Meeting Abstract
Sea surface pH is projected to decline 0.3 units from current conditions by the year 2010 (ocean acidification, OA). In the same timespan, global surface temperature is expected to increase up to 5°C (ocean warming, OW). Intertidal zone organisms, which are adapted to variable and extreme environments, may already be living at their tolerance limits, and OA and OW may be physiologically stressful. Few studies have examined the integrated effects of growth on juvenile organisms under such conditions, as juvenile growth has been shown to be negatively impacted by both OA and OW. Previous research on adult Petrolisthes cinctipes showed that OA and OW conditions resulted in metabolic depression and increased thermal tolerance. However, it was unclear how ATP energy was allocated under OA and OW conditions. We asked: is ATP energy expenditure affected in growth processes of juvenile P. cinctipes while experiencing future OA and OW conditions? We hypothesized that ATP energy supply to growth processes would decrease, and therefore, juvenile P. cinctipes growth rates would slow under OA and OW conditions. To simulate year 2100 conditions, we have conducted a multi-stressor experiment to assess growth in response to OA and OW. Juvenile P. cinctipes were exposed for 35 days to four hours of either future OA (pH 7.3) or ambient (pH 8.0) conditions while immersed, and five hours of either a temperature spike to 25°C or ambient temperature (14°C) while emersed. Initial mortality data may indicate an increase in temperature may exacerbate mortality under acidic conditions. In addition, growth may be hindered in OA conditions, and may be exacerbated in combination with OW. These results may suggest that ATP energy may be diverted from growth to compensate for the physiological processes needed for survival in OA and OW conditions.
