Toomey et al. reply

Toomey, D. R.; Jousselin, David; Dunn, R. A.; Wilcock, William S. D.; Detrick, R. S.

doi:10.1038/nature07888

Cited by 4 publications

(5 citation statements)

References 9 publications

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“…While this interpretation has been controversial [ Singh and Macdonald , 2009; Toomey et al , 2009], the near alignment of the skew of the compressional focal mechanisms (∼15° anticlockwise) with the skew inferred in the mantle is notable, and also consistent with Nuvel 1‐A plate spreading direction for the area [ Gripp and Gordon , 2002]. Toomey et al [2009] suggest that the skew is a driving force for changes in plate boundary kinematics, with basal tractions imposed by mantle flow contributing to ongoing anticlockwise changes in plate spreading directions. While the skew in orientation of our C2 and C3 focal mechanisms are not well constrained, the results observed, if sustained through later deployments, would be consistent with Toomey et al's model, despite the general assumption that melt lens dynamics are decoupled from mantle melt supply [ Combier et al , 2008].…”

Section: Discussionmentioning

confidence: 90%

“…Recent results from analysis of active source seismics in the 9°–10° N EPR area have inferred an anticlockwise skew of ∼10° in the alignment of mantle upwelling from the normal of the ridge axis [ Toomey et al , 2007]. While this interpretation has been controversial [ Singh and Macdonald , 2009; Toomey et al , 2009], the near alignment of the skew of the compressional focal mechanisms (∼15° anticlockwise) with the skew inferred in the mantle is notable, and also consistent with Nuvel 1‐A plate spreading direction for the area [ Gripp and Gordon , 2002]. Toomey et al [2009] suggest that the skew is a driving force for changes in plate boundary kinematics, with basal tractions imposed by mantle flow contributing to ongoing anticlockwise changes in plate spreading directions.…”

Section: Discussionmentioning

confidence: 99%

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Seismogenic structure and processes associated with magma inflation and hydrothermal circulation beneath the East Pacific Rise at 9°50′N

Waldhauser

Tolstoy

2011

Geochem. Geophys. Geosyst.

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[1] A dense ocean bottom seismometer array recorded more than 7,300 microearthquakes between October 2003 and April 2004 on the fast spreading East Pacific Rise at 9°50′ N. A previous initial analysis of these data revealed the general structure of an along-axis oriented hydrothermal circulation cell, with an inferred down-flow zone near a 4th-order axial discontinuity, a horizontal band of seismicity overlying the axial magma chamber (AMC), and an upflow zone that correlates with activity patterns of hydrothermal vents. Here we present cross-correlation-based double-difference hypocenter locations that reveal further insight into the detailed structure and kinematics that control seismic failure. We find that the majority of events within the inferred down flow pipe occur near the surface where the entrenched seawater presumably lowers the frictional strength of faults generated by local tectonic stresses. Beneath the eastern side of the ridge axis, just above the AMC at ∼1.4 km depth, we observe repeated shear failure along well defined steeply east dipping faults. Composite focal mechanisms indicate reverse motion, suggesting that slip on these faults is caused by AMC inflation and possibly injection of magma into a narrow sill. We resolve a small counterclockwise skew in the strike of the reverse faults relative to the direction of the ridge axis, consistent with Nuvel 1A spreading direction suggesting that the regional tectonic stress field may be controlling the seismogenic structures at depth. Earthquakes on the reverse faults occur preferentially during peak extensional tidal stresses, indicating that these faults are critically stressed.

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Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Seismogenic structure and processes associated with magma inflation and hydrothermal circulation beneath the East Pacific Rise at 9°50′N

Waldhauser

Tolstoy

2011

Geochem. Geophys. Geosyst.

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“…Although RALF4 WT fully restored the fertility and pollen tube growth of the amiralf4/19 line, RALF4 R89E.R90E.R91E and RALF4 neutral surface conferred a moderate or severe reduction in vivo, respectively (Fig. 3, E to H) but nevertheless maintained their capacity to direct their growth toward the ovules (31). The growth defect of amiralf4/19 pollen tubes reflected a higher (not lower) growth velocity and premature bursting rate.…”

Section: Cell Wall Patterning and Integrity Through Lrx8-ralf4-pectin...mentioning

confidence: 93%

Plant cell wall patterning and expansion mediated by protein-peptide-polysaccharide interaction

