High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

https://www.umces.edu/jeremy-testaHigh-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

High-resolution data-assimilative models are needed to support real-world testing of macroalgal CDR pathways. These modeling tools must:

• Account for complex interactions in the vicinity of the farm and downstream impacts^[1]van der Molen, J., Ruardij, P., Mooney, K., Kerrison, P., O’Connor, N.E., Gorman, E., Timmermans, K., Wright, S., Kelly, M., Hughes, A.D., Capuzzo, E., 2018. Modelling potential production of macroalgae farms in UK and Dutch coastal waters. Biogeosciences 15, 1123–1147. https://doi.org/10.5194/bg-15-1123-2018 ^[2]Coastal Dynamics Laboratory, https://faculty.sites.uci.edu/davis/methodology/
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of macroalgae cultivation. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from macroalgae must include estimates of the “opportunity cost” of macroalgal carbon sequestration (how much production and export would have occurred in natural phytoplankton communities in the absence of a macroalgal farm?) as well as any enhancements to marine ecosystem productivity due to the presence of a macroalgal farm (is phytoplankton production enhanced above background levels due to the presence of macroalgae farms?).

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from macroalgae cultivation, allowing for informed placement of sensors to monitor the field trials.
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake).
• Inform a prioritized set of predictions to be tested during field trials.

Proof-of-concept field trials are urgently needed to test both cultivation and sequestration technologies, as well as the full array of impacts. Field trials are needed to test predictions regarding: 

• Cultivation yields and their dependence on species, ocean basin, nutrient availability, and farm design among others
• Performance of deep-water moorings
• Impacts to pelagic marine ecosystems
• Performance of harvesting technologies
• Additional CO₂ uptake from the atmosphere into the macroalgae

• "Answering Critical Questions About Sinking Macroalgae for Carbon Dioxide Removal" (2022)

Proof-of-concept field trials are urgently needed to test both cultivation and sequestration technologies, as well as the full array of impacts. Field trials are needed to test predictions regarding: 

• Cultivation yields and their dependence on species, ocean basin, nutrient availability, and farm design among others
• Performance of deep-water moorings
• Impacts to pelagic marine ecosystems
• Performance of harvesting technologies
• Additional CO₂ uptake from the atmosphere into the macroalgae

• "Answering Critical Questions About Sinking Macroalgae for Carbon Dioxide Removal" (2022) ^[1]https://oceanvisions.org/our-programs/macroalgaeresearchframework/

Proof-of-concept field trials are urgently needed to test both cultivation and sequestration technologies, as well as the full array of impacts. Field trials are needed to test predictions regarding: 

• Cultivation yields and their dependence on species, ocean basin, nutrient availability, and farm design among others
• Performance of deep-water moorings
• Impacts to pelagic marine ecosystems
• Performance of harvesting technologies
• Additional CO₂ uptake from the atmosphere into the macroalgae

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers, and more to:

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches, much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers, and more to:

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers and more to:

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers and more to:

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers and more to:

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers and more to:

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers and more to:

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers and more to: 

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers and more to: 

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. Given the extensive amount of macroalgae cultivated and harvested in the coastal zone, we have more advanced knowledge of the scale impacts of natural accretion into sediments. We now need a global research effort around the fate and impacts of sinking seaweed in the deep ocean. To advance this agenda we need to convene scientists, engineers, seaweed farmers and more to: 

