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Seagrass Decline in Moreton Bay: What Long-Term Research Reveals About Ocean Change · How To Protect The Ocean

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I want you to imagine you're diving into a shallow bay where your fin
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stir up a lush green carpet beneath you, a carpet that hides sea turtles,
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juvenile fish, and secrets of the sea.
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Now imagine that carpet shrinking, thinning, and changing color
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vanishing patch by patch.
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That's what scientists are seeing today in Moreton Bay, Australia, and it's a warning
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for every coast, including our own.
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We're gonna be discussing the disappearing Seagrass Meadows over a decadal, or
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more than a decade study of this area and why we need to protect it as well
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as other seagrasses around the world.
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On this episode of the How to Protect the Ocean Podcast, let's start the show.
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Hey everybody.
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Welcome back to another exciting episode of the How to Protect the Ocean Podcast.
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I'm your host, Andrew Lewin, and this is the podcast where you find
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out what's happening with the ocean, how you can speak up for the ocean,
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and what you can do to live for a better ocean by taking action.
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And I'm telling you right now, this is a special episode.
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It's special for a number of reasons.
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One.
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I'm discussing a habitat that I really, really enjoy.
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It's called the Seagrass Meadow.
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Seagrasses are extremely important.
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We're gonna get into it, why they're so important today, but today is
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very special because I have been wanting to do this for a long time.
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I would like to kick off the project called the Seagrass Effect.
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It is going to be a Seagrass podcast that's gonna share research, conservation
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and restoration news from around the world about seagrasses on a podcast.
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Its very own seagrass podcast called The Seagrass Effect.
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It's going to be part of the Speak Up for Blue Podcast Network, and I am
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doing a crowdfunding for this podcast, the Seagrass Effect on a crowdfunding
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site, a new crowdfunding site specific
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for Ocean Projects called balean.org.
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You may have seen me interview the founders, Sanders and Bart
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Oor on this podcast at some point in time over the summer.
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I did it twice, actually.
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Talked about collaboration.
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Now we are capitalizing.
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They have launched a site, balean.org.
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They have launched a number of projects including mine, where I'm
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trying to raise money to launch this podcast, and I'm trying to do it
2:09
for the new year, and what you can do is you can donate your
2:13
money to get this podcast going.
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And the reason I'm doing this is because I want this to be your
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podcast, not just my podcast.
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I want this to be your podcast.
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This is a podcast where we're gonna find out what's happening with seagrasses.
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We're gonna find out what research is going on.
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We're gonna find out about the restoration efforts that are
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happening around the world, and of course, the conservation efforts
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that are happening around the world.
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It's going to be awesome.
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We're gonna hear from people all over the world.
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I can't wait for it.
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So if you wanna donate and get this thing going, you can go to
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speak up for blue.com/seagrass.
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It'll take you right to my Balean page for my project.
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You can donate right there.
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You can also donate to Balean to support their work in all the
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other projects that they're doing.
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Check it out.
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That's speak up for blue.com/.
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Sea grass.
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Now you're wondering, Andrew, why seagrass?
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Why not coral reefs?
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Why not the deep sea?
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There's so many other ways we can do.
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It's because we don't know a lot about seagrasses and it's not really
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a thing that we discuss every day.
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You see on beautiful documentaries of coral reefs, it is wonderful to see.
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But the sea grasses, they kind of have a bum wrap.
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They are green, they are lush and they handle a lot of biodiversity, but we just
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don't really understand how important they are to coastal ecosystems, how important
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they are to fisheries, how important they are to protecting our coastline.
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Now I've been talking about it on this podcast for a long time, but when you
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dive or go snorkeling on a seagrass meadow, you never know what to expect.
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You really don't.
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It is phenomenal to see.
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Case in point, I was snorkeling with my brother.
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We were going out, we were in the Grand Cayman.
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We were on a family trip.
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My brother and I decided to go around the corner, around the
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coast corner, catch a wave.
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Like catch a current and come back around into this massive bay.
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So we go, we get a drive, we go to this corner, we hit a
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bunch of rocks, we go diving in.
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We have snorkels, we have a mask, we have a buoy just in
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case we get lost, God forbid.
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And we don't really know exactly what we're doing or where we're going,
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but we're told this current will just kind of take us into this bay.
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So we follow the current and we see, you know, like little sharks.
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As old, my brother said he saw a massive shark, but it's a
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little four foot nurse shark.
