Dr Nicole Webster, marine scientist

Dr Nicole Webster

Marine scientist

Nicole Webster was born in Ormskirk, UK in 1973. Webster completed a Bachelor of Science (Hons) in 1995 and a PhD in 2001, both at James Cook University in Queensland. Her PhD thesis investigated the microbial ecology of a Great Barrier Reef sponge, focusing on the stability of the symbiotic associations over different areas and under different stresses. Webster’s first postdoctoral fellowship was with the Australian Institute of Marine Science (AIMS) in 2001. Webster was subsequently awarded a post-doctoral fellowship from the University of Canterbury and Gateway Antarctica (2001-05). This research focused on utilising microbial communities as indicators for human-induced stress in the Antarctic marine environment. In 2006, Webster accepted a position as research scientist at AIMS where she continues to study microbial-sponge symbiosis as a sensitive marine model of environmental stress.

 

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Interviewed by Dr Cecily Oakley 6 May 2010

Contents


My name is Cecily Oakley and I am here at the Australian Academy of Science to talk to marine scientist Dr Nicole Webster. Welcome, Nicole, and congratulations on your 2010 Dorothy Hill Medal.

Thank you.


Playing in rockpools

Let’s start at the beginning. Where and when were you born?

I was born in England, in a little town called Ormskirk, back in 1973. But I only lived in England for about 12 months and have been in Australia ever since; my father is English but my mother is Australian.

When did you first get interested in science?

I don’t know. I think I was always interested in science, even as a little child. I did spend a lot of time at the beach when I was younger—sort of 12, 13, 14 —and I used to love exploring the rockpools down at Wollongong beach and finding all the things that lived in the rockpools. I did have a very good science teacher in years 11 and 12 and I really loved biology at that point. Physics scared me, but I was definitely a lot more passionate about biological science than anything else.

Were there any teachers or other role models that inspired you?

Not really; not at a young age. I definitely wanted to move north; I wanted to be near the coral reef. So that was one of the major factors in deciding to study marine science and move up to Townsville.

That’s what you studied in your bachelor’s degree?

That’s right, yes. I moved up to Townsville and undertook an undergraduate degree; it was actually in biological sciences with a major in marine biology.

Breadth of marine science

Perhaps you can explain for us what a marine scientist does.

I think that’s a really difficult question to answer because there’s such a diversity of people working in marine science. I’m actually a marine microbiologist, so I work on the very tiny things that we can’t even see. Then there are people who work on all the different organisms that live in the ocean; they are biological scientists. But, within marine science, there are also people that work on modelling and oceanography, currents, nutrients and things like that as well. So I think you could basically work on just about anything within the marine environment and still be considered a marine scientist.

It’s very diverse.

It is incredibly diverse, yes, but that’s part of what makes it so much fun.

Sponge symbiosis stressors

For your PhD thesis, you looked at the symbiosis between Great Barrier Reef sponges and bacteria, and how that symbiosis changed with stress. Can you explain for us what you mean by ‘symbiosis’?

There are multiple definitions for ‘symbiosis’, in its loosest possible definition symbiosis is a consistent association between two different organisms. That doesn’t have to imply any sort of benefit to either partner. When people think of symbiosis, they mostly think its two things living in association with each other where both of the partners benefit. For example, if there is a microbe living inside a sponge or a coral, the microbe gets some sort of protection from the surrounding environment and the coral gets some sort of nutrition from the microbe. When most people talk about symbiosis, that is the sort of relationship that they’re thinking of.

But the one that you’re talking about is coexisting without necessarily any detriment?

In that sense, pathogenesis or disease is also considered symbiosis, in the loosest possible definition. With the sponges that I work on now, I’m looking at the whole cross-section: all the microbes that are in there, the aspects of disease and the consistency of the relationship. I think that is probably how we define symbiosis: how stable that relationship is. So, if you change the environmental conditions, or look at it over a really broad geographic range, and find that relationship is identical over those sorts of gradients, to me that implies a really consistent relationship and a true symbiosis.

With the sponge microbiology that we do, it has taken a very long time to try to describe what microbes are present in sponges and how consistent the relationships are, and it is only now that we are really starting to look at what function the microbes might have. For example, whether they provide the sponge with nutrition, structural rigidity or maybe even metabolising some of the waste compounds from the sponge. There are many possible functions that could be happening, but we’re really only on the tip of the iceberg of exploring those now.

Is a sponge a plant or an animal?

