Variable Impacts of Climate Change on Blue Carbon

One Earth, Journal Year: 2020, Volume and Issue: 3(2), P. 195 - 211

Published: Aug. 1, 2020

Summary

Blue carbon provides opportunities to mitigate climate change while increasing ecosystem services for coastal communities, including adaptation; however, blue ecosystems are vulnerable change, leading uncertainties in the future efficacy of these ecosystems. In this review, we assess potential impacts on carbon. Despite uncertainties, sequestration is enhanced by landward migration habitats, maintenance sediment supply, restoration, and improved water quality. As an example, mangroves could result 1.5 Pg 2100. Mudflats, seaweed beds, swamp forests also contribute mitigation, although there large data gaps. Achieving full requires protection restoration facilitation changes distributions with actions that will deliver adaptation benefits. Conversely, worst-case squeeze scenario, losses 3.4 sequestered 2100 occur.

Language: Английский

---

Storage, patterns and influencing factors for soil organic carbon in coastal wetlands of China

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(20), P. 6065 - 6085

Published: June 30, 2022

Soil organic carbon (SOC) in coastal wetlands, also known as "blue C," is an essential component of the global C cycles. To gain a detailed insight into blue storage and controlling factors, we studied 142 sites across ca. 5000 km covering temperate, subtropical, tropical climates China. The wetlands represented six vegetation types (Phragmites australis, mixed P. australis Suaeda, single Spartina alterniflora, mangrove [Kandelia obovata Avicennia marina], tidal flat) three invaded by S. alterniflora (P. K. obovata, A. marina). Our results revealed large spatial heterogeneity SOC density top 1-m ranging 40-200 Mg ha-1 , with higher values mid-latitude regions (25-30° N) compared those both low- (20°N) high-latitude (38-40°N) regions. Vegetation type influenced density, having largest followed mangrove, Suaeda flat. increased 6.25 following invasion community but decreased 28.56 8.17 marina communities. Based on field measurements published literature, calculated total inventory 57 × 106 soil China's wetlands. Edaphic variables controlled content, chemical properties explaining variance content. Climate did not control content had strong interactive effect edaphic variables. Plant biomass quality traits were minor contributor regulating highlighting importance quantity OC inputs balance between production degradation within These findings provide new insights stabilization mechanisms sequestration capacity

Language: Английский

---

Deconstructing the mangrove carbon cycle: Gains, transformation, and losses

Ecosphere, Journal Year: 2024, Volume and Issue: 15(3)

Published: March 1, 2024

Abstract Mangroves are one of the most carbon‐dense forests on Earth and have been highlighted as key ecosystems for climate change mitigation adaptation. Hundreds studies investigated how mangroves fix, transform, store, export carbon. Here, we review synthesize previously known emerging carbon pathways in mangroves, including gains (woody biomass accumulation, deadwood soil sequestration, root litterfall production), transformations (food web transfer through herbivory, decomposition), losses (respiration CO 2 CH 4 , export, particulate dissolved export). We then technologies available to measure fluxes their potential, limitations. also compare mangrove net ecosystem productivity (NEP) with terrestrial forests. Finally, update global estimates current values area. found that contributions recently fluxes, such respiration minor (<1 Tg C year −1 ), while lateral significant (>35 ). Dissolved inorganic exports an order magnitude higher than other processes were highly variable, highlighting need further studies. Gross primary (GPP) (ER) per area within same However, ER/GPP was lower explaining sequestration. estimate mean NEP 109.1 (7.4 Mg ha ) or a budget balance, accounting losses, 66.6 (4.5 Overall, productive, despite due tidal exchange, they sinks.

Language: Английский

---

Climate and plant controls on soil organic matter in coastal wetlands

Global Change Biology, Journal Year: 2018, Volume and Issue: 24(11), P. 5361 - 5379

Published: June 29, 2018

Coastal wetlands are among the most productive and carbon-rich ecosystems on Earth. Long-term carbon storage in coastal occurs primarily belowground as soil organic matter (SOM). In addition to serving a sink, SOM influences wetland ecosystem structure, function, stability. To anticipate mitigate effects of climate change, there is need advance understanding environmental controls SOM. Here, we investigated influence four formation factors: climate, biota, parent materials, topography. Along northern Gulf Mexico, collected plant data across elevation zonation gradients within 10 estuaries that span broad temperature precipitation gradients. Our results highlight importance climate-plant indicate scale location dependent. plants sensitive change; small changes or can transform communities. Across region, was greatest mangrove forests salt marshes dominated by graminoid plants. lower flats lacked vascular succulent We quantified strong relationships between precipitation, salinity, productivity, Low leads high which limits productivity appears constrain accumulation. analyses use from but our be related globe provide foundation for predicting ecological future reductions freshwater availability. many services dependent highly vulnerable change. Collectively, regulated cascading availability could impact stability affect supply some services.

