Protection of seabed sediments in Canada's marine conservation network for potential climate change mitigation co-benefit
Abstract
Marine conserved areas (MCAs) can provide a range of ecological and socio-economic benefits, including climate change mitigation from the protection and enhancement of natural carbon storage. Canada's MCA network is expanding to encompass 30% of its Exclusive Economic Zone by 2030. At present, the network aims to integrate climate change mitigation by protecting coastal vegetated blue carbon ecosystems (saltmarsh, seagrass, kelp). Here, we argue that incorporating unvegetated seabed sediments could bring similar benefits. Seabed sediments can store and/or accumulate high densities of organic carbon, and due to their large spatial extent, contain carbon stores orders of magnitude larger than coastal vegetated habitats. We estimate that currently designated MCAs encompass only 10.8% of Canada's seabed sediment organic carbon stocks on the continental margin, and only 13.4% of areas with high carbon densities. Proposed MCAs would cover an additional 8.8% and 6.1% of total stocks and high carbon areas, respectively. We identify an additional set of high-priority seabed areas for future research and potential protection, ranking their importance based on carbon stocks, proxies for lability, and ecological/biological significance. The incorporation of seabed sediments into MCA networks could support climate change mitigation by preventing future releases of stored carbon.
1. Introduction
Due to ever-increasing human pressures on the world’s oceans (Halpern et al. 2019), marine biodiversity continues to be in significant decline globally (Brondizio et al. 2019). As part of the attempt to halt and reverse biodiversity loss, parties to the United Nations Convention on Biological Diversity (CBD) have committed (under the Kunming-Montreal Global Biodiversity Framework) to establishing ecologically-representative, well-connected, and equitably-governed networks of marine protected and conserved areas (hereafter referred to as MCAs) across 30% of their territories by 2030 (CBD 2022). MCAs have primarily been designated to conserve and/or recover declining, depleted, rare or fragile species and habitats. However, over time, the scope of MCAs has expanded to include the protection and enhancement of ecosystem services and cultural values (Roberts et al. 2003; IUCN WCPA 2018; Carr et al. 2019; Humphreys and Clark 2020). As climate change accelerates, and impacts are felt across the world (IPCC 2023), there is growing interest in the ability of MCAs to provide climate mitigation benefits, based on the protection and/or enhancement of natural carbon storage (Howard et al. 2017; Roberts et al. 2017; Jacquemont et al. 2022; Jankowska et al. 2022).
Although CO2 fixation and organic carbon storage in marine habitats are insufficient and do not act on a long enough timescale to offset fossil fuel emissions (Allen et al. 2022; Fankhauser et al. 2022; Cullenward et al. 2023; Johannessen and Christian 2023), the conservation and restoration of natural marine carbon stores could help offset historical and continued emissions of CO2 from habitat degradation and help to maintain the function of the marine environment as an ongoing carbon sink (Girardin et al. 2021; Allen et al. 2022; Gao et al. 2022; Matthews et al. 2022). This “blue carbon” potential was first described for, and continues to be focused on, coastal vegetated habitats—i.e., mangroves, saltmarshes, and seagrass meadows—which, like forests on land, can directly fix CO2, store considerable amounts of organic carbon per unit area within their underlying soils/sediments and biomass, and have undergone substantial human-induced degradation (Duarte et al. 2005; Macreadie et al. 2021; Vanderklift et al. 2022; IPCC 2023). The conservation, restoration, and improved management of other marine habitats, including macroalgal forests (Pessarrodona et al. 2023) and unvegetated seabed sediments (Avelar et al. 2017; Graves et al. 2022), are being increasingly discussed within this blue carbon framework (Vanderklift et al. 2022; Howard et al. 2023).
Seabed sediments are the ultimate carbon sink in the marine carbon cycle (Burdige 2007; Keil 2017). They are estimated to hold up to ∼2300 Gt of organic carbon in the top 1 m (Atwood et al. 2020) and accumulate an additional 126–350 Mt per year (Berner 1982; Keil 2017; Tegler et al. 2024). Due to their considerably larger spatial extent, this is approximately 7 times the global accumulation of all coastal vegetated blue carbon habitats combined, and around 200 times the carbon stock (Howard et al. 2023). Organic carbon found within unvegetated seabed sediments originates from both marine and terrestrial sources (Burdige 2007; Middelburg 2019; LaRowe et al. 2020). In total, it is estimated that around two thirds of organic carbon accumulation derives from marine primary production and one third from terrestrial sources (primarily from riverine inputs) (Burdige 2007). However, there is significant variation depending on the environmental setting. For example, about 70% of the organic carbon in deltaic sediments is estimated to be from terrestrial sources, while the organic carbon in deep sea sediments is thought to be almost entirely marine derived (Burdige 2007). Oceanic phytoplankton production and the resulting biological pump is thought to dominate marine organic carbon delivery and accumulation at the seabed (Turner 2015; Middelburg 2019); however, there is increasing evidence of lateral transport from primary production in coastal macrophyte dominated habitats (i.e., macroalgal beds, kelp forests, saltmarshes, seagrass beds, and mangroves) to unvegetated seabed sediments (Middelburg 2019; Santos et al. 2021; Pessarrodona et al. 2023).
Continental margin sediments contain the highest carbon stocks per unit area in the ocean and the fastest carbon accumulation rates, accounting for about 85% of total annual carbon accumulation at the seafloor, and about 10% of the global ocean (Berner 1982; Seiter et al. 2004; Lee et al. 2019). Fjord and deltaic sediments are known to be particular hotspots of organic carbon, in terms of both stocks and accumulation rates (Smith et al. 2015). In contrast, deep-sea sediments have the lowest carbon accumulation and stocks per unit area in the ocean (Lee et al. 2019; Atwood et al. 2020; Hayes et al. 2021); however, because they cover approximately 90% of the global seabed, deep-sea sediments are estimated to hold around 85% of total seabed sediment organic carbon standing stocks (Burdige 2007; Atwood et al. 2020). The composition of seabed sediments (i.e., the sediment type) is also known to be a strong indicator of carbon stock and accumulation rates (Burdige 2007; Diesing et al. 2021, 2024). Muddy, cohesive sediment is strongly correlated with higher organic carbon, while highly permeable, mobile, sandy sediment generally has very low organic carbon concentrations and low carbon accumulation rates (Burdige 2007; Diesing et al. 2021, 2024; Epstein et al. 2024; Smeaton et al. 2021).
Any human activity that disturbs seabed sediments has the potential to alter carbon storage (Keil 2017; Graves et al. 2022), particularly in muddy sediment (Martín et al. 2014; Black et al. 2022; Smeaton and Austin 2022; Zhang et al. 2023; Porz et al. 2024; Rooze et al. 2024). Widescale perturbation of seabed sediments could lead to significant remineralisation of stored organic carbon and reductions in further accumulation. Disruptive activities include shipping, dredging of shipping-access channels, disposal of dredge spoil, mineral extraction, bottom contact fishing, offshore energy development, deployment of cables and pipelines, and coastal development (Korpinen et al. 2013; Graves et al. 2022). These disruptive activities are most intense on continental shelves, where the distance to land and major human settlements is low, and there are fewer logistical and operational constraints (Halpern et al. 2019; Paolo et al. 2024); however, many of these activities are also expanding into the deep-sea (Victorero et al. 2018; Paulus 2021).
While the disturbance from many of these activities may be locally intense, mobile bottom fishing is by far the most pervasive and recurrent seabed disturbance—impacting at least 14% of the world’s continental shelves every 2–6 years, but varying greatly across regions, covering up to 80% of some continental shelf zones and often occurring multiple times in one year (Amoroso et al. 2018; Kroodsma et al. 2018). The impact of mobile bottom fishing is therefore expected to dominate overall human impact on seabed sediment carbon over larger spatial scales (Korpinen et al. 2013; Martín et al. 2014; Oberle et al. 2016; Keil 2017; Sala et al. 2021; Clare et al. 2023; Heinatz and Scheffold 2023). For example, a recent study estimated that global fishing activities by bottom trawling could cause considerable remineralisation of seabed sediment organic carbon stocks (Sala et al. 2021), with atmospheric emissions equivalent to ∼9%–11% of annual global emissions from land-use change (Atwood et al. 2024). There are, however, major uncertainties regarding these results, as well as the magnitude and direction of effects from other human activities and across environmental settings (Epstein et al. 2022; Hilborn and Kaiser 2022; Clare et al. 2023; Heinatz and Scheffold 2023; Hiddink et al. 2023). Even so, there are increasing calls to protect seabed sediment organic carbon stores to limit future disturbance and promote further carbon accumulation and storage (Luisetti et al. 2020; Avelar et al. 2017; Black et al. 2022; Epstein and Roberts 2023). While there is little precedent for this practice globally, a recently designated Highly Protected Marine Area in UK includes protection of “large areas of (subtidal) muddy habitats” specifically for their importance to “the storage of carbon” (DEFRA 2023).
