How To Protect The Ocean
SUFB 107: Seagrass Species Uses Alternative Reproduction Methods
A Seagrass species located in Shark Bay, Western Australia is using an alternative reproductive strategy to colonize an area that is highly saline and not normally optimal for the species. In this episode, we discuss why that is happening and what the seagrass species prefers.
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Well, come to the speaker for blue podcast session 107. Hey everybody. Welcome back Today we're gonna be talking about something different. We haven't really talked about in a while We've been focusing on specific species of animals that we love in our their iconic But today we're gonna talk about seagrasses. I'm putting one specific species of seagrass But how that helps shape a habitat and how important they are to to species so they're in the news today That's what we're gonna talk about so stay tuned for this. This is a really good episode I really like this one on the speaker for blue podcast stay tuned Welcome to the speaker for blue podcast helping you get involved in ocean conservation And now here's your host he still puts his hands in the air because he doesn't care Andrew Luan Hey everybody welcome back to another exciting episode of the speak up from blue podcast your voice for the ocean I am your host Andrew Luan founder speak up for blue calm marine ecologist and self-proclaimed Ocean pernour and today on the show we're gonna be talking about Seagrasses one of actually my favorite subjects because I'm a big fan of habitats talking about habitats And I know a lot of people out there like oh, you know seagrasses are not they're like just plants. They're not very exciting They don't really do much. Well, they actually do quite a bit We're gonna talk a lot about what they do and why they're in the news for a special sort of What they call a last ditch reproductive strategy, so it's gonna be kind of cool to talk about something Other than an iconic species. I find this iconic species because it plays such a a valuable role in Sort of tropical areas or even actually every area depending on the seagrass, but how it plays a role in fish development life histories invertebrates all types of animals even even mammals as well as we're gonna talk about today so before we get to the show just want to say thank you to our supporters Ron and Judy dr. Judith Weiss and Claire and Chris jefford. Thank you very much for supporting our campaign on patreon allowing us to continue Professing or getting reaching people with our conservation message our ocean conservation message And if you're the first time listening to this podcast, this is what we do We I have got a nice little team and we work our butts off to get The message that you can live for a better ocean. Excuse me You can live for a better ocean Through changing your daily life Just by little little things and just by making yourself aware of what's going on in the ocean And that's what a lot what we do on this podcast is we let people know what's going on in the ocean, you know recent news We talk about specific species on species Tuesday. We talk we talk to somebody who's working in ocean conservation on interview Wednesdays Thursdays we talk its research Thursday, so we talk about the the latest research that's going on or something and I find that's important A lot of times has to do with the theme of the of the week Which to this week will probably be sea grasses and then you know, it goes on and on so on Fridays We have ocean talk Friday where Nathan Johnson Shows up and he comes up and tell you know We talk about all the different stories that happen throughout the week's extra stories So it's almost like an extra show and it's just a fun time And it's it's a great way to listen to ocean conservation messages What's happening around the world and really inform yourself so that you can make better decisions? Make more decisions for to live for a better ocean. That's that's what we do here So the people who that I just named who are Contributing to that message. We really want to thank you. It's a lot. They're helping you get aware and live for a better ocean So thank you very much for that. So anyway, let's get on to the show. There's on on fizz.org, which is a physiology site We or actually I think it's physiology. I think it's just physics but what we're talking about we're talking about seagrasses and It's in the ecology section. It was actually on February 4th. So last week. I found this story It was supposed to be on we were supposed to talk about on ocean talk Friday But didn't make the cut just last minute because we had other stories to talk about However, I want to talk about today because I think it's so important. I like seagrasses I almost did a PhD in seagrasses. I think they're great. They're great because one they provide habitats So what seagrasses normally do is they just like plants land plants. Well, one they live in the ocean two They're flowering plants three. They actually bring Sediment together. They actually compact sediment and make it sturdy so that it so that the ocean currents don't move it around It doesn't change the landscape So what it does is actually provides a little bit of a safe haven It decreases the wave energy and behind it can cause a lot of just nice gentle gentle waves or currents and and it becomes very pristine Or just becomes very calm and it just allows things to develop allows small fish small invertebrates to just lay back in there Protects wave energy from eroding the the land around there and moving things around and it's just it's just a great way to do that from a physical point So it protects the coastline, which is a big thing it provides protection of little Animals would it be fish or invertebrates from predators because they can hide within the seagrass bed and it's just a wonderful It's just a wonderful landscape. So This is all that I love to talk. I do love to talk about this and it's it's one of those things where seagrasses are I mean They're not highly talked about because there may not be as beautiful as coral reefs with the different colors and the different shapes and things like that But they provide such a functional habitat. They're very similar in in ways of mangroves, right where they provide a functional habitat where they Will provide protection for a lot of species and their their the the seagrasses are very dependent or the species are very dependent on the presence of seagrasses For mortality rates, right? The lower the mortality rates usually are around seagrass beds because they can hide right? So it's always great for that, but today we're gonna talk about one particular species it's post post aden postadonia Australis, which