Microtextured surfacing may help to eradicate the problem of barnacle larvae in the shipping industry

Dec 12, 2011 By Lee Swee Heng
Side view of an exploring cyprid barnacle larva. The attachment disks are the darker spots at the end of the antennules. Credit: A*STAR

The US Navy estimates that biofouling—the accumulation of unwanted marine organisms, such as barnacles and seaweeds, on the hulls of ships—can reduce a ship’s speed by 10% and increase fuel consumption by 40%. Coating the ship’s hull with biocides can help prevent biofouling, but the chemicals used are often harmful to the environment. An environmentally friendly alternative to biocides is the use of microtextured surfaces to which marine organisms have difficulty latching onto.

William Birch and co-workers at A*STAR’s Institute of Materials Research and Engineering1 have now revealed a mechanism by which microtextured surfaces deter marine organisms. The finding could help to develop new artificial surfaces for preventing biofouling.

Previous studies have found that barnacle larvae preferentially settle in cracks and depressions because the voids offer better protection from the currents in which they feed. However, the reason why microtextured surfaces reduce barnacle larvae settlement was unclear. For this reason, the researchers constructed an experimental setup which allows them not only to view the exploration behavior of barnacle larvae on different surfaces, but also to study how the size of surface features influences their surface exploration (see image).

To investigate the impact of surface texture on barnacle settlement behavior, Birch and co-workers fabricated polymer surfaces with features of the same size of a larva’s cyprid attachment pad, which is elliptical in shape and about 20 by 30 microns or thousandths of a millimeter. The surfaces were textured with pillars placed 10 microns apart. The columns were five microns and 30 microns high, and 5, 10, 20, 30, 50 and 100 microns in diameter. A smooth surface without pillars was used as a control. Exploration and settling behavior of the larvae were filmed using close-range microscopy.

The researchers found that barnacle larvae were unperturbed by the five-micron high pillars, as their flexible attachment disks could simultaneously flow over and contact the top of the pillar and the bottom of the space between pillars. Thirty-micron high pillars, however, had a dramatic impact on larval behavior. At smaller diameters, the contact area afforded by the tops of the pillars was small, and the larvae found it difficult to attach to the sides of such slim pillars. At diameters of 30 microns or greater, the larvae tended to form attachment points in the cracks between the columns with their disks wrapping around the sides of the column.

“These and other recent findings have spawned a multidisciplinary research program (Innovative Marine Antifouling Solutions for High Value Applications, IMAS), whose objective is to engineer patterned surfaces and measure performance by quantifying their interactions with marine organisms,” says Birch.

Explore further: Stanford researchers rethink 'natural' habitat for wildlife

More information: Chaw, K. C., et al. Surface exploration of Amphibalanus amphitrite cyprids on microtextured surfaces. Biofouling 27, 413–422 (2011).

Provided by Agency for Science, Technology and Research (A*STAR)

not rated yet
add to favorites email to friend print save as pdf

Related Stories

First images of barnacle larva's footprint

Oct 27, 2008

(PhysOrg.com) -- The fouling or growth of sea organisms, such as barnacles, on ships’ hulls causes damage costing many billions of euros annually. In order to prevent this fouling, In Yee Phang of the University ...

Barnacles prove hard to please when house-hunting

Nov 12, 2008

(PhysOrg.com) -- It’s a tough life out at sea so you might think a small crustacean would be happy to take what it can get when it comes to finding a home - not the humble barnacle.

Gene that causes barnacles to avoid ship hulls identified

Aug 16, 2010

The substance medetomidine has proved effective in preventing fouling of ship bottoms. Researchers at the University of Gothenburg have now identified the gene that causes the barnacle to react to the substance, ...

Specialized seeds can really float your boat

Jul 04, 2011

A new artificial surface inspired by floating seeds, which could provide an alternative to the toxic paints currently used to prevent fouling on ship hulls, has been developed by German scientists.

Recommended for you

Plants with dormant seeds give rise to more species

11 hours ago

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Scientists tether lionfish to Cayman reefs

21 hours ago

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...