Canada's Exclusive Economic Zone covers 7.1 million km2, an area equal to approximately 70% of its land mass and about 2% of the global ocean. The top 30 cm of seabed sediment on the continental margin is estimated to store approximately 10.9 Gt of organic carbon (Epstein et al. 2024). As of October 2024, the Canadian MCA network covers 15.4% of the marine area, with 128 designations under a variety of governing bodies and legislative acts (DFO 2023c, 2024). Canada has also committed to protecting 25% of its ocean within MCAs by 2025 and 30% by 2030 (CBD 2022; DFO 2023a, 2023c; ECCC 2024). MCAs in Canada include Marine Protected Areas, National Marine Conservation Areas, Marine Parks, National Parks with marine components, Marine National Wildlife Areas, and fisheries-focused “Other Effective area-based Conservation Measures” (OECMs or Marine Refuges) (DFO 2024). These MCAs have been designated to protect a range of benthic and pelagic marine biodiversity, as well as large-scale biogeographic features, fisheries resources, birds, terrestrial animals dependent on marine habitats, and associated sociological values (DFO 2023c, 2024). Levels of protection and implemented management measures vary, depending on the designated features, legislative acts and times of designation. However, the Canadian Federal Marine Protected Areas Protection Standard (DFO 2023b) prohibits bottom trawling, oil and gas, mining and dumping within all MCAs created after 2019.
Although the protection of habitats that capture and store carbon is defined as a potential benefit of MCA designation within Canada's National Framework for a Network of Marine Protected Areas (DFO 2011) and also listed as a criterion for inclusion within the Guidance for Recognizing Marine OECMs (DFO 2022), only vegetated blue carbon ecosystems (i.e., coastal salt marshes, seagrasses, and kelp forests) are specifically mentioned in this context (DFO 2011; Rubidge et al. 2024). Further, the department of Fisheries and Oceans Canada has a mandate to better understand ocean areas that have a high potential to absorb and store carbon and to better integrate climate impacts and vulnerability into conservation policy and management (PMO 2021). Even so, no MCA has yet been designated explicitly considering the protection of stored carbon (ECCC 2023). Combining carbon protection with climate vulnerability indices in marine protected area planning may help fill the current gap in explicit planning and management for climate change mitigation and adaptation in Canada's current, proposed and future protected areas (Keen et al. 2024).
Here, we argue that including unvegetated seabed sediment habitats within Canada's expanding MCA network could prevent future emissions of carbon from these areas and protect areas of high carbon accumulation. We also use recently published spatial estimates of organic carbon in seabed sediments across the Canadian continental margin (Epstein et al. 2024) to explore the extent to which the current and future MCA network protects this carbon store. Finally, we propose specific areas for future research that represent the highest potential for protection of existing sediment carbon stocks.
2. Comparison of blue carbon habitats in Canada
2.1. Biodiversity
Although biodiversity is not the focus of this study, its conservation is defined both within Canada (DFO 2011, 2022) and internationally (IUCN WCPA 2018) as the primary focus of MCAs, with associated ecosystem functions and services being secondary priorities. Whereas vegetated blue carbon ecosystems naturally meet expectations of biodiversity value within MCAs, due to their complex habitat provisioning and high biological diversity (Hughes 2004; Teagle et al. 2017; Ziegler et al. 2021; Unsworth et al. 2022), the diversity of unvegetated seabed sediments is generally lower. Still, seabed sediments contain a wide range of habitat types, with their community composition largely driven by depth, sediment grain-size structure, and energy state from waves and currents (Snelgrove 1999).
Seabed sediments that contain high densities of organic carbon stocks and/or accumulation rates are widely recognised to be those habitats with a sediment composition dominated by fine grain sizes (clays, silts, and muds) in relatively low energy zones of continental margins (Burdige 2007; Diesing et al. 2021; Smeaton et al. 2021; Epstein et al. 2024). Such subtidal mud habitats have a unique, diverse and often relatively fragile species assemblage dominated by burrowing infauna and epifauna, as well as the presence of a range of mobile vertebrate and invertebrate species, many of which have commercial value (Snelgrove 1999). In Canada, examples of biodiverse subtidal mud habitats include dense sea pen aggregations in the Laurentian Channel (Miatta and Snelgrove 2021), a range of commercially exploited groundfish populations on the British Columbian (BC) shelf (Thompson et al. 2023), a highly diverse assemblage of burrowing polychaetes, bivalves, crustaceans, and echinoderms in the Salish Sea (Burd et al. 2008), deep-water bamboo coral forests in the Arctic (Neves et al. 2015), and large snow crab and American lobster populations in the Northwest Atlantic (Bianchi et al. 2023). For this reason, subtidal mud habitats are already included in some current MCAs, such as the Laurentian Channel MPA, the Northeast Newfoundland Slope Closure, and the Tarium Niryutait MPA (DFO 2024). Subtidal mud habitats are also expected to be included in new designations, primarily due to the goal of building a representative MPA network (Sheppard 2013; Martone et al. 2021); however, they could also be included for their carbon protection value.
2.2. Scale of organic carbon storage
Due to their large spatial extent, seabed sediments of Canada's continental margin likely represent a carbon store over two orders of magnitude larger than that of all of Canada's saltmarsh, seagrass, and kelp combined (Table 1) (Prentice et al. 2020; Rabinowitz and Andrews 2022; Christensen and O'Connor 2023; Kelly et al. 2023; Epstein et al. 2024). On a per-unit-area basis, estimated median carbon stocks in seabed sediments (2.3 kg m−2) (Epstein et al. 2024) are higher than those of intertidal seagrass sediments (Christensen and O'Connor 2023) and lower than those of saltmarsh soils (Kelly et al. 2023), (Fig. 1, Table S1). Compared to terrestrial ecosystems, which are more widely assumed to have a role in natural climate solutions, the total organic carbon stock of Canada's continental margin seabed sediments is about half of that found in forest biomass, and about one sixth of that in terrestrial soils (Table 1) (Sothe et al. 2022). On a per-unit-area basis, seabed sediments contain median carbon stocks around two to three times lower than terrestrial soils and forest vegetation (Fig. 1, Table S1) (Rapalee et al. 1998; Liu et al. 2002). However, the carbon stock in marine sediment is not distributed uniformly, with an estimated range of < 0.001–58.4 kg m−3 (Epstein et al. 2024). Hotspots of high carbon stock (i.e., 16.8 to 58.4 kg of organic carbon per m3—see Supplementary Materials), contain median areal stocks about 33% higher than those of forest vegetation, and about 72% and 75% those of saltmarsh and terrestrial soils, respectively (Fig. 1, Table S1). These hotspots—predominantly found in the Canadian Pacific and Atlantic regions within near-coast fjords, inlets, and bays as well some troughs and channels further offshore—cover only around 1.6% of the continental margin (Fig. 3 and S1). This presents the opportunity to protect a significant amount of carbon in only a small area of seafloor (Table S1).
Fig. 1.
Table 1.
| Seabed sediments | Vegetated blue carbon | Terrestrial | |||||
|---|---|---|---|---|---|---|---|
| All | High carbon areas | Saltmarsh soils | Seagrass sediments | Kelp forests | Soils | Forest vegetation | |
| Extent (km2) | 4489 235a | 71 922a | 3602b | 1304c | 18 612d | 8584 156e | 4451 624e |
| Approximate total OC stock (Gt) | 10.4 | 0.40 | 0.03 | 0.002 | NA | 63.6 | 18.7 |
Note: Values calculated by multiplying relevant median values from Fig. 1/Table S1 with estimated extent from the table.
a
Continental margin only—Epstein et al. (2024).
