Measuring the exact metabolism of deep-sea corals for the first time

about the episode

They are also called underwater tropical rainforests, cold water corals and deep sea sponges. And this is not surprising, because the ecosystems they form are full of life and biodiversity. They also play an important role in the ocean’s carbon cycle.

But things are not going well for these deep-sea hotspots. They are under pressure from fisheries and ocean acidification, among other things. A reason for many researchers to study these reefs in depth. Evert de Froe of the Royal Netherlands Institute for Marine Research is one of them.

One of the main questions he and others are trying to answer is: How could there be so much life in one of the darkest, coldest places in the ocean? It took two trips on a research ship to the northwest region of Ireland to find out.

In cold-water corals, they studied exactly how seawater flows and something caught the eye. In this region, water masses of different densities flow one over the other. This creates underwater waves that can sometimes reach 200 to 300 meters in height. If they come into contact with a coral mountain on the sea floor, the strong drag can cause food particles to even reach coral reefs as deep as 700 meters.

They also took a quarter of a square meter of coral and aquatic life all in a sealed sealed box. By measuring the presence of inorganic nitrogen such as nitrate and ammonium, they were able to determine the corals’ metabolism. Among other things, they saw that coral reefs convert on average five times as much carbon as an area with only sand. This requires a lot of food.

Could these measurements also be used to predict where other reefs are hiding in the deep sea, so we can better protect them? With a simulated model of moving food over a deep-sea coral reef, De Froe thinks he’s now off to an important start.

Read more about research here: Strong currents carry food to the deep sea coral reefs (Dutch text below).