Welcome to SeagrassSoundings Blog

Welcome to SeagrassSoundings Blog



SeagrassSoundings focuses on the work that scientists and managers are doing to protect, preserve, study, restore and monitor seagrass in Massachusetts.


Monday, April 14, 2014

Eelgrass smothered by spring algae bloom in West Falmouth Harbor





The first week in April Mass. Division of Marine Fisheries divers Wes Dukes and Vin Malkoski surveyed our West Falmouth eelgrass monitoring sites and this is what they saw. 
They observed algae coating the eelgrass plants and moorings in a fluffy flocculent layer.  The pictures above are from a site in the outer harbor, where there is more flushing and better water quality than most of the rest of the harbor.  The first two show algae coating the bottom over eelgrass and a mooring line and the third picture is of fouling on a conservation mooring floating rode.  Are we observing the spring macroalgal peak biomass?  Or was this amount of algae here all winter? A study in Waquoit Bay (Fox et al. 2008) showed peak algae biomass from May to June.  However they also found that nitrogen stressed embayments experienced both larger seasonal differences in algae biomass and a larger persistent crop of algae during the seasonal low.  After a long winter which didn't seem to be over in the beginning of April, I wonder if this algae bloom is an early spring bloom or the persistent winter standing cropIf it is the latter, then the biomass of algae may be a warning of further declining conditions to come.

A little bit about bloom-forming algae and nutrient loading:
Benthic and epiphytic algae (Algae on the harbor bottom and growing on eelgrass, etc.) grow rapidly and utilize nutrients quickly, compared to non-bloom, slower growing seagrass.  Therefore they are an indicator of poor water quality and high nutrient loading to a system.  Algal blooms  can shade the water column preventing light from getting to eelgrass plants and eventually killing them.
When algae dies the decomposing process consumes large amounts of oxygen creating an inhospitable environment for many fish and invertebrates as well as eelgrass.

Nutrients can come overland from stormwater and snowmelt, running off lawns and roads, or from the groundwater.  West Falmouth harbor is a eutrophic, ground water-fed estuary.  That means that nutrient (nitrogen) levels are high and that most of the freshwater input is coming from the groundwater.  Estuarine eutrophication can lead to hypoxia (low oxygen), habitat degradation (eelgrass decline), loss of biodiversity and increase in harmful algal blooms.   In 2003 West Falmouth harbor had three times as much nitrogen in the water as it did in the mid 1990s (Thoms et al 2003).   The increased nitrogen was found to be mainly coming from the groundwater plume from Falmouth’s wastewater treatment plant (Thoms et al. 2003). 

In Waquoit  Bay, Fox et al (2008) found that total macroalgal biomass increased with increasing nitrogen loads and that the two dominant macroalgae showed greater biomass in the high nitrogen load systems, while eelgrass was the dominant primary producer only in the low nitrogen estuaries.  Over the last two decades, eelgrass has disappeared from most of the Waquoit Bay estuary and shading by algae, together with degraded water and sediment conditions, is cited as the likely cause.  Will West Falmouth have the same fate?

What do “conservation moorings” have to do with water quality in West Falmouth harbor?
We are now in our second season of a project to test "eelgrass friendly moorings" or "conservation moorings" in West Falmouth harbor.  Below is a picture of the two different systems used in West Falmouth, the Hazelett rode and the Eco-mooring rode with a helix anchor shown too.


We have seen from our work in Manchester Harbor that reducing or eliminating chain drag enables eelgrass to grow in a former mooring scar.  But another consequence may be improved water quality.  The conventional mooring chain stirs up and resuspends the sediment causing increased turbidity (cloudy water) and possibly resuspension of nitrogen back into the water column.  Conservation moorings do no drag on the harbor bottom because they are constructed with floating mooring chain and helix anchors to minimize impacts to the bottom.  So it is possible that minimizing chain drag may reduce suspended turbidity and suspended nutrients in West Falmouth Harbor.

References:
Fox SE, E. Stieve, I. Valiela, J. Hauxwell. J. McClelland.  (2008) Macrophyte abundance in Waquoit Bay:effects of land-derived nitrogen loads on seasonal and multi-year biomass patterns.  Estuaries and Coasts Vol. 31 pp. 532-541

Thoms T, A.E. Giblin, K.H. Foreman.  (2003) Multiple approaches to tracing nitrogen loss in the west Falmouth waste water plume.  The Biological Bulletin, Vol. 205, pp. 242-243

Tuesday, September 10, 2013

Aerial photos reveal boat mooring impacts to seagrass meadows in West Falmouth Harbor



This week I enjoyed a breathtaking flight over Buzzards Bay thanks to a LightHawk donated flight http://lighthawk.org/ flown by pilot David Murphy.  I was focused on West Falmouth Harbor to take aerial photos of the impact of boat moorings on seagrass meadows, as part of a project funded by the Atlantic Coastal Fish Habitat Partnership.  The photos below show the striking mooring scars in the eelgrass bed.  Propeller and rudder scars are also evident. 



