WP_Post Object ( [ID] => 1735 [post_author] => 2 [post_date] => 2021-07-12 16:22:43 [post_date_gmt] => 2021-07-12 16:22:43 [post_content] => Carbon dioxide removal (CDR) is a term used to describe anthropogenic activities that directly or indirectly remove carbon dioxide (CO2) from the atmosphere and durably store it in geological, terrestrial, or ocean reservoirs, or in products. Marine carbon dioxide removal (mCDR) is a subset of CDR approaches that leverage the ocean to remove CO2 and/or store captured CO2 in ocean reservoirs.   Macroalgae, or seaweed, are fast-growing marine organisms that use photosynthesis to incorporate carbon from seawater into their living tissue. Macroalgae flourish in coastal and some pelagic environments and a portion of the seaweed produced is exported naturally to the deep sea where it may be buried or remineralized by marine food webs (Wu et al., 2023; Krause-Jensen & Duarte, 2016). Slow turnover times in most deep ocean environments will sequester carbon released to bottom waters for centuries or longer (Siegel et al., 2021). Recently, there have been proposals to cultivate macroalgae and then sink its biomass to the deep ocean to sequester carbon from the atmosphere. In theory, this could amplify the natural process of seaweed carbon sequestration and could remove additional carbon dioxide from the atmosphere (GESAMP 2019; NASEM 2022) however, significantly more research is needed to understand the potential efficacy and impacts from both environmental and social standpoints.   The cultivation of seaweed has been practiced for centuries. Asia continues to dominate seaweed mariculture, producing 99.5% of global yields, with the vast majority coming from just four countries: China, Indonesia, the Republic of Korea, and the Philippines. In 2015 the global production of seaweed totaled 30.4 million tonnes, of which over 1.1 million tonnes were wild harvest and 29.4 million tonnes were cultivated (in freshwater, brackish, and saltwater). Chile, China, and Norway were the leading producers of wild species while China, Indonesia, the Republic of Korea, and the Philippines led in cultivated species. Today, the global seaweed industry is worth over USD 6 billion per annum. In 2018, 32.4 million tonnes of aquatic algae were wild-collected and cultivated with a majority of macroalgal farming taking place in coastal waters (FAO 2018). Macroalgae is used in a vast array of food and non-food items globally but has yet to be farmed specifically for CDR purposes. Although several start-ups are proposing this with some beginning field trials and demonstration projects.  While historically dominated by a small number of countries, algae farming is becoming increasingly popular in Europe and North America, with a particular interest in climate change mitigation and contribution to the blue economy. There are wide knowledge and technology disparities across the globe with Asian countries, the European Union, and the United States leading the way with the most advanced farming practices including integrated multi-trophic aquaculture (Chopin & Tacon, 2020; García-Poza et al., 2020). History shows successful long-term cultivation and farming of seaweeds, and a revived interest in this aquatic organism promises great potential for innovation and climate change mitigation solutions (Duarte et al., 2017). [post_title] => Overview [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => overview [to_ping] => [pinged] => [post_modified] => 2025-04-11 11:48:17 [post_modified_gmt] => 2025-04-11 11:48:17 [post_content_filtered] => [post_parent] => 536 [guid] => https://oceanvisions.org/?page_id=1735 [menu_order] => 0 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 1744 [post_author] => 2 [post_date] => 2021-07-12 16:30:51 [post_date_gmt] => 2021-07-12 16:30:51 [post_content] =>

1. Carbon Capture - The ultimate CDR potential of large-scale macroalgal cultivation and sequestration is as yet difficult to determine. Recent consensus reports cite the following as possible carbon dioxide removal potential from macroalgae cultivation and sequestration:
   • 0.1 – 1.0 Gt CO2/year (NASEM 2022)
   • 0.1 – 0.6 Gt CO2/ year (NOAA 2023)

Theoretically, macroalgal cultivation and sequestration  could be scaled to between 0.1 - 1.0 Gt CO2/year (NASEM 2022, NOAA 2023), but realized CDR may be much lower due to a number of factors, including:

