Freshwater faces a warmer and saltier future from headwaters to coasts: climate risks, saltwater intrusion, and biogeochemical chain reactions

Biogeochemistry, Год журнала: 2025, Номер 168(2)

Опубликована: Март 10, 2025

Abstract Alongside global climate change, many freshwater ecosystems are experiencing substantial shifts in the concentrations and compositions of salt ions coming from both land sea. We synthesize a risk framework for anticipating how change increasing pollution saltwater intrusion will trigger chain reactions extending headwaters to tidal waters. Salt ‘chain reactions,’ where chemical products one biogeochemical reaction influence subsequent ecosystem responses. Different impact drinking water quality, ecosystems, infrastructure, energy food production. Risk factors include salinity sources due amplification pulses interaction precipitation variability human activities. Depending on other factors, retention can range 2 90% across watersheds globally. retained interacts with cycles along flowpaths contributes ‘fast’ ‘slow’ associated temporary acidification long-term alkalinization freshwaters, impacts nutrient cycling, CO , CH 4 N O, greenhouse gases, corrosion, fouling, scaling deoxygenation, contaminant mobilization freshwater-marine continuum. also carbon cycle quantity quality organic matter transported coasts. identify double wide services. Our salinization is based analyses of: (1) temporal trends tributaries freshwaters Chesapeake Bay freshening mainstem over 40 years changes streamflow, sea level rise, watershed pollution; (2) loads major rivers Eastern U.S. increased riverine exports coastal waters sometimes 100-fold greater than forest reference conditions; (3) varying ion concentration-discharge relationships at Geological Survey (USGS) sites U.S.; (4) empirical between specific conductance Na + Cl − SO 2− Ca 2+ Mg K USGS (5) dissolved (DOC) different (6) original experiments demonstrating composition, nutrients metals, alkalinization, oxidation–reduction potentials, deoxygenation non-tidal The activities altering sources, transport, storage, reactivity entire helps anticipate, prevent, manage growing water, health, aquatic life, agriculture,

Язык: Английский

Natural and human drivers of salinity and major ion composition in United States lakes

EarthArXiv (California Digital Library), Год журнала: 2024, Номер unknown

Опубликована: Авг. 23, 2024

Salinity and major ion composition are important for understanding predicting lake water quality responses to global changes. However, little is known about salinity ionic populations of lakes at the continental scale, nor corresponding relationships with natural human factors operating multiple spatial scales. To fill these knowledge gaps, we examined patterns in using specific conductance as a proxy (N=9,785 lakes) concentrations (N=1,218 across conterminous United States. We then quantified between wide range multi-scaled both composition. Most had relatively low (median=206μS/cm), although 4% were classified saline (>1,500μS/cm) mostly located Plains, Desert Southwest, Southeast regions. Calcium bicarbonate dominant or most common ions 61% US lakes, remaining dominated by magnesium sodium sulfate chloride ions. Lake was strongly related (e.g., elevation, soil, hydrology) influenced including agriculture atmospheric deposition. Major associated similar factors, but also affected road density, urban development, agricultural activities, This macroscale their complex characteristics around needed assess, predict, manage impairments from alterations chemistry.

Язык: Английский