增加而降低,至一定深度稳定,而土壤全磷在剖面上下的差异很小.湿地土壤微生物量碳、氮、磷之间呈极显著的正相关关系;土壤容重与有机碳、全氮、微生物量碳、氮、磷之间呈极显著指数负相关关系.湿地土壤＜0.001 mm粘粒与有机碳、全氮、微生物量碳、氮、磷含量呈极显著对数正相关关系.     

岷江上游高山森林溪流木质残体碳、氮和磷贮量特征

森林溪流木质残体是森林生态系统与水域之间物质循环和能量流动的主要联结之一,其碳、氮和磷贮量不仅可影响森林与溪流生态系统的结构和功能,而且与下游水体环境密切相关。因此,于2013年8月雨季以岷江上游典型高山森林为研究对象,调查了12条森林溪流木质残体的碳、氮和磷贮量分配特征,并汇算了研究区域内碳、氮和磷在溪流中单位面积的总贮量。结果表明,高山森林溪流木质残体碳、氮和磷的溪流单位面积总贮量分别为312.1 g/m2、809.5 mg/m2和110.9 mg/m2;在溪流中,木质残体碳、氮和磷贮量以径级为1—2.5 cm和2.5—5 cm的木质残体分布居多,分别共占碳、氮和磷总贮量的86.71%、87.20%和84.55%;木质残体碳、氮和磷贮量以Ⅴ腐烂级分配最多,分别共占碳、氮和磷总贮量的65.86%、67.86%和60.31%;尽管溪流各项特征与碳、氮和磷元素贮量的相关性不显著,但基本达到中度相关关系。这些结果为认识森林生态系统中以木质残体为载体的碳、氮和磷输出潜力提供了基础数据。     

洞庭湖区不同利用方式对土壤微生物生物量碳氮磷的影响

以湖南省沅江市典型湖垸为代表,通过密集取样分析,研究了洞庭湖区不同利用方式条件下农田土壤微生物生物量碳、氮、磷的变化及其和土壤碳、氮、磷的关系,发现水田土壤碳、氮和微生物生物量碳、氮明显高于旱地,水田土壤中双季稻高于一季稻;土壤磷的含量旱地稍高于水田,但土壤微生物生物量磷水田稍高于旱地.尽管在水田土壤中微生物生物量碳、氮有明显的不同,但水田土壤微生物生物量磷维持在相对稳定的水平.典型样区土壤微生物生物量碳占有机碳的比例为0.65%～7.24%,平均3.00%;土壤微生物生物量氮占全氮的比例为0.98%～7.41%,平均3.81%;土壤微生物生物量磷占全磷的比例为0.16%～7.54%,平均2.80%.土壤C/N为3.87～17.31,平均9.15;BC/BN为4.06～9.29,平均7.26.土壤微生物生物量碳、氮与土壤碳、氮之间存在极其显著的线性相关关系,但土壤微生物生物量磷占全磷之间相关关系不显著.土壤微生物生物量碳、氮、磷之间的相关关系达到了极显著水平.不同的利用方式和耕作制度导致了土壤碳、氮和微生物生物量碳、氮的差异,土壤微生物生物量碳、氮能够很好地反映洞庭湖区农田土壤碳、氮水平.     

