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Ken Caldeira - One of the best experts on this subject based on the ideXlab platform.
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expected limits on the ocean acidification buffering potential of a temperate seagrass meadow
Ecological Applications, 2018Co-Authors: David A Koweek, Kathryn Hewett, Brian Gaylord, Sarah N Giddings, Yuichiro Takeshita, Jennifer L Ruesink, Kerry J Nickols, John J Stachowicz, Richard C Zimmerman, Ken CaldeiraAbstract:Author(s): Koweek, David A; Zimmerman, Richard C; Hewett, Kathryn M; Gaylord, Brian; Giddings, Sarah N; Nickols, Kerry J; Ruesink, Jennifer L; Stachowicz, John J; Takeshita, Yuichiro; Caldeira, Ken | Abstract: Ocean acidification threatens many marine organisms, especially marine calcifiers. The only global-scale solution to ocean acidification remains rapid reduction in CO2 emissions. Nevertheless, interest in localized mitigation strategies has grown rapidly because of the recognized threat ocean acidification imposes on natural communities, including ones important to humans. Protection of seagrass Meadows has been considered as a possible approach for localized mitigation of ocean acidification due to their large standing stocks of organic carbon and high productivity. Yet much work remains to constrain the magnitudes and timescales of potential buffering effects from seagrasses. We developed a biogeochemical box model to better understand the potential for a temperate seagrass meadow to locally mitigate the effects of ocean acidification. Then we parameterized the model using data from Tomales Bay, an inlet on the coast of California, USA which supports a major oyster farming industry. We conducted a series of month-long model simulations to characterize processes that occur during summer and winter. We found that average pH in the seagrass Meadows was typically within 0.04 units of the pH of the primary source waters into the meadow, although we did find occasional periods (hours) when seagrass metabolism may modify the pH by up to ±0.2 units. Tidal phasing relative to the diel cycle modulates localized pH buffering within the seagrass meadow such that maximum buffering occurs during periods of the year with midday low tides. Our model results suggest that seagrass metabolism in Tomales Bay would not provide long-term ocean acidification mitigation. However, we emphasize that our model results may not hold in Meadows where assumptions about depth-averaged net production and seawater residence time within the seagrass meadow differ from our model assumptions. Our modeling approach provides a framework that is easily adaptable to other seagrass Meadows in order to evaluate the extent of their individual buffering capacities. Regardless of their ability to buffer ocean acidification, seagrass Meadows maintain many critically important ecosystem goods and services that will be increasingly important as humans increasingly affect coastal ecosystems.
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expected limits on the ocean acidification buffering potential of a temperate seagrass meadow
Ecological Applications, 2018Co-Authors: David A Koweek, Kathryn Hewett, Brian Gaylord, Sarah N Giddings, Yuichiro Takeshita, Jennifer L Ruesink, Kerry J Nickols, John J Stachowicz, Richard C Zimmerman, Ken CaldeiraAbstract:Ocean acidification threatens many marine organisms, especially marine calcifiers. The only global-scale solution to ocean acidification remains rapid reduction in CO2 emissions. Nevertheless, interest in localized mitigation strategies has grown rapidly because of the recognized threat ocean acidification imposes on natural communities, including ones important to humans. Protection of seagrass Meadows has been considered as a possible approach for localized mitigation of ocean acidification due to their large standing stocks of organic carbon and high productivity. Yet much work remains to constrain the magnitudes and timescales of potential buffering effects from seagrasses. We developed a biogeochemical box model to better understand the potential for a temperate seagrass meadow to locally mitigate the effects of ocean acidification. Then we parameterized the model using data from Tomales Bay, an inlet on the coast of California, USA which supports a major oyster farming industry. We conducted a series of month-long model simulations to characterize processes that occur during summer and winter. We found that average pH in the seagrass Meadows was typically within 0.04 units of the pH of the primary source waters into the meadow, although we did find occasional periods (hours) when seagrass metabolism may modify the pH by up to ±0.2 units. Tidal phasing relative to the diel cycle modulates localized pH buffering within the seagrass meadow such that maximum buffering occurs during periods of the year with midday low tides. Our model results suggest that seagrass metabolism in Tomales Bay would not provide long-term ocean acidification mitigation. However, we emphasize that our model results may not hold in Meadows where assumptions about depth-averaged net production and seawater residence time within the seagrass meadow differ from our model assumptions. Our modeling approach provides a framework that is easily adaptable to other seagrass Meadows in order to evaluate the extent of their individual buffering capacities. Regardless of their ability to buffer ocean acidification, seagrass Meadows maintain many critically important ecosystem goods and services that will be increasingly important as humans increasingly affect coastal ecosystems.
