Information From Skeletons:
Carbonate Sedimentary Systems

Shell-producing organisms which live in the sea may record aspects of their environment in their skeletal carbonate. We explore aspects of the cool-water carbonate budget -- production, geochemistry, and destruction of biogenic carbonate on the temperate shelf.

We are looking at the potential of different marine taxa (especially bryozoans) as geochemical "thermometers," the fate of marine carbonate in temperate shelf sediments, and overall growth and production rates for a variety of skeletal taxa, both tropical and temperate.

This work is taking on new importance in the context of Ocean Acidification, and our newest projects are looking at bryozoans as carbonate saturometers.

People: Carbonate Sedimentary Systems

Associate Professor Abigail M. Smith ( Marine Science)

Research Students

Anna Wood Gearoid O'Sullivan Christine Davis Marc Reidi

Projects: Carbonate Sedimentary Systems

• Bryozoans and their importance in predicting effects of acidification -- Abigail Smith, Will Howard, others
• A carbonate budget for Otago Harbour -- Abigail Smith, Anna Wood, Amy Shears
• Bimineral carbonate in a temperate bryozoan: Odontionella cyclops -- Abigail Smith
• Aspect of the bryozoan family Horneridae in New Zealand -- Abigail Smith, Dennis Gordon, Paul Taylor
  
• Genetics of cyclostome bryozoans from New Zealand -- Abigail Smith, Jo Porter, others
  
• Biomineralisation in invertebrates -- Abigail Smith, Miles Lamare, Jade Berman, others
  
• Bryozoan carbonate: a temperate record of seawater chemistry-- Abigail Smith, Marcus M. Key, Jr.
  
• Subtidal serpulid reefs in Paterson Inlet, Stewart Island -- Gearoid O'Sullivan, Keith Probert, Abigail Smith,
  
• Early sea-floor processes and their effects on temperate carbonate deposits -- Abigail Smith, Cam Nelson
  
• Spaces among the bryozoans: epifauna in the Otago bryozoan meadows - Anna Wood, Keith Probert, Abigail Smiht
  
• A sediment budget for Otago Harbour -- Amy Shears, Andrew Gorman, Abigail Smith
  
• Settlement and growth in Bugula flabellata in Otago -- Christine Davis, Abigail Smith
  

Research Projects Available to MSc and PhD students

Calcification in coralline algae
Calcifying red algae are abundant and important coastal marine organisms, both here and overseas. What minerals do they form, and how is is related to where they live? And especially, what happens to their skeletons after death?  They appear to be very poorly represented in New Zealand's carbonate sediments, despite being abundant intertidal organisms. This project would involve field work as well as experiments with fragmentation and skeletal composition.

Fragmentation in temperate invertebrates
When hard-shelled organisms die, their shells become vulnerable to abrasion and breakage. Processes of fragmentation of carbonate in temperate environments are mostly unknown, and could be investigated using lab experiments to quantify and understand variation in destructive processes on the continental shelf. How do different kinds of shells break down? Which are most likely to be fossilised?

Carbonate production in serpulid worms
Serpulid tube worms live all over New Zealand, from the intertidal to deeper shelf waters. They form carbonate tubes in which to live, sometimes remarkably fast. How fast do they mineralise, and what are the tubes made of? Lab work, field work, diving, cruising, travel - worms can provide it all.

In situ carbonate saturometry
The pH of shallow marine waters is decreasing due to anthropogenic CO2 emissions. How might ocean acidification affect marine temperate carbonate sediments? We don't even know what levels of dissolution occur now, or where. This project involves developing and using new techniques for measuring carbonate dissolution at and near the sediment-seawater interface. Field, lab, diving are all important.