The conversation then shifted to the importance of jellyfish. I explained that these primitive animals occupy an important place in the ocean ecosystem. I explained how they eat large quantities of fish, invertebrates and plankton, recycling nutrients and otherwise occupying an important niche in the marine food web.

True jellyfish are members of the Cnidarians. These and several related phyla, the members of which, like the Portuguese Man-o-War and the familiar sea walnut that phosphoresces in boat wakes on the bay, are all often commonly called jellyfish. Their evolution is relatively obscure, since they are mostly water with no hard body parts to leave a good fossil record. But their primitive nature is inferred from their simplicity and their similarity to sea anemones, corals and other ancient lineages. They are little more that a pulsating bell, a digestive tract, and reproductive organs. Strangely, however, one group of the jellyfish-like creatures, the tropical, and often deadly, box jellies, possesses fully functional eyes. Clearly there is much about these beautiful creatures that we have yet to unravel.

One more aspect of the important role that jellyfish play in marine ecosystems has recently been discovered. In a recent issue of the journal Nature, researchers describe how jellyfish mix and stir the ocean waters through which they swim, distributing plankton, nutrients, and thermal energy to an amazing degree. In fact, these researchers hypothesize that jellyfish may be as important a force in ocean mixing as are winds and tides.

Not to belittle this role, but jellyfish do much more than provide food for Ocean Sunfish and sea turtles.

Global Warming Update

In spite of this year’s very cool temperatures, the evidence of global warming continues to pour in. In a collaboration between NASA and U. S. Navy scientists, a new analysis has been conducted that considers greenhouse gas emissions, volcanic activity, the Pacific Ocean phenomenon known as El Nino, and solar radiation. El Nino is part of an ocean current shift that greatly impacts Pacific fisheries while driving oscillations in global temperatures and precipitation patterns. Volcanic activity actually cools the earth’s climate by spewing cloud forming sulfurous gasses high into the atmosphere. Solar radiation, however, is the most important and least understood determinant of the global temperature. In a future Conservation Issues, we will discuss the role of the sun’s variability in our climate changes.

The new analysis suggests that global temperatures over the next five years could significantly exceed previous predictions. One interpretation of this model suggests that, barring a major volcanic eruption, after next year half of all years in the near future will be warmer that the warmest year of all time, which was 1998.