本文選題：濕地 + 水深��； 參考：《東北林業(yè)大學(xué)》2015年碩士論文

【摘要】：基底是濕地植物的支撐者,同時也是微生物及底棲動物活動的場所,基底條件的改善是濕地生態(tài)修復(fù)的基礎(chǔ),而基底形態(tài)優(yōu)化則是基底條件改善的重要舉措。本文首先以典型凹形基底濕地為例研究了基底形態(tài)對濕地水體及底泥中營養(yǎng)鹽分布的影響,研究發(fā)現(xiàn)濕地水體及沉積物中營養(yǎng)鹽分布是不均勻的,其分布規(guī)律與上覆水深度有關(guān)。水體ρ(TN)和ρ(TP)隨著上覆水深度的增加(基底高程的降低)呈現(xiàn)先降低再升高的趨勢,在水深為30-50 cm位置處的水體中達到最低值,而表層底泥中w(TP)和w(TN)隨著上覆水深度增加呈現(xiàn)升高趨勢,在水深為70-80 cm位置處底泥中營養(yǎng)鹽濃度最高。利用流體動力學(xué)軟件Fluent對進入濕地的水體流態(tài)進行分析得出,濕地營養(yǎng)鹽的分布受水流流態(tài)影響較大,而水體流態(tài)則受基底形態(tài)影響。然后,以典型凹形基底濕地為例研究了基底形態(tài)對暴雨徑流污染凈化特征的影響。營養(yǎng)鹽隨暴雨徑流進入濕地,引起濕地水體營養(yǎng)鹽濃度迅速升高。暴雨結(jié)束初期,濕地系統(tǒng)對水體中營養(yǎng)鹽的削減以物理沉降為主,其后,濕地系統(tǒng)對水體中營養(yǎng)鹽的削減以生物降解為主,這兩個過程均受到基底理化條件的影響,而基底理化條件由基底形態(tài)結(jié)構(gòu)引起。就濕地系統(tǒng)內(nèi)部而言,存在“高效凈化區(qū)”和“低效凈化區(qū)”,基底的起伏變化引起濕地上覆水深度的變化,進而導(dǎo)致基底理化指標(biāo)的差異,從而影響營養(yǎng)鹽的凈化效率。最后,在實驗室內(nèi)模擬構(gòu)建5種不同形態(tài)基底(斜面型、平面型、凹面型、凸面型及多自然型基底),在典型水深(40cm)的條件下,研究了不同基底形態(tài)對“水體-底泥”系統(tǒng)營養(yǎng)鹽的去除效果。研究發(fā)現(xiàn)不同基底形態(tài)實驗組系統(tǒng)對總氮的去除率依次為28.84%、25.22%、27.07%、31.23%、35.23%；對總磷的去除率基本相同,只有略微差別,是由水生植物的攝取造成的。濕地基底形態(tài)的差異,導(dǎo)致底泥一水界面的有效比表面積不同,從而影響了基底生物膜的附著空間和底泥與水體交換程度,最終也會影響濕地系統(tǒng)對營養(yǎng)鹽的凈化效果。另外,基底形態(tài)結(jié)構(gòu)還影響基底光的強弱分布,進而影響了水生植物的發(fā)育及生長,也導(dǎo)致了濕地系統(tǒng)對營養(yǎng)鹽的去除效果的差異。
[Abstract]:The substrate is not only the support of wetland plants, but also the site of microorganism and benthic animal activity. The improvement of basal condition is the basis of wetland ecological restoration, and the optimization of basal morphology is an important measure to improve the base condition. In this paper, a typical concave base wetland is taken as an example to study the effect of substrate morphology on nutrient distribution in wetland water and sediment. It is found that the distribution of nutrient in wetland water and sediment is not uniform. Its distribution is related to the overlying water depth. With the increase of overlying water depth (decrease of basal elevation), the water body 蟻 (TNN) and 蟻 TPS) decreased first and then increased, and reached the lowest value in the water body where the water depth was 30-50 cm. However, the content of TP and TNN in the surface sediment increased with the increase of the overlying water depth, and the highest concentration of nutrients was found in the sediment at a depth of 70-80 cm. By using the fluid dynamics software Fluent to analyze the water flow pattern, it is concluded that the distribution of nutrients in the wetland is greatly affected by the water flow pattern, while the water flow pattern is affected by the basal morphology. Then, taking typical concave wetland as an example, the effects of substrate morphology on the pollution purification characteristics of rainstorm runoff were studied. The nutrient concentration of wetland water increased rapidly with the rainstorm runoff coming into the wetland. At the beginning of torrential rain, the reduction of nutrient in water by wetland system was mainly physical sedimentation, and then the reduction of nutrient in water by wetland system was mainly biodegradable. These two processes were affected by the physical and chemical conditions of substrate. The physical and chemical conditions of the substrate are caused by the morphological structure of the substrate. As far as the wetland system is concerned, there are "high efficiency purification areas" and "low efficiency purification areas". The fluctuation of the base causes the change of the overlying water depth of the wetland, and then leads to the difference of the physical and chemical indexes of the substrate, thus affecting the purification efficiency of the nutrient. Finally, five different types of substrates (inclined, plane, concave, convex and polynatural) were constructed in laboratory under typical water depth of 40 cm. The effect of different substrate morphology on nutrient removal in water-sediment system was studied. The results showed that the removal rate of total nitrogen in the experimental group with different substrate morphology was 28.84 ~ 25.22 ~ 27.07 and 31.2323 ~ 35.233.The removal rate of total phosphorus was basically the same and only slightly different, which was caused by the uptake of aquatic plants. The difference of substrate morphology leads to the difference of the effective specific surface area of the interface between sediment and water, which affects the adhesion space of the substrate biofilm and the exchange degree between sediment and water, and finally affects the purification effect of the wetland system on nutrient salt. In addition, the morphological structure of the substrate also affects the distribution of the intensity and intensity of the substrate light, thus affecting the development and growth of aquatic plants, which also leads to the difference of nutrient removal efficiency in the wetland system.
【學(xué)位授予單位】：東北林業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X171.4

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