Migrating to the Light: All Creatures Great and Small

Hmmm, do we have more in common with deep ocean dwellers than we realize?

As an ardent birdwatcher, I derive great joy and much inspiration from the wonder of the spring and fall migration of birds. I never imagined that there might be an aquatic equivalent. But it turns out to be true, although this migration requires a bit more sophisticated equipment than a pair of binoculars.

Vertical Migration is a pattern of movement by small ocean organisms – notably crustaceans, which are generally less than an inch long – over a 24 hour period. Understanding this phenomenon requires a bit of knowledge of oceanography – specifically, the different levels or zones in the earth’s oceans each of which are progressively darker and colder.

Sunlight or Illuminated Zone. In this shallowest zone, there is enough sunlight for photosynthesis to occur. Photosynthesis (in case you cannot remember your high school biology) is the process used by plants and organisms to convert light energy to chemical energy. There is a high concentration of plants and animals in this zone.

Twilight or Middle Zone. This second layer has some sunlight but not enough for photosynthesis to occur. Consequently, fewer organisms live in this zone.

Midnight or Deep Zone. This layer is pitch black all the time and is home to a select group of deep ocean dwellers. Some of the species that call this zone home are bioluminescent which means that they emanate light. Fireflies of the deep, if you will.

Lower Midnight Zone. This lowest layer, once believed to be bottomless, is again pitch black as well as extremely cold with very high pressure. Only a few very hardy organisms are capable of living in this very inhospitable environment.

Now back to the original concept. Ocean species living in the lower three zones migrate upwards during the night to feed on zooplankton and other organisms that live in the Sunlight Zone. This vertical migration attracts small fish and ocean creatures who feed on these dwellers of the deep. Larger, predator species, such as sharks, in turn move in to feed on the fish.

In the early morning hours, the process reverses. Deep ocean creatures return to their home zone and the predator species disperse. An entire ebb and flow of migration every 24 hours.

Vertical Migration is one of many mysteries of the world’s oceans. Science is still only scraping the surface of these deep (literally and figuratively) secrets. Current analysis indicates that between 700,000 and one million species live in the world’s oceans with between one-third and two-thirds of these species yet to be named and described.

The daily Vertical Migration, upwards to the light and back to the depths, of deep sea ocean creatures can be seen as a metaphor for our own yearning toward the light. We strive each day for a little more understanding and more nourishment for our minds, hearts and souls.

Migrating to the light is a never-ending quest, for all creatures great and small, in which the process is as important as the destination.

~ Michael Robert Dyet is the author of “Until the Deep Water Stills – An Internet-enhanced Novel” – double winner in the Reader Views Literary Awards 2009. Visit Michael’s website at www.mdyetmetaphor.com or the novel online companion at www.mdyetmetaphor.com/blog .

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