An ecological alternative
Power generation facilities require annual maintenance and prevention programs to keep mussel infestations in their underwater cooling water intake systems under control.
In many of these and other raw water-dependent infested infrastructures, controlled dosages of chlorine or other types of biocides are currently required for this purpose.
Natural resource interest groups and regulatory agencies are reexamining the long-term negative use of biocides for this purpose.
Both groups made it clear that safe and non-chemical alternatives to mussel inlay control would be beneficial to the environment. Chlorination, for example, is a common method of control, and when chlorine combines with organic compounds in water, potentially carcinogenic substances, such as trihalomethanes and dioxins, are formed (United States Environmental Protection Agency).
If future regulatory actions result in the loss of chemical biocides without an alternative control option, electricity generation organizations and many other industries that depend on surface water withdrawal for operational reasons will certainly face economic penalties.
These losses would be the result of reduced production caused by increased plant maintenance and downtime. The availability of an equally effective, yet more environmentally benign mussel control method to replace chlorine and other biocides is fundamentally needed for power plants and other infested facilities.
Bacteria kill mussels
Faced with the threat of zebra mussels messing with electrical power facilities within New York State, the Empire State Electric Power Research Corporation (ESEERCO1) hired the NYSM Field Research Laboratory in 1991 for the screening of bacteria as potential biological control agents.
Extensive trials of laboratory screening of more than 700 bacterial strains identified the CL145A lineage of Pseudomonas fluorescens, as lethal to these mussels. Of the P. fluorescens strains that have been tested in the laboratory to date, only Pf-CL145A has been found to be highly lethal, ie at doses that produce> 90% adult mussel death and 100% larvae.
Pseudomonas protects is distributed all over the world and is present in all bodies of water in North America. In nature, it is a harmless bacterial species that is found protecting from diseases, the roots of plants. NYSM research has shown that the Pf-CL145A lineage of this species may be fortuitously used for another purpose - the control of Dreissena spp. A patent for this purpose was issued in the United States and Canada
Mussels die of a natural product: dead bacteria kill equally
Although phytoplankton is their preferred food, Dreissena mussels can filter and consume bacteria as a food source. When a zebra mussel or quagga ingests artificially high densities of the CL145A strain, however, compounds within these bacterial cells destroy the digestive system of the mussel.
Dead cells are as lethal as living cells, providing clear evidence that mussels die of natural compounds, not infection. Economical methods were developed by MBI to kill bacteria without any reduction in their lethality to mussels. Findings from recent trials and bench tests indicate that MBI significantly increased efficacy against zebra and quagga mussels. Commercial products developed by MBI based on this microorganism, which will be marketed as Zequanox®, contain dead cells, further reducing environmental concerns.
Research Paradigm - Why Microorganisms?
It is widely accepted that screening of various microorganisms and plant species for the natural products they produce is a worthwhile activity due to the discovery of drugs that can prevent or cure animal diseases, particularly cancers. More than 50% of today's medications have been derived from natural sources. Similarly, 11% of the pesticides in use today are derived from plants and microorganisms. Therefore, it makes sense to look at microorganisms for unique natural products that have potential as highly selective biopesticides. In fact, the use of microbial compounds from natural products already has a clear record of commercial success and environmental safety in invertebrate pest control in North America as well as globally (Rodgers 1993). The New York State Museum's (NYSM) laboratory has been involved in such research for more than two decades. Marrone Bio Innovations, the commercial developer of this mussel control product, has a team of scientists and a management team that has been involved in the biopesticide industry since its inception and is recognized as a leader in research, development and marketing of "chemical green". The MBI team has successfully introduced a number of biopesticides in the domestic and international markets over the last thirty years.
List of toxicology studies that were conducted with Zequanox® in order to guarantee its selectivity to the mussels. The studies were conducted by Marrone Bio Inovation in certified contracted laboratories and a number of research organizations, including the New York State Museum and the United States Geological Survey.
The conclusions of the various studies show that Zequanox is highly selective for mussels and is safe for
many aquatic species, including fish, native seaweeds, plants, algae, crustaceans and insects, as well as, real ducks.
In addition, the US EPA described the active ingredient in Zequanox as follows:
"The protective Pseudomonas strain CL145A (Zequanox) has low toxicity and presents little risk to non-target organisms" [US EPA
Biopesticide Registration Action Document (BRAD) July 29, 2011].
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(Lepomis macrochirus
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Ictalurus punctatu
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(Oncorhynchus tshawytscha
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Salvelinus fontinalis
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Cyprinus carpio)
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Pimephales promelas
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(Catostomus sucker spp
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Acipenser fulvescens
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Micropterus salmoides
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Oncorhynchus mykiss
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Pogonichthys macrolepidotus
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Micropterus dolomieu
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Morone saxatilis
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Sander vitreus
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Perca flavescens)
Mytilus edulis
Anadonta
Ligumia recta
Lampsilis siliquoidea
(Lampsilis abrupta
Obovaria olivaria
Lampsilis higginsii
Actinonaias ligamentina
Lampsilis cardium
Megalonaias nervosa
Margaritifera falcata
Lymnaea peregra