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1、Our team,My teammates: Zhou yuhong Lv jinmei Sun zhuanping Dong huan Shao haina Wang xia Tao lihong Mao yushan Wang rui Tian chunyan,The pros and cons of using protozoa as bioindicators of soil quality.,In a broad ecological sense, bioindicators are organisms that can be used for detection and quali
2、tative and/or quantitative characterization of a certain environmental factor or of a complex of environmental factors.,As compared to the meso- and macrofauna, protozoa (i) consume more food per mass unit, (ii) have a higher respiration rate per mass unit, (iii) have shorter generation and life tim
3、es,and (iv) reproduce faster .,A well-designed bioindication study should contain at least one group each of the micro-, meso- and macrofauna.,For instance, a comparative study on the effects of conventional and organic farming on soil animals revealed that testate amoebae were significantly reduced
4、 in the conventional plots, while earthworms remained unchanged.,testate amoebae,Furthermore,the indicator group(s) must be chosen according to the peculiarities of the habitat and the goal of the study.,1. Protozoa are an essential component of soil ecosystems. Changes in their dynamics and communi
5、ty structures very probably influence the rate and kind of soil formation and soil fertility.,The pros of using heterotrophic soil protozoa as bioindicators ：,2. Protozoa can react more quickly to environmental changes than any other eukaryotic organism and can thus serve as an early warning system
6、and excellent tool in bioassays .,3. The eukaryotic genome of the protozoa is similar to that of the metazoa. Their reactions to environmental changes can be more convincing than those of prokaryotes.,4. Morphologic, ecologic, and genetic differentiation among globally distributed protozoan species
7、is low.,5. Protozoa are particularly abundant in those soil ecosystems that almost or entirely lack higher organisms due to extreme environmental conditions.,6. Protozoa are not readily dislodged in soil. Many are ubiquitous and are useful for comparing results from different regions.,The cons of us
8、ing protozoa as bioindicators: 1. There is an immense number of species, many of which have not yet been described; more than 1000 may occur in a square metre of forest soil.,2. Enumeration of soil organisms is difficult and time consuming . 3. Animals need other organisms for food. Thus, the indication often remains unspecific.,4. Most soil organisms are inconspicuous and invisible to the naked eye, making them unattractive to many potential investigators. 5. There is a lack of comprehensive, easy-to-use identification literature.,THANKS!,
