Salt Marsh Ecosystems Research Articles

Leveraging a decade of Landsat-8 spectral records for mapping blue carbon storage in tidal salt marshes

Tidal salt marsh ecosystems are known to accumulate and store large amounts of “blue” carbon, making them an important component of regional carbon cycle processes and a potential target for ecosystem-based carbon crediting efforts. However, blue carbon content in salt marshes can vary substantially at relatively small spatial scales. Understanding spatial variations of blue carbon storage at the landscape or local scale is important for developing carbon inventories, guiding ecological restorations, and informing habitat management strategies. We investigated the potential of spectral index records from the Landsat-8 Operational Land Imager spanning from 2014 to 2023 for mapping blue carbon storage in the soils of two tidal salt marsh systems in the Mid-Atlantic United States. The decadal mean of a non-photosynthetic vegetation index and standard deviations of a normalized difference vegetation index and a modified normalized difference water index were identified as predictors of blue carbon. These predictors were used to train a gradient boosted trees model for predicting soil organic matter content that achieved a testing set r-squared value of 0.67. We estimated that the two study marshes stored a combined 133–208 Gg of organic carbon in the top 30 cm of soil. We emphasize the need for better quantification of deep soil carbon in tidal salt marsh systems, which is likely quite high, and demonstrate the potential for satellite-based mapping of blue carbon within individual tidal wetland systems.

Blue carbon dynamics across a salt marsh-seagrass ecotone in a cool-temperate estuary

Abstract Background Seagrass and salt marsh ecosystems are recognised for their role in climate change mitigation and adaptation given their carbon storage potential. However, factors driving variability in blue carbon ecosystems are understudied, yet are important to account for. Aims Examine the variability of sediment organic carbon (SOC) and its drivers (seagrass morphometrics and sediment nutrients) at different spatial scales; > 1 km, ~ 150 m and ~ 10 m across the salt marsh-seagrass ecotone. Methods We collected the top 5 cm of sediment in the Olifants River Estuary, a cool-temperate system in South Africa. Using a line transect approach, we sampled across the salt marsh-seagrass ecotone (~ 10 m) in triplicate transects (~ 50 m apart) at three sampling sites (1–3 km) and analysed for SOC and elemental nutrient (nitrogen and phosphorus) content. Seagrass morphometrics (shoot density, leaf length and number per shoot) were measured. Results There was significant (P < 0.05) spatial heterogeneity in SOC stocks between sites (1–3 km) and between salt marshes and seagrass, but low variability at ~150 m. We detected a significant decrease in SOC from salt marsh towards the seagrass edge, with seagrass SOC remaining uniform. Nitrogen content was positively correlated with SOC in seagrass and salt marshes (P < 0.05), but seagrass morphometrics were not significant drivers of SOC. Conclusions The dynamics of blue carbon differ between salt marshes and seagrass, with spatial heterogeneity of SOC at scales > 1 km, suggesting that future BC assessments need to account for spatial heterogeneity to improve the accuracy of carbon removal estimates.

Precipitation changes alter plant dominant species and functional groups by changing soil salinity in a coastal salt marsh

Specific mechanisms of precipitation change due to global climate variability on plant communities in coastal salt marsh ecosystems remain unknown. Hence, a field manipulative precipitation experiment was established in 2014 and 5 years of field surveys of vegetation from 2017 to 2021 to explore the effects of precipitation changes on plant community composition. The results showed that changes in plant community composition were driven by dominant species, and that the dominance of key species changed significantly with precipitation gradient and time, and that these changes ultimately altered plant community traits (i.e., community density, height, and species richness). Community height increased but community density decreased with more precipitation averaged five years. Furthermore, changes in precipitation altered dominant species composition and functional groups mainly by influencing soil salinity. Salinity stress caused by decreased precipitation shifted species composition from a dominance of taller perennials and grasses to dwarf annuals and forbs, while the species richness decreased. Conversely, soil desalination caused by increased precipitation increased species richness, especially increasing in the dominance of grasses and perennials. Specifically, Apocynaceae became dominance from rare while Amaranthaceae decreased in response to increased precipitation, but Poaceae was always in a position of dominance. Meanwhile, the dominance of grasses and perennials has the cumulative effect of years and their proportion increased under the increased 60% of ambient precipitation throughout the years. However, the annual forb Suaeda glauca was gradually losing its dominance or even becoming extinct over years. Our study highlights that the differences in plant salinity tolerance are key to the effects of precipitation changes on plant communities in coastal salt marsh. These findings aim to provide a theoretical basis for predicting vegetation dynamics and developing ecological management strategies to adapt to future precipitation changes.

