Sensitivity towards elevated &amp;lt;i&amp;gt;p&amp;lt;/i&amp;gt;CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; in great scallop (&amp;lt;i&amp;gt;Pecten maximus&amp;lt;/i&amp;gt; Lamarck) embryos and fed larvae

Sissel Andersen,Ellen S Grefsrud,Torstein Harboe

doi:10.5194/bg-14-529-2017

Sensitivity towards elevated &lt;i&gt;p&lt;/i&gt;CO&lt;sub&gt;2&lt;/sub&gt; in great scallop (&lt;i&gt;Pecten maximus&lt;/i&gt; Lamarck) embryos and fed larvae

Sissel Andersen, Ellen S Grefsrud + Show 1 more

Open Access

https://doi.org/10.5194/bg-14-529-2017

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Abstract

Abstract. The increasing amount of dissolved anthropogenic CO2 has caused a drop in pH values in the open ocean known as ocean acidification. This change in seawater carbonate chemistry has been shown to have a negative effect on a number of marine organisms. Early life stages are the most vulnerable, and especially the organisms that produce calcified structures in the phylum Mollusca. Few studies have looked at effects on scallops, and this is the first study presented including fed larvae of the great scallop (Pecten maximus) followed until day 14 post-fertilization. Fertilized eggs from unexposed parents were exposed to three levels of pCO2 using four replicate units: 465 (ambient), 768 and 1294 µatm, corresponding to pHNIST of 7.94, 7.75 (−0.19 units) and 7.54 (−0.40 units), respectively. All of the observed parameters were negatively affected by elevated pCO2: survival, larval development, shell growth and normal shell development. The latter was observed to be affected only 2 days after fertilization. Negative effects on the fed larvae at day 7 were similar to what was shown earlier for unfed P. maximus larvae. Growth rate in the group at 768 µatm seemed to decline after day 7, indicating that the ability to overcome the environmental change at moderately elevated pCO2 was lost over time. The present study shows that food availability does not decrease the sensitivity to elevated pCO2 in P. maximus larvae. Unless genetic adaptation and acclimatization counteract the negative effects of long term elevated pCO2, recruitment in populations of P. maximus will most likely be negatively affected by the projected drop of 0.06–0.32 units in pH within year 2100.

Highlights

The Intergovernmental Panel on Climate Change (IPCC) affirms that the uptake of anthropogenic CO2 in the ocean has very likely caused elevated seawater CO2 levels and thereby lowered the average oceanic pH values, termed ocean acidification (IPCC, 2013)
The present study shows the effects of elevated pCO2 on Pecten maximus embryos and fed larvae during a 14-day period, approximately two-thirds of the larval life cycle
Scallop embryos and larvae seem highly sensitive to elevated pCO2 at a very early stage in life

Summary

Introduction

The Intergovernmental Panel on Climate Change (IPCC) affirms that the uptake of anthropogenic CO2 in the ocean has very likely caused elevated seawater CO2 levels and thereby lowered the average oceanic pH values, termed ocean acidification (IPCC, 2013). A great effort is initiated worldwide to increase our knowledge of how ocean acidification affect coastal marine organisms; producing growing evidence that a high number of species respond negatively to exposure to elevated CO2 levels (Kroeker et al, 2013). Calcifying organisms seem to be more sensitive to elevated CO2 than non-calcifying organisms, and early life stages are more sensitive than older individuals (Byrne, 2012). Especially mussels and oysters, have reported negative effects on the pelagic early life stages (Gazeau et al, 2013; Kroeker et al, 2013; Parker et al, 2013).

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