Daniel interviewed Dr Nicola Allison, a senior lecturer from the School of Earth & Environmental Sciences, St Andrews University, at the Scottish Oceans Institute. Dr Allison studies how organisms form CaCO3 biominerals, what the chemistry of these minerals can tell us about past environments and how biomineral formations will be affected by climate and environmental changes such as ocean acidification.
SUMMARY KEYWORDS:
coral, ocean acidification, seawater, organisms, skeleton, calcium carbonate, produce, reef, deeper waters, coral reefs, climate change, growing, pressures, algae, structure, algal bloom, important, diversity, pH levels.
SPEAKERS:
Dr Nicola Allison, Daniel Tulloch
Daniel Tulloch
Okay, so firstly, could you just tell me your name? Just I'd like to start off with that.
Dr Nicola Allison
So I'm Nicola Allison.
Daniel Tulloch
Nicola Allison, and what do you do, Nicola?
Dr Nicola Allison
So I do research into how marine organisms produce biominerals. And particularly in the marine environment, a lot of these biominerals are calcium carbonate.
So we're talking about things like bivalve shells, tiny shells called tests that are produced by unicellular organisms. And particularly I work on corals and how corals build coral reefs.
Daniel Tulloch
Really? Okay, and is there, because I worked on a research ship, quite a few years ago with, you might know him, Murray Roberts?
Dr Nicola Allison
Yes.
Daniel Tulloch
Yeah. So he worked on, looking at cold water coral? Which was really fascinating. I mean, I'm not a scientist at all, you know, I'm a seafarer and a photographer, and other things (laughs). And, yeah, it was really quite fascinating. Can you tell me a little bit more about that, and whether there's been changes to that due to climate change, or is there any sort of correlation there?
Dr Nicola Allison
That's right, yeah.
So coral: we're particularly, we're particularly interested in these organisms, because they produce these calcium carbonate structures. And that sits, so that's a structure that's made out of calcium and ions that occur in seawater, so dissolved particles in seawater. And because of ocean acidification, which is caused by the increase of atmospheric co2, we know that the concentration of carbonate in seawater is decreasing. So it's becoming increasingly difficult for calcium carbonate minerals to precipitate from seawater. So we're kind of interested in, in researching that.
And these biominerals are interesting in that they're not, they're not just calcium carbonate, there's quite a lot of biology in there as well. So, so the the organism produces lipids and proteins, which help to control how the mineral forms. So they control the rate at which the mineral forms, and they control the shape of the mineral and, and the organism ends up producing a structure which is often highly ornate and sophisticated.
So in order to understand how climate change affects the production of the mineral, we need to understand not only just how climate change affects the chemistry of seawater, but also how climate change affects the bit of biology that the organism does to build a biomineral. And that's particularly one of the things that I'm interested in.
Daniel Tulloch
That's fascinating. So you're sort of looking at how, yeah, so also that, I guess, that must have sort of ripple down - obviously, it has major ripple down effects as well, because if the coral can't survive, then, you know, that's an ecosystem for - um wow, that's incredible!
Dr Nicola Allison
So this is one of our corals that, this is one that's collected in the field. So each of those individual sort of holes in the skeleton would have been a single animal -
Daniel Tulloch
A single animal?
Dr Nicola Allison
Yeah. And so these colonies, these corals, they tend to live in colonies, made up of many, many organisms. And so this is a massive coral. It tends to build really large skeletons which can be several metres across. So it's a really important species in terms of reef building, but each one of those is about a millimetre in diameter, but it's one of the most important reef building species in the Indo-Pacific.
Daniel Tulloch
Really?
Dr Nicola Allison
So it's a, an animal that's a millimetre, it's just four layers of cells thick. That's all it is between between the tissue, it's a very simple organism. It's a bit like an anemone that produces a skeleton at the bottom, so it's, it's got sort of no circulation system. Gases just dissolve across the tissues. And it's fascinating that an organism that's as simple as that can be so important in the ocean.
Daniel Tulloch
Yeah, no completely and it's something so small, you know, and sort of like, minute, can have such vast, um... It's so important, in the scale of the ocean. It's quite incredible when you think about it.
Dr Nicola Allison
So I'll show you some of these, just... So these are...
Daniel Tulloch
Wow these are amazing. So it this, is this natural coral?
Dr Nicola Allison
Yes, so this is coral that we've grown in the lab. And the pink colour is because we've dyed it. You can particularly see on this one, this animal was sitting up growing this way towards us.
Daniel Tulloch
Can I touch it?
Dr Nicola Allison
You can, I'll get you a glove. If you just put one of these on...
And when we've had it in the lab, we've put it in this dye. So don't touch the top surface, you can touch it by the sides, or that's fine.
So we put it in dye, which is this pink colour. And it records a line in the skeleton, and then we allow the coral to keep growing. So it's a way for us to be able to track how quickly the coral is growing.
Daniel Tulloch
Yeah. So it's almost like a tree, isn't it? In a sense, you know, that -
Dr Nicola Allison
Kind of that idea of tree rings, yes.
