Coral reefs and climate change

Jen: Welcome to UTS Science in Focus, a free public lecture series showcasing the latest research from prominent UTS scientists and researchers. I'm Dr. Jen Matthews, a marine biochemist and coral reef researcher here at UTS, and I'll be moderating for today's event. So I'll be collating your questions and asking our speaker these questions at the end of the talk. Firstly, I would like to acknowledge the Gadigal people of the Eora Nation upon whose ancestral lands our city campus now stands. I would also like to pay my respects to the elders past and present, acknowledging them as the traditional custodians of knowledge for this land. As coral reefs are the focus of today's talk, I would also like to acknowledge the continuing sea country management and custodianship of reefs across Australia, including the Great Barrier Reef by Aboriginal and Torres Strait Islander traditional owners whose rich cultures, heritage, values, enduring connections and shared efforts help to protect the future of the reefs for future generations.

Jen: So just a little bit of housekeeping before we get started. So with this being an online event, do bear with us. If there are any technical issues, we will work quickly to resolve them. And if you find that you're not able to access the talk at any point, please log out and log back in again, as that usually resolve these issues. If you have any questions during today's webinar, please type them in the Q&A box in your Zoom control panel, and we'll do our best to answer the questions along the way. If you like a question that someone else has asked and you would like it answered then you can use the upvoting tool, which is just the thumbs up next to the question itself. So the session will be recorded, but we will not be recording any video or audio input from the audience. You may contact UTS at Science.Future@uts.edu.au to discuss any concerns you may have.

Jen: So today you're going to be hearing from Dr. Emma Camp, a marine biologist and the deputy team leader of the Future Reefs team here at UTS. Emma is an award winning researcher, including 2020 Time magazine Next Generation Leader and was recently named the winner of the Macquarie University Eureka Prize for Outstanding Early Career Researcher. Emma researches and advocates for the world's marine life under threat from environmental and climate change. She is one of the founders of the Coral Nurture Program on the Great Barrier Reef, a unique program involving scientists and tour operators to enhance research, biodiversity and promote site stewardship. Emma is an advocate for women in STEM and improve climate action. So to get you in the mood for Emma's talk, I would first like to take you on a virtual dive into the importance of coral reefs.

Jen: So more than 70% of our world is ocean. And while corals occupy less than 1% of that, they are exceptionally valuable. They provide food, livelihoods and economic opportunity to more than half a billion people in over 100 countries. They provide coastal protection from increasing extreme weather events and have been the source of novel medicines, including treatments for Alzheimer's and cancer. And they are teeming with life, hosting a quarter of all known marine species. Corals are living organisms and the foundational builders of reef. And just like every living organism on this planet, they need a healthy environment to survive and thrive. But the ocean and climate change are inextricably linked, and climate change is increasingly altering the ocean's chemistry, rising sea levels, warming ocean temperatures, shifting currents and increasing weather volatility, all of which affect coral reefs. And very quickly, our reefs can change from productive, thriving underwater cities to desolate waterscapes, absent of corals, fish and all the ecosystem services they previously had to offer. In fact, 14% of the world's reefs have been lost in the last decade. And if we continue to allow extreme changes in our environment without action, coral reefs may not survive the century, and the survival of our planet depends on healthy coral reefs. And this is why the research, dedication and action by pioneering researchers like Dr. Emma Camp is critical for the future of our reefs. And it's my absolute pleasure to introduce Emma, who is going to lead us down an exciting path of how corals that are already living in extreme conditions offer natural laboratories, helping her to design conservation strategies to help safeguard the world's reefs.

Emma: Thank you, Jen. Thank you, Jen, for that gracious introduction and for telling us about the value of the reefs and the state of the reefs. And what I would say is that this brings us to a pivotal point in time where we need change. And this has really been kind of cultivated in the fact that it's the ecosystem decade of restoration. The United Nations have also made it the decade of ocean sustainability. So collectively, we're realising that the state of the environment needs change, particularly the oceans. But how do we achieve that and how do extreme environments contribute to that need for change? And that's what I really want to talk to you about today. So globally, we are seeing that our reefs are on this downward trajectory. They are at some starting point, which varies depending on location, habitats, and even within a reef we see a lot of variability. But concerningly around the world, we're on this downward trajectory. For those of you that have been paying attention to the news recently, you would have seen in the last few days that Australia stated the Environment Report came out and what this highlighted is that here in Australia all of the environment is being impacted by climate change. We saw that marine life as a whole was classified as good but degrading and under increasing threat. But importantly, within the marine category, coral reefs were singled out as being poor and degrading. And so this is really a concern not just for us as scientists, but for all of the people that fundamentally rely on the services that coral reefs provide.

