You have probably seen photos of icebergs melting in the ocean around Greenland or Antarctica, but did you know that you can hear them too? As the ice melts in the ocean it crackles. Small pockets of air expand as they are heated so bubbles of air in the ice give the bergy bits a distinct cracking noise as they warm up in the sun and melt in the ocean.

Glaciers naturally calve ice into the ocean, but with global warming glaciers are retreating and an increasing number are withdrawing from the ocean. In places once filled with ice like this, ice melt now enters the ocean as murky freshwater runoff. How will this affect the ocean? We’re here to find out.