So this is a coral, that we were growing under an atmospheric carbon that would have occurred before we sort of started burning industrial carbon, when atmospheric carbon was quite a lot lower than the present day. And then something like this is a coral that was growing under the co2 atmosphere that we predict by the end of this century.
And you can kind of see, so here you can pick out these individual stain lines that show us three different periods of growth.
And in this coral, you would actually need to use a bit a microscope in order to be able to separate those lines, because they're so close together.
Daniel Tulloch
So this is current state, or this is the future?
Dr Nicola Allison
No that's the future.
Daniel Tulloch
The future, what we're going to be looking at if the things -
Dr Nicola Allison
By the end of this century.
Daniel Tulloch
Sure. Okay. So, from a personal point of view, are you concerned about - yeah? Yeah.
Dr Nicola Allison
Yeah.
Daniel Tulloch
And, yeah, it's a quite a difficult thing to talk about I suppose with the work that you do, I suppose you really see where things are going with climate change? And have you noticed, in particular, around this area, changes to the environment as well, you know, with - how long have you been here, in St Andrews?
Dr Nicola Allison
So I've been in St Andrews for 20 years. I've, I would say that in the local environment here, it's hard to pick up traces of things like ocean acidification, because it's such an extreme environment in the intertidal. So with things like, even with things like coral, you probably need to, you know, if you have things, techniques like this where you can look at the skeleton and see that growth is slowing down. If you actually go in the field, it's it's perhaps harder to observe that without actually looking through the coral skeleton. I think if you go to reef sites, and I haven't been to a reef site now for six years, because I've kind of tried to reduce my own carbon footprint.
But certainly, the sites I have visited, I've seen, I have seen a change, but I think that that's probably more driven by seawater temperature changes than by ocean acidification.
Daniel Tulloch
Really? Okay.
Dr Nicola Allison
And, so you know, ocean acidification is really pervasive, it's going to affect all of these calcareous organisms, that's an organism that produces calcium carbonate. But but for many corals, sea water temperature is probably going to kill them first.
Daniel Tulloch
And so by killing the coral, will that have a knock-on effect to the rest of the ecosystem within the sea I take it?
Dr Nicola Allison
Yes. So these, all of these organisms, not just corals but things like bivalves and sea urchins, that produce these calcium carbonate structures. That is what builds a coral reef and a coral reef often has a lot of a lot of structural diversity, because you'll have corals that will be branching, and fish can live in the branches. And you'll have corals that will be relatively flat, and you'll have corals that will be like plates. And all of those things create a range of habitats and species that are colonised by a range of organisms. So when you start to remove calcification, either through ocean acidification, or because of coral fatalities from coral bleaching, then you start to leave that strategy, you're not producing that structure. And the structure that is left is gradually broken down through storms and erosion by other organisms that tend to bore into the coral skeletons and create spaces. So you need your, your reef structure to be produced at a faster rate than it's broken down and I think that's the thing that's perhaps concerning.
Daniel Tulloch
Yeah. Concerning, right.
Dr Nicola Allison
And also, you know, that there's, there's no question that in the last sort of 56 years, there's been huge changes in some of the ecology of coral reefs and like some loss of some of the main branching specimens that made up reefs and created that habitat diversity.
Daniel Tulloch
And where abouts in Scotland are you likely to find these corals? Are they all over, or?
Dr Nicola Allison
So the corals that I'm showing you here? These are tropical corals. So a lot of what I do is in the tropics.
So if you want to find a coral in Scotland, there's one that's just inside the subtidal, so at the bottom of the low tide? But it's really tiny. And it produces a really fragile, small skeleton.
If you want to find other larger corals that then you need to go with Murray.
Go out into the colder deeper waters where we get things like the Philia, which is a coral that produces, it's a branching coral. And again, for exactly the same reason that we're concerned about corals in the tropics, we're concerned about corals in deep water, because they create that range of habitat diversity, which is important for fishing and underpins ecosystems.
Daniel Tulloch
Absolutely. Yeah. It was quite interesting. We had the, when I was, I worked on the Discovery and the James Cook, and we were launching the ROV and looking around the corals and taking samples. And it was it was quite fascinating. But also, you could sense that the scientists were quite shocked as well. And it kind of seemed a bit like a graveyard in some ways, you know, and there didn't seem to be a lot of life there. You know, there wasn't many fish, it was sort of like, 'Oh, we found fish!', but maybe it, maybe that's just normal, I don't know. Do you think the, the fishing industry has a part to play in the effects of, you know, coral groth, and you know, do you think, would you would you say that sort of has an impact at all?
Dr Nicola Allison
I think. So corals, but both deep water and tropical corals, that they are under a very wide range of pressures.
So deep water corals are perhaps more susceptible to things like ocean acidification, because deep waters are naturally more acidic than surface waters. And some some of the corals near the surface, that they've got particular pressures, that they're often close to land, so they're exposed to land runoff, which might include nutrients and other forms of pollutants. So there's a range of pressures on coral reefs, and fishing is one of those, but But it's one of several others as well.
