Results

Ocean acidification can have a dramatic impact on early development

Example 1: Impact of Ocean Acidification on Survival and Development.

In brittlestars, a decrease in pH has a significant impact on survival and development (abnormal & asymmetric). In Ophiothrix fragilis, 100% mortality is observed after 8 days in conditions that mimic those expected in the next 100 years (Dupont et al., 2008).

Impact of Ocean Acidification is species-specific

It is clear that effects are species specific and even quite closely related species exhibit differing responses to reduce pH. For example while Ophiothrix (example 1) shows 100% mortality after 8 days, another brittlestar, Amphiura filiformis shows some malformations but survival till juvenile stage of around 20%.

Ocean acidification will not only induce calcification problems

Example 2: Impact of Ocean Acidification on development dynamics

In urchins, an affect on the temporal dynamics of development is seen rather than an affect on survival. For example in Strongylocentrotus drobachiensis the adult rudiment is well developed at 24 days post fertilization at normal pH 8.1 while at pH 7.9 the rudiment is smaller at 24 days pf and at pH 7.7 no clear rudiment is seen at 24 days pf. Thus under these conditions development appears to be normal but temporally delayed. However, there are other affects (see below).

Although development is apparently only delayed in urchins there is an effect on feeding. Those larvae reared at low pH show reduced feeding ability.

Example 3: Impact of Ocean

Acidification on feeding and digestion

Using confocal microscopy, we are able to visualize the food into the digestive track of living larvae. In this picture, you can see the living cells of the red algae Rhodomonas spp. (green) inside the stomach of a 4 days pluteus larvae of the sea urchin Strongylocentrotus purpuratus. Digested algae appear pigmented orange in the stomach, undigested algae remain green so we can estimate both ingestion and digestive efficiency.

Marine Acidification – On effects and monitoring of marine acidification in the seas surrounding Sweden
Pia Andersson, Bertil Håkansson, Johan Håkansson, Elisabeth Sahlsten, Jonathan Havenhand, Mike Thorndyke & Sam Dupont
The Swedish National Environmental Protection Agency - Oceanography No 92 – 2008

This report has been commissioned and funded by the Swedish Environmental Protection Agency to assess the need, how and where to monitor marine acidification in the seas surrounding Sweden.

download

CO₂-driven acidification radically affects larval survival and development in marine organisms
Sam Dupont, Jonathan Havenhand & Mike Thorndyke

Poster presentation at the "Effects of Climate Change on the World's Oceans" conference in Gijòn (May 2008)

download the poster