Environmental Challenges for Extracting U from Seawater

1. Environmental Challenges for Extracting U from Seawater George T. Bonheyo, Ph.D. PNNL Sequim Marine Research Operations george.bonheyo@pnl.gov (360) 681-3678

2. Challenges: Site selection and permitting • Policy for Siting: • Cannot write an EIS without basic information (marine hydrokinetic power example) • Impact of design on benthic ecology – coral reefs are protected • Impact on migratory marine mammals, fish, shellfish • Entanglement of animals • Creation of artificial communities • Grazing, predation, and entry of metals into foodchain • Attracts sportfishing, diving • Leaching of sorbant chemistry • Durability and consequence of breakdown • Impact on current • Impact on other commercial Interests • Finfish and shellfish • Public input

3. Challenges: Site selection and permitting • Policy for Siting: • Who controls near-shore environment site permits: • State • County – impact on local industry • NOAA • Coast Guard • EPA • Potentially ACE • DOE (per energy policies) • Dept of Interior – impact on marine sanctuaries and parks • >30 years to finally determine who controls ballast water policies (for now…) • Need for scaled field testing • Multi-season assessments

4. Biofouling: • Marine biofouling: generally a 4-step process • Surfaces are rapidly coated (beginning in minutes, continuing for hours) with an organic conditioning film of amino acids, peptides, glycoproteins, humic material, lipids, nucleic acids, and other undefined macromolecules • During the second stage, single bacterial cells and diatoms begin to settle, adhere and colonize • During the third stage, microbial films and rough surfaces trap more particles and organisms, including spores of algae, marine fungi, and protozoa. Eventually larval stages of macrobiota settle • Finally, outgrowth of macrobiota occurs.

5. Successive chemistry in fouling • Marine biofouling: Development of coating chemistry • Primary coating and ooze: proteins and peptides first then polysaccharides • Secondary compounds: colonizer-generated polysaccharide complexes, metabolites, nucleic acids • Messenger compounds- quorum sensing, recruiting • Macrobiotic adhesive compounds: proteins (e.g. Mcfp1) and carbohydrates

6. Biofouling: • Potential Impacts of fouling: • Macrofouling- impact on drag and localized current (greater spacing needed- then larger field • Impact on efficiency of extraction (free water exchange on active surfaces) • Microenvironment alteration: potential acidification of surfaces (Cyanobacteria) • Grazing and entry into foodweb • Grazing or metabolic impact on organic ligands • Impact of fouling materials on recovery • Carbonates, silicates, and biomass impact on stripping • Contribution to algal blooms (red tide, coral diseases) • Creation of reef community – attracts predators and man

7. Antifouling: • You cannot stop fouling, but you can delay it • Short duration exposures (<60 day) would be best • Molecular fouling occurs in minutes- may need to assess what would cause your system the most trouble and design out coating to slow the process • U-Extraction process should also include effort to remove foulants • The closer you are to the shore, the greater the problem (nutrient sources, sediments, biomass) • Estuarine areas – fouling within days to weeks