A Conversation with marine biologist Phil Colarusso about coastal memory, experimental restoration, and the future of Massachusetts seagrass
Interview and introduction by Nedret Andre
In the shallow water behind Winthrop Beach’s historic breakwaters, marine scientists are testing new ways to restore eelgrass, one of the Massachusetts coast’s most important and threatened habitats. I recently joined marine biologist Phil Colarusso and a team of researchers as they transplanted eelgrass shoots into a protected site just outside of Boston Harbor. The special team included, Randal Huges, Alyssa Novack and students from both BU and NorthEastern.
For Phil, the project is also personal. He grew up in Winthrop, exploring tide pools and witnessing the devastating Blizzard of 1978. We spoke about why this location was chosen, how the restoration experiment works, the surprising return of a nearby natural meadow, and what persistence could make possible for Massachusetts eelgrass by 2040.
Why Restore Eelgrass in Winthrop?
Nedret Andre: Why is this particular site so important?
Phil Colarusso: I have my early childhood memories , I grew up Winthrop, I am a little biased, more importantly the site was funded from a Boston Harbor project.
They run electrical cables across the harbor to Deer Island. Near the airport they clipped an acre and a half of seagrass meadows, they were required to mitigate for that, they wanted to do the mitigation closest to the impact site. Winthrop is very close to the impact site and there is a natural meadow very close where we were transplanting to. So we think the water quality is good, the sediment quality is good, and by working inshore of those breakers we are thinking that the transplants will be protected from storms. Hoping these transplants will take and thrive.
How the Five Sisters Shaped a New Habitat
Nedret Andre: The location we were at looked a little sci-fi, or man made with rocks everywhere, not really sandy, are they man-made?
Phil Colarusso: Yes, they are all man made, they were put in in the 30’s a part of the WPA project. They were put in to protect the shore line to protect from storms out of the North East.
Note: the offshore breakwaters of Winthrop Beach are known as “Five Sisters”
The structure consists of five detached, segmented concrete and stone breakwaters placed parallel to the shore
Nedret Andre: I noticed a bunch of periwinkles, mussels, and other mollusks while walking to the restoration site. Does this man-made jetty still work like an embayment or bay?
Phil Colarusso: The hydrology of the coast has changed there. Before the breakers were put in( I wasn’t around at that time in1938), you can imagine that entire beach would be hammered with storms from the North East. Having grown up there and experienced the epic Blizzard of 78, I know a lot of the beach area floods. So those breakers are put in to dissipate some of the wave energy and protect the property on the shore drive in particular. It creates these quiescent areas behind it.
All of the sandbars behind the breakers developed naturally over time. The presence of those breakers changed the depositional patterns along that beach. So when I was a kid, those sandbars were a lot smaller and thinner, you could still get out to the breakers but they were much narrower. They have expanded over the years and created these large pools.
Nedret Andre: That kind of makes sense, were we at a tidal pool area for the restoration?
Phil Colarusso: Yes, at high tide the sand bars are covered. But there is plenty of water exchange. Those sandbars and breakers provide some protection against storms, where the natural meadow is growing. If you go to the furthest breaker of the Five Sisters, the one that is closest to Revere, not the one closest to Boston (where we were). There is a beautiful, small meadow inshore of the fifth breaker. It is really lush green meadow with dense shoot density is really high.
There are five of those breakers, we were working between the first and the second breaker. Where we were transplanting, If you went to the fifth breaker you would find this natural seagrass meadow. It is technically further North, we were working more south end.
Just based on how the sand bars have developed and the direction of the storms this little pocket inside of the breaker is the perfect spot for transplanting eelgrass.
Nedret Andre: Would you say it’s a man-made or human-made natural estuary, what would you call that?
Phil Colarusso: It’s man-altered for sure, that natural meadow that is there in near the Fifth breaker only arrived there on 2012.
So it has not always been there. If I had to guess, Winthrop is opposite Nahant, where there is always been a lot of eelgrass. It’s possible some seeds from Nahant made their way to Winthrop and took hold near that Fifth breaker.
