Academic Profile

The main theme in my research is the interaction between seawater and seafloor or coastal aquifers. This includes the study of water and methane discharge from the ocean floor ('cold seeps') with implications to global warming (e.g. Solomon et al. EPSL, 2008), as well as submarine Groundwater Discharge to the sea (SGD, e.g. Weinstein et al., JGR, 2007), lakes (Kinneret, Dead Sea, e.g. Kiro et al., GCA, 2012, 2013) and coastal estuaries (e.g. Shalem et al., J. Hydrology, submitted).

During my earlier works, the focus was on submarine hydrology, using instruments I developed in Scripps during my postdoc period (e.g. Kastner et al., 2000; Solomon et al., 2008). Then, the focus of research shifted to the use of natural radio-tracers, which included the establishment of a radioactive isotope lab that focuses on radium and radon research (as well as other related radionuclides, such as thorium and actinium). The advantage of using radium is that while all its four natural isotopes are radioactive, their half life (~decay rate) varies between a few days and 1,600 years, which allows their application to track processes with different time scales. We use these radionuclides to trace processes in the aquifer, fluxes of water and solutes from land to the sea and mixing between coastal water and the open sea. This includes the development of the radium groundwater dating methodology and the determination of seawater circulation time and rates in the aquifer (e.g. Kiro et al. 2013), which we hope will gain recognition as a major groundwater dating method. In 2010, we held in Jerusalem the 3rd Ra-Rn international meeting, where people both exchanged ideas and methodologies and went for a field trip at the Dead Sea to study its unique (very rich) radium and radon composition.

Another noteworthy research I am involved in is the radium balance of the whole Mediterranean (together with J. Garcia-Orellana from Barcelona), which is conducted in order to assess the general basin-scale flux of groundwater to the sea. An abstract about the preliminary results of this study was recently presented at the CIESM meeting  (Rodellas et al. 2013; Abstr. no 74, above), and a paper to Nature Geoscience is in an advanced stage of writing.

Tracing and understanding groundwater discharge patterns are important in the determination of the contribution of groundwater discharge to coastal water quality, as well as to the elemental balance of trace elements in the ocean (e.g. Fe, Mn, U, Sr isotopes and others, e.g. Kiro et al., GCA, 2013). In a paper published in the journal Environmental Science and Technology (Weinstein et al. 2011), I examined the contribution of the different SGD components to the coastal water quality at Dor Bay (northern Israel), with global implications to SGD sites. As a follow-up to this, I recently started studying two related topics. The first is the associated microbial communities in the sub-terrain (pore water), where SGD occurs, which is studied in collaboration with Prof. I. Berman-Frank from the Faculty of Life Science in BIU (the M.Sc. research of Ben Brinberg). The other is the study of seawater circulation rates in the coastal seafloor. The latter has major implications to the potential interaction of the circulated seawater with the coastal sediments and to the conveyance of solutes and contaminants to the sea. Preliminary results were presented at the last Geochemical Society Goldschmidt Meeting in Florence (August 2013; Abstract no. 72, above).

The above studies were conducted in collaboration with researchers, both from Israel (Geological Survey, Israel Oceanographic and Limnological Research and the Hebrew University) and from other countries (US, France, Spain, IAEA, Germany). We also have a large project with Palestinian researchers from the West Bank and Gaza (field work is in Gaza), which focuses on a better understanding of seawater intrusion to aquifers and groundwater discharge to the sea. It is funded by USAID MERC and coordinated by Bar-Ilan University.

Aside from the low-temperature studies, I am also engaged in 'hot' research, which is about volcanism and magma genesis in the earth's mantle. In the last few years, we published two papers that deal with accurate age determination (the Ar-Ar and OSL methods) of a sequence of volcanic events in Mt. Avital and Birket Ram from the northern Golan (Shaanan et al., JVGR, 2011; Weinstein et al., Bull. Volcanol., 2013). The paper about Mt. Avital describes a unique mechanism, where fluvio-morphological changes at the surface (damming and shifting of a river by a lava flow) caused a major shift in the style of volcanic activity, from the moderately explosive Strombolian eruption to the very aggressive style of phreatomagmatic activity. Other works deal with the tectono-magmatic association, both at mantle depth (magma generation, Regenbauer-Lieb et al., Abstract no. 76, above) and en route to the surface (Weinstein, J. Geodynamics, 2012).

Main Research Interests