混合生物结皮对土壤养分的影响与群落结构之关联——以黄土丘陵区的生物结皮为例

自然条件下生物结皮是藻、藓及地衣等结皮类型以不同比例组成的混合群落,显著影响土壤养分含量,目前混合生物结皮对土壤养分的影响与其群落结构的关系尚不清楚,限制了混合生物结皮土壤养分的评估。为此,研究通过测定单一组成的藻结皮、藓结皮以及80%藻+20%藓、60%藻+40%藓、40%藻+60%藓和20%藻+80%藓4个不同藻藓比例的混合生物结皮土壤有机碳、全氮、全磷、速效磷、铵态氮和硝态氮含量,研究了混合生物结皮土壤养分与其群落结构之间的关联。结果显示：(1)藓结皮层土壤有机碳、全氮、速效磷、铵态氮和硝态氮含量显著高于藻结皮,分别高出166.4%、77.2%、55.1%、56.2%和42.2%。(2)藻藓混合生物结皮土壤有机碳、全氮、速效磷和铵态氮含量与组成和盖度等结构特征有关,可以通过单一类型生物结皮土壤养分含量与盖度加权预测混合生物结皮土壤养分储量。(3)混合生物结皮土壤有机碳、全氮、速效磷和铵态氮储量实测值(x)与预测值(y)拟合的线性函数分别为y=0.97x、y=0.96x、y=1.18x和y=0.92x。(4)混合生物结皮对全磷和硝态氮含量的影响与群落结构无关。生物结皮对下层0—5 ...     

Integrated vermi-pisciculture--an alternative option for recycling of solid municipal waste in rural India

Vermicomposts as a biofertilizer can be a great option for pond manuring as they never cause any long term harm to the soil like chemical fertilizer. In this study vegetable and horticulture waste was used as an important media for vermiculture. Three separate cemented tanks (6 m(3) each) were used in the system as control tank, vermicompost fertilized tank and inorganic fertilizer manured tank. Monoculture of fish was carried out with cat fish, Clarias batrachus. The produced earthworms were used as fish feed. Regular monitoring of water parameter was conducted in three different ponds. Specifically, the algal biomass variation was quite helpful in analyzing the behavior of the ponds. NPK value of soil samples were analyzed intermittently to know the eutrophication level. Despite the hot summer temperature in northern part of India, which is not ideal for fish growth, we have recorded an encouraging growth performance in organic manured pond along with inorganic fertilizer treated and control pond. Among eutrophicated pond, the fish biomass from vermicompost fed pond showed an increasing trend compared to inorganic fertilizer treated pond. Water retention capacity of vermicompost pond soil was better in comparison to other ponds. Result shows that the low cost model by integrating two production system vermiculture and pisciculture could be a commercially and environmentally viable option.     

Intermediate Pond Sizes Contain the Highest Density,Richness, and Diversity of Pond-Breeding Amphibians

We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a significant predictor of density, species richness, and diversity of amphibians and if values peaked at intermediate pond areas. We found that in all cases a quadratic model fit our data significantly better than a linear model. Because small ponds have a high probability of pond drying and large ponds have a high probability of fish colonization and accumulation of invertebrate predators, drying and predation may be two mechanisms driving the peak of density and diversity towards intermediate values of pond size. We also found that not all intermediate sized ponds produced many larvae; in fact, some had low amphibian density, richness, and diversity. Further analyses of the subset of ponds represented in the peak of the area distribution showed that fish, hydroperiod, invertebrate density, and canopy are additional factors that drive density, richness and diversity of ponds up or down, when extremely small or large ponds are eliminated. Our results indicate that fishless ponds at intermediate sizes are more diverse, produce more larvae, and have greater potential to recruit juveniles into adult populations of most species sampled. Further, hylid and chorus frogs are found predictably more often in ephemeral ponds whereas bullfrogs, green frogs, and cricket frogs are found most often in permanent ponds with fish. Our data increase understanding of what factors structure and maintain amphibian diversity across large landscapes.     

Phosphorus retention in a constructed wetland system used to treat dairy wastewater

The aim of this study was to develop an input/output mass balance to predict phosphorus retention in a five pond constructed wetland system (CWS) at Greenmount Farm, County Antrim, Northern Ireland. The mass balance was created using 14-months of flow data collected at inflow and outflow points on a weekly basis. Balance outputs were correlated with meteorological parameters, such as daily air temperature and hydrological flow, recorded daily onsite. The mass balance showed that phosphorus retention within the system exceeded phosphorus release, illustrating the success of this CWS to remove nutrients from agricultural effluent from a dairy farm. The last pond, pond 5, showed the greatest relative retention of 86%. Comparison of retention and mean air temperature highlighted a striking difference in trends between up-gradient and down-gradient ponds, with up-gradient ponds 1 and 2 displaying a positive quadratic relationship and down-gradient ponds 3 through 5 displaying a negative quadratic relationship.     