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We see a bunch of fish, we see a number of different corals, and we see these rock
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scapes and sea turtles and everything.
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It is wonderful.
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We start to come in closer to the bay.
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Now, there was a bit of a current that took us in, but it wasn't
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taking us right into the bay.
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So we had to kick, kick, kick as much as possible to get into the bay.
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But once we did, we got into very shallow water.
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We're probably looking at about maybe four feet, three to four feet, and my
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brother and I are just kind of going over and we're going over a sea grass meadow.
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And as we're going over this seagrass meadow, we start to see this movement
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of all these fish and all these little invertebrates, these little shrimp
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that are in the seagrass meadow.
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They're hiding in the blades of these plants, of these
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specialized aquatic plants.
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And they're starting to like move away from us as we kind of
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come across and then we see it.
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We see this massive stingray just hovering right above the seagrass meadow.
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It was incredible.
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So incredible that I went, holy cow.
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Like yelled it out into my snorkel.
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So more sound like, holy cow.
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It was awesome.
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We enjoyed it.
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We talked about it forever.
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And once we got to shore, we had a couple beers and we were talking about how cool
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and how lick the size of that stingray.
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And my brother, who is not a marine biologist, who doesn't
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snorkel or doesn't screw.
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Couldn't believe how much life was in these seagrasses, and this
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is why they are so important.
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One of the reasons why they are so important.
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They provide so much biodiversity and so much protection for juvenile fish.
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These little larva and growing larvae of invertebrates is just the amount of
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biodiversity sometimes, and oftentimes outweighs and outperforms and out
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produces the biodiversity of coral reefs and this is why it's so important.
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We just don't know about it.
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'cause we don't talk about it a lot.
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And there are a lot of researchers out there that are talking about a
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project seagrass, a numbers, a network of researchers that are doing in
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Europe and along the coastlines in North America and all over the world.
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And so we need to talk more about it.
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But today we're gonna be focusing on Moreton Bay in Australia because there
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was this long-term study, 19 years I believe was the study and it was
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absolutely phenomenal in this study.
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It was a study that was able to document a long-term decline.
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I know you're like, Andrew, why are you getting so excited about this?
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A long-term decline in a number of different indicators, I guess is what
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you'd call it, a number of different indicators of seagrass health.
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And the difference here is that the long-term study shows this long-term
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decline, but there are a lot of short-term studies that happen.
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We'll talk about that in a little bit that don't show this long-term decline, and
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that is where we lose the pieces of how healthy a Seagrass meadow actually is.
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But first, before we get into that, I wanted to talk a
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little bit about Moreton Bay.
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'cause Moreton Bay is a special area.
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And I've got some stuff that was written, I did a little research
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here that I have to remember.
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there was a lot of stuff to talk about, but essentially it's a large,
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shallow, semi enclosed coastal embankment in Australia, located in
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southeastern Queensland, Australia, adjacent to the city of Brisbane.
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So Brisbane, we know Brisbane.
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It's a coastline town on the east coast of Australia, it's on the Barrier Reef.
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It's just beautiful.
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The Moreton Bay stretches roughly about 125 kilometers from Kundra in the north
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to the Gold Coast in the South, covering an area above 1500 square kilometers.
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The bay is shielded from the Coral sea by a chain of long sandy
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barrier islands, Moreton Island,
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North Strat, broke Island and South Strat, broke Island, which create
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calm, protected waters inside.
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This is where the meadows, these sea grass meadows could actually, basically
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live and thrive in these areas.
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Now, the base depth average is around 10 meters, making it an ideal
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environment for seagrass meadows, mangroves, and tidal flats, which
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together form one of Australia's most productive coastal ecosystems.
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These habitats support an incredible diversity of life.
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Dugongs, green sea turtles, dolphins, migratory shorebirds, and
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hundreds of fish species, depending on the bay's rich food webs.
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Now several rivers, including the Brisbane, Logan and Pine Rivers flow
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into Moreton Bay carrying sediments and nutrients from the surrounding catchments.
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The mix of freshwater and seawater creates gradients of salinity and turbidity that
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influence the distribution of marine vegetation such as sea grass, however.
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The same river inflows can also bring pollutants and sediments from urban
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and agricultural areas, threatening the Bay's water quality, which we're
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gonna get into in just a little bit.
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Moreton Bay is part of Moreton Bay Park, established in 1993
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to protect its ecological, cultural and recreational values.
