scholarly journals Enhanced decomposition offsets enhanced productivity and soil carbon accumulation in coastal wetlands responding to climate change

2011 ◽  
Vol 8 (4) ◽  
pp. 987-993 ◽  
Author(s):  
M. L. Kirwan ◽  
L. K. Blum
Keyword(s):  
Organic Matter ◽  
Soil Carbon ◽  
Sea Level Rise ◽  
Sea Level ◽  
Elevated Co2 ◽  
Coastal Wetlands ◽  
Elevated Temperatures ◽  
Carbon Accumulation ◽  
Measured Temperature ◽  
Elevated Co2 And Temperature

Abstract. Coastal wetlands are responsible for about half of all carbon burial in oceans, and their persistence as a valuable ecosystem depends largely on the ability to accumulate organic material at rates equivalent to relative sea level rise. Recent work suggests that elevated CO2 and temperature warming will increase organic matter productivity and the ability of marshes to survive sea level rise. However, we find in a series of preliminary experiments that organic decomposition rates increase by about 20% per degree of warming. Our measured temperature sensitivity is similar to studies from terrestrial systems, three times as high as the response of salt marsh productivity to temperature warming, and greater than the productivity response associated with elevated CO2 in C3 marsh plants. Although the experiments were simple and of short duration, they suggest that enhanced CO2 and warmer temperatures could actually make marshes less resilient to sea level rise, and tend to promote a release of soil carbon. Simple projections indicate that elevated temperatures will increase rates of sea level rise more than any acceleration in organic matter accumulation, suggesting the possibility of a positive feedback between climate, sea level rise, and carbon emissions in coastal environments.

scholarly journals Enhanced decomposition offsets enhanced productivity and soil carbon accumulation in coastal wetlands responding to climate change

2011 ◽  
Vol 8 (1) ◽  
pp. 707-722 ◽  
Author(s):  
M. L. Kirwan ◽  
L. K. Blum
Keyword(s):  
Organic Matter ◽  
Soil Carbon ◽  
Sea Level Rise ◽  
Sea Level ◽  
Elevated Co2 ◽  
Coastal Wetlands ◽  
Elevated Temperatures ◽  
Carbon Accumulation ◽  
Measured Temperature ◽  
Elevated Co2 And Temperature

Abstract. Coastal wetlands are responsible for about half of all carbon burial in oceans, and their persistence as a valuable ecosystem depends largely on the ability to accumulate organic material at rates equivalent to relative sea level rise. Recent work suggests that elevated CO2 and temperature warming will increase organic matter productivity and the ability of marshes to survive sea level rise. However, we find that organic decomposition rates increase by about 12% per degree of warming. Our measured temperature sensitivity is similar to studies from terrestrial systems, twice as high as the response of salt marsh productivity to temperature warming, and roughly equivalent to the productivity response associated with elevated CO2 in C3 marsh plants. Therefore, enhanced CO2 and warmer temperatures may actually make marshes less resilient to sea level rise, and tend to promote a release of soil carbon. Simple projections indicate that elevated temperatures will increase rates of sea level rise more than any acceleration in organic matter accumulation, suggesting the possibility of a positive feedback between climate, sea level rise, and carbon emissions in coastal environments.

scholarly journals The temperature sensitivity of organic matter decay in tidal marshes

2014 ◽  
Vol 11 (4) ◽  
pp. 6019-6037 ◽  
Author(s):  
M. L. Kirwan ◽  
G. R. Guntenspergen ◽  
J. A. Langley
Keyword(s):  
Organic Matter ◽  
Sea Level Rise ◽  
Sea Level ◽  
Temperature Sensitivity ◽  
Carbon Accumulation ◽  
Tidal Marshes ◽  
Moderate Increase ◽  
Elevated Atmospheric Co2 ◽  
Matter Production ◽  
Soil Elevation

Abstract. Approximately half of marine carbon sequestration takes place in coastal wetlands, including tidal marshes, where ecosystems accumulate organic matter to build soil elevation and survive sea level rise. The long-term viability of marshes, and their carbon pools, depends in part on how the balance between productivity and decay responds to climate change. Here, we report the sensitivity of soil organic matter decay in tidal marshes to seasonal and latitudinal variations in temperature measured over a 3 year period. We find a moderate increase in decay rate at warmer temperatures (3–6% °C−1, Q10 = 1.3–1.5). Despite the profound differences between microbial metabolism in wetlands and uplands, our results indicate a strong conservation of temperature sensitivity. Moreover, simple comparisons with organic matter production suggest that elevated atmospheric CO2 and warmer temperatures will accelerate carbon accumulation in marsh soils, and enhance their ability to survive sea level rise.