• • Competition for space with existing ocean stakeholders – commercial shipping,  commercial fishing, indigenous rights, marine protected areas, non-seaweed aquaculture, etc. 
  • Challenges with expanding to offshore environments – engineering of moorings  and farm structures, challenges with operations and maintenance in distant environments (Bak et al., 2020; Lovatelli et al., 2010), and the likely associated cost increases (at least at first)  associated with offshore operations
  • Most open ocean environments require nutrient additions to sustain macroalgal yields. If these nutrients come from the deep ocean, they will be accompanied by high CO₂ water that can be released and will offset macroalgal carbon sequestration to some degree (which needs to be quantified) (Pan et al., 2016; Oschlies et al., 2009).
    • If macroalgal farms are located closer to the coastal zone, excess anthropogenic nitrogen inputs could support ~3.5 million km2 of macroalgal cultivation, corresponding with an estimated CDR range of 5- 10 Gt CDR annually (NASEM workshop comments from Carlos Duarte, 2021), alleviating competition for “natural” nutrient supplies with phytoplankton and alleviating the need for an upwelled supply of nutrients (and the associated risks of releasing CO₂ from upwelled deep ocean waters).
  • It is hypothesized that macroalgae-based pathways could supply CDR at moderate cost ($25-125 per ton of CO₂ removed) (Energy Futures Initiative, 2020; Capron et al., 2020; NASEM, 2022), but these cost estimates are preliminary and subject to change as macroalgae-based pathways advance in technological readiness.
    • Researchers at UC Irvine have developed a biophysical-economic model (G-MACMODS) to better understand the geophysical, biological, and economic sensitivities of macroalgae-based CDR pathways (DeAngelo et al., 2022). Also, see the affiliated site suitability tool.

 

2. Sequestration Permanence -For cultivated macroalgae to contribute to CDR, the carbon captured in the macroalgal tissue needs to be sequestered to prevent its decomposition and return to the atmosphere. Sequestration pathways include:

• • Intentionally sinking the macroalgae (pre- or post-processing) into the deep ocean (>1000 meters depth) where it can be sequestered from contact with the atmosphere for hundreds to a few thousand years (if remineralized in the deep ocean) or for thousands-to-millions of years (if buried in marine sediments) (GESAMP 2019).
    • There are natural analogs to this process already. In macroalgal systems, already ~50% of natural macroalgal production breaks off and becomes dissolved or particulate organic matter. Some of the particulate organic matter is transported to the deep ocean, where the carbon is sequestered (Krause-Jensen & Duarte, 2016).
  • Relying on sedimentary burial below or adjacent to the farm (typically more applicable for farms not located over deep water) (Duarte et al., 2023)
  • Harvesting the macroalgae for:
    • Bioenergy (Hughes et al., 2013)
      • Combining combustion pathways with carbon capture and storage (thousands-to-millions of years if stored in a geologic reservoir) (Mereira & Pires, 2016)
      • Pyrolysis, resulting in biochar (hundreds to thousands of years) (Zhang et al., 2020; Roberts et al., 2015)
    • Production of long-lived bioproducts, such as bioplastics, that are capable of permanent (>100 years) sequestration (Albright & Fujita, 2023; Chia et al., 2020)

3. Differentiating from Avoided Emissions - Macroalgae can provide a number of other services that either reduce or replace greenhouse gas emissions, but do not remove legacy carbon dioxide pollution from the atmosphere. One example of reducing emissions: red algal supplements added to cattle feed may play a key role in reducing enteric methane emissions from cattle by over 50% (Roque et al., 2019; Vijn et al., 2020). Given methane’s potency as a greenhouse gas, such emissions reductions may play an outsized role in slowing planetary temperature increases through the reduction of greenhouse gases. Macroalgae biomass may also be converted into short-lived, high-value bioproducts, such as food and nutritional supplements (Biris-Dorhoi et al., 2020). This process may contribute to avoided emissions if it substitutes for carbon-intensive feedstocks, but it does not represent CDR because of the short timescale over which these products sequester carbon before it returns to the atmosphere. Although the focus of this roadmap is on macroalgae pathways for CDR, many of the obstacles faced, development needs, and near-term opportunities for advancement are relevant to these associated pathways for avoided greenhouse gas emissions.

