In-lake Prevention Strategy
Substantial Supporting Field Data
Barley straw (Hordeum vulgare) has been used for over four decades to prevent the growth of cyanobacteria. Initial reports showed widespread success in the United Kingdom, and barley straw deployment has spread to the United States in the past 20 years (Sellner and Rensel 2018). Decomposition of barley straw leads to the breakdown of lignin-containing cell walls within the straw. Lignin decomposition produces two types of residues that limit cyanobacterial growth. Some are specific compounds that individually inhibit cyanobacteria, while others yield strong oxidizing agents that rapidly reduce cell viability. For details and examples, please see Huang et al. (2015), Matthijs et al. (2012), Pillinger, Cooper, and Ridge (1994), Ridge and Pillinger (1996), Xiao et al. (2010), and Xiao et al. (2014).
The general procedure is as follows: 1–1.5 months prior to an expected HCB, stake or otherwise secure <1-year-old, fungicide-free bales of barley straw into the littoral zone of ponds, lakes, or incoming streams. Bales should be applied at a rate of 7 bales/acre, with several bales saved to deploy halfway through the summer. Bales should be reapplied each year thereafter, again saving some bales for mid-summer deployment. Ranges for barley straw treatment of cyanobacteria in other systems are 6–50 mg barley straw/L in longer residence time waters, such as lakes or reservoirs (Sellner and Rensel 2018).
- Water body type: Pond, lake/reservoir, bay/estuary
- Any surface area or depth
- Any trophic state
- Any mixing regime
- Water body uses: Recreation, potentially drinking water sources
NATURE OF HCB
- All HCB types in ponds to estuaries
- Singular or repeating HCBs
- Toxic and nontoxic HCBs
- Prevention strategy
This technique (7 bales/acre) is effective for most ponds, lakes, reservoirs, and low-salinity estuarine areas and is even more effective if enriched with fungi to aid in lignin decomposition (Sellner et al. 2015). There are some concerns about tannin removal in drinking water facilities from decomposing straw. This technique will not work if applied after the HCB has appeared, and it will not be as effective if the bales are placed in low-light or dark areas. Straw is used in eutrophic systems where blooms have historically occurred; hence, their decomposition results in minimal nutrient additions relative to available levels for bloom growth.
- Effective for most HCBs
- Prevents HCBs and, therefore, any toxin accumulations
- Used in many areas
- Cost is low if bales are purchased from a farmer
- Securing bales along the shoreline is easy
- No impact on submersed plants or fish
- Is an unregistered algaecide, so may be deployed by individuals, groups, etc., but not by licensed applicators
- Will work on most systems, but very large lakes would require significant staff effort for bale deployment
- Possible open-water obstruction, so the U.S. Army Corps of Engineers may need to be contacted
- Straw decomposition products include tannins, a concern for removal in drinking water facilities
- A small mid-summer bale addition may be required
- Some biological oxygen demand accompanies straw decomposition, possibly affecting dissolved oxygen levels, but this is overcome by nearshore deployment, where reoxygenation is continuous
- Some lake organizations object to bale use due to aesthetics
Figure C-1. (A) Barley straw lining a stream entering an HCB-dominated lake in eastern Maryland and (B) along the shoreline of a brackish lagoon in Chesapeake Bay.
Source: A–Place, B–K. Sellner. Used with permission.
Other similar options are found in Effiong et al. (2020): Rice straw inhibits Microcystis aeruginosa in the laboratory (Park et al. 2006), was used effectively in Nile tilapia ponds (Eladel, Abd-Elhay, and Anees 2019, Shahabuddin et al. 2012), and inhibited Anabaena in laboratory experiments (Eladel et al. 2019). Using lake water in aquaria, Tomasko, Britt, and Carnevale (2016) reported that dried cypress leaves at 1.51 g/39 L were more inhibitory to cyanobacteria than equal additions of barley straw.
CASE STUDY EXAMPLES
Williston Lake, Denton, Maryland, United States: 500 barley straw bales were deployed over 67 acres of an incoming stream and shoreline of Williston Lake from April to May while the lake was partially drained, resulting in the lake remaining free of Microcystis aeruginosa. Microcystin and anatoxin-a concentrations were below recreational exposure levels in the first year, followed by absence of the species and toxins in subsequent years (Sellner et al. 2015).
Ponds, drainage ditches, and lakes, United Kingdom and Ireland: Barley straw was effective in reducing Oscillatoria agardhii from 10,000 filaments/mL to nondetectable levels in a 6-ha lake after 3 weeks of exposure. Lake managers for 29 other water bodies indicated dramatic cyanobacteria reductions following barley straw additions (Newman and Barrett 1993).
