Bernardo Da Gama
- First meeting
- 2011, May 17th
- Last update
- March 2017
- algal chemical ecology, chemical defense of marine macroalgae, antifouling compounds, antioxydant compounds
“One would think of macroalgae as very sessile organisms, standing attached to the bottom and doing nothing. They seem to be quiet but this is not true: there is a lot of activity happening there for defending against herbivores, epibionts, competitors, other algae... Algae engage in producing and releasing very different compounds. What happens there is actually a chemical war!“
Welcome to the Phycological Defense Department. In Brazil, under the cover of marine biologist, Bernardo Da Gama leads investigation on the war happening underwater. We are talking here about a chemical war: it involves algae and their numerous enemies eager to eat or invade them! Algae implement strategies for defending themselves against these organisms. Meet Bernardo and discover more about algal chemical ecology.
I am Bernardo Da Gama, professor and researcher at the department of Marine biology of the Institute of Biology of Universidade Federal Fluminense which is located in Niterói, Rio de Janeiro, Brazil. I work in the field of algal chemical ecology and biofouling as well.
What is algal chemical ecology?
Well, one would think of macroalgae as very sessile organisms, standing attached to the bottom and doing nothing. They seem to be quiet but this is not true: there is a lot of activity happening there for defending against herbivores, epibionts, competitors, other algae… Algae engage in producing and releasing very different compounds. What happens there is actually a chemical war!
Algae use chemicals for inhibiting other organisms, that’s why it is so interesting to study the chemical ecology of algae. From all the marine organisms - of course corals and sponges are also very interesting from this point of view - but algae they are much more. We would expect them to be simple but yet they are very good chemists and produce lots of different compounds. For example, Laurencia, which is one genus of red algae, produces more than 500 different compounds, so they are really really really good chemists.
Why do they produce so many compounds? That is what we want to discover!
In our laboratory, at the moment we have several different projects with macroalgae.
Defense compounds from macroalgae
- Defense against herbivores and antioxidant activities1
We study the defense of marine macroalgae against herbivores, against consumers like for example sea urchins, fishes, crabs etc. What do algae do to defend themselves against their predators? The algae produce a lot of compounds, brown algae produce polyphenolics, red algae produce halogenated compounds, green algae produce diverse arrays of compounds but not halogenated and not polyphenolics. Some of these compounds have antioxidant activities. We try to investigate the ecological roles of these compounds in the defense of algae against consumers.
- Defense of against epibionts2 and antifouling activities
We also look for chemical defenses of macroalgae, not focused on consumption, more focused on how the algae defend themselves against the epibionts, i.e. against all the organisms that try to settle, which are looking for space to settle. These organisms look for somewhere, a good substratum, to settle and then they try to attach to the algae. Over millions of years, algae have developed some chemical defenses that they use as antifouling compounds.
This is very interesting and has a lot of industrial applications since biofouling is also a problem for ships, oils platforms and all the maritime commerce. This has a lot of applications but basically first we are interested in how the algae defend themselves against epibionts. Applications come on a second step and depend on a lot of others fields such as chemical synthesis of compounds (we don’t work in this field).
- Distribution of defense compounds
We have been working in macroalgal defense against fouling for more than a decade now. We are still working on it and are now trying to get a large picture of what is going on.
We study the location of these defenses in the different part of the thalli3. Algae are not all equal, some algae are just you know leaf-like and all the thalli produce everything. Other algae are more specialized, they have like floating parts, reproductive parts, light catching parts, leaf-like parts,… We are interested in knowing how these different parts of the thalli defend against consumers and fouling. This is something that is ongoing now and for the future we expect to work more in that field and like others applications, like antioxidant activities.
Also are there latitudinal differences? The Brazilian coast is very interesting in this sense because it is very large. It goes all the way, almost to Antarctica. We also have a base in Antarctica. We want to see if the defenses are more active in the tropical part of the coast than in subtropical or the cold part. Theoretically the tropical algae should be more defended but we are not sure if this is true.
We are also interested in knowing which type of algae - red, brown or green - has more antifouling defense. It is leaning towards that, at least in the South West of Atlantic, the red algae are the best defended. We are still getting more datas and doing some correlations. We expect to have very nice results in the future.
