A Better Understanding of Coral Reef Ecosystems

Pelagic predators such as these barracuda, Sphyraena qenie, are part of the coral reef ecosystem in the U.S. Line Islands (NOAA Photo by Kevin Lino).
A team of scientists have embarked from Hawai'i on a three-month survey of coral reef ecosystems at Johnston Atoll, the U.S. Phoenix Islands, the islands of American Samoa, and the U.S. Line Islands in the tropical Pacific Ocean. The overarching objective is to better understand the coral reef ecosystems of these areas, many of which are seldom explored. The research expedition is part of a regular monitoring program, conducted by the Coral Reef Ecosystem Division (CRED), headquartered in Honolulu, Hawai'i. The expedition is supported by NOAA's Coral Reef Conservation Program and involves extensive cooperation among NOAA scientists and research partners, including the University of Hawaii Joint Institute for Marine and Atmospheric Research (JIMAR), the U.S. Fish and Wildlife Service, San Diego State University, and the Papahānaumaokuākea Marine National Monument.

The research expedition will be carried out from February 27 to May 24, 2012 aboard the NOAA ship Hi'ialakai. Under the leadership of Chief Scientists Dr. Jill Zamzow, Dr. Bernardo Vargas-Angél, and Jamison Gove, a diverse team of researchers will be conducting multidisciplinary coral reef ecosystem surveys, assessing the status of fishes, corals, algae, marine invertebrates, and the oceanographic conditions in which these organisms exist. The scientific data collected during the three-month research expedition will enable informed and effective implementation of ecosystem-based management and conservation strategies for coral reef ecosystems, helping to ensure their protection for generations to come.

Friday, March 20, 2009

Potable water at sea.

"Water, water, every where,
Nor any drop to drink."
- The Rime of the Ancient Mariner
- S. T. Coleridge

Out in the middle of the Pacific Ocean we might have to worry about a situation like this, but not on the NOAA ship Hi'ialakai, where a team of engineers, who amongst other tasks, convert the sea's salt water to fresh, potable H2O.

Chief Engineer Kevin Sorbello explained in detail how the potable water is distilled from the sea's salt water, while 1AE Jesse Duncan was kind enough to give a tour of the engine room, motor room , AC and refrigeration room, and various other systems on the ship. It is very interesting and not everyday you get a chance to see these parts of a vessel.

The ship is equipped with four Caterpillar D398 diesel engines that produce 230 KW at 600 volts, 3 phase, 60 Hz power during transit. Some of this energy goes through a transformer where it is converted to 450 volts and sent to the switchboard for running everyone's personal electrical items and all the ship's electrical equipment other than the main propulsion motors.

The rest of the 600 volt energy produced by the diesel engines is converted from AC to DC and used to power the ship's two 900 Horsepower DC motors which are attached to the ship's propellers. These motors can reach up to 180 RPM, which translates into a speed of about 12.5 knots.

Potable water is produced in an evaporator, or "distillilation unit", where a venturi system powered by water creates a low pressure area inside of the "distiller" by ejecting air out of the evaporator, thereby lowering the temperature the incoming water has to reach before boiling. Water pumped through the diesel engine's cooling system, at about 180 to 190 degrees F, is diverted through a heating section of the evaporator where it heats the incoming salt water under a vacuum so that it boils off the fresh water, leaving the salt behind. The extra salty water stays at the bottom and gets pumped back into the ocean with a brine pump. Sea water coming into the distiller passes through a "preheating" section at the top of the distiller where it cools the vapor boiled off in the lower section so it that it condenses the fresh water ,and at the same time, preheats the salt water before it's reintroduced into the lower section to be boiled. The condensed freshwater is collected and pumped through a bromination unit on its way to the ship's potable water tanks, which together hold 5090 gals of water. The distillers can each produce as much as 2000 gals per day at maximum capacity, for a total of 4000 gals a day under optimum conditions. This water is about as pure as you'll find anywhere, with only about 2 PPM chlorides! This water is very safe for us to bathe with, cook and drink!

Water, water everywhere, and thanks to the engineers, plenty for us to drink!

1 comment:

  1. WOW! That is awesome! The Hi"ialakai is on the cutting edge! I'm sure the crew loves the fact that they don't have to take salt water showers!