• Identify existing deep-sea observatories, facilities, and vehicles to accelerate research on the fate of macroalgal carbon intentionally sunk in the deep ocean
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials
• Collaborate with existing farms to conduct field trials. This may be especially important for offshore farms that may be more representative of the open ocean conditions necessary to scale cultivation to achieve globally relevant CDR.
• Evaluate the potential to conduct sinking trials with portions of the supply of floating Sargassum patches to evaluate CDR and environmental impacts of sinking. Globally, there are ~10 gigatons of carbon in these Sargassum patches^[1]Gouvêa LP, Assis J, Gurgel CFD, Serrão EA, Silveira TCL, Santos R, Duarte CM, Peres LMC, Carvalho VF, Batista M, Bastos E, Sissini MN, Horta PA. Golden carbon of Sargassum forests revealed as an opportunity for climate change mitigation. Sci Total Environ. 2020 Aug 10;729:138745. doi: 10.1016/j.scitotenv.2020.138745. Epub 2020 Apr 17. Erratum in: Sci Total Environ. 2021 Apr 15;765:144696. PMID: 32498159. , much of which is otherwise destined to end up on beaches, where it may become an environmental nuisance and will decompose, returning its carbon to the atmosphere. This may also serve as a way of generating public support for macroalgae CDR given the considerable social, economic, and environmental issues caused by Sargassum patches. 
• Review oceanographic data from past cruises, coastal observing systems, and buoy data to acquire needed physical, chemical, and biological information to assess site potential for field experiments. 
  • Data from pilot studies investigating the effects of kelp on local mitigation of ocean acidification (e.g., in the state of Washington, USA) may also provide useful information on macroalgae growth rates/carbon sequestration rates, as well as environmental co-benefits and risks.

Research, development, and demonstration of macrolgae CDR may be accelerated and strengthened by creating partnerships with key industries/sectors, including:  

• Integrated multi-trophic aquaculture: Integration with finfish and shellfish to leverage cost savings with operations and achieve permaculture-style benefits (macroalgae can take up waste products generated by fish; fish can feed on macroalgae, the increase in pH from the presence of algae can also be beneficial for shellfish whose growth is already threatened by ocean acidification).
• Offshore wind farms are often viewed as “dead space” for other marine spatial uses, but could provide power sources and platforms for macroalgal farms
• Microalgae companies to adopt best practices for shore-based nursery facilities, such as nutrient and light needs to optimize growth and facility design(s) that maximize growth potential and minimize cost.

Developing and strengthening relationships with partner industries may also help promote public support, as well as potentially offer faster routes to obtaining the necessary permitting.

Research, development, and demonstration of macrolgae CDR may be accelerated and strengthened by creating partnerships with key industries/sectors, including:  

• Integrated multi-trophic aquaculture^[1]García-Poza, S., Leandro, A., Cotas, C., Cotas, J., Marques, J.C., Pereira, L. and Gonçalves, A.M., 2020. The Evolution Road of Seaweed Aquaculture: Cultivation Technologies and the Industry 4.0. International Journal of Environmental Research and Public Health, 17(18), p.6528. : Integration with finfish and shellfish to leverage cost savings with operations and achieve permaculture-style benefits (macroalgae can take up waste products generated by fish; fish can feed on macroalgae, the increase in pH from the presence of algae can also be beneficial for shellfish whose growth is already threatened by ocean acidification).
• Offshore wind farms are often viewed as “dead space” for other marine spatial uses, but could provide power sources and platforms for macroalgal farms
• Microalgae companies to adopt best practices for shore-based nursery facilities, such as nutrient and light needs to optimize growth and facility design(s) that maximize growth potential and minimize cost.

Developing and strengthening relationships with partner industries may also help promote public support, as well as potentially offer faster routes to obtaining the necessary permitting.

Research, development, and demonstration of macrolgae CDR may be accelerated and strengthened by creating partnerships with key industries/sectors, including:  

• Integrated multi-trophic aquaculture^[1]García-Poza, S., Leandro, A., Cotas, C., Cotas, J., Marques, J.C., Pereira, L. and Gonçalves, A.M., 2020. The Evolution Road of Seaweed Aquaculture: Cultivation Technologies and the Industry 4.0. International Journal of Environmental Research and Public Health, 17(18), p.6528. : Integration with finfish and shellfish to leverage cost savings with operations and achieve permaculture-style benefits (macroalgae can take up waste products generated by fish; fish can feed on macroalgae).
• Offshore wind farms are often viewed as “dead space” for other marine spatial uses, but could provide power sources and platforms for macroalgal farms
• Microalgae companies to adopt best practices for shore-based nursery facilities, such as nutrient and light needs to optimize growth and facility design(s) that maximize growth potential and minimize cost.