Carlos M. Duarte - One of the best experts on this subject based on the ideXlab platform.
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photosynthetic activity buffers ocean acidification in seagrass Meadows
Biogeosciences, 2013Co-Authors: Iris E Hendriks, Ylva S Olsen, Laura Ramajo, Lorena Basso, Alexandra Steckbauer, Tommy S Moore, Jason L Howard, Carlos M. DuarteAbstract:Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5–12 m) seagrass ( Posidonia oceanica ) Meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (Ω Ar )) and O 2 within the Meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pH NBS and max and range Ω Ar . In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min Ω Ar , while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range Ω Ar within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, Ω Ar and carbonate deposition. Calcifying organisms, e.g. epiphytes with carbonate skeletons, may benefit from the modification of the carbonate system by the meadow. There is, however, concern for the ability of seagrasses to provide modifications of similar importance in the future. The predicted decline of seagrass Meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, on which LAI is based. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded Meadows.
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seagrass Meadows modify drag forces on the shell of the fan mussel pinna nobilis
Estuaries and Coasts, 2011Co-Authors: Iris E Hendriks, Miguel Cabanellasreboredo, Salud Deudero, Tjeerd J Bouma, Carlos M. DuarteAbstract:We assess the sheltering effect of Posidonia oceanica Meadows on drag forces exerted on shells of the fan mussel Pinna nobilis. We examine a range of shell sizes under four unidirectional flow speeds (0.05–0.34 m s−1) and two oscillating regimes. Three meadow densities are evaluated and a control without vegetation. We found that the attenuating effect of the meadow on drag forces experienced by bivalves is determined by the form of the hydrodynamic energy, e.g., as unidirectional flow or wave action. In tidal currents, the meadow protects most sizes of bivalves, with a higher efficiency for dense Meadows, while in wave dominant zones the meadow reduces drag forces for bivalves with shell areas below a threshold of 0.019 m2, whereas larger animals experience increased drag forces within the meadow independent of meadow density. Reduction of shoot density in seagrass Meadows might therefore not affect the effectiveness of the canopy to reduce drag forces on associated species like the fan mussel in wave-dominated areas while increased storm frequency could result into losses of larger individuals during periods of high wave action.
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patterns of seagrass posidonia oceanica flowering in the western mediterranean
Marine Biology, 2006Co-Authors: Elena Diazalmela, Nuria Marba, Elvira Alvarez, Elena Balestri, Juan M Ruizfernandez, Carlos M. DuarteAbstract:The intensive reconstructive sampling (1957–2004, 39 localities), a systematic direct observation (1992–2004, 1 locality) and particular direct observations (66 localities) of Posidonia oceanica Meadows were analysed together with temporal series of flowering available in the literature (19 localities). This allowed the examination of temporal and spatial variability in annual flowering prevalence (FP, the fraction of Meadows flowering in a given year) and of annual meadow flowering intensity (FI, number of inflorescences per shoot) for the period 1979–2004 across the Western Mediterranean, as well as spatial variability of flowering frequency (FF, the fraction of years that a given meadow has flowered) and shoot flowering probability (Pf, fraction of flowering stalks appeared per annual segment). Each year, on an average 17% of the investigated Meadows flowered, ranging from 3 to 86% of Meadows among the years. The highest annual FP and FI values were obtained in 2003 (FP=0.86 and mean FI=0.23±0.03 inflorescences shoot−1). A secondary peak of FP and mean FI occurred 9 years earlier, in 1994 (FP=0.44 and mean FI=0.08±0.02). Both peaks of flowering occurred after hot summers. Flowering synchrony in particular years across the Western Mediterranean and clines of increased meadow flowering frequency towards the North and East, suggests the existence of large-scale environmental mechanisms controlling the floral induction. On the other hand, meadow FF and Pf were highly heterogeneous among and within the Meadows, indicating that local factors also may play a significant role in flowering induction. When flowering, the Western Mediterranean Meadows showed an average 0.11±0.02 inflorescences shoot−1, but FI greatly varied among and along the series (from 0.002 to 0.54 inflorescences shoot−1) and decreased significantly with depth but was independent of meadow shoot density and meadow latitude or longitude. The shoot flowering probability was quite low (0.007±0.002 inflorescences shoot−1 year−1) and exponentially increased with shoot age.
Gaolin Wu - One of the best experts on this subject based on the ideXlab platform.