Emma: So the question then is how do we get to a point where we can change? How can we either reduce the rate at which we're seeing this decline? Or more importantly, how do we actually change that trajectory? How do we start to improve coral cover, improve diversity, and ultimately ensure that the services that the reefs provide that are so valuable to people around the world continue into the future. And this is a challenge that we are currently faced with. So I'm going to talk through three ways that I think this change can be achieved and then talk about how extreme environments feed into these three headings. So the first is that we fundamentally have to address climate change. We need to come together. We need collective targeted action to ensure that we address the root cause of climate change. And without that, any other actions are going to be futile and short lived. Now other actions that we can take is traditional marine protection. So these are things like marine parks that are vitally important to ensure that the resources that are there are being protected as best as possible from stresses such as overexploitation. So, for example, reduce fishing pressure. Now, the challenge, however, is that marine protected systems have not traditionally been set up with consideration of climate change. And this is something that is going to have to be addressed if we're going to ensure increased conservation under climate change into the future. And I'm going to come back to this point later on in the talk. Finally then is active intervention. And we are at a point now that we know that even if we address climate change, if we have marine protection in place, we fear that coral reefs will still struggle to persist into the future because there has been such decline, but also because there is going to be a lag time between the equilibrium of the environment becoming back to favourable conditions to allow the reefs to prosper again. And this is where, as a researcher, I believe that naturally extreme environments can play an important role into contributing to all three of these factors that we need to ultimately have effective change. So keep this slide in mind. I'm going to come back to this at the end, once I've told you a bit about what extreme environments are and the science that is being undertaken to study them, to discuss how they feed into these three points that we need to have effective change.

Emma: So this is probably a good point to then talk about what are extreme coral environments. And this is a really great question. It is not something that is actually being well defined or resolved, and it's something that myself and some other scientists are currently working to get strong definitions around, particularly as we have an increasing interest in the services they provide. But in all intents and purposes, they are environments where corals survive where we wouldn't expect. So that's where the environments are warmer. They have higher aerial cover, they have high sediment input or low pH, low oxygen, low light. So ultimately conditions where corals are not expected to be found. Corals traditionally have a very narrow range of environmental conditions where they like to survive. But actually, we're realising that corals can survive in a wider range of conditions. So the examples would include carbon dioxide vents where there's low pH, or shallow reef systems that are exposed to air for large periods of time in the day, or places like seagrass and mangrove lagoons, where there is high temperature, high fluctuation in conditions. And the reason we have an interest in these systems is that they tell us how corals can survive under unfavourable conditions. And we know if climate change, unfavourable conditions are increasingly becoming the norm, so these are almost a natural laboratory for us to explore some of the complex interactions that are really hard to tease apart within a laboratory setting.

Emma: Now these two figures here just really capture the fact that this is a global interest now in these extreme environments. The top graph with the red dots shows extreme temperature sites that have been studied in recent years. The bigger the bubble, the more research that is being conducted in that geographic location. And the one below for pH. You can see temperatures being the primary focus of study, and that's because, unsurprisingly, we really have an interest in the effect that elevated temperature is having on reefs because it is one of the biggest stresses that they're facing. But what I want to draw your attention to is the two graphs on the right. And if we look from around 2000, we can see that there's this big increase in research activity in these types of locations. And that has really done two things. One, it has increased our understanding of the capacity of corals to survive in conditions previously thought to be inhospitable for corals. But also it's allowed us to identify actually that if we look, we are increasingly finding that corals do survive in extreme locations around the world. Now, this map's from some work done in 2018. And I can tell you there has been more sites that have been added on since then, but you can see that across the globe, if we look, there are a number of extreme environments that have been identified. Carbon dioxide vents, upwelling sites, high temperature environments. And so collectively there is this network now of extreme systems that we are aware of.

Emma: So for the next part of the talk, I'm going to take you through a case study of mangrove corals. This has really been where our group's work has focused. My passion and love of mangrove corals came off the back of my PhD, where we discovered that mangrove corals were interesting because the conditions were often warmer, more acidic, had low oxygen, varying nutrients than reefs that are only a few metres away. And these are the multitude of stresses that are going to be facing corals as they try to persist into the future. So, I had this real passion around trying to understand, well, how are these corals surviving there? What can we learn? What are the tradeoffs? And ultimately do they provide knowledge to enhance our capacity to manage reefs into the future? So this is going to be very high level just to give a snapshot of some of the research that our group's doing. And I'm going to take you on a tour from the ecosystem level down to the bio cellular level of mangrove corals and summarise what we've learnt to date. So from the ecosystem level, from looking at mangrove locations across the globe now, we have found that they are very different. No two sites are the same and this is really important when we're thinking about how they can potentially be integrated into future management of reefs. A big distinction is that some have reef accreting structures. They actually form a reef. They form that framework which is so important for many of the services that corals provide, such as dissipating wave action, for example, and protecting the coastal system. Whereas other locations just have single coral colonies. So again, whilst they're very valuable for studying from a research perspective, their service value is very different. So understanding that distinction is crucial.

Emma: Moving now to the coral level. And we looked at a bunch of different sort of measurements and techniques to look at how the coral survives itself within these systems. I'm going to highlight a piece of work by a former PhD student, Dr Mickael Ros, and he looked to understand if we incubate corals, how does their physiology change? What can we learn? And so he looks at oxygen dynamics. So he looked for reef and mangrove corals here on the Great Barrier Reef. So the graph, the blue is the reef, the red is the mangrove. And what we want to highlight here is that we saw that respiration increased in these mangrove corals and this ultimately led to a change in gross photosynthesis. And the take home for that is that there are differences in the way that these corals in these mangroves actually produce their energy, their functional physiology. And this, again, has to be considered if we are thinking about moving these corals, for example, active restoration, we need to understand that they behave differently. And understanding how that behaviour is altered in new environments is a research question we need to understand when trying to think about the value these corals may have.

