Science may be going to the natural frontiers on Earth but what about the indoor biome?

If you add up the area of the indoor biome in Manhattan — including its walk-ups and high-rise apartments — it’s three times bigger than the area of the island of Manhattan itself…

And yet the indoor biome remains at science’s frontier. “We know virtually nothing about it,” said Laura J. Martin, an ecologist at Cornell University.

In the journal Trends in Ecology and Evolution, Ms. Martin and 24 fellow scientists have issued a manifesto urging serious scientific investigation of the indoor biome. We need to find out not only what is living in our homes and workplaces, the scientists say, but how they got there…

Dr. Dunn and his colleagues argue that, ecologically speaking, our houses have a lot in common with caves. In both habitats, temperature and humidity are much steadier than outside, making for stable environments. But both lack the dense vegetation that most other biomes have, so there’s less food to be had…

But our houses also have otherworldly ecological niches, like shower heads and freezers, that can support more biological diversity than you’d find in a cave.

This may be a bigger issue than ever for three reasons:

1. People have become more sedentary than in the past for a variety of reasons, which often means they are inside more.

2. The indoors has made it possible to adapt to more inhospitable habitats. (Think heating and air conditioning.) Yet, this also provides more potential for mixing organisms.

3. And the reason that might funnel the necessary money to study the great indoors: health. When is the indoor biome healthy for humans and when is it not? We know about some features of this – think exhaust and particulates in garages or from fireplaces or bacteria in the kitchen or bathroom – but do we know the whole complex story? What if the indoors was making us less healthy?