Kelp carbon sink potential decreases with warming due to accelerating decomposition

Cycling of organic carbon in the ocean has the potential to mitigate or exacerbate global climate change, but major questions remain about the environmental controls on organic carbon flux in the coastal zone. Here, we used a field experiment distributed across 28° of latitude, and the entire range of 2 dominant kelp species in the northern hemisphere, to measure decomposition rates of kelp detritus on the seafloor in relation to local environmental factors. Detritus decomposition in both species were strongly related to ocean temperature and initial carbon content, with higher rates of biomass loss at lower latitudes with warmer temperatures. Our experiment showed slow overall decomposition and turnover of kelp detritus and modeling of coastal residence times at our study sites revealed that a significant portion of this production can remain intact long enough to reach deep marine sinks. The results suggest that decomposition of these kelp species could accelerate with ocean warming and that low-latitude kelp forests could experience the greatest increase in remineralization with a 9% to 42% reduced potential for transport to long-term ocean sinks under short-term (RCP4.5) and long-term (RCP8.5) warming scenarios. However, slow decomposition at high latitudes, where kelp abundance is predicted to expand, indicates potential for increasing kelp-carbon sinks in cooler (northern) regions. Our findings reveal an important latitudinal gradient in coastal ecosystem function that provides an improved capacity to predict the implications of ocean warming on carbon cycling. Broad-scale patterns in organic carbon decomposition revealed here can be used to identify hotspots of carbon sequestration potential and resolve relationships between carbon cycling processes and ocean climate at a global scale.publishedVersio

Listening to the Sea: Clam Garden Restoration in Gulf Islands National Park Reserve

The six-year joint project between Parks Canada and WSANEC and Hul’q’umi’num Nations to restore and manage beaches will be introduced. This project experimentally restores clam gardens and revitalizes First Nations\u27 cultural practices in the Gulf Islands National Park Reserve. These clam gardens are becoming a nexus of rediscovery and learning and are bringing together people of all ages, from different Nations, professions and disciplines

Our Island Relatives

STOLȻEȽ (John Elliott) & W̱SÁNEĆ Clam Garden Traditional Knowledge Working Group This session will feature a W̱SÁNEĆ elder and knowledge holder who will speak about our Island relatives and the importance of language to who we are. Language connects what we believe about the islands, what we believe about clams, and what we believe about all the fishes in our territory. This session will include stories and describe our sacred connections to land through language, beliefs, laws and how it relates to aboriginal rights and title and treaty rights

Quantifying Food Species Produced by Ancient Clam Garden Technologies of the Salish Sea

Adaptation to food systems impacted by climate change is one of the greatest challenge facing the world today. Indigenous peoples of North America have built a body of knowledge that is based on experience and awareness of the natural world around them. Since time immemorial, First Nations have shaped the environment to create and maintain highly productive food systems. One example of this knowledge is the ancient mariculture known as clam gardens, a purposely constructed rock-walled terrace that increases the habitat and productivity of traditional foods. This study aims to quantify the food species found within the rock wall structure of a clam garden compared to a non-walled beach to provide a baseline representation of the food species associated with a modified beach. This was done using low tide observational surveys to measure the abundance of edible invertebrates found within the intertidal portion of a clam garden rock wall and control site. Data analysis shows higher abundance of individual invertebrates found at the clam garden rock wall compared to the control non modified beach. The rock wall site show a significant difference in diversity of food species found compared to the control non-walled site. This research supports a growing understanding that Indigenous communities have been active managers of ecosystems and food systems for thousands of years, and highlights the positive relationship that can exist between increased ecosystem productivity and abundance of traditional foods

Introduction

In the sprit of the Clam Garden Network this session will begin with a welcome and introduction from an appropriate First Nation community member. The Clam Garden Network is a group of First Nations, academics, researchers, and resource managers from coastal British Columbia, Washington State, and Alaska who are interested in the cultural and ecological importance of traditional clam management practices and features, including clam gardens. We share ideas, research approaches, tools, and data to better inform our knowledge about how people used intertidal resources and ecosystems. We see clam gardens as a compelling focal point for a series of linked current social issues, such as food security, First Nations governance, and inter-generational knowledge sharing. For more information please see http://clamgarden.co

Assessing the Impacts of Clam Gardens on Invertebrate Species Diversity in the Salish Sea

The world’s oceans are impacted by human interactions that create largely negative consequences, however Indigenous societies have developed technologies and management practices that have been shown to have positive benefits on ecosystems and have sustained resources for millennia. One such technology is clam gardens; clam gardens are rock wall structures constructed by First Nations people within the intertidal area that trap sediment and extend the area for productive clam growth. Clam gardens have been shown to increase the abundance and growth rate of clams when compared to non-walled beaches. While researchers have primarily focused on how clam gardens have increased the productivity of clams, the rock wall structure may also alter conditions for other invertebrate species. In fact, ethnographic studies have shown that clam gardens had multiple purposes besides being productive bivalve habitats. To better understand the ecological role of clam gardens, this study quantified invertebrate community structure on a clam garden rock wall and compared it to a control non-walled beach with similar tidal height and wave energy. This research shows that the clam garden rock wall has greater invertebrate diversity and a different ecological community structure than similar non-walled beaches. This study acts as an example of how traditional technologies can aid in maintaining complex marine invertebrate communities. In this way, we can look to First Nations technologies that have worked for millennia and see how they may be implemented in modern applications to create sustainable solutions that can positively impact resilient ecosystems