In fact, I was just asked that question a few minutes ago by one of the scientists downstairs. Right up until the 1700s, sponges were considered plants because you were only an animal if you were sentient and were you capable of muscular response and movement. In about the mid­1700s, a couple of scientists contradicted that and described sponges as animals. They definitely are animals, but they are the lowest of the metazoa, so they’re the most ancient of the multicellular organisms.

What did you discover in your PhD studies? How did the relationship between microbes and sponges change?

When I started my PhD, it was really interesting. Sponges at that time were considered quite sexy research topics because there was a lot of research happening around drug discovery. And sponges produce almost all of the compounds from the marine environment that have made it into clinical trials. They produce a wide range of anticancer compounds, anti-inflammatory compounds and anti-tumour compounds. Part of the reason for this is because they are sessile—they just sit on the bottom; they can’t move and they can’t escape—so, as a natural deterrent, they produce these really nasty compounds. For a sponge researcher, that was fantastic because all of a sudden drug companies were investing large amounts of money into sponge research.

I was not so interested in the application of the chemistry; what I really wanted to know was what happens with the relationship. I was more interested in looking at the symbiosis, but I was able to use some of those funds. I looked at one of the sponges that produce some anticancer compounds and I looked at what microbes were inside it. This research was based on the idea that maybe some of the microbes were producing the interesting drug compounds. When I started looking, I found that the microbial associations were really broad and that they were really consistent over a really broad range. I looked right from the top of the Great Barrier Reef almost towards the bottom of the Great Barrier Reef and I saw the same associations over that massive geographical gradient. That made me think that there was something really specific about the partnership between the sponge and the microbe.

In the latter parts of my PhD, I wanted to look at how environmental stress might affect the relationship. In the last six months of my PhD I started a fairly large experiment that exposed the sponges to heavy metals—something that may happen in the environment from industry—and had a look at what happened to the relationship. What I found then, directed all of my future research. I found from that project that the symbiotic partnership—the relationship between the microbes and the sponges—actually broke down just before we saw signs of stress in the sponge. So that gave me an indication that maybe they’re very sensitive indicators for stress and maybe, if we can detect the stress prior to seeing the signs of stress in the animal itself, we then have a better opportunity to conserve them.

What sorts of experiments did you do?

One of the amazing things about sponges that almost nobody knows is that all of the cells in a sponge are totipotent, which means that they can differentiate into any other cell type. With a skin cell or what we call a ‘pinacoderm cell’ in the sponge—if you cut that sponge, other cells, cells that might be involved in water flow or nutrition, can actually migrate to the site where the sponge has been damaged and can turn into new skin cells. Basically, they are effectively stem cells. That means that we can take one sponge and chop it up into 100 little mini-sponges and leave them out on the reef to heal for a month or so, while they form a new skin surface. Then we can bring them back into the lab and we’ve got a whole heap of replicates that we can use that are genetically identical, and we can form those sorts of experiments there. Then we keep them in aquaria and use a dosing facility; so we have a header tank with the contaminants or whatever and we just drip them into the tanks.

How do you go about measuring the microbial population of a sponge?

That’s the thing that has changed most since I started my research career. When I first started working on sponges, molecular techniques were still just evolving. A lot of people, when they looked at microbes, would get a piece of sponge, grind it up, stick it on a plate and see what grew. The research that I started doing in my PhD showed that we culture about 0.1 per cent of the bacteria in a sponge, so we were not seeing anything. Also, that 0.1 one per cent doesn’t necessarily reflect the most abundant bacteria inside the sponge; they’re just ones that are amenable to cultivation. Then we realised that we have to start applying molecular techniques to see what microbes were in the sponge.

Microbes have a very good phylogenetic marker gene, which is called the 16S ribosomal RNA (rRNA) gene, and that is highly conserved. It has regions that are really conserved and regions that are really variable within the one gene, making it a good marker for us to be able to assign a phylogeny to different microbes. With the sponges, we would take a sponge, extract all of the microbial DNA from it, clone that microbial DNA and then sequence this 16S rRNA gene to try to identify what the microbes were. We were looking at it basically from the DNA approach rather than a cultivation approach.

Antarctic pollution

After your PhD, where did you go next?

The very last thing I did in my PhD was a heavy metal stress experiment that suggested that sponge symbiosis might be a sensitive indicator for stress, and that helped me design my postdoc project. I combined that with the fact that I’d always been totally passionate about the Antarctic environment, and sponges are one of the dominant organisms down in Antarctica. So I tried to link all of those threads together and I applied for a postdoctoral fellowship with the New Zealand government to go down to Antarctica and try to use the sponge microbial associations as a sensitive indicator for stress coming from the Antarctic research bases.