[post_title] => CDR Potential [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => cdr-potential [to_ping] => [pinged] => [post_modified] => 2025-04-11 11:48:27 [post_modified_gmt] => 2025-04-11 11:48:27 [post_content_filtered] => [post_parent] => 536 [guid] => https://oceanvisions.org/?page_id=1744 [menu_order] => 1 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 1746 [post_author] => 2 [post_date] => 2021-07-12 16:32:06 [post_date_gmt] => 2021-07-12 16:32:06 [post_content] => Chemical 

• Localized buffering/reductions in ocean acidification due to CO₂ uptake. (Koweek et al., 2016; Hirsh et al., 2020; Kapsenberg & Cyronak 2019; Fernández et al., 2019; Xiao et al., 2021)

Biological

• Nutrient remediation and metal uptake in eutrophied, polluted coastal waters (Neveux et al., 2018)
• Building macroalgae cultivation facilities near shellfish or fish aquaculture facilities may alleviate negative impacts from such activities (NASEM 2022) (e.g., deoxygenation, eutrophication)

Physical

• Macroalgae farms may attenuate wave energy (Mork, 1996)
• Creation of habitat with resulting nurseries for fish and other marine life (Smale et al., 2013)

Other

• Carbon capture at sea may reduce the demand for terrestrial-based CDR alternatives that compete for land and/or freshwater

[post_title] => Environmental Co-benefits [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => environmental-co-benefits [to_ping] => [pinged] => [post_modified] => 2024-04-18 23:43:23 [post_modified_gmt] => 2024-04-18 23:43:23 [post_content_filtered] => [post_parent] => 536 [guid] => https://oceanvisions.org/?page_id=1746 [menu_order] => 2 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 1748 [post_author] => 2 [post_date] => 2021-07-12 16:32:51 [post_date_gmt] => 2021-07-12 16:32:51 [post_content] => Chemical

• Macroalgae are known to release bromoform and other halomethanes (Carpenter et al., 2009; Mehlmann et al., 2020) , and thus, large-scale macroalgae cultivation seems likely to increase the release of these substances. This needs additional research as the natural marine sources of these gases are currently estimated to be responsible for around 9% of stratospheric ozone loss, including depletion due to anthropogenic causes (Tegtmeier et al., 2015).
• Production of methane, nitrous oxide, and other potentially hazardous gases by the macroalgae
• The potential for CO₂ outgassing from pumping deep water to the surface  (artificial upwelling) to supply needed nutrients for the macroalgae (Pan et al., 2015).
• Ecological and biogeochemical (especially acidification and hypoxia) impacts in the deep sea from sinking large quantities of macroalgae into the deep ocean
  • Such effects are likely to be location-specific
• The remineralization of sunken seaweed may lead to oxygen depletion and acidification (Wu et al., 2023, Ocean Visions 2022)

  Biological

• Impacts to biodiversity and ecosystem function from large-scale cultivation operations, including (Campbell et al., 2019):
  • Enhanced disease and parasite risk
  • Alteration of population genetics
  • Introduction of non-native species into new environments
• Enhancement in epiphytic calcifiers that could offset carbon sequestration through calcification-induced CO₂ release
• Reduced phytoplankton production in and around large macroalgae farms due to competition for nutrients and light
• Ecological and biogeochemical (especially acidification and hypoxia) impacts in the deep sea from sinking large quantities of macroalgae into the deep ocean
  • Such effects are likely to be location-specific

  Physical

• Changes in light and nutrient availability (including possible changes in ocean albedo)
• In near-coastal zones, changes in circulation patterns due to drag by the seaweed could change residence time in nearshore environments
  • Changes in coastal residence time may affect the prevalence and intensity of harmful algal blooms (HABs)
• Entanglement of marine megafauna (e.g., whales)

  Other Addition of noise pollution due to vessel traffic and machinery [post_title] => Environmental Risks [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => environmental-risks [to_ping] => [pinged] => [post_modified] => 2024-04-18 23:48:48 [post_modified_gmt] => 2024-04-18 23:48:48 [post_content_filtered] => [post_parent] => 536 [guid] => https://oceanvisions.org/?page_id=1748 [menu_order] => 3 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 3090 [post_author] => 10 [post_date] => 2021-09-30 17:12:24 [post_date_gmt] => 2021-09-30 17:12:24 [post_content] => Enhance the Blue Economy: There is increased interest in the potential for seaweed aquaculture and its potential to increase economic opportunities for seaweed farmers if practices are modified to increase climate benefits and if these benefits are sufficiently monetized (Duarte et al., 2017).

