California mussels: 1st warming casualty?

The iconic California mussel could be among the first casualties of oceans made more acidic by global warming, a new study of the coastal shellfish shows.

Scientists who grew mussel larvae in a bath of acidified water thought to match expected changes in ocean chemistry report thinner, weaker shells and smaller bodies in a newly published study.

“We’re interested in the California mussel because it is an ecologically critical species, familiar to many of us who live along the West Coast,” said Brian Gaylord, evolution and ecology professor at the UC Davis Bodega Marine Laboratory. “It provides habitat, refuge, and provides food for over 300 other species.”

L’autre problème du CO2 (movie, in French)

Le dessin animé produit par les élèves de l’école Ridgeway de Plymouth (Royaume-Uni) et les chercheurs du Laboratoire Marin de Plymouth (financé par EPOCA) vient d’être traduit en français par des élèves du collège Charles III de Monaco avec le soutien d’EPOCA et de l’Institut océanographique de Monaco. Il est disponible sur YouTube.

Effect of ocean acidification on early life stages of Atlantic herring (Clupea harengus L.)

Due to atmospheric accumulation of anthropogenic CO₂ the partial pressure of carbon dioxide (pCO₂ in surface seawater increases and the pH decreases. This process known as ocean acidification might have severe effects on marine organisms and ecosystems. The present study addresses the effect of ocean acidification on the early developmental stages, the most sensitive stages in the life history, of the Atlantic herring (Clupea harengus L.). Eggs of the Atlantic herring were fertilized and incubated in artificially acidified seawater (pCO₂ 1260, 1859, 2626, 2903, 4635 μatm) and a control treatment (pCO₂ 480 μatm) until the main hatch of herring larvae occurred. The development of the embryos was monitored daily and newly hatched larvae were sampled to analyze their morphometrics, and their condition by measuring the RNA/DNA ratios. Elevated pCO₂ neither affected the embryogenesis nor the hatch rate. Furthermore the results showed no linear relationship between pCO₂ and total length, dry weight, yolk sac area and otolith area of the newly hatched larvae. For pCO₂ and RNA/DNA ratio, however, a significant negative linear relationship was found. The RNA concentration at hatching was reduced at higher pCO₂ levels, which consequently should lead to a decreased protein biosynthesis. The results indicate that an increased pCO₂ can affect the metabolism of herring embryos negatively. Accordingly, further somatic growth of the larvae could be reduced. This can have consequences for the larval fish, since smaller and slow growing individuals have a lower survival potential due to lower feeding success and increased predation mortality. The regulatory mechanisms necessary to compensate for effects of hypercapnia could therefore lead to lower larval survival and could affect the ecosystem and fisheries. Since the recruitment of fish seems to be determined during the early life stages, future research on the factors influencing these stages are of great importance in fisheries science.