2.3. Carbon benefits from protection
The protection of seabed sediments, along with saltmarsh, seagrass meadows, and kelp habitats within MCAs could provide two main carbon-specific climate benefits: (1) increased organic carbon accumulation rates and stocks from the removal of anthropogenic disturbances; and (2) the avoided loss of soil/sediment organic carbon stocks which would have otherwise been remineralised into inorganic compounds (Adame et al. 2021; Macreadie et al. 2021; Campbell et al. 2022; Vanderklift et al. 2022; Verra 2021). The first component can be, theoretically, simply quantified using a before–after protection comparison; with a net positive change in carbon stock and/or accumulation rate when compared to nearby unprotected reference sites representing a carbon benefit from protection. Removing human disturbance to seabed sediments may be expected to increase carbon accumulation rates by limiting the resuspension of settled matter and reducing oxygen exposure. However, the direction and magnitude of effects under different environmental settings and anthropogenic pressures is still uncertain and requires further research (Martín et al. 2014; Keil 2017; De Borger et al. 2021; Epstein et al. 2022; Zhang et al. 2023,2024).
Quantifying the avoided emissions resulting from protecting sediment carbon stocks is highly complex. There is a need to estimate (1) the proportion of the stock that would have been disturbed, extracted or eroded if not put under additional protection, but also (2) the proportion of this fraction that would have been remineralised back to inorganic compounds rather than reburied or relocated elsewhere, and (3) the proportion of labile carbon that would have been remineralised within the sediment in the absence of disturbance (Lovelock et al. 2017; Verra 2020; Epstein et al. 2022). This is especially challenging, as for any given disturbance and environmental setting there may be different changes in remineralisation rates both in situ within the sediment and ex situ from resuspension of sediment stores into the water column (Epstein et al. 2022; Zhang et al. 2023, 2024). Further, once in the water column, the fate of resuspended organic carbon becomes extremely difficult to track, with different proportions being redeposited, transported, consumed or remineralised (Lovelock et al. 2017; Epstein et al. 2022; Zhang et al. 2024).
Although sufficient evidence is not yet available to estimate the proportion of seabed sediment carbon stocks which would be expected to be remineralised following disturbance under different environmental settings (Epstein et al. 2022; Hiddink et al. 2023), new frameworks are starting to be developed (Verra 2023). Contributing evidence could include biogeochemical models, such as those that have estimated components of these emissions from resuspension and increased oxygen exposure to sediments as a result of mobile bottom fishing (Luisetti et al. 2019; De Borger et al. 2021; Sala et al. 2021; Zhang et al. 2023, 2024; Porz et al. 2024). There is also emerging evidence that the geographic setting and sediment type of seabed sediments may strongly influence the reactivity of stored organic carbon and therefore its risk to remineralisation if disturbed, with muddier sediments closer to shore suggested to be most vulnerable (Black et al. 2022; Epstein et al. 2022; Smeaton and Austin 2022; Zhang et al. 2023a, 2024; Rooze et al. 2024). Overall, the scale of seabed carbon remineralisation is expected to be determined by the intensity and frequency of disturbance, the reactivity/lability of the organic carbon and the biotic and abiotic conditions of the pelagic and benthic environment (Arndt et al. 2013; Middelburg 2019; LaRowe et al. 2020; Black et al. 2022).
While the calculation of the net carbon benefit from protection of seabed sediments remains highly uncertain and requires further research (Epstein et al. 2022; Hiddink et al. 2023), there are many similar uncertainties for widely-accepted vegetated blue carbon habitats that are already proposed to be included within Canada's MCA network. For example, in kelp habitats, there is limited evidence that designation within MCAs or protection from human pressures leads to higher carbon accumulation in long-term carbon stores (Pessarrodona et al. 2023; Filbee-Dexter et al. 2024); and, while there is a range of evidence that removing pressures from saltmarsh and seagrass can increase carbon accumulation rates (e.g., Macreadie et al. 2015, 2017; Muenzel and Martino 2018; Dahl et al. 2022), the effects in different settings are not uniform in magnitude or direction (e.g., Harvey et al. 2019; Spivak et al. 2019; Lafratta et al. 2020; Dahl et al. 2022). Additionally, in several global syntheses on vegetated blue carbon habitats, a range of coarse values had to be used to cover the large estimated uncertainties regarding the expected proportion of soil/sediment carbon stocks that would be remineralised if they were disturbed or not put under protection (e.g., Pendleton et al. 2012; Siikamäki et al. 2013; Griscom et al. 2017; Lovelock et al. 2017; Macreadie et al. 2021; Zeng et al. 2021). Further, when compared to the terrestrial and coastal habitats, unvegetated seabed sediments are at lower risk from large climate-driven disturbances, i.e., wildfires, heatwaves, and sea-level rise, which are expected to increase under all potential future climate scenarios and can result in the wide-scale loss of stored carbon (Zhao et al. 2021; Williamson and Gattuso 2022). The protection of seabed sediments is therefore more likely to result in carbon benefits over climate-relevant timespans (Matthews et al. 2022; Johannessen and Christian 2023).
3. Protection of seabed sediment carbon in Canada's current and proposed MCA network
Protecting seabed sediments would preserve both their standing carbon stocks and their future accumulation potential. In the following spatial analyses, we concentrate on carbon stocks alone, primarily due to a lack of spatial data on seabed sediment carbon accumulation rates, but also because of the larger potential carbon benefit from protecting stocks and the more immediate outcome of emission avoidance rather than any additional carbon burial/removal which would occur over longer timelines and be more uncertain (CCA 2022; Sala et al. 2021) (Table 1). We estimate (as of February 20204) that Canada's designated MCAs (see Supplementary Material for methods) encompass only about 10.8% of the country’s seabed sediment organic carbon stocks on the continental margin, equivalent to 1.17 Gt within the top 30 cm of sediment (uncertainty range 0.75–1.73 Gt) (Fig. 2). The areas of the continental margin with the highest organic carbon stocks (>16.8 kg m−3) are principally restricted to coastal and shelf areas of BC and the Canadian Atlantic (Fig. 3), with just 1.0% in Arctic regions (Fig. S1). Designated MCAs cover only 13.4% of the high-carbon areas (Fig. 3, Fig. S1). MCAs that encompass significant areas of high carbon sediments include those within the Laurentian Channel, the Emerald Basin Sponge Conservation Area on the Scotian Shelf, and the Gitxaala Nii Luutiksm/Kitkatla Conservancy Protected Area and Gwaii Haanas National Marine Conservation Area Reserve & Haida Heritage Site in northern BC (Fig. 3).
Fig. 2.
Fig. 3.
Although planning processes, consultations and boundary decisions are still in progress, the best available data on current proposed and potential MCAs for contribution to Canada's targets to 2025 or beyond (as of February 2024 - see Supplementary Material) indicate that, if designated, these areas would provide protection to an additional estimated 8.8% of total continental margin carbon stocks (0.95 Gt; uncertainty range 0.62–1.39 Gt) (Fig. 2), taking the total proportion under protection to 19.6%. This includes a further 6.1% of high carbon areas, which are primarily encompassed within the proposed Northern BC Shelf Bioregion network, the Southern Strait of Georgia and the Inner Bay of Fundy, thus leading to 19.5% of the high carbon areas being covered by designated and proposed/potential MCAs (Fig. 3, Fig S1). Even though these MCAs were (or will be) designated solely for biodiversity conservation, the management measures adopted will in many cases provide a co-benefit to seabed sediment carbon protection, particularly if they overlap with high-carbon areas. Periodic monitoring of carbon stocks and accumulation rates would need to be implemented within MCAs if net carbon benefits want to be estimated and reported by managers to further justify site designations.