We also lead some macroalgal ecology studies dealing with factors such as nutrients or light and how those affect photosynthesis or the production of chemicals compounds like the defense ones.
Examples of projects:
- Algal ecophysiology in the context of global change
This is an international project coordinated by Kiel in Germany. In this project we are mainly interested in how algae respond to fluctuating unpredictable light levels. With global change, we expect some weather changes in the future. As algae depend so much of light, it is expected that they should respond somehow to the changes in the weather conditions. We are interested in knowing how tropical algae will respond to the fluctuating unpredictable light changes that will come with the global change (which perhaps already came). In this way, we plan to study the defense compounds and the storage compounds for example as well.
If an alga stays a long time without light, it will probably have to rely on reserves. Usually tropical algae do not have large reserves because they live in a predictable environment where light is available year round. We don’t know what is going to happen if the weather change becomes true. This is on what we are trying to focus this project now. It is a small project, but focusing on a very important topic.
- Floating algae
We have projects starting with floating algae which is a topic that have never been studied. In the South Atlantic and we don’t have large kelp but we have floating algae like Sargassum for example.
Applications of algal chemical ecology
This field of research in algal chemical ecology can lead to several applications.
In our group, we have people studying applications of chemicals such as drugs. There is a potential for new drugs, for example, against HIV and other viruses or against several kind of diseases. We don’t specifically focus.
In my group, we work with antifouling compounds and antioxidant compounds. Of course, a lot of this work is done by collaboration with other institutes, including in France, in UK, and other countries.
We see a lot of other potential applications in the future.
By learning more about antioxidants, we study and expand the scope of algae uses as food.
In the same manner you can consume entire plants, you also can consume all the algae that are not traditionally eaten.
In Latin America, in Brazil, the tradition of eating algae is not so profound but once that people realize the benefits derived from algae consumption, it may lead to a new health culture for example.
In the field of antifouling, this would be more to industrial applications. It is very very large and interesting field: it concerns navigation and human presence in the sea, be it by means of boats, off board, oil platforms, oil exploration in the sea,… Everything related to that involves biofouling and huge economical and industrial applications.
And of course it also have to do with preventing the use of new toxic compounds in the sea as it happens in the past as the use of TBT4 and others compounds which were very toxic. Now people are looking to marine chemical ecology for new alternatives to toxic compounds: those are basically non-based on heavy metals that have now been banned all over the world. In many places, people are starting to work with marine natural products as antifouling compounds. The main focus is clearly in the algae because of their such good chemistry talents.
Currently, we work on these applications. Others will probably rise in the future.
From the alga to the new antifouling paint
Regarding antifouling research, it is interesting to know a little bit more about how it works. Let’s think of something settling in the sea, for example a larva of barnacle: when it starts, it first feeds on plankton and looks after the light. Suddenly it becomes a competent larva and then it searches for a nice place to settle. Then it starts to look for certain chemical compounds, substratum, rugosity, chemical composition of the substratum… And then it is exactly where the chemical ecology happens: if one alga produces something which inhibits the larva, this larva will swim away from it. That is an antifouling activity.
In our laboratory, we use laboratory tests and fields tests to look for new antifouling compounds. In the laboratory, we use juvenile mussels: ther are very young and tiny mussels. Juvenile mussels have a very interesting property: even after the larva becomes a juvenile, they still keep the ability to response to chemicals. They also have something that barnacles don’t do: they can detach and attach to a new substratum. Once a molecule works, if it is really promising, then we try to get more materials and to test in the field.
In the field, there are not only mussels and barnacles, there will be like 100 different species that can settle on a substratum. The fields experiment are really important because it is not like testing a new antibiotic for which you know the identity of the target specie, the pathogen. For an antifouling compounds, you must target a lot of species. It must have a wide spectrum of activity and, at the same time, it must not have a toxic activity. If it is very toxic, it makes no sense to try to introduce a new pollutant in the sea. So during the tests, we also make an approximation of a possible toxicity assessment. If a compound is really effective as an antifouling but is really toxic, we don’t follow up with this compound because this is not going to give a good result and be environmentally friendly. We try to focus on compounds that don’t kill the organism but repel them. So that is the main focus on our research in antifouling compounds.
