Effects Of Inundation Research Articles

Mangrove biomass productivity and sediment carbon storage assessment at selected sites in Mauritius: The effect of tidal inundation, forest age and mineral availability

Abstract CO2 is the most abundant anthropogenic greenhouse gas released in the environment and is considered one of the main drivers of global warming and ensuing climate change. Biological carbon sequestration mitigates CO2 through ecosystems like forests, wetlands, and agricultural lands. Mangrove forests, being highly carbon-dense ecosystems, sequester significant carbon in their biomass and soils. This study aims at evaluating the carbon storage potential of R.mucronatanatural and planted forests in Mauritius and the effect of tidal inundation and mineral availability.
Plant height and diameter at breast height were measured in situ with the GLOBE Observer application and a measuring tape, respectively. Rate of canopy coverage over the past twenty years was assessed using historical Landsat images available on Google Earth Pro. Allometric equations were used to estimate the above-ground biomass (AGB) and below-ground biomass (BGB) of R.mucronata. Total organic carbon (TOC) and all essential nutrients for plant growth were analysed using standard methods. 
Our findings show that in both natural and planted forests, the more inundated zones were first established. However, tree and sapling density and AGB were negatively correlated with sodium (r = -0.830; -0.880, respectively). Positive correlations between AGB and NO3-N, NH4-N, phosphate, and manganese suggest that these minerals were limiting factors. Nevertheless, the combination of forest age and salinity was found to play key roles on the AGB and TOC, which is linked to materials originating from the mangroves. It is noteworthy that the Ferney forest with a relatively lower salinity (5-15 ppt) and the only forest that had already reached a steady state in 2010, had a relatively much higher AGB (326.2±26.3 t ha-1) than the global average for R.mucronata (94.8 t ha-1), let alone Rhizophora spp. (281 t ha-1). The TOC registered at Ferney (47.34%) was also higher than the global values reported (2.00±2.20% to 40.00±2.20%)

Modeling the spatial distribution of Spartina alterniflora ecological response to the interaction of flooding and soil salinity base on UAV data in Coastal Wetland

ABSTRACT Spartina alterniflora Loisel poses risks to local vegetation types and coastal wetland. Managing the S. alterniflora invasion necessitates modeling its ecological response to the combined effects of flooding and soil salinity. Therefore, we integrate in situ sampling data and unmanned aerial vehicle point cloud data to quantitatively assess the effect of interaction between inundation and soil salinity on S. alterniflora and model the spatial distribution of S. alterniflora at the landscape scale. The study findings indicated that the optimal ecological amplitude for S. alterniflora in terms of flooding depth ranged from 0 to 1.02 m. Similarly, the optimal ecological amplitude for soil salinity was found to be between 9.47 and 26.13 g/kg. Based on these parameters, we were able to generate comprehensive habitat maps that depict the most suitable locations for the growth of S. alterniflora species across a larger landscape. The optimal distribution ranges for the canopy height and aboveground biomass of S. alterniflora were 1474.88 and 1307.99 ha, respectively. This research represents the first spatially quantitative investigation into the interaction effect of inundation and soil salinity on S. alterniflora. Furthermore, it provides a model for the optimal distribution range of S. alterniflora across expansive landscapes.

Combined effect of temporal inundation and aboveground-cutting on the growth performance of two emergent wetland plants, Phragmites australis and Bolboschoenus planiculmis.

Phragmites australis is a common foundation species found in inland and brackish estuarine ecosystems. P. australis stands provide a wide range of habitats for wetland organisms and perform essential functions, such as nutrient cycling, pollutant filtration, wave energy reduction, and soil stabilization. However, excessive growth of P. australis can degrade the quality of wetland habitats, thereby reducing the functions of restored wetlands. In this study, we investigated the effectiveness of vegetation management techniques, such as aboveground cutting and temporal inundation with varying depth and periodicity, in controlling the growth performance of P. australis and adjacent vegetation, Bolboschoenus planiculmis. Differences in growth responses to manipulated inundation stress between P. australis and B. planiculmis were measured. Inundation stress of 10-50 cm caused significantly greater inhibition of growth performance in B. planiculmis compared to P. australis. The combination of aboveground-cutting and inundation treatments resulted in a significant inhibitory effect on the growth performance and survival rate of P. australis. The growth performance of P. australis, including stem volume and biomass, decreased and its mortality rate increased. Our manipulated experiment suggests a combined treatment approach of moderate inundation, such as 5-10 cm for 20-30 days, and aboveground cutting to manage the overgrowth of P. australis in restored brackish wetlands.

