Succession and seasonal variation in epilithic biofilms on artificial reefs in culture waters of the sea cucumber Apostichopus japonicus

Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the AsiaPacific region, particularly in China, artificial reefs are commonly used in the commercial farming of sea cucumbers. However, few studies have examined the epilithic biofilms on the artificial reefs. To gain a better understanding of the succession of epilithic biofilms and their ecological processes in sea cucumber culture waters, two experiments were conducted in culture waters of the sea cucumber Apostichopus japonicus in Rongcheng, China, using artificial test panels. On the test panels of succession experiment, more than 67 species were identified in the biofilms. On the test panels of seasonal variation experiment, more than 46 species were recorded in the biofilms. In both experiments, communities of epilithic biofilms were dominated by diatoms, green algae and the annelid Spirorbis sp. In the initial colonization, the dominant diatoms were Cocconeis sp., Amphora spp. and Nitzschia closterium in June, which were succeeded by species of Navicula, Cocconeis and Nitzschia(July to September), and then by Licmophora abbreviata, Nitzschia closterium and Synedra spp. in the following months. A diatom bloom in the autumn and filamentous green algae burst in the summer were also observed. Ecological indices well annotated the succession and seasonal changes in epilithic communities. Multidimensional scaling(MDS) analysis found significant differences in diatom community composition among months and seasons. Fast growth of biofilms was observed in the summer and autumn, whereas the biomass of summer biofilms was largely made up of filamentous green algae. Present results show that the components of epilithic biofilms are mostly optimal foods of A. japonicus, suggesting that biofilms on artificial reefs may contribute important nutritional sources for sea cucumbers during their growth seasons. Future works should include quantitative determination of the contribution of epilithic biofilms to the diet of A. japonicus, potential roles of epilithic biofilms in regulating the water quality of sea cucumber ponds, and the regulation of epilithic biofilms in sea cucumber culture ponds.

Propagation of Abies beshanzuensis by Water Cultured Medium

[Objective] The experiment aimed to explore the influences of phytohormones (ABT and IAA) and nutrient solution on rooting of Abies beshanzuensis M.H.Wu by water cultured medium. [Method] The Abies beshanzuensis M.H.Wu were treated by water (CK), 10 mg/L ABT+ water, 10 mg/L IAA+ water, 10 mg/L ABT+ hoagland solution, 10 mg/L IAA+ hoagland solution, then the rooting process was observed and the formation rate of callus, rooting rate, number of rooting, and root length were investigated and analyzed. [Result] ABT and IAA had obvious influences on callus induction, rooting rate and the number of root of Abies beshanzuensis M.H.Wu by water culture, so they were suitable to be used in water propagation of Abies beshanzuensis M.H.Wu. The treatments of phytohormones had no regular influences on the longest root length and average root length. The nutrient solutions would not generate obvious influence on propagation of Abies beshanzuensis M.H.Wu at firstly stage, but they generated influence on root growth after rooting. [Conclusion] The research provided new ideas for propagation of Abies beshanzuensis M.H.Wu, which could make it out of endangerment situation quickly.

Carry forw ard Soil and Water Ecological Culture and Build Rich and Beautiful Home

The most directly expressions of the relationships between human and nature lie in the relationships between human and water,human and soil（ stone）,human and vegetation（ plant）. Water,soil and vegetation are interdependent,restricted coexisted and developed from one another,which are integrated and correlated. The history of human＇s survival and development on the earth is one related continuously with water,soil（ stone）,vegetation（ plant）,which involves with the protection and reasonable utilization of water,soil and vegetation resources（ also known as soil and water ecological resources）,and it has summarized and accumulated abundant culture concerned with the harmonious coexistence of human with water,soil and vegetation,which is the soil and water ecological culture. All peoples of China have accumulated rich soil and water ecological culture in the long term,such as integrated view of nature,nature admiring,nature praising,nature protection and reasonable utilization of nature. It is especially important and urgent in the current times to carry forward soil and water ecological culture.

Effect of CO_2 Concentration on Nitrogen Metabolism of Winter Wheat

Hoagland＇s solution was used as water culture medium to study the effect of CO2 concentration on nitrate metabolism of wheat under natural light and light-shaded conditions. NO3^-N, NH4^＋-N, nitrate reductase activity, total uptake N by wheat plants during solution cultural period and total N in plants were determined for comprehensive evaluation of the effect. Results showed that under both natural light and light-shaded conditions, addition of CO2 increased NO3^-N uptake and its assimilative capabilities by plants. However, there were some difference between shoots and roots. With increase of CO2 concentration, the concentration of NO3^-N and NH4^＋-N as well as nitrate reductase activity were all decreased for shoots while the difference was not so distinct in roots, and the nitrate reductase activity was not decreased, but increased. Since NO3^-N uptake by plants from the solution and the total N in plants were much higher by CO2 addition, it may be concluded that addition of CO2 has resulted in rise of nitrate absorption, assimilation and metabolism of wheat.

Thoughts on the Construction of Urban Water Ecological Civilization in Northeast China

Based on the ongoing construction of water ecological civilization in China,the connotation and specific requirements of ecological civilization and ecological civilized city are analyzed in detail. Combining with present situation and characteristics of water resources,water environment and water culture in Northeast China,the main contents to be considered in the construction of water ecological civilization in Northeast China are discussed,which could provide the reference for construction of water ecological civilization city.

Enlightenment and Reflection on the Leap of "Butterfly Change" in Cultural Features of the Ancient Seawall in the New Era

At first, the overview and value of cultural relics of Xiaoshao Seawall were introduced, and then the confusion of daily management and comprehensive improvement were analyzed. Finally, the enlightenment and reflection on the "butterfly change" of the seawall were discussed.