Impacts of typhoon-induced heavy rainfalls and resultant freshwater runoff on the partitioning of organic carbon oxidation and nutrient dynamics in the intertidal sediments of the Han River estuary, Yellow Sea

Post-disaster damage and loss assessment in the Iranian healthcare sector: a qualitative interview study

BACKGROUND

Accurate post-disaster damage and loss assessment is critical for the success of subsequent recovery programs. A comprehensive and systematic damage and loss assessment process involves evaluating the physical damage and financial impact of an event on individuals, communities, and assets. To ensure effective recovery, the various components and entities included in the program must be developed appropriately and efficiently. This study aimed to identify the components and entities of the Iranian healthcare sector's post-disaster damage and loss assessment program.

METHODS

A qualitative study employing purposive sampling and semi-structured individual interviews was conducted with 18 participants between October 2022 and July 2023, with continuing until data saturation was achieved. Data collection involved semi-structured interviews and observational notes with experts, including representatives from the National Disaster Management Organization (NDMO), the Iranian Red Crescent Society, and the Disaster Risk Management Department of the Ministry of Health and Medical Sciences Universities. The interviews were conducted in the workplace of the participants. Thematic analysis, a conventional qualitative method, was employed for the analysis of the data. Following the transcription of the recorded interviews, the initial codes were extracted, reviewed for accuracy, and classified.

RESULTS

The results of this study are based on the insights and experiences of a diverse group of qualified experts in their respective fields. The findings were analysed and classification into ten main themes, 29 sub-themes, and 1,058 codes. The main themes were key concepts and principles of assessment; assessment stages; health system measures in assessment; roles and responsibilities; team composition; information and communication; coordination and collaboration; data collection and analysis; assessment tools and methods; and reporting, documentation, and recommendations.

CONCLUSION

An understanding of key concepts and principles enables stakeholders to respond effectively to disasters, make informed decisions, and facilitate recovery and reconstruction efforts.

Spatial-temporal impacts of invasive Spartina anglica on the rates and pathways of organic carbon mineralization and resulting C-Fe-S cycles in the intertidal wetland of the Han River Estuary, Yellow Sea

To elucidate the spatial-temporal impact of invasive saltmarsh plant Spartina anglica on the biogeochemical processes in coastal wetlands, we investigated the rates and partitioning of organic carbon (Corg) mineralization in three representative benthic habitats: (1) vegetated sediments inhabited by invasive S. anglica (SA); vegetated sediments by indigenous Suaeda japonica; and (3) unvegetated mud flats. Microbial metabolic rates were greatly stimulated at the SA site during the active growing seasons of Spartina, indicating that a substantial amount of organic substrates was supplied from the high below-ground biomass of Spartina. At the SA site, sulfate reduction dominated the Corg mineralization pathways during the plant growing season, whereas iron reduction dominated during the non-growing season. Overall, due to its greater biomass and longer growing season than native Suaeda, the expansion of invasive Spartina is likely to greatly alter the Corg-Fe-S cycles and carbon storage capacity in the coastal wetlands.

Impacts of the invasive Spartina anglica on C-S-Hg cycles and Hg(II) methylating microbial communities revealed by hgcA gene analysis in intertidal sediment of the Han River estuary, Yellow Sea

We investigated the impact of invasive vegetation on mercury cycles, and identified microorganisms directly related to Hg(II) methylation using hgcA gene in vegetated mud flats (VMF) inhabited by native Suaeda japonica (SJ) and invasive Spartina anglica (SA), and unvegetated mud flats (UMF) in Ganghwa intertidal sediments. Sulfate reduction rate (SRR) and rate constants of Hg(II) methylation (K_m) and methyl-Hg demethylation (K_d) were consistently greater in VMF than in UMF, specifically 1.5, 2 and 11.7 times higher, respectively, for SA. Both K_m and K_d were significantly correlated with SRR and the abundance of sulfate-reducing bacteria. These results indicate that the rhizosphere of invasive SA provides a hotspot for Hg dynamics coupled with sulfate reduction. HgcA gene analysis revealed that Hg(II)-methylators were dominated by Deltaproteobacteria, Chloroflexi and Euryarchaeota, comprising 37.9%, 35.8%, and 6.5% of total hgcA gene sequences, respectively, which implies that coastal sediments harbor diverse Hg(II)-methylating microorganisms that previously underrepresented.

