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Water Quality Impacts on MacroalgaeA.K.A. Seaweed Lesley Lambert

As you drive by the water, which in Rhode Island, is just about everywhere, you experience a fresh, salty or briny aroma. But not always. Some days the seaside breeze caries a pungent smell of rotting fish or seaweed. The reasons for this are mostly natural causes, but human influence tends to exacerbate the problem.

What is that rotten smell?After a storm, many Rhode Island beaches have piles of

seaweed along the shore. On a hot day, just a little breeze can carry the smell for miles inland, never mind the noxious stench right at the beach. So just what exactly is that smell? As seaweed begins to decompose, the molecules of the pro-teins that make up its tissues are torn apart and recycled into other compounds. Hydrogen sulfide (H2S) a gas with unpleasant odors that can be harmful to humans and pets in high concentrations is a byproduct of the decomposition of organic materials.Decaying seaweed is not the only source of hydrogen sul-

fide. The gas is part of the natural environment, but certain human activities produce it in much higher volumes. Many industries such as petroleum refineries, paper and textile mills, and food processing plants produce hydrogen sulfide as a byproduct. We even produce it in our large intestines! Social networking and review sites such as Yelp have shown that the high concentration of seaweed on a beach impacts the beach-going experience and thus the tourism industry. Complaints of rotting seaweed on Rhode Island beaches have increased over the years. The reason there is so much seaweed washing up on our

shores can be traced back to the things we do on the land. Discharge from wastewater treatment facilities and storm drains eventually finds its way into the Bay and the nutrients carried in these waters act as fertilizer to algae and seaweed. The nutrients coming into the Bay from our rivers and storm drains fertilize algae and cause it to bloom uncontrollably, but not in the same, beautiful way your garden flowers. Seaweed soaks up nutrients such as nitrogen and phos-

phorous in the water and it can grow very fast, rapidly overwhelming shallow areas such as Greenwich Bay, Conimi-cut Point or the Seekonk River. When the tides wash mats of seaweed up on the shore, sunlight bakes it on the outside while sulfur-bacteria speed up decay from the inside, produc-ing that smelly hydrogen sulfide gas. The most common green seaweed we find here in Rhode

Island is sea lettuce (Ulva spp.) but there are many other spe-cies of green seaweed and even more that are red and brown. While seaweed provides shelter and structure from predators

Sandy Point in Greenwich Bay is often covered in smelly seaweed that can be several inches thick. Former intern NBEP, Rebecca Sacks, is perfoming ground truthing to determine the species and total biomass of the seaweed in this area Photo: NBJ.

for juvenile fish, dense mats can block sunlight and reduce flow and mixing of waters.Few animals feed or can even survive underneath dense

seaweed mats. Many of the essential bottom habitats for invertebrates such as crabs, shellfish, shrimp and worms become unsuitable in the summer as algae and seaweed blanket the shallow areas. If these seaweed carpets are too dense, these areas become less valuable as feeding grounds to animals such as wading birds, fish, crabs and other preda-tors. Furthermore, as the seaweed decomposes, the nutrients locked up in their tissues are released back into the water, starting the cycle all over again.Since 2006 the Narragansett Bay Estuary Program has

been tracking the amount and species of macroalgae in the western side of Narragansett Bay. Aerial photography from monthly helicopter flights in the summer months allows us to detect areas with high volumes of seaweed. Through a specially designed plug in for a program called Image J, our interns are able to quantify and map how much seaweed is in the Bay and where. This effort is providing a baseline under-standing of how much, what kind and where seaweed is.

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Having this baseline knowledge will allow us to track the changes and potential reduction of the amount of seaweed as sewage treatment plants upgrade their facilities to remove nutri-ents before discharging into the Bay.

State Response to SeaweedThe R.I. Department of Environmental

Management (R.I. DEM) is responsible for investigating Bay-related environmental problems and coordinating with cities and towns to respond to issues relating to marine debris, such as seaweed and dead fish, wash-ing up on our shores, causing noxious odors and elevated bacteria levels. In 2006 R.I. DEM purchased a specially designed tractor to rake up excess seaweed along beaches. This beach cleaner, known as a Barber Surf Rake, drives along the shoreline and removes the seaweed and other debris that has collected above the low tide line. The R.I. DEM Office of Emer-gency Response has teamed up with the Cities of Warwick, Cranston and East Providence to prevent seaweed-prone beaches such as Conimicut Point, Stillhouse Cove and Riverside Terrace from becoming hydrogen sulfide stink holes in the summer months. Once the seaweed is removed, it is disposed of as yard waste by the towns Department of Public Works. Other beaches throughout the state also rake their beaches to keep them clean and seaweed free for the public to enjoy. The public is also encouraged to collect seaweed in areas where their equipment cannot reach and put it in yard waste bags to be

The Combined Sewer Overflow (CSO) Project, also known as the biggest project you will never see is a three-plus-mile-long, 30-foot-diameter tunnel that runs 250 feet below the city of Providence. Photo: NBC.

