|Europa: ice, cracks, and all|
And the question that I am most often asked about the Gw'oth is: living underwater, how did they ever develop technology? Doesn't it take fire to develop technology? As regards non-biological technology, my guess -- like many readers' suspicions -- is: yes.
One such reader question came up several weeks ago, far down in a thread of comments about a merely semi-related post. I answered with another comment in that same thread, but on reflection, I decided to address the topic in a post of its own. A post that people Googling "Gw'oth" will more readily find. This post.
There aren't major plot spoilers in my answer; I'm dealing primarily with back story before the opening of the series. Before humans and other species of Known Space ever met the Gw'oth. But if you continue, know you will encounter snippets of plot and text from a couple of the books.
Continue as you think best ...
*** Spoiler Alert ***
From Fleet of Worlds (the first book of the series):
They [the Gw'oth] could not have had ... any type of electronics, until after they went above the ice. Their only prior experience with gases would have been from undersea volcanic eruptions, or vacuum boiling of the water in a fresh ice fracture. Look at them now: We've got video of them wearing their pressure suits inside their above-ice buildings so that they can contain an atmosphere. Why? They need fire! Fire for what they still see as new industrial processes.Destroyer of Worlds (the third book of the series) gives a glimpse into the mind of a Gw'o named Er'o:
Fire was unnatural, chaotic, and transformative. Fire was fearsome. Early in the great breakout above the ice, fires had killed and hideously maimed many. As Er'o, he had never experienced a wildfire, but a mountaintop foundry consumed by flames was etched deep into Ol't'ro's memory. The Gw'otesht had lost two members to that terrible conflagration. Two dead! That accident had almost extinguished Ol't'ro themselves, long before Er'o's birth.
(If Gw'otesht and Ol't'ro are unfamiliar terms, I hope you'll excuse me for not clarifying. Explaining them would mean major spoilers. And you won't miss anything in the rest of this post by not knowing those terms.)
Less poetically: imagine an airtight (ice-sealed) igloo constructed above the ice by Gw'oth in leather suits. In Destroyer of Worlds we also read:
Early pressure suits had been only garments made from the tough hide of deep-sea creatures, trailing hoses to leather-bag "pumps" kneaded by helpers who remained beneath the ice.The igloo is filled with gases from, for example, chemical reactions or as produced by the local equivalent to cyanobacteria. (These local bacteria run off chemosynthesis, not photosynthesis.)
Once the Gw'oth have primitive electrotech -- and galvanic cells are pretty simple to make -- the Gw'oth could also electrolyze water to produce oxygen.
What do they burn in their oxygen? Perhaps hydrogen from electrolysis, although H2 molecules are tiny, and hence hard to capture -- or to keep captured. But carelessly permit H2 to accumulate from early electrolysis experiments, make a spark --
And it's Hindenburg time. The Gw'oth meet fire ... with a vengeance.
As for more manageable fuels, consider hydrogen sulfide captured bubbling up from undersea vents. Or flammable minerals (like sulfur) mined from the seabottom near dormant volcanoes. Or likewise flammable methane clathrates. On Earth, much of the deep ocean floor is covered in methane clathrates.
The Gw'oth are smart. They'll experiment.