生态环境学报
生態環境學報
생태배경학보
ECOLOGY AND ENVIRONMENT
2015年
7期
1103-1107
,共5页
徐国良%王敏%张卫信%夏汉平%王嘉珊%吴志峰
徐國良%王敏%張衛信%夏漢平%王嘉珊%吳誌峰
서국량%왕민%장위신%하한평%왕가산%오지봉
跳虫%同位素%碳循环
跳蟲%同位素%碳循環
도충%동위소%탄순배
collembola%stable isotope%carbon transformation
土壤动物在土壤碳库中发挥着重要的作用，但长期以来受技术手段的限制，其作用过程及贡献程度仍不清楚。该研究通过室内微宇宙实验，利用稳定碳同位素标记凋落物和模式跳虫实验种（Folsomia Candida）探索了土壤动物在碳循环中的作用。试验设置了3个处理：对照土壤、土壤加标记凋落物、土壤加标记凋落物和跳虫，每处理设4个重复，分别在实验开始的第7、21、63天进行破坏性取样。研究结果发现，凋落物新碳可以很快进入土壤食物网。试验跳虫δ13C 原始值为-9.91‰±0.08‰，经过7天的培养，跳虫体内的δ13C值达到522.70‰，表明跳虫能在短时间内高效同化来自凋落物的新碳；土壤微生物群落也显著地同化了凋落物新碳，添加凋落物后微生物PLFAs δ13C值极显著升高，这种效应在试验初期尤其显著；同时，研究发现在添加跳虫的处理中，微生物δ13C 比无跳虫处理的极显著升高，反映跳虫的存在和活动对微生物有积极的能动作用，增加微生物对凋落物新碳的同化效率。虽然7 d后发现凋落物新碳明显进入了土壤，然而添加跳虫处理的土壤δ13C显著低于没有加跳虫的，说明跳虫的活动可能促使了更多新C释放出土壤，从而降低了土壤的δ13C值。不同处理之间累计呼吸量存在显著差异，有凋落物和跳虫存在的处理极显著高于对照处理，表明实验处理都显著地增加了系统 CO2通量；通过对C来源的同位素解析，发现试验初期（21 d）有85%以上的C都来自凋落物新碳，表明初期凋落物新C大量释放；但随着凋落物分解的进行或跳虫活动的增强，土壤C的利用效率逐步增加，使得通量中土壤C的比例逐渐增加。本研究通过比较完善的控制实验明确证实，在土壤动物和微生物的作用下，凋落物新C可以很快进入碳循环，但新C也很容易通过呼吸作用释放回到大气，尤其在初期，绝大部分排放的 CO2都源自新 C。土壤跳虫在食物网中的作用明显，对土壤微生物具有显著的调控作用。
土壤動物在土壤碳庫中髮揮著重要的作用，但長期以來受技術手段的限製，其作用過程及貢獻程度仍不清楚。該研究通過室內微宇宙實驗，利用穩定碳同位素標記凋落物和模式跳蟲實驗種（Folsomia Candida）探索瞭土壤動物在碳循環中的作用。試驗設置瞭3箇處理：對照土壤、土壤加標記凋落物、土壤加標記凋落物和跳蟲，每處理設4箇重複，分彆在實驗開始的第7、21、63天進行破壞性取樣。研究結果髮現，凋落物新碳可以很快進入土壤食物網。試驗跳蟲δ13C 原始值為-9.91‰±0.08‰，經過7天的培養，跳蟲體內的δ13C值達到522.70‰，錶明跳蟲能在短時間內高效同化來自凋落物的新碳；土壤微生物群落也顯著地同化瞭凋落物新碳，添加凋落物後微生物PLFAs δ13C值極顯著升高，這種效應在試驗初期尤其顯著；同時，研究髮現在添加跳蟲的處理中，微生物δ13C 比無跳蟲處理的極顯著升高，反映跳蟲的存在和活動對微生物有積極的能動作用，增加微生物對凋落物新碳的同化效率。雖然7 d後髮現凋落物新碳明顯進入瞭土壤，然而添加跳蟲處理的土壤δ13C顯著低于沒有加跳蟲的，說明跳蟲的活動可能促使瞭更多新C釋放齣土壤，從而降低瞭土壤的δ13C值。不同處理之間纍計呼吸量存在顯著差異，有凋落物和跳蟲存在的處理極顯著高于對照處理，錶明實驗處理都顯著地增加瞭繫統 CO2通量；通過對C來源的同位素解析，髮現試驗初期（21 d）有85%以上的C都來自凋落物新碳，錶明初期凋落物新C大量釋放；但隨著凋落物分解的進行或跳蟲活動的增彊，土壤C的利用效率逐步增加，使得通量中土壤C的比例逐漸增加。本研究通過比較完善的控製實驗明確證實，在土壤動物和微生物的作用下，凋落物新C可以很快進入碳循環，但新C也很容易通過呼吸作用釋放迴到大氣，尤其在初期，絕大部分排放的 CO2都源自新 C。土壤跳蟲在食物網中的作用明顯，對土壤微生物具有顯著的調控作用。
토양동물재토양탄고중발휘착중요적작용，단장기이래수기술수단적한제，기작용과정급공헌정도잉불청초。해연구통과실내미우주실험，이용은정탄동위소표기조락물화모식도충실험충（Folsomia Candida）탐색료토양동물재탄순배중적작용。시험설치료3개처리：대조토양、토양가표기조락물、토양가표기조락물화도충，매처리설4개중복，분별재실험개시적제7、21、63천진행파배성취양。연구결과발현，조락물신탄가이흔쾌진입토양식물망。시험도충δ13C 원시치위-9.91‰±0.08‰，경과7천적배양，도충체내적δ13C치체도522.70‰，표명도충능재단시간내고효동화래자조락물적신탄；토양미생물군락야현저지동화료조락물신탄，첨가조락물후미생물PLFAs δ13C치겁현저승고，저충효응재시험초기우기현저；동시，연구발현재첨가도충적처리중，미생물δ13C 비무도충처리적겁현저승고，반영도충적존재화활동대미생물유적겁적능동작용，증가미생물대조락물신탄적동화효솔。수연7 d후발현조락물신탄명현진입료토양，연이첨가도충처리적토양δ13C현저저우몰유가도충적，설명도충적활동가능촉사료경다신C석방출토양，종이강저료토양적δ13C치。불동처리지간루계호흡량존재현저차이，유조락물화도충존재적처리겁현저고우대조처리，표명실험처리도현저지증가료계통 CO2통량；통과대C래원적동위소해석，발현시험초기（21 d）유85%이상적C도래자조락물신탄，표명초기조락물신C대량석방；단수착조락물분해적진행혹도충활동적증강，토양C적이용효솔축보증가，사득통량중토양C적비례축점증가。본연구통과비교완선적공제실험명학증실，재토양동물화미생물적작용하，조락물신C가이흔쾌진입탄순배，단신C야흔용역통과호흡작용석방회도대기，우기재초기，절대부분배방적 CO2도원자신 C。토양도충재식물망중적작용명현，대토양미생물구유현저적조공작용。
