A global assessment of the chemical recalcitrance of seagrass tissues: Implications for long-term carbon sequestration

© 2017 Trevathan-Tackett, Macreadie, Sanderman, Baldock, Howes and Ralph. Seagrass ecosystems have recently been identified for their role in climate change mitigation due to their globally-significant carbon sinks; yet, the capacity of seagrasses to sequester carbon has been shown to vary greatly among seagrass ecosystems. The recalcitrant nature of seagrass tissues, or the resistance to degradation back into carbon dioxide, is one aspect thought to influence sediment carbon stocks. In this study, a global survey investigated how the macromolecular chemistry of seagrass leaves, sheaths/stems, rhizomes and roots varied across 23 species from 16 countries. The goal was to understand how this seagrass chemistry might influence the capacity of seagrasses to contribute to sediment carbon stocks. Three non-destructive analytical chemical analyses were used to investigate seagrass chemistry: thermogravimetric analysis (TGA) and solid state13 C-NMR and infrared spectroscopy. A strong latitudinal influence on carbon quality was found, whereby temperate seagrasses contained 5% relatively more labile carbon, and tropical seagrasses contained 3% relatively more refractory carbon. Sheath/stem tissues significantly varied across taxa, with larger morphologies typically containing more refractory carbon than smaller morphologies. Rhizomes were characterized by a higher proportion of labile carbon (16%of total organic matter compared to 8–10%in other tissues); however, high rhizome biomass production and slower remineralization in anoxic sediments will likely enhance these below-ground tissues’ contributions to long-termcarbon stocks. Our study provides a standardized and global dataset on seagrass carbon quality across tissue types, taxa and geography that can be incorporated in carbon sequestration and storage models as well as ecosystem valuation and management strategies

Development of peripheral vision tests for driver assessment

In the interests of identifying older drivers at higher risk of crashing, with a view to restricting their driving, fitness to drive tests require development and validation. One particular test that makes claim for inclusion in any battery of fitness to drive tests is the Useful Field of View test (UFOV)1. UFOV subtests appear to depend heavily on speed of visual processing, and on indexing crowding in peripheral vision. However, UFOV is a proprietary instrument and other custom software is available for measuring speed of visual processing and crowding in peripheral vision. Sixty participants aged over 60 completed UFOV. They also completed inspection time (IT), a measure of speed of visual processing, and crowding across the visual field (CAVF), a measure indexing effects of strength of crowding in peripheral vision. Thus, the current study compared performance on UFOV, inspection time (IT) and crowding across the visual field (CAVF). The main outcomes here were that the IT and CAVF measures had high test-retest reliability over a period of about one week and did not exhibit statistically significant practice effects. By way of contrast, although UFOV measures were also highly reliable, two of three UFOV measures, Divided Attention and Selective Attention, showed practice effects; the third measure, Processing Speed, showed severe range restriction in the current sample of healthy older adults. Correlations between CAVF, IT and UFOV Selective Attention were very high. These outcomes suggests that IT and CAVF together may well prove appropriate and useful as part of an assessment of fitness to drive. This suggestion needs to be validated by research investigating whether these tests predict crash risk in the same way that UFOV does.In the interests of identifying older drivers at higher risk of crashing, with a view to restricting their driving, fitness to drive tests require development and validation. One particular test that makes claim for inclusion in any battery of fitness to drive tests is the Useful Field of View test (UFOV)1. UFOV subtests appear to depend heavily on speed of visual processing, and on indexing crowding in peripheral vision. However, UFOV is a proprietary instrument and other custom software is available for measuring speed of visual processing and crowding in peripheral vision. Sixty participants aged over 60 completed UFOV. They also completed inspection time (IT), a measure of speed of visual processing, and crowding across the visual field (CAVF), a measure indexing effects of strength of crowding in peripheral vision. Thus, the current study compared performance on UFOV, inspection time (IT) and crowding across the visual field (CAVF). The main outcomes here were that the IT and CAVF measures had high test-retest reliability over a period of about one week and did not exhibit statistically significant practice effects. By way of contrast, although UFOV measures were also highly reliable, two of three UFOV measures, Divided Attention and Selective Attention, showed practice effects; the third measure, Processing Speed, showed severe range restriction in the current sample of healthy older adults. Correlations between CAVF, IT and UFOV Selective Attention were very high. These outcomes suggests that IT and CAVF together may well prove appropriate and useful as part of an assessment of fitness to drive. This suggestion needs to be validated by research investigating whether these tests predict crash risk in the same way that UFOV does.N.R. Burns, S.M. Kremer and M.R.J. Baldoc

Use of the behaviour change wheel to improve everyday person-centred conversations on physical activity across healthcare