Seasonal Temperature Distributions and Variations in Salt Marshes: Field Investigation and Numerical Simulation

AbstractSoil temperature regulates biogeochemical processes and is a key environmental factor affecting salt marsh ecosystems. Previous studies on soil temperature and heat transport in intertidal marshes predominantly focused on short‐term changes, leaving seasonal variations unclear. This study conducted a yearlong field and modeling investigation to examine temporal and spatial temperature variations in a creek‐marsh section under estuarine and meteorological influences. The results showed that inundating tidal water propagated the seasonal water temperature signal to marsh soils, especially at low elevations, thereby modulating air temperature‐induced soil temperature variations and distributions. The response of soil temperature to air and tidal water temperatures exhibited a damped and delayed pattern. In contrast, tide‐induced porewater circulations near the creek facilitated the temperature responses. A regression model incorporating a Gamma distribution function was developed to quantify the delayed and cumulative thermal effects of tidal water and air on shallow soil temperatures. The model coefficients varied along the creek‐marsh section, capturing the seasonal regulation of periodic tidal inundation on soil temperature in the low‐elevation marsh and near the creek. Sensitivity analyses indicated that relative sea level rise lowered yearly‐averaged temperatures for the marsh platform by enhancing latent heat export. Surface water warming increased the marsh temperatures at lower elevations. This study demonstrates that the creek‐marsh topography, warming, and relative sea level rise jointly affect soil temperature dynamics, advancing our understanding of temperature‐dependent biogeochemical processes in marsh ecosystems.

PREVALENCE OF THE BOPYRID ISOPOD PROBOPYRUS PANDALICOLA IN DAGGERBLADE GRASS SHRIMP FROM SALT MARSH CREEKS AND PANNES OF CAPE COD, MASSACHUSETTS.

In salt marsh ecosystems, daggerblade grass shrimp, Palaemon (Palaemonetes) pugio, play a crucial role in food webs and serve as the definitive host for the bopyrid isopod Probopyrus pandalicola. These ectoparasites infest the branchial chambers of grass shrimp, which can lead to decreased energy availability and sterilization of infected hosts. Although bopyrid isopod infestation of daggerblade grass shrimp has been frequently reported in literature from coastal marshes of the southeastern United States, the prevalence of this parasite has not been recently documented in daggerblade grass shrimp from marshes of the northeastern United States. The goal of this project was to quantify the prevalence of Pr. pandalicola infestations in Pa. pugio across Cape Cod, Massachusetts. We evaluated bopyrid isopod prevalence from shrimp collected from 5 different salt marsh habitats along Cape Cod in August 2021. Bopyrid isopod infestations were found in shrimp at 4 of 5 salt marshes, with prevalence ranging from 0.04 to 14.1%. Seasonal resampling of one of the salt marshes revealed the highest average infestation prevalence in spring (<17.1%) and an isolated high of 30.3% prevalence in a single salt panne. A series of linear and multivariate models showed that panne area, shrimp abundance, and distance to shoreline were related to Pr. pandalicola shrimp infestations in salt pannes in summer. This study describes the prevalence of the bopyrid isopod infesting daggerblade grass shrimp in salt marshes in New England, with implications for how parasitized shrimp influence salt marsh food webs in which they are found.

Environmental Sensitivity of Soil Microbial Communities is Altered in Association with Plant Roots in Saltmarsh Ecosystems

Environmental Sensitivity of Soil Microbial Communities is Altered in Association with Plant Roots in Saltmarsh Ecosystems

Tracking annual dynamics of carbon storage of salt marsh plants in the Yellow River Delta national nature reserve of china based on sentinel-2 imagery during 2017–2022