4. Priority areas for research and potential future spatial protections
We identify 274 priority areas that encompass the majority of the high carbon zones outside current and planned MCAs (Fig. 4; see Supplementary Materials for further details). These priority areas were then ranked upon their: (1) mean carbon stock (including estimated uncertainty), (2) total carbon stock (including estimated uncertainty), (3) estimated mean mud content, (4) distance to shore (with muddier areas closer to shore prioritised due to the organic carbon being potentially of higher reactivity and vulnerability) (Smeaton et al. 2021; Black et al. 2022; Zhang et al. 2024), and (5) the proportion of the area which lies within Ecologically and Biologically Significant Areas (DFO 2021) (see Supplementary Materials). The sum of these 5 rankings was taken as a general metric for potential overall priority for future research and precautionary protection (Fig. 4). Most of the highest priority areas (ranks 1–10) were situated in bioregions of BC (Table 2), including the Queen Charlotte Strait and northern Salish Sea, as well as many of the fjords and inlets on the west coast of Vancouver Island and mainland BC (Fig. 4, Fig. S2). Priority areas with the next highest rankings (11–30) were largely within the Atlantic bioregions (Table 2), specifically in Placentia, Passamaquoddy, Mahone and Trinity bays, parts of the Laurentian Channel and the northern and southern ends of Scotian Shelf (Fig. 4, Fig. S2). It could be equally relevant to rank areas on a subset of these factors, and/or individual characteristics alone, e.g., carbon density. Individual rankings and estimated carbon values are presented in the Supplementary Material and supporting data products to facilitate alternative ranking schemes.
Fig. 4.
Table 2.
| All | British Columbia/Pacific | Atlantic | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Strait of Georgia | Southern BC Shelf | Northern BC Shelf | Estuary and Gulf of St Law’ | Scotian Shelf | Newfoundland and Labrador | |||||||||
| PA rank | Area (km2) | % (by area) | Count | % (by area) | Count | % (by area) | Count | % (by area) | Count | % (by area) | Count | % (by area) | Count | % (by area) |
| 1–10 | 10 564 | 11.4 | 1 | 4.6 | 1 | 0.3 | 7 | 5.3 | 0 | 0.0 | 0 | 0.0 | 1 | 1.3 |
| 11–20 | 15 555 | 16.8 | 0 | 0.0 | 1 | 0.1 | 4 | 1.6 | 2 | 5.4 | 2 | 2.2 | 3 | 7.7 |
| 21–30 | 12 ,769 | 13.8 | 0 | 0.0 | 1 | 0.2 | 4 | 0.3 | 1 | 4.9 | 3 | 3.1 | 4 | 5.4 |
| 31–40 | 9297 | 10.1 | 0 | 0.0 | 1 | 7.8 | 6 | 0.8 | 1 | 0.3 | 2 | 0.3 | 1 | 0.9 |
| 41–50 | 15 649 | 16.9 | 1 | 0.1 | 2 | 0.3 | 2 | 0.2 | 4 | 4.0 | 2 | 10.6 | 2 | 1.7 |
| 50–100 | 15 057 | 16.3 | 3 | 0.3 | 6 | 0.6 | 15 | 1.0 | 10 | 2.3 | 6 | 4.2 | 11 | 8.0 |
| 101–274 | 13 507 | 14.6 | 7 | 0.1 | 5 | 0.1 | 15 | 0.5 | 50 | 2.6 | 47 | 5.8 | 52 | 5.4 |
Note: The number of priority areas in each bioregion (Count) is shown along with proportion of the coverage by that subset when compared to the area covered by all priority areas across the continental margin (% by area). The sum of the counts for a particular ranking level may be larger than size of the range of ranks due to priority areas overlapping multiple bioregions. The locations and boundaries of bioregions are shown in Fig. S2.
Data gaps which should be addressed prior to designation include site-specific spatial mapping of seabed sediment habitats and in situ measurements of organic carbon stocks and accumulation rates to confirm the presence and distribution of high-density carbon stocks or potential for future accumulation, where data are lacking (e.g., Brenan et al. 2024). Data on the composition and lability of the organic carbon stocks would also provide information on the likelihood of remineralisation if disturbed, compared with the rate of remineralisation in undisturbed sediments (Graves et al. 2022; Smeaton and Austin 2022).
Although most of the Canadian continental margin is situated within the Arctic, the best available data suggest that these regions do not contain especially high carbon densities outside of current or proposed MCAs; they are therefore not selected as priority areas in this study (Fig. S1). Emerging research does, however, suggest that as sea ice extent and thickness reduce as a result of climate change, carbon accumulation in seabed sediments of the polar regions could increase due to higher levels of primary production and reduced disturbance to the seafloor from ice scour (Barnes 2018; Armstrong et al. 2020; Barnes et al. 2021; Attard et al. 2024). In the Antarctic this has been proposed as a potentially important negative feedback mechanism to anthropogenic climate change (Barnes et al. 2021; Bax et al. 2021). Evidence from Arctic regions, however, has shown that these changes are not uniform in magnitude, with the opposite effect also reported (Macdonald et al. 2015; Faust et al. 2020; Souster et al. 2020; März et al. 2022; Attard et al. 2024; Sen et al. 2024).
Even so, reduced sea ice extent is expected to lead to increased human activities in the Arctic Ocean, with potential for increased seafloor disturbance and, therefore, perturbation of organic carbon stores and accumulation (Keil 2017; Fauchald et al. 2021; Huntington et al. 2022; März et al. 2022). Precautionary protection could be considered for seabed sediments within the Arctic that have relatively high carbon densities and that also currently lie outside of the Canadian MCA network, such as the Foxe Basin, the Beaufort Shelf and Canadian Arctic fjords (Fig. 2) (Smith et al. 2015). As discussed above, significant data gaps remain, with respect to fully quantifying the organic carbon stocks and accumulation rates, the risk of disturbance, and the vulnerability of resuspended and disturbed organic carbon to remineralisation.
Rather than focusing only on the precautionary protection of seabed sediments, by also including data on both current and projected human disturbance levels in high carbon areas, prioritisations could be made based on the potential for carbon benefits from removal and/or prohibition of human activities. To fully calculate potential carbon benefits from protection, site-specific information would be required on the current and future levels of sediment disturbance from each human stressor as well as their combined net effects on carbon stocks and accumulation rates (Verra 2020; Epstein et al. 2022). Further, when spatial restrictions are placed on human activities or marine industries there is the potential for effort displacement, whereby a proportion, or the entirety of a prohibited activity simply moves to a new location (Vaughan 2017). The potential for activity displacement and the net effects on total seabed sediment carbon disturbance, stocks and accumulation rates should also be incorporated where possible (Epstein and Roberts 2022). Detailed data of this resolution are lacking at both country-wide and site-specific scales and should be a priority for future research. Additionally, the prohibition or exclusion of human activities also necessitates the consideration of numerous sociological, economic and ecological costs and benefits (Davis et al. 2019; Oyafuso et al. 2020). The potential effects on seabed sediment carbon could become just one component of the analysis and prioritisation processes within MCA planning and management.
5. Conclusion
The protection of organic carbon storage in the biosphere is a key component to limiting global temperature rise from anthropogenic climate change (Girardin et al. 2021; Matthews et al. 2022). Increasing spatial protection of marine habitats and species will continue to 2030 and potentially beyond (CBD 2022; DFO 2023c). These MCAs will incorporate a variety of features of ecological and biological importance, including established vegetated blue carbon habitats which are frequently expected to provide climate change mitigation co-benefits (DFO 2011, 2022; Howard et al. 2017; Roberts et al. 2017; Jankowska et al. 2022; CBD 2022). Including high-carbon areas of unvegetated seabed sediments in MCA networks would protect carbon stocks as well as unique, diverse and often fragile ecosystems. While our work focuses on the Canadian MCA network, the patterns and logic discussed above are expected to be applicable to many other locations globally. Although more research is needed to quantify carbon stocks and accumulation rates more accurately, and reduce uncertainty into the magnitude and direction of effects from human disturbance and seabed protection, the incorporation of these habitats into MCA networks would represent a precautionary approach while further evidence is gathered especially when focusing on seabed areas with the highest carbon densities, accumulation rates and vulnerabilities.
Acknowledgements
We greatly appreciate advice and participation in this work from partners including various members of Fisheries and Oceans Canada (DFO) and Oceans North. We thank two anonymous reviewers for their constructive review of the manuscript.
References
Adame M.F., Connolly R.M., Turschwell M.P., Lovelock C.E., Fatoyinbo T., Lagomasino D., et al. 2021. Future carbon emissions from global mangrove forest loss. Global Change Biology, 27(12): 2856–2866.
Allen M.R., Friedlingstein P., Girardin C.A.J., Jenkins S., Malhi Y., Mitchell-Larson E., et al. 2022. Net zero: science, origins, and implications. Annual Review of Environment and Resources, 47(1): 849–887.
Amoroso R.O., Pitcher C.R., Rijnsdorp A.D., McConnaughey R.A., Parma A.M., Suuronen P., et al. 2018. Bottom trawl fishing footprints on the world's continental shelves. Proceedings of the National Academy of Sciences of the U.S.A. 115(43): E10275–E10282.
