【作者】 张明亮；

【导师】 方建光；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生态学， 2011， 博士

【摘要】 海洋是地球表面第一大活跃碳库,它极大调节了全球气候变化。海洋碳循环也因此成为全球碳循环过程中最为关键的一个环节。生物在海洋碳循环中起了非常重要的作用,海洋碳循环“溶解度泵”、“生物泵”、“碳酸盐泵”的三个过程是在生物的直接或间接作用下完成的。在近海海区,其生产力远远高于远海,生物作用更加强烈,生物对碳循环的影响也就更加突出。特别是近海贝藻养殖区的存在,其高密度、高强度的生物作用必将对近海碳循环产生深远影响。目前全球大洋碳循环的格局已经探明,但对近海碳循环的研究仍存在许多问题。对养殖生物活动在近海碳循环中作用的认识,能够有助于加深人类了解近海碳循环的过程。因此,本文选取我国主要贝类养殖种栉孔扇贝作为研究对象,采用“Alkalinity anomaly technique”的方法测定了栉孔扇贝温度、盐度变化和海洋酸化对其呼吸、钙化的影响,探讨分析了可能对近海碳循环产生的影响;同时通过室内实验模拟了贝类养殖、藻类养殖、贝藻混养对海水二氧化碳系统以及碳循环过程“溶解度泵”的影响。主要结果如下:1.栉孔扇贝的钙化和呼吸活动受盐度影响显著。钙化率在盐度15-25范围内呈上升趋势,后随盐度上升而下降。呼吸率在盐度15-25范围内上升,25-35范围内下降。钙化率与呼吸率均在盐度25达到最高值,分别为0.33±0.02μmol.FWg^-1.h^-1 （钙化率）、2.32±0.10μmol.FWg^-1.h^-1 （碳呼吸）、2.87±0.14μmol.FW g^-1.h^-1（氧呼吸）,此时通过钙化和呼吸活动向环境释放CO2也最强烈。2.栉孔扇贝的钙化率和呼吸率随着温度的升高而升高,钙化率、CO2呼吸率RC和耗氧率RO都在5℃最低,分别为0.19±0.01μmol.FWg^-1.h^-1、1.38±0.06μmol.FWg^-1.h^-1、1.64±0.11μmol.FWg^-1.h^-1 ;在25℃最高,分别为0.39±0.02μmol.FWg^-1.h^-1、5.44±0.29μmol.FWg^-1.h^-1、6.34±0.33μmol.FWg^-1.h^-1。随着温度的升高通过钙化和呼吸活动向环境释放CO2也会增加。3.栉孔扇贝的钙化和呼吸活动均随着酸化的加剧出现了明显下降。当pH降低到7.9时,栉孔扇贝的钙化率将会下降33%左右;当pH降到7.3左右时,栉孔扇贝的钙化率将趋近于0,栉孔扇贝无法产生贝壳,而此时栉孔扇贝碳呼吸率（RC）与耗氧率（RO）也分别下降了14%和11%。4.通过室内模拟实验发现贝藻养殖能够显著改变海水的CO2系统。大型藻类养殖能够有效吸收水体DIC,降低海水中P_CO2贝类养殖由于其呼吸和钙化活动的影响,也会使水体中DIC和上升,对海洋溶解度泵也有一定的干扰作用。而适当比例的贝藻混养可消除贝类钙化和呼吸释放CO₂的负面影响,在实现生态养殖的基础上最终加强了海洋碳汇的作用。5.通过室内实验、数学模拟的方法研究了桑沟湾养殖栉孔扇贝通过呼吸、钙化以及生物沉积等活动对湾内碳循环的影响。研究发现,养殖扇贝每年通过呼吸和钙化分别放出碳1.22×10⁴t和7.57×10²t;通过生物沉积作用每年有8.71×10⁴t碳被沉降到沉积物界面,通过贝壳钙化也可固碳1.06×10³t,这些碳绝大部分被埋藏从而脱离了地球化学循环。尽管养殖扇贝通过呼吸和钙化释放出部分碳,但有更多的碳通过生物沉积作用被埋藏,因此,从整体上看,养殖栉孔扇贝在湾内碳循环中起到了碳汇的作用。更多还原

