Hannah Jacob, K. Springer, Laura Belter, A. Kunzmann
{"title":"Symbiodiniaceae in and ex hospite have differential physiological responses under different heat stress scenarios","authors":"Hannah Jacob, K. Springer, Laura Belter, A. Kunzmann","doi":"10.1080/17451000.2023.2198240","DOIUrl":null,"url":null,"abstract":"ABSTRACT Extreme seawater temperatures are linked to increasingly frequent cnidarian bleaching, a breakdown of the symbiosis between host and endosymbiotic dinoflagellates. This can be driven by several anthropogenic stressors, of which seawater warming is a major and frequent one. It remains unclear whether this is caused by intrinsic properties of the host or exclusively by the symbiont. This study investigates the response to elevated temperatures of dinoflagellate symbionts in and ex hospite, particularly to find out whether thermal tolerance differs between endosymbionts and free-living micro-algae. Maximum quantum yield of photosystem II (Fv/Fm ) and symbiont cell density were measured in seven different cnidarian species and five cultures of isolated endosymbionts subjected to temperatures of 26°C (control), 30°C and 34°C for 21 days. Isolated dinoflagellate cells showed a susceptibility to elevated temperatures of 30°C, evidenced by a decrease in photochemical efficiency and cell density of the cultures, as well as a progressive disintegration of cellular structures and loss of pigmentation of all but two cultures during the first week of exposure. Bleaching of coral holobionts at 30°C could be explained by reduced density of algae cells in host tissue. This effect was particularly evident in soft corals. Exposure to 34°C resulted in drastic bleaching of stony coral species, anemones and jellyfish, and even the death of soft corals. Data from this study show different responses to elevated thermal conditions across several species and different genera of symbionts and emphasize the important role of dinoflagellate symbionts in the holobiont response to elevated seawater temperatures.","PeriodicalId":18195,"journal":{"name":"Marine Biology Research","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Marine Biology Research","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1080/17451000.2023.2198240","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
ABSTRACT Extreme seawater temperatures are linked to increasingly frequent cnidarian bleaching, a breakdown of the symbiosis between host and endosymbiotic dinoflagellates. This can be driven by several anthropogenic stressors, of which seawater warming is a major and frequent one. It remains unclear whether this is caused by intrinsic properties of the host or exclusively by the symbiont. This study investigates the response to elevated temperatures of dinoflagellate symbionts in and ex hospite, particularly to find out whether thermal tolerance differs between endosymbionts and free-living micro-algae. Maximum quantum yield of photosystem II (Fv/Fm ) and symbiont cell density were measured in seven different cnidarian species and five cultures of isolated endosymbionts subjected to temperatures of 26°C (control), 30°C and 34°C for 21 days. Isolated dinoflagellate cells showed a susceptibility to elevated temperatures of 30°C, evidenced by a decrease in photochemical efficiency and cell density of the cultures, as well as a progressive disintegration of cellular structures and loss of pigmentation of all but two cultures during the first week of exposure. Bleaching of coral holobionts at 30°C could be explained by reduced density of algae cells in host tissue. This effect was particularly evident in soft corals. Exposure to 34°C resulted in drastic bleaching of stony coral species, anemones and jellyfish, and even the death of soft corals. Data from this study show different responses to elevated thermal conditions across several species and different genera of symbionts and emphasize the important role of dinoflagellate symbionts in the holobiont response to elevated seawater temperatures.
期刊介绍:
Marine Biology Research (MBRJ) provides a worldwide forum for key information, ideas and discussion on all areas of marine biology and biological oceanography. Founded in 2005 as a merger of two Scandinavian journals, Sarsia and Ophelia, MBRJ is based today at the Institute of Marine Research, Bergen, Norway. The Journal’s scope encompasses basic and applied research from all oceans and marine habitats and on all marine organisms, the main criterium for acceptance being quality.