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Dive Dry with Dr. Bill

#505: Sea Snot

Few things can destroy a diver's image topside more quickly than the appearance of a big gob of snot emanating from their nose once they return from a dive. The most beautiful mermaid, looking fantastic in her wetsuit (and that's hard to do), cancels all that out when a goober is prominently displayed from a nostril. Even a stud muffin like yours truly can turn a woman's heart off if I don't check myself in the mirror first. Come to think of it, even when I do they seem to run... away!

We've had a good long spell of warm water this fall. It's been several years since I've seen conditions quite like this. However, being in hot water is not always a good thing. A few weeks of temperatures above about 68 F and our beautiful giant kelp forests fall apart. It isn't so much the elevated temperature as the fact that water above that temperature contains very few nutrients to sustain the incredible growth of giant kelp. It also affects the production of plant plankton (phytoplankton) in coastal waters and out in the open sea. And this creates a rather snotty situation underwater as well.

Sea snot is a term applied to gobs of goober-like mucilage that may appear in substantial quantity during such periods. Over the three weeks the Japan Underwater Films crew was out here shooting giant sea bass with me, conditions went from a spectacular 100-120 ft of visibility to about half that which is still pretty darned good. However, the waters during our last week of filming were "saturated" with sea snot, rendering much of the footage we shot less than ideal. You think I'm talking about tiny goobers the size of the ones in a diver's nose (or that of a young child). No, I'm talking about ones that are gargantuan... sometimes approaching two feet in length!

When I first saw the sea snot close to shore, I assumed the mucilaginous mess was originating from the deterioration of our giant kelp. However, as we raced out into the open ocean aboard the King Neptune to film dolphins, the sea snot was present miles out at sea. Even our island's rich kelp forests were not extensive enough to be responsible for the magnitude of this invasion. I knew sea snot was a form of mucilage created out of organic matter exuded by marine life including plant plankton. It often serves as a substrate for the dead bodies (and even living ones) of other living things like zooplankton, not to mention bacteria and viruses, to accumulate upon.

When a photosynthetic seaweed or plant plankton becomes nutrient stressed during warm water periods, it releases more and more carbon into the water. This organic matter is what creates the sea snot. We have a pretty good example of the oceanographic conditions that trigger this right now in late September. It can also be triggered when nutrients are used up by a phytoplankton bloom or other mechanism, and the water contains far more carbon than the necessary nutrients for algal growth like nitrogen and phosphorus.

Scientists discovered that the outpouring of carbon during the Gulf of Mexico oil spill also created a similar situation, but that mucous or mucilage also trapped toxic substances. Sea snot is part of the marine "snow" that falls from the upper layers of the ocean to the depths, providing nutrients to critters living in the dark regions below. Sea snot normally is fairly small, perhaps a few millimeters in length, but when it is very sticky it can collect more mass and become greatly enlarged as we see now off the island. This very large sea snot sinks at a more rapid rate than the usual, smaller stuff and thus can collect organic matter from shallower waters and quickly send it down to the depths.

Apparently sea snot is more common in the Mediterranean Sea than in our waters, probably because here the ocean is bathed by the cool California Current coming from the north. It is said that the slime balls there can reach lengths of 125 miles! I guess the summer I spent free diving Italy and Greece before coming to Catalina was a cool one as I can't remember seeing any of it there. When I arrived here in 1969, I planned to spend a year teaching at Toyon, and save enough money to return to Greece. After 43 years I almost have enough saved and now I have an additional reason to dive there!

© 2012 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

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Gobs of sea snot in Catalina waters during late September, 2012.

This document maintained by Dr. Bill Bushing.
Material and images © 2012 Star Thrower Educational Multimedia