Coastal salt marshes play a key role in coastal carbon sequestration. Understanding the spatial distribution and annual changes of carbon storage of salt marsh plants at a local scale is helpful for accurate protection and restoration. However, the annual carbon storage of salt marsh plants has not yet been obtained in the Yellow River Delta National Nature Reserve (YRDNNR), China. Here, we developed a fast and reliable method to produce an annual map of carbon storage of herbaceous salt marsh plants from 2017 to 2022 based on multi-year in situ data and 10-meter resolution Sentinel-2 images in YRDNNR. That is, a deep belief network based on conjugate gradient (CGDBN) pixel-level classification, a generative adversarial network with a constrained factor (GAN-CF) measured sample expansion and multiple linear regression (MLR) quantitative inversion algorithm is used. The results showed that: (1) The carbon storage of herbaceous salt marsh plants in the YRDNNR increased in 2017–2018 and 2019–2021, with an average carbon storage dynamic of 4.53–8.39 Mg/ha. (2) In 2021, the area of salt marsh vegetation increased significantly by 20 % compared to 2017. Although its area decreased sharply due to the removal of invasive species (S. alterniflora) in 2022, the carbon storage per unit area of salt marsh plants remained at 7.77 Mg/ha. (3) The carbon storage of salt marsh vegetation showed a gradient change along the community succession from land to sea. Estimating annual carbon storage of salt marsh plants could provide basic data for recognizing the ‘blue carbon’ contribution of coastal plants and managing the coastal salt marsh ecosystem in Yellow River Delta.

Anthropogenic nitrogen pollution impacts saltmarsh resilience with inhibition of seedling establishment and population dispersal

Saltmarsh, a prominent buffer ecosystem, has been identified as an important sink for nitrogen (N) pollutants from marine- and land-based anthropogenic activities. However, how the enriched anthropogenic N impacts saltmarsh sustainability has been neglected due to limited understanding of marsh resilience based on seedling establishment and population dispersal under anthropogenic N inputs. This study combined mesocosm experiments and model simulations to quantify the effects of increased anthropogenic N on the seedling-based vegetation expansion of Spartina alterniflora. The results indicated that seedling survivals, growth rates, and morphological indicators were inhibited by 20.08 %, 37.14 %, and > 35.56 %, respectively, under 1.5 gN/kg anthropogenic N. The sensitivity rate of vegetation expansion was increased by 70 % with 1 gN/kg increased N concentration under the scenario of low seedling density (< 15 m/yr). These findings revealed an important unidentified weakness of the marsh development process to anthropogenic N inputs. Finally, we highlighted the importance of appropriate protection measures to control nutrient pollution in salt marshes. Our study provides new insights for enhancing the resilience and sustainability of saltmarsh ecosystems.

Above- and belowground plant mercury dynamics in a salt marsh estuary in Massachusetts, USA

Abstract. Estuaries are a conduit of mercury (Hg) from watersheds to the coastal ocean, and salt marshes play an important role in coastal Hg cycling. Hg cycling in upland terrestrial ecosystems has been well studied, but processes in densely vegetated salt marsh ecosystems are poorly characterized. We investigated Hg dynamics in vegetation and soils in the Plum Island Sound estuary in Massachusetts, USA, and specifically assessed the role of marsh vegetation for Hg deposition and turnover. Monthly quantitative harvesting of aboveground biomass showed strong linear seasonal increases in Hg associated with plants, with a 4-fold increase in Hg concentration and an 8-fold increase in standing Hg mass from June (3.9 ± 0.2 µg kg−1 and 0.7 ± 0.4 µg m−2, respectively) to November (16.2 ± 2.0 µg kg−1 and 5.7 ± 2.1 µg m−2, respectively). Hg did not increase further in aboveground biomass after plant senescence, indicating physiological controls of vegetation Hg uptake in salt marsh plants. Hg concentrations in live roots and live rhizomes were 11 and 2 times higher than concentrations in live aboveground biomass, respectively. Furthermore, live belowground biomass Hg pools (Hg in roots and rhizomes, 108.1 ± 83.4 µg m−2) were more than 10 times larger than peak standing aboveground Hg pools (9.0 ± 3.3 µg m−2). A ternary mixing model of measured stable Hg isotopes suggests that Hg sources in marsh aboveground tissues originate from about equal contributions of root uptake (∼ 35 %), precipitation uptake (∼ 33 %), and atmospheric gaseous elemental mercury (GEM) uptake (∼ 32 %). These results suggest a more important role of Hg transport from belowground (i.e., roots) to aboveground tissues in salt marsh vegetation than upland vegetation, where GEM uptake is generally the dominant Hg source. Roots and soils showed similar isotopic signatures, suggesting that belowground tissue Hg mostly derived from soil uptake. Annual root turnover results in large internal Hg recycling between soils and plants, estimated at 58.6 µg m−2 yr−1. An initial mass balance of Hg indicates that the salt marsh presently serves as a small net Hg sink for environmental Hg of 5.2 µg m−2 yr−1.