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The park encompasses both protected zones and areas open to sustainable
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fishing, boating, and tourism.
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This looks like a multi management system, just like the Great Barrier Reef.
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Obviously not in the same size.
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In addition to its ecological importance, the Bay holds deep cultural significance
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to the Quandamooka people, the traditional custodians of the region
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who have maintained connections to these waters for thousands of years through
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fishing ceremony and stewardship.
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Today, Moreton Bay is a living laboratory where scientists study
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coastal change, habitat restoration and the effects of climate and
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human activity on marine ecosystems.
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It represents both a biodiversity hotspot and a warning system showing
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how quickly coastal environments can change when pressures like development,
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pollution, and extreme weather converge.
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So in this study, decal monitoring shows seagrass decline and community shifts
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following environmental disturbance in Moreton Bay, Southeastern Queensland.
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Australia is such a long, long, long title.
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The Decadal range covered between 2004 and 2023.
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So there's a long range.
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Now, what's nice about this is no matter what disturbances happen, so we talked
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about earlier I mentioned how there's like storm events or flood events.
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These things have short term effects on a seagrass meadows.
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So if you're looking at short term, you can see that the seagrass meadows is
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probably ruined or uprooted in some areas.
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May shrink in size after a flood or after some sort of major storm event.
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But it quickly, in about one or two years, come back to a normal
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size, but not all the time.
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Sometimes bigger, sometimes smaller, depending on what's happening after that.
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However, when you look at a long-term study 19 years between
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2004 and 2023, you start to see how the patches are getting smaller.
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And what's happening.
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So some of the disturbance events that happened with major flood cyclones
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and water quality fluctuations allowed scientists to evaluate how their
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seagrass Meadows responded and recovered or even failed to recover over time.
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So I thought it was really cool.
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They looked at seagrass extent.
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species of actual seagrasses and resilience to environmental
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disturbances in Moreton Bay, Queensland.
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So that's what they're looking for.
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So what they noticed was that the total seagrass cover declined.
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The overall area of Seagrass Meadows in Eastern Banks of
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Moreton Bay shrunk compared to the early two thousands Baseline.
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The loss was most pronounced after major disturbance events, such
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as extreme rainfall, flooding
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and resulting turbidity which reduce light penetration and smothered sea grass.
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Species diversity and dominance changed.
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There was a decline in species richness.
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So the number of species which sensitive species like Halophila ovalis and Halodule
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uninervis, sorry for my mispronounced of the species names losing ground
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in some areas.
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They lost ground in some areas.
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These were often replaced or out competed by more tolerant, opportunistic species
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that can handle the turbidity and the unstable conditions indicating that a
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shift in community structure happen.
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Now, this is really interesting because when you start to see these
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shifts from like more sensitive to disturbance a species to a more tolerant
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species, this is very similar to what we're seeing happen in a lot of
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coral reef areas.
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A lot of the corals, like the branching corals are a little bit more sensitive
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to temperature change or pH change.
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We're starting to see them functionally extinct in certain
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areas like Key West, which is very disturbing, and to even see that.
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It's not something we wanna see.
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It's the precursor to like actual extinction in specific areas, but we're
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seeing a more tolerant species stay around like the softer corals that can
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handle these different types of species, which was predicted a long, long time ago
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when we start to look at how climate change was gonna affect coral reefs.
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It is kind of interesting to see that it's the same thing happening with a
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lot of different species, especially in these important, important habitats.
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Now, we also saw change in habitat quality and density that decrease.
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So seagrass biomass and chute density.
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So the chutes are like underneath, fell in several monitoring zones, meaning less
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habitat, complexity for marine life such as turtles, dugongs, and fish nurseries.
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And then of course, these declines reduce the bay's blue carbon capacity.
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Now these seagrass meadows have the ability to sequester carbon.
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That means they can keep carbon inside, not only their aquatic
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plants, but also in the root system, which is really interesting.
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So the fact that they lose that the ability, it's the ability to score
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carbon and the ecosystem resilience of having a diverse and more complex system
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of Seagrass Meadows.
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It'll actually lead to further environmental change down the road.
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So, in short, the study documented decrease in seagrass area species
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diversity and structural health with long-term implications for
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biodiversity, carbon storage, and coastal ecosystem stability.
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That is essentially what the study covered . This is something that
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is not good when we look at how we monitor and manage these areas.