Effects of aquatic insect predators on zooplankton in fishless ponds

We removed the surface-orienting aquatic insects from a fishless pond to determine their predation effects on zooplankton behavior and size structure. A second fishless pond served as the unmanipulated reference system in this two year study. In the reference pond and the treatment pond prior to manipulation, daphnids exhibited pronounced diel vertical migrations. Following the removal of surface-orienting aquatic insects from the treatment pond, daphnid migration changed to a reverse migration strategy that was significantly different from that observed in the reference system. Average daphnid body size increased significantly following predator removal in the treatment system. Our data indicate that predation by aquatic insect predators, such as notonectids and dytiscids, may affect daphnid migration behavior in fishless systems. Vertical migration by daphnids may allow coexistence with surface-orienting insects in ponds that are deep enough to provide a spatial refuge from these predators.     

Once a pond in time: employing palaeoecology to inform farmland pond restoration

The restoration of highly terrestrialized farmland ponds that combines the removal of woody vegetation and pond sediment greatly enhances aquatic biodiversity. Nonetheless, questions remain regarding the historical precedent of pond restoration, and particularly if post‐restoration aquatic macrophyte communities resemble pre‐terrestrialization assemblages. We used a paleoecological approach to address these questions for a typical, recently restored farmland pond in Norfolk, eastern England. Plant and animal remains in pond sediment cores were used to infer decadal‐centennial scale changes to pond communities and to identify past pond management events. We then evaluated the resemblance of restored and historical assemblages by comparisons with contemporary post‐restoration vegetation data. Based on changes in the abundance of terrestrial leaf remains and other indicators (increases followed by declines of aquatic organisms), the study pond appears to have a long history (going back to the early‐1800s) of canopy management (at least three inferred management events), but after the mid‐1970s, steady and substantial increases in terrestrial indicators suggest cessation of management resulting in uninterrupted terrestrialization. Aquatic macrophyte communities arising after restoration showed some similarities with historical assemblages, but also contained apparently new species. This study demonstrates how paleolimnological methods can improve understanding of pond ecological histories to better inform restoration targets and practices.     

An ensemble data assimilation modeling system for operational outdoor microalgae growth forecasting

Microalgae have received increasing attention as a potential feedstock for biofuel or biobased products. Forecasting the microalgae growth is beneficial for managers in planning pond operations and harvesting decisions. This study proposed a biomass forecasting system comprised of the Huesemann Algae Biomass Growth Model (BGM), the Modular Aquatic Simulation System in Two Dimensions (MASS2), ensemble data assimilation (DA), and numerical weather prediction Global Ensemble Forecast System (GEFS) ensemble meteorological forecasts. The novelty of this study is to seek the use of ensemble DA to improve both BGM and MASS2 model initial conditions with the assimilation of biomass and water temperature measurements and consequently improve short-term biomass forecasting skills. This study introduces the theory behind the proposed integrated biomass forecasting system, with an application undertaken in pseudo-real-time in three outdoor ponds cultured with Chlorella sorokiniana in Delhi, California, United States. Results from all three case studies demonstrate that the biomass forecasting system improved the short-term (i.e., 7-day) biomass forecasting skills by about 60% on average, comparing to forecasts without using the ensemble DA method. Given the satisfactory performances achieved in this study, it is probable that the integrated BGM-MASS2-DA forecasting system can be used operationally to inform managers in making pond operation and harvesting planning decisions.     

