Research Description

General Objectives

Today, when one hears about algae, it’s almost always in regard to  “harmful algae.” However algae, particularly marine macroalgae or seaweeds, have historically had a number of beneficial uses for mankind. For example, they have long been used as sources of water-thickening hydrocolloids (eg carrageenan and agar), as well as sources of food (eg nori used in sushi). Our laboratory has always been at the cutting edge of developing new and improving old uses for seaweeds. Over the past twenty-five years, we have worked on such things as the aquaculture and genetic improvement of the carrageenophytes Chrondrus and Kappaphyscus, the production of a halogenated monoterpene drug candidate in Ochtodes, and improving the fatty acid composition in world’s most widely eaten seaweed Porphyra (nori).

1. Seaweed Uptake and Bioremediation of Organic Marine Pollutants:  PAHs, PCBs, and TNT (with undergraduates Matthew Brudner and Jocelyn Mitchell, collaborators Greg Rorrer and Tavi Cruz-Uribe (Oregon State),  Kevin Gardner and Deana Aulisio (Univ. New Hampshire)

The two most common organic pollutants in marine sediments today are PCBs (polychlorinated biphenyls) and PAHs (polycyclic aromatic hydrocarbons). Both pollutants pose a threat to marine organisms, as well as to humans that consume contaminated finfish and shellfish. Current methods for eliminating toxic compounds like PAHs and PCBs from contaminated marine sediments require excavation or dredging of the sediment and its disposal, which make their use generally cost prohibitive for many contaminated sites.

Fig. 1. Ulva lactuca growing on oil-contaminated sediment in

greater Boston Harbor

Results from preliminary experiments conducted with a model PAH  (phenanthrene) and with a model PCB (3-chlorobiphenyl) are promising. In both cases, we see a very rapid uptake and removal of the pollutant from spiked media by our best seaweed candidate to date, a strain of the green seaweed Ulva lactuca (“sea  lettuce”) collected from an oil-contaminated site in greater Boston Harbor (Fig. 1). Ulva appears to be able to tolerate and take up high concs. of both PAHs and PCBs and has the advantage that it could be easily deployed in the field as an environmentally-safe bioremediation system. Details of our preliminary uptake experiments with PCBs and PAHs are described in the Cheney et al 2007 abstract (see below). Uptake and metabolism  by seaweed of another organic pollutant, TNT, was described by Cruz-Uribe, Cheney and Rorrer (2007, pdf below). In this latter work, Porphyra yezoensis removed 100% of the TNT in just 72 hrs and started producing metabolites that we could detect by HPLC within 30 hrs (Fig. 2). The latter work helps to prove the feasibility of using seaweeds as bioremediating agents of toxic marine organic pollutants.

Fig. 2. Uptake and metabolism of TNT in native Porphyra yezoensis

2. Development and Evaluation of a Seaweed Feed Supplement for use in Salmonoid Aquaculture (supported by USDA Aquaculture Program & WHOI Sea Grant Program)

 (with graduate students Tim Hogan and Angela Silvestro, and collaborators Fred Barrows (Hagerman Fish Culture Experiment Station. ID) and Joe Buttner (Cat Cove Marine Laboratory, MA)

Fig. 3. Model of an Integrated Porphyra – Fish Aquaculture System

In the past, we developed a strain of Porphyra yezoensis and set of culture conditions for high PUFA production. The total fatty acid profile is very similar to that found in fish typically used for fish oil (eg. herring and anchovy) and shown to be essential for proper fish growth. In our feed evaluation study, we determined the palatability and digestibility of using Porphyra yezoensis in a rainbow trout diet. The experimental diet contained 30% seaweed and showed similar palatability, specific growth rate and feed conversion ratios to that of a reference diet (Fig. 4). Additionally, manually stripped fecal samples revealed that nutrient ADCs (Apparent Digestibility Coefficients) of protein, lipid and phosphorous were high in the experimental diet, while those of nitrogen-free extracts (NFE) and total energy were low. Overall, the results of this study were promising and suggest that Porphyra would be a good candidate for further investigation into the use of seaweed as a fish meal supplement.

Fig. 4.  Feeding behavior of trout on a Porphyra-supplemented

feed vs control feed

3. Biochemical and Molecular Studies on Seaweed Adaptation to Extreme Environmental Conditions – Desiccation and Cold Temperatures

 (with graduate students Yen-Chun Liu and Angela Silvestro)

Fig. 5. Rate of desiccation in the lab of two Porphyra species with

different desiccation tolerances

4. Studies on the Reproductive Ecology of the Invasive Green Seaweed Codium fragile spp. tomentosoides.

 (with graduate student Chris McHan)

Codium fragile spp. tomentosoides (Fig. 6) is the most wide-spread and abundant invasive seaweed along the western N. Atlantic Ocean. Today, it fouls beaches and threatens eelgrass beds in numerous towns on Cape Cod and the Islands, and is starting to appear in abundance on beaches on Cape Ann. Although there have been numerous studies on the physiology and abundance of this invasive species, very little is understood about its reproductive ecology. The primary objectives of this study are to determine the primary mode of reproduction of Codium fragile spp tomentosoides at sites on Cape Cod, and to investigate the role that biological substrates like scallop and slipper shells play in its recruitment.