Armstrong S., Hull S., Pearson Z., Kay S., Wilson R. 2020. Estimating the carbon sink potential of the Welsh marine environment. Natural Resources Wales Evidence Report, 428, P21018–P20072.
Arndt S., Jørgensen B.B., LaRowe D.E., Middelburg J.J., Pancost R.D., Regnier P. 2013. Quantifying the degradation of organic matter in marine sediments: a review and synthesis. Earth-Science Reviews, 123, 53–86.
Attard K., Singh R.K., Gattuso J.-P., Filbee-Dexter K., Krause-Jensen D., Kühl M., et al. 2024. Seafloor primary production in a changing Arctic Ocean. Proceedings of the National Academy of Sciences, 121(11): e2303366121.
Atwood T.B., Romanou A., DeVries T., Lerner P.E., Mayorga J.S., Bradley D., et al. 2024. Atmospheric CO2 emissions and ocean acidification from bottom-trawling. Frontiers in Marine Science, 10. Available from https://www.frontiersin.org/articles/10.3389/fmars.2023.1125137.
Atwood T.B., Witt A., Mayorga J., Hammill E., Sala E. 2020. Global patterns in marine sediment carbon stocks. Frontiers in Marine Science, 7, 165.
Avelar S., van der Voort T.S., Eglinton T.I. 2017. Relevance of carbon stocks of marine sediments for national greenhouse gas inventories of maritime nations. Carbon Balance and Management, 12(1): 10.
Barnes D.K.A. 2018. Blue carbon on polar and subpolar seabeds. Carbon Capture, Utilization and Sequestration.
Barnes D.K.A., Sands C.J., Paulsen M.L., Moreno B., Moreau C., Held C., et al. 2021. Societal importance of Antarctic negative feedbacks on climate change: blue carbon gains from sea ice, ice shelf and glacier losses. The Science of Nature, 108(5): 43.
Bax N., Sands C.J., Gogarty B., Downey R.V., Moreau C.V.E., Moreno B., et al. 2021. Perspective: increasing blue carbon around Antarctica is an ecosystem service of considerable societal and economic value worth protecting. Global Change Biology, 27(1): 5–12.
Berner R.A. 1982. Burial of organic carbon and pyrite sulfur in the modern ocean; its geochemical and environmental significance. American Journal of Science, 282(4): 451–473.
Bianchi T.S., Brown C.J., Snelgrove P.V.R., Stanley R.R.E., Cote D., Morris C. 2023. Benthic invertebrates on the move: a tale of ocean warming and sediment carbon storage. Limnology and Oceanography Bulletin, 32(1): 1–5.
Black K.E., Smeaton C., Turrell W.R., Austin W.E.N. 2022. Assessing the potential vulnerability of sedimentary carbon stores to bottom trawling disturbance within the UK EEZ. Frontiers in Marine Science, 9, 892892.
Brenan C., Kienast M., Maselli V., Algar C.K., Misiuk B., Brown C.J. 2024. Seafloor sediment characterization improves estimates of organic carbon standing stocks: an example from the Eastern Shore Islands, Nova Scotia, Canada. Biogeosciences, 21(20): 4569–4586.
Brondizio E.S., Settele J., Diaz S., Ngo H.T. 2019. Global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.
Burd B.J., Barnes P.A.G., Wright C.A., Thomson R.E. 2008. A review of subtidal benthic habitats and invertebrate biota of the Strait of Georgia, British Columbia. Benthic Processes, Organic Carbon Cycling and Contaminants in the Strait of Georgia, Canada, 66, S3–S38.
Burdige D.J. 2007. Preservation of organic matter in marine sediments: controls, mechanisms, and an imbalance in sediment organic carbon budgets? Chemical Reviews, 107(2): 467–485.
Campbell A.D., Fatoyinbo L., Goldberg L., Lagomasino D. 2022. Global hotspots of salt marsh change and carbon emissions. Nature, 612(7941): 701–706.
Carr M.H., White J.W., Saarman E., Lubchenco J., Milligan K., Caselle J.E. 2019. Marine protected areas exemplify the evolution of science and policy. Oceanography, 32(3): 94–103.
CBD. 2022. Kunming-Montreal Global Biodiversity Framework (GBF). Fifteeth Meeting of the Conference of the Parties to the Conventrion on Biological Diversity, 2, CBD/COP/15/L.25.
CCA. 2022. Nature-based climate solutions. Council of Canadian academies, the expert panel on Canada's carbon sink potential. 290pp.
Christensen M.S., O'Connor M.I. 2023. Estimating blue carbon storage capacity of Canada's eelgrass beds. University of British Columbia. M.Sc. thesis, 81pp.
Clare M.A., Lichtschlag A., Paradis S., Barlow N.L.M. 2023. Assessing the impact of the global subsea telecommunications network on sedimentary organic carbon stocks. Nature Communications, 14(1): 2080.
Cullenward D., Badgley G., Chay F. 2023. Carbon offsets are incompatible with the Paris Agreement. One Earth, 6(9): 1085–1088.
Dahl M., Ismail R., Braun S., Masqué P., Lavery P.S., Gullström M., et al. 2022. Impacts of land-use change and urban development on carbon sequestration in tropical seagrass meadow sediments. Marine Environmental Research, 176, 105608.
Davis K.J., Vianna G.M.S., Meeuwig J.J., Meekan M.G., Pannell D.J. 2019. Estimating the economic benefits and costs of highly-protected marine protected areas. Ecosphere, 10(10): e02879.
De Borger E., Tiano J., Braeckman U., Rijnsdorp A.D., Soetaert K. 2021. Impact of bottom trawling on sediment biogeochemistry: a modelling approach. Biogeosciences, 18, 2539–2557.
DEFRA. 2023. Highly Protected Marine Areas (HPMAs). Department for Environment Food & Rural Affairs—Policy Paper. Available from https://www.gov.uk/government/publications/highly-protected-marine-areas/highly-protected-marine-areas-hpmas.
DFO. 2011. National framework for Canada's network of marine protected areas. Fisheries and Oceans Canada, Government of Canada, Ottawa. 31pp.
DFO. 2021. Ecologically and biologically significant areas. Fisheries and Oceans Canada. Available from https://open.canada.ca/data/en/dataset/d2d6057f-d7c4-45d9-9fd9-0a58370577e0.
DFO. 2022. Guidance for recognizing marine other effective area-based conservation measures. Fisheries and Oceans Canada, Government of Canada, Ottawa. 51pp.
DFO. 2023a. Canada's path to 25 per cent ocean protection by 2025. Fisheries and Oceans Canada, Government of Canada, Ottawa. Available from https://www.canada.ca/en/fisheries-oceans/news/2023/02/canadas-path-to-25-per-cent-ocean-protection-by-2025.html.
DFO. 2023b. Federal marine protected areas protection standard. Fisheries and Oceans Canada.
DFO. 2023c. Reaching Canada's marine conservation targets. Fisheries and Oceans Canada, Government of Canada, Ottawa. Available from https://www.dfo-mpo.gc.ca/oceans/conservation/plan/index-eng.html.
DFO. 2024. Canada's marine protected and conserved areas. Fisheries and Oceans Canada, Government of Canada, Ottawa. Available from https://www.dfo-mpo.gc.ca/oceans/conservation/areas-zones/index-eng.html.
Diesing M., Paradis S., Jensen H., Thorsnes T., Bjarnadóttir L.R., Knies J. 2024. Glacial troughs as centres of organic carbon accumulation on the Norwegian continental margin.Communications Earth & Environment, 5, 327.
Diesing M., Thorsnes T., Bjarnadóttir L.R. 2021. Organic carbon densities and accumulation rates in surface sediments of the North Sea and Skagerrak. Biogeosciences, 18(6): 2139–2160.
Duarte C.M., Middelburg J.J., Caraco N. 2005. Major role of marine vegetation on the oceanic carbon cycle. Biogeosciences, 2, 1–8.
ECCC. 2023. Canadian Protected and Conserved Areas Database. Environment and Climate Change Canada, Government of Canada. Available from https://www.canada.ca/en/environment-climate-change/services/national-wildlife-areas/protected-conserved-areas-database.html.
