Linkages between seagrass tissue O2 dynamics and ecosystem oxidation and feedbacks revealed using microsensors in situ
Research output: Contribution to conference › Conference abstract for conference › Research
Standard
Linkages between seagrass tissue O2 dynamics and ecosystem oxidation and feedbacks revealed using microsensors in situ. / Koch, Marguerite; Johnson, Christopher; MacLeod, Kasey; Travis, Levi; Madden, Chris; Pedersen, Ole.
2022. 22 Abstract from World Seagrass Conference & International Seagrass Biology Workshop, Annapolis, Massachusetts, United States.Research output: Contribution to conference › Conference abstract for conference › Research
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - ABST
T1 - Linkages between seagrass tissue O2 dynamics and ecosystem oxidation and feedbacks revealed using microsensors in situ
AU - Koch, Marguerite
AU - Johnson, Christopher
AU - MacLeod, Kasey
AU - Travis, Levi
AU - Madden, Chris
AU - Pedersen, Ole
PY - 2022
Y1 - 2022
N2 - Water column hypoxia, low tissue pO2 and H2S intrusion, a known phytotoxin, are linked to global seagrass decline. While many lab experiments have examined these relationships, only field studies capture the complexity of gas dynamics in situ. We examined internal pO2 and H2S dynamics in a dominant tropical seagrass Thalassia testudinum using microsensors. Based on 12 field deployments (48–72-h) across seasons, we show that T. testudinum has a high capacity for daytime leaf oxidation (42–53 kPa) that sustains oxic conditions in its tissues and supersaturates the water column with O2 (>21 kPa). While internal daytime O2 is consumed near sunset, positive feedback between seagrass O2 production and the supersaturated water column going into the night contributes to buffering of internal plant hypoxia at the beginning of the night. Leaf meristems went anoxic/hypoxic (0.6 kPa) at night even with high daytime irradiance, indicating a high ecosystem O2 consumption, and reliance on water column pO2 (19 kPa) through leaf pO2 (9 kPa) to prevent H2S from entering the meristem at night. Newly recruiting shoots into bare sediment also had the ability to minimize H2S intrusion. At ambient irradiance, we only detected H2S in the meristem when water column pO2 was hypoxic (<2 kPa) coincident with maximum water column temperatures (33 oC), an occurrence likely to increase with global warming. These data reinforce the importance of water quality management to sustain seagrass-dominated systems, particularly in nutrient-enriched estuaries and coastal lagoons.
AB - Water column hypoxia, low tissue pO2 and H2S intrusion, a known phytotoxin, are linked to global seagrass decline. While many lab experiments have examined these relationships, only field studies capture the complexity of gas dynamics in situ. We examined internal pO2 and H2S dynamics in a dominant tropical seagrass Thalassia testudinum using microsensors. Based on 12 field deployments (48–72-h) across seasons, we show that T. testudinum has a high capacity for daytime leaf oxidation (42–53 kPa) that sustains oxic conditions in its tissues and supersaturates the water column with O2 (>21 kPa). While internal daytime O2 is consumed near sunset, positive feedback between seagrass O2 production and the supersaturated water column going into the night contributes to buffering of internal plant hypoxia at the beginning of the night. Leaf meristems went anoxic/hypoxic (0.6 kPa) at night even with high daytime irradiance, indicating a high ecosystem O2 consumption, and reliance on water column pO2 (19 kPa) through leaf pO2 (9 kPa) to prevent H2S from entering the meristem at night. Newly recruiting shoots into bare sediment also had the ability to minimize H2S intrusion. At ambient irradiance, we only detected H2S in the meristem when water column pO2 was hypoxic (<2 kPa) coincident with maximum water column temperatures (33 oC), an occurrence likely to increase with global warming. These data reinforce the importance of water quality management to sustain seagrass-dominated systems, particularly in nutrient-enriched estuaries and coastal lagoons.
M3 - Conference abstract for conference
SP - 22
T2 - World Seagrass Conference & International Seagrass Biology Workshop
Y2 - 7 August 2022 through 12 August 2022
ER -
ID: 315754666