While the Wikipedia article on economic reproduction is kind of a mess, that seems to be the concept that this question is grasping at. I'll quote the following which is actually a very nice summary of Marx's answer.
Marx distinguishes between "simple reproduction" and "expanded (or enlarged) reproduction". In the former case, no economic growth occurs, while in the latter case, more is produced than is needed to maintain the economy at the given level, making economic growth possible. In the capitalist mode of production, the difference is that in the former case, the new surplus value created by wage-labour is spent by the employer on consumption (or hoarded), whereas in the latter case, part of it is reinvested in production.
So Marx's theory of simple reproduction explains that the circuit of capital must always stay in motion. Note here that the opposite of circulation is basically the "hoarding" of wealth. Capitalists don't hide their money under they mattress, because then they won't make a profit. They keep it circulation by reinvesting it in production (or at least putting it in a bank that can isssue loans). Hoarding (or non-productive investments, like in a real estate bubble) is a basic sign or symptom of an economic crisis. This is where Keynes draws from Marx, although his basic understanding fo the process is very different.
Marx's theory of expanded reproduction gets to the other part of the question, which is economic growth. And for Marx, decisively, this is not just a mere appearance of growth, but an accumulation of value-in-circulation. Picture an electrical circuit where the voltage tends to increase more and more over time. The source of the metaphorical "energy" in the capitalist economic system, for Marx, is human labor. It is the only commodity capable of adding additional new value to the circuit of commodities. The value of machinery and represents previous human labor accumulated in a productive physical form, and that is also part of what allows the scale of circulation to increase over time.
The other kind of circulation Marx touches on, but does not develop in very much detail, is metabolism, that is, the circulation of matter and energy in general, regardless of whether it is commodified. Humans in every society, like all living beings, take water, food, oxygen, sunlight, use it for our own biophysical reproduction, and then turn it into waste. In a health ecoystem, every form of "waste" is potnetially a necessary input for some other lifeform(s). This kind of circulation goes on regardless of whether or not nature is commodified. But the expanded reproduction of capial tends to disrupt circulation of matter and energy through ecosystems. It produces more waste (pollution, greenhouse gases, etc.) then the biosphere can manage to circulate. The circulation of commodities and the circulation of useful matter do not always fit well together. Ecological Marxists refer to this problem as the metabolic rift.