ECCC. 2024. Canada's 2030 nature strategy: halting and reversing biodiversity loss in Canada. Environment and Climate Change Canada, Government of Canada, ii+177pp.
Epstein G., Fuller S.D., Hingmire D., Myers P.G., Peña A., Pennelly C., Baum J.K. 2024. Predictive mapping of organic carbon stocks in surficial sediments of the Canadian continental margin. Earth System Science Data, 16(5): 2165–2195.
Epstein G., Middelburg J.J., Hawkins J.P., Norris C.R., Roberts C.M. 2022. The impact of mobile demersal fishing on carbon storage in seabed sediments. Global Change Biology, 28(9): 2875–2894.
Epstein G., Roberts C.M. 2022. Identifying priority areas to manage mobile bottom fishing on seabed carbon in the UK. PLOS Climate, 1(9): e0000059.
Epstein G., Roberts C.M. 2023. Does biodiversity-focused protection of the seabed deliver carbon benefits? A U.K. case study. Conservation Letters, 16(1): e12929.
Fankhauser S., Smith S.M., Allen M., Axelsson K., Hale T., Hepburn C., et al. 2022. The meaning of net zero and how to get it right. Nature Climate Change, 12(1): 15–21.
Fauchald P., Arneberg P., Debernard J.B., Lind S., Olsen E., Hausner V.H. 2021. Poleward shifts in marine fisheries under Arctic warming. Environmental Research Letters, 16(7): 074057.
Faust J.C., Stevenson M.A., Abbott G.D., Knies J., Tessin A., Mannion I., et al. 2020. Does Arctic warming reduce preservation of organic matter in Barents Sea sediments? Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 378(2181): 20190364.
Filbee-Dexter K., Starko S., Pessarrodona A., Wood G., Norderhaug K.M., Piñeiro-Corbeira C., Wernberg T. 2024. Marine protected areas can be useful but are not a silver bullet for kelp conservation. Journal of Phycology, 60(2): 203–213.
Gao G., Beardall J., Jin P., Gao L., Xie S., Gao K. 2022. A review of existing and potential blue carbon contributions to climate change mitigation in the Anthropocene. Journal of Applied Ecology, 59(7): 1686–1699.
Girardin C.A., Jenkins S., Seddon N., Allen M., Lewis S.L., Wheeler C.E., et al. 2021. Nature-based solutions can help cool the planet—If we act now. Nature, 593(7858): 191–194.
Graves C.A., Benson L., Aldridge J., Austin W.E.N., Dal Molin F., Fonseca V.G., et al. 2022. Sedimentary carbon on the continental shelf: emerging capabilities and research priorities for blue carbon. Frontiers in Marine Science, 9, 926215.
Griscom B.W., Adams J., Ellis P.W., Houghton R.A., Lomax G., Miteva D.A., et al. 2017. Natural climate solutions. Proceedings of the National Academy of Sciences, 114(44): 11645–11650.
Halpern B.S., Frazier M., Afflerbach J., Lowndes J.S., Micheli F., O'Hara C., et al. 2019. Recent pace of change in human impact on the world's ocean. Scientific Reports, 9(1): 11609.
Harvey R.J., Garbutt A., Hawkins S.J., Skov M.W. 2019. No detectable broad-scale effect of livestock grazing on soil blue-carbon stock in salt marshes. Frontiers in Ecology and Evolution, 7. Available from https://www.frontiersin.org/articles/10.3389/fevo.2019.00151.
Hayes C.T., Costa K.M., Anderson R.F., Calvo E., Chase Z., Demina L.L., et al. 2021. Global ocean sediment composition and burial flux in the Deep Sea. Global Biogeochemical Cycles, 35(4): e2020GB006769.
Heinatz K., Scheffold M.I.E. 2023. A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea. Frontiers in Marine Science, 9. Available from https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.1068967.
Hiddink J.G., van de Velde S.J., McConnaughey R.A., De Borger E., Tiano J., Kaiser M.J., et al. 2023. Quantifying the carbon benefits of ending bottom trawling. Nature, 617(7960): E1–E2.
Hilborn R., Kaiser M.J. 2022. A path forward for analysing the impacts of marine protected areas. Nature, 607(7917): E1–E2.
Howard J., McLeod E., Thomas S., Eastwood E., Fox M., Wenzel L., Pidgeon E. 2017. The potential to integrate blue carbon into MPA design and management. Aquatic Conservation: Marine and Freshwater Ecosystems, 27, 100–115.
Howard J., Sutton-Grier A.E., Smart L.S., Lopes C.C., Hamilton J., Kleypas J., et al. 2023. Blue carbon pathways for climate mitigation: known, emerging and unlikely. Marine Policy, 156, 105788.
Hughes R.G. 2004. Climate change and loss of saltmarshes: consequences for birds. Ibis, 146(s1): 21–28.
Humphreys J., Clark R. 2020. Marine Protected Areas: Science, Policy and Management. Elsevier.
Huntington H.P., Zagorsky A., Kaltenborn B.P., Shin H.C., Dawson J., Lukin M., et al. 2022. Societal implications of a changing Arctic Ocean. Ambio, 51(2): 298–306.
IPCC. 2023. Climate change 2023: synthesis report. A Report of the Intergovernmental Panel on Climate Change. In press. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee, J. Romero (Editors)]., IPCC, Geneva, Switzerland.
IUCN WCPA. 2018. Applying IUCN's Global Conservation Standards to Marine Protected Areas (MPA). Delivering Effective Conservation Action through MPAs, to Secure Ocean Health & Sustainable Development. Gland, Switzerland, 1, 4pp.
Jacquemont J., Blasiak R., Le Cam C., Le Gouellec M., Claudet J. 2022. Ocean conservation boosts climate change mitigation and adaptation. One Earth, 5(10): 1126–1138.
Jankowska E., Pelc R., Alvarez J., Mehra M., Frischmann C.J. 2022. Climate benefits from establishing marine protected areas targeted at blue carbon solutions. Proceedings of the National Academy of Sciences, 119(23): e2121705119.
Johannessen S.C., Christian J.R. 2023. Why blue carbon cannot truly offset fossil fuel emissions. Communications Earth and Environment, 4(1): 411.
Keen L.H., Stortini C.H., Boyce D.G., Stanley R.R.E. 2024. Assessing climate change vulnerability in Canadian marine conservation networks: implications for conservation planning and resilience. FACETS, 9, 1–15.
Keil R. 2017. Anthropogenic forcing of carbonate and organic carbon preservation in marine sediments. Annual Review of Marine Science, 9(1): 151–172.
Kelly B., Currie J., Fish M., Alleway H., Baum J., Beck A., et al. 2023. Coastal blue carbon in Canada: state of knowledge. WWF Canada. Available from https://wwf.ca/wp-content/uploads/2023/06/BlueCarbon_StateofKnowledge_Report.pdf.
Korpinen S., Meidinger M., Laamanen M. 2013. Cumulative impacts on seabed habitats: an indicator for assessments of good environmental status. Marine Pollution Bulletin, 74(1): 311–319.
Kroodsma D.A., Mayorga J., Hochberg T., Miller N.A., Boerder K., Ferretti F., et al. 2018. Tracking the global footprint of fisheries. Science, 359(6378): 904–908.
Lafratta A., Serrano O., Masqué P., Mateo M.A., Fernandes M., Gaylard S., Lavery P.S. 2020. Challenges to select suitable habitats and demonstrate ‘additionality’ in Blue Carbon projects: a seagrass case study. Ocean & Coastal Management, 197.
LaRowe D.E., Arndt S., Bradley J.A., Estes E.R., Hoarfrost A., Lang S.Q., et al. 2020. The fate of organic carbon in marine sediments—new insights from recent data and analysis. Earth-Science Reviews, 204.
Lee T.R., Wood W.T., Phrampus B.J. 2019. A machine learning (kNN) approach to predicting global seafloor total organic carbon. Global Biogeochemical Cycles, 33(1): 37–46.
Liu J., Chen J.M., Cihlar J., Chen W. 2002. Net primary productivity mapped for Canada at 1-km resolution. Global Ecology and Biogeography, 11(2): 115–129.
Lovelock C.E., Atwood T., Baldock J., Duarte C.M., Hickey S., Lavery P.S., et al. 2017. Assessing the risk of carbon dioxide emissions from blue carbon ecosystems. Frontiers in Ecology and the Environment, 15(5): 257–265.
