相关分析在探讨洪泽湖富营养化主要控制因子分析中的应用

采用相关分析方法探讨了洪泽湖叶绿素a与湖水理化因子之间的相互关系及各种环境因子对洪泽湖富营养化的影响,根据分析结果确定主要控制因子,为洪泽湖综合整治提供科学依据。

大连市洗衣粉无磷化推广、生产、使用的调查与分析

通过系统的社会调查 ,污染源统计分析 ,提出大连市含磷洗衣粉对近岸海域富营养化的贡献率。对洗衣粉的无磷化推广、生产及使用提出科学的论证 。

Preliminary Discussion on the Sea Water Quality Status in the 2008 Olympics Boat-sailing Field and Adjacent Area

A cruise of survey in the 2008 Olympics boat-sailing field and adjacent area was carried out on August 28^th, 2003. Preliminarily analysis on the eutrophication status was made on the basis of the content of dissolved inorganic nitrogen （DIN）, dissolved inorganic phosphate （PO4-P）, dissolved oxygen（DO） and chemical oxygen demand （COD） as well. The results indicated that in most of the survey area, water quality was in accordance with the 1^st class National Seawater Standard except the average concentration of petroleum hydrocarbon which was beyond the 2^nd class National Seawater Standard. The concentrations of PO4-P as well as DIN were mainly influenced by the runoff or drainage from lands, with a comparatively higher concentration in the coastal areas from the Fushan Bay to the Shilaoren bathing beach. The distribution of eutrophication index （El） showed that part of the survey area was in a state of slight eutrophication The eutrophication was mostly influenced by the land runoff or drainage and related factors. The sea water quality of the Olympic boat-sailing field was fine and just slightly polluted on the whole.

CHANGES OF ENDOGENOUS HORMONE CONTENTS DURING FLORAL BUD AND VEGETATIVE BUD DIF FERENTIATION IN THIN CELL LAYER CULTURE OF CICHORIUM INTYBUS L. EXPLANT

The sectioned thin cell layers (TCL) of flower stalk of Cichorium intybus L. were cultured in MS medium supplemented with NAA and BA or IAA and BA where floral and vegetative buds were developed from the explant. Endogenous IAA, DHZ+DHZR, iPA increased significantly during the floral bud formation, while Z+ZR remained changed. The levels of cytokinins, DHZ+DHZR, iPA, and Z+ZR all increased significantly during the vegetative bud formation, however IAA level was reduced during the first 7 days of culture and increased to two thirds of initial values on the day when the bud primordia were formed. The results suggested that the initiation of floral buds was associated with a high IAA/CTK ratio, whereas the induction of vegetative bud differentiation was related to a low IAA/CTK ratio.

Application of N: P Stoichiometry to Ecology Studies

Stoichiometry has long been addressed in the studies of ecosystem ecology, but it was almost ignored for a long time. Until recently, ecologists have become aware that stoichiometry could provide a new tool to study ecology from genes to the biosphere. Among this trend, N:P stoichiometry is used actively in ecological interactions since nitrogen (N) and phosphorus (P) are the two most important elements in most ecosystems. This article reviews the application of N:P stoichiometry to the studies of ecological problems at different levels, including ecosystem, community and species. Meanwhile, we also provide the cellular basis of N:P stoichiometry, identify the shortages in the use of N:P stoichiometry theory, and put forward some perspectives for future research to be conducted.

Harmful algal blooms and eutrophication: "strategies" for nutrient uptake and growth outside the Redfield comfort zone

While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.