Emma: The next level of research we've been looking at then is the coral skeleton itself. So the coral is an animal and it has this tissue that is over the top of a calcium carbonate skeleton. And one of the questions we've been wanting to understand is how is that skeleton different in the mangroves relative to the reef? And this is a piece of work that was being led by a previous Honours student Annabel, and is currently continuing with collaborators in Israel, Dr Tali Mass. And so this is just to kind of give you a snapshot of the types of questions we're asking. So this is some SEM microscopic images of how the calcium carbonate is actually deposited. And we can see that there is potentially differences in the way that the aragonite crystals are laid down and also differences in the shape and design of the coralite structure. So the questions we now want to understand is how does this translate into differences in physical properties? Are the mangrove corals weaker, for example? Do they have greater porosity? And understanding this information can really help us kind of evaluate the trade offs, but also understand the risks that corals have if they live in these really hostile environments, that we have to remember are representative of what we're going to see increasingly into the future.

Emma: The next level then that I want to take you to is algal symbiont. So the coral is what we call a holobiont, a whole biology. So we have the animal, we have a symbiotic algae that lives in partnership with the coral. And that algae is really fundamental for providing a lot of the resources the coral requires. So we've looked at the diversity of the algal symbiont in many locations, and I'm going to provide a case study from New Caledonia in in particular, because this really represents nicely what we've seen across a variety of habitats. So in this table here, you can see two habitats, reef and mangrove, and then along the top three coral species. So A. muricata and Porites lutea and A. pulchra. Now what we looked at was for each of these different corals, what was the diversity of algal symbionts that was associated with them? And for those that are really interested, these are what we call the ITS2 profiles, but it's basically showing the genetic sequences, the diversity that was returned. Now, the take home from this, if you're not someone that is so interested in the molecular aspect, is that for some species, we saw a difference in algal species that associated with the corals. You can see with A. muricata they were actually the same, but for the other two species, they were different. Now what this tells us is that there's no single mechanism or no single relationship that seems to be universally applied to survive within these extremes. And this is crucial because if we're thinking about how we may utilise these corals in active management in the future, we have to think that there is no single coral or no single algae or no single partnership or mechanism that seems to be supporting that survival. So ensuring that we're capturing diversity is really going to be fundamental.

Emma: We're going to go even a level further into the microbiome. So this is things like the bacteria, viruses, microeukaryotes that are associated with both the algal symbiont and with the coral itself. And for this piece of work, I want to showcase and highlight some work of a former PhD student, Trent Hayden. He looked on the Great Barrier Reef at this coral species for Pocillopora acuta to see how the bacterial communities changed over time. Now the graph that you see here is just from the beginning of his work at one point in time. And what it shows us is that the bacteria that associate with these mangrove extreme corals are very different to that on the reef. So again, the implications for this are complex but also really important because again, it's telling us that there are these strong biological differences between the two species. But taking that a step further, if we starting to think more about what are the active interventions that we may as scientists want to consider, actually manipulating the bacterial assemblages is something that's being considered and like humans have their good microbiome, the same is true for corals and we're realising that they've got these functional differences that we're still trying to uncover. But if we know that these corals that live in these extreme environments have very different microbiomes, that could be a good place for us to start to focus our efforts to understand, well, which of the bacteria there that are may be beneficial or causing harm to further our knowledge of corals, especially moving into that scene.

Emma: So the last part of the research that I really want to talk about is resource exchange. So for corals to be successful across different environments, a fundamental aspect is that they can exchange resources. If everyone is exchanging resources efficiently and have what they need, they are happy. They stay in symbiosis. All is good. However, if that breaks down, that's when we start to see things like coral bleaching occur because of a stress event and then the resources available start to change between partners. So the current focus of a lot of our research in the group at the moment has been around something called the coral elementone and the coral biogeochemical niche. So the elementome is basically the makeup of the coral and algal symbionts' elemental profiles. What are the fundamental building blocks that the coral has and how are they distributed relative to what's available for them in the water column? Now, the reason that this is really important is that we know under climate change, resource availability is going to change. So we need to understand, first of all, what are the resources corals need to survive, particularly during stress, and then how a resource is going to change in the future. And ultimately, are the two going to match? Because if resources change and what corals need is going to change and resources aren't available, then we can again see that there could be issues in how corals may survive into the future. But also we can start to target maybe locations where there are favourable resources to support coral survival. So the work we've been doing at the moment, you can see an example here of the biogeochemical niche from a reef coral. You can see a variety of elements that are basically showing the spread of the spatial distribution of the reef coral. And what we see is that the extreme mangrove corals have a different biogeochemical niche. They require different elements to thrive and survive in that environment. So moving forward, we want to understand more about how the biogeochemical niche shapes the ecological success of corals, both within extreme environments but also during stress events.