Coastal wetland substrate elevation is dynamically related to accommodation space and influenced by sea-level rise

2021 ◽  
Author(s):  
Kerrylee Rogers ◽  
Neil Saintilan
Keyword(s):  
Organic Matter ◽  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Surface Elevation ◽  
Elevation Change ◽  
Accommodation Space ◽  
Sediment Volume ◽  
Surface Elevation Change

<p>The resilience of coastal wetlands in the fate of sea-level rise is proposed to be related to the combined influence of changes in substrate organic matter volume, mineral sediment volume, auto-compaction of accumulating material and deep subsidence; however, relatively few studies have measured all of these variables. In addition, there is ongoing debate about the suitability of this data for modelling the behaviour of coastal wetlands under anticipated sea-level rise projections as temporal discrepancies in the elevation response of coastal wetlands derived from observational and stratigraphic records exist. To resolve these issues, data derived from a range of techniques sensitive to changes occurring at annual, decadal and century timescales, is presented in the context of available accommodation space, that is, the space in which tidally-borne material can accumulate. Focussing on an embayment in Victoria, Australia, analyses confirm that at annual-decadal timescales, organic matter behaves like a sponge, compressing as the overburden of material accumulates, resulting in auto-compaction that modulates the degree of surface elevation change that occurs as tidally-borne material accumulates. These processes operate concurrently and are influenced by sediment availability, yet vary on the basis of available accommodation space. At longer timescales, the influence of auto-compaction diminishes as organic matter has undergone significant compression and decomposition, yet accumulated material remains proportional to available accommodation space. These analyses confirm that temporal discrepancies in rates of substrate elevation change can be resolved by accounting for the timescale over which processes operate and the influence of sea-level rise on available accommodation space. Accordingly, models should dynamically consider rates of surface elevation change relative to available accommodation space.</p>

scholarly journals Temperature sensitivity of organic-matter decay in tidal marshes

2014 ◽  
Vol 11 (17) ◽  
pp. 4801-4808 ◽  
Author(s):  
M. L. Kirwan ◽  
G. R. Guntenspergen ◽  
J. A. Langley
Keyword(s):  
Organic Matter ◽  
Sea Level Rise ◽  
Sea Level ◽  
Temperature Sensitivity ◽  
Carbon Accumulation ◽  
Tidal Marshes ◽  
Moderate Increase ◽  
Elevated Atmospheric Co2 ◽  
The Face ◽  
Soil Elevation

Abstract. Approximately half of marine carbon sequestration takes place in coastal wetlands, including tidal marshes, where organic matter contributes to soil elevation and ecosystem persistence in the face of sea-level rise. The long-term viability of marshes and their carbon pools depends, in part, on how the balance between productivity and decay responds to climate change. Here, we report the sensitivity of labile soil organic-matter decay in tidal marshes to seasonal and latitudinal variations in temperature measured over a 3-year period. We find a moderate increase in decay rate at warmer temperatures (3–6% per °C, Q10 = 1.3–1.5). Despite the profound differences between microbial metabolism in wetlands and uplands, our results indicate a strong conservation of temperature sensitivity. Moreover, simple comparisons with organic-matter production suggest that elevated atmospheric CO2 and warmer temperatures will accelerate carbon accumulation in marsh soils, and potentially enhance their ability to survive sea-level rise.

scholarly journals Sedimentation and soil carbon accumulation in degraded mangrove forests of North Sumatra, Indonesia

2018 ◽  
Author(s):  
Daniel Murdiyarso ◽  
Bayu Budi Hanggara ◽  
Ali Arman Lubis
Keyword(s):  
Soil Carbon ◽  
Sea Level Rise ◽  
Sea Level ◽  
Atomic Bomb ◽  
Carbon Accumulation ◽  
Tidal Range ◽  
Mangrove Forests ◽  
Geological Formation ◽  
Soil Carbon Accumulation ◽  
Global Sea Level

