Irradiance, Water Column O2, and Tide Drive Internal O2 Dynamics and Meristem H2S Detection in the Dominant Caribbean-Tropical Atlantic Seagrass, Thalassia testudinum

Koch, Marguerite S.; Johnson, Craig R.; Madden, C.J.; Pedersen, Ole

doi:10.1007/s12237-022-01064-y

Cited by 8 publications

(7 citation statements)

References 61 publications

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“…The essential requirement of seagrass for soft substrate is self-evident, but our model showed the probability of eelgrass occurrence was also lower on fine-grain muddy substrates compared to more sandy sediments. Fine grain sediments are often enriched in organic matter content (Fonseca and Bell, 1998;Wicks et al, 2009;Krause-Jensen et al, 2011) with concomitant increases in hydrogen sulfide (Peŕez et al, 2007;Krause-Jensen et al, 2011), a well-known phytotoxin to eelgrass and other SAV (Goodman et al, 1995;Koch, 2001;Peŕez et al, 2007) that becomes problematic under hypoxic conditions linked to environmental stress or poor water quality (Koch et al, 2022). Fine sediments high in organic content are more common in quiescent areas of lower current velocities and wave exposure (Fonseca and Bell, 1998;Koch, 2001;Krumhansl et al, 2021), but SAV is also subject to diffusive boundary layer constraints in areas of lower water motion (Koch, 2001).…”

Section: Discussionmentioning

confidence: 99%

Fine-scale ensemble species distribution modeling of eelgrass (Zostera marina) to inform nearshore conservation planning and habitat management

O’Brien

Wong²,

Stanley³

2022

Front. Mar. Sci.

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Baseline data on the distribution and extent of biogenic habitat-forming species at a high spatial resolution are essential to inform habitat management strategies, preserve ecosystem integrity, and achieve effective conservation objectives in the nearshore. Model-based approaches to map suitable habitat for these species are a key tool to address this need, filling in gaps where observations are otherwise unavailable and remote sensing methods are limited by turbid waters or cannot be applied at scale. We developed a high resolution (35 m) ensemble species distribution model to predict the distribution of eelgrass (Zostera marina) along the Atlantic coast of Nova Scotia, Canada where the observational coverage of eelgrass occurrence is sparse and nearshore waters are optically complex. Our ensemble model was derived as a performance-weighted average prediction of 7 different modeling methods fit to 6 physical predictors (substrate type, depth, wave exposure, slope, and two bathymetric position indices) and evaluated with a 5-fold spatially-blocked cross-validation procedure. The ensemble model showed moderate predictive performance (Area Under the Receiver-Operating Characteristic Curve (AUC) = 0.803 ± 0.061, True Skill Statistic (TSS) = 0.531 ± 0.100; mean ± SD), high sensitivity (92.0 ± 4.5), and offered some improvement over individual models. Substrate type, depth, and relative wave exposure were the most influential predictors associated with eelgrass occurrence, where the highest probabilities were associated with sandy and sandy-mud sediments, depths ranging 0 m – 4 m, and low to intermediate wave exposure. Within our study region, we predicted a total extent of suitable eelgrass habitat of 38,130 ha. We found suitable habitat was particularly extensive within the long narrow inlets and extensive shallow flats of the South Shore, Eastern Shore, and Bras d’Or Lakes. We also identified substantial overlap of eelgrass habitat with previously identified Ecologically and Biologically Significant Areas that guide regional conservation planning while also highlighting areas of greater prediction uncertainty arising from disagreement among modeling methods. By offering improved sensitivity and insights into the fine-scale regional distribution of a habitat-forming species with associated uncertainties, our ensemble-based modeling approach provides improved support to numerous nearshore applications including conservation planning and restoration, marine spatial and emergency response planning, environmental impact assessments, and fish habitat protection.

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Section: Discussionmentioning

confidence: 99%

Fine-scale ensemble species distribution modeling of eelgrass (Zostera marina) to inform nearshore conservation planning and habitat management

O’Brien

Wong²,

Stanley³

2022

Front. Mar. Sci.

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“…In contrast, in shoots with atmospheric contact, O 2 deriving from photosynthesis would be vented into the surrounding air. The importance of light on plant tissue O 2 in situ is nicely exemplified by diurnal leaf O 2 and irradiance measurements in seagrass (Thalassia testidinum) (Koch et al 2022a). Here, a decline in daytime irradiance of ~1000 μmol photons m −2 s −1 from passage of clouds resulted in a rapid decrease in leaf O 2 status from 45 to 27 kPa.…”

Section: O 2 Status In Submerged Plant Tissuesthe Importance Of Lightmentioning

confidence: 97%

“…Continuous O 2 measurements using microelectrodes have revealed severe hyperoxia of >40 kPa O 2 (Sand-Jensen et al 2005;Pedersen et al 2006Pedersen et al , 2016Rich et al 2013;Koch et al 2022a) in submerged wetland and aquatic plants. The highest non-manipulated plant tissue O 2 level reported in the literature (53.1 kPa) was measured in Thalassia hemprichii subjected to submergence by tidal waters and high radiation (2000 μmol photons m −2 s −1 ) (Pedersen et al 2016).…”

