Scientists from Rice University and Texas A&M University-Corpus Christi’s Harte Research Institute for Gulf of Mexico Studies, have discovered that sea-level rise might have occurred in bursts rather than a prolonged gradual increase. Close to the last ice age glaciers melted at a rate so fast it created punctuated increases in the sea level that caused reefs to adapt in a very acute manner, but the current model for data quantification only allows scientists to take the numbers and apply a simple math equation. “[they] had to simply take the projected rise for a century, divide by 100 and say, ‘We expect sea level to rise this much per year,'” adds Rice marine geologist André Droxler, a study co-author. This approach lacked a true data set so Rice and his team set out to find quantifiable proof of these punctuated sea-level rise bursts.
“What these fossil reefs show is that the last time Earth warmed like it is today, sea level did not rise steadily, instead, sea-level rose quite fast, paused, and then shot up again in another burst and so on,” said Rice. “We have observed sea level rise steadily in contemporary time,” said coastal geologist and study co-author Jeff Nittrouer. “However, our findings show that sea-level rise could be considerably faster than anything yet observed, and because of this situation, coastal communities need to be prepared for potential inundation.” This study’s evidence was gathered on a 2012 exhibition onboard the Schmidt Ocean Institute’s research vessel Falkor. Using a multi beam echosounder (sonar) to map in 3D resolution, the team was able to observe growth patterns that have been empirically proven to be associated with sea-level rise. Visiting 10 fossilized reefs off the coast of Texas lying 30-50 miles offshore and in almost 200 feet of depth, the team noticed with even as much as 75 miles of distance between sites, the steps were all aligned at the same depth, meaning the same time in history. “In our case, each of these steps reveals how the reef adapted to a sudden, punctuated burst of sea-level rise, the terraces behind each step are the parts of the reef that grew and filled in during the pauses between bursts.” adds study lead author and graduate student Pankaj Khanna. “The coral reefs’ evolution and demise have been preserved,” Khanna said. “Their history is written in their morphology — the shapes and forms in which they grew. And the high-resolution 3-D imaging system on the R/V Falkor allowed us to observe those forms in extraordinary detail for the first time.” Read more here!