Nedret Andre: That is great news that a surprise meadow can just appear!
Phil Colarusso: Yes, it is one of the most positive stories of seagrass recently we will have DNA data on their genetics
Piping Plovers, Terns, and Oystercatchers
Nedret Andre: I noticed several sections of the beach were fenced off. Are they protected for nesting birds?
Phil Colarusso: Yes, So this time of year, the beach is blocked off for Piping Plovers, Terns, and Oyster Catchers who are all nesting on the Winthrop Beach. In fact, Piping Plovers are Federally endangered. In fact Winthrop Beach and Revere Beach have the highest success with hatch rates for Piping plovers. It’s pretty odd since they are both pretty urban beaches compared with beaches like Cranes Beach in Ipswich and Cape Cod. They have long sandy beaches with smaller human populations and also have Piping Plovers. But the success rate for hatching is much less. People who are birders theorize that those areas are more natural and have more natural predators for their nests. In Winthrop and Revere there are more people, so it reduces raccoons, skunks, and fox, some of the natural predators for the nests.
Nedret Andre: Has the beach itself changed since you were growing up?
Phil Colarusso: It has changed considerably. About ten years ago, the Commonwealth rebuilt and elevated large sections of the beach for coastal protection. That altered the beach’s slope and texture and added more sand. Vegetation now grows along the upper beach, creating nesting habitat for birds I did not see there as a child. Human alterations can have complicated consequences, but in this case some of the changes also created new habitat.
Nedret Andre: It’s fascinating to think that man-made stuff can bring ecosystems back- even though we always hear about how we are losing so much due to human intervention?
Phil Colarusso: Yes! Humans have the ability to make positive changes for the environment. There are numerous examples of restoration efforts across the planet that are success stories.
Growing Up Along Winthrop Beach
Nedret Andre: What do you remember most about the beach from your childhood?
Phil Colarusso: My mother took me to the beach nearly every summer afternoon. Our section was rocky and usually quiet, so I could turn over rocks, look for crabs, and explore the tide pools. Those days helped set my direction. I had wanted to become a marine biologist since I was about six years old.
Nedret Andre: You were fourteen during the Blizzard of 1978. What happened in your neighborhood?
Phil Colarusso: We lived one block from the ocean. During the storm, the water came down our street and surrounded the entire block. Firefighters evacuated people by boat, but our apartment was on the third floor and my parents decided to stay. We spent about a week without heat or electricity.
Phil Colarusso: After the storm, one of my jobs was to chip ice away from the storm drains to allow the water to drain and subside. Almost everyone else had evacuated, so the street felt eerie. Lobsters and other marine life had washed into the neighborhood. At fourteen I experienced it as an adventure, although it was clearly a destructive event.
Nedret Andre: Did experiences like that influence your decision to study marine life?
Phil Colarusso: They certainly added to my curiosity. I also remember a whale washing onto the beach when I was in middle school. My mother took me out of school because she thought I would learn more by seeing it. I had never been so close to an animal that large. I remember wondering why it had died. I would much rather see whales alive on a whale watch, but the experience made a lasting impression.
Winthrop in a Changing Climate
Nedret Andre: What could rising seas mean, in practical terms, for people living in Winthrop?
Phil Colarusso: Most of Winthrop is at or only slightly above sea level, so the community is vulnerable to flooding and sea-level rise. The beach reconstruction has helped, but the projections I have seen still give me concern. Models contain uncertainty, yet they consistently suggest that large coastal areas will face much more frequent flooding and that protecting or adapting communities will require major investment. In some places, retreat may eventually be unavoidable.
Nedret Andre: What about the future of coastal communities?
Phil Colarusso: Large sections of the coast of the North Eastern United States will have to just be abandoned because they will be uninhabitable due to sea level rise. Already there are homes in Plum Island, Nantucket, and on the Cape, that have fallen into the water or are about to fall into the water. Right now it’s only a handful but the number is going to get larger.