MarineFisheries received a grant in 2012 from the Atlantic Coastal Fish Habitat Partnership to continue studying the impact of conventional moorings (anchor and chain) on seagrass meadows, and to test the utility of a new innovative mooring design referred to here as a "conservation mooring".  Previously, we tested conservation moorings installed in Manchester-by-the-Sea and we continue to monitor the mooring scars and measure changes at that location.  The new funding enables us to expand the project to a harbor on the Cape and test the concept in a different system.

Conventional moorings have heavy chain that drags along the bottom, stirring up sediment and ripping out seagrass.  Conservation moorings use floating, flexible line that does not contact the bottom and a helical anchor driven into the sediment for maximum holding power with minimal footprint.  These systems may minimize scouring of the seafloor and reduce impacts to seagrass and water quality. 
A) Conventional Mooring with chain drag; B) Conservation mooring and eelgrass
Left: helical anchor; Middle: Hazelett flex rode; Right: Ecomoorings flex rode
Dave Merrill installing a helix mooring anchor in W. Falmouth
With grant funding, 8 conventional moorings were voluntarily converted at no cost to the owner, to a conservation mooring.  Such conservation moorings have been in use locally for several years already in Marion, Chatham, Tisbury (Vineyard Haven), and Lake Tashmoo, with good reviews from boat owners and harbormasters.  There are several designs and brands of conservation mooring.  Eco-Mooring by BoatMoorings.com, a New England based company, and Hazelett Systems, were chosen for comparison in West Falmouth Harbor.  Dave Merrill of BoatMoorings.com worked together with the local mooring maintainers in West Falmouth to install all 8 moorings in May 2013.





These photos will be our "before" conditions.  Stay tuned in the coming years to see how this seagrass meadow changes.









Friday, August 30, 2013

Restoration in Boston Harbor: Volunteer Event at New England Aquarium

On the unseasonably chilly morning of August 27th, Wes and Jill hit the water early to harvest 4,000 eelgrass shoots from a small cove in Nahant Harbor. The bed looked great: tall, thick and dense with abundant reproductive shoots. When enough plants were harvested, divers stored them in covered totes and steamed by boat to the New England Aquarium’s education building, where 19 volunteers from the Live Blue Ambassador’s program were ready to “get their weave on”.

Jill and Wes kicked off the event with a presentation about the ecology and importance of eelgrass, the work carried out by MarineFisheries eelgrass team, and a quick training session. Volunteers would be using the Burlap Disc (BD) method developed by Chris Pickerell (Cornell Cooperative Extension) to weave 10 shoots into each planting unit.

Volunteers huddled around 6 table-top stations containing shallow totes filled with saltwater. Keeping the plants wet at all times, they tirelessly weaved the eelgrass onto discs (provided by C. Pickerell) which were then placed in a central tote to be skewered and quality controlled by Kate.

Volunteer event in the NEAq Harborside Learning Lab
LBA Participants weaving grass
Kate and Wes skewer and QC the discs
 Previously, we used outdoor venues for volunteer events – so we are grateful that NEAq helped us keep ourselves and the eelgrass out of the direct sun.


Over the course of 2½ hours, the 19 volunteers weaved 390 discs (3900 plants), weaving at a rate of about 8½ discs per person per hour. If our typical 3-person field team tried to weave all this, it would take about 15 hours!

LBA's weaving
Tay helps weave at one of the stations
NEAq's Lucy Indge (background) helps one of the volunteers work through a huge pile of plants
At the end of the event, the finished discs were taken to the Winthrop Harbormaster’s pier and soaked in lobster cars overnight. The team planted the discs over the following 2 days, totaling six 5m x 5m plots at Governor’s Island Flats, with a total expansion area of ¼ acre. We look forward to monitoring the plots in the coming weeks.

For a video file of the presentation, or details about our methods, contact the eelgrass project staff.

Our special thanks to:

Lucy Indge and education staff at the New England Aquarium, Chris Pickerell and the Cornell Cooperative Extension, NEAq Live Blue Ambassadors participants:  Abby Park, Victoria McGovern, Wafa’a Satti, Shirley Ma, Destiny Alfonso, Jiayi Chen, Maegan Allen, Samantha Eschuk, Adam Barriga, Haley LaMonica, Jada Wilhelmsen, Nadina Khudaynazar, Cory Johnson, James Orlic, Nicholas Pioppi, Abigail Muscat, Rachel Borczuk, and Antonia Eidmann. 

Thursday, July 11, 2013

MarineFisheries Hub3 eelgrass restoration mid-project progress report, June 2013



MarineFisheries Seagrass staff recently completed a mid-project status report detailing the background, methods, preliminary results and discussion of our eelgrass planting project in Salem Sound and Boston Harbor, funded as partial mitigation for the Hubline Pipeline impacts to eelgrass. 

You can read the full report on the Fisheries Habitat Program page of the MarineFisheries website.  Click the link below to get there directly.




Hub 3 mid-project report 2010-2012