The Barber Surf Rake is a tractor-towed mechanical rake that is capable of picking up extremely fine debris from bits of seaweed to cigarette butts. Photo: R.I. DEM.

collected by the local public works department. Extensive efforts by the Narragansett Bay Commission

(NBC) and other wastewater treatment facilities around the state to increase nutrient removal in sewage and decrease bacteria pollution by stormwater are beginning to payoff. The NBC owns and operates the two largest wastewater treatment facilities in the state, Fields Point and Bucklin Point, which discharge into the Providence and Seekonk Rivers, respectively. In 2006, extensive upgrades focus-ing on nutrient removal were completed at the Bucklin Point Facility. The nutrient removal upgrades at the Fields Point Facility are currently ongoing, as well as additional upgrades at Bucklin Point. Both facilities are expected to be complete by 2014. Furthermore, R.I. DEM is requiring upgraded treatment to include nitrogen removal at 11 dif-ferent wastewater treatment facilities throughout the state. To address stormwater, the NBC instituted Phase I of the

combined sewer overflow (CSO) abatement program, which included the installation of a three-mile long tunnel 300 ft underground to capture sewage contaminated stormwater. Prior to the NBC CSO Tunnel, stormwater would enter the sewage collection system and overwhelm the sewer system in Providencecausing a mix of untreated sewage and stormwater to be discharged to the urban rivers and the Bay. Since the tunnel went on-line, over 4 billion gallons of polluted water has been captured, treated and discharged to the Baypreventing more than 94 thousand pounds of nitrogen and 41 thousand pounds of heavy metals such as iron, lead, copper, aluminum, and cyanide from polluting our waters. NBCs CSO tunnel project cost $359 million, which may seem like a large investment, but it has made a

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real difference in cleaning waters that were, just a genera-tion ago, written off as permanently polluted. Because stormwater plays such a large role in the trans-

port of pollution to our rivers and oceans, state agencies have developed the R.I. Stormwater Manual (2010) to aid towns and municipalities in developing and retrofitting infra-structure that will prevent pollution and degradation of our waterways. Decreasing these sources of pollution will greatly reduce the amount of beach and shellfish closures and the amount of seaweed that beach-goers must paddle through. There are other sources of pollution we cannot easily mea-

sure or regulate, but still contribute to the degradation of our local waterways. This is the pollution that comes from our individual activities. Cesspools, septic systems, over-fertilized yards and farms, and lazy pet owners who leave behind pet waste can all release bacteria and excess nutrients and other chemicals into the ground and nearby streams and pondspolluting our waterways (and sometimes our drink-ing water)with all eventually reaching the Bay.

What Can You Do?The things you do in your backyard affect the environ-

ment. If you live in Rhode Island, chances are, you dont live more than five miles from a body of water that eventually flows into Narragansett Bay. Fertilizing your lawn can affect the Bay if you are doing

it on a frequent basis or if it rains shortly after you apply it. Studies have shown that fertilizers are only needed to jump-start the growing cycleover-fertilizing will result in fighting weeds and taxing your lawnmower more than the average gardener. There are other ways of keeping your garden and yard vibrant and healthy without using exces-sive fertilizers. Many varieties of native plants have thrived in New England for centuries and do not require extra care in the way of fertilizers or water. If you do need to fertilize, take the time to learn about

your nearest waterway and find a fertilizer that impacts it the least. Freshwater systems are phosphorous-limiting, meaning they require more phosphorous to maintain a bal-ance, while saltwater systems are nitrogen limiting. There are many all-natural fertilizers that will not impact the environment but still enhance the growth of your plants.For the adventuresome gardener, seaweed can actually be

a great fertilizer! Seaweed is rich in nutrients and miner-als essential to plant growth. The Native Americans used it and taught the colonials about its significance. In fact, the R.I. constitution goes so far as to stipulate citizen rights of way to the shoreline, specifically for access to collect sea-weed. It can be used to make a liquid fertilizer or dried and mixed into the soil. There are many recipes and how-to videos online that can help you pick the best method for your garden. Seaweed fertilizer is all natural, easy to use, and you can find it for free at the nearest beach! It may go without saying, but motor fluids, household

cleaners and personal care products are also pollutants harmful to marine life. And of course trash, such as plastic bags, cans, bottles and food wrappers litter our environment and are often mistaken for food by wildlife. Trash should always be disposed of in the proper receptacle to preserve the beauty, health and integrity of our environment. Remember, everything you do on land can impact the nearest waterway, and in Rhode Island, it all finds its way to the Bay.

Go Deeper!Before you pack up the car for a beach day, be sure to check on the Department of Healths Beach Closures and Advisories website www.ribeaches.org/closures.Rhode Islanders can also listen to updates on the overall health of the Bay on Bay Line (401) 222-8888, DEMs 24-hour telephone recorded information service. If you suspect seaweed is causing noxious odors in your neighborhood call DEMs Office of Compliance and Inspections at 222-1360 (weekdays) or after hours/weekends at 222-3070.The NBC has a wealth of information on their many programs, such as the CSO Abatement Program, Wind Turbine Project and their extensive water quality moni-toring of the Upper Bay www.narrabay.com and snapshot.narrabay.com.Download the RI Stormwater Design and Installation Manual.The URI Outreach Center is a great resource for sustain-able agriculture and offers a wide variety of workshops, training and information on gardening in Rhode Island. www.uri.edu/cels/ceoc/index.

Seaweed can be used in your garden as fertilizer and mulch as shown here in FarmTinas Garden. Photo: Martina Fugazzotto.

~Lesley Lambert is the digital communications mangaer for NBEP.