Environmental Challenges for Extracting U from Seawater

George T. Bonheyo, Ph.D.PNNL Sequim Marine Research Operationsgeorge.bonheyo@pnl.gov(360) 681-3678

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

o Grazing, predation, and entry of metals into foodchain

o 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

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

Biofouling:

Marine biofouling: generally a 4-step process

1) 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

2) During the second stage, single bacterial cells and diatoms begin to settle, adhere and colonize

3) 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

1) Finally, outgrowth of macrobiota occurs.

Successive chemistry in fouling

Marine biofouling: Development of coating chemistry

1) Primary coating and ooze: proteins and peptides first then polysaccharides

1) Secondary compounds: colonizer-generated polysaccharide complexes, metabolites, nucleic acids

1) Messenger compounds- quorum sensing, recruiting

1) Macrobiotic adhesive compounds: proteins (e.g. Mcfp1) and carbohydrates

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

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