Emma: So collectively, then what have we learned from studying these marine extreme mangrove environments? Well, we've learned that they're prevalent globally. And this is really important. They're not just located here on the Great Barrier Reef or over in the Red Sea. We're finding them globally, which means that they could be a viable management consideration when thinking about active intervention. In saying that, they have unique conditions. And this is part of what makes them extreme environments, but also they're different by location, by region. And so understanding and categorising actually what is the characteristics of a given extreme environment is crucial to make sure that we really understand what service provisions it may or may not provide to ensure that if we include that in intervention, we're not overpromising and under-delivering on services provided. We are learning that some corals are really, really tough. Now, this is definitely not to say that these extreme corals are going to save reefs. By no means is that the case. But they do provide some hope and potentially some innovative routes for us to explore, to help buy time the corals when we address climate change and also ensure that other mechanisms are in place to ensure and support their survival. And finally, we know that there are trade offs. For example, I mentioned that some don't have that accreting restructure or they grow slightly differently. And understanding those trade offs are key to decide, well, how can we use those corals to better support resilience and management in the future?

Emma: So I'm going to go back now to that slide that we had at the start where I said, how can we have change? And I talked about addressing climate change. I talked about marine protection and I talked about active intervention. And I now I want to kind of come back to this full circle to explain how extreme environments and the knowledge that we're gaining from them can feed into these these changes that we need. So first of all, these systems are a natural laboratory. We can see how change that we're going to experience under climate change, that we are experiencing under climate change, impacts these corals. And that is crucial to provide evidence towards policy and management as to why we need change, but also to help us direct the science and the scientific questions alongside laboratory work to make informed decisions moving forward. The next then is that they can help to update traditional marine protected parks to account for climate change. One of the challenges I said is that marine protection, so such as marine parks, were not set up to account for climate change. But there is a way to do that through something called adaptive networks. We can include areas where we know they have greater resilience to future stresses within marine protected parks to kind of provide this adaptive network globally that will increase the resilience of the system. And I recently put together a portfolio approach of how this could be included in marine management to help decide are there extreme sites that should be included in management and how could this be achieved? So the first thing is, if we include these extreme systems, we're increasing our diversity of reef portfolio that's being protective. And this is really important because we know that diversity increases the probability of this success and reduces risk. This is something that is often done in the finance sector, and the same applies in all intents and purposes to conservation efforts. These extreme systems have unique services. They have unique capacity to either buffer stresses or to house resilient corals that make them a value to be included in this portfolio. This can't be done without considering risk. And the way to maybe do this would be to consider the probability of stress and the impact of such stress if it occurred. For example, how are these systems themselves going to change into the future? How can we include them so that we are not overpromising and under-delivering on the services that they may or may not be able to provide? And this goes back to having that diversity of reef types within the portfolio of conservation to try and reduce that risk. And by considering all of that, we can then assess how best to include such service provisions that these extreme systems may provide into an active management framework.

Emma: Now, when we talk about active intervention, we're talking about actually having scientists, conservation engineers, managers intervening to try to buy time for corals, where we get our action on climate change and we have effective marine protection. And the one way that extreme systems can feed into this is by being hot spots of resilience. Now on the right, there is a selection of types of environments that have been identified as potential hope spots for reefs. This includes things like refugia, contemporary near pristine reefs, hope or bright spots, and also these hotspots of resilience. So there are a number of services that hotspots of resilience could provide for active intervention. I'm only going to touch on a few for the sake of time. The first of these is that they could be targeted for assisted evolution. Some of the activities that we are currently exploring as a research community, is there a way to speed up evolution within a lab or within nature to increase the likelihood that the corals will survive through in the future? So targeting or using corals from these extreme environments could be a good platform. I mentioned this earlier on, but probiotics and considering beneficial microbes is something that is increasingly being considered in the research community. And again, using these extreme corals can provide a good platform for making decisions over which bacteria we maybe do or do not want to include. The next is managed relocation or transplantation of these corals. Are there areas that are degraded where we can move corals from these extreme environments to try and give resilience to the parts of the reefs that are being eroded? And finally, can we use these corals as a template for synthetic biology? So if we're looking at genetic manipulation, is there a blueprint that we can take from nature looking at these extreme environments to help guide our efforts? So for me, really, these extreme environments are part of the nature based solutions. Let's not try to rewrite what nature has done for us. Let's work with nature to see how best we can move forward.

Emma: Now, I'm going to focus in on this idea of managed relocation and transplantation, because it really dovetails nicely into some of the activities that we have with industry partners as part of the Coral Nurture program. Now, I'm only going to have this one slide to talk about the current program, albeit something I'm very proud of and very excited to talk about and could talk about for hours. But Professor David Suggett will be leading the next Science in Focus all around the Coral Nurture programs. So definitely make sure you join in for that one. But the reason that I want to touch on this is that this partnership is a unique partnership between science and tourism, traditional owners coming together to try to increase the resilience of highly ecological and economical value sites on the Great Barrier Reef. To date, we've had around 80,000 corals that have been outplanted, but the key is that we need to futureproof those activities and this is where extreme corals and corals with natural resilience are crucial to the activities that are going on. On the right hand side there, you can see a series of stress testing assays that we have conducted to try and actually identify within the natural population, which corals have enhanced tolerance to persist into the future. And so it's these sorts of collaborative approaches that include the industry and science partnerships that are really going to be crucial to buy time and ultimately help ensure and conserve the reef into the future.