Terrestrial carbon cycle is one of the key issues in the world. Soil fauna play essential roles in soil ecosystem which is the largest terrestrial carbon sink. However, both the contributions of soil fauna to carbon transformation and the underlying mechanisms are still unclear. The isotope technology provided an useful method to quantify the key processes in soil food web and material cycling. In this study,13C-labeled leaf litter was used to investigate the effect of the Collembola (Folsomia Candida) on carbon transformation in laboratory microcosms. Three treatments were set up: (1) soil (control, S), (2) soil and labeled litter (SL), and (3) soil, labeled litter and Collembola (SLC). Each treatment has four replicates. These microcosms were destructively sampled on day 7, 21, 63 after the experiment initiation. The results showed that litter-derived C was incorporated into soil biota rapidly. The originalδ13C values of Collembola was -9.91‰±0.08‰, and it reached 522.70‰ after 7 days of incubation indicating that Collembola could efficiently assimilate this newly introduced litter-derived C. Similarly, theδ13C values in PLFAs increased significantly, especially at the initial experimental stage. In addition, the presence of Collembola significantly promoted the PLFAsδ13C suggesting that Collembola could accelerate the microbial assimilation of litter carbon. Unexpectedly, treatment SLC exhibited significantly lowerδ13C values than treatment SL. This may indicate that the presence of Collembola stimulated the release of newly metabolized litter C. Both of the treatments stimulated CO2 flux significantly. By C isotope analysis, over 85% of the mineralized C derived from litter at the initiation state (21 days), demonstrating that new C from fresh litter tended to release back to atmosphere with active soil biota. Thereafter, the contribution of soil-derived C to the CO2 emission increased. This study proved that new C from litter could participate in soil C cycling rapidly, especially in systems with active soil biota. While, the newly introduced litter C was also readily to be respired as CO2. In spite of the small size, Collembola had a priming effect on microbes in the litter-soil environment and, thus, contributed to the functioning of soil food web.