Flood simulation using LISFLOOD and inundation effects: A case study of Typhoon In-Fa in Shanghai

Urban flooding threatens residents and their property, necessitating timely and accurate flood simulations to enhance prevention measures. However, as a megacity, Shanghai presents a complex underlying surface that proves challenging to assess accurately in existing studies. To simulate the dynamic flooding caused by Typhoon In-Fa in Shanghai from July 23rd to 28th 2021, we employed the LISFLOOD hydrodynamic model with multi-source data and validated the flooded area using the S1FLOOD deep learning model with Sentinel-1 satellite imagery. Based on simulated flood results and a flood depth classification system, we quantified the impacts of flood inundation on population, land use, and buildings. Key findings include: (1) The most severe flooding period in Shanghai occurred on July 25th and 26th 2021. (2) The LISFLOOD model effectively captured the extent of inundation, with the very-high flood depth zone covering 98.07 % of the area identified as flooded by the S1FLOOD and Sentinel-1. (3) Peak-affected individuals were recorded on July 25th 2021. (4) Farmland experienced the most extensive flooding among land use types, while residential buildings were notably affected among building types. Our study reconstructed the spatiotemporal dynamics of Typhoon In-Fa-induced flooding in Shanghai. We mapped the spatial extent and water depths, revealing the dynamic impacts of inundation on population, land use, and buildings across urban areas. This comprehensive framework for flood simulation and inundation impact analysis offers a valuable approach to improve urban flood emergency response.

Effect of brackish water inundation on temperate coastal acid sulfate soils under different vegetation types

AbstractCoastal wetland soils are frequently underlain by sulfidic materials. Sea level fluctuations can lead to oxidation of sulfidic materials in acid sulfate soils (ASS) and increased acidity which mobilises trace metals when water levels are low, and inundation of coastal wetland soils and reformation of sulfidic materials when water levels are high. We measured the effect of surface water level fluctuations in soils from coastal wetland sites under four different vegetation types: Apium gravedens (AG), Leptospermum lanigerum (LL), Phragmites australis (PA) and Paspalum distichum (PD) on an estuarine floodplain in southern Australia. We assessed effects of fluctuating water levels on reduced inorganic sulfur (RIS) in terms of acid volatile sulfide (AVS), chromium reducible sulfur (CRS) and trace metals (Fe, Al, Mn, Zn, Ni). Intact soil cores were incubated under dry, flooded and wet–dry cycle treatments of 14 days for a total of 56 days. The flooded treatment increased RIS concentrations in most depths in the AG, PA and PD sites. Lower CRS concentrations occurred in all sites in the dry treatment due to oxidation of sulfidic materials when the surface layer was exposed to lower water levels. CRS was positively correlated with SOC in all treatments. The highest net acidity occurred in the dry treatment and lowest occurred in the flooded treatment in most sites. Inundation with seawater caused SO42− reduction and decreased soluble Fe in the PA and PD sites. General decreases in Al, Zn and Ni concentrations in flooded treatments may have been due to adsorption onto colloids or co‐precipitation with slight increases in pH. SO42− concentrations decreased in the LL, PA and PD sites in the flooded treatment due to reformation of pyrite. In general, accumulation of RIS in soils under different vegetation types following brackish water inundation varied according to vegetation type, which may be linked to differences in organic material input and particle size distribution. Geochemical characteristics reflected whether oxidation or reduction processes dominated at each site in the wet–dry cycle treatments, with oxidation dominating in the LL and PA sites and reduction dominating in the AG and PD sites. This is likely due to more readily decomposable organic matter forming sulfidic materials during short periods of inundation.

Influence of surface structure and tube material on the condensation heat transfer coefficient of n-butane on horizontal single tubes and in tube bundles

