March 2023 | By Nicole Foster and Simon Brandl | Photos by Jordan Casey

Dr. Nicole Foster is a MarineGEO Postdoc. She is working with Dr. Simon Brandl on the BEACON project. Dr. Simon Brandl is an assistant professor in the Department of Marine Science at The University of Texas at Austin. He serves as one of the co-directors of the Gulf Coast, Texas MarineGEO Observatory.  

To tap the power and creativity of our international network, MarineGEO supports finite, comparative network-wide research experiments proposed by partners around the network. In 2022 MarineGEO launched the BEACON (Biodiversity and Energy Availability across a Coastal Ocean Network) project. BEACON seeks to understand how productivity is related to animal biodiversity—a key question in the modern ocean awash in productivity-boosting nutrients produced by humanity. The project targets MarineGEO sites around the world using environmental DNA and biogeochemical analyses of water samples. 

^{A vibrant biodiverse coral reef in Conflict Islands, Papua New Guinea.}

Our oceans are full of life. The countless species occurring beneath the waves inhabit many environments, from seagrass beds, coral reefs, and mangroves to sandy sediments and the deep ocean. Not all environments are created equal though, with some harbouring greater diversity than others. Explaining the resulting diversity gradients has occupied ecologists for decades. Among the many hypotheses that have been developed is the species-energy hypothesis, which proposes that the more available energy a system has, the more species can be supported and co-exist without having to compete strongly. Although it appears intuitive, the species-energy relationship is hard to disentangle in practice, and exhibits different trends depending on the spatial scale of the study (i.e., whether local or regional). Furthermore, few attempts have been made to test the species-energy relationship in marine rather than terrestrial ecosystems.  

BEACON will leverage the global reach of MarineGEO to test the species-energy relationship in marine systems worldwide, encompassing both local and regional trends. Understanding patterns of biodiversity in the marine environment is a central goal of MarineGEO, and BEACON provides unique opportunities to build understanding of marine diversity that can then be applied to managing the ocean’s changing ecosystems.  

To examine how global biodiversity and productivity are related in coastal marine communities, we will employ two powerful approaches. The first is environmental DNA, which is an emerging approach that uses traces of animal DNA in water to detect which species are or were present. It is useful in detecting invasive species, reconstructing past biodiversity, and tracking changes in biodiversity. It builds on the premise that DNA shed by organisms acts as a fingerprint, allowing us to trace it back to the original owner. By collecting water samples, extracting the DNA, and amplifying regions of DNA specific to animals, we will recover a snapshot of biodiversity at specific sampling sites.  

^{Example of high diversity fish community in Savusavu, Fiji.}

To correlate this with the available energy within a system, we will use a second powerful approach, examining the particulate organic matter (POM) in seawater. POM is comprised of various organic molecules, but we are particularly interested in organic carbon, which indicates the quantity of energy (measured as organic matter) in the system, and hydrolysable amino acids, which shed light on the quality of this organic matter, i.e., whether it is fresh or degraded. Both quantity and quality of organic matter are important to ascertain the ‘fresh’ energy available to organisms in the ecosystem.    

But diversity and productivity are not enough to understand how these ecosystems work. Therefore, we will also measure how environmental conditions at different sites influence marine food web structure and function. This is important for predicting how human society changes marine ecosystems by, for example, increasing delivery of organic matter to the ocean by rivers. Finally, the project advances MarineGEO’s central mission of establishing methods to track biodiversity by testing eDNA, meaning that MarineGEO sites can be tracked in the future to document changes in ecosystem structure and function.  

Overall, BEACON seeks to answer the following questions: 

1. What is the relationship between energy availability and animal biodiversity across the world’s coastal marine ecosystems? 
2. How is this relationship influenced by spatial scale, seasonal variability, and environmental or human influences? 
3. Does the quality and quantity of organic matter foster distinct trophic community structure and energy fluxes?