Tolerance of the Australian halophyte, beaded samphire, Sarcocornia quinqueflora, to Pb and Zn under glasshouse conditions: Evaluating metal uptake and partitioning, photosynthetic performance, biomass, and growth

Saltmarsh sediments are susceptible to accumulation of excessive concentrations of anthropogenically elevated metals such as lead (Pb) and zinc (Zn). The resident salt tolerant plants of saltmarsh ecosystems form the basal underpinning of these ecosystems. As such, metal-associated adverse impacts on their physiology can have detrimental flow-on effects at individual, population, and community levels. The present study assessed the accumulation and partitioning of ecologically relevant concentrations of Pb, Zn, and their combination in a dominant Australian saltmarsh species, Sarcocornia quinqueflora. Plants were hydroponically maintained under glasshouse conditions for 16 weeks exposure to either Pb (20 µg l–1), Zn (100 µg l–1), or their mixture. We evaluated the chronic toxicological effects of single and mixed metal treatments with reference to metal uptake and partitioning, photosynthetic performance, photosynthetic pigment concentration, biomass and growth. Lead was more toxic than Zn, and Zn appeared to have an antagonistic effect on the toxicological effects of Pb in S.quinqueflora in terms of metal uptake, photosynthetic performance, photosynthetic pigment concentrations, and growth. Indeed, the tolerance index was 55 % in plants treated with Pb compared to 77 % in Zn treated plants and 73 % in Pb+Zn treated plants. Finally, Sarcocornia quinqueflora primarily accumulated both Pb and Zn in roots at concentrations exceeding unity whilst translocation of these metals to above ground tissues was restricted regardless of treatment. This suggests that S. quinqueflora may be suitable for phytostabilisation of Zn, and of Pb particularly in the presence of Zn.

Functional characterisation of a new halotolerant seawater active glycoside hydrolase family 6 cellobiohydrolase from a salt marsh

Realising a fully circular bioeconomy requires the valorisation of lignocellulosic biomass. Cellulose is the most attractive component of lignocellulose but depolymerisation is inefficient, expensive and resource intensive requiring substantial volumes of potable water. Seawater is an attractive prospective replacement, however seawater tolerant enzymes are required for the development of seawater-based biorefineries. Here, we report a halophilic cellobiohydrolase SMECel6A, identified and isolated from a salt marsh meta-exo-proteome dataset with high sequence divergence to previously characterised cellobiohydrolases. SMECel6A contains a glycoside hydrolase family 6 (GH6) domain and a carbohydrate binding module family 2 (CBM2) domain. Characterisation of recombinant SMECel6A revealed SMECel6A to be active upon crystalline and amorphous cellulose. Mono- and oligosaccharide product profiles revealed cellobiose as the major hydrolysis product confirming SMECel6A as a cellobiohydrolase. We show SMECel6A to be halophilic with optimal activity achieved in 0.5X seawater displaying 80.6 ± 6.93% activity in 1 × seawater. Structural predictions revealed similarity to a characterised halophilic cellobiohydrolase despite sharing only 57% sequence identity. Sequential thermocycling revealed SMECel6A had the ability to partially reversibly denature exclusively in seawater retaining significant activity. Our study confirms that salt marsh ecosystems harbour enzymes with attractive traits with biotechnological potential for implementation in ionic solution based bioprocessing systems.

Invasion mechanism of Spartina alterniflora by regulating soil sulfur and iron cycling and microbial composition in the Jiuduansha Wetland.

