title: Linking Intertidal and Subtidal Food Webs: Consumer-Mediated Transport of Intertidal Benthic Microalgal Carbon.
abstract: We examined stable carbon and nitrogen isotope ratios for a large variety of consumers in intertidal and subtidal habitats, and their potential primary food sources [i.e., microphytobenthos (MPB), phytoplankton, and Phragmites australis] in a coastal bay system, Yeoja Bay of Korea, to test the hypothesis that the transfer of intertidal MPB-derived organic carbon to the subtidal food web can be mediated by motile consumers. Compared to a narrow δ13C range (-18 to -16‰) of offshore consumers, a broad δ13C range (-18 to -12‰) of both intertidal and subtidal consumers indicated that 13C-enriched sources of organic matter are an important trophic source to coastal consumers. In the intertidal areas, δ13C of most consumers overlapped with or was 13C-enriched relative to MPB. Despite the scarcity of MPB in the subtidal, highly motile consumers in subtidal habitat had nearly identical δ13C range with many intertidal foragers (including crustaceans and fish), overlapping with the range of MPB. In contrast, δ13C values of many sedentary benthic invertebrates in the subtidal areas were similar to those of offshore consumers and more 13C-depleted than motile foragers, indicating high dependence on phytoplankton-derived carbon. The isotopic mixing model calculation confirms that the majority of motile consumers and also some of subtidal sedentary ones depend on intertidal MPB for more than a half of their tissue carbon. Finally, although further quantitative estimates are needed, these results suggest that direct foraging by motile consumers on intertidal areas, and thereby biological transport of MPB-derived organic carbon to the subtidal areas, may provide important trophic connection between intertidal production and the nearshore shallow subtidal food webs.
authors.affiliation: School of Environmental Science & Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
authors.forename: Chang-Keun
authors.initials: CK
authors.lastname: Kang
authors.affiliation: Department of Marine Bioscience, Gangneung-Wonju Nattional University, Gangneung, Republic of Korea.
authors.forename: Hyun Je
authors.initials: HJ
authors.lastname: Park
authors.affiliation: Korea Polar Research Institute, Korea Institute of Ocean Science and Technology, Incheon, Republic of Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Choy
authors.affiliation: Faculty of Marine Biomedical Science, Jeju National University, Jeju, Republic of Korea.
authors.forename: Kwang-Sik
authors.initials: KS
authors.lastname: Choi
authors.affiliation: Fisheries Resources Management Division, National Fisheries Research & Development Institute (NFRDI), Busan, Republic of Korea.
authors.forename: Kangseok
authors.initials: K
authors.lastname: Hwang
authors.affiliation: Subtropical Fisheries Research Center, NFRDI, Jeju, Republic of Korea.
authors.forename: Jong-Bin
authors.initials: JB
authors.lastname: Kim
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D002244:Carbon / Q000737:chemistry* / Q000378:metabolism; D002247:Carbon Isotopes / Q000737:chemistry / Q000378:metabolism; D049896:Crassostrea / Q000737:chemistry / Q000378:metabolism; D017753:Ecosystem; D020387:Food Chain; D058086:Microalgae / Q000737:chemistry* / Q000378:metabolism; D009587:Nitrogen Isotopes / Q000737:chemistry / Q000378:metabolism; D010839:Phytoplankton / Q000737:chemistry / Q000378:metabolism; D049894:Scapharca / Q000737:chemistry / Q000378:metabolism; D012621:Seasons; D015048:Zooplankton / Q000737:chemistry / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D002244:Carbon