Antagonistic Effects of Ocean Acidification and Rising Sea Surface Temperature on the Dissolution of Coral Reef Carbonate Sediments
نویسندگان
چکیده
Increasing atmospheric CO2 is raising sea surface temperature (SST) and increasing seawater CO2 concentrations, resulting in a lower oceanic pH (ocean acidification; OA), which is expected to reduce the accretion of coral reef ecosystems. Although sediments comprise most of the calcium carbonate (CaCO3) within coral reefs, no in situ studies have looked at the combined effects of increased SST and OA on the dissolution of coral reef CaCO3 sediments. In situ benthic chamber incubations were used to measure dissolution rates in permeable CaCO3 sands under future OA and SST scenarios in a coral reef lagoon on Australia’s Great Barrier Reef (Heron Island). End of century (2100) simulations (temperature +2.7C and pH −0.3) shifted carbonate sediments from net precipitating to net dissolving. Warming increased the rate of benthic respiration (R) by 29% per 1C and lowered the ratio of productivity to respiration (P/R; 1P/R = −0.23), which increased the rate of CaCO3 sediment dissolution (average net increase of 18.9 mmol CaCO −2 −1 3 m d for business as usual scenarios). This is most likely due to the influence of warming on benthic P/R which, in turn, was an important control on sediment dissolution through the respiratory production of CO2. The effect of increasing CO2 on CaCO3 sediment dissolution (average net increase of 6.5 mmol CaCO3 m −2 d−1 for business as usual scenarios) was significantly less than the effect of warming. However, the combined effect of increasing both SST and pCO2 on CaCO3 sediment dissolution was non-additive (average net increase of 5.6 mmol CaCO3 m −2 d−1) due to the different responses of the benthic community. This study highlights that benthic biogeochemical processes, such as metabolism and associated CaCO3 sediment dissolution respond rapidly to changes in SST and OA, and that the response to multiple environmental changes are not necessarily additive.
منابع مشابه
Effects of ocean acidification on the dissolution rates of reef-coral skeletons
Ocean acidification threatens the foundation of tropical coral reefs. This study investigated three aspects of ocean acidification: (i) the rates at which perforate and imperforate coral-colony skeletons passively dissolve when pH is 7.8, which is predicted to occur globally by 2100, (ii) the rates of passive dissolution of corals with respect to coral-colony surface areas, and (iii) the compar...
متن کاملA fundamental paradigm for coral reef carbonate sediment dissolution
The long-term success of coral reefs depends on a positive balance of calcium carbonate production exceeding dissolution, erosion, and material export. As a result of ocean acidification, coral reefs could transition from net accretion to net erosion owing to decreasing rates of calcification and increasing rates of chemical dissolution and bioerosion. Here, I present a fundamental paradigm tha...
متن کاملOcean Acidification Changes Abiotic Processes but Not Biotic Processes in Coral Reef Sediments
In coral reefs, sediments play a crucial role in element cycling by contributing to primary production and the remineralization of organic matter. We studied how future ocean acidification (OA) will affect biotic and abiotic processes in sediments from two coral reefs of the Great Barrier Reef, Australia. This was investigated in the laboratory under conditions where water-sediment exchange was...
متن کاملModelling coral calcification accounting for the impacts of coral bleaching and ocean acidification
Coral reefs are diverse ecosystems that are threatened by rising CO2 levels through increases in sea surface temperature and ocean acidification. Here we present a new unified model that links changes in temperature and carbonate chemistry to coral health. Changes in coral health and population are explicitly modelled by linking rates of growth, recovery and calcification to rates of bleaching ...
متن کاملInteractions between Ocean Acidification and Warming on the Mortality and Dissolution of Coralline Algae(1).
Coralline algae are among the most sensitive calcifying organisms to ocean acidification as a result of increased atmospheric carbon dioxide (pCO2 ). Little is known, however, about the combined impacts of increased pCO2 , ocean acidification, and sea surface temperature on tissue mortality and skeletal dissolution of coralline algae. To address this issue, we conducted factorial manipulative e...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2016