 Okay can you all see that now? Yes we can. Perfect, brilliant thank you. Okay so hi thanks for the intro. My name is Katie, I'm a postdoc working at the Marine Biological Association in the UK doing work on marine heatwaves and I'm just going to talk to you a little bit today about some of the work we're doing. Okay I'm going to give a little bit of background on marine heatwaves because I'm not sure what background everyone has and how much they know so essentially as we all know the oceans are getting warmer and in line with that we're also seeing heatwaves in the ocean just like we see on land. So there are essentially discrete periods of anomalously warm water that are occurring in addition to background climate change. So if you see this this global map on the side this just gives you an example of notable marine heatwaves that have occurred over the last 25 years and you can see they can occur anyway in any sea any ocean and we get these big blobs of warmer than average water where sometimes the water is increasing to temperatures as much as five degrees above the background temperatures for the time of year in location. So the most commonly used definition of a marine heatwave is a period of five or more days where water temperatures are warmer than the 90th percentile based on the 30-year historical climatology for the time of year and the location. So if you have a look at the figure on the left hand side at the bottom you can see a blue line which is your average temperature for a time of location over the last 30 years. The green line above it gives your 90th percentile threshold over that time and then the black line is your today's temperature and you can see if the back if the black line goes above the green line and then we start to get heat spikes and if it goes above that 90th percentile threshold for five days or more then this becomes what we classify as a marine heatwave at this point and just like many other things in line with global warming marine heatwaves are becoming increasingly common and increasingly increasing intensity as we go through time. So within any event the category of the heatwave can vary from moderate to extreme as the difference in the threshold temperature and the recorded temperature varies. So you have your average temperature and then above that you have your threshold and once you pass that threshold you have a moderate marine heatwave. Now if you take that difference between the average and the threshold and you go to two times that height you get a strong heatwave and then they become incrementally more intense so you get then severe and then extreme and just to give you an idea of how that could vary on the right hand side here you can see a marine heatwave that happened off the coast of Western Australia in 2011. Now you can see with both spatially and with time the heatwave varies from moderate to extreme if you look at the different colours and different areas of the coast were impacted over time with different levels of severity of heatwave. And just to kind of drive home some of the impacts that heatwaves can have and why we're looking at them. If you look at the two pictures above so A and B just on the right hand side there. A gives you an example of a lush kelp forest that was found off this coast of Australia and has been since time began not then but you know since as long as people can remember and this one particular heatwave event caused a 100 kilometre range contraction of the seaweed of this kelp and B the picture on the side is what's left now. So we have these turf algeas very low level turf algeas which don't have the same three dimensional structures and more than a decade later none of the kelp has recovered and we still just have these turf algeas there. Now today I'm going to talk to you about what we've been doing focusing on marine heatwaves of a strength and strong and above and the reason we look at these is because this is where we start to see the more significant impacts of marine heatwaves. We also focus on summer months rather than winter because organisms are living close to their thermal maxima so again we see larger impacts of marine heatwaves in the summer months so this is generally where our research focuses at this point. So what do we know about marine heatwaves so far? We know the impacts can be significant so we can get mass mortality and we can have huge shifts in habitats in relation to them and if you have a look here all these white boxes on this very simple figure here just give you an idea of the global expanse of impacts we've seen that affects foundation species all over the world. Now the work we're doing currently is looking at foundation species but I'll come back into that in a minute but yeah this is just to show you that this is where we've seen broad impacts of marine heatwaves all over the world and this isn't we don't just see impacts sorry again we also know that the impacts we also see huge impact in relation to ecosystem services so this figure is very busy and I don't expect you to take too much away from it but all it's telling you is that globally marine heatwaves have impacted provisioning services regulating services habitat services and cultural services everywhere and in that way the majority of large marine heatwave events start to impact us as humans and this is generally why we care at the end of the day. So just to put some of that into monetary values just to give you an idea of the kind of extent of impacts these heatwaves can have around 2016-2017 there was a large marine heatwave off the coast of southern Chile which caused harmful algal blooms. Now these harmful algal blooms led to huge mortalities in the farmed fish down there which led to a loss of 800 million US dollars in export just for that one season alone and similarly in 2010 the marine heatwaves in Southeast Asia caused huge bleaching mass bleaching of coral reefs and the loss to tourism because people were less interested in visiting bleached reefs was somewhere in the value of 50 to 75,000 for local operators around Southeast Asia so we're seeing huge, huge impacts of these marine heatwaves. So we wanted to start building an understanding of how marine heatwaves of different magnitudes impact different species to see if we could start to see the relationship between some of the more major marine heatwave metrics and foundation species. So we were looking at things like how long do marine heatwaves last, how intense are they, what's the highest temperature we reach and we're looking at how they then impact our foundation species. So we're focusing on foundation species because the impacts of these species are disproportionately high compared to many other species in the environment. In any marine environment the foundation species are essentially the identity of the environment and if they disappear the entire community changes. So this is where we're focusing right now and the work we're doing is looking at kelp forests, seagrass beds, non coral habitat forming invertebrates like these Gorgonians and coral reefs. So to start to investigate how marine heatwaves are impacting these areas, the first thing we did was identify time series data sets for these four different groups of foundation species where we could find long time, long series of data where we had either changes in densities of kelp or seagrass or bleaching events or mass mortality events occurring all over the place. We then explored for every single location that we had data for, we explored marine heatwaves that had occurred in those areas and as I said before we're looking for strong summer marine heatwaves and then once we've done this we cross referenced all of our data for every location we had and we pulled up every overlap where we had time series data and a marine heatwave events occurring