The present study examines the condensation heat transfer coefficient αcond of n-butane on the outside of different horizontal tubes and in corresponding tube bundles. Experiments were conducted with a smooth tube, finned tubes with various fin densities, fin heights and tube materials, and a high-performance condensation tube (HPT) at vapor temperatures of (40 and 78) °C and varying heat flux densities q̇. The influence of inundation on αcond was systematically investigated by varying the mass flow of liquid condensate at q̇ of (20 and 60) kW·m−2. Differences between the experimental results from this work and previous ones for propane on the same condensation tubes could be explained with the help of the thermophysical properties and, thus, the retention angle of the condensate in the channels between the fins and the condensate layer thickness. For single copper tubes, αcond increased with increasing fin densities from (19 to 48) fins per inch and was between 9 and 17 times larger than for the smooth tube. This enhancement factor even reached a value of about 24 for the HPT. These increases can be attributed in part to the increased surface area, but the strongest effect appears to be related to surface tension-driven drainage of the condensate. In addition to the experimental investigations, αcond of the finned condensation tubes was predicted using an analytical model for the condensation heat transfer on finned tubes. Here, excellent agreement with an average deviation from the experimental results of 6.6 % could be found. Studies of the inundation effect have shown that the expected decrease in αcond due to the additional condensate impinging on the tubes inside bundles and increasing the film thickness often holds, but is partially counteracted by other effects and depends on the tube geometry.

Development and application of a simplified biophysical model to study deltaic and coastal ecosystems

Many coastal regions around the globe experience land loss due to high relative sea level rise rates, declining sediment supply, and a host of other anthropogenic factors. To evaluate possible restoration strategies, we developed a computationally efficient Simplified Biophysical Model (SBM). The SBM includes hydrodynamic, morphodynamic, and marsh inundation components. The hydrodynamic and mineral sediment processes of the SBM are based on open source Delft3D models. The marsh inundation MATLAB module is a simplified vegetation response to salinity and inundation used to estimate annual organic accretion rates. Organic accretion is added annually to the morphodynamic calculations of mineral sediment. The typical run time for the SBM for an area of 4500 km2 is ∼0.8, 2.5, and 4.7 days real time for one, three, and five decade simulations, respectively which is considered a computationally efficient for modeling decadal landscape evolution. The utility of the SBM was demonstrated through an application to assess the performance of a sediment diversion in the Barataria Basin in Louisiana, USA. The model results demonstrate the importance of incorporating the impact of salinity and inundation effects on the resilience of marshes subjected to high rates of relative sea level rise. Further, the sediment reduction analysis confirms the critical impact of the Mississippi River sediment decline on potential land building from sediment diversions where 1.5%, and 3% annual declining rates show a reduction in net land gain due to Mid-Barataria Sediment Diversion operation of 30% and 50 %, respectively. This highlights the importance of considering the Mississippi River sediment supply decline in restoration projects’ planning and specifically, sediment diversions.

Technogenic transformation of the Lena River floodplain near Yakutsk and assessment of landscape disturbance

The Tuymaada Valley located in the Yakutsk region represents the most developed region within the Lena River fllodplain. Landscape studies conducted here between 2016 and 2022 revealed a significant level of technogenic transformation: 30.4 % of its sites showed a high and moderate degree of disturbance. The primary driver of landscape development was the transformation of forested areas into meadows due to centuries of grazing in the floodplain. The current trend in evolution involves replacing agricultural stows with residential ones, leading to an increase in mechanical disturbances to the landscape structure. Water protection dams have removed significant areas of the left bank floodplain from the flood zone. Consequently, some of its stows become swamped, while others transform into dry wastelands with low-value steppe meadows. Currently, at the investment justification stage, the issue of providing comprehensive protection for the entire left bank of the Tuymaada valley from the adverse effects of floods and inundations is under consideration. For its continued growth, it is essential to implement not just protective measures but also environmental and improvement measures for both existing and new urban, rural, and economic-technical zones on the developing technogenic terrace.

CFD simulation of the inundation effect for saturated propane vapor condensation on the surface of a horizontal tube using the volume of fluid method

The inundation of the lower tubes in a tube bundle with condensate formed on the upper tubes is among the major causes of reduced condensation rate. Experimental methods can hardly be used to get detailed information on the inundation effect, since each factor that controls the condensation process should be considered individually. However, CFD modelling using direct interface-tracking methods is an effective tool for analyzing such processes. This paper reports the results of simulation of the saturated propane vapor condensation on the surface of a horizontal tube using the Volume of Fluid method with the modified Lee model. The study presents, for the first time, the characteristics of saturated vapor condensation including the effect of inundation predicted using a 3D model. The interphase surface and the distribution of instantaneous heat transfer coefficients over the surface of the inundated pipe are presented. It has been shown that increasing the temperature of the condensate flow can substantially affect the distribution of the heat transfer rate over the tube surface due to the formation of a thermal entrance region. These results may become a starting point for modelling condensation in a tube bundle that enjoys current interest in practice.

