Science

The way to Benham Rise (First of two parts)

Sea-2

When I got a call from a former colleague last summer if I was interested to join her team in an expedition to the Benham Rise, I immediately and unwittingly said yes. At the time, I hadn’t the faintest clue what or where Benham Rise was. The only thing that filled my mind was that I was more than happy to be back in the water.

A week before the cruise, a quick Google search revealed that Benham Rise is a vast submarine plateau that rises from the seafloor some 250 kilometers east of Luzon. It has recently been recognized by the United Nations as a rightful territory of the Philippines. Although we cannot expect it to emerge as a gigantic island on which several malls might be built any time soon within our lifetime, the area is known as a rich fishing ground and is believed to potentially yield mineral deposits.

Little is known about this newly acquired territory, thus, the government was eager to send out expeditions to study it and assess its ecological and economic potential. As most parts of it lie three kilometers beyond the sea surface, there was one shallow point, the Benham Bank or Sea Mount, which immediately became obvious as the most logical starting point of the study.

For the Benham Bank expedition, a team of 28 researchers was assembled – physical oceanographers, chemical oceanographers, biological oceanographers, icthyoplankton (fish larvae) experts, fish experts, coral experts, benthos experts and marine microbiologists – coming from various institutions, namely, UP Diliman, UP Los Baños, UP Mindanao, UP Baguio, Xavier University, and Ateneo de Manila University. Despite the curious mix of specializations and affiliations, the team was not in any way a ragtag bunch.

Many members of the team knew each other well and have worked together in several other previous expeditions – to the Spratlys, the Sulu-Sulawesi Sea, and the Scarborough Shoal. Our ties with each other were anywhere from being former colleagues to former students, former mentors, former classmates, or former drinking buddies. The assembly of the team turned out to be a reunion of sorts –  touching base with each other, updating and confirming long forgotten rumors, reminiscing past experiences and mishaps, and reinforcing long held bonds of friendship and professional ties.

On May 3, we were herded into 2 vans and drove from UP Diliman to the Navotas fish port where we were to board the ship that would take us to Benham Rise. I kept hoping that we would at least be riding a decently comfortable ship and not a wooden, oversized outrigger boat. After all, we would be out at sea, with no sight of land, for at least two weeks.

As we entered the port, the omnipresent stench of rotting fish and the sight of rickety fishing boats did little to banish my apprehension. We finally reached our ship, the MV DA-BFAR, the research vessel of the Bureau of Fisheries and Aquatic Resources of the Department of Agriculture. The 14-year-old ship was a veteran, having been used in assessing the fishing productivity of various parts of the archipelago. The ship’s deck had bales of coiled rope, rows of concrete sinkers, and a stack of torpedo-shaped metal buoys. The ship was after all a research vessel for fisheries science.

However, things turned for the better as soon as I opened the hatch to enter the ship’s cabins – centralized airconditioning! The second mood turner turned up around lunchtime – the ship’s kitchen staff demonstrated that they can whip up good food.

We left port later that day and rounded the southern part of Luzon to reach the Pacific Ocean via Batangas and the Bicol peninsula. We traveled smoothly on the first day; however, as soon as we reached the seas that opened into the Pacific Ocean, things turned uncomfortably rough. We felt every pitch, roll and lurch of the ship in our head and in our guts as the ship steadily made its way to the open ocean. Quite a number of us started to skip meals in favor of the stable comfort of our beds.

Prior to the cruise, the diving team had been planning to make sure everything proceeded like clockwork. We all anticipated to be diving at maximum depths of sixty feet. This meant that we had about an hour at the bottom to do our work and stay well within the limits of safety diving.

Romeo M. Dizon, Ph.D. is an assistant professor of biology at the University of the Philippines Baguio. His research interests are coral ecology and coral restoration ecology.

We identified the most experienced divers among us who would dive to the site first; we assigned who would lay out the fifty-meter long transect line along which all the fish and coral surveys would be done; and we delegated various tasks such as video documentation, still photography, fish surveys, coral identification, and sediment sampling to the other members of the team.

Everybody knew what each had to do and the protocol seemed easy and hardly challenging. We’ve done this at this depth in the coastal zones countless times before. However, at the first site where we dropped anchor at Benham Rise, jaws dropped with incredulity. A deployment of a weighted video cam and a dive computer at the site confirmed what the ship’s instruments initially indicated – we were looking at a site that was three times deeper than what we had anticipated! One hundred eighty feet – and this was the shallowest point they found.

Plans A to H

We hurriedly huddled in the conference room, agreed to make a judgment call and came up with a diving plan B (replaced by plan C and all the way up to plan H in the next days as we had to carefully rethink our strategy prior to every dive). At this depth, we realized that the maximum time we could spend at the bottom was only 5 minutes and this additionally required up to half an hour of decompression time at several depths on the ascent to allow for the elimination for non-oxygen gases from the bloodstream. We took turns diving to the bottom to do very specific tasks and had the diving safety officers positioned at the 3 safety stops (60, 40 and 15 feet) to assist the others as they clung to the guide rope for their decompression stops. The diving plan was strictly enforced.

Anyone, not sparing the project leader, who deviated from the plan was “grounded” in the succeeding dives.

Diving to reach Benham’s bottom was a unique experience. One had to descend fast to maximize the air contained in the scuba tank, yet, one also had to equalize frequently to prevent the painful ear squeeze that is felt with every 5-meter descent. As one went deeper, the world gradually shifted into a monochromatic bluish gray as the longer wavelengths (such as red and orange) got absorbed in the upper layers of water. The pressure also increased with depth and rendered any movement to be a bit sluggish and the nitrogen that got dissolved in one’s bloodstream reached the brain, causing a mild narcosis.

The world at the sea bottom was surreal and dreamlike. One had to exert a conscious effort to stay focused on the task at hand – be it a fish survey, a sample collection or a videographic documentation – lest one completely forgot what he was supposed to do at that depth and came back to the surface having accomplished nothing.

Contrary to my expectations of deep-water habitats, the bottom was appreciably well illuminated because of the clear waters of the Pacific Ocean. The landscape at the bottom was a coral reef that was in very good condition, something rarely encountered now anywhere in the country. Every available space was occupied by tiers of plate-like corals, spreading to maximize their surface area in order to catch as much of the sunlight that was filtering down from the surface.

Sun-loving Halimeda seaweeds also grew in patches, shedding bits of calcified sand as each frond reached the end of its life. Fish also abounded in the area but stayed at a safe distance and kept a wary eye on the land-dwelling intruders. This was my first glimpse of, and intrusion into, a mesophotic or twilight reef, a deep-water ecosystem that receives just enough light to support sunlight-dependent organisms such as corals and seaweeds. This was a world that has remained practically untouched by man, at least until we came.

*An earlier version of this article appears in the June 2014 issue of Ti Similla, the faculty newsletter of UP Baguio. http://www.upb.edu.ph/

Romeo M. Dizon, Ph.D. is an assistant professor of biology at the University of the Philippines Baguio. His research interests are coral ecology and coral restoration ecology. Romeo M. Dizon, The Philippine Star

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