Poster Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

The role of macrofauna in shaping microphytobenthic communities (#608)

Duyi Zhong 1 , Katherine Dafforn 1 , Melanie Bishop 1
  1. Macquarie university, Marsfield, NSW, Australia

Mudflats in estuarine and coastal areas are of high ecological and socio-economic importance, underpinning food-webs, supporting fisheries, and providing shoreline protection. Central to these functions of mudflats are microphytobenthos (MPB) -- microscopic photosynthesizers at the base of the food web. Local and global environmental change has the potential to modify the productivity and community composition of MPB, both directly and also indirectly, by altering the identity and density of macrofauna – which consume MPB and disturb sediments. Through controlled aquarium experiments, this study investigated the independent and interactive effects of two macrobenthic species—Pyrazus ebeninus, a deposit feeder, and Trypaea australiensis, a burrower—on colonization of MPB, under scenarios of (no, low or high) nutrient enrichment. Effects of macrofauna on MPB were strongest at the low level of nutrient enrichment, with a lower chlorophyll a to phaeopigment ratio in the treatment with only Pyrazus than the other treatments (no animals, or Trypaea with or without Pyrazus), indicating species-specific effects of macrofauna. The results highlight the importance of macrofauna in shaping MPB, and the sensitivity of these interactions to environmental change. Disentangling these relationships will be important for estuarine ecosystem management in a changing environment.

  1. Alvarez M F, Esquius KS, Addino M, Alberti J, Iribarne O, Botto F, Cascading top-down effects on estuarine intertidal meiofaunal and algal assemblages, Journal of Experimental Marine Biology and Ecology, 440: 216-224(2013). https://doi.org/10.1016/j.jembe.2012.12.015.
  2. Barbier EB., Hacker SD., Kennedy C., Koch EW., Stier AC. and Silliman BR., The value of estuarine and coastal ecosystem services. Ecological Monographs, 81: 169-193 (2011). https://doi.org/10.1890/10-1510.1
  3. Bishop MJ., Kelaher BP, Sharp SM, Verhoeven M, Dispersal of the estuarine gastropod Pyrazus ebeninus is only weakly influenced by pneumatophore density, Journal of Experimental Marine Biology and Ecology:62-69(2007). https://doi.org/10.1016/j.jembe.2006.08.009.
  4. Kenworthy, J. M., Paterson, D. M., & Bishop, M. J. (2016). Response of benthic assemblages to multiple stressors: comparative effects of nutrient enrichment and physical disturbance. Marine Ecology Progress Series, 562, 37-51. https://doi.org/10.3354/meps11935
  5. Clark, D. E., Pilditch, C. A., Pearman, J. K., Ellis, J. I., & Zaiko, A. (2020). Environmental DNA metabarcoding reveals estuarine benthic community response to nutrient enrichment – Evidence from an in-situ experiment. Environmental Pollution, 267, 115472 https://linkinghub.elsevier.com/retrieve/pii/S0269749120361601.