Anomalies in the radial concentration trends of Ca2+, Mg2+, and other divalent cations in the stemwood of red spruce (Picearubens Sarg.) occurred in trees grown in New England, Tennessee, and North Carolina. These anomalies may be assumed to result from changes in sap chemistry. These inferred changes in sap chemistry were the expected result of changes of divalent cation availability in forest soils. The patterns of these anomalies may be interpreted as a signal of a regional mobilization of cations in the rooting zone of red spruce. The anomalous increase in divalent cations present in wood formed in the mid-1900s is coincident both with rapid increases in SOx and NOx deposition in eastern North America and with increases in radial growth increment. The anomalous decrease in divalent cations in wood formed in the late-1900s is coincident with declines in radial increment. Comparisons with divalent cation trends in eastern hemlock (Tsugacanadensis (L.) Carr.), Fraser fir (Abiesfraseri (Pursh) Poir.), and yellow birch (Betulaalleghaniensis Britt. = B. lutea Michx.) suggested that these anomalies were not restricted to red spruce. Radial concentration trends of 90Sr introduced to the environment through radioactive fallout during the 1950s and 1960s were used to investigate the physiology of these divalent cation concentration anomalies. The distributions of 90Sr were also used to estimate the turnover rates for the nutritionally available pools of alkaline earths such as calcium.

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Abstract.The thermohaline circulation system in the Japan Sea, an almost land-locked marginal sea in the northwest Pacific, is now in a transition state. Comparison of vertical profiles of tritium, oxygen and nutrients between 1984 and 1998 demonstrates the following two points: (1) the supply of dense surface seawater to the bottom layer (>2,500 m in depth) has almost ceased since 1984, and (2) the intrusion of surface seawater to an intermediate depth range (between -700 m and -2,000 m in depth) has been reinforced during this 14-year period. Such transitional upward shift of the thermohaline conveyor belt in the Japan Sea is thought to have separeted the bottom water from the conveyor belt and brought about a stagnant mode of the bottom water.

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The objectives of this study were to investigate the distribution and chemical characteristics of cations in annual rings of Japanese cedar (Cryptomeriajaponica D. Don) grown in a healthy stand of an unindustrialized region in Japan and discuss the possibility of using cations in tree-rings as a chronological index of acidic deposition. Radial distributions of some cations and P at different vertical positions of the stem were analyzed for five trees from the same mountain. Each cation and P in all trees showed a specific distribution in its radial pattern but similar distribution trends were observed at all vertical positions. The cations and P were classified into three groups: (I) constant radial concentrations (Ca 2 + , Sr 2 +, Na ÷ , and probably Ba 2 +), (II) high concentrations in the heartwood and low in the sapwood (Mg +, K + , Rb ÷ , Cs +), and (IH) increasing concentrations in sapwood (P, Mn z ÷, Cũ +). The total concentration of cations exceeded the calcium-binding capacity (CBC) of the wood, and the excess was attributed to K + in a salt form. The CBC increased from the sapwood/ heartwood boundary toward the pith in the heartwood but remained constant in the sapwood. The increase of CBC in the heartwood was consistent with the profile of Mg 2+ , indicating a transfer of Mg + into heartwood and fixation on the acquired binding site. The radial distribution of 9°Sr was closely related to the cumulative deposition of fallout from the nuclear weapon tests, but that of ~TCs was unrelated. This suggests immobility of Sr~ + and mobility of Cs ÷ in the horizontal direction of wood. The conservation of the historical ~eSr/Sr2 + change indicated that no influence of heartwood formation on the chemical environment of Sr~+ in cedar xylem and a possibility of using Sr + as a chronological index of nutrient availability. A steady-state in nutrient availability is speculated for trees growing in this mountain because all of the trees analyzed show constant radial distributions of Sr 2 + for decades.