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Now, the monitoring is important.
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Having this long-term study where short-term studies can see quick
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recovery after storms or flooding doesn't necessarily mean that it's going
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better.
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What they notice is that the patches kept getting smaller and smaller
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over the years, but when you see like a patch get really, really small
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and then grow back, you're like, oh, it actually did really well.
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Within a year or two, it started to come back.
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That means it must be coming back.
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But when you look at the 19 year data set and you start to see
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these patches over time getting smaller and smaller, even though the
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fluctuation kind of goes, it shrinks and then grows and shrinks and grows.
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It's growing smaller and smaller.
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It doesn't have the time to recover.
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I assume what would happen if it's in a healthy state and these storms come
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in, they break down maybe a specific habitat, shrink it in its size and maybe
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even species diversity or even just size.
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Having that species diversity still there can allow it to grow back to its
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original size if it's given the time.
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But the frequency of those storms, the frequency of those flood events, the
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frequency of those disturbances with other cumulative effects like increased
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nutrients or sediment that can actually smother these plants is not going to help
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when we're looking at long-term data sets or long-term health of the seagrasses.
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So that's something that needs to improve.
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So here's what the study authors kind of said between the two things.
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Obviously we need more decadal study, we need more long-term data
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sets and continued monitoring.
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That's something that's really big.
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So that's something that really needs to help.
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So we need to improve water quality.
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The study identified turbidity and nutrient runoff, especially
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from catchments that are key drivers to sea grass decline.
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Looking at sediments and nutrient loads entering Moreton Bay by improving
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catchment manages, especially around the Brisbane and Logan Rivers.
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So those are two rivers that cause the most damage.
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Actions include strengthening the erosion control or on
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agricultural and construction lands.
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That'll be really important.
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Upgrading stormwater and wastewater treatment infrastructure.
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Restoring riparian vegetation and filter runoff before it
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enters the coastal waters.
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All three of these things can be done.
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That's the good news.
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All three of these things can be done if the political will and the money is
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there to help these seagrass meadows.
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That can be done.
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That's not difficult to do.
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That's been done before, and it can be done again.
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So don't let people tell you that it can't be done, that
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this restoration or protection, long-term protection can be done.
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You can also maintain and expand long-term monitoring.
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That's something that's gonna be really good.
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Monitoring costs money.
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Now you can use like remote sensing.
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You can use drone footage.
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You can use just regular monitoring, quadrat studies and
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so forth, quadrat monitoring.
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And that can be done by students and by academic institutions
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and by nonprofit organizations.
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These things are not quite expensive, although the resources are expensive.
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Obviously drones are expensive.
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Satellite imagery can be costly if it's not freely available.
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But you can actually tell a lot from this.
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But it costs money.
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It costs resources like people and, materials and stuff to actually
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do this kind of monitoring.
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And it can get expensive at time.
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I've seen this before with long-term monitoring studies is that you'll see
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like gaps during those certain years where funding was either taken away
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or at reallocated to something else.
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But as long as you have that long-term data set and you keep
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coming back and allowing it to kind of grow and grow and grow.
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You can get back into a better state with these long-term monitoring data sets.
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You can manage the disturbance impact.
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So Seagrass lost in Moreton Bay was strongly linked to extreme weather events.
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So obviously you can't stop the weather events, floods and storms.
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And of course there are turbidity pulses.
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However, the authors suggest proactive measures to mitigate and manage
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disturbances, such as protecting refuge meadows, so areas that are
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less impacted by runoff or turbidity to allow them to serve as a seed and
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propag resources for the recovery.
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So allow them to be like they're in good shape even during these storm areas.
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So allow them to, you know, like they'll have their seeds and allow
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them to restore the rest of the reef.
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Use that as a source.
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You can implement rapid response plans after major disturbances to assess
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and assist recovery, for instance, by reducing local stressors like
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boat damage or dredging after runoff.
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So let's not put more impact on them after these big stressors.
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Let's put less impact by doing that right after.
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And maybe just short term responses.
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You can protect high quality habitats.
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So we kind of mentioned it earlier before.
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They emphasize protecting remaining healthy seagrass meadows from physical
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disturbances such as anchoring, dredging, and coastal development.
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I've had the project Seagrasses guys, and, team on this podcast a number of times.
17:51
The biggest thing that they said is anchoring.
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So having a buoy system where you can actually, the boats can like
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link up to a buoy system so they don't put their anchors down.
