Seaweed City

Jake Stavis:

How did you fall into seaweed?

Shanjana Mahmud:

I was interested in aquaculture—I didn’t grow up on the water so it seemed like this strange, very whimsical dream. I started learning to grow oysters in the North Fork of Long Island. I ended up working for an oyster farmer who was trying kelp farming. Luke started coming with me to work on the farm. We both worked along NewtownCreek, and we were just thinking about how seaweeds could benefit those waters.

Luke Eddins:

The big idea with growing seaweed in Long Island is that it’s good for the bays. In NYC, we have all this water that is super polluted so we just thought, how might that benefit this environment?

SM:

But our backgrounds are in the arts. I work as a scenic artist in the film and TV industry.

LE:

I’m a technical designer—I mostly build stuff for film and events.

JS:

Has your design background informed your approach to seaweed farming?

LE:

Definitely. There are fairly established strategies for more rural areas, but growing seaweed in an urban environment requires different tactics—it’s attractive to try to figure that out.

SM:

Each location in Newtown Creek required problem solving in terms of installation, mounting and anchoring systems. We think about designing for bulkheads, or using pre-existing pilings and the pier structure. It’s not like we’re following the best practices for a farmer who’s like trying to maximize their crop for sale.

LE:

But we do like it when we maximize our crop.

JS:

That’s a good segue into site selection. During my tour of Newtown I saw two of the growing sites. Do we consider the waste in the water to be nutrients?

LE:

Absolutely. We were already spending a lot of time there, and it was an area we wanted to improve. But the creek also has a lot of challenges that don’t make it ideal for kelp farming in many ways. The Newtown Creek Alliance and LaGuardia Community College professor Dr. Sarah Durand were instrumental to our work there. They’ve been stewarding Newtown Creek for nearly two decades.

JS:

How did you end up at Governor’s Island then?

SM:

There was a call for projects from small businesses and nonprofits to try out water-based pilots through the Trust for Governor’s Island—it’s called Living Lab. We were selected for their inaugural year.

LE:

For any site it really helps to have community and institutional support—you can’t just show up somewhere and do it. The Trust for Governor’s Island gave us some money, space, and permission to do it in the water. Without any of that, it couldn’t have happened there. 

JS:

You both talk about cultivating a community—what do you hope this will grow into?

SM:

Our goal is to create seaweed gardens all around New York City, working with community-based organizations to run programming, design, maintenance, data collection, and end usage. We have organizations who have given us letters of support in Queens and along the Hudson. We have a group along the Bronx River that’s interested. Our five year vision is to have these installations, with a local boat house or similar organization collaborating in the planting, installation and maintenance. 

LE:

Seaweed cultivation is great because it gives you a window into what’s going on under the surface of the water. There’s this whole world under there but in New York City, people don’t really think about it.

JS:

When we were on the creek, you talked a lot about creating living shorelines. You already mentioned oysters, but does your kelp cultivation support other species that we should be aware of?

SM:

We’re taking care of NYC’s intertidal zone. Our seaweeds are not near any oysters unless they’re wild, but one critical species in Newtown Creek is ridged mussels. They are really great with filtering water…

LE:

…Down to the level of viruses—they can filter extremely small stuff. A lot of small animals live in the kelp, so it provides the basis for a food web—shrimp and isopods that fish eat, and then birds that eat the fish—it’s fundamental for this whole gradient.

JS:

I think of seaweed primarily for its culinary use—these crops aren’t fit for human consumption, but is anything eating the seaweed and is that something we want?

LE:

We like to see animals eating the seaweed, unless it’s geese and they eat all of it. In that case we try to hide it from them.

SM:

Our seaweeds are three feet below the surface, so it’s not the easiest for some birds, but definitely lots of crabs are consuming the seaweed.

JS:

What can be done with the harvested crop?

SM:

It really depends where it’s coming from. Off of Governor’s Island, there’s ocean water coming in twice a day, so the water doesn’t have the heavy metals we encounter in Newtown. We can turn that seaweed into soil amendment, basically by drying it and cutting it up in little pieces.

LE:

We’re distributing some soil to organizations on Governor’s Island like Earth Matter. We’re also going to give it away to interested people to raise awareness about what we’re doing. The big idea there is taking excess nutrients from the water and putting them back into the soil. It mainly benefits the microbiome. It’s called a “biostimulant.”

SM:

With the Newtown seaweed, we’re drying it and setting it aside. We’re not sure where it’s going to go.

LE:

But some promising avenues are opening up, suggesting how we could use it safely without spreading the toxic waste.

SM:

There are people who use seaweeds to make bioleather.

LE:

Or plastic replacements, which are potentially really great. A lot of other bioplastics are made from corn, which takes a whole lot of fossil fuel to grow.

SM:

Seaweed basically needs the nutrients in the water and photosynthesis.

JS:

I saw on your Instagram photos from a nursery—can you tell me more about that?

SM:

We started the nursery last fall. We collect harbor water and sterilize it. We work with divers who visit the few wild beds of sugar kelp in Montauk, where they collect reproductive tissue. In the nursery we create the conditions for these eggs and sperm to fertilize on tiny strings. 

LE:

These strings are coiled around PVC pipes. We feed them and give them light for a month and a half, over which the seaweeds grow a few millimeters. At that point they’re long enough to go out into the harbor.

JS:

This seems very exacting and sensitive. There’s of course a longer history of seaweed cultivation in the region, including indigenous traditions. Without nurseries, how else can one get kelp out on the lines?

LE:

Well before we had the nursery, we would purchase the spools from someone else, but growing seaweed on lines along the east coast is a relatively new method. It’s really only become popular in the past 10 to 15 years. You can also use rafts. A really simple method is just collecting small pieces of seaweed and then tying them to a rope to propagate them. 

SM:

Some species are more conducive to that than others.

JS:

How is the warming of the water impacting your work?

LE:

Sugar kelp grows in the winter and it dies when the water gets too warm. We’re pretty much at the southernmost tip of its range, and that’s just going to shift northward.

SM:

Woods Hole Oceanographic Institute [in Massachusetts) has been isolating strands of sugar kelp that can do better specifically with warm waters. 

LE:

But there’s also so many other seaweeds.

JS:

I saw you’re also working with sea lettuce. Is that good for warm water?

SM:

Yes, you see that a lot in Jamaica Bay and Plum Beach.

JS:

What has surprised you the most in your experiments?

LE:

I think the biggest surprise was just that seaweed could grow at all in Newtown Creek. It was a big gamble. A lot of the people we talked to in the seaweed world thought it wasn’t going to happen. 

SM:

Seaweed City as an organization is kind of a surprise. I would say it’s like the way I approach anything as an artist—let’s just try it and do whatever we have to. And then before we knew it, we’re sending this huge folder of documents and permit applications to the city.

JS:

I’m glad to see your art triumph over red tape. How can people get involved in Seaweed City?

LE:

If you have an idea related to what we’re doing, pitch that and then do it. Take it on. There’s so many angles that we are interested in about seaweed but we can’t pursue them all. And surely there are lots of things we haven’t even thought of. We would love it if people would just say, I’m interested in this aspect,”—like trying to push bioplastic or looking at biodiversity on the seaweed lines—just take that and run with it.

SM:

Or someone using mushrooms to digest the seaweed from Newtown Creek because it might have heavy metals or other toxins. I would love for this to have happened already but we don’t have the capacity.

JS:

So, it’s an open call for anyone interested in heavy metal-laden seaweed.

SM:

Yeah. Exactly.