Impacts of Hurricanes on Nutrient Export and Ecosystem Metabolism in a Blackwater River Estuary Complex

Hurricanes have the ability to export uncharacteristically large amounts of nutrients from terrestrial systems into riverine and estuarine networks, altering rates of ecosystem metabolism throughout the aquatic continuum. In order to explore these impacts and compare these values to common precipitation events, water quality and chemistry data from the National Estuarine Research Reserve’s System Wide Monitoring Program (NERR-SWMP) were combined with discharge data from the United States Geological Survey (USGS) to calculate biogeochemical export from a Florida coastal blackwater river. This analysis was focused on the years 2016–2020, when Hurricanes Matthew, Irma, and Dorian impacted the landscape of Florida’s Atlantic coast. Hurricane Irma, the only hurricane to occur after especially wet summer conditions, dwarfed the other two hurricanes in the export of dissolved organic carbon (DOC), with an increase from <5 kg DOC day−1 to approximately 250 kg DOC day−1. Soluble reactive phosphorus (SRP) and most nitrogen species export exhibited similar trends. Additionally, other spikes in export occurred during non-hurricane months, and no significant differences between monthly export values were found between hurricane and non-hurricane months. However, net ecosystem metabolism (NEM) was calculated at similar intervals and revealed significantly lower NEM during months of hurricane passage. On monthly timescales, this work suggests that lower-category hurricanes might not significantly impact organic matter export, but the shortened export interval associated with hurricane impacts produces significant implications for NEM.

Human disturbance on phosphorus sources, processes and riverine export in a subtropical watershed

Phosphorus (P) is a key nutrient in freshwater systems, often acting as the limiting nutrient. The dominant sources of P in the Jiulong River watershed (S.E. China) are anthropogenic. Dissolved and particulate P species were measured in the West (WJR) and North (NJR) rivers during the wet and dry seasons of 2018 and at their river outlets during a storm (June 2019). Sources of P pollution were characterized from mainly single source subcatchments (dry season). The Agriculture source (WJR) had a total P of 114.7 ± 13.1 μg P L^-1, which was mainly dissolved inorganic P (DIP) from excess fertilizer washed from the fields. By contrast, the West Urban source (sewage effluent) was mainly particulate (POP) and dissolved organic P (DOP). The effect of reservoirs in the main NJR was to decrease total particulate P (TPP) and DIP and increase POP, due to increased sedimentation of particles and biological uptake. An increase in all P species was observed at the beginning of the storm, followed by a decrease on the rising hydrograph due to dilution. The final concentration of all P species was higher than baseflow, confirming that storms increase the P flux out of the watershed. P was initially washed off the fields during the storm, and during the falling hydrograph P increased due to interflow and other longer-term sources. The high DIN:DIP ratio confirmed the key importance of P inputs from human activities in substantially altering P sources and cycling, and hence the importance of science-based management to alleviate the eutrophication problem.

Typhoon Merbok induced upwelling impact on material transport in the coastal northern South China Sea

Typhoons frequently affect the South China Sea (SCS), playing an important role in changing the coastal marine system. To determine which process has the greatest impact on material transport in the coastal marine area during a typhoon, the sea temperature, salinity, concentration of nutrients, chlorophyll-a, total suspended matter, and δ¹³C of particulate organic carbon (δ¹³C-POC) in the water column of coastal Northern SCS (NSCS) were measured during two cruises in June 2017, in the pre- and post-typhoon Merbok periods. The results show that all parameters changed significantly between the two periods. During the pre-typhoon period, stratification of nutrients and physicochemical parameters, combined to high nutrient concentrations, high temperature, and low salinity in the water column of the nearshore area, suggests that the nearshore area is influenced by the river diluted water originated in the coastal cities adjacent to our study area. In the offshore area, mineralization may be responsible for the high nutrient concentration in the bottom water. However, during the post-typhoon, the stratification of nutrients is less significant and their distribution more homogenous in the whole water column of the nearshore area. In the upper water, the nutrient concentration increased and the temperature decreased significantly. These results suggest that the enhanced vertical mixing induced by the typhoon was the dominant process in changing the nutrient distribution pattern in the coastal NSCS.