• Job Creation: Seaweed farming could also present new job opportunities for fishers whose work is threatened by climate change (e.g., seaweed farming at Atlantic Sea Farms).
• Value-Added Products: High-value bioproducts (pigments, lipids, proteins, etc) can replace more carbon-intensive alternatives in feed, food, fuel, and other commodities (Albright & Fujita, 2023).

  [post_title] => Social Co-benefits [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => social-co-benefits [to_ping] => [pinged] => [post_modified] => 2024-04-18 23:50:46 [post_modified_gmt] => 2024-04-18 23:50:46 [post_content_filtered] => [post_parent] => 536 [guid] => https://oceanvisions.org/?page_id=3090 [menu_order] => 4 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 3082 [post_author] => 10 [post_date] => 2021-09-30 16:59:37 [post_date_gmt] => 2021-09-30 16:59:37 [post_content] =>

1. Competition for Space: Competition for space with existing ocean stakeholders – commercial shipping, commercial fishing, indigenous rights, marine protected areas, non-seaweed aquaculture, etc.
   • Potential for entanglement of macroalgae cultivation equipment with shipping, commercial fishing gear, aquaculture farms etc, particularly if the macroalgae farm is free floating
   • Protected sites include marine protected areas, world heritage sites, culturally significant areas, treaty-protected resources, ecologically or biologically significant marine areas, sensitive or vulnerable marine ecosystems, marine protected areas, and other effective area-based conservation measures.
2. Competition for Food: Given that macroalgae can be converted to nutrient dense food stuffs, there may also be social resistance to this method as it involves the willful destruction of viable food sources that could be used in furtherance of human food security (Stedt et al., 2022)
3. Financing: Financing any CDR approach brings with it the risk of creating inequity and decreasing social welfare (Cooley et al., 2022). With macroalgae cultivation, this may be especially applicable to coastal dwelling communities who rely on the ocean for their livelihoods, food, and cultural meaning.

[post_title] => Social Risks [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => societal-risks [to_ping] => [pinged] => [post_modified] => 2024-04-18 23:51:28 [post_modified_gmt] => 2024-04-18 23:51:28 [post_content_filtered] => [post_parent] => 536 [guid] => https://oceanvisions.org/?page_id=3082 [menu_order] => 5 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 1813 [post_author] => 4 [post_date] => 2021-07-16 18:32:56 [post_date_gmt] => 2021-07-16 18:32:56 [post_content] =>

• Proof-of-concept field experiments have not been conducted in open ocean conditions to test growth rates, sequestration potential, and environmental impacts of macroalgal CDR pathways (Accelerate Design and Permitting of Controlled Field Trials)
• Siting analyses are needed to identify optimal nutrient, light, and wave conditions for growth; as well as potential conflicts with other marine industries (such as the NOAA Coastal Aquaculture Siting and Sustainability toolkit) (Develop New Modeling Tools to Support Design and Evaluation)
• A suite of tools and methodologies to estimate productivity, carbon capture, export, and sequestration, including direct and remote sensing approaches{{1}} needs to be built (Develop New Modeling Tools to Support Design and Evaluation, Measure the Scale and Impacts of CDR via Macroalgae Sinking, Develop New In-Water Tools for Autonomous CDR Operations). 
  • For sinking pathways, the challenges of following the carbon from source (farm) to deposition (seafloor) in energetically active environments (horizontal and vertical currents, turbulent areas, etc.) 
• We do not understand enough about the net CDR benefit from a life cycle perspective (Develop New Modeling Tools to Support Design and Evaluation, Accelerate Design and Permitting of Controlled Field Trials, Develop New In-Water Tools for Autonomous CDR Operations, Develop CDR Monitoring and Verification Protocols)
• Challenges exist verifying additional CO₂ uptake from the atmosphere to the ocean in a dynamic background as a result of macroalgae cultivation and sequestration CDR pathways (Hurd et al., 2023; Burger et al., 2023)(Develop New Modeling Tools to Support Design and Evaluation, Accelerate Design and Permitting of Controlled Field Trials, Develop New In-Water Tools for Autonomous CDR Operations)
• Inclusion of various macroalgal CDR into integrated assessment models to simulate and predict complex, global responses to macroalgal CDR. Examples include changes in CO₂ fluxes in other ecosystems via teleconnections (connections in Earth processes and non-continuous geographic regions, which are often caused by processes not immediately apparent from first principles), and to estimate permanence via the various macroalgal CDR pathways (Develop New Modeling Tools to Support Design and Evaluation)
• Increased knowledge base regarding the physiology (including heat tolerance) and genomics of a broader array of potential cultivars – beyond the ten most common - to understand their growth and carbon sequestration potential is needed (Develop New Modeling Tools to Support Design and Evaluation, Accelerate Design and Permitting of Controlled Field Trials) 
• Better understanding of how large-scale macroalgae cultivation affects the partitioning of carbon between particulate and dissolved phases, and its implications for CDR (Develop New Modeling Tools to Support Design and Evaluation, Accelerate Design and Permitting of Controlled Field Trials)

