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Joel Kronfeld

Publications and source records attributed to Joel Kronfeld.

4 recordsLinked to original sources

The effect of 20th century industrialization: Power station, acid rains, over-pumping, on an erstwhile uniform freshwater dune aquifer in Haifa Bay, Israel

A small phreatic sand dune aquifer lies along the shore of Haifa Bay. It has been exploited for its freshwater resources since the 1930s. During this time the salinity has increased continuously, partly by seawater intrusion due to overpumping. The chemistry of the young aquifer water is laterally variable and is characterized by excess SO$_4^{2-}$, high $Sr^{2+}$ concentrations above that of modern seawater, high alkalinity, and markedly enriched $δ^{13}C_{DIC}$ values. Acidic winter rains, formed from $SO_x$ and $NO_x$ gaseous emissions from a nearby power station, leach the dry deposition that accumulated across the dune surface during the dry summers. The acidity also partially dissolves the aragonite sea shells in the dune sands, remnants of a previous marine transgression. As a consequence, this adds $Sr^{2+}$, $Ca^{2+}$ excess, and alkalinity, while leading to enriched $δ^{13}C_{DIC}$ values, particularly during the winter, at which time the radiocarbon activity in the DIC is observed to decrease.

physics.geo-ph

Disentangling the soil and atmospheric stress on carbon sequestration in a Mediterranean pine forest

Sequestration of atmospheric CO$_2$ in a Mediterranean semi-arid Aleppo Pine Forest (Pinus halepensis) close to the border of the semi-arid timberline was characterized and quantified under field conditions. Measurements of organic and inorganic CO$_2$ sequestration with gas exchange and stock counting approaches were made in both rainfed control (approximately 12$\%$ average annual soil moisture) and summer irrigated plots (approximately 24$\%$ annual average soil moisture), providing the opportunity to separate the effects of atmospheric water demand from soil water stress on the atmospheric CO$_2$ sequestration responses. Measurements yield an organic carbon sequestration (OCS) rate of approximately 550 g CO$_2$ m$^{-2}$ yr$^{-1}$, two-thirds in soil and one-third in biomass. In addition, measurements yield an inorganic carbon sequestration (ICS) rate of approximately 216 g CO$_2$ m$^{-2}$ yr$^{-1}$; via calcite (CaCO$_3$) precipitation in the soil due to root exhalation of CO$_2$ (60$\%$) and microbial activity (40$\%$). The drip irrigated plot showed approximately 3 times higher organic CO$_2$ sequestration than the control plot. The organic sequestration is divided equally between the soil and the biomass. For the irrigated plot, the inorganic CO$_2$ was approximately 1.8 times higher than that of the control plot. However, for inorganic CO$_2$ sequestration, the soil moisture would need to be maintained lower than that of the study plot to preclude dissolving precipitated calcite. For many drylands, irrigation could be achieved by using fossil water reserves. These measured values demonstrate the relatively high potential carbon sequestration in Mediterranean drylands forests under irrigated and non-irrigated conditions.

physics.geo-ph

Potential Global Sequestration of Atmospheric Carbon Dioxide by Drylands Forestation

Drylands forestation offers the potential for significant long-term sequestration of atmospheric CO$_2$. We consider sequestration of organic and inorganic carbon by a planted semi-arid forest, based on carbon that originates from atmospheric CO$_2$. Measurements at Israels Yatir forest give a sequestration rate of $\sim$550 g CO$_2$ m$^{-2}$ yr$^{-1}$ as organic carbon in the trees biomass. The inorganic carbon precipitation rate gives an additional 216 g CO$_2$ m$^{-2}$ yr$^{-1}$ globally, via calcite (CaCO$_3$) precipitation in soil. This sequestration is due to a combination of microbial activity on organic soil carbon, and the formation of soil carbonic acid (H$_2$CO$_3$) that arises from the reaction of soil water with CO$_2$ exhaled from tree roots. Published estimates restrict the potential drylands surface available for sustainable forestation to $\sim$4.5 million km$^2$, only $\sim$10$\%$ of the global drylands. The dominant limitation is the apparent lack of water. However, immediately under many drylands, there are paleowaters (fossil water) that had recharged underlying aquifers during prior wetter climatic regimes. Conservatively, including fossil water, at least $\sim$9.0 million km$^2$ is available for afforestation. Measurements at Yatir show that drip irrigation to $\sim$18$\%$ average Soil Moisture (higher than the rainfed $\sim$12$\%$ SM) would double the organic carbon sequestration rate. In addition, the tree density could be increased, which would independently double the organic carbon sequestration rate. The potential total annual sequestration rate is then estimated as 20.0 Gt CO$_2$. Measurements at Israels Yatir forest give a sequestration rate of $\sim$20.0 Gt CO$_2$ yr$^{-1}$, divided between 14.0 Gt CO$_2$ yr$^{-1}$ (organic) and 6.0 Gt CO$_2$ yr$^{-1}$ (inorganic). This corresponds to $\sim$100$\%$ of the annual rate of atmospheric CO$_2$ increase.

physics.geo-ph

Sequestration of atmospheric carbon dioxide as inorganic carbon in the unsaturated zone under semi-arid forests

Inorganic carbon, in the form of allogenic (transported) and pedogenic (soil) carbonates in semi-arid soils, may comprise an important carbon sink. Carbon dioxide, CO2, originating from the atmosphere and exhaled by tree roots into the soil, may be hydrated by soil water within the unsaturated zone (USZ) of semi-arid soils to produce the carbonic acid (H2CO3) solutes HCO3- bicarbonate and H+ Hydrogen ion. This H+ may then dissolve relict soil CaCO3 carbonate (calcite), to release Ca+2 calcium cations and more HCO3- bicarbonate. When conditions allow, one mole of Ca+2 and two moles of HCO3- combine to precipitate one mole of calcite, and to release one mole of CO2: Ca+2 + 2HCO3- --> CaCO3 + CO2 + H2O. However, it has been claimed that such carbonates do not sequester significant amounts of present day atmospheric CO2. The reasons given were that they originate in part from the pre-existing limestone; and that for every mole of calcite precipitated, one mole of CO2 may be liberated to the atmosphere. It was argued that only if the Ca+2 cation is derived from a non-carbonate source can sequestration be assumed. We have tested these assumptions under field conditions at two semi-arid sites in Israel. We found that bicarbonate, originating from root exhalation, is depleted and is incorporated within the USZ as carbonates precipitate. Thus, a net sequestration of atmospheric CO2 does occur under semi-arid forests. Moreover, most of the CO2 liberated in the precipitation reaction may remain in the soil. And Ca+2 in the sediment may also be supplied from sources other than pre-existing calcite. Forestation can therefore augment pedogenic carbonate formation. By extrapolating our data globally, we suggest that worldwide semi-arid forests (existing and to be planted) may sequester 5-20% of the current annual anthropogenic increase of atmospheric carbon dioxide as pedogenic carbonate.

physics.geo-ph