Journal of Fisheries & Livestock Production
Open Access

Blue carbon; Coastal ecosystems; Climate change; Sea level rise; Ocean warming; Carbon sequestration; Mangroves

Introduction

As global efforts to mitigate climate change intensify, the role of natural carbon sinks particularly those found in coastal and marine ecosystems has received growing attention. Known collectively as "blue carbon" ecosystems, mangroves, seagrasses, and salt marshes capture and store large amounts of carbon dioxide (CO2), often more efficiently than terrestrial forests. These ecosystems provide critical ecological services, including habitat provision, shoreline stabilization, and water quality improvement. However, climate stressors such as sea level rise and ocean warming increasingly threaten the health and functionality of blue carbon systems. Understanding how these factors influence carbon storage and sequestration dynamics is essential for devising strategies to protect and enhance these vital ecosystems in the face of climate change [1].

Brief Description

Blue carbon refers to carbon captured by the world’s oceanic and coastal ecosystems. Unlike terrestrial carbon sinks, blue carbon ecosystems sequester carbon in both plant biomass and deep anaerobic sediments, where decomposition rates are extremely low. This unique storage mechanism allows for long-term carbon retention, which can last for centuries or even millennia. Mangrove forests, seagrass meadows, and salt marshes are the primary systems associated with blue carbon. These ecosystems not only play a pivotal role in climate regulation but also serve as buffers against coastal erosion and extreme weather events. However, their capacity to function effectively as carbon sinks is compromised by the dual threats of rising sea levels and increasing ocean temperatures [2].

Discussion

1. Blue Carbon Ecosystems and Their Role in Climate Mitigation

Mangroves, seagrasses, and salt marshes are highly productive systems that store carbon in both aboveground biomass and sediment. Mangroves, for instance, can sequester up to four times more carbon than tropical rainforests per hectare. Seagrasses trap organic particles with their leaves and stabilize sediments with extensive root systems, leading to substantial carbon accumulation [3]. Salt marshes, found in temperate regions, are similarly efficient at capturing and storing atmospheric CO2. In addition to mitigating greenhouse gas emissions, these ecosystems provide ecosystem services such as habitat for marine biodiversity, nutrient cycling, and protection against storm surges. Thus, conserving and restoring blue carbon ecosystems is not only an environmental imperative but also a climate-smart strategy [4].

2. Impacts of Sea Level Rise on Blue Carbon Dynamics

Sea level rise, driven primarily by melting glaciers and thermal expansion, poses significant challenges to coastal ecosystems. The impacts on blue carbon systems include:

Mangrove Inundation: Prolonged submergence can limit oxygen availability, leading to root suffocation and dieback.

Saltwater Intrusion: Alters salinity gradients in freshwater-influenced marshes, impacting plant community composition and reducing productivity [5].

Coastal Squeeze: As sea levels rise, natural migration of habitats inland is often blocked by human infrastructure, resulting in habitat loss.

Sediment Dynamics: Changes in sediment deposition and erosion patterns can influence carbon burial rates and long-term sequestration potential.

Adaptation mechanisms like vertical accretion (building up of sediment layers) and inland migration are crucial for resilience, but their success depends on local geomorphology and human land use.

3. Ocean Warming and Its Influence on Carbon Sequestration

Rising ocean temperatures exert both direct and indirect effects on blue carbon ecosystems:

Thermal Stress: Higher temperatures can stress plant species, reduce photosynthetic efficiency, and increase mortality rates in seagrasses and mangroves.

Algal Blooms and Hypoxia: Warming can trigger algal blooms that deplete oxygen, causing die-offs of sensitive vegetation and fauna.

Accelerated Decomposition: Warmer conditions increase microbial activity, leading to faster decomposition of organic matter and release of stored carbon.

Species Distribution Shifts: Some plant and animal species may migrate to cooler waters, altering ecosystem structure and function.

Ocean warming also exacerbates the effects of ocean acidification, which can weaken plant tissues and reduce the calcification ability of associated organisms like shellfish and coralline algae [6].

4. Synergistic Effects of Climate Stressors

Sea level rise and ocean warming do not act in isolation. Their combined effects often exacerbate ecosystem degradation:

Loss of Vegetative Cover: Reduced plant biomass due to temperature stress and inundation limits carbon uptake.

Increased Greenhouse Gas Emissions: Degraded wetlands can become sources rather than sinks of CO2 and methane.

Ecosystem Fragmentation: Combined stressors lead to loss of habitat connectivity, reducing ecosystem resilience and adaptive capacity.

These synergistic effects necessitate integrated management approaches that address multiple climate threats simultaneously [7].

5. Monitoring and Modeling Blue Carbon Dynamics

To understand and predict the impacts of climate stressors, robust monitoring and modeling systems are essential:

Remote Sensing: Satellite imagery and drones provide large-scale monitoring of habitat changes.

Sediment Core Analysis: Offers insights into historical carbon accumulation rates and long-term trends.

Carbon Budget Models: Simulate future scenarios under varying climatic and management conditions.

Ecosystem Health Indicators: Metrics such as vegetation cover, biomass, and water quality help assess ecosystem functionality.

Improved data collection supports adaptive management and helps policymakers prioritize conservation investments [8].

6. Conservation and Restoration Strategies

Protecting blue carbon ecosystems from climate-induced degradation requires proactive measures:

Habitat Restoration: Replanting mangroves and restoring tidal flows in salt marshes can revive carbon sequestration functions.

Managed Retreat: Allowing space for inland migration in response to sea level rise preserves ecosystem continuity.

Policy Instruments: Legal frameworks such as coastal zone management plans and blue carbon credits incentivize protection.

Community Engagement: Local stewardship and traditional ecological knowledge enhance the effectiveness of conservation initiatives. These strategies must be tailored to regional contexts, considering ecological, social, and economic factors [9].

7. Global and Regional Implications

The degradation of blue carbon ecosystems has global implications for climate change mitigation and regional consequences for biodiversity and coastal communities. Small Island Developing States (SIDS), in particular, face disproportionate risks due to their dependence on coastal resources and limited adaptive capacity. International efforts such as the Blue Carbon Initiative and the incorporation of coastal ecosystems into Nationally Determined Contributions (NDCs) under the Paris Agreement signal progress but require greater ambition and funding. Developing countries with vast coastal areas have an opportunity to leverage blue carbon strategies as part of sustainable development goals, aligning environmental protection with poverty alleviation and disaster resilience [10].

Conclusion

Blue carbon ecosystems represent a powerful natural solution to climate change. Their ability to capture and store carbon efficiently positions them as crucial components in global mitigation strategies. However, the dual pressures of sea level rise and ocean warming threaten to undermine their capacity to function as carbon sinks. As climate stressors intensify, the urgency to protect, restore, and manage these ecosystems becomes increasingly critical. Through scientific research, policy innovation, and community engagement, it is possible to safeguard blue carbon systems for future generations. Doing so not only contributes to climate stability but also enhances coastal resilience, supports biodiversity, and sustains livelihoods. The preservation of blue carbon under climate stress is not just an environmental necessity—it is a strategic imperative in the fight against global warming.

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