*See Ocean Visions' framework for global research on macroalgae cultivation and sinking which further outlines these knowledge gaps. [post_title] => Addressing Knowledge Gaps [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => addressing-knowledge-gaps [to_ping] => [pinged] => [post_modified] => 2024-04-17 20:44:59 [post_modified_gmt] => 2024-04-17 20:44:59 [post_content_filtered] => [post_parent] => 1669 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/development-gaps-and-needs/addressing-knowledge-gaps/ [menu_order] => 0 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 1814 [post_author] => 4 [post_date] => 2021-07-16 18:32:56 [post_date_gmt] => 2021-07-16 18:32:56 [post_content] =>

• Advances are needed in offshore mooring design, as well as viable, durable, and cost-effective farming systems for offshore cultivation technology (Bak et al., 2020).  (Develop New In-Water Tools for Autonomous CDR Operations)
• Current observational technologies (sensors, ROVs, AUVs, etc.) and modeling tools are not widespread or easily available to support field trials with the necessary spatial and temporal frequency of monitoring and sampling (Develop New In-Water Tools for Autonomous CDR Operations)
• Technologies to accelerate macroalgal sinking are not well explored or understood (Accelerate Design and Permitting of Controlled Field Trials, Develop New In-Water Tools for Autonomous CDR Operations)
• Wave-powered devices (both for electrical power and upwelling) are in their infancy (Develop New In-Water Tools for Autonomous CDR Operations)
  • Upwelling systems must be designed and tested to access deeper water nutrients and keep them in the euphotic zone where they can support macroalgal growth (as opposed to immediately sinking out of the euphotic zone)
• Harvesting and processing technologies that minimize environmental impact and energy use are needed (Develop New In-Water Tools for Autonomous CDR Operations)
  • More efficient means of drying the harvested crop (for non-sinking pathways)
• Technologies to scale shore-based hatcheries to produce more juvenile kelp ready for outplanting are needed (Develop New In-Water Tools for Autonomous CDR Operations)

[post_title] => Engineering Challenges and Needs [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => engineering-challenges-and-needs [to_ping] => [pinged] => [post_modified] => 2024-04-18 23:52:40 [post_modified_gmt] => 2024-04-18 23:52:40 [post_content_filtered] => [post_parent] => 1669 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/development-gaps-and-needs/engineering-challenges-and-needs/ [menu_order] => 1 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 1815 [post_author] => 4 [post_date] => 2021-07-16 18:32:56 [post_date_gmt] => 2021-07-16 18:32:56 [post_content] =>

• Training, skills development, and technology transfers are needed globally to expand available workforce for macroalgal cultivation and sequestration (Accelerate RD&D Through New Partnerships, Broaden Funding Base for RD&D, Growing & Maintaining Public Support) 
• Stable, increased research and development funding to build capacity in this sector, such as has been seen with the ARPA-E MARINER program in the US (Broaden Funding Base for RD&D)

[post_title] => Building a Global Workforce [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => building-a-global-workforce [to_ping] => [pinged] => [post_modified] => 2021-07-20 19:19:50 [post_modified_gmt] => 2021-07-20 19:19:50 [post_content_filtered] => [post_parent] => 1669 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/development-gaps-and-needs/building-a-global-workforce/ [menu_order] => 2 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 1816 [post_author] => 4 [post_date] => 2021-07-16 18:32:56 [post_date_gmt] => 2021-07-16 18:32:56 [post_content] =>

• Certification standards for macroalgal carbon sequestration are needed to support developing markets for macroalgae CO₂ sequestration (Develop CDR Monitoring and Verification Protocols) 
• Scalable business models and markets to support demand for the multitude of potential products that can be derived from macroalgae (nutritional supplements, high value food items, additives, biochar, bioenergy, etc.) are needed to support this industry (Accelerate RD&D Through New Partnerships, Broaden Funding Base for RD&D, Growing & Maintaining Public Support) 
• A standard for mCDR is still needed. Evidence of a move towards a standard for seaweed can be seen in Verra's Seascape Carbon Initiative.

