能量和養(yǎng)分通過生態(tài)系統(tǒng)的流動由代謝限制和養(yǎng)分供應(yīng)兩個因素決定。現(xiàn)在,，對由微生物釋放到環(huán)境中去消化有機質(zhì)的外部“生態(tài)酶”（ecoenzymes）所做的一項研究表明,，這些酶的活性遵從一個一致的比例關(guān)系,，這種關(guān)系獨立于微生物群落的組成。
研究人員在土壤和淡水沉積物中對調(diào)控異養(yǎng)微生物群落大部分碳,、氮和磷攝取的四種酶進行了測量,，在所有這些生境中，碳,、氮和磷的吸收活性比都接近1:1:1,。生態(tài)酶活性可被看作是將兩個主要生態(tài)理論（化學當量理論和代謝理論）統(tǒng)一起來的一種聯(lián)系，因為酶的表達是由環(huán)境養(yǎng)分供應(yīng)狀態(tài)的隨機性專門調(diào)控的細胞代謝的一個產(chǎn)物,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 462, 795-798 (10 December 2009) | doi:10.1038/nature08632
Ecoenzymatic stoichiometry of microbial organic nutrient acquisition in soil and sediment
Robert L. Sinsabaugh1, Brian H. Hill2 & Jennifer J. Follstad Shah3
1 Biology Department, University of New Mexico, Albuquerque, New Mexico 871312, USA
2 US Environmental Protection Agency, National Health & Environmental Effects Laboratory, Duluth, Minnesota 55804-2595, USA
3 Biology Department, Duke University, Durham, North Carolina 27708, USA
4 Correspondence to: Robert L. Sinsabaugh1 Correspondence and requests for materials should be addressed to R.L.S.
Biota can be described in terms of elemental composition, expressed as an atomic ratio of carbon:nitrogen:phosphorus (refs 1–3). The elemental stoichiometry of microoorganisms is fundamental for understanding the production dynamics and biogeochemical cycles of ecosystems because microbial biomass is the trophic base of detrital food webs4, 5, 6. Here we show that heterotrophic microbial communities of diverse composition from terrestrial soils and freshwater sediments share a common functional stoichiometry in relation to organic nutrient acquisition. The activities of four enzymes that catalyse the hydrolysis of assimilable products from the principal environmental sources of C, N and P show similar scaling relationships over several orders of magnitude, with a mean ratio for C:N:P activities near 1:1:1 in all habitats. We suggest that these ecoenzymatic ratios reflect the equilibria between the elemental composition of microbial biomass and detrital organic matter and the efficiencies of microbial nutrient assimilation and growth. Because ecoenzymatic activities intersect the stoichiometric and metabolic theories of ecology7, 8, 9, they provide a functional measure of the threshold at which control of community metabolism shifts from nutrient to energy flow.
