Sediment tolerance mechanisms identified in sponges using advanced imaging techniques

PeerJ

article

Brian W. Strehlow¹  Mari-Carmen Pineda⁴  Alan Duckworth⁴  Gary A. Kendrick¹  Michael Renton¹  Muhammad Azmi Abdul Wahab⁴  Nicole S. Webster⁴  Peta L. Clode¹ 

[1] School of Biological Sciences, University of Western Australia;Centre for Microscopy, Characterisation and Analysis, University of Western Australia;Oceans Institute, University of Western Australia;Australian Institute of Marine Science;Western Australian Marine Science Institution;School of Agriculture and Environment, University of Western Australia;Australian Centre for Ecogenomics, University of Queensland

关键词: Sponge;    Sediments;    3D X-ray microscopy;    Scanning electron microscopy;   

DOI  :  10.7717/peerj.3904

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Terrestrial runoff, resuspension events and dredging can affect filter-feeding sponges by elevating the concentration of suspended sediments, reducing light intensity, and smothering sponges with sediments. To investigate how sponges respond to pressures associated with increased sediment loads, the abundant and widely distributed Indo-Pacific species Ianthella basta was exposed to elevated suspended sediment concentrations, sediment deposition, and light attenuation for 48 h (acute exposure) and 4 weeks (chronic exposure). In order to visualise the response mechanisms, sponge tissue was examined by 3D X-ray microscopy and scanning electron microscopy (SEM). Acute exposures resulted in sediment rapidly accumulating in the aquiferous system of I. basta2 weeks) following chronic exposures, and I. basta also exhibited tissue regression and a smaller aquiferous system. The application of advanced imaging approaches revealed that I. basta employs a multilevel system for sediment rejection and elimination, containing both active and passive components. Sponges responded to sediment stress through (i) mucus production, (ii) exclusion of particles by incurrent pores, (iii) closure of oscula and pumping cessation, (iv) expulsion of particles from the aquiferous system, and (v) tissue regression to reduce the volume of the aquiferous system, thereby entering a dormant state. These mechanisms would result in tolerance and resilience to exposure to variable and high sediment loads associated with both anthropogenic impacts like dredging programs and natural pressures like flood events.

【 授权许可】

CC BY