Whole-body enantiomorphy and maternal inheritance of chiral reversal in the pond snail Lymnaea stagnalis

Sinistral and dextral snails have repeatedly evolved by left-right reversal of bilateral asymmetry as well as coiling direction. However, in most snail species, populations are fixed for either enantiomorph and laboratory breeding is difficult even if chiral variants are found. Thus, only few experimental models of chiral variation within species have been available to study the evolution of the primary asymmetry. We have established laboratory lines of enantiomorphs of the pond snail Lymnaea stagnalis starting from a wild population. Crossing experiments demonstrated that the primary asymmetry of L. stagnalis is determined by the maternal genotype at a single nuclear locus where the dextral allele is dominant to the sinistral allele. Field surveys revealed that the sinistral allele has persisted for at least 10 years, that is, about 10 generations. The frequency of the sinistral allele showed large fluctuations, reaching as frequent as 0.156 in estimate under the assumption of Hardy-Weinberg equilibrium. The frequency shifts suggest that selection against chiral reversal was not strong enough to counterbalance genetic drift in an ephemeral small pond. Because of the advantages as a model animal, enantiomorphs of L. stagnalis can be a unique system to study aspects of chirality in diverse biological disciplines.     

滩涂海水种植-养殖系统细菌生态学研究

滩涂海水种植-养殖系统是一种新型的生态养殖模式．对种植红树林的滩涂种植-养殖系统中细菌的生物量分布和水质的分析结果表明,由于红树林的净化作用,该系统内的水质达到Ⅱ～Ⅲ类海水水质标准,而对照塘的处于Ⅳ、Ⅴ类水质标准．系统中处理塘的异养菌、弧菌、磷细菌和产酶类细菌的数量比未种红树林的对照塘低1～2个数量级．用CORREL软件分析了细菌与水质的相关关系,异养菌、弧菌、磷细菌和产酶类细菌的数量与水体中的氮磷含量呈正相关．其中异养菌与弧菌的相关系数为0．9205,与氮磷的相关系数为0．6535(N)、0．8342(P),表明异养菌和弧菌可作为滩涂海水养殖系统水质的生物监测指标．     

Hydrodynamic performance of pilot-scale duckweed,algal-based,rock filter and attached-growth media reactors used for waste stabilisation pond research

The specific nature of fluid dynamics within waste stabilisation ponds can have a determining influence on their functional treatment performance. This paper presents the results of hydraulic tracer experiments undertaken to characterise the hydrodynamic behaviour of several pilot-scale advanced pond treatment systems (a duckweed-based pond, a conventional algal-based ‘open’ pond, a rock filter and a novel horizontal-flow attached-growth media reactor) investigated for their effectiveness at polishing a full-scale tertiary pond effluent. Duplicate tracer studies were undertaken for each of the four experimental reactors with the aid of the fluorescent dye rhodamine WT. Results from tracer studies showed flow distribution in all reactors to be highly dispersed with varying degrees of dead space volume and short-circuiting in all pilot reactors, indicating that a percentage of the total reactor volume across all treatment systems was inactive. Results from a number of calculated parameters of hydraulic performance showed that hydrodynamic efficiency was greatest in the novel horizontal-flow attached-growth media system, where a possible baffling of inflowing wastewater was thought to have promoted improved hydraulic operation. Outcomes from this research in general highlight the importance of undertaking detailed characterisations of the hydrodynamic operation of experimental pond systems and also emphasise the value of pre-validating the hydraulic design of experimental reactors used for stabilisation pond research.     

池塘循环水养殖对混养草鱼食用品质的影响

为探究养殖模式对草鱼(Ctenopharyngodon idellus)鱼肉品质的影响,实验对两种养殖模式下(传统池塘养殖和池塘循环水养殖)草鱼的食用品质进行了差异比较。结果表明,循环水养殖草鱼肌肉白度和弹性高于传统池塘养殖的草鱼,且其不饱和脂肪酸和必需氨基酸含量均显著高于传统池塘养殖;其中, n-3和n-6系列不饱和脂肪酸含量显著高于传统池塘养殖草鱼,是其1.2倍,使得草鱼的肌肉品质和营养品质更佳。此外,循环水养殖可降低草鱼中带有土腥味和青草味的己醛、庚醛和1-辛烯-3-醇等物质的含量,且鲜味核苷酸(IMP)含量高于传统池塘养殖草鱼,使得草鱼的风味更鲜美、浓厚。研究表明,循环水养殖草鱼的肌肉品质和营养特性均优于传统池塘养殖。