EFFECT OF A NATURAL CO2 GRADIENT ON EGG CHARACTERISTICS OF Arbacia lixula

ALFONSO, B.; HERNÁNDEZ, J.C.; HERNÁNDEZ, C.A.; GONZÁLEZ-DELGADO, S.; EPHERRA, L.

Nagoya

Conferencia; 16th International Echinoderm Conference; 2018

Nagoya University Museum

Until recently, the effects of ocean acidification (OA) in echinoderm reproduction have been studied under laboratory experimental condition. With the discovery of a natural CO2 vent in La Palma (Canary Island), the opportunity to study the reproduction and other live stages of species adapted to future conditions is possible. This vent system, with exceptional features such as an average pH of 7.6, shallow waters and no bubbles, allows the study of the future oceans. The aim of this study was to know the effects of a natural pH gradient on the density of eggs of the echinoderm species Arbacia lixula. To do this, A. lixula individuals were collected in four sites at different distances from the vent center. A 2ml injection of KCl was given to each one in the perivisceral cavity to induce spawning. The females that spawned in a 100ml pot were selected, and female eggs were counted with Sedgewick-rafter counting chamber. Also, eggs size was calculated with photo-analyses software. In the present work, significant changes in the number of A. lixula eggs due to the natural pH gradient is observed. Near the vent site, the number of eggs per female decreased significantly. Meanwhile, the egg size was similar between sites. Here, a new survival strategy of Arbacia lixula is shown. With a decrease in the number of eggs, this species of sea urchin is investing more energy in other metabolic processes to live in acidified environments. We demonstrated another change that will occur on A. lixula in the future if the current trend of climate change stays on