Dive Dry with Dr. Bill

#210: Bacteria

A few years ago, I was diving at the Jean-Michel Cousteau Fiji Islands Resort in Savusavu as a guest of Jean-Michel and Dick Murphy. Fiji is one of the soft coral capitols of the world and a first class place to dive. The diving there was fantastic, although the native kava ceremony each night left my mouth tasting of muddy waters (and I don't mean the blues artist). One of my most vivid memories had nothing to do with the marine life, or the kava.

I chose to leave my regular dive fins behind and suited up with a pair of closed heel fins from the resort. They were sized a bit too small, and ended up leaving large cuts on both my ankles. It wasn't long before these cuts became infected. Tropical waters have high species diversity, and that includes bacteria! The warm waters allow them to thrive once they get a "foothold" (pun intended). Fortunately I usually carry the antibiotic Cipro when I travel overseas, and that wiped out the bacteria but not before they left some small scars.

Now we all are aware of the bacteria that live in our terrestrial environments. We are often reminded of their presence when we get sick. Bacteria are also important in maintaining the ecological cycles that maintain the flow or "recycling" of nutrients through a system. Did you know that bacteria also play an important role in the marine environment and its food webs? Those of us in Avalon, and elsewhere in southern California, are certainly aware that their presence in our bay can cause beach closures. And our sewage treatment plant requires special bacteria to breakdown the product delivered to it because of our salt water toilet system on the island.

A paper by USDA biologist Ronald Fayer estimates that the world's human population and its livestock generate about 4 billion metric tons of feces each year. Much of this is transported through runoff from agricultural and developed land surfaces, as well as actual wastewater discharge, into our rivers and eventually to our coastal waters. Here pathogens enter marine food webs, often by being filtered out by shellfish, suspension and filter feeders, or bottom feeders. Toxoplasmosis, a disease caused by parasites associated with these bacteria, is suspected in the increased death rate among California's sea otters which feed largely on shellfish.

As human and animal populations grow, and more of them are concentrated in coastal regions, this problem will only increase. Another important factor is the development of concentrated farming to raise pigs, chickens and cattle at high densities. In America, most of our wastewater stream goes to treatment plants where it is treated at the secondary or even tertiary level and therefore is relatively clean. It is the "non-point" runoff from the land, and overflow from storm drains, that comprises much of the problem. Fortunately this is not a major issue, and the removal of goats and pigs as well as reductions in bison numbers can only have helped reduce this problem here on Catalina, at least in waters near the undeveloped areas.

Of course not all bacteria in the ocean originate from human activity on land. Bacteria of many different types are also important parts of the natural food webs of the undersea world. Some come from the "poop" of marine animals including invertebrates, fish and marine mammals. Have you ever seen whale poop? Wow! Other bacteria are involved in the digestion of food by marine life. The carcasses of dead marine life from plankton to giant whales also require bacteria to help decompose them and turn their bodies back into nutrients to sustain the food webs. As I wrote in an earlier column, squid use bacteria to produce antibiotics that keep other bacteria from infecting and spoiling their eggs while they develop.

The extremely warm waters, especially during July, seem to have contributed to the bacterial populations in our waters. While diving the warmest sites like those from the East End to Long Point, I have observed what appear to be bacterial infestations on dead sheep crabs, sponges and other marine life. No such infestations have been seen in cold water sites such as Ship Rock or deeper depths. Many of our colder water sea urchins, like purples and reds, were killed off by Vibrio bacteria.

By the way, were you aware that bacteria actually have an interesting sex life? Bet you thought I'd never mention that in an article about these simple organisms. When I taught an animal behavior class at the old Toyon School, one of my lessons was on "the sex life of the bacteria." I'll just mention it in passing here. Just goes to show that "munching" (on us in this case) and "mating" are still the fundamental functions of all species, including at this tiny scale! Why, it's just in our genes from the simplest (men) to the most complex of animals (women!).

© 2006 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles" or "Gentle Giants: Giant Sea Bass" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!

Spherical (cocciform), rod shaped (bacilliform) and spiral-shaped bacteria
plus the "dreaded" Escherichia coli bacteria.

This document maintained by Dr. Bill Bushing.
Material and images © 2006 Star Thrower Educational Multimedia