and had a look at what we could see there. Okay, so just to give you an idea, kind of a better idea of what we did. This is an example from off the coast of California and it just gives you an idea of how we kind of worked through our data. So at the top you can see 40 years worth of climatology. There's a package called Heatwave R if anyone is using our and wants to look at marine heatwaves which will pull up for any location your climatology. So we pulled up for the coast of California, this particular area, the climatology over the past 40 years and you can see the red arrows above just indicate where there was a strong summer marine heatwave and then underneath you have your change in kelp density. So this is macrocystis, one of the main kelp species over there and you get your density on the side and you got about 20 years worth of data. So here you can see we've got two different periods where there were summer marine heatwaves and we have kelp data from before to after so we can start to look to see how the kelp has changed during a marine heatwave event. So kind of in closer context we for each event we then took a couple of years before if we could and looked at the natural variability and then we looked at a year or so after and we looked at the difference between the averages of density of kelp in this example from before to after and kind of took that as a response to the marine heatwave. So we did the same for seagrass and for bleaching and mass mortality events. We just looked at the occurrence of bleaching or occurrence of mass mortality events that they'll start after or just after marine heatwaves. Okay, so what will we find? Well, first of all we managed to find data from 1,365 sites globally where there were heatwaves occurring strong summer heatwaves that occurred at the same point as we had data for and these across 72 ecoregions. So it's a good global kind of expanse that we've got here. If you have a look on the right hand side, these were the different data sets that I used that were used. They are all freely available, big intense data sets, but if any of you want to know any more about them, my email address at the bottom of all the slides. So feel free to contact me and I can either give you a list of them or any other information you are interested in in these. Okay, once we found all this data, the first thing we did was kind of a blanket analysis to determine how foundation species were impacted within each of these. So this again is an example for kelp here and it just gives you an idea of how kelp responded in different ecoregions to marine heatwaves. We averaged the data from sites within each ecoregion and then looked at changes in kelp from before to after, as I said. So you can see here for every location on average we're seeing about 50 to 60 percent of the time we're seeing a loss of kelp in relation to marine heatwaves, which is no great shocker. We all know they're damaging to the environment. However, what was a bit of a surprise is around 20 percent of the time we're instead seeing gains in relation to strong summer marine heatwaves. So based on this, we then had a look at how species responded across their point in range, across their entire distributional range. So we separated species by trailing edge mid and leading range edges and looked at how marine heatwaves affected species in each of these distribution points. Okay, so first of all for our animals, so for the corals and the invertebrates, we found at the warmer range edge, we were seeing larger impacts than at the cooler range edge. So more coral was being bleached, more invertebrate mass mortality events happened. And similarly for our plants, we again see the same kind of thing where at the warmer range edge, we're seeing a real decline, but at the warmer cooler range edge, we're actually seeing an increase on average in response to these strong summer heatwaves. So it just goes to show anything you're doing, the importance of taking into account where the species is in its point in range and how that affects its thermal capacity. Okay, so after this blanket analysis, we wanted to start looking within eco regions as to see if we could determine in any eco regions, if there were relationships between the marine heatwave characteristics and the responses we're seeing. We narrowed this down by eco regions just to try and take out some of that thermal effect from species ranges. So this, doing this, we kind of also limited our data to anything that had 10 or more data points in, which left us with 29 eco regions globally, and we ran general linear models to compare our responses to the marine heatwave characteristics that we were looking at. So duration and maximum intensity, the average intensity, the cumulative intensity, which takes into account the length of time and how warm the water is over that length of time and the maximum absolute temperature. So what do we find? We found pretty much for every foundation species in eco region, there were significant relationships between marine heatwave characteristics and some of the impacts we're seeing. Sorry, I thought my daughter was coming in then. So just to show you some of the impacts that we saw, this is just for the Caribbean. So this gives you an idea for some of the coral reefs we were looking at in the Caribbean. And you can see that the two most common parameters for, and we found this across the board for coral reefs that kind of predict how a reef is going to respond during a marine heatwave is the maximum intensity of the heatwave and the maximum absolute temperature. So this just gives you a couple of examples. So these are many reefs off the coast of Florida, where we see a significant relationship. And although coral bleaching remained quite low level across the heatwaves, we see this significant increase in bleaching with increasing maximum absolute temperature. And then in the greater Antilles on the right hand side, it's a much more clear cut pattern. And once the temperature gets above 30 degrees, we're seeing huge levels of bleaching. And this was kind of the more common pattern we saw across the board. Most most reef areas we found above 30 degrees, we're seeing this huge increase in bleaching. So just to show you our overall findings, again, this is a very busy figure, but this gives you our 29 eco regions where we have compared the different marine heatwave characteristics to different foundation species responses. You can see in general we've got these significant relationships linking the foundation species with these different marine heatwave metrics. And if we can start to scale this up, we can start to understand how marine heatwave impacts of foundation species in different parts of the world and begin to predict how these marine heatwaves will or how foundation species will respond to marine heatwaves in the future, which hopefully will start to to guide management. So as we all know, nothing's ever quite as clear cut as we'd like. So we're working towards developing the understanding of these relationships between marine heatwave characteristics and foundation species. And as marine heatwave forecasts improve, we'll be able to hopefully guide better management decisions and start to predict better what's going to happen in the future. But doing this also provides us with some hypotheses to start testing in the lab. So this is one thing we're doing back at home is running lab experiments to support what we're seeing in the field, just to try and understand if we can see the same same kind of responses. Yeah, and that's that's the kind of direction we're going in right now. And just to finish, this is the lovely team that I had to spend lots of my time working with. So a thanks to them. A thanks for all of you guys for listening. And with that, I'll take any questions.