Seeming 'Lack' of Marine Snow Explained: Feast and Famine on the Abyssal Plains (Video)
(Photo : 2012 MBARI)
Miles beneath the ocean surface are the cold and seemingly lifeless abyssal plains. These vast stretches of ocean floor play host to sea cucumbers, fish and an assortment of almost alien-looking sea creatures. The main food source for these animals is "marine snow," a slow drift of mucus, fecal pellets and body parts that sink down from the surface waters. Yet scientists have long been puzzled by the fact that this marine snow can't account for all of the food consumed by the denizens of these plains. Now, researchers have discovered how these animals survive in these cold ocean waters.
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In order to better understand what goes on in the depths of the ocean, the researchers studied animals living on the abyssal plain at a deep-sea research site about 13,100 feet below the surface. Including everything from sea cucumbers to sea urchins to grenadier fish, these animals seemed to thrive at these depths. The scientists decided they needed a closer look.
The researchers used several instruments to study the amount of marine snow arriving at the site, as well as its impacts on life in the deep. They suspended conical "sediment traps" above the seafloor to collect and measure the amount of marine snow falling through the water. They also used automated camera systems to take time-lapse photographs of the seafloor, which allowed them to track the behavior, numbers and sizes of larger deep-sea animals.
So what did they find? It turns out that large events may give animals a feast to survive during leaner periods. For example, the scientists found that from June to August, a large number of diatoms bloomed near the surface and sank rapidly to the seafloor, giving animals a wealth of relatively fresh food. They also found that from March to May, salps reproduced rapidly during surface waters and also sank. These blooms in particular contributed greatly to the amount of food available in the abyssal plains.
What is perhaps more interesting, though, is the fact that these deep-sea feasts may be increasing in frequency off the Central California coasts and at other sites around the world. Why? Some sites are receiving more nutrients from fertilizers and other sources of runoff that encourage these massive blooms. This could alter the types and number of creatures found on the abyssal plains.
The findings reveal a little bit more about the depths of the ocean. More specifically, they reveal how animals can survive during leaner times by feasting during times of plenty.
The research is published in the journal Proceedings of the National Academy of Sciences.
Want to see the abyssal plains for yourself? Check out the video below, courtesy of YouTube.