Emma: So to ensure that we have a long time for questions and answers, this will be my last slide. But I wanted to take this quote that I found in the State of the Environment report because for me, it really sums up the state of where we're at. "We need immediate action with innovative management and collaboration to turn things around". And this really resonated with me because the situation is poor for reefs. We know globally that the trajectory continues to decline. It provides anxiety for me as a coral researcher every time we see the headlines and we read the research. But in saying that, we have the tools and capabilities to make a change, but it's going to require this collective effort for everybody, not just the scientists, not just the policymakers, but every individual to come together to unite for the reef and nature as a whole to ensure that they persist into the future. So this quote really captured that for me, and I hope that this is that pivotal point that we now see the positive change that we need to ensure the reef is conserved into the future. So thank you for listening to our 20 minute brief round up of all of the activities that we have going on within the group around extreme environments. And at this point, I would really love to take some questions. So thank you.

Jen: Thank you so much, Emma. That was an incredibly interesting and important topic. It's really interesting to hear just what the extreme corals have to offer and it is kind of  excites me as a coral biologist as well, the opportunity is out there. So just before we get started with the questions, I just wanted to remind everybody that if you have a question, please pop it in the Q&A box. And if you like one of the questions that are already there, then feel free to upvote those questions. So I'm going to kick this off because I have a burning question. How many locations of extreme corals have been kind of already found?

Emma: That's a great question, Jen. So there's up of 100 at least, if we consider kind of all of the sort of broad types from upwelling sites to the hot reefs to the mangrove locations. But as I was kind of alluding to, the more we look, the more we find and this is the thing about these kind of extremes, if you like, is it's challenging our perception of where and how corals can survive. So I would argue the more we look, the more we will likely find.

Jen: So do you think, are there other areas even around Australia that we haven't yet looked that we could potentially tap into for these extreme corals?

Emma: Yeah, definitely. I have received a few emails from people in Western Australia saying, oh, we've got corals in the mangroves here, you need to come and have a look. And so again, that's just one example. But I definitely think the more that we characterise the reef environments, the more we're realising that actually, our understanding of where corals are typically found is maybe not as narrow as we originally perceived.

Jen: Yeah, and you mentioned at the end, so there was this opportunity to perhaps transplant some of these more resilient mangrove corals into the reef. And somebody asked a question about that. So are there any risks with moving mangrove corals to a new environment?

Emma: Yeah, that's definitely a great question. And kind of within that risk framework I was talking about, we absolutely have to consider those risks and there definitely is potential risk. The worst thing we would want to do is move a coral that has a pathogen or is going to become kind of some freak Frankenstein takeover coral of the reef. And so we're really mindful of that. And so when we do these sorts of transplantations, it's done in an iterative way to try and minimise any risk. So an example would be that they are initially transplanted on racks to kind of isolate the coral from some of the surrounding environment. And we're mindful of when they would reproduce to make sure that they're taken out from that environment before they they're reproductively active, at least until we've got the knowledge to say we don't perceive any risk and we can move forward. So definitely risks, but it's a risk-cautious approach we're taking to explore these interventions.

Jen: Yeah. And I guess with the harmful, potentially harmful things that carry a risk coming with them, it could also bring benefits, maybe new fish or new crabs or other invertebrates. Have y9ou seen that occur on the transplanted corals?

Emma: So yeah, that's that's a great question and not something that we've specifically looked at with the mangrove corals. But I will say that through the Coral Nurture program, one of one of our PhD students is looking at how the structures can provide like a unique habitat for marine life. And we're definitely seeing unique fish come into a unique habitat created by the frames being there. So whether or not the same applies with these mangrove corals is yet to be tested.

Jen: Yes. So these corals do offer potentially an opportunity for not just the coral cover to increase, but also the other things that comes with a plentiful coral reef like the fish and other organisms. So another question I have, which is a really interesting one. Are mangrove corals as colourful as reef corals?

Emma: That is a great question. So yes and no. It depends on the species, but this is actually a really interesting point. So when you look above the water down at mangrove corals, they often look paler. And if we take pictures or videos, they often look paler. But when we've taken a coral fragment from the mangroves above water and actually process them, they look as colourful and they've got as many colourful pigments in them. So we actually think that sometimes it's the optics of the mangrove water that make them appear paler than they actually are. So short answer is no, they're not any less colourful, but the long answer is actually they may appear less colourful, but it's just an optics of the water difference at these mangrove locations.

Jen: On the questions, somebody has asked, and I think maybe this ties in well with this, but how does coral bleaching occur? So I think that probably ties in well with what you just said.

Emma: So yeah, it's a great question. So bleaching is a sort of physiological response to stress. Primarily, we hear about it in relation to thermal stress. So the coral is that holobiont. It's an animal with that symbiotic algae that is so important for the coral as a whole to get the resources it needs. But during times of stress, the algae actually produce some toxic elements to the coral and they are expelled. And at that point the colour sort of leaves. We see the white skeleton underneath the tissue and we say that coral bleaching has occurred and that can occur not just from temperature stress, from any stress, but temperature's kind of the one that we hear most about in Australia because of the thermal stress events that we've had.

Jen: So there's one question that's been upvoted nine times, so I feel I should definitely ask it! You did touch on it a little bit as well already, but can these more robust corals help us in genetically modifying other corals to better adapt to climate change? Now, I know you mentioned adaptive evolution, so perhaps this is related to that.

