Occasional, but massive, explosions of sea-surface life provide a feast for creatures on the ocean floor, such as sea cucumbers and urchins. Normally, animals in the depths live a Spartan existence, getting by on crumbs from above. However, oceanographers recently discovered that after surface population booms die, they drift down to give deep sea life a smorgasbord equal to years of the normal food supply.
The daily routine of a sea cucumber, or any other ocean bottom animal, consists of scrounging around for morsels that constantly drift down into the abyss. This detritus is known as “marine snow,” but no human would want to catch these flakes on their tongue. The marine snow consists of decaying plants and animals, feces and other bits of nastiness.
The snow becomes a blizzard occasionally, according to 24 years of observations of the seafloor 4,000 meters deep and 220 kilometers (140 miles) west of the central California coast by Monterrey Bay Aquarium Research Institute oceanographers. The Proceedings of the National Academy of Science (PNAS) published their work.
For example in 2011 and 2012, a bloom of diatoms on the surface eventually died and sank. Diatoms are a type of phytoplankton, or microscopic algae that create their own food using sunlight like plants.
In addition to diatoms, other marine life can become a deep sea all-you-can-eat buffet. In May 2012, tremendous numbers of salps reproduced on the surface. Salps are soft-bodied animals that drift along ocean currents. Salps feed on phytoplankton, so blooms in marine algae fuel salp population booms. After death, the 2012 salp explosion sank quickly and blanketed the seafloor. So many of these tiny creatures fell that they clogged the devices used by the oceanographers to measure marine snow.
The left-overs from these occasional marine blizzard feasts settled into the sediment to feed bacteria and other organisms as the detritus decayed.
The authors of the PNAS study suggested that climate change may be increasing the frequency of surface life blooms off the U.S. Pacific coast and the subsequent marine blizzards. The diatoms and salps drag carbon into the depths with their bodies. This phenomenon could influence the global carbon cycle.
Top Image: Parastichopus californicus – Giant california sea cucumber (NOAA, Wikimedia Commons)