Language: Английский

---

Long‐term organic carbon sequestration in tidal marsh sediments is dominated by old‐aged allochthonous inputs in a macrotidal estuary

Global Change Biology, Journal Year: 2018, Volume and Issue: 24(6), P. 2498 - 2512

Published: Feb. 12, 2018

Abstract Tidal marshes are vegetated coastal ecosystems that often considered as hotspots of atmospheric CO 2 sequestration. Although large amounts organic carbon ( OC ) indeed being deposited on tidal marshes, there is no direct link between high deposition rates and sequestration due to two main reasons. First, the may become rapidly decomposed once it buried and, second, a significant part preserved be allochthonous has been sequestered elsewhere. In this study we aimed identify mechanisms controlling long‐term in marsh sediments along an estuarine salinity gradient (Scheldt estuary, Belgium Netherlands). Analyses have shown during inundations up millennia old. This component effectively these sediments, indicated by low radiocarbon content . Furthermore, fractionation showed autochthonous decadal timescale saltmarsh while freshwater locally produced biomass more efficiently after burial. Our results show decoupled from local production studied sediments. implies greatly overestimated when they calculated based short‐term rates, which controlled labile inputs. Moreover, not in‐situ, does contribute active ecosystems. A correct assessment contribution total sedimentary stock well understanding fate both necessary avoid overestimations rate in‐situ

Language: Английский

---

Fingerprinting Blue Carbon: Rationale and Tools to Determine the Source of Organic Carbon in Marine Depositional Environments

Frontiers in Marine Science, Journal Year: 2019, Volume and Issue: 6

Published: May 22, 2019

Blue carbon is the organic in oceanic and coastal ecosystems that captured on centennial to millennial timescales. Maintaining increasing blue an integral component of strategies mitigate global warming. Marine vegetated (especially seagrass meadows, mangrove forests, tidal marshes) are hotspots their degradation loss worldwide have reduced stocks increased CO2 emissions. Carbon markets, conservation restoration schemes aimed at enhancing sequestration avoiding greenhouse gas emissions, will be aided by knowing provenance fate carbon. We review critique current methods potential nascent track carbon, including: bulk isotopes, compound-specific biomarkers, molecular properties, environmental DNA. find most studies date used isotopes determine provenance, but this approach often cannot distinguish contribution different primary producers depositional marine environments. Based our assessment, we recommend application multiple complementary methods. In particular, use nitrogen lipids along with DNA a great identify source quantify sedimentary ecosystems. Despite promising these new techniques, further research needed validate them. This critical overview can inform future help underpin methodologies for implementation focused climate change mitigation schemes.

Language: Английский

---

Linear and nonlinear effects of temperature and precipitation on ecosystem properties in tidal saline wetlands

Ecosphere, Journal Year: 2017, Volume and Issue: 8(10)

Published: Oct. 1, 2017

Abstract Climate greatly influences the structure and functioning of tidal saline wetland ecosystems. However, there is a need to better quantify effects climatic drivers on ecosystem properties, particularly near climate‐sensitive ecological transition zones. Here, we used climate‐ literature‐derived data from wetlands test hypotheses regarding influence (i.e., temperature precipitation regimes) following six properties: canopy height, biomass, productivity, decomposition, soil carbon density, accumulation. Our analyses elucidate linear nonlinear drivers. We quantified positive relationships between above‐ground productivity strong (sigmoidal) (1) biomass height (2) height. Near temperature‐controlled mangrove range limits, small changes in are expected trigger comparatively large as forests grow, expand, and, some cases, replace salt marshes. within these same zones, temperature‐induced be small. Interestingly, despite significant across tropical–temperate mangrove–marsh zone, density or accumulation were not significant. literature review identifies several properties many regions world for which insufficient fully evaluate drivers, identified gaps can by scientists guide future research. indicate that precipitation‐controlled scant other properties. There more decomposition gradients, advance understanding freshwater availability, additional needed arid climates. Collectively, our results help managers anticipate consequences climate change coastal wetlands.

