title: Seeing the unseen--bioturbation in 4D: tracing bioirrigation in marine sediment using positron emission tomography and computed tomography.
abstract: Understanding spatial and temporal patterns of bioirrigation induced by benthic fauna ventilation is critical given its significance on benthic nutrient exchange and biogeochemistry in coastal ecosystems. The quantification of this process challenges marine scientists because faunal activities and behaviors are concealed in an opaque sediment matrix. Here, we use a hybrid medical imaging technique, positron emission tomography and computed tomography (PET/CT) to provide a qualitative visual and fully quantitative description of bioirrigation in 4D (space and time). As a study case, we present images of porewater advection induced by the well-studied lugworm (Arenicola marina). Our results show that PET/CT allows more comprehensive studies on ventilation and bioirrigation than possible using techniques traditionally applied in marine ecology. We provide a dynamic three-dimensional description of bioirrigation by the lugworm at very high temporal and spatial resolution. Results obtained with the PET/CT are in agreement with literature data on lugworm ventilation and bioirrigation. Major advantages of PET/CT over methods commonly used are its non-invasive and non-destructive approach and its capacity to provide information that otherwise would require multiple methods. Furthermore, PET/CT scan is versatile as it can be used for a variety of benthic macrofauna species and sediment types and it provides information on burrow morphology or animal behavior. The lack of accessibility to the expensive equipment is its major drawback which can only be overcome through collaboration among several institutions.
authors.affiliation: Department of Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Delefosse
authors.affiliation: Department of Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Erik
authors.initials: E
authors.lastname: Kristensen
authors.affiliation: Department of Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Diane
authors.initials: D
authors.lastname: Crunelle
authors.affiliation: Department of Nuclear medicine, Odense University Hospital, Odense, Denmark; Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Poul Erik
authors.initials: PE
authors.lastname: Braad
authors.affiliation: Department of Nuclear medicine, Odense University Hospital, Odense, Denmark; Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Johan Hygum
authors.initials: JH
authors.lastname: Dam
authors.affiliation: Department of Nuclear medicine, Odense University Hospital, Odense, Denmark; Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Helge
authors.initials: H
authors.lastname: Thisgaard
authors.affiliation: Department of Nuclear medicine, Odense University Hospital, Odense, Denmark; Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Thomassen
authors.affiliation: Department of Nuclear medicine, Odense University Hospital, Odense, Denmark; Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Poul Flemming
authors.initials: PF
authors.lastname: Høilund-Carlsen
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D017753:Ecosystem; D005247:Feeding Behavior; D019015:Geologic Sediments; D060587:Groundwater; D021621:Imaging, Three-Dimensional / Q000379:methods; D008386:Marine Biology / Q000379:methods; D011077:Polychaeta / Q000502:physiology*; D049268:Positron-Emission Tomography / Q000379:methods; D012119:Respiration; D014057:Tomography, X-Ray Computed / Q000379:methods
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