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long term fencing improved soil properties and soil organic carbon storage in an alpine swamp meadow of western china
Plant and Soil, 2010Co-Authors: Jimin Chen, Gaolin Wu, Lei Zhang, Tianming HuAbstract:Overgrazing significantly affects alpine Meadows in ways similar to grasslands in other areas. Fencing to exclude grazers is one of the main management practices used to protect alpine Meadows. However, it is not known if fencing can improve soil properties and soil organic carbon storage by restraining grazing in alpine Meadows. We studied the long-term (nine-year) effects of fencing on soil properties, soil organic carbon and nitrogen storage compared with continued grazing in an alpine swamp meadow of the Qinghai–Tibetan Plateau, NW China. Our results showed that fencing significantly improved vegetation cover and aboveground biomass. There were significant effects of fencing on pH value, soil bulk density, and soil moisture. Long-term fencing favored the increase of soil total nitrogen, soil organic matter, soil organic carbon, soil microbial biomass carbon and soil carbon storage compared with grazed Meadows. Our study suggests that long-term fencing to prevent disturbance could greatly affect soil organic carbon and nitrogen storage with regard to grazed Meadows. Therefore, it is apparent from this study that fencing is an effective restoration approach of with regard to the soil’s storage ability for carbon and nitrogen in alpine meadow of the Qinghai–Tibetan Plateau.
Jens Schirmel - One of the best experts on this subject based on the ideXlab platform.
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plant functional shifts in central european grassland under traditional flood irrigation
Applied Vegetation Science, 2016Co-Authors: Isabell Mulle, Martin H. Entling, Constanze Uhk, Jens SchirmelAbstract:Aims Lowland meadow irrigation used to be a widespread management practice to improve hay yield in Central European grasslands. Recently, traditional meadow irrigation is being re-established in some parts of Europe. Nevertheless, the consequences of the regular artificial flooding on vegetation of these water Meadows remain poorly understood. We studied the impact of flood irrigation on the plant functional and species composition of extensively managed hay Meadows. Location Lowland of River Queich, between Landau and Lustadt, Germany. Methods We sampled vegetation in 34 Meadows that differed in irrigation status (irrigated/non-irrigated) and fertilization (unfertilized/fertilized). Plants were classified into functional groups according to growth forms, N-fixing ability and reproductive strategy. Effects of meadow irrigation on the plant functional composition were analysed using two complementary approaches. In the ‘community approach’, we analysed total cover of each functional group per meadow with respect to irrigation and fertilization. In the ‘species approach’, we analysed the mean response to irrigation among the species within the defined functional groups. Results Total cover of rosettes and semi-rosettes increased relative to graminoids in irrigated Meadows. Cover of legumes was three times higher in irrigated compared to non-irrigated Meadows. Irrigation enhanced preferences for seed and vegetative reproduction. However, the response of individual species within the functional groups was inconsistent. Fertilization had an overall minor influence on functional composition of the Meadows. Conclusions The higher proportion of plants with basal growth organs in irrigated Meadows suggests that irrigation may enhance a more complex vertical structure of the vegetation. Enhancement of rosettes, semi-rosettes and legumes at the cost of graminoids through irrigation was more significant in the community than in the species approach, indicating that the functional group response was amplified by the respective dominant species. This highlights the importance of considering species-level interactions in functional vegetation analysis.
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effects of traditional flood irrigation on invertebrates in lowland Meadows
PLOS ONE, 2014Co-Authors: Jens Schirmel, Isabell Rudolph, Martin H. EntlingAbstract:Lowland meadow irrigation used to be widespread in Central Europe, but has largely been abandoned during the 20th century. As a result of agri-environment schemes and nature conservation efforts, meadow irrigation is now being re-established in some European regions. In the absence of natural flood events, irrigation is expected to favour fauna typical of lowland wet Meadows. We analysed the effects of traditional flood irrigation on diversity, densities and species composition of three invertebrate indicator taxa in lowland Meadows in Germany. Unexpectedly, alpha diversity (species richness and Simpson diversity) and beta diversity (multivariate homogeneity of group dispersions) of orthopterans, carabids, and spiders were not significantly different between irrigated and non-irrigated Meadows. However, spider densities were significantly higher in irrigated Meadows. Furthermore, irrigation and elevated humidity affected species composition and shifted assemblages towards moisture-dependent species. The number of species of conservation concern, however, did not differ between irrigated and non-irrigated Meadows. More variable and intensive (higher duration and/or frequency) flooding regimes might provide stronger conservation benefits, additional species and enhance habitat heterogeneity on a landscape scale.
David A Koweek - One of the best experts on this subject based on the ideXlab platform.
