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Ocean Research


March 2013 Issue

AUV, ROV Uncover Hidden Underwater Faults
Monterey Bay Aquarium Research Institute (MBARI) and U.S. Geological Survey geologists have brought underwater faults offshore California, hidden by ocean waves and masked by sand and mud on the seafloor, into view for the first time.

These faults are notoriously difficult to see and even more difficult to study. As a result, geologists struggle to evaluate the risks associated with these faults and often cannot include them in seismic hazard assessments. The team's methods were very similar to those used to study faults on land, but this was among the first studies to take similar measurements underwater, said MBARI geologist Charlie Paull.

The team conducted its studies off the coast of Southern California in the California Borderland. The researchers collected ultrahigh-resolution images of the seafloor using one of MBARI's AUVs, which also measured the thickness of the muddy layers of sediment.

They then used these images to measure the slip rate within the San Diego Trough Fault Zone, the first slip rate that has ever been recorded for an offshore fault within the California Borderland.

To calculate the fault's slip rate, the researchers first used data from MBARI's Dorado-class, seafloor-mapping AUV to measure how far the fault had shifted the seafloor and found a shift of about 18 meters. To estimate how long this 18-meter shift took to form, the team used sub-bottom profiles and collected samples of sediment using MBARI's ROV Doc Ricketts.

Using the new sonar data, the team also discovered that this fault extends 60 kilometers further north than previously mapped. It may even be linked to the San Pedro Basin Fault Zone, which extends an additional 90 kilometers to the northwest. If this is the case, this fault zone would be one of the longest in the California Borderland and could produce some of the largest earthquakes in the region.

PharmaSea Hunts for Potential Antibiotics in Deep-Sea Trenches
In an effort to uncover bacteria that can produce new antibiotics, the PharmaSea project will plunge up to 2 kilometers below sea level to retrieve samples this autumn in the Atacama Trench in the Eastern Pacific Ocean about 100 miles off the coast of Chile and Peru. The four-year project is backed by £8 million of European Union funding.

The team will also search the Arctic waters off Norway and the Antarctic via Italian and South African partners. Deep trenches will also be accessed off New Zealand.

Using fishing vessels, the team will drop a sampler on a reel of cables to the trench bed to collect sediment. Scientists will then attempt to grow unique bacteria and fungi from the sediment, which can be extracted and refined to discover new antibiotics.

Most experts agree over-reliance and inappropriate prescribing of antibiotics has led to an increase in drug-resistant bugs. Medical experts fear effective antibiotics might soon run out completely, leaving no means to treat seriously ill patients in the future. 'There hasn't been a completely new antibiotic registered since 2003. This is partially because of a lack of interest by drug companies as antibiotics are not particularly profitable,' said project leader Marcel Jaspars, a professor of chemistry at the University of Aberdeen. 'The average person uses an antibiotic for only for a few weeks and the drug itself only has around a five-to-10-year lifespan—so the firms don't see much return on their investment.'

Only a handful of samples have ever been taken from deep trenches and investigated. The results of the project could be available to treat patients within a decade.

Scientists Prototype Titanium Fish Trackers With 3D Printing
The Commonwealth Scientific and Industrial Research Organisation (CSIRO) scientists are using 3D printing to build a new generation of titanium fish tags. The aim is to use the tags to track big fish such as marlin, tuna, swordfish, trevally and sharks for longer periods.

CSIRO is printing the tags at its 3D printing facility in Melbourne, Australia. The tags are printed overnight and then shipped to Tasmania where marine scientists are trialing them. Tags are made of titanium for several reasons: the metal is strong, resists the salty corrosiveness of the marine environment and is biocompatible (nontoxic to living tissues).

One of the advantages of 3D printing is that it enables rapid manufacture of multiple design variations, which can then be tested simultaneously, in as little as a week. CSIRO's 3D printing facility prints metal items layer by layer out of fused metal powder. Had the scientists been using conventional tags, which are machined out of metal blocks, it would have taken a couple of months to design, manufacture and receive the new designs for testing.

Scientists from a number of agencies, including CSIRO Marine and Atmospheric Research, use fish tags to track movements of individual marine species and increase understanding of their behavior.

IOOS Publishes Guide for Ocean Data Standardization
The U.S. Integrated Ocean Observing System (IOOS) has issued the first in a series of IOOS manuals designed to improve standardized collection of ocean data, 'A Guide to Quality Control and Quality Assurance for Dissolved Oxygen Observations in Coastal Oceans.' This standardization of 26 different oceanographic data variables should enhance accuracy of tools, models and forecasts.

The manual, available at www.ioos.gov/qartod, focuses on best practices for quality assurance and control tests of dissolved oxygen measurements taken by commonly used sensors in all coastal regions, including the Great Lakes. The next manuals, expected out this spring, will feature best practices for wave and current data.

Developed with observing experts and sensor vendors, the manual provides a checklist that each IOOS region, as well as others who operate data collection centers, can use to begin quality assurance and control procedures while still addressing specific regional needs.

The effort behind the manuals began in 2003, looking at then-existing community-based quality assurance/quality control efforts and standards across federal agencies and in the development of U.S. IOOS Regional Coastal Ocean Observing Systems.


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