Zvi Steiner

My ORCID: https://orcid.org/0000-0002-9584-4956

Trace and Major Element Biogeochemistry in the Ocean

My research uses water chemistry to quantify biogeochemical processes in the ocean with a focus on major elements and the concentrations of transition metals in seawater. These include, for example, utilisation of the unique tendencies of different groups of organisms to incorporate trace constituents into their skeletons and modulate ambient seawater chemistry by this uptake as a way to quantify their abundance in the ocean, and the effect of global change on the abundance of major groups of organisms on ocean basin scales.

Another research topic is ocean boundaries. My focus is on how the sediment – bottom water interface, estuaries, hydrothermal vents, and dust dissolution effect the supply and removal of trace and major elements in the ocean, and their impact on regional ecosystems.

Current projects

1. GEOTRACES: We are studying the cycling of various trace metals in the ocean as part of the international GEOTRACES programme. In 2021-2023 we investigated the dispersion of trace metals from the Rainbow hydrothermal plume in the Atlantic mid-ocean ridge, and crossed the Pacific Ocean twice from South America to Oceania. In 2024 we will have a GEOTRACES cruise in the South Indian Ocean from Durban (South Africa) to Fremantle (Australia). These cruises are excellent opportunities to obtain high quality water chemistry data for a variety of elements, and study how different processes act together in the ocean.
2. Ocean acidification processes: To better understand climate change implications on the oceans, we are using major elements to quantify the abundance of skeleton secreting organisms and develop tools to monitor the effects of ocean acidification on skeleton secreting organisms at the ocean basin scale.
3. River-ocean interactions: Rivers are a major source of dissolved and particulate matter to the ocean but their real contribution is not always obvious from the chemical composition of river waters because processes happening when river and seawater mix may alter the solubility of various elements. We are working in different river estuaries to unravel how estuarine processes modulate the trace metal fluxes from the rivers to the open ocean, and what are the actual contributions of rivers to ocean biogeochemistry.
4. EMS-FORE: The Mediterranean Sea is one of the fastest warming marine regions on Earth. As part of a joint project with the University of Haifa, we are studying the carbon cycle of the eastern Mediterranean to determine the effect of higher temperatures on ocean biogeochemistry in a model oligotrophic subtropical gyre. We also study sediment profiles and element fluxes between the sediment and bottom-water to unravel the changes undergone by this region in the last centuries due to climate change and direct anthropogenic activity; our aim is to understand what is expected to happen in the subtropical oceans as global temperatures increase.