Earth Sciences and geochemistry provide powerful tools to explore the processes that shape our planet. At Kiro Lab, we focus on studying the chemistry of the ocean and past environments to understand fundamental Earth system processes, such as the carbon cycle and climate dynamics. This understanding helps us to better interpret the natural variability of the Earth system and provides valuable insights into how we might respond to future climate change.
In our group, we explore the interplay between coastal and submarine environments, exploring their dynamics across diverse spatial and temporal scales. Our research aims to unravel the fundamental processes governing these environments, providing critical insights into their role in shaping our planet's past, present, and future.
Zhao J., Ratner Narovlansky Y., Fox S., Port I. & Kiro Y.
(2026)
Quaternary Science Reviews.
388,
110095.
The Levant region of the Eastern Mediterranean is projected to experience increased drought due to rising greenhouse gas emissions. Proxy-based paleoclimate reconstructions are crucial for understanding natural hydroclimate variability, which is essential for constraining future hydroclimate changes in response to a globally warmer climate. Here, we reconstruct the lake levels of the Dead Sea in the southern Levantcurrently comprising a deep north subbasin (∼300 m) and a shallow south subbasin (a few meters)using pore-fluid Mg2+ concentrations from the Dead Sea Deep Drilling Project (DSDDP) since the last deglaciation in combination with lake hypsometry. The Mg2+-deduced lake levels are ∼50100 m higher than those inferred from published onshore records for the period ∼188 ka. We evaluated uncertainties arising from the published lake-level indicators, the Mg2+ budget and the influence of basin bathymetric evolution on the applicability of the hypsometric curve. Our results show that the Mg2+ removal through authigenic mineral formation is negligible, confirming it behaves as a first order tracer of lake-water balance. Correcting for well-constrained north basin paleo-bathymetry explains only part of the discrepancy (∼1030 m). To resolve the remaining offset, we developed a dual Mg2+ inventory model, which suggests that the separate south basin was much deeper during ∼18 to 8 ka and served as an important Mg2+ reservoir. The dual inventory model incorporates plausible ranges for the subsidence rates of the north basin, Mg2+ concentrations in the Dead Sea water bodies, and south basin size, yielding a range of lake-level estimates that propagates all of these uncertainties. The corrected Mg2+-based lake levels are consistent with previous reconstructions, leading to the development of a comprehensive lake-level compilation since the last deglaciation. The new lake level curve identifies three major droughts, at ∼13.7 ka, 11.711.3 ka, and ∼8 ka, associated with weakened Mediterranean cyclones caused by the intensification of the North Atlantic latitudinal sea surface temperature gradient following meltwater release events. Based on modern rainfall and discharge records in the watershed, the total freshwater discharge during these low stands was ca. 600800 million m3/y, accounting for ∼3050% of the pre-1960s value (prior to human-induced diversion), with the average Jerusalem rainfall dropping below 300 mm/y. The findings highlight potential challenges and considerations for future water resource management in the populated southern Levant.
Levy Y., Michael H. A., Sahu S. & Kiro Y.
(2026)
Geophysical Research Letters.
53,
11,
e2026GL122.
Saline submarine groundwater discharge (SSGD) contributes to ocean chemistry through water-rock interactions as seawater circulates in coastal aquifers. Its components, driven by different mechanisms, exhibit varying residence times and degrees of chemical alteration, so constraining solute fluxes requires quantifying each component. We estimated global density-driven and tidally driven SSGD and solute fluxes using numerical modeling and geospatial data. The modeled global fluxes of density-driven circulation, nearshore tidal circulation, and tidal pumping are 23 (3-219) km3/yr, 254 (173-275) km3/yr, and 388 (179-1,032) km3/yr, respectively. Groundwater flow models often underestimate density-driven circulation because aquifer heterogeneity creates complex salinity distributions that can increase fluxes by orders of magnitude. Accounting for heterogeneity and hydraulic conductivity uncertainty, the revised estimate for density-driven circulation is 523 (181-1,705) km3/yr, comparable to the total tidal-driven SGD. This water flux delivers similar to 3 Tmol/yr Ca2+ to the ocean, a significant fraction of the global riverine calcium input.
Weber N. & Kiro Y.
(2026)
Communications Earth and Environment.
7,
446.
The coastal ocean links land and sea through rivers and submarine groundwater discharge, which contribute to the coastal carbon budget. Groundwater discharge, including fresh groundwater and recirculated seawater, remains poorly constrained globally. Here, we compile a global dataset of coastal groundwater chemistry and estimate fluxes of dissolved inorganic carbon and total alkalinity. Using conceptual reaction models, we analyze the alkalinity-carbon relationship to identify dominant processes. These patterns reflect carbonate dissolution and precipitation, and organic matter remineralization under oxic and anoxic conditions, indicating that coastal aquifers function as geochemical reactors. Recirculated seawater sampled inland is more enriched than nearshore groundwater, consistent with longer residence time and enhanced water-rock interaction. Groundwater contributes 37 percent of riverine dissolved inorganic carbon flux, equivalent to 2.72.9 and 2.2-2.4 trillion moles per year of dissolved inorganic carbon and alkalinity, depending on lithology and redox conditions. This emphasizes the importance of incorporating groundwater fluxes into Earth system models.
