Kyra H. Kim

NASA · Jet Propulsion Laboratory

Dissolved inorganic carbon (DIC) and total alkalinity (AlkT) fluxes to the nearshore ocean can directly impact the rates of primary production, coral reef formation, coastal ocean acidification, and continental shelf ecology. Current understanding of the transformations that DIC and AlkT undergo as they move from land to sea are limited, leading to...

Groundwater provides nearly half of irrigation water supply, and it enables resilience during drought, but in many regions of the world, it remains poorly, if at all managed. In heavily agricultural regions like California’s Central Valley, where groundwater management is being slowly implemented over a 27-year period that began in 2015, groundwate...

Subsidence induced by groundwater depletion is a grave problem in many regions around the world, leading to a permanent loss of groundwater storage within an aquifer and even producing structural damage at the Earth’s surface. California’s Tulare Basin is no exception, experiencing about a meter of subsidence between 2015 and 2020. However, underst...

Sandy beach aquifers are complex hydrological and biogeochemical systems where fresh groundwater and seawater mix. The extent of the intertidal mixing zone and the rates of circulating flows within beaches are a primary control on porewater chemistry and microbiology of the intertidal subsurface. Interplay between the hydrological and biogeochemica...

California’s Central Valley aquifer is a critical freshwater resource for the state, providing drinking water to 6.5 million residents and irrigation water for more than half of the nation’s produce. Increasing demands have led to a steady decline of aquifer water levels, leading to irreversible compaction and land subsidence. The Sustainable Groun...

The intertidal zone of beach aquifers hosts biogeochemical transformations of terrestrially derived nutrients that are mediated by reactive organic carbon from seawater infiltration. While dissolved organic carbon is often assumed the sole reactive organic carbon component, advected and entrapped particulate organic carbon (POC) is also capable of...

Biogeochemical reactions within intertidal zones of coastal aquifers have been shown to alter the concentrations of terrestrial solutes prior to their discharge to surface waters. In organic‐poor sandy aquifers, the input of marine organic matter from infiltrating seawater supports active biogeochemical reactions within the sediments. However, whil...

Beach aquifers host a dynamic and reactive mixing zone between fresh and saline groundwater of contrasting origin and composition. Seawater, driven up the beachface by waves and tides, infiltrates into the aquifer and meets the seaward-discharging fresh groundwater, creating and maintaining a reactive intertidal circulation cell. Within the cell, l...

The intertidal zone of sandy beach aquifers hosts dynamic mixing zones between fresh groundwater and saline seawater. Wave and tidal action drive seawater up the beachface, which infiltrates into the sand and mixes with seaward-discharging fresh groundwater. This creates and sustains an intertidal circulation cell, defined by elevated salinity. The...

Accurate estimation of nutrient fluxes to estuaries and the ocean is essential for designing appropriate management strategies to protect coastal ecosystems. It is complicated, however, by challenges not only in quantifying groundwater fluxes, but also in assessing the impacts of both the origin of discharging water and biogeochemical reactions alo...