How an underwater hotel is helping to identify marine biodiversity hotspots
A new paper published in Nature Communications has utilised EMBRC’s EMO BON network to make an important discovery about marine biodiversity richness. In this Q&A Matthias Obst, University of Gothenburg explains the significance of this new publication.
What question did you want to answer?
A longstanding question in marine biology is where biodiversity richness comes from. What drives species diversity in the ocean? It’s a complex question because there are many factors affecting how and why a species appears and aggregates in marine habitats.
Historically, scientists observed a latitudinal gradient of species richness, which means that habitats typically become more species rich the closer they are located to the equator. One popular explanation for this was that the observed patterns may be driven by temperature and food – in other words, habitats with warm water and a lot of food would support more species. However, there are many exceptions to this rule, especially when looking at the entire range of ecosystems from the poles to the equator; eventually, preventing this hypothesis from being fully established.
In the ocean, the primary production of algae in the water is a good measure of the energy that’s available for other species. There’s been an ongoing debate about how the combinations of temperature and energy availability could be measured and this is something we wanted to explore further.
How did you undertake your research?
We used Autonomous Reef Monitoring Systems (ARMS). When a researcher investigates soft sediment, such as mud and sand, they would simply bring samples up to the surface to analyse. That’s not possible with the hard bottom seafloor made up of rocks and boulders. Here, researchers put down so-called passive monitoring systems (ARMS) on the seafloor that they can bring back up at any time for further investigation.
ARMS are like small hotels with nine floors. They have intersections between some of the plates that create micro habitats where larvae can settle, and creatures can creep in and are protected from grazing. You put this little hotel in the ocean, wait for everyone to move in, and then bring it up. Then you can easily disassemble it to take photos and genetic samples. The data are completely comparable across the globe. Deploying these structures again and again helps us monitor the changes in biodiversity across different ecosystems over time.
What were the most significant findings?
This paper finally nails down the relationship between the critical environmental factors and the species diversity they support. Our study strongly supported the hypothesis that continuity of food supplies support biodiversity rich habitats. For example, when you have an ecosystem producing food all year round which then, on top of that, has high levels of food, that's where you have biodiversity hotspots.
It’s not the temperature, per se, and it’s not the energy, per se, but it’s the seasonality of these factors. For example, in an Arctic ecosystem, a lot of energy appears for a very short time. That cannot drive biodiversity richness because the blasts of energy are too short for species to utilise. There’s a lot of competition for it and then it's gone.
We’ve found it is much more important that resources are evenly available across the year. Ecosystems in the tropics have a much more flat distribution of energy. The amount of energy available and how much it changes through the year is key to this species richness.
Why is it important to understand this?
We’re living in a time when we need to identify biodiversity hotspots so we can protect them or engineer the right conditions for species rich communities.
Now, we know the conditions needed to build ecosystems that support many species. It also gives us the criteria for choosing which areas of the ocean should be protected and allows us to identify which zones should be prioritised for protection.
How did EMBRC’s services support this paper?
EMBRC marine stations provided vital diving services. When you sample using ARMS plates, you depend upon divers at marine stations who know the habitats well and use their expertise to make sure the sampling is successful: that the plates aren’t put in the wrong place or washed away, for example.
EMBRC’s EMO BON observatories helped us identify the pattern between ecosystems across the globe because they ensured samples were collected and analysed in a standardised way.
That was not possible before EMO BON because every time someone takes samples, they do it in a different way or focus on a different species. When you assemble data that has been collected for fish vs for mollusks, it cannot be compared because it’s skewed towards a certain taxonomic or ecological group.
The EMO BON network is standardised and reproducible and so removes any investigator’s bias. Sequencing machines and data algorithms work the same way on every sample to produce comparable results. This allows us to measure biodiversity in a consistent way and gives us a much clearer pattern.
By providing a network of marine stations through its infrastructure, EMBRC has enabled us to truly monitor species diversity on a global level.
What are the next steps of this project?
We’re now in the data phase of this project. Having proved the concept, we’re now producing data for scientists to pick up and use in their research. The publication of this paper shows that we have been successful in this phase. We’re now continuing to consolidate everything and expand geographically.
