The quantification of heat and mass flow between deep reservoirs and the surface is important for understanding magmatic and hydrothermal systems. Here, we use high-resolution measurement of carbon dioxide flux (uCO 2 ) and heat flow at the surface to characterize the mass (CO 2 and steam) and heat released to the atmosphere from two magma-hydrothermal systems. Our soil gas and heat flow surveys at Rotokawa and White Island in the Taup o Volcanic Zone, New Zealand, include over 3000 direct measurements of uCO 2 and soil temperature and 60 carbon isotopic values on soil gases. Carbon dioxide flux was separated into background and magmatic/hydrothermal populations based on the measured values and isotopic characterization. Total CO 2 emission rates (RCO 2 ) of 441 6 84 Island, demonstrating that earlier research underestimated emissions by 700% (Rotokawa) and 25% (White Island). These differences suggest that soil CO 2 emissions facilitate more robust estimates of the thermal energy and mass flux in geothermal systems than traditional approaches. Combining the magmatic/hydrothermal-sourced CO 2 emission (constrained using stable isotopes) with reservoir H 2 O:CO 2 mass ratios and the enthalpy of evaporation, the surface expression of thermal energy release for the Rotokawa hydrothermal system (226 MW t ) is 10 times greater than the White Island crater floor (22.5 MW t ).

The fecundity of chinook salmon (Oncorhynchus tshawytscha) was estimated from maturing fish captured by anglers in the lower Waitaki River in 1985 and 1987-89, and from mature fish spawned at the Glenariffe Research Station on the Rakaia River in 1992. Fecundity was positively correlated with fork length (FL); estimated fecundities at 750 mm FL were 5024 eggs for Waitaki and 4829 eggs for Glenariffe salmon. The slopes of the regressions of fecundity on FL differed between the populations but the Glenariffe data did not differ from Rakaia River samples from 1967, 1973, and 1976. Significant inter-annual variation in the FLfecundity relationship was detected in Waitaki River samples. Egg weights, taken from the Glenariffe samples, were positively correlated with length and averaged 0.17 g. However, salmon with high fecundity for their FL tended to have small eggs, and vice versa.

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