Heat stress of two tropical seagrass species during low tides: impact on underwater net photosynthesis, dark respiration and diel in situ internal aeration
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Heat stress of two tropical seagrass species during low tides : impact on underwater net photosynthesis, dark respiration and diel in situ internal aeration. / Pedersen, Ole; Colmer, Timothy D.; Borum, Jens; Zavala-Perez, Andrea; Kendrick, Gary A.
I: New Phytologist, Bind 210, Nr. 4, 2016, s. 1207-1218.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Heat stress of two tropical seagrass species during low tides
T2 - impact on underwater net photosynthesis, dark respiration and diel in situ internal aeration
AU - Pedersen, Ole
AU - Colmer, Timothy D.
AU - Borum, Jens
AU - Zavala-Perez, Andrea
AU - Kendrick, Gary A.
PY - 2016
Y1 - 2016
N2 - Seagrasses grow submerged in aerated seawater but often in low O2 sediments. Elevated temperatures and low O2 are stress factors. Internal aeration was measured in two tropical seagrasses, Thalassia hemprichii and Enhalus acoroides, growing with extreme tides and diel temperature amplitudes. Temperature effects on net photosynthesis (PN) and dark respiration (RD) of leaves were evaluated. Daytime low tide was characterized by high pO2 (54 kPa), pH (8.8) and temperature (38°C) in shallow pools. As PN was maximum at 33°C (9.1 and 7.2 μmol O2 m-2 s-1 in T. hemprichii and E. acoroides, respectively), the high temperatures and reduced CO2 would have diminished PN, whereas RD increased (Q10 of 2.0-2.7) above that at 33°C (0.45 and 0.33 μmol O2 m-2 s-1, respectively). During night-time low tides, O2 declined resulting in shoot base anoxia in both species, but incoming water containing c. 20 kPa O2 relieved the anoxia. Shoots exposed to 40°C for 4 h showed recovery of PN and RD, whereas 45°C resulted in leaf damage. These seagrasses are 'living near the edge', tolerant of current diel O2 and temperature extremes, but if temperatures rise both species may be threatened in this habitat.
AB - Seagrasses grow submerged in aerated seawater but often in low O2 sediments. Elevated temperatures and low O2 are stress factors. Internal aeration was measured in two tropical seagrasses, Thalassia hemprichii and Enhalus acoroides, growing with extreme tides and diel temperature amplitudes. Temperature effects on net photosynthesis (PN) and dark respiration (RD) of leaves were evaluated. Daytime low tide was characterized by high pO2 (54 kPa), pH (8.8) and temperature (38°C) in shallow pools. As PN was maximum at 33°C (9.1 and 7.2 μmol O2 m-2 s-1 in T. hemprichii and E. acoroides, respectively), the high temperatures and reduced CO2 would have diminished PN, whereas RD increased (Q10 of 2.0-2.7) above that at 33°C (0.45 and 0.33 μmol O2 m-2 s-1, respectively). During night-time low tides, O2 declined resulting in shoot base anoxia in both species, but incoming water containing c. 20 kPa O2 relieved the anoxia. Shoots exposed to 40°C for 4 h showed recovery of PN and RD, whereas 45°C resulted in leaf damage. These seagrasses are 'living near the edge', tolerant of current diel O2 and temperature extremes, but if temperatures rise both species may be threatened in this habitat.
KW - Enhalus acoroides
KW - Thalassia hemprichii
KW - Anaerobiosis
KW - Anoxia
KW - Submerged plants
KW - Temperature stress
KW - Thermal stress
KW - Water column and tissue O
U2 - 10.1111/nph.13900
DO - 10.1111/nph.13900
M3 - Journal article
C2 - 26914396
AN - SCOPUS:84959420891
VL - 210
SP - 1207
EP - 1218
JO - New Phytologist
JF - New Phytologist
SN - 0028-646X
IS - 4
ER -
ID: 161240303