Spartina alterniflora, an invasive plant widely distributed in China's coastal regions, has had a significant impact on the stability of wetland ecosystems and elemental biogeochemical cycles. The invasion of S. alterniflora has been found to lead to the accumulation of sulfides in the soil. The cycling of sulfur and iron in the soil is closely interconnected. Coastal estuarine wetlands are influenced by both freshwater in rivers and seawater tides, as well as the frequent variations in redox conditions caused by tidal fluctuations, which makes the cycling of sulfur and iron in the soil invaded by S. alterniflora more intricate. In this study, field surveys and laboratory experiments were conducted to explore the effects of S. alterniflora invasion and hydrological changes on the cycling of sulfur and iron as well as related functional microorganisms in the soil. The invasion of S. alterniflora showed an increase in soil reduced inorganic sulfur (RIS) components in both high and low marshes of Jiuduansha wetland, with higher content observed in summer and autumn. The tidal simulation experiments revealed abundant sulfate in seawater tidal conditions could promote the formation of acid volatile sulfides (AVS) in the soil of low marshes invaded by S. alterniflora and ensuring the continuous increase in AVS content. Diffusive gradients in-thin-films (DGT) technology indicated the existence of high-concentration soluble S2- enrichment zones in the soil of low marshes invaded by S. alterniflora, which may be related to S. alterniflora root exudates. Tidal action increased the relative abundance of sulfur-reducing bacteria (SRB) in the soil of low marshes, and under the influence of seawater tidal action, SRB exhibited higher relative abundance. However, S. alterniflora might inhibit the activity of iron-reducing bacteria (FeRB) in the soil of low marshes. In conclusion, S. alterniflora may enhance the sulfate reduction rate and promote the formation of free sulfides in tidal salt marsh ecosystems by releasing root exudates that stimulate the activity of SRB, while concurrently inhibiting the activity of FeRB and reducing their competition with SRB. This effect is particularly pronounced in low marshes under seawater tidal conditions. Thus, S. alterniflora is capable of rapidly invading tidal salt marshes by utilizing sulfides effectively.

Using Remote Sensing to Assess the Vegetation Cover of a Protected Salt Marsh Subjected to Artificial Recharge and Groundwater Abstractions during the Period 1925–2022 (Alicante, SE Spain)

The Agua Amarga salt marsh has been subjected to artificial seawater recharge on its surface during the period 1925–1969 for industrial purposes (saltwork activity) and from 2008 to present to compensate for coastal groundwater abstraction to supply Alicante desalination plants. This groundwater abstraction has caused piezometric depletion in the coastal aquifer connected to the protected salt marsh. The seawater recharge program also involved vegetation monitoring to control the impact on the salt marsh ecosystem, allowing data to be collected about the halophyte vegetation species growing in the salt marsh (Arthrocnemum macrostachyum, Sarcocornia fruticosa, and Ruppia maritima, among others) from spring and autumn field surveys. In this work, vegetation development is assessed with remote sensing for the period 1929–2022 using images with visible and near-infrared spectral resolution. Different spectral indices (NDVI, BI, and NDWI) and classification algorithms (random forest) are used to calculate the vegetation cover. Field data are employed to evaluate the protocols and compare the results, showing a 46% decrease caused by the salt works and a 50% increase as a result of natural evolution and artificial recharge. The spread of Phragmites australis is also addressed by comparing LiDAR data with field monitoring, showing an increase of 12% during the period 2005–2023. The advantages and complementarity of field monitoring and remote sensing information are explained.

The Physiological and Biochemical Response of Ribbed Mussels to Rising Temperatures: Benefits of Salt Marsh Cordgrass.