Luisetti T., Ferrini S., Grilli G., Jickells T.D., Kennedy H., Kröger S., et al. 2020. Climate action requires new accounting guidance and governance frameworks to manage carbon in shelf seas. Nature Communications, 11(1): 4599.
Luisetti T., Turner R.K., Andrews J.E., Jickells T.D., Kröger S., Diesing M., et al. 2019. Quantifying and valuing carbon flows and stores in coastal and shelf ecosystems in the UK. Ecosystem Services, 35, 67–76.
Macdonald R.W., Kuzyk Z.Z.A., Johannessen S.C. 2015. The vulnerability of Arctic shelf sediments to climate change. Environmental Reviews, 23(4): 461–479.
Macreadie P.I., Costa M.D.P., Atwood T.B., Friess D.A., Kelleway J.J., Kennedy H., et al. 2021. Blue carbon as a natural climate solution. Nature Reviews Earth and Environment, 2(12): 826–839.
Macreadie P.I., Nielsen D.A., Kelleway J.J., Atwood T.B., Seymour J.R., Petrou K., et al. 2017. Can we manage coastal ecosystems to sequester more blue carbon?- supporting information—summary of the key environmental processes influencing blue carbon sequestration in vegetated coastal habitats. Frontiers in Ecology and the Environment, 15(4): 206–213.
Macreadie P.I., Trevathan-Tackett S.M., Skilbeck C.G., Sanderman J., Curlevski N., Jacobsen G., Seymour J.R. 2015. Losses and recovery of organic carbon from a seagrass ecosystem following disturbance. Proceedings of the Royal Society B: Biological Sciences, 282(1817): 20151537.
Martín J., Puig P., Palanques A., Giamportone A. 2014. Commercial bottom trawling as a driver of sediment dynamics and deep seascape evolution in the anthropocene. Anthropocene, 7, 1–15.
Martone R.G., Robb C.K., Gale K.S.P., Frid A., McDougall C., Rubidge E. 2021. Design Strategies for the Northern Shelf Bioregional Marine Protected Area Network. Fisheries and Oceans Canada (DFO), Canadian Science Advisory Secretariat (CSAS), Research Document 2021/024. xi+156p.
März C., Freitas F.S., Faust J.C., Godbold J.A., Henley S.F., Tessin A.C., et al. 2022. Biogeochemical consequences of a changing Arctic shelf seafloor ecosystem. Ambio, 51(2): 370–382.
Matthews H.D., Zickfeld K., Dickau M., MacIsaac A.J., Mathesius S., Nzotungicimpaye C.-M., Luers A. 2022. Temporary nature-based carbon removal can lower peak warming in a well-below 2 °C scenario. Communications Earth and Environment, 3(1): 65.
McHenry J., Okamoto D.K., Filbee-Dexter K., Krumhansel K., MacGregor K.A., Hessing-Lewis M., et al. 2024. A blueprint for national assessments of the blue carbon capacity of kelp forests applied to Canadas coastline. BioRxiv, 04.05, 586816. bioRxiv.
Miatta M., Snelgrove P.VR. 2021. Benthic nutrient fluxes in deep-sea sediments within the Laurentian Channel MPA (eastern Canada): the relative roles of macrofauna, environment, and sea pen octocorals. Deep Sea Research Part I: Oceanographic Research Papers, 178, 103655.
Middelburg J.J. 2019. Marine carbon biogeochemistry: a primer for earth system scientists. Springer.
Muenzel D., Martino S. 2018. Assessing the feasibility of carbon payments and payments for ecosystem services to reduce livestock grazing pressure on saltmarshes. Journal of Environmental Management, 225, 46–61.
Neves B., de M., Edinger E., Hillaire-Marcel C., Saucier E.H., France S.C., et al. 2015. Deep-water bamboo coral forests in a muddy Arctic environment. Marine Biodiversity, 45(4): 867–871.
Oberle F.K.J., Storlazzi C.D., Hanebuth T.J.J. 2016. What a drag: quantifying the global impact of chronic bottom trawling on continental shelf sediment. Journal of Marine Systems, 159, 109–119.
Oyafuso Z.S., Leung P., Franklin E.C. 2020. Understanding biological and socioeconomic tradeoffs of marine reserve planning via a flexible integer linear programming approach. Biological Conservation, 241, 108319.
Paolo F., Kroodsma D., Raynor J., Hochberg T., Davis P., Cleary J., et al. 2024. Satellite mapping reveals extensive industrial activity at sea. Nature, 625(7993): 85–91.
Paulus E. 2021. Shedding light on deep-sea biodiversity—a highly vulnerable habitat in the face of anthropogenic change. Frontiers in Marine Science, 8. Available from https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.667048.
Pendleton L., Donato D.C., Murray B.C., Crooks S., Jenkins W.A., Sifleet S., et al. 2012. Estimating global “blue carbon” emissions from conversion and degradation of vegetated coastal ecosystems. PLoS ONE, 7(9): e43542.
Pessarrodona A., Franco-Santos R.M., Wright L.S., Vanderklift M.A., Howard J., Pidgeon E., et al. 2023. Carbon sequestration and climate change mitigation using macroalgae: a state of knowledge review. Biological Reviews.
PMO. 2021. Minister of Fisheries, Oceans and the Candaian Coast Guard Mandate Letter. Office of the Prime Minister, Canada.
Porz L., Zhang W., Christiansen N.G., Kossack J., Daewel U., Schrum C. 2024. Quantification and mitigation of bottom trawling impacts on sedimentary organic carbon stocks in the North Sea. EGUsphere, 2024, 1–48.
Prentice C., Poppe K.L., Lutz M., Murray E., Stephens T.A., Spooner A., et al. 2020. A synthesis of blue carbon stocks, sources, and accumulation rates in Eelgrass (Zostera marina) Meadows in the Northeast Pacific. Global Biogeochemical Cycles, 34(2): e2019GB006345.
Rabinowitz T., Andrews J. 2022. Valuing the Salt Marsh Ecosystem: Developing Ecosystem Accounts. Environment Accounts and Statistics Analytical and Technical Paper Series—Statistics Canada, Catalogue no. 16-001-M, 47pp.
Rapalee G., Trumbore S.E., Davidson E.A., Harden J.W., Veldhuis H. 1998. Soil carbon stocks and their rates of accumulation and loss in a boreal forest landscape. Global Biogeochemical Cycles, 12(4): 687–701.
Roberts C.M., Andelman S., Branch G., Bustamante R.H., Carlos Castilla J., Dugan J., et al. 2003. Ecological criteria for evaluating candidate sites for marine reserves. Ecological Applications, 13(sp1): 199–214.
Roberts C.M., O'Leary B.C., McCauley D.J., Cury P.M., Duarte C.M., Lubchenco J., et al. 2017. Marine reserves can mitigate and promote adaptation to climate change. Proceedings of the National Academy of Sciences of the U.S.A., 114(24): 6167–6175.
Rooze J., Zeller M.A., Gogina M., Roeser P., Kallmeyer J., Schönke M., et al. 2024. Bottom-trawling signals lost in sediment: a combined biogeochemical and modeling approach to early diagenesis in a perturbed coastal area of the southern Baltic Sea. Science of The Total Environment, 906, 167551.
Rubidge E.M., Robb C.K., Thompson P.L., McDougall C., Bodtker K.M., Gale K.S.P., et al. 2024. Evaluating the design of the first marine protected area network in Pacific Canada under a changing climate. FACETS, 9, 1–18.
Sala E., Mayorga J., Bradley D., Cabral R.B., Atwood T.B., Auber A., et al. 2021. Protecting the global ocean for biodiversity, food and climate. Nature, 592, 397–402.
Santos I.R., Burdige D.J., Jennerjahn T.C., Bouillon S., Cabral A., Serrano O., et al. 2021. The renaissance of Odum's outwelling hypothesis in ‘blue carbon’ science. Estuarine, Coastal and Shelf Science, 255, 107361.
Seiter K., Hensen C., Schröter J., Zabel M. 2004. Organic carbon content in surface sediments—Defining regional provinces. Deep Sea Research Part I: Oceanographic Research Papers, 51(12): 2001–2026.
