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 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). For the past 25 years, our laboratory has been involved in the development of new uses and improving old uses for seaweeds. For example, we have developed high-temperature tolerant strains of the carrageenophytes Chrondrus and Kappaphyscus, have studied the production of a halogenated monoterpene drug candidate in Ochtodes, and improved the fatty acid composition in Porphyra (nori).

A common theme in our current research is the development of seaweed uses for the protection of the marine environment. We believe that seaweeds have a number of uses in environmental protection that have been underappreciated. For example, we believe that seaweeds have the capability to be an excellent high-protein, high-PUFA feed supplement for fish aquaculture, thereby helping to make fish aquaculture more sustainable and our seafood safer. In addition, we believe that some seaweeds provide an extremely cost effective method for removing a number of wide-spread, toxic organic pollutants in marine sediments, eg. PAHs, PCBs. Lastly, our laboratory is studying the reproductive ecology of the invasive seaweed Codium fragile ssp. tomentosoides as a first step in understanding its abundance at certain sites on Cape Cod. Listed below are details of our current research projects.

1. Seaweed Uptake and Bioremediation of Organic Marine Pollutants:  PAHs, PCBs, and TNT (with undergraduates Jocelyn Mitchell and Anna Meador, 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.
The principal goals of this project are to investigate the capability of seaweeds to take up PCBs and PAHs from marine waters and sediments and the subsequent fate of such compounds in their food chains.

Fig. 1. Ulva lactuca growing on oil-contaminated sediment,
Island End River, Greater Boston Harbor

Initially we examined the uptake of a model PAH (phenanthrene) and a model PCB (3-chlorobiphenyl) in the laboratory. We saw a very rapid uptake and removal of both pollutants from spiked media by the green seaweed Ulva lactuca (“sea lettuce”) collected from an oil-contaminated site in greater Boston Harbor (Fig. 1). The rapid removal by Ulva of a PAH and PCB was similar to what we had previously seen for another organic pollutant, TNT, by Porphyra yezoensis (Cruz-Uribe, Cheney and Rorrer (2007, pdf below). In the latter work, Porphyra yezoensis removed 100% of the TNT in just 72 hrs and started producing metabolites that could be detected by HPLC within 30 hrs (Fig. 2). This work is one of the first to demonstrate the feasibility of using seaweeds as bioremediating agents of toxic organic marine pollutants.

Fig. 2. Bloom of Ulva lactuca in New Bedford Harbor, MA, looking north just above Coggeshall St., July, 2008.


More recently, we discovered that there is a bloom of Ulva lactuca growing in New Bedford Harbor (MA) where the Superfund Site is located. The bloom is caused by excess nutrients coming into the Upper Harbor and is seasonal. Based upon quadrat data, we estimate there was over 18 tons of Ulva found just along the western shoreline of the Upper Harbor in shallow water in July, 2008. The concentration of (total) PCBs in Ulva samples from the Upper Harbor ranged from a high of 98 ppm (taken from nearest the site of Aerovox Corp., where PCBs were used in the production of capacitors & transformers from 1940-77) to a low of ca. 2 ppm (taken from near the entrance of the Upper Harbor). Our highest level (98 ppm) is ca. 800 times greater than the highest levels of PCBs previously reported for any seaweed. We also measured the rate at which they take PCBs up by placing uncontaminated Ulva plants in cages above Aerovox and found they took up 4 ppm PCBs in just 24 hrs, 8 ppm in 48 hrs. Because of the large biomass of Ulva in the Superfund Site and its high PCB levels, we are studying what grazes on Ulva in the Superfund Site and what role it might play in the transfer of PCBs up its food chain.

Fig. 3. 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. 4. 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. 5.  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. 6. 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, in particular slipper shells, might play in its recruitment.

Fig. 7. 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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