Fig. 6. Codium fragile spp. tomentosoides found on Wingersheek Beach, Gloucester, MA

5. Past Strain Improvement Studies of Seaweeds for Enhanced Value and/or Growth Traits

We have many years of experience in successfully growing red seaweeds at various scales and improving both their growth and biochemical traits. By developing such techniques as axenic culture methods, protoplast fusion, tissue culture and mutagenesis, we have produced strains of the following genera with one or more improvements:

1. Faster growth rate - Porphyra, Eucheuma, Kappaphycus
2. Altered polyunsaturated fatty acid (PUFA) composition – Porphyra
3. Enhanced tolerance to high temperature – Porphyra, Kappaphycus
4. Enhanced tolerance to low salinity - Porphyra

Press Releases

1. "A seaweed soaks up TNT - and may help clean oceans," Christian Science Monitor, March 24th, 2005.
www.csmonitor.com/2005/0324/p14s02-sten.html

2. “Seaweeds have an appetite for TNT,” Chemical and Engineering News, Feb. 28th, 2005. Download PDF

Selected Publications

Cruz-Uribe, O., Cheney, D., and Rorrer, G. 2007. Comparison of TNT removal from seawater by three marine macroalgae. Chemosphere 67: 1469-1476. [PDF]

Reddy, C.R.K., Dipaklore, S., Kumar, R., Jha, B., Cheney, D. and Fujita, Y. 2006. An improved enzyme preparation for rapid mass production of protoplasts as seed stock for aquaculture of macrophytic marine green algae. Aquaculture 260: 290-297.

Rorrer, G. and Cheney, D., 2004. Bioprocess engineering of cell and tissue cultures for marine seaweeds. Aquacultural Engineering 32: 11-41.

Waaland , J.R., Stiller, J. and Cheney, D., 2004. Macroalgal candidates for genomics. Journal of Phycology 40 (Jan.) 26-33.

Polzin, J., Rorrer, G. and Cheney, D., 2003. Metabolic flux analysis of halogenated monoterpene biosynthesis in microplantlets of the macrophytic red alga Ochtodes secundiramea. Biomecular Engineering 20:205-215.

Hurtado, A. and Cheney, D., 2003. Propagule production of Eucheuma denticulatum (Burman) Collins et Harvey by tissue culture. Botanica Marina 46: 338-341.

Cheney, D., I. Levine, and L. Graham, 2002. Salmon hatchery - discharge water bioremediation and profitable seaweed culture. Fish Farming News, Vol 10, May/June : 37-39.

Cheney, D., Graham, L., I. Levine, I., and G. Rorrer, 2001. Land-based seaweed aquaculture system for remediation of poultry and swine wastewater. In: Addressing Animal Production and Environmental Issues, Havenstein, G. (Ed.), North Carolina State University College of Agriculture and Life Sciences, Vol. 2: pp. 653-657.

Cheney, D., B. Metz and J. Stiller, 2001. Agrobacterium-mediated genetic transformation in the macroscopic marine red alga Porphyra yezoensis. J. Phycol. Suppl. 37: 11.

Rorrer, G., M. Tucker, Cheney, D. and S. Maliakal, 2001. Bromoperoxidase activity in mircoplantlet suspension cultures of the macrophytic red alga Ochtodes sircundiramea. Biotechnology & Bioengineering 74: 389-395.

Maliakal, S., D. Cheney and G. Rorrer, 2001. Halogenated monoterpene production in regenerated plantlet cultures of Ochtodes secundiramea (Rhodophyta, Cryptonemaiales). J. Phycology 37: 1010-1019.

Watson, K, D. Cheney, and I. Levine, 2000. Biomonitoring of an aquacultured introduced seaweed, Porphyra yezoensis (Rhodophyta, Bangiophycidae) in Cobscook Bay, Maine, USA. In: Maine Bioinvasions: Proceedings from the First National Conference, J. Pederson,( ed), MIT Sea Grant Program, pp. 260-264.

Kunimoto, M., H. Kito, Y. Yamamoto, D. Cheney, Y. Kaminishi and Y. Mizukami, 1999. Discrimination of Porphyra species based on small subunit ribosomal RNA gene sequence. J. Applied Phycology 11: 203-209.

Cheney, D.P. 1999. Strain improvement of seaweeds thru genetic manipulation: current status. World Aquaculture 30: .55-56 &65.

Cheney, D.P., 1999. Developing seaweed aquaculture in the northeast US and Canada.: species and strain improvement. Bull. Aquaculture Assoc. of Canada 99-1:23-26.

Huang, Y., S. Maliakal, D. Cheney and G. Rorrer, 1998. Comparison of development, photosynthesis and growth of filament clump and regenerated microplantlet cultures of Agardhiella subulata (Rhodophyta, Gigartinales). J. Phycology 34: 893-901.

Rorrer, G., R. Mullikin, B. Huang, W. Gerwick, S. Maliakal and D. Cheney, 1998. Production of bioactive  metabolites by cell and tissue cultures of marine macroalgae in bioreactor systems. In: Plant cell and tissue culture for food ingredient production. T.-J. Fu, G. Singh and W. Curtis (eds.), Plenum Press, pp. 165-184.

Graber, M., W. Gerwick and D. Cheney, 1996, The isolation and characterization of  Agardhilactone, a novel oxylipin from Agardhiella subulata. Tetrahedron  Letters 7:4635-4638.

Cheney, D. B. Rudolph, L. Wang, B. Metz, K. Watson, K. Roberts and I. Levine, !998. Genetic manipulation and strain improvement in commercially valuable red seaweeds. In: New developments in marine biotechnology, Y. Le Gal and H. Halvorson, (eds.), Plenum Press, NY, pp. 101-104.

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