The bulk-representative low-energy spectrum of Sr2RuO4 can be directly measured by angle-resolved photoemission. We find that the quasiparticle spectral line shape of Sr2RuO4 is sensitive to both temperature and momentum. Along the (0, 0)-(π, 0) direction, both gamma and ß bands develop a sharp quasiparticle peak near kF at low temperatures, but as the temperature increases the spectra quickly lose coherent weight and become broad backgrounds above ~130 K, which is the metal-nonmetal crossover temperature, TM, in the c-axis resistivity. However, spectra along the (0, 0)-(π, π) direction evolve smoothly across TM. A simple transport model can describe both in-plane and c-axis resistivity in terms of the quasiparticle line shape. Comparisons are also made to the cuprates, with implications for two dimensionality, magnetic fluctuations, and superconductivit