Language: Английский

---

Stocks and losses of soil organic carbon from Chinese vegetated coastal habitats

Global Change Biology, Journal Year: 2020, Volume and Issue: 27(1), P. 202 - 214

Published: Sept. 25, 2020

Abstract Global vegetated coastal habitats (VCHs) represent a large sink for organic carbon (OC) stored within their soils. The regional patterns and causes of spatial variation, however, remain uncertain. sparsity bias studies on soil OC stocks from Chinese VCHs have limited the reliable estimation capacity as global sinks. Here, we use field published data 262 sampled cores 181 surface soils to report estimates stocks, burial rates losses in China. We find that mangrove, salt marsh seagrass relatively low storing 6.3 ± 0.6, 7.5 1.6 0.6 Tg C (±95% confidence interval) top meter profile with 44 17, 159 57, 6 45 Gg C/year, respectively. variability is linked biogeographic factors but mostly impacted by sedimentary processes anthropic activities. All experienced significant losses, resulting estimated emissions 94.2–395.4 CO 2 e (carbon dioxide equivalent) over past 70 years. Reversing this trend through conservation restoration measures has, therefore, great potential contributing mitigation climate change while providing additional benefits. This assessment, national scale highly environments under intensive anthropogenic pressures, provides important insights into blue mechanism sequestration capacities, thus synchronous progression management.

Language: Английский

---

Rapid peat development beneath created, maturing mangrove forests: ecosystem changes across a 25‐yr chronosequence

Ecological Applications, Journal Year: 2020, Volume and Issue: 30(4)

Published: Jan. 29, 2020

Mangrove forests are among the world's most productive and carbon-rich ecosystems. Despite growing understanding of factors controlling mangrove forest soil carbon stocks, there is a need to advance speed peat development beneath maturing forests, especially in created restored that intended compensate for ecosystem functions lost during conversion other land uses. To better quantify rate organic matter created, we measured changes across 25-yr chronosequence. We compared properties adjacent natural forests. also quantified site-specific occurred between 2010 2016. Soil accumulated rapidly as sandy soils transitioned organic-rich (peat). Within 25 yr, 20-cm deep layer developed. The time required reach equivalency with was estimated (1) <15 yr herbaceous juvenile vegetation, (2) ~55 adult trees, (3) ~25 upper (0-10 cm), (4) ~45-80 lower (10-30 cm). For elevation change, were equivalent or surpassed within first 5 yr. A comparison chronosequence studies from ecosystems indicates accumulation may be fastest globally. In peatland ecosystems, formation occurs slowly (over centuries, millennia); however, these results show can occur decades. Peat development, primarily due subsurface root accumulation, enables sequester carbon, adjust their relative sea level, adapt changing conditions at dynamic land-ocean interface. face climate change rising levels, coastal managers increasingly concerned longevity functionality restoration efforts. Our pace which improve predictions responses global restoration.

Language: Английский

---

Blue carbon benefits from global saltmarsh restoration

Global Change Biology, Journal Year: 2023, Volume and Issue: 29(23), P. 6517 - 6545

Published: Sept. 25, 2023

Coastal saltmarshes are found globally, yet 25%-50% reduced compared with their historical cover. Restoration is incentivised by the promise that marshes efficient storers of 'blue' carbon, although claim lacks substantiation across global contexts. We synthesised data from 431 studies to quantify benefits saltmarsh restoration carbon accumulation and greenhouse gas uptake. The results showed store approximately 1.41-2.44 Pg carbon. Restored had very low (GHG) fluxes rapid accumulation, resulting in a mean net rate 64.70 t CO2 e ha-1 year-1 . Using this estimate potential rates, we find regeneration could result 12.93-207.03 Mt per year, offsetting equivalent up 0.51% energy-related emissions-a substantial amount, considering represent <1% Earth's surface. Carbon rates GHG varied contextually temperature, rainfall dominant vegetation, eastern coasts USA Australia particular hotspots for storage. While study reveals paucity some variables continents, suggesting need further research, offset emissions clear. ability facilitate natural now rests principally on action management-policy community financial opportunities supporting restoration.

Language: Английский

---