Whole value at risk for flood damage estimates through spatial data analysis

Effective disaster risk reduction (DRR) for flooding requires a comprehensive estimate of the whole value at risk (WVAR) to inform appropriate and proportionate mitigation expenditure. Conventional flood risk estimation methods focus on the direct effects of inundation on community value and generally ignore collateral effects on assets and populations outside the flooded area. Consequently, conventional methods tend to underestimate the cost of flooding, leading to an underestimate of the return on DRR investment. Using spatial data analysis in an urban case study for Toronto, Canada, we identify and capture the collateral value at risk (ColVaR) to estimate the WVAR more comprehensively. In our case study, ColVaR (mean estimate) amounts to 70% of direct losses (ColVar = $344 M; direct losses = $475 M CAD), ranging from 20%–150% (ColVar $100–$740 M) when spanning the 90% confidence intervals of our Monte Carlo simulations. Thus, we demonstrate that if the collateral value at risk is ignored, WVAR can be significantly underestimated, potentially leading to reduced disaster risk reduction resource allocations and thereby adding risk exposure for communities. We present an accessible, seven-step process using existing spatial analysis tools and techniques that infrastructure stakeholders and planners can use to estimate ColVaR and better formulate DRR measures for their communities.

Influence of surface structure and tube material on the condensation heat transfer coefficient of propane on horizontal single tubes and in tube bundles

The condensation heat transfer of propane on the outside of single horizontal tubes and in tube bundles was investigated by determining the condensation heat transfer coefficient αcond in a newly designed experimental setup. To study the influence of different surface structures and tube materials, experiments were conducted with a smooth tube, finned tubes with various fin densities and heights, and a high-performance condensation tube at vapor temperatures of 30 and 40 °C and varying heat flux densities. In addition, the influence of inundation on αcond was systematically investigated by varying the mass flow of liquid condensate at heat flux densities of 20 and 60 kW·m−2. The experimental setup was successfully validated using smooth tubes by a comparison of the resulting αcond with literature data and Nußelt's film theory. For the single copper tubes with fin densities from 19 to 48 fins per inch, αcond increased and was by factors of 9 to 21 larger than for the smooth tube at the same heat flux density. Investigations of the inundation effect have shown that the additional condensate can lead to an increasing condensate film thickness, which decreases αcond due to its increased thermal resistance, and/or can lead to turbulences in the condensate film, which increases αcond. The interplay of the two effects depends highly on the surface geometry. An increasing fin height always enhanced αcond, whereas a lower thermal conductivity of the tube material leads to a smaller αcond.

Microbial assemblages in Arctic coastal thermokarst lakes and lagoons.

Several studies have investigated changes in microbial community composition in thawing permafrost landscapes, but microbial assemblages in the transient ecosystems of the Arctic coastline remain poorly understood. Thermokarst lakes, abrupt permafrost thaw features, are widespread along the pan-Arctic coast and transform into thermokarst lagoons upon coastal erosion and sea-level rise. This study looks at the effect of marine water inundation (imposing a sulfate-rich, saline environment on top of former thermokarst lake sediments) on microbial community composition and the processes potentially driving microbial community assembly. In the uppermost lagoon sediment influenced from marine water inflow, the microbial structures were significantly different from those deeper in the lagoon sediment and from those of the lakes. In addition, they became more similar along depth compared with lake communities. At the same time, the diversity of core microbial consortia community decreased compared with the lake sediments. This work provides initial observational evidence that Arctic thermokarst lake to lagoon transitions do not only substantially alter microbial communities but also that this transition has a larger effect than permafrost thaw and lake formation history.

Projections of land use/cover change and habitat quality in the model area of Yellow River delta by coupling land subsidence and sea level rise

Accurately assessing future land use/cover change (LUCC) and habitat quality (HQ) is vital for ensuring sustainable use of coastal ecosystem services, but most studies ignore the effects of seawater inundation. This study developed a framework based on the PLUS model and InVEST-HQ model that considers seawater inundation due to sea level rise (SLR) and land subsidence. We used this framework to simulate future LUCC and HQ under different scenarios in the Yellow River Delta (YRD). The results showed: (1) From 1991 to 2020, natural wetlands decreased by 39.87 %, non-wetlands decreased by 3.06 %, and artificial wetlands increased by 730.71 %. The overall HQ showed a decreasing trend, with the largest decrease in non-wetlands. (2) Land subsidence occurred in 93.26 % of the YRD, with a subsidence rate of −36.55 mm/year. Underground brine mining is the most important driving factor. About 6.81 %∼11.16 % of the area will be inundated in 2035, and about 9.39 %∼19.27 % of the area will be inundated in 2050. (3) Future multi-scenario simulations show that the Ecological-Protection scenario can minimize the ecological losses caused by seawater inundation. The simulation of future HQ will be underestimated when seawater inundation is not considered. Our study shows that seawater inundation caused by land subsidence and SLR must be taken into account when simulating LUCC and HQ in coastal areas.