Emma: Yeah. So for me, what these sort of extreme corals, wherever they're from mangroves or from hot seas can do is provide sort of the blueprints. If we understand the genetic changes that they have naturally undergone, arguably over sort of longer timeframes than we can reproduce in the lab, that can give us a blueprint of maybe where we want to start if we're going to look at genetic modification. So that for me at least, and that's obviously my opinion, would be one of the ways that they could inform decision making in that sort of synthetic biology angle.

Jen: I guess, is that comes with a whole new level of challenges around genetic modifications and all of that jazz. So we have a question from Professor David Booth. So he said, hi, Emma, great talk. However, given the Great Barrier Reef supports billions of corals currently exposed to stresses such as bleaching, do you really think intervention will ever have any meaningful impacts at the Great Barrier Reef scale?

Emma: Hi, Dave, and great question. We're not without climate action. We fundamentally have to address climate change. I stand by that 100%. But I think that we are already seeing at local scales, not necessarily the size of the Great Barrier Reef, but at local sites on the Great Barrier Reef, that these interventions can make a difference. And that is from multiple ways. One, about education and engagement, which is crucial, I think, in ensuring that we have a future of the reef. But also if the worst happens and we continue to see this decline on the reef scale, these arguably pockets of resilience are going to become increasingly important, because for me, the worst case scenario would be that's what we have left to try to boost the resilience in the future. So by no means are these a silver bullet to save the whole reef, but they can provide, I believe, these targeted pockets of intervention that, worst case of what we have to boost the resilience into the future, when we hopefully get climate action happening to the level we need.

Jen: Yeah. So as you said, it was more, you know, doing these kind of restoration activities is buying time. The biggest thing that we need to focus on is climate change. But if we manage to resolve climate change, then we need a brood of corals to build back our reefs. So if we don't do things now, even if they are only successful at a small scale, then those corals won't be there to repopulate reefs. So it is really important what you're doing.

Emma: Thank you. And I think to add to that what you just said, Jen, I think another thing is, and this is really highlighted in the environmental report, is that we need innovation, we need collective collaboration and innovation. And I would challenge anyone listening that, you know, in other industries, engineering, to how can you help us upscale what we're doing. And again, I think that's the point, is that we also need to get to a point where these local solutions could potentially be scaled up to be more effective at scale. And that's definitely something that myself and other scientists are trying to explore. But again, it never negates the need for climate action.

Jen: Yeah, absolutely. And as you say, the transdisciplinary collaboration is something that's really only just starting to creep into the coral reef realm, I feel, as a researcher. And but there's so much untapped knowledge in that space and some of the potential things that we could do and practices that are already helping with restoration on land that haven't been attempted in reef systems, obviously being underwater, it's a bit more challenging. But yeah, I think that's a really good, really interesting point. So and something that someone's asked which given the weather in Sydney at the moment I think is highly relevant, what impact, if any, does flooding events have on corals?

Emma: So those are great, great question. Actually say that it's really, really relevant for the mangrove and inshore environments and it can be devastating. So one of the biggest impacts that we've seen so far on some of these extreme environments, such as these shallow mangrove lagoons, is freshwater input. So if there is severe rainfall, especially if there's rivers nearby and that comes onto the reef, it can bring in fresh water, it can bring in sediment, change in nutrients, all of which are not good for corals. So definitely a problem. And again, for me, that's where this risk framework of how do we actually spread the risk to maximise the chance of saving some coral stock is an important consideration for us as managers in the future.

Jen: I guess, you might think that with rain, if you're bringing loads of nutrients into the water, well, surely that's good. Those nutrients will help corals grow. But I guess that's not really the way that it works. And alongside the nutrients, you've got all the bacteria that have reefs haven't been exposed to and viruses. And that's how we're getting more and more diseases as well on top of that. So yeah, it's really, it's one of those things that I guess now Australia is having frequent flood events unfortunately. So it's another nail in the coffin I guess for reefs if we don't do something.

Emma: Yeah. And it's this layering of stresses that is so challenging. We know that reefs can recover if they're given the capacity to do so, but they are just getting one stressor after another after another. And that's the problem. They're just not getting the time to show their natural capacity to recover. And that's where, if we can find ways to just give them some boost, it's helpful given all of the stresses that are being thrown their way.

Jen: Yeah. So I think that ties in really well with a question asked by Kevin. So when corals are relocated from their extreme environment to the reefs, have you found that they retain that resilience kind of features or physiology over time?

Emma: So that's a great question. And we've had a couple of kind of research projects that aren't published but have been looking at this at the moment. And we are seeing that, at least for the couple of species that we've looked at, they do stay and retain their tolerance. And so that's something that we're really interested in, in terms of how long that may be the case. So we don't have all the answers yet, but that is definitely something that is sort of a current kind of research question for us to understand, because obviously if it's eroded, that really changes their potential value or arguably highlights the kind of need to conserve the specific area that they were originally in. So it has repercussions for how we consider and manage those systems.

Jen: Yeah, wonderful. So from a year five class in Sydney, can isolated coral colonies survive on their own?