From the molecule to the marketed product
It is not fast to get to the compound, identify it and reattribute the antifouling activity to the compound. Once we discover and identify a new antifouling compound, then the next steps can start. It is not easy and not fast as well.
Once you have this result, then you have first to protect it because it is a discovery with potential commercial application, so you have to make a patent. This is very slow and time consuming. It involves lots of paperwork.
- Chemical synthesis
Even if you take all the algae from the sea, you won’t be able to paint a single large tanker. It would be not possible to paint a large boat for example with something extracted from living biomass. Biomass is really not enough, especially when we are talking about tropical algae. We could think about cultivating algae at very large scale but the concentration of the compound is really low. So you have to get in contact with a chemical laboratory for being able to produce the compound through chemical synthesis.
- Material technology
Then you must be able to put the compound in a paint matrix. This involves the field of material technology and paint technology. The paint must be able to cope with the new compound, i.e. to release it in a very slow manner. The compound must not interfere with the property of the paint like the color, or the adhesion to the ship for example.
That are the steps following our researches, from the alga to the final product in a shelf somewhere. Of course we don’t do it all: we don’t do the chemical synthesis but we can test the final paint in our lab and in the field for example. Definitely we can not extract everything from the algae, we must use it as a template for looking for new compounds through chemical synthesis, biotechnology or bioengineering. New bacteria for producing the compound would be also an alternative of course but this is not very easy. This takes 5 to 10 years of research to get to the final product.
For example, during my PhD, we discovered a molecule which was not new but was never used with this application. This compound is elatol. We did a patent. In Brazil, it take years for patents to come out and they are not really valid outside the country. This compound has been produced through chemical synthesis in 2008 if I am not wrong, but it is still not introduced in these applications. Yet, we did discover something very interesting, promising and we still have not found anything so active as elatol. So far it has not led to a real application. This is how things work. Maybe in 10 years someone will produce it somewhere in a more economically viable way and then it will start using it as an antifouling compound or it will show up to be very toxic, we don’t know. There is a lot of years of research ahead to real applications.
About innovations in phycology
In the field of phycology, I think we have several very interesting new applications being developed in different skills, in different part of the world. Maybe the most interesting topics are of course the IMTA (Integrated MultiTrophic Aquaculture) and bioremediation.
I still think that traditional uses like algae as a source of food or a source of nutrition: not only the main dish but also as an additional source of nutrition. This is probably where the major applications and more simple applications lies for the future of phycology.
Of course, many cultures already use algae as food and nutritional complements. But still in many cultures, we don’t use it as food. It is a basic primary producer: it can be produced in large amounts without large energetic or environmental costs. Maybe the main global use of algae should be as food and as a nutrient supplier. Algae are known to be very rich in some nutrients and some vitamins. I really think that in many countries the quality of life could be much better if algae were used as a food source.
Of course, as many phycologists, when we think of aquaculture, we are also worried about the development of new commercial applications which could bring for example algal species that become a bioinvasion. This is a major concern to keep the biodiversity as it is in several places and to avoid to make new introductions. It must be avoided, it must studied, but it can not be 100% sure anytime you bring another specie to culture it somewhere. But that has happened as well in the rest of the environment: many food sources that are now widespread all over the world, were initially introduced in many places. It must be controlled but it is something that perhaps also should be done.
I think that maybe algae have been still underestimated as a source of basic studies and applied studies as well. I think that more investment is needed in this field. Making the knowledge about marine algae available to the general public is very needed because it is from the general public that come the pressure for the politicians to invest more money in research, in basic or applied research in the field of phycology. This is something that we really need for the future.
Well, how I became an Algonaut? I don’t know for sure, but the thing is that I came from a Portuguese family, I was born in Portugal. Portugal is very focused on the sea so I always had this passion for the sea, so I became a marine biologist. Then I did my master and my PhD also in Marine Biology and at a certain point I started working mainly with algae but not only with algae.