Demographics and risk of isolation due to sea level rise in the United States

Within coastal communities, sea level rise (SLR) will result in widespread intermittent flooding and long-term inundation. Inundation effects will be evident, but isolation that arises from the loss of accessibility to critical services due to inundation of transportation networks may be less obvious. We examine who is most at risk of isolation due to SLR, which can inform community adaptation plans and help ensure that existing social vulnerabilities are not exacerbated. Combining socio-demographic data with an isolation metric, we identify social and economic disparities in risk of isolation under different SLR scenarios (1-10 ft) for the coastal U.S. We show that Black and Hispanic populations face a disproportionate risk of isolation at intermediate levels of SLR (4 ft and greater). Further, census tracts with higher rates of renters and older adults consistently face higher risk of isolation. These insights point to significant inequity in the burdens associated with SLR.

Response of soil aggregate stability to plant diversity loss along an inundation stress gradient in a reservoir riparian zone

Dam-triggered periodic wetting and drying has increased the disintegration of soil particles in riparian areas. Most studies in this field have primarily explored the effects of vegetational characteristics on soil stability. However, the impact of plant diversity loss on the soil aggregate stability under periodic inundation stress remains unclear. This study investigated the relevant plant characteristics, root traits, and soil physicochemical properties in a typical riparian ecosystem along a hydrological stress gradient. Data-driven models were used to quantify the paths influencing soil aggregate stability through root traits under heterogeneous inundation stress. The findings showed that as inundation stress intensified, there was an overall decline in plant community diversity and soil aggregate stability in this riparian zone. Perennial herbs with fibrous root systems, as the dominant species, played an essential role in the subsurface soil aggregate stability under intense inundation stress, in contrast to the critical role of plant diversity under weak inundation stress. Moreover, the results revealed that root volume density and macroaggregate carbon content mediated the effects of plant diversity on riparian soil stability. Overall, the results suggest that suitable plants with high root volume density benefit essential soil aggregate stability under well-documented inundation effects in riparian zones.

Exploratory modelling of the impacts of sea-level rise on the Sundarbans mangrove forest, West Bengal, India

In this paper we conduct exploratory simulations of the possible evolution of the Indian Sundarbans mangroves to 2100 under a range of future sea-level rise (SLR) scenarios, considering the effects of both inundation and shoreline erosion. The Sea Level Affecting Marshes Model (SLAMM) is used to simulate habitat transitions due to inundation and these outputs are combined with an empirical model of SLR-driven shoreline erosion. A set of plausible climate-induced SLR scenarios are considered, together with delta subsidence and constrained vertical sediment accretion. Significant mangrove decline is found in all cases: the greater the rise in sea level the greater the losses. By the end of the century, the Indian Sundarbans mangroves could lose between 42 % and 80 % of their current area if current management is continued. Managed realignment could offset these losses but at the expense of productive land and the migration of the human population.

Urban rainfall-runoff flooding response for development activities in new urbanized areas based on a novel distributed coupled model

The development and construction activities of new urbanized areas lead to drastic changes in land use, resulting in severe flood disasters. The main purpose is to systematically reveal the response process to urban stormwater under different urban development degree (DD) and low-impact development (LID) implementation. A novel distributed hydrological and hydrodynamic coupled model (DHHCM), consisting of a sub-catchment-based hydrological method for plot areas and a grid-based hydrodynamic method for road areas was developed in this study. The Fengxi New Town, China was applied as the research object, a total of 11 combined events of DDs (0%, 20%, 40%, 60%, 80% and 100%) and LID deployment were simulated under five rainfall return periods (P = 2a, 5a, 30a,50a and 100a) to explore their impact on the flood process. The results indicated that the DD and the LID implementation have no obvious impact on road flood when P ≤ 5a. However, the road flood increases significantly with the increase of DD when P ≥ 30a. The peak discharge of the drainage system significantly increases with the increase in DD under different return periods, and the average peak discharge increases the most obviously (2.62 m3/s) under P = 30a. The implementation of LID measures has significantly improved the mitigation effect of surface inundation, drainage system discharge and runoff control, and its effect has increased with the DD increase. It is with great significance to accurately control the flood disaster evolution process in urban development activities, and provide data and technical support for quantifying the risks and losses in policy making.

