【摘要】：濕地水文控制和維持濕地生態(tài)系統(tǒng)的結(jié)構(gòu)和功能,水文狀態(tài)的改變必然會(huì)對(duì)土壤呼吸速率產(chǎn)生影響。全球氣溫升高對(duì)濕地生態(tài)系統(tǒng)的碳循環(huán)也會(huì)產(chǎn)生影響。因此,有必要研究水位和增溫對(duì)濕地土壤呼吸的影響及其影響機(jī)制。本文以上海市崇明東灘濱海圍墾濕地為研究對(duì)象,于2014年4月到10月,測(cè)定了不同水位梯度以及增溫和不增溫處理下的土壤呼吸(RST)、根呼吸(RSR)、無根土壤呼吸(RSS)和表層凋落物呼吸(RSL),并測(cè)定了土壤溫濕度、理化性質(zhì)以及生物因子,研究了水位和增溫對(duì)土壤呼吸及其組分的影響,并探討了水位和增溫對(duì)土壤呼吸的影響機(jī)制,以期為預(yù)測(cè)該地區(qū)在不同水位調(diào)控以及增溫背景下的濕地固碳能力提供參考,并為濕地的科學(xué)管理提供基礎(chǔ)數(shù)據(jù)和依據(jù)。研究結(jié)果表明：1、水位對(duì)土壤呼吸及其組分的影響(1)不同水位梯度下,土壤呼吸及其組分日動(dòng)態(tài)呈單峰曲線,表現(xiàn)為中水位低水位高水位,最大值出現(xiàn)在12：00-14：00,最小值出現(xiàn)在00：00-03：00。土壤呼吸及其組分季節(jié)變化明顯,除RSL呈單峰曲線外,其它組分及RST都呈多峰曲線。生長(zhǎng)季低、中、高水位土壤總呼吸平均值分別為3.14、3.48、2.16,低水位顯著大于高水位,但比中水位小,證明隨著水位降低,土壤呼吸并非一直增大,而是水位下降超過一定閾值后,土壤呼吸會(huì)再度受到抑制。(2)不同水位梯度下,土壤呼吸及其組分日動(dòng)態(tài)與土壤5cm溫度均具有顯著指數(shù)關(guān)系(P0.05),土壤體積含水量與土壤呼吸相關(guān)性不顯著(P0.05)。整個(gè)生長(zhǎng)季,土壤呼吸及其組分季節(jié)動(dòng)態(tài)與土壤溫度無顯著關(guān)系。地面無積水時(shí),不同水位梯度下RST與土壤溫度均具有顯著指數(shù)關(guān)系(P0.05),各組分中只有RSR與土壤溫度具有顯著指數(shù)關(guān)系(P0.05),土壤溫度可以解釋RST和RSR季節(jié)變化的51.9%-68.8%和46.9%-58.3%；地面積水時(shí),土壤呼吸及其組分與土壤溫度無顯著相關(guān)性(P0.05)。(3)不同水位梯度下,土壤呼吸各組分貢獻(xiàn)率大小順序均為：RSRRSS RSL,且三者之間差異顯著(P0.05),但水位梯度對(duì)三者貢獻(xiàn)率無顯著影響(P0.05)。(4)低、中、高水位RST的Q10值分別為1.51、2.51、1.63,RSR的Q10值分別是1.70、3.73、1.85,表明中水位的土壤總呼吸和根呼吸的溫度敏感性最強(qiáng),且根呼吸溫度敏感性強(qiáng)于土壤總呼吸。2、增溫對(duì)土壤呼吸及其組分的影響(1)在季節(jié)尺度上,OTC升溫效果明顯,空氣溫度平均增加了1.61±0.16℃(P0.01),土壤5cm溫度平均升高了1.09±0.15℃(P0.01)。在日尺度上,增溫效果只出現(xiàn)在白天,OTC內(nèi)夜間土壤溫度比CK低。(2)CK和OTC的土壤呼吸及其組分日動(dòng)態(tài)均呈單峰曲線,峰值出現(xiàn)時(shí)間基本一致�？傮w上而言,增溫處理日均呼吸速率大于對(duì)照(P0.05)。兩種處理?xiàng)l件下土壤呼吸及其組分均具有明顯的季節(jié)變化,除RSL呈單峰曲線外,其它組分及RST都呈多峰曲線。生長(zhǎng)季OTC顯著促進(jìn)了RST、RSR、RSS(P0.05)。(3)兩種處理下,土壤呼吸及其組分日動(dòng)態(tài)與土壤5cm溫度均具有顯著指數(shù)關(guān)系(P0.05),整個(gè)生長(zhǎng)季土壤呼吸及其組分季節(jié)動(dòng)態(tài)與土壤溫度無顯著關(guān)系(P0.05)。地面無積水時(shí),增溫處理RST、RSR、RSS與土壤溫度均具有顯著指數(shù)關(guān)系(P0.05),對(duì)照處理RST和RSR與土壤溫度具有顯著指數(shù)關(guān)系(P0.05)；地面積水時(shí),土壤呼吸及其組分與土壤溫度均無顯著相關(guān)性(P0.05)。(4)增溫和對(duì)照處理下,土壤呼吸各組分貢獻(xiàn)率大小順序均為：RSRRSSRSL,且三者之間差異顯著(P0.05),但增溫對(duì)各組分貢獻(xiàn)率無顯著影響(P0.05)。(5)OTC處理下RST、RSR、RSS的Q10值分別為2.86、3.25、2.61,CK處理下RST和RSR的Q10值分別為2.51和3.73,表明增溫提升了土壤總呼吸的溫度敏感性,同時(shí)削弱了根呼吸的溫度敏感性；根呼吸溫度敏感性強(qiáng)于土壤總呼吸。
[Abstract]:The hydrological control of the wetland and the structure and function of the wetland ecosystem will have an effect on the respiration rate of the soil. The global temperature rise will also have an impact on the carbon cycle of the wetland ecosystem. Therefore, it is necessary to study the effect of water level and temperature increase on the respiration of wetland soil and its influencing mechanism. Soil respiration (RST), root respiration (RSR), non-root soil respiration (RSS) and surface litter respiration (RSL) under different water level gradients and temperature and non-warming treatments were