is a species that's found in shark Bay It's one of the more Shark Bay actually before we get into the seagrasses shark Bay is a World Heritage site. I believe yes a World Heritage area in Western Australia It's a it's the most Western point of Australia if you look at it on a map. It's almost like in a W shape I don't know if that's done on purpose or not. I don't think so, but it's Western Australia. You get a big W It's got a lot of seagrasses and seagrasses take up a lot of the Of the actual of the actual area, right? I'm trying to find right here. How much it actually takes up? Just give me one second here Plan seagrasses Seagrasses make up I believe it's like 40% of the actual 4,000 square kilometers of the actual area, which is a very large part of the area and And they're just a bunch of different species There's actually if you go to shark Bay dot org dot AU you can actually find all the information on seagrasses and all the information on on the actual on the actual shark Bay itself, right? And it's just it's just great cuz like you look at the Sedonia Australis, which is the latin name of the species and you'll get the second most common species in the Bay forming mono specific stands So that means it's only it's only that species largely in channels It doesn't like saline waters rarely found in water with a salinity above 50 parts per thousand Which is which are pretty high salinity only has about half the production rate of another different type of species Which is amphibolas Antarctica, which is the one that takes up covering 85% of the seagrass area in shark Bay, so but the interesting part about what's what's been discovered about this species the Poseidonis Australis species is that it has a specific almost like a last ditch reproduction strategy so normally when you think about seagrasses they reproduce in two methods the first is they reproduce vegetatively Which what they do is they have underneath the sand they have these things called rhizomes Which is basically like they're connected roots, so they connect to each Plant that's that that's each stem and it's very similar to the grass in your in your backyard or your front yard And they just kind of grow in stands like that in rows almost and they reproduce that way and it just keeps growing and growing and growing Outwards so that's one of their their their their reproductive strategies The other one is a sexual or production where they grow flowers the flowers have specific features on there that allow for reproduction to occur and then Once they have that like this the seeds they once they have the flowering plants Then they can actually reproduce and it's more genetically diverse And then it can that that plant or whatever comes out of that Will will grow somewhere else and not just within the stand or it'll fall beside it and and and start to grow now Usually that's usually that happens quite a bit as well. Okay, so the fruits containing a single seed In the fun the flower are later dispersed on the water surface floating away and they'll grow elsewhere, right? So there's a researcher dr. St. Clair who is from the University of Western Australia School of Plant Biology and Oceans Institute. She's a senior Researcher senior research fellow Elizabeth St. Clair and her team were examining seagrass metals at Useless loop in Shark Bay. Okay, so it's a specific area in Shark Bay and what they noticed was that the seagrass produced flowers and that produced a fruit Okay, but they were surprised to discover that the flowers did not contain any seeds and the small and that small plants were growing in the place of some flowers and Then what the so that they were like, okay, this is different Usually when you have a flower you don't see a stem coming from that flower and something new coming up So genetic markers. They took genetic Genetic samples or samples. So they did like a genetic generic marker analysis It was able to show that small plants were identical to the seagrass plant So what happens is this the main plant would have these would have the flower would have these stems growing out of the flower They'd be the exact same makeup as The the stem the main stem. So it's the same it's the same Same plant and what would happen is that plant that was growing out of the flower would actually fall beside the plant and it would grow some more This process is known as pseudo Vivipary, okay So it's a reproductive strategy a situation where by normal sexual flowers are replaced by vegetative growth form So like we said before you have flowers, and then you have the the reproductive organs that are in there or the reproductive features that are in the flower and Then you but instead of having the reproductive features you would actually have a stem that would that would come out of there and that stem would break off and then fall beside So the question really remains. Why would a plant? bother to put energy into a flower and fruit production if it didn't help them reproduce through the new seed and Dr. St. Clair theorized that the plant is attempting this reproduction technique in hope that the baby plants will float away and take root elsewhere and You know, she does it this this strategy is very successful a secret, you know as seagrass roots are so the first The first strategy I talked about how they they reproduce through rhizome generation, which is root production but they hope But almost unbelievably sent they are almost unbelievably sensitive to saltwater and none of the other plants have been observed since They separated from their flowering stems So we know that this is what dr. St. Clair's a quote that she says she goes we know that the seagrass meadow is has low genetic diversity and it lives in a stressful environment So both of these factors explain the failure of sexual reproduction. So essentially what's happening is they're living in an area that is highly Sailing so it has a high salt content which is difficult for this plant to live in What I just said before the plant doesn't really like living in areas that are higher than 50 50 50 farts Wow, I can't believe I just said that 50 parts per thousand And so so it becomes difficult. It's like living in It's like for us living in in a situation where there's low oxygen in the air Right, it's very difficult for us to function. So some of our functions in our body may not work as well as others, right? So it's more of a an evolutionary Strategy to just survive and get out. Normally the whole point of sexual reproduction is to get a different types It's to get genetic diversity, right? Because you're getting you're getting for a lot of times you're getting Fertilized by another different plant that plant produces a seed that seed goes off