Related Experiment Video
Updated: Jan 8, 2026
10:28
Investigating the Relationship between Sea Surface Chlorophyll and Major Features of the South China Sea with Satellite Information
Published on: June 13, 2020
6.3K
Salinity-driven stratification enhances riverine mercury export to the coastal ocean
Roland P Ovbiebo1, Cathryn D Sephus1, Amina T Schartup1
1Scripps Institution of Oceanography, University of California San Diego, USA.
Estuarine, Coastal and Shelf Science
|December 18, 2025
Summary
Estuarine stratification significantly increases mercury (Hg) export to coastal oceans, with potential for greater methylmercury (MeHg) production. Climate change may intensify this effect, impacting ocean Hg levels.
Area of Science:
- Environmental Chemistry
- Oceanography
- Ecosystem Dynamics
Background:
- Rivers are major pathways for mercury (Hg) transport to coastal oceans, with estuaries playing a critical role.
- Estuarine circulation and stratification significantly influence the export of metals, including Hg, but their specific impact on Hg transformation and methylation is not fully understood.
Purpose of the Study:
- To investigate the influence of estuarine stratification on mercury (Hg) transport and methylmercury (MeHg) production.
- To model Hg transformation under varying salinity-driven stratification regimes (well-mixed, slightly stratified, highly stratified).
Main Methods:
- Development of three numerical models to simulate Hg transformation.
- Utilized data from the Chesapeake Bay (CPB) and Hudson River Estuary (HRE) in the U.S.A.
- Assessed Hg export and burial under different stratification scenarios.
Main Results:
- Stratification increases riverine Hg export by 19% in CPB and 20% in HRE.
- Shorter Hg residence times under stratification promote faster export, while unstratified conditions favor Hg burial.
- Slightly stratified conditions in CPB led to an 11.5% increase in MeHg production and a 16.4% increase in MeHg export.
Conclusions:
- Estuarine stratification enhances Hg and MeHg export to coastal oceans.
- Seasonal river discharge variations influence stratification and Hg export dynamics.
- Projected increases in estuarine stratification due to climate change may lead to elevated Hg and MeHg inputs into coastal marine environments.
Related Concept Videos
02:32Osmoregulation in Fishes
52.7K
When cells are placed in a hypotonic (low-salt) fluid, they can swell and burst. Meanwhile, cells in a hypertonic solution—with a higher salt concentration—can shrivel and die. How do fish cells avoid these gruesome fates in hypotonic freshwater or hypertonic seawater environments?
52.7K
01:06Primary Production
25.0K
The total amount of energy acquired by primary producers in an ecosystem is called gross primary production (GPP). However, of this energy, producers use some for metabolic processes, and some is lost as heat, decreasing the amount of energy available to the next trophic level. The remaining usable amount of energy is called the net primary productivity (NPP). In terrestrial ecosystems, NPP is driven by climate, while light penetration and nutrient availability drive NPP in aquatic ecosystems.
25.0K
02:02Responses to Salt Stress
14.2K
Salt stress—which can be triggered by high salt concentrations in a plant’s environment—can significantly affect plant growth and crop production by influencing photosynthesis and the absorption of water and nutrients.
14.2K
01:27Diversity of Protists III
706
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...
706