Nedret Andre: I recently went swimming in Plum Island, at the Parker River National Preserve. On my way out of the preserve I saw a new building that had been eradicated in an isolated spot near the marshes. They looked like they were very prepared for rising waters, they had built the whole structure on huge structural stilts. However there is only one road in and one road out, it was hard to imagine how they would leave?
Phil Colarusso: Yes it will be underwater, it is inevitable that Plum Island will be under water, I don’t know the time line..
Note: Check out link WBUR here:
Nedret Andre: How are warming water and sea-level rise affecting eelgrass?
Phil Colarusso: Temperature is an important concern, especially near the shallow edges of meadows. But it is not the only pressure. Light, water quality, sediment, storms, grazing animals, and invasive species can all interact. Sometimes a meadow retreats even when the usual physical conditions appear suitable, and that forces us to look more closely at biological pressures.
An Unexpected Threat: Canada Geese
Nedret Andre: You mentioned Canada geese as another concern. How can they affect eelgrass?
Phil Colarusso: Canada geese feed on eelgrass, and heavy grazing can damage shallow meadows. I recently visited Cobscook Bay in Maine with the Passamaquoddy Tribe. There used to be healthy eelgrass meadows there. I went snorkeling to check it out. The water clarity, temperature, and sediment appeared suitable, yet eelgrass was difficult to find and a large flock of geese was present. Green crabs may also be involved, so the likely explanation could be grazing, crab disturbance, or a combination of pressures. There is another eelgrass meadow in Nahant where the meadow is changing.
Nedret Andre: Yes, I remember being out to Nahant with you and the team a few years ago. What’s going on there?
Phil Colarusso: The shallow edge of the meadow retreated significantly over several years in Nahant. Geese and other animals commonly feed there. The dense meadow begins just beyond the depth that a goose can easily reach at low tide. More recently, I have seen seedlings and patches returning inshore, so I hope that section is beginning to recover.
Nedret Andre: Do you think this might be occurring elsewhere?
Phil Colarusso: It’s happened in parts of NH – these shallow meadows are at risk now. This is what geese naturally do- look for food. We have so many Canadian Geese now that don’t migrate anymore- their system is out of balance. The meadows are basically suffering especially around the shallow edges.
Nedret Andre: Is there something we can do to shoo them away?
Phil Colarusso: Plastic coyotes are put into fields to scare them, maybe we need swimming coyotes
How the Winthrop Experiment Works
Nedret Andre: How did the team transplant adult eelgrass shoots?
Phil Colarusso: We used circular burlap discs that we sometimes call ‘tortillas.’ Ten eelgrass shoots were woven into each disc. Divers secured the discs to the bottom, usually burying them slightly and adding rocks to keep them in place.
.Nedret Andre: What were the hula hoops used for?
Phil Colarusso: They marked planting areas with two different starting densities. The lower-density plots received three burlap discs, or thirty shoots. The higher-density plots received eight discs, or eighty shoots. By comparing the plots, we can ask whether initial density affects survival and how quickly the transplants expand.
Nedret Andre: Are green crabs a threat to the new plants?
Phil Colarusso: Green crabs are present almost everywhere, including natural meadows. They can cut and disturb eelgrass, but once a meadow reaches sufficient density, their impact may be less severe. We hope the Winthrop transplants will eventually coalesce into a thicker, more resilient meadow.
Nedret Andre: How will you measure whether the restoration succeeds?
Phil Colarusso: Researchers from Northeastern University are counting shoots monthly. The transplants have already survived two significant storms, and survival so far appears encouraging. Monitoring will continue through the fall. The team also plans to add seeds near the established adult shoots, testing the idea that seedlings may perform better when adults are already present.
Nedret Andre: Yes I recognized some amazing Doctors of seagrass at the restoration site including Randall Hughes and Alyssa Novack, what a treat!
Phil Colarusso: Yes, I know it’s a great group including Forest Schenck and Tay Evans who are also a part of effort as well. There is a lot of good thinkers and minds with this group. There also a lot of practitioners who will take what is learned and implement it elsewhere.