I don’t know, maybe the interest in algae came from the interest in chemical ecology. I think that my interest in algae came from the interest in applications of algae. Since I have started my marine biology course, I have always been interested in applications. I was always more interested in practical studies than in very basic research. Then I went to the algae because they really seem to be the most interesting marine organisms from the point of view of the potential applications. It is possible to culture them relatively easily in the field and also in the laboratory.
So I think I became an Algonaut because algae are really interesting from several points of view. From the pure ecological point of view, they are the basis of the benthic food web and they also interact with pelagic foodweb. They are really interesting organisms. Of course, even today, I don’t work only with algae but with the benthic community. For the chemical ecology, we work with algae, macroalgae indeed, not the tiny microalgae. I still keep thinking that the algae may have so many things to be studied that they will remain the focus of many fields of research, not only phycology for the next 20-30 years perhaps.
Message for the Youth
Anne-Gaëlle: What would you say to an 8 year old child who is affected by the prospect of a future with climate change, pollutions, biodiversity loss, energy crisis and overpopulation?
So, about the future… you have to be optimistic because of course we are living in a difficult moment in our planet. There are not only starvings, pollutions, habitat destruction, diseases and many others things, there are also have wars, boundaries being closed, we have a difficult moment. But in the future, I think that we are going in the right way, at least a part of the world is going in the right direction. As a researcher of course I believe in the future otherwise it would make no sense to do any applied research. Many solutions may come and have been coming from science over the last centuries, over the last decades: light, heating, cooling hot places like Brazil,… it is coming from science. Environmental solutions, food production solutions may come not only from algae of course but from aquaculture and many other sources as well.
Of course we will have to change many things in the current mentality, in the way we spend energy, in the way we waste food, in our life styles. Our life styles are not equal. The life style of an American is not the lifestyle of an Indian person and so are the energy consumption patterns, the food consumption patterns, and also the diseases and the environmental problems that arise from these patterns. They will have to change. We will have to change to a more sustainable way in the future.
Science is replying one by one to many questions and sometimes making accidental discoveries that look useless at the first moment. Then later they become very important solutions. It has been like that with television, with electric light, and with computer also. And now we rely on those inventions. So in the same manner, for finding a sustainable future, a sustainable way of life, we need to look into science, rise the public awareness about science, so that the general public can also make changes and make pressures on the politicians and decision-makers to invest more in education and science. I think that the future relies on large investment in education and science, and everything else will become better as a consequence of that.
For more information
Bernardo Da Gama on Research Gate
Jacqueline Algane talks her meeting with Bernardo on the chapter Fouling
Interview of Claire Hellio (in French)
Interview of Erwan Plouguerne (in French)
Antioxydant activity: When a cell is exposed to a stress (such as UV, toxic compounds, etc.), this stress can lead to the formation of free radicals: this is called oxidative stress. This oxidative stress is responsible for cell deterioration and can result in cell death. For coping with that, algae have defense mechanisms and adaptations: they secrete anti-oxidant substances that prevent deterioration due to oxidative stress. Algae are a good source of natural antioxidant substances and therefore there is a lot of interest in these organisms. ↩
Thalli is the plural of thallus and is a word used for naming the bodies of some non-mobile organisms such as algae, fungi, lichens. Jacqueline Algane tells more about her understanding of thalli! See Thaali Tali ↩
An epibiont is an organism which lives on the surface of another organism. When the settlement and growth of an organism occurs on the surface of a plant, it is an epiphyte. While this biological interaction is supposed to be harmless and without benefits for the host (at the difference of parasitism), it can have indirect effects and impact nutrient uptake or light access for example. ↩
TBT: Tributyltin. For 40 years and until 2008, antifouling paints used against colonization by organisms on ships or marine infrastructure were formulated with tributyltin (TBT), an heavy metal. It was very active and efficient for 8 to 10 years. It was also extremely toxic! Researchers have shown that tin-based paints were linked to malformations of the oyster shell and an endocrine disruptor for marine snails, such as the dog whelk (Nucella lapillus). TBT compounds are banned and are included in the Rotterdam Convention and have been banned by the International Convention on the Control of Harmful Anti-fouling Systems on Ships of the International Maritime Organization. More information for example here: Wikipedia page on TBT. ↩