Embracing complexity: Exploring carbon sequestration in two highly interconnected ecosystems    

Zoe Penno, Intern for the Coastal Carnivores and Carbon Project, shares about what she's discovered during her time at Raincoast.

During my undergraduate studies, I couldn’t pinpoint my ecological interests to a single ecosystem type, species, or phylum. However, my perspective changed when I immersed myself in papers discussing trophic relationships and nutrient transfer across different ecological systems; I began to understand how all ecosystems are intrinsically interconnected. This realization led me to embrace the opportunity to conduct research that encompasses multiple ecological systems. Fast forward to today, I am doing exactly this as an intern with Raincoast working on the Coastal Carnivores and Carbon (CCC) project and am eager to follow a similar trajectory for my Masters research at the University of Victoria this fall.

The CCC project seeks to explore the role salmon abundance and large carnivore foraging activities play in carbon sequestration in coastal ecosystems in British Columbia. Specifically, this project aims to explore the impacts of large carnivore extirpation and consequently, an interrupted trophic cascade on carbon sequestration potential and adaptation to climate change. This disruption of trophic cascades has been seen across the Gulf Islands, primarily attributed to the elimination of apex predators, resulting in booming populations of prey species, namely mesopredators (i.e., racoons) and deer. 

Trophic cascade

Trophic cascade is the downstream effects predators have on food-webs. That is, predators influence the abundance or behaviour of prey species which in turn influences the local plant community. 

My role in this project has been to review and compile literature on carbon sequestration, trophic cascades, and climate change adaptation and design methodology to guide future research. The CCC project encompasses multiple ecosystems, presenting a valuable opportunity for me to experience the complexities of multifaceted research design.

The complexities of carbon

To be candid, when I embarked on this project, I may have underestimated the intricacies involved in designing a study centered around the complex process of soil-carbon sequestration. When considering carbon stored within an ecosystem my thoughts gravitate towards the living biomass, such as tree trunks, lush leaf canopies, and abundant vegetation covering the ground. Surprisingly, soil acts as the primary reservoir, harboring almost 80% of the carbon stored in terrestrial ecosystems. This substantial amount of carbon originates from the decomposition of plant and animal remains, as well as the transfer of carbon-enriched compounds from roots to soil microbes.

Bear print in the sand.
Photo by Alex Harris / Raincoast Conservation Foundation.
In tact forest with snow.
Photo by Alex Harris / Raincoast Conservation Foundation.

On the surface, designing this research appeared straightforward: establish connections between predator activity and the quantity of carbon stored in the soil. However, this link proves to be challenging as the path between predator impacts (via prey abundance reduction, instilling prey fear, or direct transfer of organic matter to the soil) and soil organic carbon is long, winding, and indirect. Along this pathway are factors including the nature and abundance of prey and plant species, both of which can regulate soil organic carbon independent of predators, in addition to numerous environmental and climatic variables. Nonetheless, the complexity of this project should neither dishearten nor deter us, as it underscores the deeply interconnected nature of these processes and highlights the vast realm of discovery that remains regarding the role of each organism in our planet’s greater ecosystem.

As I approach the start of my Master’s degree program at the University of Victoria this fall, I have been inspired to delve deeper into the study of intertrophic (interactions or relationships between different feeding positions of organisms within the food-web) and interspecific relationships (interactions or relationships between different species within an ecological community). Specifically, I hope to explore the dynamics between terrestrial predators and intertidal prey along marine protected areas (MPAs) across Vancouver Island. Through this research, my objective is to fill in knowledge gaps surrounding trophic interactions throughout the intertidal zone and shed light on conservation strategies for carnivores and prey species inhabiting coastal areas of British Columbia.

I look forward to embracing the intricacies and uncertainties of ecosystem science as I embark on my graduate studies, much like I did while contributing to the CCC project at Raincoast. This project has served as a reminder that studying open systems often yields inconclusive answers. Nevertheless, it is important to recognize that such research still holds value and significance. Therefore, I am reminded how crucial it is to critically evaluate our own methods and comprehend how to interpret the results, considering the inherent challenge of controlling all factors within an ecosystem. Working with Raincoast has provided me with a perfect introduction, facilitating a smooth transition into my own graduate research. I am immensely grateful for the opportunity to contribute to such a fascinating topic and hope to collaborate again in the future.

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Sam Scott and Peter Ross standing in front of the future mobile lab, which is a grey sprinter van.