[post_title] => Building a Seaweed Carbon Market [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => building-a-seaweed-carbon-market [to_ping] => [pinged] => [post_modified] => 2024-04-17 20:50:30 [post_modified_gmt] => 2024-04-17 20:50:30 [post_content_filtered] => [post_parent] => 1669 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/development-gaps-and-needs/building-a-seaweed-carbon-market/ [menu_order] => 3 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 1817 [post_author] => 4 [post_date] => 2021-07-16 18:32:56 [post_date_gmt] => 2021-07-16 18:32:56 [post_content] =>

While interests and awareness amongst researchers and technologists is growing (i.e., Pessarrodona et al., 2023; DeAngelo et al., 2022; Troell et al., 2024), public awareness and support remain low. Many of the obstacles and needs around building and maintaining public support are not specific to macroalgal cultivation and sequestration, but there are a few points of interest specific to macroalgal cultivation pathways (Growing & Maintaining Public Support):

• Industrial-scale farms could have a negative public connotation (e.g. corn fields/monoculture in the ocean)
• If genetically modified macroalgae were to be used to increase cultivation yields and sequestration potential, especially in the context of industrial-scale macroalgae farms, that might be perceived negatively by the public given public views on genetically modified organisms 
• Public perceptions of sinking macroalgal may differ from perceptions about conversion of cultivated macroalgae into high value bio products

[post_title] => Public Awareness and Support Are Low [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => public-awareness-and-support-are-low [to_ping] => [pinged] => [post_modified] => 2024-04-17 21:00:51 [post_modified_gmt] => 2024-04-17 21:00:51 [post_content_filtered] => [post_parent] => 1669 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/development-gaps-and-needs/public-awareness-and-support-are-low/ [menu_order] => 4 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 2114 [post_author] => 4 [post_date] => 2021-07-19 20:02:29 [post_date_gmt] => 2021-07-19 20:02:29 [post_content] =>

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 (van der Molen et al., 2018; Coastal Dynamics Laboratory)
• 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.

[post_title] => Develop New Modeling Tools to Support Design and Evaluation [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => develop-new-modeling-tools-to-support-design-and-evaluation [to_ping] => [pinged] => [post_modified] => 2024-04-18 23:54:35 [post_modified_gmt] => 2024-04-18 23:54:35 [post_content_filtered] => [post_parent] => 549 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/first-order%e2%80%a8-priorities/develop-new-modeling-tools-to-support-design-and-evaluation/ [menu_order] => 0 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 2116 [post_author] => 4 [post_date] => 2021-07-19 20:02:42 [post_date_gmt] => 2021-07-19 20:02:42 [post_content] =>

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

  Work on this Priority:

• "Answering Critical Questions About Sinking Macroalgae for Carbon Dioxide Removal" (2022) {{1}}

[post_title] => Accelerate Design and Permitting of Controlled Field Trials [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => accelerate-design-and-permitting-of-controlled-field-trials [to_ping] => [pinged] => [post_modified] => 2023-08-02 14:41:00 [post_modified_gmt] => 2023-08-02 14:41:00 [post_content_filtered] => [post_parent] => 549 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/first-order%e2%80%a8-priorities/accelerate-design-and-permitting-of-controlled-field-trials/ [menu_order] => 1 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 2118 [post_author] => 4 [post_date] => 2021-07-19 20:02:57 [post_date_gmt] => 2021-07-19 20:02:57 [post_content] =>

Specific field experiments around the impacts of sinking seaweed in the deep ocean are urgently needed. (Visit the mCDR Field Trial Database for the latest information on current field experiments.) 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 (See partnership between Ocean Networks Canada and Running Tide)
• Develop a standardized list of biological indicators to measure during field trials to facilitate intercomparison between field trials (See Verra's Seascape Carbon Initiative.)
• 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}}, 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.