AbstractMangrove ecosystems are often referred to as “land builders” because of their ability to trap sediments transported from the uplands as well as from the oceans. The sedimentation process in mangrove areas is influenced by hydro-geomorphic settings that represent the tidal range and coastal geological formation. We estimated the sedimentation rate in North Sumatran mangrove forests using the 210Pb radionuclide technique, also known as the constant rate supply method, and found that mudflats, fringes, and interior mangroves accreted 4.3 ± 0.2 mm yr−1, 5.6 ± 0.3 mm yr1, and 3.7 ± 0.2 mm yr−1, respectively. Depending on the subsurface changes, these rates could potentially keep pace with global sea level rise of 2.6−3.2 mm yr−1, except the interior mangrove they would also be able to cope with regional sea-level rise of 4.2 ± 0.4 mm yr−1. The mean soil carbon accumulation rates in the mudflats, fringes, and interior areas were 40.1 ± 6.9 g C m−2yr−1, 50.1 ± 8.8 g C m−2yr−1, and 47.7 ± 12.5 g C m−2yr−1, respectively, much lower than the published global average of 226 ± 39 g C m−2yr−1. We also found that based on the excess of radioactive elements derived from atomic bomb fallout, the sediment in the mudflat area was deposited since over 28 years ago, and is much younger than the sediment deposited in the interior and fringe areas that are 43 years 54 years old, respectively.

scholarly journals Contributions of Organic and Mineral Matter to Vertical Accretion in Tidal Wetlands across a Chesapeake Bay Subestuary

2021 ◽  
Vol 9 (7) ◽  
pp. 751
Author(s):  
Jenny R. Allen ◽  
Jeffrey C. Cornwell ◽  
Andrew H. Baldwin
Keyword(s):  
Organic Matter ◽  
Sea Level Rise ◽  
Chesapeake Bay ◽  
Sea Level ◽  
210Pb Dating ◽  
Sediment Supply ◽  
Mineral Matter ◽  
Tidal Wetlands ◽  
Vertical Accretion ◽  
Inorganic Matter

Persistence of tidal wetlands under conditions of sea level rise depends on vertical accretion of organic and inorganic matter, which vary in their relative abundance across estuarine gradients. We examined the relative contribution of organic and inorganic matter to vertical soil accretion using lead-210 (210Pb) dating of soil cores collected in tidal wetlands spanning a tidal freshwater to brackish gradient across a Chesapeake Bay subestuary. Only 8 out of the 15 subsites had accretion rates higher than relative sea level rise for the area, with the lowest rates of accretion found in oligohaline marshes in the middle of the subestuary. The mass accumulation of organic and inorganic matter was similar and related (R2 = 0.37). However, owing to its lower density, organic matter contributed 1.5–3 times more toward vertical accretion than inorganic matter. Furthermore, water/porespace associated with organic matter accounted for 82%–94% of the total vertical accretion. These findings demonstrate the key role of organic matter in the persistence of coastal wetlands with low mineral sediment supply, particularly mid-estuary oligohaline marshes.

scholarly journals Coastal wetlands can be saved from sea level rise by recreating past tidal regimes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mahmood Sadat-Noori ◽  
Caleb Rankin ◽  
Duncan Rayner ◽  
Valentin Heimhuber ◽  
Troy Gaston ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Wetlands ◽  
Environmental Crisis ◽  
Ground Vegetation ◽  
Proof Of Concept ◽  
Tidal Regime ◽  
Vegetation Sampling ◽  
Global Environmental ◽  
Intertidal Ecosystems

AbstractClimate change driven Sea Level Rise (SLR) is creating a major global environmental crisis in coastal ecosystems, however, limited practical solutions are provided to prevent or mitigate the impacts. Here, we propose a novel eco-engineering solution to protect highly valued vegetated intertidal ecosystems. The new ‘Tidal Replicate Method’ involves the creation of a synthetic tidal regime that mimics the desired hydroperiod for intertidal wetlands. This synthetic tidal regime can then be applied via automated tidal control systems, “SmartGates”, at suitable locations. As a proof of concept study, this method was applied at an intertidal wetland with the aim of restabilising saltmarsh vegetation at a location representative of SLR. Results from aerial drone surveys and on-ground vegetation sampling indicated that the Tidal Replicate Method effectively established saltmarsh onsite over a 3-year period of post-restoration, showing the method is able to protect endangered intertidal ecosystems from submersion. If applied globally, this method can protect high value coastal wetlands with similar environmental settings, including over 1,184,000 ha of Ramsar coastal wetlands. This equates to a saving of US$230 billion in ecosystem services per year. This solution can play an important role in the global effort to conserve coastal wetlands under accelerating SLR.

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