Section: O 2 Status In Submerged Plant Tissuesthe Importance Of Lightmentioning

confidence: 99%

“…Complete or even partial submergence affects plant O 2 status due to the 10 000-time slower gas diffusion in water than in air, lower solubility of O 2 in water than in air, light attenuation by flood waters and microorganisms depleting flooded soils of O 2 (Voesenek et al 2006). Studies have also demonstrated that biotic and abiotic factors such as pathogen infection, temperature, salinity, and light conditions affect plant tissue O 2 status (Kumari et al 2017;Chung et al 2019;Koch et al 2022aKoch et al , 2022b. Thus, the lack of an active O 2 distribution system in plants, presence of non-photosynthetic plant tissues, and a number of biotic and abiotic factors affecting tissue O 2 , thereby resulting in substantial internal gradients in molecular O 2 .…”

Section: Introductionmentioning

confidence: 99%

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A meta-analysis of plant tissue O2 dynamics

2023

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Adequate tissue O2 supply is crucial for plant function. We aimed to identify the environmental conditions and plant characteristics that affect plant tissue O2 status. We extracted data and performed meta-analysis on >1500 published tissue O2 measurements from 112 species. Tissue O2 status ranged from anoxic conditions in roots to >53 kPa in submerged, photosynthesising shoots. Using information-theoretic model selection, we identified ‘submergence’, ‘light’, ‘tissue type’ as well as ‘light × submergence’ interaction as significant drivers of tissue O2 status. Median O2 status were especially low (<50% of atmospheric equilibrium) in belowground rhizomes, potato (Solanum tuberosum) tubers and root nodules. Mean shoot and root O2 were ~25% higher in light than in dark when shoots had atmospheric contact. However, light showed a significant interaction with submergence on plant O2, with a submergence-induced 44% increase in light, compared with a 42% decline in dark, relative to plants with atmospheric contact. During submergence, ambient water column O2 and shoot tissue O2 correlated stronger in darkness than in light conditions. Although use of miniaturised Clark-type O2 electrodes has enhanced understanding of plant O2 dynamics, application of non-invasive methods in plants is still lacking behind its widespread use in mammalian tissues.

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“…In particular, studies of oxygen dynamics in oxygen diffusion pathways under waterlogging conditions are limited, and tissue oxygen concentration profiles remain at the forefront. Concerning the significant contribution of the above-ground parts as an oxygen source, photosynthetically derived oxygen accumulates in the above-ground portions of submerged plants and serves as an oxygen source to the roots [ 16 , 17 , 18 ]. However, it remains unknown whether the oxygen transport properties of the leaves and stems contribute to interspecific differences in oxygen concentrations in waterlogged plants in which the above-ground parts are exposed to an atmosphere with a lower gas diffusion resistance than water.…”

Section: Introductionmentioning

confidence: 99%

Spatial O2 Profile in Coix lacryma-jobi and Sorghum bicolor along the Gas Diffusion Pathway under Waterlogging Conditions

Tamaru,

Goto,

Sakagami

2023

Plants

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While internal aeration in plants is critical for adaptation to waterlogging, there is a gap in understanding the differences in oxygen diffusion gradients from shoots to roots between hypoxia-tolerant and -sensitive species. This study aims to elucidate the differences in tissue oxygen concentration at various locations on the shoot and root between a hypoxia-tolerant species and a -sensitive species using a microneedle sensor that allows for spatial oxygen profiling. Job’s tears, a hypoxia-tolerant species, and sorghum, a hypoxia-susceptible species, were tested. Plants aged 10 days were acclimated to a hypoxic agar solution for 12 days. Oxygen was profiled near the root tip, root base, root shoot junction, stem, and leaf. An anatomical analysis was also performed on the roots used for the O2 profile. The oxygen partial pressure (pO2) values at the root base and tip of sorghum were significantly lower than that of the root of Job’s tears. At the base of the root of Job’s tears, pO2 rapidly decreased from the root cortex to the surface, indicating a function to inhibit oxygen leakage. No significant differences in pO2 between the species were identified in the shoot part. The root cortex to stele ratio was significantly higher from the root tip to the base in Job’s tears compared to sorghum. The pO2 gradient began to differ greatly at the root shoot junction and root base longitudinally, and between the cortex and stele radially, between Job’s tears and sorghum. Differences in the root oxygen retention capacity and the cortex to stele ratio are considered to be related to differences in pO2.

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Irradiance, Water Column O2, and Tide Drive Internal O2 Dynamics and Meristem H2S Detection in the Dominant Caribbean-Tropical Atlantic Seagrass, Thalassia testudinum

Cited by 8 publications

References 61 publications

Fine-scale ensemble species distribution modeling of eelgrass (Zostera marina) to inform nearshore conservation planning and habitat management

Fine-scale ensemble species distribution modeling of eelgrass (Zostera marina) to inform nearshore conservation planning and habitat management

A meta-analysis of plant tissue O2 dynamics

Spatial O2 Profile in Coix lacryma-jobi and Sorghum bicolor along the Gas Diffusion Pathway under Waterlogging Conditions

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