Salt marsh ecosystems are heavily reliant on ribbed mussel (Geukensia demissa) populations to aid in rapid recovery from droughts. The focus of this study was thus to document the effects of rising temperatures on ribbed mussel populations in a Georgia salt marsh. Seven lab and eight field experiments were used to assess the effects of current air temperatures on mussels at two high marsh (HM) sites with short and sparse cordgrass and one mid marsh (MM) site with tall and dense cordgrass. Field results in 2018 and 2019 indicate that ribbed mussels were experiencing extremely high temperatures for prolonged periods of time at the landlocked high marsh (LHM) site. In 2018, the highest temperature (54°C) and longest high temperature events, HTEs (58 days), that is, consecutive days with temperatures≥40°C, were recorded at this site. When laboratory temperatures were increased from 20 to 36°C, mean heart rates increased by an average of 19 bpm for mussels from both high and MM sites respectively. When field temperatures rose from 20°C in April to 40°C in September 2019, mean heart rates increased by an average of 10 bpm for HM mussels and by 26.3 bpm for MM mussels. Under identical laboratory and field conditions, mean heart rates for mussels from the LHM site with the highest temperatures, increased by<1 bpm and 3.7 bpm respectively. Evidence of the potential role of shade on mussel aggregates was provided by examining whether mussels from the edge of mussel aggregates with little to no cordgrass for shade were more stressed than those living at the center of mussel aggregates. In the absence of shade, mean body temperatures for mussels at the edge of mussel aggregates were up to 8°C higher than for those living in the center underneath a dense tuft of cordgrass. Despite high body temperatures, mean heart rates and Hsp70 gene expression were lower for mussels living at the edges. This agrees with the strategy that during prolong exposure to high temperatures, mussels may reduce their heart rate to conserve energy and enhance survival. Alternatively, heat-stressed mussels at the edges of aggregates may not have the resources to express high levels of Hsp70. Increase in the frequency, intensity, and duration of HTEs may stress the physiological and biochemical function of mussel populations to the limit, dictate mussel aggregate size, and threaten the functionality of SE salt marshes.

Nitrogen fertilization enhances organic carbon accumulation in topsoil mainly by improving photosynthetic C assimilation in a salt marsh

Continuous nitrogen (N) loading alters plant growth and subsequently has the potential to impact soil organic carbon (SOC) accumulation in salt marshes. However, the knowledge gap of photosynthesized carbon (C) allocation in plant-soil-microbial systems hampers the quantification of C fluxes and the clarification of the mechanisms controlling the C budget under N loading in salt marsh ecosystems. To address this, we conducted an N fertilization field observation combined with a 5 h 13C-pulse labeling experiment in a salt marsh dominated by Suaeda. salsa (S. salsa) in the Yellow River Delta (YRD), China. N fertilization increased net 13C assimilation of S. Salsa by 277.97%, which was primarily allocated to aboveground biomass and SOC. However, N fertilization had little effect on 13C allocation to belowground biomass. Correlation analysis showed that 13C incorporation in soil was significantly and linearly correlated with 13C incorporation in shoots rather than in roots both in a 0 N (0 g N m−2 yr−1) and +N (20 g N m−2 yr−1) group. The results suggested that SOC increase under N fertilization was mainly due to an increased C assimilation rate and more efficient downward transfer of photosynthesized C. In addition, N fertilization strongly improved the 13C amounts in the chloroform-labile SOC component by 295.26%. However, the absolute increment of newly fix 13C mainly existed in the form of residual SOC, which had more tendency for burial in the soil. Thus, N fertilization enhanced SOC accumulation although C loss increased via belowground respiration. These results have important implications for predicting the carbon budget under further human-induced N loading.

Individual survival is dictated by group personality in a marsh ecosystem predator–prey interaction

Abstract Predator–prey interactions structure ecological communities, and personality can significantly mediate these interactions. Personality expression is often contingent on social context, suggesting that group personality may be key in determining the outcomes of predator encounters. Here, we test the influence of individual personality and group composition on survival of the marsh periwinkle, Littoraria irrorata, when exposed to its main predator, the blue crab, Callinectes sapidus, both integral players in mediating the productivity and health of salt marsh ecosystems. Snails were categorized as having bold or shy personality types, which were unrelated to shell length, though neither trait influenced survival when individual snails were exposed to a predator. However, when snails were partitioned into groups differing in personality composition, snails in groups with bold individuals had higher survival than those in groups with none. While group type did not influence the survival of bold snails, shy snails performed better in mixed groups: the presence of a few bold individuals emerged as especially effective in decreasing mortality of shy snails. The effect of personality on predator escape is thus conditional on group personality composition, indicating that social context can directly impact the survival and success of its individual members, with broad implications for community dynamics.