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expected limits on the ocean acidification buffering potential of a temperate seagrass meadow
Ecological Applications, 2018Co-Authors: David A Koweek, Kathryn Hewett, Brian Gaylord, Sarah N Giddings, Yuichiro Takeshita, Jennifer L Ruesink, Kerry J Nickols, John J Stachowicz, Richard C Zimmerman, Ken CaldeiraAbstract:Author(s): Koweek, David A; Zimmerman, Richard C; Hewett, Kathryn M; Gaylord, Brian; Giddings, Sarah N; Nickols, Kerry J; Ruesink, Jennifer L; Stachowicz, John J; Takeshita, Yuichiro; Caldeira, Ken | Abstract: Ocean acidification threatens many marine organisms, especially marine calcifiers. The only global-scale solution to ocean acidification remains rapid reduction in CO2 emissions. Nevertheless, interest in localized mitigation strategies has grown rapidly because of the recognized threat ocean acidification imposes on natural communities, including ones important to humans. Protection of seagrass Meadows has been considered as a possible approach for localized mitigation of ocean acidification due to their large standing stocks of organic carbon and high productivity. Yet much work remains to constrain the magnitudes and timescales of potential buffering effects from seagrasses. We developed a biogeochemical box model to better understand the potential for a temperate seagrass meadow to locally mitigate the effects of ocean acidification. Then we parameterized the model using data from Tomales Bay, an inlet on the coast of California, USA which supports a major oyster farming industry. We conducted a series of month-long model simulations to characterize processes that occur during summer and winter. We found that average pH in the seagrass Meadows was typically within 0.04 units of the pH of the primary source waters into the meadow, although we did find occasional periods (hours) when seagrass metabolism may modify the pH by up to ±0.2 units. Tidal phasing relative to the diel cycle modulates localized pH buffering within the seagrass meadow such that maximum buffering occurs during periods of the year with midday low tides. Our model results suggest that seagrass metabolism in Tomales Bay would not provide long-term ocean acidification mitigation. However, we emphasize that our model results may not hold in Meadows where assumptions about depth-averaged net production and seawater residence time within the seagrass meadow differ from our model assumptions. Our modeling approach provides a framework that is easily adaptable to other seagrass Meadows in order to evaluate the extent of their individual buffering capacities. Regardless of their ability to buffer ocean acidification, seagrass Meadows maintain many critically important ecosystem goods and services that will be increasingly important as humans increasingly affect coastal ecosystems.
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expected limits on the ocean acidification buffering potential of a temperate seagrass meadow
Ecological Applications, 2018Co-Authors: David A Koweek, Kathryn Hewett, Brian Gaylord, Sarah N Giddings, Yuichiro Takeshita, Jennifer L Ruesink, Kerry J Nickols, John J Stachowicz, Richard C Zimmerman, Ken CaldeiraAbstract:Ocean acidification threatens many marine organisms, especially marine calcifiers. The only global-scale solution to ocean acidification remains rapid reduction in CO2 emissions. Nevertheless, interest in localized mitigation strategies has grown rapidly because of the recognized threat ocean acidification imposes on natural communities, including ones important to humans. Protection of seagrass Meadows has been considered as a possible approach for localized mitigation of ocean acidification due to their large standing stocks of organic carbon and high productivity. Yet much work remains to constrain the magnitudes and timescales of potential buffering effects from seagrasses. We developed a biogeochemical box model to better understand the potential for a temperate seagrass meadow to locally mitigate the effects of ocean acidification. Then we parameterized the model using data from Tomales Bay, an inlet on the coast of California, USA which supports a major oyster farming industry. We conducted a series of month-long model simulations to characterize processes that occur during summer and winter. We found that average pH in the seagrass Meadows was typically within 0.04 units of the pH of the primary source waters into the meadow, although we did find occasional periods (hours) when seagrass metabolism may modify the pH by up to ±0.2 units. Tidal phasing relative to the diel cycle modulates localized pH buffering within the seagrass meadow such that maximum buffering occurs during periods of the year with midday low tides. Our model results suggest that seagrass metabolism in Tomales Bay would not provide long-term ocean acidification mitigation. However, we emphasize that our model results may not hold in Meadows where assumptions about depth-averaged net production and seawater residence time within the seagrass meadow differ from our model assumptions. Our modeling approach provides a framework that is easily adaptable to other seagrass Meadows in order to evaluate the extent of their individual buffering capacities. Regardless of their ability to buffer ocean acidification, seagrass Meadows maintain many critically important ecosystem goods and services that will be increasingly important as humans increasingly affect coastal ecosystems.