Daniel Tulloch
Sure. And I suppose - I was up in Shetland, last month at the start of the month, speaking to Dr. Chevonne Angus, she works in the fisheries department, and, yes, she, we were talking about the effects of climate change, she sort of said that it was quite hard to pinpoint. And I suppose in the same sense, it's, it's quite hard to pinpoint exactly what's going on. But I suppose with ocean acidification, you can sort of say, 'Okay, from the start of the Industrial Revolution, this is, how things are and how things are going.', so it's maybe a bit more clear in your, in your science?
Dr Nicola Allison
I think it's, in some ways… We've got records of seawater temperature that go back further than our records of seawater pH.
But the records that we've got of seawater pH that perhaps, the earliest start probably about the 1980s or so, and, and records from that, we've now got records from around the globe. And they all show the same thing. So they all show ocean acidification. Whereas with things like seawater temperature, there are parts of the globe that are warming very rapidly, there are some parts of the globe that are going to see decreases in seawater temperature.
The thing perhaps about ocean acidification is that it's actually just about going to happen everywhere, and we can see that happening.
Daniel Tulloch
Yeah. And what causes ocean acidification exactly, is it just pollution in the air that sort of -
Dr Nicola Allison
So it's the carbon dioxide, that we're adding to the air from, from the burning of fossil fuels, and from land use changes. And that carbon dioxide dissolves in seawater. And in that process, it acts as an acid. So it makes the sea water a little bit more acidic. And crucially, that that, the fact that seawater becomes more acidic, tends to alter the amount of carbonate that occurs in seawater and carbonate is one of the components that these organisms use to build the calcium carbonate skeletons.
Daniel Tulloch
That's quite fascinating. It's wild to think I mean, the scale of the ocean that we, through our actions are having an impact on something so small and but so important as well.
Dr Nicola Allison
Yeah.
Daniel Tulloch
It's really has this sort of, it's all very connected.
Dr Nicola Allison
It is, it is, I find it quite, quite frightening.
Daniel Tulloch
It is very frightening. Yeah, yeah. It's, it's especially when you, when I see these two images, I'll take a photo of these afterwards, after the interview. Just a quick, just photo of the -
Dr Nicola Allison
Actually, my best specimens are in the museum at the moment. You know, that there was an exhibition in the museum?
It was called Dive In. So it was all about the university research, and particularly about anthropogenic stressors in the ocean. And I think it might actually even still be open this weekend. But I think it closes eventually, at the end of this week.
Daniel Tulloch
Okay, I might have a chance to have a look down there. It's worth a look. And also, I was gonna ask, is there any sort of efforts being made to help the corals grow? Or is there? Is there a way to farm coral?
Dr Nicola Allison
Yes. So there are projects, that there's quite a lot of initiatives trying to look at what we should do. So there's some initiatives, which are developing techniques, to freeze coral gametes, so that we can preserve the diversity of corals, perhaps for future generations, when, when we've addressed things like climate change and global warming. There are initiatives as well, where corals are farmed.
So fragments are grown on in relatively sheltered areas to produce larger colonies, which can then be transplanted back into areas which have become impoverished in terms of coral. So there are initiatives. There's a lot of work that's going on, perhaps looking at corals in slightly deeper waters.
Because, you know, probably the predominant stressor on surface tropical corals, is the fact that there is bleaching which is caused by increasing water temperatures. And that often occurs over periods, short periods, when surface conditions can be really calm and the surface water itself. So there's quite a lot of work that's going into looking at deeper water reefs. And if they're perhaps less susceptible to some of those pressures and what we can do to support those reefs.
Daniel Tulloch
Amazing. That's, that's a positive at least. Yeah.
Dr Nicola Allison
So there's, you know, certain certain practices can potentially help to offset ocean acidification and one of those is to grow things like algae in the water, because as part of photosynthesis, algae, like macro algae, kelp, they use up carbon dioxide so they naturally start to offset ocean acidification. Yes. There's also work that's going on to look at what can be done to remediate ocean acidification on a local scale.
But we don't fully understand the implications of that because they only photosynthesise in the light. And in the dark, they actually produce co2 along with everything else. So it's not clear how far we can go with that.
Daniel Tulloch
Okay. And it's interesting, talking about algae, I don't know if this is a correlation or anything. But again, when I was in Shetland, I was speaking to some people that worked in the fisheries industry. And they were sort of saying, you know, algae blooms are also on the rise. Does that have an effect at all on coral? Do you think? Does that have any sort of?
Dr Nicola Allison
So, I don't know. I think you know, so, nutrient inputs into reefs can be significant, can be a significant pressure at some locations, because they either cause an algal bloom, or they support the growth of more algae which can then potentially overgrow the coral.
But I didn't know about sort of like short term algal blooms.
Daniel Tulloch
Sure. Yeah. Because I sorry, I'm not a scientist, so it's quite...(both laugh). It's quite fascinating this! So I'll probably have to stop the interview there. So that I'm not late from the next interview, but thank you so much for your time, that's been really good.
Dr Nicola Allison
Okay, that's alright, gosh you're really getting around today!