Biogenic Acidification Reduces Sea Urchin Gonad Growth and Increases Susceptibility of Aquaculture to Ocean Acidification

摘要: Decreasing oceanic pH (ocean acidification) has emphasised the influence of carbonate chemistry on growth calcifying marine organisms. However, calcifiers can also change surrounding seawater through respiration and calcification, a potential limitation for aquaculture. This study examined how exchange rate stocking density sea urchin Tripneustes gratilla that were reproductively mature affected system parameters their culture water, which in turn influenced growth, gonad production condition. Growth, relative spine length, consumption rates reduced by up to 67% increased (9-43 individuals.m(-2)) (3.0-0.3 exchanges.hr(-1)), but survival food conversion efficiency unaffected. Analysis indicated calcite saturation state (ΩCa) primary factors limiting growth. Uptake bicarbonate release respiratory CO2 T. gratilla changed water. Importantly total alkalinity (AT) was reduced, likely due calcification urchins. Low AT limits capacity water buffer against acidification. Direct management counter biogenic acidification will be required maintain productivity reproductive output calcifiers, especially as ocean is altered climate driven