For Diers' work, the first step in seeking new antifouling compounds is to expose young zebra mussels to saltwater solutions with increasing concentrations of a given natural compound to determine if their attachment to a hard surface is prevented. Those mussels that do not attach are then removed and placed in a new solution without the compound. If the mussels still do not attach, it indicates that attachment was prevented due to a toxic effect on the mussels. If they do, it indicates the compound had a true antifouling effect, which is more desirable because toxic effects are, of course, more likely to have a detrimental ecological impact.

To further assess potential toxicity to the environment, promising candidates are then tested on duckweed and small fish as a measure of potential environmental impact. This side of the work also has other potential applications, one of which is to further understanding of a given natural product's ecological role and importance to the organism from which it was isolated. For instance, the research allows determination of whether a compound is actually toxic to fish, or simply has a repulsive smell or other noxious characteristic that deters feeding without harming the potential predator. Compounds that are non-toxic but prevent feeding might also be pursued as potential appetite suppressants for humans.

Once an antifouling compound is identified, it is then added to paint and applied to PVC pipes placed in Pearl Harbor for weeks to months to determine their effectiveness in the field. This work is done in collaboration with colleagues at the University of Hawaii. Diers says Pearl Harbor is an ideal location for the work because it is protected from wind and wave action. It is also tropical, meaning that fouling organisms can attach year round, as opposed to temperate U.S. waters where temperatures and weather conditions vary greatly. This allows for reliable, long-term studies.

- VIDEO CLIP 3: "Bioassay Details; Compound Structure-Activity Relationships"

- VIDEO CLIP 4: "Testing Compounds For Ecologically Relevant Properties; Microbial Sources"

So far, Diers has identified about a dozen compounds with strong antifouling potential and minimal toxicity toward non-target organisms. However, in general, their impacts have proven to be short lived. Accordingly, he is working with colleagues at Ole Miss (University of Mississippi) to modify the compounds to increase longevity. Chemists make small modifications to a compound's structure to produce a number of analogs, which are then tested to determine if they retain antifouling potential while being more persistent in the field.

For a compound to be a successful antifoulant, it will have to be relatively cheap to produce because large quantities would be required. Costs that might be feasible for pharmaceutical applications would not be economically feasible for antifouling. So, analogs are only created using modifications that are simple and cheap to accomplish. The primary method used is to add extra carbon chains to the compounds to increase their water-repelling characteristics.

Because zebra mussels pose such a huge ecological and economic threat to waterways, Diers has to take extreme precautions in his laboratory to prevent even the possibility of a zebra mussel release into the water system. In order to obtain permits for the work, Diers has had to physically remove all water and drains in the lab to prevent accidental discharge. In addition, work is done in a locked cage enclosure that prevents entrance of non-trained personnel. All work with the mussels is done in a closed system where the water never reaches any drain or open water source. Experiments are also conducted in a triple container system so that any leak in the primary experimental tank would simply flow into the next container.

- VIDEO CLIP 5: "Promising Compounds, Next Steps; Careful With Those Zebra Mussels!"

Jeffrey Diers received his undergraduate degree from the State University of New York at Fredonia, where his mentor, Dr. David Orvose, introduced him to invasive species. Afterward, he spent several years in research studying the Eurasian watermilfoil, an exotic aquatic plant introduced to North America somewhere around the start of the 1900s. Later, he and colleagues identified a small, invasive fish called the Round Goby that was introduced into the Great Lakes. He then went on to get a master's degree at Buffalo State College while continuing to work with invasive species. Next, he worked for the U.S. Fish and Wildlife Service as a technician before taking his current position at the University of Mississippi.

- VIDEO CLIP 6: "Educational Background"