Assessing the effectiveness of adaptation against sea level rise in Japanese coastal areas: protection or relocation?

Sea level rise (SLR) due to climate change poses a serious threat to human populations in coastal areas. As a result, assessing the impacts of SLR and evaluating potential adaptations is essential. This study assesses the impacts of SLR and ocean tides on coastal Japanese prefectures by estimating the extent of potentially inundated areas, affected populations, and economic damages. The latest climate scenarios, tidal data, and shared socioeconomic pathways (SSPs) are used to estimate the SLR and its inundation effects at a resolution of 1 km. Economic damages are estimated following the methods outlined in the “Manual for economic evaluation of flood control investment (draft).” It was found that all impacts (inundated areas, affected populations, and economic damages) under RCP2.6-SSP1 are significantly smaller than those under RCP8.5-SSP5, suggesting the importance of mitigation efforts. In addition, the study evaluates the cost and effectiveness of protection and relocation adaptations using data on the cost of constructing dikes and the cost of relocating houses and infrastructure. While relocations due to SLR have not yet been undertaken in Japan, the relocation costs could be estimated based on the conventional scheme of community relocation for natural disasters such as life-threatening floods and tsunamis caused by major earthquakes. It was found that the costs of relocation can exceed those of protection under the current framework of Japanese relocation policies.

Riparian and terrestrial grasses display unexpected tolerance to cool-season inundation

Vegetation condition has declined along many regulated river systems globally due to alteration of flow regimes via flow regulation. Understanding how plants respond to inundation is critical for managing regulated river flows to improve riparian vegetation condition. We experimentally tested the effects of inundation duration on the survival and growth of six tufted grass species commonly found in riparian zones in south-eastern Australia. We conducted three nursery-based experiments in late winter/early spring, corresponding with natural temperate flow peaks and managed flows, with inundation treatments on: (1) established plants, up to 35 days inundation; (2) seedlings, up to 25 days inundation; and (3) established plants, up to 53 days inundation including additional shaded treatments. Plant survival, height and biomass growth, and onset of flowering were recorded for established plants, and, for seedlings, survival only. Plant height and biomass growth declined with longer inundation duration across all species, although surprisingly few established plants died. Unexpectedly, grass seedlings were generally tolerant of inundation also, although there was some evidence of increased mortality for the longest treatment (25 days inundation). Shading did not result in increased mortality or reduced height growth of inundated plants. Inundation effects on the onset of flowering were modest and varied between species ranging from earlier to delayed onset. Our results suggest that tufted grasses are tolerant of cool-season inundation. Given that mortality of these species has been observed in the field and experimentally under shorter inundation periods in warmer conditions (late spring and summer), we suggest that seasonal timing of inundation is critical in determining plant responses to inundation.

Salinization, inundation and tree mortality interact to affect greenhouse gas emissions from stressed coastal forests

Sea level rise and intensifying storms cause salinization and freshwater inundation of coastal forest soils which can result in tree mortality and altered ecosystem carbon (C) cycling. However, it is not yet clear if increased salinity and inundation will affect greenhouse gas (GHG) emissions to feed back with climate change. To assess the impacts of in situ chronic and pulsed salinity on GHG fluxes from coastal forests, we made continuous measurements of carbon dioxide and methane fluxes from intact soil cores collected in 1) an upland forest dominated by loblolly pine (Pinus taeda) and a freshwater swamp dominated by baldcypress (Taxodium distichum) 2) adjacent forest stands within forest types experiencing high versus low salinization and associated tree mortality and 3) before and after pulsed salinity from a hurricane related storm surge. In lab mesocosms, all soil cores were exposed to three levels of rainwater addition to assess potential interactive effects between salinization and inundation. We found that chronic salinization and associated tree mortality decreased soil CO2 fluxes in loblolly, but not baldcypress forest with in situ soil inundation patterns potentially driving the site effect. Additionally, in an upland loblolly forest, pulsed salinity from a storm surge exhibited the potential to increase CH4 fluxes. Finally, the effect of rainwater inundation on CH4 fluxes was greater in low compared to high salinity stands suggesting that salinization may have suppressed the effects of rainwater inundation on CH4 fluxes. Overall, we show that complex interactions between biotic and abiotic conditions in stressed coastal forests can alter GHG emissions, highlighting a need for future research focused on understanding the mechanisms driving GHG fluxes from coastal forests under changing environmental conditions.