【Abstract】 Ocean is the biggest active carbon sink on the earth, which adjust the global climate change effectively. Marine carbon cycle therefore is the most important link in the global carbon cycle. Marine carbon cycle is constituted by“Dissolve pump”、”Biology pump”and”Carbonate pump”, which are drived by mairne organisms life activities directly or indirectly. In coastal area, where have more rich primary production and more atctive organsims than off shore marine, so the biological impacts on carbon cycle more intensively in that area, especially in the shellfish and alga culture zones. Though we have known much on global marine carbon cycle now, there are many problems on the offshore carbon cycle. Studies of culture organisms’impacts on offshore carbon cycle can help us solving the problems above. So the impacts of salinity, temperature and marine acidification on calcification and respiration of Chlamys farreri, which is an important economic specie in northern of China are studied; and impacts of shellfish aqaculture, algea aquaculture and integrated multi-trophic aqaculture （shellfish-algea） on seawater’s system and“Dissolve pump”are simulated; Combining these research results and historical data evaluating ZhiKong scallops aqaculture’s role in jiaozhou bay carbon cycle. The main results as below:1. The calcification rate and respiratory rate of C. farreri are impacted by the salinity evidently. The calcification rate rises with salinity in the range of 15-25, then fails as salinity down. The respiratory rate increases with salinity in the range of 15-25, and decreases with salinity in the range of 25-35. And calcification rate, respiratory rate of CO2 and O2 all reach maximum in salinity 25, which are 0.33±0.02μmol.FWg^-1.h^-1, 2.32±0.10μmol.FWg^-1.h^-1 and 2.87±0.14μmol.FWg^-1.h^-1 respectively. CO2 relaxed by C. farreri also get max in that condition. 2. The calcification rate and respiratory rate of C. farreri are impacted by the temperature evidently, which are raise with temperature in the range of 5-25℃. Calcification rate, CO₂ respiratory rate and O2 respiratory rate raise from 0.19±0.01μmol.FWg^-1.h^-1、1.38±0.06μmol.FWg^-1.h^-1、1.64±0.11μmol.FWg^-1.h^-1 to 0.39±0.02μmol.FWg^-1.h^-1、5.44±0.29μmol.FWg^-1.h^-1、6.34±0.33μmol.FWg^-1.h^-1 respectively.3. Calcification and respiration of C. farreri decreased as pH declined significantly. Calcification rate decreased by 33% when the pH of water was 7.9. And at pH 7.3, calcification rate would be close to 0. CO₂ and O2 respiratory rates were reduced by 14% and 11% respectively at pH 7.3. 4. Seawater CO₂ system can be changed by the shellfish, algea aqaculture significantly. DIC can be absorbed by algea aqaculture, which result in the decreasing of P_CO2.DIC and P_CO2raising for the calcification and respiration of shellfish which can disturb the“dissolve pump”. Suitable proportion of shellifsh aqaculture and algea aqaculture may eliminate the negative effcets of releasing CO₂ from the respiration and calcification of shellfish. 5. Impacts on carbon cycle of C. farreri by respiration, calcification and biodeposition in Sanggou Bay was researched by the method of laboratory experiment and mathematical stimulating. These were 1.22×10⁴t and 7.57×10²t carbon releasing each year by respiration and calcification of C. farreri respectively; and these was 8.71×10⁴t carbon sinking to the bottom of sea by biodepositon, most of which would been buried and leaving geochemical circulation. Though carbon was releasing by respiration and calcification, more carbon was buried by biodepositon. So C. farreri should be considerd as carbon sink as a whole.更多还原