Biogeochemistry

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Chemical Oceanography

Dr. Zvi Steiner
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Our group studies how interactions between the ocean and its boundaries facilitate the chemical composition of the ocean, and uses variability in seawater chemistry to quantify the function of the ocean as a carbon pump.

The ocean’s capacity to mitigate climate change is dependent on biological and geochemical processes. We seek to improve our understanding and ability to quantify variability in seawater chemistry to better assess the marine carbon cycle. We use water chemistry analyses on samples we collect from cruises in different ocean basins to quantify biogeochemical processes, focusing on major elements (calcium, strontium, lithium) and the concentrations of transition metals in seawater as indicators. As different groups of organisms tend to incorporate constituents into their skeletons in characteristic ratios, we are able to quantify their abundance in the ocean from the variability in seawater concentrations of the main elements they use for building their skeletons, and thus assess the impact of climate change on these organisms.

Ocean boundaries (e.g. sediment, river, hydrothermal vents, dust) impact the supply and removal of various elements in the ocean. Along these boundaries, we use sediment analyses to identify and quantify the mechanisms that control the formation of authigenic minerals as feedback mechanisms that restrain changes in the chemical composition of the ocean.

 

 

Contact Information

zvika.steiner@mail.huji.ac.il

 

 

 

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Carbonate System Geochemistry Lab

Prof. Jonathan Erez

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  1. Biomineralization in foraminifera and corals: Physiology, cellular mechanisms and their implications for paleoceanographic interpretations.
  2. Marine aspects of the global carbon cycle, particularly photosynthesis and calcification in corals and foraminifera in view of ocean acidification.
  3. Biogeochemistry of stable carbon isotopes in marine and aquatic systems.
  4. Development of new tools for paleoceanography and paleolimnology using stable isotopes and trace elements.
  5. Carbon and nutrient cycling in coral reefs in view of global change.

 

Research Students 

Adam Levi (PhD Student)

Sharon Ram (PhD Student)

Contact Information

Jonathan Erez | jonathan.erez@mail.huji.ac.il | 972-2-65-84882

 

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Sedimentary Oceanography

Prpf. Adi Torfstein

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Our research focuses on the signal transfer between the modern atmosphere and oceans to the geological record, the impact of abrupt events on primary and export production in the oceans, trace element cycles, and reconstruction of Quaternary paleoclimate from lacustrine and marine archives. We combine between time series of modern marine and terrigenous particulate fluxes, coeval seawater compositions, and biogeochemical cycles in the oceans (see the REDMAST project).

Research Students

Dr. Clara Flintrop - postdoc

Gil Lapid - Ph.D. Student

Noy Levy - Ph.D. Student (Supervised jointly with Dr. Ralf Schiebel from Max Planck Institute for Chemistry, Mainz, Germany)

Efraim Brill - M.Sc. Student

Aden Clarfield - M.Sc. Student

Lea Sivan - M.Sc. Student

Contact Information

Adi Torfstein | adi.torf@mail.huji.ac.il

Lab Manager - Sigalit Amiran-Kan

 

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Marine Biogeochemistry

Prof. Yeala Shaked

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As a marine biogeochemist, my interest revolves around the interactions between organisms and their environment, with emphasis on trace metal bioavailability to phytoplankton and redox transformations. I am intrigued by the fact that microorganisms, striving to acquire nutrients and protect themselves from external stressors, actively modify their chemical milieu and in turn influence the biogeochemical cycles of trace and major elements in the ocean. I study fundamental processes and mechanisms by combining field and laboratory measurements and experiments.

Ongoing and future projects:

  • Dust as a source of iron to Trichodesmium, a globally significant phytoplankton
  • Bioavailability of iron to phytoplankton

 

 

Research Students 

Dr. Coco Koedooder (Post-doc) 

Dr.  Futing Zhang (Post-doc) 

Anna-Neva Visser (Post-doc) 

Siyuan Wang (PhD Student)

Contact Details 

Yeala Shaked | yeala.shaked@mail.huji.ac.il

 

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Organic Geochemistry Lab

Prof. Alon Amrani 

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Organic geochemistry and biogeochemistry, stable isotopes, sulfur cycle, organic-inorganic interactions

 

Research Students 

PhD Ilya Kutuzov (Post-doc)  

Yafit Schnell Ben-Avraham (PhD Student)

Hadar Cohen Saadon (PhD Student)

Chen Davidson (PhD Student)

Sutapa Patra (PhD Student)

Vasileia Chatzi (MSc Student)

Michal Krasna (MSc Student)

Noam Mizrahi (MSc Student)

 

Contact Details

Alon Amrani |  alon.amrani@mail.huji.ac.il | Room 204 North | 972-2-65-85477

 

 

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Biosphere Climate Interactions

Biosphere-Climate Interactions

Prof. Alon Angert
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Climate Change affects the terrestrial biosphere, while changes in the biosphere feedback and affect the climate system. Understanding these complex interactions is important at these times of Global Change.
Related research in our lab tracks carbon sequestration in soils and wetlands. We measure soil carbon and not only the CO2 emitted during organic carbon decomposition but also make high-accuracy measurements of O2 influx. The comparison between these two gases enables better understanding of soil processes.

Previous research projects focus on developing the use of oxygen stable isotopes of phosphate for tracking phosphorus in dust and its biogeochemical cycling in soil. This research is based on field work, remote-sensing and lab work. These approaches could help evaluate the effects of changing climate on the terrestrial phosphorus cycle, which is an important limiting factor for plant growth.

In the last series of projects, we have developed, in collaboration with Prof. Amrani from my institute, an approach to measuring the sulfur isotopes of carbonyl sulfide (COS) and used this to determine its isotopic composition in the atmosphere, plant uptake, and seawater. This is done by sampling in the ocean and forests, and by lab experiments. Our continued research in this field will help to better constrain global-scale photosynthesis and the influence of this gas on Earth's albedo and, hence, climate.

 

 

Research students

Guy Sapir (Master) in collaboration with Yoav Rosenberg and Rotem Golan

Michal Karsana (Master) in collaboration with Prof. Alon Amrani

Chen Davidson (PhD) in collaboration with Prof. Alon Amrani

Contact Us

Prof. Alon Angert:

Room 217 south | 02-6584758 | alon.angert@mail.huji.ac.il

Tal Vainer (Lab manager): 

lab.angert@gmail.com

 

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