Developing and strengthening relationships with partner industries may also help promote public support, as well as potentially offer faster routes to obtaining the necessary permitting.

Research, development, and demonstration of macrolgae CDR may be accelerated and strengthened by creating partnerships with key industries/sectors, including:  

• Integrated multi-trophic aquaculture: Integration with finfish and shellfish to leverage cost savings with operations and achieve permaculture-style benefits (macroalgae can take up waste products generated by fish; fish can feed on macroalgae).
• Offshore wind farms are often viewed as “dead space” for other marine spatial uses, but could provide power sources and platforms for macroalgal farms
• Microalgae companies to adopt best practices for shore-based nursery facilities, such as nutrient and light needs to optimize growth and facility design(s) that maximize growth potential and minimize cost.

Developing and strengthening relationships with partner industries may also help promote public support, as well as potentially offer faster routes to obtaining the necessary permitting.

First-Order Priorities to build public support for ocean-based CDR pathways are found in the Public Support road map, but there are some specific elements that can be emphasized to cultivate public support around macroalgae-based CDR:  

These include: 

• The perceived advantage of nature-based approaches for macroalgae pathways^[1]Bertram C and Merk C (2020) Public Perceptions of Ocean-Based Carbon Dioxide Removal: The Nature-Engineering Divide? Front. Clim. 2:594194. doi: 10.3389/fclim.2020.594194
• Identification and quantification of the co-benefits associated with macroalgae cultivation
• Inclusion of coastal blue carbon ecosystems as part of a campaign to build broad public support for macroalgae. 

First-Order Priorities to build public support for ocean-based CDR pathways are found in the Public Support road map, but there are some specific elements that can be emphasized to cultivate public support around macroalgae-based CDR:  

These include: 

• The perceived advantage of nature-based approaches for macroalgae pathways^[1]Bertram C and Merk C (2020) Public Perceptions of Ocean-Based Carbon Dioxide Removal: The Nature-Engineering Divide? Front. Clim. 2:594194. doi: 10.3389/fclim.2020.594194
• Identification and quantification of the co-benefits associated with macroalgae cultivation
• Inclusion of coastal blue carbon ecosystems as part of a campaign to build broad public support for macroalgae. 

First-Order Priorities to build public support for ocean-based CDR pathways are found in the Public Support road map, but there are some specific elements that can be emphasized to cultivate public support around macroalgae-based CDR:  

These include: 

• The perceived advantage of nature-based approaches for macroalgae pathways^[1]Bertram C and Merk C (2020) Public Perceptions of Ocean-Based Carbon Dioxide Removal: The Nature-Engineering Divide? Front. Clim. 2:594194. doi: 10.3389/fclim.2020.594194
• Identification and quantification of the co-benefits associated with macroalgae cultivation
• Inclusion of coastal blue carbon ecosystems as part of a campaign to build broad public support for macroalgae. 

First-Order Priorities to build public support for ocean-based CDR pathways are found in the Public Support road map, but there are some specific elements that can be emphasized to cultivate public support around macroalgae-based CDR:  

These include: 

• The perceived advantage of nature-based approaches for macroalgae pathways^[1]Bertram C and Merk C (2020) Public Perceptions of Ocean-Based Carbon Dioxide Removal: The Nature-Engineering Divide? Front. Clim. 2:594194. doi: 10.3389/fclim.2020.594194
• Identification and quantification of the co-benefits associated with macroalgae cultivation
• Inclusion of coastal blue carbon ecosystems as part of a campaign to build broad public support for macroalgae.