Barlow C, Volk T
ARTA, Inc., Seattle, WA 98154.
Biosystems. 1990;23(4):371-84. doi: 10.1016/0303-2647(90)90018-v.
While energetically open, the biosphere is appreciably closed from the standpoint of matter exchange. Matter cycling and recycling is hence a necessary and emergent property of the global-scale system known as Gaia. But how can an aggregate of open-system life forms have evolved and persisted for billions of years within a planetary system that is largely closed to matter influx and outflow? The puzzling nature of a closed yet persistent biosphere draws our attention to the course of evolution of fundamental metabolic strategies and matter-capture techniques. It suggests a facet of the Gaia hypothesis, framed in terms of persistence. The oceans, atmosphere, soils and biota constitute a complex system which maintains and adjusts matter cycling and recycling within the constraints of planetary closure such that open-system forms of life can persist. This weaker version of the Gaia hypothesis may be useful because it readily lends itself to at least one form of test. What is the solution to the closed biosphere puzzle, and does it indicate that Gaia merits status as a discrete entity? We suggest several disciplines within the field of biology that might provide tools and perspectives toward reaching a solution. These disciplines include artificial closed ecosystems, prokaryote evolution, the nexus of thermodynamics and evolutionary biology, and hierarchy theory in ecosystem modeling and evolution theory.
虽然从能量角度看生物圈是开放的，但从物质交换的角度来看，它却是相当封闭的。因此，物质的循环和再循环是被称为盖亚的全球尺度系统的一种必要且新兴的属性。但是，在一个对物质流入和流出基本封闭的行星系统中，开放系统的生命形式的集合是如何进化并持续数十亿年的呢？封闭却持久的生物圈的这种令人费解的性质，将我们的注意力引向了基本代谢策略和物质捕获技术的进化历程。它暗示了盖亚假说的一个方面，即以持久性为框架。海洋、大气、土壤和生物群构成了一个复杂的系统，该系统在行星封闭的限制范围内维持并调整物质的循环和再循环，以使开放系统形式的生命能够持续存在。盖亚假说的这个较弱版本可能是有用的，因为它很容易至少接受一种形式的检验。封闭生物圈谜题的解决方案是什么，它是否表明盖亚有资格成为一个离散的实体呢？我们提出生物学领域内的几个学科，它们可能为找到解决方案提供工具和视角。这些学科包括人工封闭生态系统、原核生物进化、热力学与进化生物学的联系，以及生态系统建模中的层级理论和进化理论。