Emma: Great question. Hello and thank you for joining. That's a great question. So they can survive on their own. But obviously the services that that isolated colony provides is very different to the reef itself. And I kind of touched on that before, but obviously we're not just interested in one or two corals. And that kind of goes, I think back to what Dave Booth was sort of getting to earlier, as we obviously want to get to a point where we've got that collective reef conservation status and for that to be successful, we need enough colonies to be reproductively viable, to have enough diversity so that when they reproduce we're getting more diversity to sustain that population. And so my answer would be we need kind of enough isolated populations to have that diversity to ensure that it does kind of continue into the future. But yeah, it could survive, but it may not provide all of the services that we ultimately want from the coral reefs.

Jen: Yeah. So and I guess as well, if the environments are changing, they're not just changing on the reef, they're also changing in the mangroves as well. So what does the future look like for these already extreme locations? Are they going to get extremer?

Emma: That is the question. That is a great question. And from the evidence that we have so far, it really depends on the location. So we know, for example, that in the Kimberleys region, it's an area in Australia where we've had some extreme corals and they were thought to be quite tolerant, but then they experienced bleaching and they were just as susceptible. Some of the species are actually more susceptible to stress because they hadn't experienced it before. Whereas other locations we've seen that they seem to be kind of buffered in some capacity to the stresses that we're seeing. And so, part of the way we're trying to answer that question is now to kind of simulate some stress testing on those resident corals to see how far we can push them. So as an example, some of the Great Barrier Reef mangrove corals, we have put in the stress testing assays and we've had them as warm as 39 degrees and they haven't shown bleaching, which is unprecedented really for corals on the Great Barrier Reef. But that's not to say that they haven't been physiologically impacted and that's now what we need to kind of understand.

Jen: Yeah. So as you said, there were expanding kind of ranges and oh, sorry, you were saying that you're testing them to see if they can survive even more extreme conditions. So there was a question that has been asked about corals moving into Sydney Harbour in greater numbers. So is Sydney Harbour an extreme condition?

Emma: So it's a great question and this goes back to our complexes of what is an extreme environment and it sort of falls into a marginal extreme environment. The conditions are less favourable than the reef environment in terms of sort of the pH for example, it's considered less favourable, but maybe the temperature is not as warm, which is favourable, but then it's cooler. So there could be cold stress. There's lots of kind of variables that we have to consider. But Jen, this may be something you want to add in, as you do a lot of research on these corals moving south. So I don't know if you want to say a little bit more on that topic as well.

Jen: Yeah, it was a really interesting question because as you said, it's something that I research a little bit, but seeing it posed in a question as an extreme environment, I've never really considered it like that before, but I suppose it is for corals in tropical areas to expand to temperate areas. For them, it's extreme. And I guess a really important kind of natural variation that it would be worth paying attention to is whether they over winter, and whether they survive and whether they reproduce and all those kind of very sensitive variables that they've adapted to on reefs like temperature control, reproduction and all that kind of processes. Is that the same in Sydney? Can we see other populous? At the moment? There's only a few corals that have migrated down to Sydney as far as we know. So is this process applicable to other species of corals? Is Sydney going to be the next home of the Great Barrier Reef? Hey, I'd love it. I could just dive straight out of university. That would be wonderful. I'd love that. And so there is another question. So differences in endosymbionts and microbiomes in mangrove versus reef corals are related to different food availability. If so, how this might affect the energy budget to mitigate stress?

Emma: Okay, there's a lot going on there, so I'm going to try and unpackage that. So great question. So we don't know the exact drivers of the differences, but one of the things that we hypothesise is that, that it is the available resources that ultimately these symbiotic partnerships that evolved over thousands of years have fine tuned to provide each member the resources that it needs. So ultimately, as the environment changes and as habitats change, how these partnerships may evolve is something that we don't really know, but ultimately is definitely possible, especially when we think of the algal symbiont. It's not just a single species often that is found within the population. And we know, for example, after bleaching events, you may see differences in both the algal and bacterial communities of a recovered coral. So it's entirely possible that as we see change, the current partnerships may change as well to favour the new resource environment. So yeah, it's a great question and definitely something that I don't think we have fully resolved, but is the sort of line of thinking that we are looking into to try and help better predict what partnerships may or may not be successful and where they may or may not be most successful.

Jen: Yeah, that's great. So all this research that you're doing and all these corals that you're experimenting on and these trips and everything like that, there's a really interesting question from John Ridge. Are you concerned about the negative impact of research projects and the aquarium industry, both domestic and commercial, on the world's reefs?

Emma: Yeah, look, this is a great question. And definitely something that we have to consider is something that we are definitely mindful of. The ultimate question is, is the research that we're doing worth the cost of the research that is happening? And we believe yes, if not, we wouldn't wouldn't be doing it. But it's definitely something that we're always mindful of. So examples would be if we take coral fragments for analysis, it's always the minimal amount that we can take to have the least impact on the system. And as a team, we've looked to cut down our travel, for example. We're obviously not based on the Great Barrier Reef, and we know that when we go out there that has a footprint. So we've looked at ways to combine trips to minimise air travel. We've driven up there sometimes. So look, it's a great point and I think not just research but any activity that is looking to have a positive impact. We have to consider the whole process, the whole cycle to really question whether or not is having a benefit. But for me, the worst situation we could be in is that we have a situation where we've lost most of the reef. We need to intervene immediately because it will be lost. But we don't have the knowledge or the scientific backing to know how to do that most effectively. And that's where the science and the research, particularly when it's focused around this intervention and that decision making framework, I think outweighs some potential risks that it could be having or the costs that it could be having.

