Effect of terrestrial sediment on the burial behaviour of post-settlement Macomona liliana Aysha K. Hohaia A thesis submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Science (MSc) 2012 School of Applied Sciences Primary Supervisor: Dr. Kay C. Vopel Attestation of authorship “I hereby declare that this submission is my own work and that, to the best of my knowledge and belief, it contains no material previously published or written by another person (except where explicitly defined in the acknowledgements), nor material which to a substantial extent has been submitted for the award of any other degree or diploma of a university or other institution of higher learning.” Signed: Date: 07/06/2013 ii Table of contents Attestation of authorship ................................................................................................ ii Table of contents ............................................................................................................ iii List of figures ................................................................................................................... vi List of tables .................................................................................................................... vii Acknowledgements ......................................................................................................... ix Abstract ............................................................................................................................ x Introduction ..................................................................................................................... 1 Supply and land–ocean transfer of terrestrial sediment ............................................. 1 Effect of terrestrial sediment on ecosystem functioning ............................................ 3 Characteristics of terrestrial sediments ....................................................................... 3 Terrestrial sedimentation in New Zealand aquatic environments .............................. 4 Sediment biogeochemistry .......................................................................................... 8 Recruitment and porewater chemistry linkages ........................................................ 15 General biology of Macomona liliana ........................................................................ 17 Burial, crawling, and drifting behaviour of Macomona liliana .................................. 20 Hypothesis ................................................................................................................. 22 Material and methods ................................................................................................... 23 Sampling sites ............................................................................................................ 23 Intertidal sediment ................................................................................................ 26 Bivalves .................................................................................................................. 26 Depleted sediment ................................................................................................ 26 Terrestrial sediment ............................................................................................... 27 Experimental setup .................................................................................................... 27 Seawater flume ...................................................................................................... 27 Experimental sequence .......................................................................................... 29 iii Measurements and observations .............................................................................. 31 Flume seawater ..................................................................................................... 31 Sediment porewater .............................................................................................. 31 Data analyses ............................................................................................................. 32 Digital photographs ............................................................................................... 32 Sediment .................................................................................................................... 32 Terrestrial sediment deposit .................................................................................. 32 Intertidal and Depleted sediment .......................................................................... 33 Oxygenation ........................................................................................................... 33 Statistics ..................................................................................................................... 34 Results ............................................................................................................................ 35 Flume environment: seawater ................................................................................... 35 Flume environment: sediment .................................................................................. 37 Surface structure and colour ................................................................................. 37 Intertidal and depleted sediment .......................................................................... 39 Terrestrial sediment suspension ............................................................................ 39 Porewater solutes ...................................................................................................... 42 Oxygen ................................................................................................................... 44 pH ........................................................................................................................... 48 Redox ..................................................................................................................... 51 Macomona liliana size distribution ............................................................................ 54 Effect of treatment on Macomona liliana burial behaviour ...................................... 55 Macomona liliana behavioural responses ............................................................. 56 Discussion ...................................................................................................................... 61 Effect of terrestrial sediment deposition on porewater chemistry ........................... 61 Sediment oxygenation ........................................................................................... 62 iv Distribution of pH .................................................................................................. 63 Redox potential ...................................................................................................... 63 Effect of terrestrial sediment deposition on burial behaviour of Macomona liliana 64 Sediment preferences ............................................................................................ 65 Bioturbation context .................................................................................................. 66 Potential influence of flow ......................................................................................... 69 Appraisal of methodology .......................................................................................... 70 Conclusions .................................................................................................................... 73 References ..................................................................................................................... 74 Appendices .................................................................................................................... 88 Appendix 1 ................................................................................................................. 88 Appendix 2 ................................................................................................................. 89 Appendix 3 ................................................................................................................. 91 Appendix 4. ................................................................................................................ 96 v List of figures Figure 1. Satellite image (A, B, C) and an aerial photograph (D) showing sediment plumes of (A) the Betsiboka River, Madagascar (http://www.solarviews.com), (B) the Mississippi River, USA (http://visibleearth.nasa.gov), (C) Cook Straight, New Zealand (http://visibleearth.nasa.gov), and (D) the Waipaoa River, New Zealand (http://www.vims.edu) .................................................................................................... 2 Figure 2. Conceptual model of organic matter (OM) degradation pathways, modified from Glud (2008) and Middleburg and Levin (2009). Organic matter degradation involves hydrolysis of macromolecular organic matter and fermentation into smaller compounds. These fermentation products are used by respiring microorganisms and methanogens. Oxidants are utilised sequentially, first oxygen, then nitrate, metal oxides, and sulphate. Dissolved reduced products diffuse upwards and are then − 4+ 3+ 2− oxidised: NO3 , nitrate; Mn , manganese; Fe , iron; SO4