Coral May Be Moving North

Abstract

While the ranges of many terrestrial animals, such as butterflies and birds, have recently expanded in response to global warming trends, there have been few examples of such changes for marine species. the recent discovery of the staghorn coral (Acropora cervicornis) near Fort Lauderdale, FL and elkhorn coral (A palmata) on the Flower Garden Banks in the northern Gulf of Mexico provides evidence of the first known range expansion of a Caribbean coral in response to global warming. appearance of these corals north of their previously known range is associated with decadal-scale increases in sea surface temperature, says marine geologist William Precht, a consultant with PBS&J (Miami, FL), who presented the research results at the Geological Society of America meeting in Seattle, WA (November 2003). The geologic record supports the theory that these expansions are caused by warming ocean temperatures. In Florida, fossil reefs dominated by Acropora underlie these new colonies, adds Precht. Those ancient reefs died more than 6000 years ago, towards the end of the period known as the 'mid-Holocene Warm', when the water was 1-3 °C warmer than at present. From then until now, there has been no new growth. We have young corals flourishing out here where they basically have no business being, comments James Thomas, a scientist at NOVA Southeastern University, Dania Beach, FL, and a contributor to this work. However, we are finding lots of tropical species where they would not be expected to occur. It is possible these new outcrops represent periodic recruitment events that have gone unnoticed, rather than an Acroporid corals on the move.