The role of marine wood borers in flows of carbon from woody detritus

Project code: BIOL2880217

This project is aimed at filling a major gap in our understanding of how carbon flows through healthy mangrove ecosystems, which are even better than rainforest in sequestering carbon in their soil/sediment. Marine borers process a significant portion of the carbon captured by mangrove photosynthesis, while contributing fragments and faeces to the soil carbon bank. This study aims to characterise and measure borer processing. Techniques to be used will include experimental rearing of borers, lab studies of feeding, NMR, HPLC, electron microscopy, stable isotope signature measurement and field surveys in mangrove ecosystems. Training will be provided at the Institute of Marine Sciences and at the molecular biology research labs at the University of Portsmouth. Experience at National facilities and with collaborating institutions is an integral part of this study.

In this study, we will investigate the isotopic signatures of borers reared under controlled conditions and sampled from the mangrove ecosystem to reveal their sources of C, S and N. The species selected will exemplify borers that digest wood without the aid of mutualistic microbes (isopod crustaceans) and those that have mutualists (teredinid molluscs). Teredinid species that also exploit phytoplankton and those that do not will be compared. This study will test the hypotheses that borers obtain carbon direct from wood, but that some also use other sources; that some obtain nitrogen from symbionts and others by grooming then ingesting epibiota.

Roughly half of pre-industrial mangrove forest area has been lost, much to prawn pond aquaculture, but rehabilitation of abandoned ponds to functioning forest ecosystems will contribute significantly to counterbalancing the huge contribution of deforestation to increasing atmospheric CO2 levels. Good models of carbon dynamics in mangrove ecosystems to which this study will contribute will guide initiatives that use carbon trading to encourage forest restoration under the REDD mechanism – a UN-sponsored initiative.