Around the New Zealand base down in Antarctica, there’s some localised impact; there’s a sewage treatment and things like that. But, just around the corner from that, is McMurdo Station, which is the American base. McMurdo Station used to discharge all of its waste, including all of the heavy metals and sewage. Everything at the end of a field season—this is in the early days of Antarctic research—would be shovelled out onto the bay where ice was and then, at the end of summer, the ice would melt and everything would fall through. So that’s actually one of the most contaminated bays in the world. People think that Antarctica is a really pristine environment—and, in general, it is—but around that research base is a really contaminated site, but it is dominated by sponges. We wanted to look at environments where there had been no previous human impact—where people had never been—and very close by was one of the most contaminated bays in the world. So we looked at the microbial associations in the sponges over those sites.

Had anything similar been done before? Had anyone looked at the impact of people in Antarctica?

There had been a lot of research into human impact. In fact, I think a lot of that research guided very strict environmental protocols that were developed in subsequent Antarctic research years. Most of the research looked at things like the macroorganisms, because they are the things that are most visible—for example whether things could recruit on contaminated sediments etc. So, there was a baseline level of knowledge about Antarctic contamination.

What did the sponges tell you about the impact of people?

Contrary to my big scare campaign, the relationships were incredibly conserved and had not been impacted by the sites. Regarding the level of contamination—even though it was off the scale for things like heavy metals, hydrocarbons and TBT from the antifoulant paint of the icebreakers that go down there—the microbial associations in the sponges were completely identical to regions that had never seen human populations.

What was it like conducting research down in Antarctica?

Cold, incredibly cold. I came from Townsville, which was sort of plus-35oC to Antarctica, which was about minus-35oC. Learning to dive down in Antarctica was a major thing for me. Even though you wear a drysuit, and underneath your drysuit you have something called a teddy bear suit, which is this warm, fluffy thing, it was incredibly cold. The water there is minus two. Because of the salt content in the water, the water doesn’t freeze at zero; it freezes at minus two, so you are almost diving in a slurry. But, once you were under the ice, it was so incredible. What we saw was so amazing that you almost forgot about the cold; it was incredible. We saw sea spiders the size of dinner plates, jellyfish 40 metres long and the most amazingly coloured sponges and soft corals; it was incredible.

It sounds fantastic. I always associated things like sponges and corals with tropical regions and not really Antarctica.

Yes. Well, that’s the amazing thing about sponges and why they really need to be the focus of more research effort on environmental stress because, on coral reefs, corals may be the dominant fauna but, at depths below 15 meters or in the regions in-between reefs or down in the poles, sponges are the dominant fauna. Really, very little research effort has gone into sponges relative to corals.

Getting microbes on the agenda

How can scientists use your discovery of the relationship between sponges and microbes to keep the reef healthy?

I think one of the really important things that I’ve been trying to push for the last few years is even to get microbes on the agenda of people who are managers and policymakers. For most people it is ‘out of sight, out of mind’. They can’t see the microbes, so they don’t realise how important they are. I really hope that my research has tried to make that a little more visible—that we can’t not consider microbes with environmental stress. We talk about climate change and stressors such as climate change and what impact they are going to have, but microbes make up the majority of the marine biodiversity and the majority of the marine biomass and, if you’re not considering them in your assessments of how things are going be impacted by climate change, you’re missing a really big chunk of the information.

Microbes also respond very rapidly to changing environmental conditions. They can turn over a lot faster and we can have a generation of a microbe within a day, so they’re going to be the first things to change when conditions change. They’re going to be a much more sensitive indicator than things that are much longer lived and that may take a long time to start showing environmental effects. So I think that is probably—I hope—the major contribution that my research has made.

Why do sponges have so much bacteria?

You mentioned in your talk today some ideas about why you think the microbes might be present in the sponges, ie. what their function is in terms of the ecosystem. Perhaps you would like to comment on that.

There are a couple of different symbiotic functions that have been suggested for sponges. One is nutrition because normally, when there is a symbiosis—whether it is in mammals, plants or whatever—the symbiosis is generally based around some sort of carbon transfer between the symbiont and the host; there’s a lot of suggestion about that in sponges as well. We now know that some of these microbes produce fairly potent antimicrobial compounds. So there may be a role in some sort of defence that the microbes are actually affording: by producing antimicrobial compounds, they’re stopping the overgrowth of other microbes that may be pathogenic for the sponge. Quite often, they are there in very high density. Say, 40 per cent of the biomass of the sponge can be microbial, that means that almost half of the material of the organism is microbes. With that density of microbes inside the sponge, they can contribute to the structural rigidity of the sponge.