Annual and Monthly Variations in Litter Macronutrients of Three Subalpine Forests in Western China

Macronutrients （N, P, K, Ca, Mg, and S） in litter of three primarily spruce （Picea purpurea Masters） （SF）, fir （Abies faxoniana Rehder ＆ E. H. Wilson） （FF）, and birch （Betula platyphylla Sukaczev） （BF） subalpine forests in western China were measured to understand the monthly variations in litter nutrient concentrations and annual and monthly nutrient returns via litteffall. Nutrient concentration in litter showed the rank order of Ca 〉 N 〉 Mg 〉 K 〉 S 〉 P. Monthly variations in nutrient concentrations were greater in leaf litter （LL） than other litter components. The highest and lowest concentrations of N, P, K, and S in LL were found in the growing season and the nongrowing season, respectively, but Ca and Mg were the opposite. Nutrient returns via litterfall showed a marked monthly pattern with a major peak in October and one or two small peaks in February and/or May, varying with the element and stand type, but no marked monthly variations in nutrient returns via woody litter, reproductive litter, except in May for the BF, and moss litter. Not only litter production but also nutrient concentration controlled the annual nutrient return and the monthly nutrient return pattern. The monthly patterns of the nutrient concentration and return were of ecological importance for nutrient cycling and plant growth in the subalpine forest ecosystems.

Application of an integrated methodology for eutrophication assessment:a case study in the Bohai Sea

An integrated methodology for eutrophication assessment,which integrates both water quality indicators(causative factors) and ecological response indicators(effect factors),is described.It is then applied to rank the eutrophication status of the years 2007 and 2008 in the southwest Bohai Sea.The assessment model identified that north Bohai Bay and west Laizhou Bay were the two areas with the most serious eutrophication problems in the southwest Bohai Sea.In addition,compared to that in the west Laizhou Bay,the eutrophication conditions in the north Bohai Bay was more serious in both years.Eutrophication problems such as harmful algal blooms(HABs) and low dissolved oxygen(DO) events in north Bohai Bay were frequent.The integrated method outmatched the currently used Chinese nutrient index method by definitely identifying areas with the most serious eutrophication problems,while the nutrient index method gave ambiguous results between the two years.Inclusion of both causative factors and effect factors,combining concentration,spatial coverage and frequency of indicators,as well as use of multi-season monitoring datasets in the methodology result in a more accurate,representative and useful assessment.

Nutrients distribution and trophic status assessment in the northern Beibu Gulf, China

Using historical and 2010 field data, the distribution of nutrients in the northern Beibu Gulf of China is described. There was a decreasing trend in the concentration of nutrients from the north coast to offshore waters of the northern Beibu Gulf, reflecting the influence of inputs from land-based sources. High concentrations of dissolved inorganic nitrogen （DIN） and phosphate （PO4-P） occurred mainly at Fangchenggang Bay, Qinzhou Bay, and Lianzhou Bay. Four different methods were used to assess eutrophication. The trophic status of the Beibu Gulf was characterized using the single factor, Eutrophication index （El）, Trophic index （TRIX） and Assessment of Estuarine Trophic Status （ASSETS） methods. Based on nutrient concentrations, 73.9% of DIN and 26.7% of PO4-P samples exceeded the fourth grade Seawater Quality Standard of China. Eutrophication index values varied widely, but higher levels of eutrophication were generally found in bays and estuaries. TRIX values ranged from 2.61 to 7.27, with an average of 4.98, indicating a mesotrophic and moderately productive system. A positive correlation between TRIX and harmful algal species richness and abundance was observed. The ASSETS model evaluates eutrophication status based on a Pressure-State-Response approach, including three main indices： influencing factors, overall eutrophic condition, and future outlook. The Beibu Gulf was graded as moderate using ASSETS. The single factor and Chinese nutrient index methods were considered inadequate for the assessment of trophic status. TRIX can be used as an indicator of trophic state and ASSETS showed good potential to assess eutrophication. The results of TRIX and ASSETS depend on threshold values. To establish these values, further research is required within the northern Beibu Gulf.

