Bryozoan skeletal mineralogy and ocean acidification

Project summary

• Focus: investigating the timing of biomineral switches in Late Cretaceous bryozoans and their relationship to changing seawater chemistry

Museum scientists are investigating the timing of a switch towards aragonite skeletons in certain Late Cretaceous bryozoans, and the relationship of this switch to changing seawater chemistry.

Cheilostome bryozoans use two calcium carbonate biominerals to form their skeletons:

• calcite
• aragonite

Investigating the switch to aragonite

Calcite is the primitive biomineral for cheilostomes but since the Late Cretaceous several clades have switched to partly or completely aragonitic skeletons.

We are investigating the timing of these switches and their relationship to changing seawater chemistry.

Investigating ocean acidification effects

The biomineral used also has relevance in the context of contemporary ocean acidification as aragonite is substantially more soluble than calcite.

In collaboration with a group from ENEA, La Spezia, Italy, we are studying the effects of acidification on bryozoan colonies deployed at a site near Naples where venting of volcanic carbon dioxide increases acidity on the seabed.