Clam gardens: Stories about eco-cultural revival in the Salish Sea

For the first time in centuries, clam gardens in the Salish Sea are buzzing with life once again. Elders and youth, knowledge holders and scientists, are coming together to restore clam gardens, and along with them, revive language, connections to place, and the ecosystem. Together we are learning about this eco-cultural worldview and how it supports resilient interaction with the natural world. These stories will center on the exploration of the ecological and societal role of clam gardens through collaboration with Indigenous communities in the Salish Sea. Through the lens of eco-cultural sustainability, biophysical and human dimensions of clam gardens will be examined, emphasizing the reciprocal feedbacks that exist between people and place, and the role that clam gardens play in challenging outdated and simplistic views of Northwest Indigenous societies. Clam gardens will be used as an example of a shifted baseline; specifically, how nearshore management was previously both more active and transboundary compared to the modern context where a border creates highly asymmetrical governance. Specific examples will be drawn from a six-year joint project between Parks Canada and WSANEC and Hul’q’umi’num Nations to restore and manage beaches. This project experimentally restores clam gardens and revitalizes First Nations\u27 cultural practices in the Gulf Islands National Park Reserve. These clam gardens are becoming a nexus of rediscovery and learning and are bringing together people of all ages, from different Nations, professions and disciplines

Ancient Mariculture in the Salish Sea: Documenting the Past for the Future

In the Salish Sea, as elsewhere, the recognition and re-establishment of traditional mariculture practices are linked to issues of food security, health, economic development, governance, and community engagement in heritage. The Clam Garden Network is a collaborative team of First Nations knowledge holders, archaeologists, and ecologists who focus on traditional marine resource management systems throughout the Northwest Coast. In several locations in the Salish Sea, we have 1) documented the location of ancient mariculture features (clam gardens and cleared beaches) and associated terrestrial archaeological sites; 2) conducted ecological surveys and experiments that suggest clam abundance, growth and survival are higher in extant clam gardens beaches than in other beaches; 3) collected zooarchaeological samples to assess ecological changes in ancient clam gardens; 4) recorded local knowledge about the social and ecological aspects of traditional mariculture; and 5) dated the construction of ancient mariculture features. Inter-disciplinary and inter-community efforts are an effective way to document traditional resource management systems, as well as situating them within current socio-political and ecological contexts

Kelp carbon sink potential decreases with warming due to accelerating decomposition

Cycling of organic carbon in the ocean has the potential to mitigate or exacerbate global climate change, but major questions remain about the environmental controls on organic carbon flux in the coastal zone. Here, we used a field experiment distributed across 28° of latitude, and the entire range of 2 dominant kelp species in the northern hemisphere, to measure decomposition rates of kelp detritus on the seafloor in relation to local environmental factors. Detritus decomposition in both species were strongly related to ocean temperature and initial carbon content, with higher rates of biomass loss at lower latitudes with warmer temperatures. Our experiment showed slow overall decomposition and turnover of kelp detritus and modeling of coastal residence times at our study sites revealed that a significant portion of this production can remain intact long enough to reach deep marine sinks. The results suggest that decomposition of these kelp species could accelerate with ocean warming and that low-latitude kelp forests could experience the greatest increase in remineralization with a 9% to 42% reduced potential for transport to long-term ocean sinks under short-term (RCP4.5) and long-term (RCP8.5) warming scenarios. However, slow decomposition at high latitudes, where kelp abundance is predicted to expand, indicates potential for increasing kelp-carbon sinks in cooler (northern) regions. Our findings reveal an important latitudinal gradient in coastal ecosystem function that provides an improved capacity to predict the implications of ocean warming on carbon cycling. Broad-scale patterns in organic carbon decomposition revealed here can be used to identify hotspots of carbon sequestration potential and resolve relationships between carbon cycling processes and ocean climate at a global scale

Kelp carbon sink potential decreases with warming due to accelerating decomposition

Cycling of organic carbon in the ocean has the potential to mitigate or exacerbate global climate change, but major questions remain about the environmental controls on organic carbon flux in the coastal zone. Here, we used a field experiment distributed across 28° of latitude, and the entire range of 2 dominant kelp species in the northern hemisphere, to measure decomposition rates of kelp detritus on the seafloor in relation to local environmental factors. Detritus decomposition in both species were strongly related to ocean temperature and initial carbon content, with higher rates of biomass loss at lower latitudes with warmer temperatures. Our experiment showed slow overall decomposition and turnover of kelp detritus and modeling of coastal residence times at our study sites revealed that a significant portion of this production can remain intact long enough to reach deep marine sinks. The results suggest that decomposition of these kelp species could accelerate with ocean warming and that low-latitude kelp forests could experience the greatest increase in remineralization with a 9% to 42% reduced potential for transport to long-term ocean sinks under short-term (RCP4.5) and long-term (RCP8.5) warming scenarios. However, slow decomposition at high latitudes, where kelp abundance is predicted to expand, indicates potential for increasing kelp-carbon sinks in cooler (northern) regions. Our findings reveal an important latitudinal gradient in coastal ecosystem function that provides an improved capacity to predict the implications of ocean warming on carbon cycling. Broad-scale patterns in organic carbon decomposition revealed here can be used to identify hotspots of carbon sequestration potential and resolve relationships between carbon cycling processes and ocean climate at a global scale