New Approach for Rapid Assessment of Trophic Status of Yellow Sea and East China Sea Using Easy-to-Measure Parameters

To realize potential cost savings in coastal monitoring programs and provide timely advice for marine management, there is an urgent need for efficient evaluation tools based on easily measured variables for the rapid and timely assessment of estuarine and offshore eutrophication. In this study, using parallel factor analysis(PARAFAC), principal component analysis(PCA), and discriminant function analysis(DFA) with the trophic index(TRIX) for reference, we developed an approach for rapidly assessing the eutrophication status of coastal waters using easy-to-measure parameters, including chromophoric dissolved organic matter(CDOM), fluorescence excitation–emission matrices, CDOM UV-Vis absorbance, and other water-quality parameters(turbidity, chlorophyll a, and dissolved oxygen). First, we decomposed CDOM excitation-emission matrices(EEMs) by PARAFAC to identify three components. Then, we applied PCA to simplify the complexity of the relationships between the water-quality parameters. Finally, we used the PCA score values as independent variables in DFA to develop a eutrophication assessment model. The developed model yielded classification accuracy rates of 97.1%, 80.5%, 90.3%, and 89.1% for good, moderate, and poor water qualities, and for the overall data sets, respectively. Our results suggest that these easy-to-measure parameters could be used to develop a simple approach for rapid in-situ assessment and monitoring of the eutrophication of estuarine and offshore areas.

Distribution of nutrients and eutrophication assessment in the Bohai Sea of China

Water samples were collected in 120 stations in the Bohai Sea of China to analyze the distribution of dissolved nutrients and assess the degree of eutrophication in August 2002. The result shows that the average concentration of DIN increased and the PO4-P concentration sharply decreased compared to the previous data of corresponding period. The high concentrations of DIN and PO4-P occurred in coastal waters, especially in the bays and some river estuaries, while the high concentrations of SiO3-Si in the surface and middle depth occurred in the central area of the Bohai Sea. The average ratio of DIN/PO4-P was much higher than the Redfield Ratio （16：1）. Apparently, PO4-P was one of the limiting nutrient for phytoplankton growing in the sea. The average concentrations of DON and DOP were higher than their inorganic forms. The results of eutrophication assessment show that 22.1% of all stations were classified as violating the concentration levels of the National Seawater Quality Standard （GB 3097-1997） for DIN and only 3.9% for PO4-R The average eutrophication index in the overall area was 0.21±0.22 and the high values occurred in Bohai Bay, Liaodong Bay and near the Yellow River estuary. This means that the state of eutrophication was generally mesotrophic in the Bohai Sea, but relatively worse in the bays, especially some river estuaries.

The trophic state of lake water regulates spatial-temporal variations of bloom-forming Microcystis

Although biomass variations in Microcystis and microcystin have been widely reported,few studies have addressed whether different trophic states of natural lake water affect the spatial-temporal variations in abundances of microcystin-producing Microcystis in a given bloom.In this study,we used a harmful algal bloom in Chaohu Lake,eastern China,as an example to investigate the mutual relationship between different nutrient states and environmental factors,and the impact on Microcystis.Overall,cyanobacteria and Microcystis were more abundant in the middle and western parts of the lake under high nutrients levels,while in the eastern part,nutrient concentrations were low enough to limit biomass,and their fluctuations affected the contents of toxic Microcystis.Moreover,microcystin concentration was correlated positively to nutrient levels and Microcystis biomass during bloom developing in 2013 from June to August.Temporally,the cellular content of total microcystin was lowest when the bloom peaked in intensity.Our results suggest that lake eutrophication not only results in cyanobacterial blooms,but may also increase the proportion of toxic Microcystis species and their cell-bound MCs contents(i.e.microcystin cell quotas) under mild eutrophication.The present investigation provided molecular evidence for the selection of MC-producing and non-MC-producing genotypes.The current study provides new evidence advocating the monitoring of partitions of large lakes when studying cyanobacteria and toxin-contaminated freshwaters,which will be beneficial for both water agencies and water researchers.