I think all of these scenarios are highly feasible but they have very little empirical data to back them up at this stage, because it’s very early research. But one of the other things that has been suggested is that they may eliminate the waste compounds that are produced by the sponge. So they may be able to turn over some of the compounds that may be toxic, if they build up inside the sponge—like ammonium and such things.

Current research

What are you working on now?

At the moment I’m still working on temperature stress. In the past I have looked at temperature stress and how that affects the adult and how the symbiosis fails at a threshold temperature of about 33oC. One of the things that I want to look at now is whether the larvae of the sponge are similarly sensitive or whether they’re a bit more resilient to changes in environmental conditions. I’m spending a lot of time working on sponge larvae. I also have a couple of PhD students, one of whom will be working on nutrient stress in sponges. For example, when we get a lot of run-off during flood periods from agricultural areas and we get spikes in nitrate and things like that, how that affects the symbiosis. I have another PhD student who’s doing some really amazing work on sponge disease on the Great Barrier Reef and the likely impacts of that.

Do you have other people that you work with in your experiments?

I do. I collaborate fairly widely. I work at the Australian Institute of Marine Science, which is a fantastic institute and now does have a fairly decent base in microbiology. But, up until the last couple of years, I was one of the only microbiologists at AIMS. So, to be able to stay at the forefront of your field, you really did have to form international collaborations. I do have a lot of really good international collaborators and I also collaborate with a couple of people down at the University of New South Wales.

Looking to the future

Where do you see yourself in 10 years time?

That was the question that I most feared, because I think that’s the hardest to answer. I find it really difficult to maintain a career in science, partly because the really enjoyable aspects of science are the sorts of things that you do in your postdoc years and maybe one or two years out of your postdoc. When you’re still doing the fieldwork, you’re in the laboratory, you’re doing the discovery and it’s so exciting. Then, as you develop your career in science, you have to pull back from that a little bit, because you just don’t have the time to do it. I struggle to want to go too much further up and away from the actual science that’s happening on the bench. So I’ve tried not to think too deeply about where I’m going to be in 10 years time, because I hope that I’m still very actively engaged in the actual experimental work. Hopefully, I’ll have a little more support in the lab and a couple of postdocs to help with some PhD students.

I’m very lucky that my husband also works in science. We both have permanent jobs in science, and I think that’s incredibly rare. We both do what we are passionate about doing and we have a very young family. So I think we’ll probably still be in Townsville in 10 years time surviving and trying to juggle.

Advice and the challenges of being a Scientist Mum

Do you have any interests outside of science?


I have three children—six, three and 18 months—so I don’t have any time for other interests. Actually, that’s not true, as I’m very passionate about science education in young people, so I do take a very active role in science in schools programs, visiting my son’s school and helping with the science program and trying to engage young children in science.

Do you have any advice for budding scientists?

I did think about that question as well. In fact, I spoke to a scientist about that today after my talk. We agreed that, if there was one piece of advice for somebody starting a career in science, it’s to have a very thick skin. I think, in the scientific process, it’s easy to be criticised, although that doesn’t necessarily mean that you are wrong. I think, if you are doing good science and you know that you are doing good science, stick with it, have a thick skin and try to avoid being liked by everyone, because it probably won’t happen. You’ve just got to have faith in your own scientific skills and your ability—and be passionate, because it makes all the difference. If you love what you are doing, if you love the experiments that you are doing, it is so much easier to ride the waves. If you’re only half-hearted about a project, probably leave it be.

Very sage advice. As a woman in science, what do you think the challenges are in establishing a career?

I think that women in science in the past probably had very different challenges to what they have now. For me, when I try to think about the challenges that I have in science, they revolve around parenting more so than in being a woman, just trying to do the juggle. This is one of the reasons that in my talk today the last slide, the acknowledgement slide, actually had photos of my children on it, because I really do believe that you need support from family. In science, the time that you give to science, if you’ve got a young family, you take away from them. So there’s this constant balance. It’s very easy to get caught up in this guilt cycle where, if you’re doing science, you’re guilty that you’re not with your children; and, if you’re with your children, you’re guilty that you’re not doing science. You’ve just got to say: ‘Look, I’m doing the best I can and I’m trying to make a difference and be happy about it.’ Yes, I think that’s the real struggle with being a young parent and a woman in science.

Finally, what skills do you think you need in science today?

Tenacity would have to be a big one and an analytical mind, questioning everything and being able to accept that you’re wrong; not being so fixated on an idea and so convinced of its outcome that you can’t take a step back. I think that’s probably one of the biggest things. Keep a very open mind.

Thank you very much, Nicole, for taking the time to speak to us. It’s been a pleasure.

It was a pleasure; thank you.

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