Carbon Dioxide Fluxes and Influencing Factors in the Momoge Salt Marsh Ecosystem, Jilin Province, China

This study observed the characteristics and influencing factors of the carbon fluxes of the Momoge salt marsh ecosystem over four years, which behaves as a CO2 sink. The daily, seasonal, and interannual variations in CO2 fluxes in the Momoge salt marshes were observed using the eddy covariance method and were compared with various environmental factors. An overall daily “U”-shaped distribution was observed, with uptake during the day (negative values) and release at night (positive values). Annually, the carbon fluxes in the study area roughly exhibited a “V” shape. The carbon fluxes during the non-growing season predominantly showed positive values, indicating the release of CO2 into the atmosphere. Photosynthetically active radiation was the primary influencing factor affecting the hourly and daytime variations in net ecosystem exchange (NEE) during the growing season, while temperature was the main factor influencing nighttime NEE dynamics. The air temperature, soil temperature, photosynthetically active radiation, precipitation, and water level all had significant impacts on the daily net CO2 exchange. At the monthly scale, larger values of soil temperature, air temperature, photosynthetically active radiation, and aboveground biomass corresponded to a stronger carbon absorption capacity of the ecosystem. Overall, temperature remains the primary factor for carbon fluxes in the Momoge wetlands.

Assessing the Potential Impacts of Climate Change on Current Coastal Ecosystems—A Canadian Case Study

Understanding how climate change affects coastal ecosystems is one of the most important elements in determining vulnerability and resilience for long-term ecosystem management in the face of the increasing risk of coastal hazards (e.g., sea level rise, coastal flooding, and storm surge). This research attempts to undertake a study on the ecosystem–climate nexus in the Canadian province of Prince Edward Island (PEI). Cloud-based remote sensing techniques with Google Earth Engine (GGE) are utilized to identify ecosystem changes over time. In addition, the effects of coastal flooding and storm surge ecosystems under different climate scenarios are examined. The results suggest a reduction in the forest (3%), open water or marsh component (9%), salt water (5%), no open water or marsh component (3%), and salt or brackish marsh (17%) ecosystems from 2013 to 2022. Dune and beach exhibit a non-uniform distribution across the period because of variations in natural processes, with an upward trend ranging from 0% to 11%. Approximately 257 km2 (9.4%) of PEI’s ecosystems would be affected by extreme coastal flooding (scenario 4), compared to 142 km2 (5.2%), 155 km2 (5.7%), and 191 km2 (7%) in scenarios 1, 2, and 3, respectively. Under a 4 m storm surge scenario, around 223 km2 (8.2%) of PEI’s ecosystems would be flooded, compared to 61 km2 (2.2%), 113 km2 (4.1%), and 168 km2 (6.1%) under 1 m, 2 m, and 3 m scenarios, respectively. The findings from this research would enable policymakers to take necessary actions to sustain ecosystem services in PEI while confronting the impacts of climate change.

Braving the extremes: foraminifera document changes in climate-induced and anthropogenic stress in Wadden Sea salt marshes

Tidal wetlands are highly dynamic ecosystems that are susceptible to changes in sea level and flooding from storm surges. Among them, salt marshes play a key role in coastal protection as they contribute to wave attenuation through their regulating ecosystem services, thereby promoting sediment deposition and shoreline stabilization. However, the resilience of salt marshes, particularly those that have been modified and cultivated for centuries, is questionable in the face of accelerated sea-level rise (SLR) and increasing run-up heights of storm surges. In this context, this study aims to investigate the historical foraminiferal records of two sedimentary salt marsh archives from the Wadden Sea area (Dithmarschen and North Frisia, Germany) that have been modified to varying degrees by human management activities over the last century. The foraminiferal records document how physico-chemical traits of salt marshes of the central Wadden Sea have responded to storm tide inundation over the last century, providing information about salt marsh stability and vulnerability. Abnormally grown tests of the salt marsh indicator speciesEntzia macrescensincreased in number between 1950 CE and the late 1980s, indicating the concurrent increase of environmental stress caused by the effects of times of increased salt marsh flooding. These trends can be linked to observations of amplified North Sea storm surges, corroborating that salt marsh ecosystems respond to changing climate conditions. Differences in the number of abnormal foraminifera between the studied salt marshes suggest a particularly high vulnerability of intensively human-modified coastal wetland ecosystems to amplified storm climate conditions.

Expansion of Magallana Gigas Colonization: Northernmost and Southernmost Invasion on Saltmarsh Ecosystems in the SW Atlantic

Expansion of Magallana Gigas Colonization: Northernmost and Southernmost Invasion on Saltmarsh Ecosystems in the SW Atlantic