Potable water reservoir, Aberdeen, Scotland: Approximately twice/year barley straw treatment (6–28 g/m3) of a reservoir from 1993 to 1998 substantially reduced cyanobacteria (Barrett, Littlejohn, and Curnow 1999).
Derbyshire Reservoir, United Kingdom: Cyanobacteria were significantly reduced when 50 g/m3 and 25 g/m3 of barley straw were added to a disused UK water supply reservoir (Everall and Lees 1996, 1997).
Pond, Dublin, Ireland: Barley straw additions (25–50 g/m2) to the pond at the Tolka Valley Park in Finglas, Dublin, prevented growth of Lyngbya mats (Stack and Zhao 2014).
Costs for fungicide-free barley straw bales from farmers are inexpensive relative to retail prices from landscape or pond supply companies, where they can cost five to 10 times more. Implementation requires labor to secure bales in the littoral zone and may require a small mid-summer bale addition.
Cost analysis per growing season: Barley straw
|ITEM||RELATIVE COST PER GROWING SEASON|
REGULATORY AND POLICY CONSIDERATIONS
The only limitations for bale deployment are aesthetics (viewsheds) and boating obstructions if bales are secured in open water.
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Effiong, Kokoette, Jing Hu, Caicai Xu, Tao Tang, Haomin Huang, Jiangning Zeng, and Xi Xiao. 2020. “Sustainable utilization of agricultural straw for harmful algal blooms control: a review.” Journal of Renewable Materials 8:461-483. doi: 10.32604/jrm.2020.09111.
Eladel, Hamed, Mohamed Battah, Aida Dawa, Reham Abd-Elhay, and Doaa Anees. 2019. “Effect of rice straw extracts on growth of two phytoplankton isolated from a fish pond.” Journal of Applied Phycology 31 (6):3557-3563. doi: 10.1007/s10811-019-01766-0.
Eladel, Hamed Mohamed, Reham Abd-Elhay, and Doaa Anees. 2019. “Effect of rice straw application on water quality and microalgal flora in fish ponds.” Egyptian Journal of Botany 59 (1):171-184. doi: 10.21608/ejbo.2018.4852.1199.
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Huang, Haomin, Xi Xiao, Anas Ghadouani, Jiaping Wu, Zeyu Nie, Cheng Peng, Xinhua Xu, and Jiyan Shi. 2015. “Effects of natural flavonoids on photosynthetic activity and cell integrity in Microcystis aeruginosa.” Toxins 7 (1):66-80. doi: 10.3390/toxins7010066.
Matthijs, H. C., P. M. Visser, B. Reeze, J. Meeuse, P. C. Slot, G. Wijn, R. Talens, and J. Huisman. 2012. “Selective suppression of harmful cyanobacteria in an entire lake with hydrogen peroxide.” Water Res 46 (5):1460-72. doi: 10.1016/j.watres.2011.11.016.
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Sellner, Kevin, Allen Place, Ernest Williams, Yonghui Gao, Elizabeth VanDolah, Michael Paolisso, Holly Bowers, and Shannon Roche. 2015. “Hydraulics and Barley Straw (Hordeum vulgare) as effective Treatment Options for a Cyanotoxin-Impacted Lake.” International Conference on Harmful Algae.
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Shahabuddin, A. M., M. Oo, Y. Yi, Dhirendra Thakur, Amrit Bart, and J. Diana. 2012. “Study about the effect of rice straw mat on water quality parameters, plankton production and mitigation of clay turbidity in earthen fish ponds.” World Journal of Fish and Marine Sciences 4:577-585. doi: 10.5829/idosi.wjfms.2012.04.06.6515.
Stack, John, and Yaqian Zhao. 2014. “Performance assessment of an integrated constructed wetland-pond system in Dublin, Ireland ” Journal of Water Sustainability 4 (1):13-26.
Tomasko, David, Mike Britt, and M. Carnevale. 2016. “The ability of barley straw, cypress leaves and L-lysine to inhibit cyanobacteria in Lake Hancock, a hypereutrophic lake in Florida.” Florida Scientist 79:147-157.
Xiao, X., H. Huang, Z. Ge, T. B. Rounge, J. Shi, X. Xu, R. Li, and Y. Chen. 2014. “A pair of chiral flavonolignans as novel anti-cyanobacterial allelochemicals derived from barley straw (Hordeum vulgare): characterization and comparison of their anti-cyanobacterial activities.” Environ Microbiol 16 (5):1238-51. doi: 10.1111/1462-2920.12226.
Xiao, Xi, Ying-xu Chen, Xin-qiang Liang, Li-ping Lou, and Xian-jin Tang. 2010. “Effects of Tibetan hulless barley on bloom-forming cyanobacterium (Microcystis aeruginosa) measured by different physiological and morphologic parameters.” Chemosphere 81 (9):1118-1123. doi: 10.1016/j.chemosphere.2010.09.001.