Below 2,000 metres, almost nothing moves quickly. What looks empty on a sonar readout is a careful exchange between organisms that trade carbon, nitrogen, and light. For a long time we only measured it by what washed up.

Below 2,000 metres, almost nothing moves quickly. What looks empty on a sonar readout is a careful exchange between organisms that trade carbon, nitrogen, and light. For a long time we only measured it by what washed up.

Below 2,000 metres, almost nothing moves quickly. What looks empty on a sonar readout is a careful exchange between organisms that trade carbon, nitrogen, and light. For a long time we only measured it by what washed up.

Below 2,000 metres, almost nothing moves quickly. What looks empty on a sonar readout is a careful exchange between organisms that trade carbon, nitrogen, and light. For a long time we only measured it by what washed up.

Below 2,000 metres, almost nothing moves quickly. What looks empty on a sonar readout is a careful exchange between organisms that trade carbon, nitrogen, and light. For a long time we only measured it by what washed up.