Identifying and protecting macroalgae detritus sinks toward climate change mitigation

Queiros, AM, Tait, K, Clark, JR, Bedington, M, Pascoe, CK, Torres, R, Somerfield, PJ and Smale, DA 2022 Identifying and protecting macroalgae detritus sinks toward climate change mitigation. Ecological Applications.

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Harnessing natural solutions to mitigate climate change requires an understanding of carbon 18 fixation, flux and sequestration across ocean habitats. Recent studies suggest that exported 19 seaweed particulate organic carbon is stored within soft sediment systems. However, very 20 little is known about how seaweed detritus disperses from coastlines, or where it may enter 21 seabed carbon stores, where it could become the target of conservation efforts. Here, focusing 22 on regionally dominant seaweed species, we surveyed environmental DNA (eDNA) of 23 natural coastal sediments, and studied their connectivity to seaweed habitats using a particle 24 tracking model parameterized to reproduce seaweed detritus dispersal behavior based on 25 laboratory observation of seaweed fragment degradation and sinking. Experiments showed Page 1 of 42 Ecological Applications Article 2 26 seaweed detritus density changing over time, differently across species. This, in turn, 27 modified distances travelled by released fragments until they reached the seabed for the first 28 time, during model simulations. Dispersal pathways connected detritus from the shore to the 29 open ocean but, importantly, also to coastal sediments, and this was reflected by field eDNA 30 evidence. Dispersion pathways were also affected by hydrodynamic conditions, varying in 31 space and time. Both the properties and timing of released detritus, individual to each 32 macroalgal population, and short-term near-seabed and medium-term water-column transport 33 pathways, are thus seemingly important in determining the connectivity between seaweed 34 habitats and potential sedimentary sinks. Studies such as this one, supported by further field 35 verification of sedimentary carbon sequestration rates and source partitioning, are still needed 36 to help quantify the role of seaweed in the ocean carbon cycle. Such studies will provide vital 37 evidence to inform on the potential need to develop blue carbon conservation mechanisms, 38 beyond wetlands.

Item Type: Publication - Article
Additional Keywords: blue carbon, climate change, conservation, lagrangian, mitigation, seaweed
Divisions: Plymouth Marine Laboratory > Science Areas > Marine Ecology and Biodiversity
Depositing User: S Hawkins
Date made live: 25 Jan 2023 10:48
Last Modified: 25 Jan 2023 10:48

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