Article

Ocean acidification may increase calcification rates, but at a cost.

Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth PL1 3DH, UK.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.29). 09/2008; 275(1644):1767-73. DOI: 10.1098/rspb.2008.0343
Source: PubMed

ABSTRACT Ocean acidification is the lowering of pH in the oceans as a result of increasing uptake of atmospheric carbon dioxide. Carbon dioxide is entering the oceans at a greater rate than ever before, reducing the ocean's natural buffering capacity and lowering pH. Previous work on the biological consequences of ocean acidification has suggested that calcification and metabolic processes are compromised in acidified seawater. By contrast, here we show, using the ophiuroid brittlestar Amphiura filiformis as a model calcifying organism, that some organisms can increase the rates of many of their biological processes (in this case, metabolism and the ability to calcify to compensate for increased seawater acidity). However, this upregulation of metabolism and calcification, potentially ameliorating some of the effects of increased acidity comes at a substantial cost (muscle wastage) and is therefore unlikely to be sustainable in the long term.

0 Bookmarks
 · 
108 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Anthropogenic CO2 emissions have caused seawater temperature elevation and ocean acidification. In view of both phenomena are occurring simultaneously, their combined effects on marine species must be experimentally evaluated. The purpose of this study was to estimate the combined effects of seawater acidification and temperature increase on the energy budget of the thick shell mussel Mytilus coruscus. Juvenile mussels were exposed to six combined treatments with three pH levels (8.1, 7.7 and 7.3)×two temperatures (25°C and 30°C) for 14d. We found that clearance rates (CRs), food absorption efficiencies (AEs), respiration rates (RRs), ammonium excretion rates (ER), scope for growth (SFG) and O:N ratios were significantly reduced by elevated temperature sometimes during the whole experiments. Low pH showed significant negative effects on RR and ER, and significantly increased O:N ratios, but showed almost no effects on CR, AE and SFG of M. coruscus. Nevertheless, their interactive effects were observed in RR, ER and O:N ratios. PCA revealed positive relationships among most physiological indicators, especially between SFG and CR under normal temperatures compared to high temperatures. PCA also showed that the high RR was closely correlated to an increasing ER with increasing pH levels. These results suggest that physiological energetics of juvenile M. coruscus are able to acclimate to CO2 acidification with a little physiological effect, but not increased temperatures. Therefore, the negative effects of a temperature increase could potentially impact the ecophysiological responses of M. coruscus and have significant ecological consequences, mainly in those habitats where this species is dominant in terms of abundance and biomass. Copyright © 2015 Elsevier B.V. All rights reserved.
    Science of The Total Environment 02/2015; 514C:261-272. DOI:10.1016/j.scitotenv.2015.01.092 · 3.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Anthropogenic emissions cause the global CO2 partial pressure (pCO2) to increase, and atmospheric models predict a pCO2 of ~1,000 µatm by the year 2100. About one-third of emitted CO2 is absorbed by the world's oceans, causing a decrease in ocean pH. Experiments show varying effects of this so-called ocean acidification (OA) on marine animals, and it has proven exceedingly difficult to establish general rules for OA effects among species. In the present study, we found different energetic OA effects in populations from Svalbard and Skagerrak of the same calanoid copepod species, Pseudocalanus acuspes. In the Svalbard population, ingestion rates showed an inverted U-shaped hormesis-like response with higher rates at pH 7.80 than at pH 7.95 and pH 7.61 at medium and high prey concentrations. On the other hand, ingestion rates were lower at pH 7.70 and pH 7.47 than at pH 7.95 only at high prey concentrations in the Skagerrak population. Secondly, we found significant interactions between the effects of pH and prey concentration on both ingestion rate and respiration rate in the Skagerrak population, which indicates that OA may influence the way ingestion and respiration relate to prey concentration. In conclusion, the results suggest that OA effects may be far from linearly related to pH in copepods, and moreover, the effects may vary within species between populations from different regions.
    Marine Biology 01/2015; DOI:10.1007/s00227-015-2625-9 · 2.39 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Surface seawaters are becoming more acidic due to the absorption of rising anthropogenic CO 2. Marine calcifiers are considered to be the most vulnerable organisms to ocean acidification due to the reduction in the availability of carbonate ions for shell or skeletal production. Rhychonelliform brachiopods are potentially one of the most calcium carbonate-dependent groups of marine organisms because of their large skeletal content. Little is known, however, about the effects of lowered pH on these taxa. A CO 2 perturbation experiment was performed on the New Zealand terebratulide brachiopod Calloria inconspicua to investigate the effects of pH conditions predicted for 2050 and 2100 on the growth rate and ability to repair shell. Three treatments were used: an ambient pH control (pH 8.16), a mid-century scenario (pH 7.79), and an end-century scenario (pH 7.62). The ability to repair shell was not affected by acidified conditions with .80% of all damaged individuals at the start of the experiment completing shell repair after 12 weeks. Growth rates in undamaged individuals .3 mm in length were also not affected by lowered pH conditions, whereas undamaged individuals ,3 mm grew faster at pH 7.62 than the control. The capability of C. inconspicua to continue shell production and repair under acidified conditions suggests that this species has a robust control over the calcification process, where suitable conditions at the site of calcification can be generated across a range of pH conditions.
    ICES Journal of Marine Science 03/2015; DOI:10.1093/icesjms/fsv031 · 2.53 Impact Factor

Full-text

Download
56 Downloads
Available from
Jun 1, 2014