Moussu,

Lee,

Haas

et al. 2023

Science

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Assembly of cell wall polysaccharides into specific patterns is required for plant growth. A complex of RAPID ALKALINIZATION FACTOR 4 (RALF4) and its cell wall–anchored LEUCINE-RICH REPEAT EXTENSIN 8 (LRX8)–interacting protein is crucial for cell wall integrity during pollen tube growth, but its molecular connection with the cell wall is unknown. Here, we show that LRX8-RALF4 complexes adopt a heterotetrametric configuration in vivo, displaying a dendritic distribution. The LRX8-RALF4 complex specifically interacts with demethylesterified pectins in a charge-dependent manner through RALF4’s polycationic surface. The LRX8-RALF4-pectin interaction exerts a condensing effect, patterning the cell wall’s polymers into a reticulated network essential for wall integrity and expansion. Our work uncovers a dual structural and signaling role for RALF4 in pollen tube growth and in the assembly of complex extracellular polymers.

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“…The hydrothermally active Endeavour Segment, located on the northern part of the intermediate-spreading Juan de Fuca Ridge, is 10 km long, with a 1 km wide axial valley that has rift walls reaching 200 m. Endeavour Segment hosts five major hydrothermal vent fields (Kelley et al, 2012;Kelley et al, 2014) that are underlain by magma lenses at depths of ~2-3 km (e.g., Van Ark et al, 2007) with microseismic activity linked to hydrothermal circulation between the magma lens and the seafloor (e.g., Toomey et al, 2009;Hooft et al, 2010). The Endeavour Hydrothermal Vents (EHV) became Canada's first MPA, following an act of parliament in 2003.…”

Section: Onc-endeavourmentioning

confidence: 99%

Integrating Multidisciplinary Observations in Vent Environments (IMOVE): Decadal Progress in Deep-Sea Observatories at Hydrothermal Vents

et al. 2022

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The unique ecosystems and biodiversity associated with mid-ocean ridge (MOR) hydrothermal vent systems contrast sharply with surrounding deep-sea habitats, however both may be increasingly threatened by anthropogenic activity (e.g., mining activities at massive sulphide deposits). Climate change can alter the deep-sea through increased bottom temperatures, loss of oxygen, and modifications to deep water circulation. Despite the potential of these profound impacts, the mechanisms enabling these systems and their ecosystems to persist, function and respond to oceanic, crustal, and anthropogenic forces remain poorly understood. This is due primarily to technological challenges and difficulties in accessing, observing and monitoring the deep-sea. In this context, the development of deep-sea observatories in the 2000s focused on understanding the coupling between sub-surface flow and oceanic and crustal conditions, and how they influence biological processes. Deep-sea observatories provide long-term, multidisciplinary time-series data comprising repeated observations and sampling at temporal resolutions from seconds to decades, through a combination of cabled, wireless, remotely controlled, and autonomous measurement systems. The three existing vent observatories are located on the Juan de Fuca and Mid-Atlantic Ridges (Ocean Observing Initiative, Ocean Networks Canada and the European Multidisciplinary Seafloor and water column Observatory). These observatories promote stewardship by defining effective environmental monitoring including characterizing biological and environmental baseline states, discriminating changes from natural variations versus those from anthropogenic activities, and assessing degradation, resilience and recovery after disturbance. This highlights the potential of observatories as valuable tools for environmental impact assessment (EIA) in the context of climate change and other anthropogenic activities, primarily ocean mining. This paper provides a synthesis on scientific advancements enabled by the three observatories this last decade, and recommendations to support future studies through international collaboration and coordination. The proposed recommendations include: i) establishing common global scientific questions and identification of Essential Ocean Variables (EOVs) specific to MORs, ii) guidance towards the effective use of observatories to support and inform policies that can impact society, iii) strategies for observatory infrastructure development that will help standardize sensors, data formats and capabilities, and iv) future technology needs and common sampling approaches to answer today’s most urgent and timely questions.

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Toomey et al. reply

Cited by 4 publications

References 9 publications

Seismogenic structure and processes associated with magma inflation and hydrothermal circulation beneath the East Pacific Rise at 9°50′N

Seismogenic structure and processes associated with magma inflation and hydrothermal circulation beneath the East Pacific Rise at 9°50′N

Plant cell wall patterning and expansion mediated by protein-peptide-polysaccharide interaction

Integrating Multidisciplinary Observations in Vent Environments (IMOVE): Decadal Progress in Deep-Sea Observatories at Hydrothermal Vents

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