“The prevalence of anoxic environments rich in organic material, combined with the presence of nitrated compounds has led to an astonishing variety of underground organisms which live in the absence of oxygen and ‘breathe’ nitrate. Likewise, the scarcity of carbon in the environment has forced plants to economize on its use. Thus, all our efforts to return carbon to the biosphere will encourage the native life to proliferate. Conversely, the huge quantities of nitrate in the soil will be heaven to human farmers.”
— Lady Deirdre Skye, “The Early Years”
Ecological Engineering is a fourth-tier exploration technology that relies on Centauri Ecology and Gene Splicing. In the game, it lifts the mineral cap (meaning non-resource tiles can now yield greater than two minerals) and enables terraformer units to use the advanced terraforming options that were unlocked early by the Weather Paradigm. Since minerals are the most straightforward way for a player to build military units and base facilities, being able to suddenly accrue many more per turn is a massive improvement.
The quote that accompanies this massive industrial advance is a long discourse on Planet’s ecology. By now, the player’s seen a couple quotes that refer to the anomalously large quantities of organic nitrates in the biosphere. But here we see Lady Deirdre talking about how this has affected the vast, complex subterranean ecosystem on Planet. Whatever they have that fits the earthworm niche we’d recognize on Earth is certainly something pretty alien.
In context, this implies that understanding this subterranean ecology is necessary to shape the environment in any effective, lasting way. All the minerals are underground after all. So it seems to be necessary to figure out how to keep these crazy nitrate breathers out of the mineshafts and away from the machinery.
I believe this is also the first time that Deirdre speaks of the needs of the native ecology instead of focusing entirely on the needs of Earth plants and animals. Notably, in doing so, she mentions a potential route toward symbiosis. Since Earth plants have evolved to operate in a carbon-rich, nitrate-scarce environment and the native plants evolved to operate in a carbon-scarce, nitrate-rich environment, together they form a virtuous cycle. The Earth plants grow and flourish among all the easy-to-get nitrates. Then they die and their spare carbon causes an explosion of native plant life, which then provides the additional fertilizer for more Earth plants.
The idea that the two ecologies can be blended together harmoniously instead of necessarily competing is a core tenet of the Gaian religion. They believed that before they even made Planetfall. But only now, well into the tech tree, are they discovering the mechanism by which they might accomplish that.
Additionally, it’s worth noting that this quote also goes a long way toward explaining the curious lack of fossil fuels on Planet. Hydrocarbons necessarily include a lot of spare carbon. It’s in the name for a reason. So, if the entire biosphere is light on carbon for some reason, then it would make sense that there would be lots of little creatures roaming about on the search for the scarce material and growing fat on any reserves. Fast forward hundreds of millions of years and it makes perfect sense that all the oil would already be sucked out of the crust.