measured in the coastal reclamation wetland of Dongtan, Chongming, Shanghai, from April to October,2014. The effects of water level and temperature on the respiration of soil and its components were studied and the effects of water level and temperature on the respiration of soil were discussed. So as to provide reference for predicting the carbon sequestration capacity of the wetland under different water level regulation and temperature increasing background, and provide the basic data and the basis for the scientific management of the wetland. The results show that:1. The effect of water level on the respiration of soil and its components (1) The soil respiration and its composition day have a unimodal curve under different water level gradients. The results show that the maximum water level and the maximum value of the medium water level are in the range of 12:00-14:00, and the minimum value is at 00:00-03:00. In addition to the unimodal curve of RSL, the other components and the RST showed a multi-modal curve. The average respiration average of the middle and high water-level soil is 3.14, 3.48, 2.16, and the low water level is significantly higher than that of the high water level, but the water level is small, and the soil respiration is not always increased with the decrease of the water level, but the soil respiration will be inhibited again after the water level drops more than a certain threshold. (2) Under different water-level gradients, the soil respiration and its composition date had a significant exponential relationship with the soil's 5 cm temperature (P0.05), and the soil volume water content was not significant with the soil respiration (P0.05). There was no significant relationship between the soil respiration and the soil temperature during the whole growing season. There was a significant exponential relationship between the RSR and the soil temperature in different water-level gradients (P0.05). The soil temperature could explain the 51.9%-68.8% and 46.9%-58.3% of the changes in the RST and RSR seasons. There was no significant correlation between the soil respiration and its components and soil temperature (P0.05). (3) The rate of contribution of each component in the soil respiration was: RSRRSS RSL, and the difference between the three levels was significant (P0.05), but the water level gradient had no significant effect on the contribution rate of the three components (P0.05). (4) The Q10 value of the low, medium and high water level RST is 1.51, 2.51, 1.63, and the Q10 value of the RSR is 1.70, 3.73, 1.85, respectively. The effect of increasing the temperature on the respiration and the components of the soil (1) on the seasonal scale was obvious, the air temperature increased by 1.61-0.16 鈩，

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