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They can stay in one spot to do whatever they need to do.
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That will be really helpful.
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Let's limit dredging and then of coastal development.
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Of course.
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And then expanding and strengthening marine park zoning in Moreton Bay
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was highlighted as a way to ensure these meadowss remain functional and
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can recolonize degradated areas.
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And then, support active restoration and research.
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That's gonna be very important.
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Restoration is very expensive, so you can support that.
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That would be great.
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So active restoration, such as transplanting sea grass shoots,
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reseeding, and improving substrate stability is always helpful.
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They encourage further research in restoration techniques, light thresholds
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for recovery and the resilience traits of local species to inform
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large scale restoration planning.
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And then finally address climate and cumulative stressors.
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We know what we need to do to do that.
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Let's limit our emissions, include protecting deeper, cooler water meadows,
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and identifying potential migration zones for seagrass as conditions shift.
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So the big thing is reduce local stressors.
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So pollution, turbidity, dredging, sustaining long-term monitoring
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to track trends like we're already doing, protecting and restoring key
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habitats, and integrating climate resilience into coastal management.
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That's what we need to do.
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So we have the problem, we have the area, we have the problem that it's
19:06
facing, and we have the solutions now we need to implement it.
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And what's interesting about this.
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You know, like I said, I love seagrasses.
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I almost did a PhD on Seagrasses.
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but the one thing that's interesting to me about this, and the project that I'm
19:19
putting on for the Seagrass effect is that people who donate to the Seagrass effect,
19:23
we're gonna be taking a portion of that money and we're gonna be helping restore a
19:27
site of seagrasses somewhere in the world.
19:30
And we're gonna just keep going.
19:32
As long as the Seagrass effect is going, we're gonna continue to support
19:35
Seagrass restoration by your donation.
19:38
So, par of the Seagrass donation is not only gonna go to the Seagrass effect,
19:42
the podcast to produce podcasts, to share resources, to share research, to share
19:47
conservation efforts, and to share tactics among scientists who also listen to this.
19:52
'cause one thing that I learned about doing podcasting is that
19:55
researchers will listen to it.
19:56
Early career scientists will listen to it.
19:58
Scientists will listen to the podcast 'cause they wanna find out what
20:00
their colleagues are doing or they wanna find out what somebody in their
20:03
particular area are doing that's different from them or where they can
20:06
collaborate or they can learn from.
20:08
And so just by having this podcast, we are actually into integrating, sharing
20:12
of knowledge for people around the world on a regular basis, once a week basis.
20:17
That's the goal.
20:18
Once a week we release an interview episode.
20:20
That's the goal for this, and I can't wait to bring it to you.
20:23
On top of that, we're gonna help an active seagrass restoration site.
20:27
We're gonna help do that.
20:28
We're gonna come in on the project and we're gonna talk about the increase
20:31
of what we were able to accomplish and what that site is able to do.
20:34
You're gonna be a part of that restoration process.
20:37
It's gonna be a lot of fun.
20:38
I can't wait for you to do it.
20:39
So if you go to speak up for blue.com/.
20:42
Seagrass, so speak up for blue.com/seagrass.
20:46
All one word.
20:46
You can donate to the project that's right now on Balean for
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the Seagrass Effect podcast.
20:52
I can't wait for you to see it.
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I can't wait to do it, to be honest, but I need.
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That initial money to start this project.
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It's expensive, it's time consuming, and I wanna make sure that I do this right.
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So, the Seagrass Effect, speak up for blue.com/seagrass is
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where you can go to donate.
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And of course, if you wanna find out any of the resources,
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just check in the show notes.
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And if you have a question, a comment, love to hear it.
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Let me know in the comments below.
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If you're watching this on YouTube.
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If you're listening to this on your favorite podcast app, you
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can contact me in two ways.
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Instagram dm me at how to protect the Ocean, that's at How to Protect the Ocean.
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Or you can go to speak up for blue.com/contact, fill out the
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form and go right to my email.
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I'll answer you back as soon as possible.
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I wanna thank you so much for not only those of you who are considering donating
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to this project and getting it to start up and supporting conservation research
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for sea grass and restoration, but also for listening to this podcast here
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at How to Protect The Ocean Podcast.
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Thank you so much for listening.
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I'm your host, Andrew Lewin from the True North Strong and Free.
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Have a great day.
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We'll talk to you next time and happy conservation.