Sen A., Molina E.J., de Freitas T.R., Hess S., Reiss H., Bluhm B.A., Renaud P.E. 2024. Benthic remineralization under future Arctic conditions and evaluating the potential for changes in carbon sequestration in warming sediments. Scientific Reports, 14(1): 23336.
Sheppard V. 2013. International Approaches to Characterizing Marine Seascapes to Achieve Representativity in MPA Network Design. Fisheries and Oceans Canada (DFO), Canadian Science Advisory Secretariat (CSAS), Research Document 2013/048, v + 20p.
Siikamäki J., Sanchirico J.N., Jardine S., McLaughlin D., Morris D. 2013. Blue carbon: coastal ecosystems, their carbon storage, and potential for reducing emissions. Environment: Science and Policy for Sustainable Development, 55(6): 14–29.
Smeaton C., Austin W.E.N. 2022. Quality not quantity: prioritizing the management of sedimentary organic matter across continental shelf seas. Geophysical Research Letters, e2021GL097481.
Smeaton C., Hunt C.A., Turrell W.R., Austin W.E.N. 2021. Marine sedimentary carbon stocks of the United Kingdom's exclusive economic zone. Frontiers in Earth Science, 9, 50.
Smith R.W., Bianchi T.S., Allison M., Savage C., Galy V. 2015. High rates of organic carbon burial in fjord sediments globally. Nature Geoscience, 8(6): 450–453.
Snelgrove P.V.R. 1999. Getting to the bottom of marine biodiversity: sedimentary habitats: ocean bottoms are the most widespread habitat on Earth and support high biodiversity and key ecosystem services. Bioscience, 49(2): 129–138.
Sothe C., Gonsamo A., Arabian J., Kurz W.A., Finkelstein S.A., Snider J. 2022. Large soil carbon storage in terrestrial ecosystems of Canada. Global Biogeochemical Cycles, 36(2): e2021GB007213.
Souster T.A., Barnes D.K.A., Hopkins J. 2020. Variation in zoobenthic blue carbon in the Arctic's Barents Sea shelf sediments. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 378(2181): 20190362.
Spivak A.C., Sanderman J., Bowen J.L., Canuel E.A., Hopkinson C.S. 2019. Global-change controls on soil-carbon accumulation and loss in coastal vegetated ecosystems. Nature Geoscience, 12(9): 685–692.
Teagle H., Hawkins S.J., Moore P.J., Smale D.A. 2017. The role of kelp species as biogenic habitat formers in coastal marine ecosystems. Ecological Responses to Environmental Change in Marine Systems, 492, 81–98.
Tegler L.A., Horner T.J., Galy V., Bent S.M., Wang Y., Kim H.H., et al. 2024. Distribution and drivers of organic carbon sedimentation along the continental margins. AGU Advances, 5(4): e2023AV001000.
Thompson P.L., Anderson S.C., Nephin J., Robb C.K., Proudfoot B., Park A.E., et al. 2023. Integrating trawl and longline surveys across British Columbia improves groundfish distribution predictions. Canadian Journal of Fisheries and Aquatic Sciences, 80(1): 195–210.
Turner J.T. 2015. Zooplankton fecal pellets, marine snow, phytodetritus and the ocean's biological pump. Progress in Oceanography, 130, 205–248.
Unsworth R.K.F., Cullen-Unsworth L.C., Jones B.L.H., Lilley R.J. 2022. The planetary role of seagrass conservation. Science, 377(6606): 609–613.
Vanderklift M.A., Herr D., Lovelock C.E., Murdiyarso D., Raw J.L., Steven A.D.L. 2022. A guide to international climate mitigation policy and finance frameworks relevant to the protection and restoration of blue carbon ecosystems. Frontiers in Marine Science, 9. Available from https://www.frontiersin.org/articles/10.3389/fmars.2022.872064.
Vaughan D. 2017. Fishing effort displacement and the consequences of implementing Marine Protected Area management—an english perspective. Marine Policy, 84, 228–234.
Verra. 2020. Methods for monitoring of carbon stock changes and greenhouse gas emissions and removals in tidal wetland restoration and conservation project activities (M-TW). Verified Carbon Standard—VCS Module VMD0051, Sectoral Scope, 14(V1):43pp.
Verra. 2021. Methodology for tidal wetland and seagrass restoration. Verified Carbon Standard—VCS Methodology VM0033, Sectoral Scope, 14(V2): 135pp.
Verra. 2023. Methodology for avoided bottom trawling—development ID M0165. Methodology Concept Note. Sectoral Scope, 14. Available from https://verra.org/methodologies/methodology-for-avoided-bottom-trawling/.
Victorero L., Watling L., Deng Palomares M.L., Nouvian C. 2018. Out of sight, but within reach: A global history of bottom-trawled deep-sea fisheries from >400 m depth. Frontiers in Marine Science, 5. Available from https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2018.00098.
Williamson P., Gattuso J.-P. 2022. Carbon removal using coastal blue Carbon ecosystems is uncertain and unreliable, with questionable climatic cost-effectiveness. Frontiers in Climate, 4. Available from https://www.frontiersin.org/articles/10.3389/fclim.2022.853666.
Zeng Y., Friess D.A., Sarira T.V., Siman K., Koh L.P. 2021. Global potential and limits of mangrove blue carbon for climate change mitigation. Current Biology, 31(8): 1737–1743.
Zhang W., Porz L., Yilmaz R., Kuhlmann J., Neumann A., Liu B., et al. 2023. Impact of bottom trawling on long-term carbon sequestration in shelf sea sediments. ESS Open Archive, pre-print.
Zhang W., Porz L., Yilmaz R., Wallmann K., Spiegel T., Neumann A., et al. 2024. Long-term carbon storage in shelf sea sediments reduced by intensive bottom trawling. Nature Geoscience.
Zhao B., Zhuang Q., Shurpali N., Köster K., Berninger F., Pumpanen J. 2021. North American boreal forests are a large carbon source due to wildfires from 1986 to 2016. Scientific Reports, 11(1): 7723.
Ziegler S.L., Baker R., Crosby S.C., Colombano D.D., Barbeau M.A., Cebrian J., et al. 2021. Geographic variation in Salt Marsh structure and function for Nekton: A guide to finding commonality across multiple scales. Estuaries and Coasts, 44(6): 1497–1507.
Supplementary material
Supplementary Material 1 (DOCX / 2.71 KB).
- Download
- 2.71 MB
Information & Authors
Information
Published In
FACETS
Volume 10 • January 2025
Pages: 1 - 14
Editor: Derek Tittensor
History
Received: 23 April 2024
Accepted: 4 November 2024
Version of record online: 17 January 2025
Notes
This paper is part of a collection titled “Climate change and the Canadian marine conservation framework”.
Copyright
© 2025 Authors Epstein, Fuller, Turner, Baum, and the Crown. This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
Data Availability Statement
All data generated from this research are publicly available at https://doi.org/10.5683/SP3/MM21UX.
Key Words
Sections
Subjects
Authors
Author Contributions
Conceptualization: GE, SDF, JKB
Data curation: GE, MT
Formal analysis: GE
Funding acquisition: SDF, JKB
Investigation: GE
Methodology: GE, SDF, SCJ, EMR, JKB
Project administration: SDF, JKB
Supervision: SDF, JKB
Validation: GE, SDF, SCJ, EMR, JKB
Visualization: GE
Writing – original draft: GE
Writing – review & editing: GE, SDF, SCJ, EMR, MT, JKB
Competing Interests
The authors declare there are no competing interests.
Funding Information
Oceans North: Mitacs-Accelerate, Fellowship
Natural Sciences and Engineering Research Council of Canada: ALLRP571068-21
Mitacs: Mitacs-Accelerate, Fellowship
This work was funded by a Natural Sciences and Engineering Research Council (NSERC) Alliance partnership grant #ALLRP571068 – 21 to JKB, and is publication No. 003 of Blue Carbon Canada. GE is also supported by a Mitacs-Accelerate Fellowship, jointly funded by Oceans North.
Metrics & Citations
Metrics
Other Metrics
Citations
Cite As
Graham Epstein, Susanna D. Fuller, Sophia C. Johannessen, Emily M. Rubidge, Melissa Turner, and Julia K. Baum. 2025. Protection of seabed sediments in Canada's marine conservation network for potential climate change mitigation co-benefit. FACETS.
10: 1-14.
https://doi.org/10.1139/facets-2024-0080
Export Citations
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.
There are no citations for this item