A Birds-eye View of Island’s Underwater Beauty

Source: The Royal Gazette

In the past, if you wanted to measure Bermuda’s reefs you had to don a scuba tank and dive, tape measure in hand; but now, a new scientist at Bermuda Institute of Ocean Sciences, Dr Eric Hochberg, hopes to get a little help from above.

Dr Hochberg, a coral reef expert, plans to use satellite imagery to help Bermuda gain a better understanding of it’s coral reef system. He recently became the principal investigator for the Marine Environmental Program (MEP) at BIOS. He previously worked as assistant professor at Nova Southeastern University’s Oceanographic Center and National Coral Reef Institute in Florida.

At BIOS, he now heads up crucial research and monitoring associated with tasks such as identifying potential new sources of pollution, identifying effects associated with regional and global changes such as coral bleaching events or disease outbreaks, and drawing the line between effects of climate and non-climate stresses.

Ecological surveys are conducted at more than 20 locations across the Bermuda platform. A new MEP that kicks off this year is the detailed mapping of Bermuda’s shallow reef habitats, including benthic communities (crabs, clams and other creatures that live in the sediment on the ocean floor) and bathymetry (the study of underwater depth) to 20 metres depth.

Whereas previous reef mapping efforts have provided information on select sites across the Bermuda platform, the objective of this programme, based on high definition satellite images, is to establish a baseline for the entire Bermuda reef ecosystem.

“We want to understand what is happening to reefs, and how they are responding to the impact of nature and humans,” said Dr Hochberg. “We want to know how the coral reef system works. We also want to understand the impact of ocean acidification and global warming on the coral reef.”

He said the whole reef platform in Bermuda has been mapped by Thad Murdoch, head of the Bermuda Reef Ecosystem Assessment and Mapping Programme with the Bermuda Zoological Society.

“Mr Murdoch took aerial photos and put them on a computer and with a computer mouse drew boundaries around areas,” said Dr Hochberg. “He said ‘this area of the reef is the hard bottom’. It has all been mapped that way. I am not trying to supplant what Thad has done, I am trying to augment it. I am not trying to step on anyone’s toes.”

He said the traditional way of reef mapping, using first-hand observation, worked well, but was limited in the area that could be covered. In fact, globally, only 0.5 percent of the reef system has been mapped. He hoped that satellite data would fill in some gaps.

Earlier this year Dr Hochberg was named to the board of editors for the journal ‘Remote Sensing of Environment’. He is also co-lead on a project to survey the reefs around Guantánamo Bay, Cuba.

“We visit places in the water and get high quality data with our own eyes and with cameras,” he said. “We always have photo documentation of everything. The satellite fills in the rest. It lets us see the spaces in between, and allows us to measure how much space there is.”

Dr Hochberg uses a specially programmed computer to identify the depth and density of coral captured in satellite imagery, to provide more accurate data.

He actually dived in Bermuda’s waters for the first time last week and had a look at Bermuda’s corals. He admitted that the water was chillier than he expected, but he was both impressed and slightly puzzled by what he found.

“Bermuda doesn’t get a lot of light on the reef in the winter, compared to other reef systems in the world,” he said. “We are pretty much as far north as reefs will grow. The species of coral that is here tend to grow slowly anyway, compared to other species in the lower Caribbean. Despite that it is in incredibly good condition compared to other reefs I have seen in the Caribbean.

“If you took a patch of Bermuda’s reef and put it in the Florida Keys, they would be ecstatic at the amount of coral there is. Bermuda has a lot of fish too, just from my personal observation, although there isn’t a lot of diversity of species compared to other places.”

He believed that satellite data might help scientists to answer the mystery of why Bermuda’s corals flourish despite the strikes against it in terms of light and cool waters in the winter.

“They are quite beautiful reefs,” he said. “I am surprised there isn’t more eco tourism here”.

Dr Hochberg has authored numerous peer-reviewed publications relating to the field, including the sole chapter on the topic in the important book ‘Coral Reefs: An Ecosystem in Transition’. He served as chair of NASA’s HyspIRI Sunlight Subgroup, and he has advised NASA on coral reef remote sensing. He has completed more than forty reef mapping projects in Hawaii, the wider Pacific, and the Caribbean.