Regime shifts of hydrometeorological factors in the Jiaozhou Bay and their potential ecological impacts

The wavelet transform was applied to studying the regime shifts of hydrometeorological factors (i.e., precipitation, air temperature, sea surface temperature and sea surface salinity) during the period of 1961-2000 in the Jiaozhou Bay (JZB). The results indicated clearly that these factors show variability of multiple timescales, with interannual and decadal periods. The local abrupt changes such as the 1978-1979 and 1988-1989 shifts feature the physical environment variation, which is consistent with the Southern Oscillation and Arctic Oscillation in the northern hemisphere. In regard to the JZB ecosystem, the benthic diatom cell abundance (BEN) showed a decrease shift in 1978-1979, which is closely related to the precipitation abrupt decrease, while the shellfish mortality disaster in the JZB greatly released the predating pressure of diatom growth, possibly resulting in BEN increase shift in 1995.