Abstract: Background: An implementation gap exists between the evidence supporting physical activity in the prevention and management of long-term medical conditions and clinical practice. Person-centred conversations, i.e. focussing on the values, preferences and aspirations of each individual, are required from healthcare professionals. However, many currently lack the capability, opportunity, and motivation to have these conversations. This study uses the Behaviour Change Wheel (BCW) to inform the development of practical and educational resources to help bridge this gap. Methods: The BCW provides a theoretical approach to enable the systematic development of behaviour change interventions. Authors followed the described eight-step process, considered results from a scoping review, consulted clinical working groups, tested and developed ideas across clinical pathways, and agreed on solutions to each stage by consensus. Results: The behavioural diagnosis identified healthcare professionals’ initiation of person-centred conversations on physical activity at all appropriate opportunities in routine medical care as a suitable primary target for interventions. Six intervention functions and five policy categories met the APEASE criteria. We mapped 17 Behavioural Change Techniques onto BCW intervention functions to define intervention strategies. Conclusions: This study uses the BCW to outline a coherent approach for intervention development to improve healthcare professionals’ frequency and quality of conversations on physical activity across clinical practice. Time-sensitive and role-specific resources might help healthcare professionals understand the focus of their intervention. Educational resources aimed at healthcare professionals and patients could have mutual benefit, should fit into existing care pathways and support professional development. A trusted information source with single-point access via the internet is likely to improve accessibility. Future evaluation of resources built and coded using this framework is required to establish the effectiveness of this approach and help improve understanding of what works to change conversations around physical activity in clinical practice

A global assessment of the chemical recalcitrance of seagrass tissues: Implications for long-term carbon sequestration

Seagrass ecosystems have recently been identified for their role in climate change mitigation due to their globally-significant carbon sinks; yet, the capacity of seagrasses to sequester carbon has been shown to vary greatly among seagrass ecosystems. The recalcitrant nature of seagrass tissues, or the resistance to degradation back into carbon dioxide, is one aspect thought to influence sediment carbon stocks. In this study, a global survey investigated how the macromolecular chemistry of seagrass leaves, sheaths/stems, rhizomes and roots varied across 23 species from 16 countries. The goal was to understand how this seagrass chemistry might influence the capacity of seagrasses to contribute to sediment carbon stocks. Three non-destructive analytical chemical analyses were used to investigate seagrass chemistry: thermogravimetric analysis (TGA) and solid state 13 C-NMR and infrared spectroscopy. A strong latitudinal influence on carbon quality was found, whereby temperate seagrasses contained 5% relatively more labile carbon, and tropical seagrasses contained 3% relatively more refractory carbon. Sheath/stem tissues significantly varied across taxa, with larger morphologies typically containing more refractory carbon than smaller morphologies. Rhizomes were characterized by a higher proportion of labile carbon (16%of total organic matter compared to 8–10%in other tissues); however, high rhizome biomass production and slower remineralization in anoxic sediments will likely enhance these below-ground tissues’ contributions to long-termcarbon stocks. Our study provides a standardized and global dataset on seagrass carbon quality across tissue types, taxa and geography that can be incorporated in carbon sequestration and storage models as well as ecosystem valuation and management strategies

What do healthcare professionals want from a resource to support person-centred conversations on physical activity? A mixed-methods, user-centric approach to developing educational resources.

Objectives: Healthcare is a fundamental action area in population efforts to address the global disease burden from physical inactivity. However, healthcare professionals lack the knowledge, skills and confidence to have regular conversations about physical activity. This study aimed to: (1) understand the requirements of healthcare professionals and patients from a resource to support routine physical activity conversations in clinical consultations and (2) develop such a resource. Methods: This study used codesign principles across two phases, actively involving relevant stakeholders in an iterative development process. The preparatory phase included a scoping literature review and workshops with multidisciplinary healthcare professionals and patients. The Delphi phase included the development of a draft resource, a three-stage modified online Delphi study and an external review. Results: The scoping review highlighted the importance of addressing time restrictions, a behaviour change skill deficit, the need for resources to fit into existing systems and meeting patient expectations. Consultation included 69 participants across two clinical workshops. They recommended using the internet, valued guidance on all aspects of physical activity conversations and were concerned about how to use a person-centred approach. The Delphi phase, including 15 expert participants, met agreement criteria in two stages to develop the resource. Conclusion: This mixed-methods study delivered an online resource that was codesigned with and based on the requirements of healthcare professionals and patients. The resource presents condition-specific ‘1-minute’, ‘5-minute’ and ‘more minute’ person-centred and evidence-based conversation templates on physical activity in an accessible and usable format to meet the needs of real-life clinical practice

Sediment anoxia limits microbial-driven seagrass carbon remineralization under warming conditions