Jen: I guess one of the ways that you're helping to mitigate any kind of coral losses, that you're also replacing coral by growing them up in these coral of these fragments of opportunity. I know you're not mentioning about the coral nurture program, Professor Suggett's next talk, but that's kind of a way, I guess when while your research you may use coral fragments, but this research is important to help the existing coral colonies to survive. And without that research, then yeah, sure, we may use corals during our research, but without that research there would be no corals if we weren't able.

Emma: But I also think it's a great question and it's the self check that we should all be having. To be asking is what we're doing. Having the outcome that we hoped for. And ultimately, without the scientific knowledge, policymakers can't make the right decisions. They can't effectively manage the reef without the evidence on how best to do that. If we're going to try and meet our climate targets, we need evidence as to why that's essential and what will happen if we don't. And that's where the research is really so important. But again, it's a great question. It's a great self-check I think we should all have.

Jen: Yeah, I mean, corals are a resource and just like everything, every resource in the world, we can't just take and take and take it for our own purposes and, and I guess permitting and there are policies that help control us. I kind of feel as well there is a more of an emphasis on non-destructive methods of investigation and that's something, I guess, is there any non-destructive methods of investigation that you've applied to mangrove corals?

Emma: Yes, that's a great point, Jen. So yeah, we, for example, developed incubation chambers. So you saw on Mickael's work that the coral had been removed and put in these chambers. We've developed these chambers, made out flexible bags that can actually be put over the coral in situ to avoid the need to remove them. So that's a great example of ways we can try to challenge our previous methods to minimise the impact that we're having.

Jen: Yeah. And maybe where these engineers and other great minds can get involved in coral research and develop new ways of non-invasive sampling. So I have a question here, what does coral eat? That is a good question.

Emma: So it depends on the species and the location and they are filter feeders. They can take in things that are around them or one of the microscopic algae that they like to have. But it's a great question, depends on where they are. And one of the things that we're kind of wanting to understand more about at the moment is what the mangrove corals eat relative to the reef corals. We know that mangroves have more resources available there than on the reef. And so we want to understand what is actually that make up of resource and how does that translate to coral fitness. So maybe if I do another talk in the future or have a better answer to that question.

Jen: So I think we've got time for one more question. And this question has had a lot of upvotes, and it's probably the one that people are most keen to ask, So what are the actions that we can do to help coral reefs? Are there any citizen science projects that we can take part in, or is there anything that we can do in everyday life to help protect coral reefs?

Emma: Yeah, that's a great question and I think that was something I was hoping was asked because to stick to my time limit, I unfortunately couldn't cover it. So the first answer I would say is any action that reduces your own carbon footprint is going to have an indirect and direct benefit on the reefs and nature as a whole. So no matter how small actions may seem, you know, taking public transport, turning the lights off, all of those choices do if everybody collectively does it, can make a big impact. And one thing that I've said time and time again is how we vote. And again, ensuring that we're voting for individuals where, you know, climate and environment is central to me is just a really valuable way if we've got a privilege to vote to ensure the environment gets the attention that it needs into the future. And then there are both local and more kind of regional and global activities that individuals can get involved in. So if you're around Sydney, there is the Sydney Harbour ... I'd have to check the exact name, but it's like the Sydney Harbor Twitter feed where you can report unique sightings. So if you saw, for example, out on a snorkel, corals in your location, you could tweet about it on that framework and obviously let people know. And that's a great way to get involved in sharing the sightings that you've seen. On the Great Barrier Reef, there's this thing called the Great Barrier Reef Census. And it's where people have uploaded pictures that they've taken from the reef and citizen science. So anyone from any background can go on, do a little bit of training, which they provide, and then you can ID Coral and other species from the videos in the pictures. And what that's allowing scientists to do is actually get a better understanding of the mapping of the Great Barrier Reef. We actually don't have great mapping because it's so big. So that's another way that people can get involved.

Jen: I guess if you're diving around Sydney, I'd be interested to know new corals that you've seen. Now, I saw something on the UN website the other day that has kind of impinged in my brain now and it was the lazy person's guide to saving the world and I thought it was wonderful because it was a really good kind of resource that even if you consider yourself a lazy person, it's that things that you could do? And I thought, that is great.

Emma: And so the Twitter account, if you're in Sydney, was Wild Sydney Harbour. So that would be the one that you can put any sightings on.

Jen: Well, thank you so much, Emma, for your talk today. And thank you everybody who attended. I'm really grateful and I'm sure Emma is as well. Thank you for your time. A copy of this talk will be available online and if you registered for the event then you should receive one in the email as well. So if you were more interested in hearing a little bit more about the Coral Nurture program, I just wanted to mention as well, that please to join our future Science in Focus webinar, where Professor Dave Suggett will be talking about the Coral Nurture program and giving you an update on that. But otherwise, thank you so much for coming today. Enjoy the rest of your day.