Removal of Nitrogen and Phosphorus from Animal and Municipal Wastewaters as Dittmarite

Phosphorus and nitrogen are known causes of eutrophication in rivers, lakes streams and estuaries. The sources of these nutrients are diverse and they include chemical fertilizers, CAFOs （Confmed Animal Feeding Operations）, land application of animal and municipal as well as industrial wastewaters. Application of manure slurries to crop land beyond allowable limits could result in high levels of phosphorus and nitrogen in runoff that negatively impact aquatic animals. Municipal wastewater treatment plants are setup to remove these nutrients from domestic and industrial wastewater through a network of treatment processes. Controlling the discharge of phosphorus and nitrogen in wastewater is a key factor in preventing eutrophication. This paper presents work done to enhance a chemical precipitation process that removes over 90% of dissolved phosphorus and nearly 20% of dissolved nitrogen from both synthetic and municipal wastewaters. The objective of the study is to remove nitrogen and phosphorus from wastewater as dittmarite, a value-added mineral fertilizer found in nature. A laboratory procedure was developed that generated significant quantities of dittmarite from various wastewaters. Pure dittrnarite contains nitrogen, phosphorus and magnesium in approximate molar ratios of 1：1.2：1.2 that can support plant growth. It is produced as a wet precipitate from chemical reactions that occur in the wastewater treatment process; it can be dried for proper handling and utilization. Municipal wastewater treatment plants, high volume fish producers, CAFOs and individual rural homeowners could all benefit from this technology for on-site removal of nitrogen and phosphorus from produced wastewaters.

Diet and feeding ecology of invasive icefish Neosalanx taihuensis in Erhai Lake,a Chinese plateau mesoeutrophicated lake

A comprehensive study of the invasive icefish Neosalanx taihuensis feeding ecology in Erhai Lake was conducted from November 2009 to October 2010. Prey items in the guts of the icefish sampled varied significantly according to season. This finding suggests a relationship between fluctuations in available prey in the environment and selective feeding by icefish. N. taihuensis preferred large-sized zooplankton, such as Daphnia and calanoids. Additionally, the gut fullness values differed significantly （P〈0.001） among sampling times. To compare the values at different times, samples were taken over a 24 h period every 2 months for the entire year. The feeding activities of the fish were concentrated either in the morning （8：00） and/or at dusk （20：00）, except in September 2010. This finding can be explained primarily by the variation in optimum light intensity. Daily N. taihuensis zooplankton consumption varied significantly, both diurnally and among seasons. The daily consumption values ranged from 0.089 to 0.237 g （wet weight） per 100 g wet fish weight in temperatures between 11.50℃ and 24.68℃. This is the first report of diel feeding periodicity and daily food consumption of icefish in their invaded ecosystems.

Coastal Sea Water Quality of Nha Trang Bay, Khanh Hoa, Viet Nam

Nha Trang Bay is famous not only because of its beauty, but also of the biodiversity values, especially coral reefs. Thus, the sea water quality monitoring systems are necessary for effective and available managements to protect the ecosystems and for sustainable development. There have been several monitoring systems here but they have been done separately and unconnectedly. This research was done to take an overview and access the status and changes of water quality from 2007-2014. The data obtained rainy seasons over the years showed a quite good environment here. The environment changes were also monitored and there were some changes between seasons and over years, decreasing, increasing, or unobvious trends. However, the difference was not so much; and there was not the sign of environmental degradation in the bay from 2007 to 2014. Besides, the stoichiometric nutrients limitations were initially assessed. Since Si ratios here were always higher compared to N and P, there was not increased potential for non-diatom algal blooms. Together with the recorded nutrients concentration data, it can be said that there was no evidence of eutrophication in the bay. Although there was partial contamination of some parameters at few moments, the sea water quality of Nha Trang bay was still in a good condition （according to Vietnamese and ASEAN criteria）.

Relative abundance of biotic communities of plankton and zoobenthos in three ox-bow lakes of Eastern India

We made comparative studies of three tropical ox-bow lakes in India with different trophic states.The species number of zooplanktons was negatively correlated with the degree of water eutrophication,and lakes of similar trophic status had higher similarity of species.The most significant differences of species composition were observed with rotifers and zoobenthos.The density and biomass of phytoplankton,rotifers,oligochaetes and chironomids tended to increase with increasing nutrients.We observed a significant difference of dominant species in different waters,especially the eutrophic lake,which was dominated by a few species of oligochaetes.The abundance of Tanypus bilobatus showed a highly significant correlation with the degree of eutrophication.Rotifers and zoobenthos showed considerably lower biodiversity in the eutrophic lake.