floats off and the fruit floats off And it gets eaten the seed falls down to the ground and then it grows a new shoot and it's genetically diverse from the original stem But when it reproduces otherwise the different ways then you can't then it's it's not genetically different, right? so It's a low diversity. So it's not beneficial to the plant in the future to the plant survival because diversity is better and many of the nature situations Because if something ever happens to a specific gene where the gene won't survive So if something happens to the the area to the habitat, right? Say some water quality comes bad or the temperature gets really really high and The species is mostly the same genetic type Or they're very similar and that gene that's not do well in this new event Then all that will die off and then it would be hard to come back But if it's genetically diverse and there's some part of the gene Of that species of that population that actually survives in those conditions then it might persist So it's very so this part is really a last-ditch effort to survive in such a high Sailing area and it looks like that's that's the main explanation for this, but I'm sure there's gonna be more research That's gonna be told on there What I why I wanted to I know this might be a little more complex than what we normally look at But this is something I find interesting and knowing because Seagrass beds are so important to tropical systems to not only just our coastlines in general But also to the life histories of many species that live in the ocean also the dudong pot There's a big dudong population in there because there's such a high seagrass level Dudong feed on seagrass and vegetation So it's important to keep the seat to understand what's happening with these seagrasses to better manage them and understand that this species may not do well and They may not be genetically diverse in these areas as opposed to other areas that have maybe lower lower salinity But it's very interesting to see you know to for management purposes to see how these species react if Temperatures are getting higher in the future like everything is predicted like everything's happening Salinity is gonna get higher because you're gonna get more evaporation of why the salinity the salt content in the wire doesn't go away It just becomes more more concentrated. So that means that could pose a lot of problems for this species Okay in the future. So it's good to know about this kind of stuff and it's just it's very interesting and if you've ever gone diving I I'm gonna tell you a little a quick little story I went to Jamaica one time with with my wife and we went we were in a nice cottage over in Port Antonio Great little place on the northeast side of the island and we lived in just it almost like a cottage We had a dock that went into this bay And it was a very protected bay There was a breakwater on the on the east side and then there was a nice good current that you could basically float on one side of the bay and Then go to the next like it without even swimming if you wanted to so we did that and we would come across these seagrass Meadows and it was great is right before Actually, the seagrass. Yeah, the seagrass meows were closer to the coastline You had the quote you had the breakwater then you had the coral reefs right there and you had the seagrasses And now we're snorkeling there the seagrasses are probably about four feet of water Excuse me the coral reefs were almost at the surface and then it would get deeper towards the shore It get I think the deepest it got was nine feet and what we saw like it was really cool Because you would go over you just hover over these seagrass meadows and like you said you're just about four feet above them And when you look in and you kind of dive down and you see there's there's things in there You know, there's stuff moving around in there and if you gently separate What I've watched you I didn't separate when I first hovered over the the seagrass meadows I look down and I see this beautiful These beautiful big blue eyes looking back at me. I was like oh my gosh Then this thing this this fish just hovered over the seagrass meadow maybe about a couple of inches And he's looking he's looking right at me and I kind of dive down to get closer and it's this beautiful pufferfish And it's just gorgeous got big big blue eyes a little mouth and it almost looks like a baby's face It's really it was really cute and then all of a sudden as I went down closer all these other puffer fish kind of just you know Started to rise out of the out of the seagrass meadows and these were tiny like they've arranged in from three inches to You know really small, you know three inches to maybe a inch and a half very small some of them were a little bigger some of them were about six inches long But they're they were gorgeous and I didn't touch them. Of course following my own kind of thing I did separate like I just kind of looked at the the seagrass meadow a little bit by separating them a bit And then there'd be a pufferfish fish that would come out none of them puffed up because we stayed their distance away and But they were just it was just beautiful and it just goes to show the value of these seagrass meadows Even if we don't see it even if we're hovering over these things and if they didn't pop out You know there's something in there. You know that it's important So that's what that's that's the I just wanted to share that story because it was just it was Aspiring to me being like yes, normally in when we see pictures of seagrasses. We just see seagrasses however, when you can actually Look in and see what's in there and how valuable they are because they can hide the fish and inverbers can hide so well Then you realize how important it is that these seagrasses are there So I just wanted to share that story with you guys. I thought it was pretty important But that's all for the show today. Again, if you guys want to support our our campaign on patreon and support our ocean conservation Conservation message and sharing it with the podcast community. You can do so at speakupforblue.com Patreon P-A-T-R-E-O-N and of course as usual if you want to look at our show notes, you can do so at speakupforblue.com forward slash session 107 Which will be the session notes for this Podcast so thank you very much. We have all the links of all the websites that I discussed Some pictures of some seagrasses on there And thank you very much for joining for listening to the show. I hope you enjoyed it as much as I did You've been listening to speakup for blue podcast. I am your host Andrew Lewin happy monday. Happy conservation You You (upbeat music) (upbeat music) (upbeat music) (upbeat music)