Ciliary flows in corals ventilate target areas of high photosynthetic oxygen production
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Ciliary flows in corals ventilate target areas of high photosynthetic oxygen production. / Pacherres, Cesar O.; Ahmerkamp, Soeren; Koren, Klaus; Richter, Claudio; Holtappels, Moritz.
I: Current Biology, Bind 32, Nr. 19, 2022, s. 4150-4158.e3.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Ciliary flows in corals ventilate target areas of high photosynthetic oxygen production
AU - Pacherres, Cesar O.
AU - Ahmerkamp, Soeren
AU - Koren, Klaus
AU - Richter, Claudio
AU - Holtappels, Moritz
N1 - Publisher Copyright: © 2022 The Author(s)
PY - 2022
Y1 - 2022
N2 - Most tropical corals live in symbiosis with Symbiodiniaceae algae whose photosynthetic production of oxygen (O2) may lead to excess O2 in the diffusive boundary layer (DBL) above the coral surface. When flow is low, cilia-induced mixing of the coral DBL is vital to remove excess O2 and prevent oxidative stress that may lead to coral bleaching and mortality. Here, we combined particle image velocimetry using O2-sensitive nanoparticles (sensPIV) with chlorophyll (Chla)-sensitive hyperspectral imaging to visualize the microscale distribution and dynamics of ciliary flows and O2 in the coral DBL in relation to the distribution of Symbiodiniaceae Chla in the tissue of the reef building coral, Porites lutea. Curiously, we found an inverse relation between O2 in the DBL and Chla in the underlying tissue, with patches of high O2 in the DBL above low Chla in the underlying tissue surrounding the polyp mouth areas and pockets of low O2 concentrations in the DBL above high Chla in the coenosarc tissue connecting neighboring polyps. The spatial segregation of Chla and O2 is related to ciliary-induced flows, causing a lateral redistribution of O2 in the DBL. In a 2D transport-reaction model of the coral DBL, we show that the enhanced O2 transport allocates parts of the O2 surplus to areas containing less chla, which minimizes oxidative stress. Cilary flows thus confer a spatially complex mass transfer in the coral DBL, which may play an important role in mitigating oxidative stress and bleaching in corals.
AB - Most tropical corals live in symbiosis with Symbiodiniaceae algae whose photosynthetic production of oxygen (O2) may lead to excess O2 in the diffusive boundary layer (DBL) above the coral surface. When flow is low, cilia-induced mixing of the coral DBL is vital to remove excess O2 and prevent oxidative stress that may lead to coral bleaching and mortality. Here, we combined particle image velocimetry using O2-sensitive nanoparticles (sensPIV) with chlorophyll (Chla)-sensitive hyperspectral imaging to visualize the microscale distribution and dynamics of ciliary flows and O2 in the coral DBL in relation to the distribution of Symbiodiniaceae Chla in the tissue of the reef building coral, Porites lutea. Curiously, we found an inverse relation between O2 in the DBL and Chla in the underlying tissue, with patches of high O2 in the DBL above low Chla in the underlying tissue surrounding the polyp mouth areas and pockets of low O2 concentrations in the DBL above high Chla in the coenosarc tissue connecting neighboring polyps. The spatial segregation of Chla and O2 is related to ciliary-induced flows, causing a lateral redistribution of O2 in the DBL. In a 2D transport-reaction model of the coral DBL, we show that the enhanced O2 transport allocates parts of the O2 surplus to areas containing less chla, which minimizes oxidative stress. Cilary flows thus confer a spatially complex mass transfer in the coral DBL, which may play an important role in mitigating oxidative stress and bleaching in corals.
KW - boundary layer
KW - chlorophyll
KW - cilia
KW - flow dynamics
KW - oxygen flux
KW - Symbiodinium
U2 - 10.1016/j.cub.2022.07.071
DO - 10.1016/j.cub.2022.07.071
M3 - Journal article
C2 - 36002003
AN - SCOPUS:85139313658
VL - 32
SP - 4150-4158.e3
JO - Current Biology
JF - Current Biology
SN - 0960-9822
IS - 19
ER -
ID: 332621628