Seagrass ecosystems are significant carbon sinks, and their resident microbial communities ultimately determine the quantity and quality of carbon sequestered. However, environmental perturbations have been predicted to affect microbial-driven seagrass decomposition and subsequent carbon sequestration. Utilizing techniques including 16S-rDNA sequencing, solid-state NMR and microsensor profiling, we tested the hypothesis that elevated seawater temperatures and eutrophication enhance the microbial decomposition of seagrass leaf detritus and rhizome/root tissues. Nutrient additions had a negligible effect on seagrass decomposition, indicating an absence of nutrient limitation. Elevated temperatures caused a 19% higher biomass loss for aerobically decaying leaf detritus, coinciding with changes in bacterial community structure and enhanced lignocellulose degradation. Although, community shifts and lignocellulose degradation were also observed for rhizome/root decomposition, anaerobic decay was unaffected by temperature. These observations suggest that oxygen availability constrains the stimulatory effects of temperature increases on bacterial carbon remineralization, possibly through differential temperature effects on bacterial functional groups, including putative aerobic heterotrophs (e.g. Erythrobacteraceae, Hyphomicrobiaceae) and sulfate-reducers (e.g. Desulfobacteraceae). Consequently, under elevated seawater temperatures, carbon accumulation rates may diminish due to higher remineralization rates at the sediment surface. Nonetheless, the anoxic conditions ubiquitous to seagrass sediments can provide a degree of carbon protection under warming seawater temperatures

Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO2 emission benefits of VCE conservation and restoration. Australia contributes 5–11% of the C stored in VCE globally (70–185 Tg C in aboveground biomass, and 1,055–1,540 Tg C in the upper 1 m of soils). Potential CO2 emissions from current VCE losses are estimated at 2.1–3.1 Tg CO2-e yr-1, increasing annual CO2 emissions from land use change in Australia by 12–21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions

Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

© 2019, The Author(s). Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO2 emission benefits of VCE conservation and restoration. Australia contributes 5–11% of the C stored in VCE globally (70–185 Tg C in aboveground biomass, and 1,055–1,540 Tg C in the upper 1 m of soils). Potential CO2 emissions from current VCE losses are estimated at 2.1–3.1 Tg CO2-e yr-1, increasing annual CO2 emissions from land use change in Australia by 12–21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions

Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

Unidad de excelencia María de Maeztu MdM-2015-0552Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO emission benefits of VCE conservation and restoration. Australia contributes 5-11% of the C stored in VCE globally (70-185 Tg C in aboveground biomass, and 1,055-1,540 Tg C in the upper 1 m of soils). Potential CO emissions from current VCE losses are estimated at 2.1-3.1 Tg CO-e yr, increasing annual CO emissions from land use change in Australia by 12-21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions

Sediment and carbon deposition vary among vegetation assemblages in a coastal salt marsh

Coastal salt marshes are dynamic, intertidal ecosystems that are increasingly being recognised for their contributions to ecosystem services, including carbon (C) accumulation and storage. The survival of salt marshes and their capacity to store C under rising sea levels, however, is partially reliant upon sedimentation rates and influenced by a combination of physical and biological factors. In this study, we use several complementary methods to assess short-term (days) deposition and medium-term (months) accretion dynamics within a single marsh that contains three salt marsh vegetation types common throughout southeastern (SE) Australia. br br We found that surface accretion varies among vegetation assemblages, with medium-term (19 months) bulk accretion rates in the upper marsh rush (Juncus) assemblage (1.74g ±g 0.13g mmg yrg '1) consistently in excess of estimated local sea-level rise (1.15g mmg yrg '1). Accretion rates were lower and less consistent in both the succulent (Sarcocornia, 0.78g ±g 0.18g mmg yrg '1) and grass (Sporobolus, 0.88g ±g 0.22g mmg yrg '1) assemblages located lower in the tidal frame. Short-term (6 days) experiments showed deposition within Juncus plots to be dominated by autochthonous organic inputs with C deposition rates ranging from 1.14g ±g 0.41g mgg Cg cmg '2g dg '1 (neap tidal period) to 2.37g ±g 0.44g mgg Cg cmg '2g dg '1 (spring tidal period), while minerogenic inputs and lower C deposition dominated Sarcocornia (0.10g ±g 0.02 to 0.62g ±g 0.08g mgg Cg cmg '2g dg '1) and Sporobolus (0.17g ±g 0.04 to 0.40g ±g 0.07g mgg Cg cmg '2g dg '1) assemblages. br br Elemental (Cg :g N), isotopic (?13C), mid-infrared (MIR) and 13C nuclear magnetic resonance (NMR) analyses revealed little difference in either the source or character of materials being deposited among neap versus spring tidal periods. Instead, these analyses point to substantial redistribution of materials within the Sarcocornia and Sporobolus assemblages, compared to high retention and preservation of organic inputs in the Juncus assemblage. By combining medium-term accretion quantification with short-term deposition measurements and chemical analyses, we have gained novel insights into above-ground biophysical processes that may explain previously observed regional differences in surface dynamics among key salt marsh vegetation assemblages. Our results suggest that Sarcocornia and Sporobolus assemblages may be particularly susceptible to changes in sea level, though quantification of below-ground processes (e.g. root production, compaction) is needed to confirm this