Nutrient effects of broodstocks on the larvae in Patinopecten yessoensis

Patinopecten yessoensis is a commercial valuable species. This study deals with the effect of nutrient effects of the broodstock(mainly ovaries) on the larvae. Concentrations of total carbohydrate, total protein and total lipid in the gonads of P. yessoensis from three Hatcheries(Hatchery 1, Hatchery 2, and Hatchery 3) were determined before and after spawning. The relationship between the nutrient concentration in ovaries before spawning(BC) and that of larvae(LC) was assessed as well as the change in nutrient levels in ovaries after spawning(DC). Results indicate that the BC of total carbohydrate(7.66%) and total lipid(14.48%) in ovaries were significantly higher than in testes(5.20%, 5.20% respectively), whereas the BC of total protein in the ovaries was lower(61.76%) than in the testes(81.67%). The different gonadal composition suggests the different nutrient demands between male and female broodstocks in breeding season. P atinopecten yessoensis gonads contained a higher proportion of lipids, in comparison to other bivalves, which might be a response to the low ambient water temperatures. Further analysis of fatty acids showed that the concentrations of n-3PUFA, EPA and DHA in larvae(LC) were positively correlated with BC and DC, indicating the significant nutrient influence of broodstocks on the larvae. As these fatty acids are important in metabolism, and have been demonstrated to be influential to the viability of the larvae, larval growth and the settlement, spat growth, and juvenile survival in many bivalves, they could possibly be used as indexes to evaluate, and predict condition of broodstocks and larvae.

External versus Internal Loads of Nutrients of an Urban Eutrophic Tropical Reservoir （Southeastern Brazil）

This study aimed to evaluate the external and internal fluxes of nutrients of an urban eutrophic reservoir （lbirit6 reservoir, SE-Brazil）. External loads were estimated in the tributaries （Pintados and Ibirit6 creeks） through nutrient concentrations and discharge measurements. Using Fick＇s law, internal loads were estimated in the reservoir from fluxes across sediment-water interface from nutrient concentration gradients between the pore water and the water. The Ibirit6 creek （urban sewage recipient） contributes with 72%-47% of ammonium （NH4^＋） and 100%-8% of SRP （soluble reactive phosphorus） of the total quantity entering the reservoir, whereas the Pintados creek （oil refinery effluent recipient） contributions are 20%-19% and 44%-100%, respectively. Despite the high external loads （130 and 2.2 ton-yr^-1 of NH4＋ and SRP, respectively）, internal loads （average flux of 120 and 2 mg·cm^-2yr^-1, respectively） correspond to 25% of the total external loads which may sustain a high productivity in the reservoir for a long time even if the external loads are controlled. The stocks of ammonium and SRP of the interstitial water （100 cm of sediment） would be released to the water in six years and five months, respectively, The release time would be extremely larger （〉 3,000 years） considering the stocks of total N and bioavailable P.

Phosphorus Fractions in Water and Sediment and Their Correlations in Hengshui Lake, China

Sediment is a principal reservoir which accumulates and releases the pollutants. It is an important way of nutrients releasing from pore water of sediments to overlying water across the sediment-water interface. Five sampling sites were selected in the Hengshui Lake. Overlying water and sediments were collected in each of them. The phosphorus fractions and their relationships were analyzed. The results showed that the change of the total phosphorus （TP） in sediment was similar to that of the total dissolved phosphorus （TDP） and soluble orthophosphate （PO4^3-） in pore water. The concentrations of PO4^3- in pore water were higher than those in overlying water, reflecting a possible diffuse trend for PO4^3-P in the five zones of Hengshui Lake. It is indicated that phosphorus and other nutrients will be transferred from sediment to pore water and then to overlying water, which can lead to lake eutrophication.