  [post_title] => Measure the Scale and Impacts of CDR via Macroalgae Sinking [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => measure-the-scale-and-impacts-of-cdr-via-macroalgae-sinking [to_ping] => [pinged] => [post_modified] => 2024-04-18 17:03:05 [post_modified_gmt] => 2024-04-18 17:03:05 [post_content_filtered] => [post_parent] => 549 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/first-order%e2%80%a8-priorities/measure-the-scale-and-impacts-of-cdr-via-macroalgae-sinking/ [menu_order] => 2 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 2120 [post_author] => 4 [post_date] => 2021-07-19 20:03:38 [post_date_gmt] => 2021-07-19 20:03:38 [post_content] =>

A new suite of durable, seagoing technologies are needed to support macroalgae CDR RD&D. Technology development needs include: 

[post_title] => Develop New In-Water Tools for Autonomous CDR Operations [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => develop-new-in-water-tools-for-autonomous-cdr-operations [to_ping] => [pinged] => [post_modified] => 2023-08-08 16:33:38 [post_modified_gmt] => 2023-08-08 16:33:38 [post_content_filtered] => [post_parent] => 549 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/first-order%e2%80%a8-priorities/develop-new-in-water-tools-for-autonomous-cdr-operations/ [menu_order] => 3 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 2122 [post_author] => 4 [post_date] => 2021-07-19 20:03:49 [post_date_gmt] => 2021-07-19 20:03:49 [post_content] =>

Standardized methodologies from third parties to verify uptake of atmospheric CO₂ resulting from macroalgae carbon sequestration will ultimately need to be developed to enable trading of carbon removal credits. Key first steps to support development of these protocols include:

[post_title] => Develop CDR Monitoring and Verification Protocols [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => develop-cdr-monitoring-and-verification-protocols [to_ping] => [pinged] => [post_modified] => 2023-08-02 14:41:35 [post_modified_gmt] => 2023-08-02 14:41:35 [post_content_filtered] => [post_parent] => 549 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/first-order%e2%80%a8-priorities/develop-cdr-monitoring-and-verification-protocols/ [menu_order] => 4 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 2124 [post_author] => 4 [post_date] => 2021-07-19 20:04:04 [post_date_gmt] => 2021-07-19 20:04:04 [post_content] =>

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

• Integrated multi-trophic aquaculture (García et al., 2020): 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 need 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 permits.

[post_title] => Accelerate RD&D Through New Partnerships [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => accelerate-rdd-through-new-partnerships [to_ping] => [pinged] => [post_modified] => 2024-04-18 23:56:22 [post_modified_gmt] => 2024-04-18 23:56:22 [post_content_filtered] => [post_parent] => 549 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/first-order%e2%80%a8-priorities/accelerate-rdd-through-new-partnerships/ [menu_order] => 5 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 2126 [post_author] => 4 [post_date] => 2021-07-19 20:04:16 [post_date_gmt] => 2021-07-19 20:04:16 [post_content] =>

Injection of significant funding is critical to move forward needed RD&D projects for CDR generally, for ocean-based CDR, and for macroalgae CDR specifically.  In addition to national and subnational governmental support that is vitally needed and has been outlined in the Expanding Finance and Investment road map, additional stakeholders that need to be engaged include: 

[post_title] => Broaden Funding Base for RD&D [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => broaden-funding-base-for-rdd [to_ping] => [pinged] => [post_modified] => 2023-08-02 14:42:17 [post_modified_gmt] => 2023-08-02 14:42:17 [post_content_filtered] => [post_parent] => 549 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/first-order%e2%80%a8-priorities/broaden-funding-base-for-rdd/ [menu_order] => 6 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )

WP_Post Object ( [ID] => 2128 [post_author] => 4 [post_date] => 2021-07-19 20:04:32 [post_date_gmt] => 2021-07-19 20:04:32 [post_content] =>

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 (Bertram & Merk, 2020)
• 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. 

[post_title] => Growing & Maintaining Public Support [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => growing-maintaining-public-support [to_ping] => [pinged] => [post_modified] => 2024-04-18 23:58:41 [post_modified_gmt] => 2024-04-18 23:58:41 [post_content_filtered] => [post_parent] => 549 [guid] => https://oceanvisions.org/roadmaps/macroalgae-cultivation-carbon-sequestration/first-order%e2%80%a8-priorities/growing-maintaining-public-support/ [menu_order] => 7 [post_type] => page [post_mime_type] => [comment_count] => 0 [filter] => raw )