Previous studies have shown fertilization and development of marine species can be significantly inhibited when the pH of sea water is artificially lowered. Little mechanistic understanding of these effects exists to date, but previous work has linked developmental inhibition to reduced cleavage rates in embryos. To explore this further, we tested whether common cell cycle checkpoints were involved using three cellular biomarkers of cell cycle progression: (1) the onset of DNA synthesis, (2) production of a mitotic regulator, cyclin B, and (3) formation of the mitotic spindle. We grew embryos of the purple sea urchin, Strongylocentrotus purpuratus, in seawater artifically buffered to a pH of ~7.0, 7.5, and 8.0 by CO2 infusion. Our results suggest the reduced rates of mitotic cleavage are likely unrelated to common cell cycle checkpoints. We found no significant differences in the three biomarkers assessed between pH treatments, indicating the embryos progress through the G1/S, G2/M and metaphase/anaphase transitions at relatively similar rates. These data suggest low pH environments may not impact developmental programs directly, but may act through secondary mechanisms such as cellular energetics.
Archive for April 4th, 2012
Effects of seawater acidification on cell cycle control mechanisms in Strongylocentrotus purpuratus embryosPublished 4 April 2012 Science Leave a Comment
Tags: biological response, echinoderms
First evidence of immunomodulation in bivalves under seawater acidification and increased temperaturePublished 4 April 2012 Science Leave a Comment
Tags: biological response, mollusks
Water acidification, temperature increases and changes in seawater salinity are predicted to occur in the near future. In such a global climate change (GCC) scenario, there is growing concern for the health status of both wild and farmed organisms. Bivalve molluscs, an important component of coastal marine ecosystems, are at risk. At the immunological level, the ability of an organism to maintain its immunosurveillance unaltered under adverse environmental conditions may enhance its survival capability. To our knowledge, only a few studies have investigated the effects of changing environmental parameters (as predicted in a GCC scenario) on the immune responses of bivalves. In the present study, the effects of both decreased pH values and increased temperature on the important immune parameters of two bivalve species were evaluated for the first time. The clam Chamelea gallina and the mussel Mytilus galloprovincialis, widespread along the coast of the Northwestern Adriatic Sea, were chosen as model organisms. Bivalves were exposed for 7 days to three pH values (8.1, 7.7 and 7.4) at two temperatures (22 and 28°C). Three independent experiments were carried out at salinities of 28, 34 and 40 PSU. The total haemocyte count, Neutral Red uptake, haemolymph lysozyme activity and total protein levels were measured. The results obtained demonstrated that tested experimental conditions affected significantly most of the immune parameters measured in bivalves, even if the variation pattern of haemocyte responses was not always linear. Between the two species, C. gallina appeared more vulnerable to changing pH and temperature than M. galloprovincialis. Overall, this study demonstrated that climate changes can strongly affect haemocyte functionality in bivalves. However, further studies are needed to clarify better the mechanisms of action of changing environmental parameters, both individually and in combination, on bivalve haemocytes.
House Energy and Commerce Ranking Member Henry Waxman (D-CA) and Energy and Power Subcommittee Ranking Member Bobby Rush (D-IL) sent a letter March 21 to chairmen Fred Upton (R-MI) and Ed Whitfield (R-KY) asking that the committee hold a hearing on a March 2 Science article showing that CO2 deposition is causing oceans to acidify more rapidly than previously thought. Continue reading ‘Ocean acidification’
New report reveals concern, insecurity regarding ocean acidification among Alaska fishermen and coastal residentsPublished 4 April 2012 Media coverage Leave a Comment
A report released this week by a community-based fisheries group shows concern over the long-term impacts of ocean acidification on Alaska fisheries and livelihoods. The study by the Alaska Marine Conservation Council (AMCC) is based on community roundtable discussions held this winter in the fisheries-dependent communities of Homer, Kodiak, and Dillingham.
“Ocean acidification has the potential to significantly impact the health and productivity of Alaska’s oceans,” said Rachel Donkersloot, lead author of the study and Fisheries Program Director at AMCC. “While we don’t yet know exactly how ocean acidification will affect specific fisheries, we do know it’s a threat to marine habitat and the ocean food web which our economies and communities ultimately depend on. Fishermen and coastal Alaskans are concerned.”
A new conservation report culled from community discussions in Kodiak, Dillingham and Homer underscores concern for the health and productivity of oceans coastal communities depend on in the face of rising ocean acidification.
“The economic value of Alaska’s commercial fisheries approaches $4 billion (first wholesale value), but it is not known how ocean acidification will affect specific fisheries and what the cost will be to the seafood industry and fishery-dependent communities,” said report’s author, Rachel Donkersloot, fisheries program director for the Alaska Marine Conservation Council.