Blue Crabs as a Sign of Warming Water
Nedret Andre: Blue crabs have been appearing farther north. What can their presence tell us?
Phil Colarusso: Blue crabs have expanded northward and are now observed in Massachusetts waters. They depend more heavily on seagrass habitat than green crabs do, so eelgrass functions almost like an apartment building for them. Recording where blue crabs occur and whether they are reproducing can help us understand changing water temperatures. I understand they have been observed as far north as southern Maine and are breeding on Cape Ann
Seeds, Rhizomes, and Resilience
.Nedret Andre: Why are restoration programs increasingly interested in seeds?
Phil Colarusso: Working with seeds can be logistically easier and less expensive than transplanting adult shoots, particularly at a large scale. Adult-shoot projects are constrained by the time and labor required to harvest, prepare, and install each transplant. Large-scale seeding can cover a much larger area, although it may take repeated attempts before a site becomes established.
Nedret Andre: What is the difference between a meadow spreading by rhizomes and spreading through seeds?
Phil Colarusso: When eelgrass spreads through a rhizome, it sends out daughter shoots that are genetically identical to the original plant. This increases coverage, but it does not add genetic diversity. Rhizome expansion is relatively slow – approximately 1 meter per year under suitable conditions.
Listening to Phil describe these two forms of seagrass growth enriched how I pictured the meadow. One process creates genetically new plants; the other slowly extends an existing organism across the ocean floor. These intertwined forms of reproduction have informed my recent paintings of seedlings, rhizomes, and submerged coastal networks. The painting above called “Rhizomes I-III” depicts this lateral movement that Phil was explaining.
Phil Colarusso: Seeds are produced through sexual reproduction. A meadow can produce enormous numbers of seeds, and even if only a fraction become established seedlings, they can increase coverage over a large area. Seeds also introduce genetic diversity. Greater diversity is generally associated with resilience, so persistent meadows probably need a combination of lateral rhizome growth and successful seed production.
My painting “Seagrass Seedlings” explores new seedlings in the spring as they take hold in soft shifting earth. I created various bulbs shapes from imagination thinking about all the amazing components of coming together to create the perfect conditions for a seagrass meadow to take hold. I was trying to capture the sense of hope and renewal.
Could Winthrop Become a Model for Future Projects?
Nedret Andre: What makes the Winthrop project especially valuable?
Phil Colarusso: It will be carefully monitored. Too often, projects that do not succeed are not studied closely enough to explain why. Even successful projects may not identify the variables that mattered most. At Winthrop, we will have survival counts, density comparisons, environmental monitoring, and observations from a strong group of scientists and practitioners. What we learn can inform other projects.
Nedret Andre: What do you hope Massachusetts eelgrass will look like in 2040?
Phil Colarusso: My hope is that we can create something like the restoration community that developed in Virginia: not just a few academics, but a larger network of scientists, conservation organizations, practitioners, and volunteers committed to large-scale seeding. A project may not take on the first, second, or even third attempt. We need to be persistent, learn from each effort, and bring many more people into the work.
Tail End, was painted this summer after my trip to Winthrop with these amazing scientists. It is an abstract pool surrounded by unusual man-made rock, an invented Jetty of sorts. The seagrass melds into its new home establishing its roots, as we get a flicker of something that just swam back into the water. Maybe a fish, or a goose, or a blue crab?
Thank you, Phil for this thoughtful interview following my morning with the team in Winthrop. Our conversation brought into focus the patience, experimentation, and collaboration behind seagrass restoration.
Thank you also to Alyssa Novak, Randall Hughes, and the whole team for welcoming me into this work. Seeing this work and care first hand deepens my connection to the seagrass habitats I paint and the people restoring them.
How to Get Involved
Phil recommends connecting with local organizations already conducting restoration and monitoring. Salem Sound Coastwatch and the North and South Rivers Watershed Association participate in seagrass work through the MassBays program and provide useful starting points for volunteers. Here are live links to explore and donate to:
Center for Coastal Studies Ptown
Massachusetts Bays National Estuary Partnership
North and South Rivers Watershed Association
