Thermal tolerance of two seagrass species at contrasting light levels: Implications for future distribution in the Great Barrier Reef

Collier, Catherine; Uthicke, Sven; Waycott, Michelle

doi:10.4319/lo.2011.56.6.2200

Cited by 120 publications

(109 citation statements)

References 25 publications

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“…In situ temperature increased in comparison with our control temperature during the course of the experiment. Longterm water temperatures for this region are available (at: http://data.aims.gov.au/aimsrtds/latestreadings.xhtml, see also Collier et al 2012;Lamare et al 2014) from a 4-m deep station at Davies Reef (18°49.8 0 S, 147°37.8°E), a similar midshelf reef to Rib Reef.…”

Section: Resultsmentioning

confidence: 99%

Interactive effects of near-future temperature increase and ocean acidification on physiology and gonad development in adult Pacific sea urchin, Echinometra sp. A

et al. 2014

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Increased atmospheric CO 2 will have a twofold impact on future marine ecosystems, increasing global sea surface temperatures and uptake of CO 2 (Ocean Acidification). Many experiments focus on the investigation of one of these stressors, but under realistic future climate predictions, these stressors may have interactive effects on individuals. Here, we investigate the effect of warming and acidification in combination. We test for interactive effects of potential near-future (2100) temperature (?2 to 3°C) and pCO 2 (*860-940 lAtm) levels on the physiology of the tropical echinoid Echinometra sp. A. The greatest reduction in growth was under simultaneous temperature and pH/pCO 2 stress (marginally significant temperature 9 pH/pCO 2 interaction). This was mirrored by the physiological data, with highest metabolic activity (measured as respiration and ammonium excretion) occurring at the increased temperature and pCO 2 treatment, although this was not significant for excretion. The perivisceral coelomic fluid pH was *7.5-7.6, as typical for echinoids, and showed no significant changes between treatments. Indicative of active calcification, internal magnesium and calcium concentrations were reduced compared to the external medium, but were not different between treatments. Gonad weight was lower at the higher temperature, and this difference was more distinct and statistically significant for males. The condition of the gonads assessed by histology declined in increased temperature and low pH treatments. The Echinometra grew in all treatments indicating active calcification of their magnesium calcite tests even as carbonate mineral saturation decreased. Our results indicate that the interactive temperature and pH effects are more important for adult echinoids than individual stressors. Although adult specimens grow and survive in nearfuture conditions, higher energy demands may influence gonad development and thus population maintenance.

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Section: Resultsmentioning

confidence: 99%

Interactive effects of near-future temperature increase and ocean acidification on physiology and gonad development in adult Pacific sea urchin, Echinometra sp. A

et al. 2014

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“…With increased light attenuation through the water column, the optimal temperature for seagrass photosynthesis declines because of the high respiratory demands , Lee et al 2007. During the summer at shallow water depths, temperatures are higher than at deeper depths which increases the amount of light needed for growth (Lee et al 2005); however, because these plants are at shallower depths they may have enough light for growth even with high temperatures (Collier et al 2011). Reductions in light during the summer months can further increase the amount of stress on seagrasses, reducing growth (Lee et al 2007, Lee et al 2005.…”

Section: Temperaturementioning

confidence: 99%

Section: Temperaturementioning

confidence: 99%

“…Seagrass metabolism is sensitive to changes in temperature, specifically temperature increases (Collier et al 2011, Winters et al 2011. When temperatures exceed thresholds for seagrass species, 28°C for Z. marina Jarvis 2008, Moore et al 2012), respiration exceeds photosynthesis causing a carbon deficit within the plant, decreasing growth and aboveground biomass , Collier et al 2011, Olsen et al 2012. With the predicted average increase of 1.3°C of coastal water temperatures before 2100 (Najjar et al 2000), many seagrasses at the warm latitudinal limit for their growth may experience decline (Collier et al 2011, Massa et al 2009).…”

Section: Temperaturementioning

confidence: 99%

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Sustainable Seagrass Restoration in the Virginia Coastal Bays

Al‐Haj¹

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1Seagrass depth limits are important to consider when thinking about the future of coastal 2 ecosystems through climate change and nutrient loading scenarios. Seagrasses provide many 3 ecosystem services to coastal areas worldwide, including providing habitat for many 4 economically important species, acting as a significant carbon sink, and improving water quality. 5Because seagrasses are declining globally, it is important to be able to identify areas for 6 restoration where seagrasses could be successful in order to maximize use of time and money. 7Current models for the Virginia Coast Reserve (VCR) only consider effects of light and point 8 measurements of temperature on the maximum depth limit for eelgrass. However, it has been 9 shown that multiple factors can affect light requirements in plants such as sediment 10 characteristics and pore-water chemistry. Sediment characteristics, such as grain size and organic 11 matter content increase light requirements in plants by physically blocking light and decreasing 12 oxygen concentrations in the sediments allowing for the intrusion of phytotoxins such as pore-13 water sulfide and ammonium. With climate change causing a rise in global temperatures, 14 seagrasses will become even more sensitive to changes in their light environment, such as those 15 caused by coastal eutrophication, and will need to increase light requirements further to maintain 16 a positive carbon balance. This may affect depth limits in seagrasses by limiting their range for 17 growth at the minimum depth limit due to increases in temperature and at the maximum depth 18 limit due to declining light conditions with depth. Because the persistence of restoration projects 19 is dependent on the feedbacks between hydrodynamics, light attenuation, and temperature at the 20 meadow scale, it is important to consider the effects of light and temperature measurements over 21ii time in terms of other stressors such as pore-water chemistry and sediment characteristics to 22 accurately find the maximum and minimum depths for eelgrass growth. 23This thesis addresses how maximum and minimum depth limits change over an 24 environmental gradient of sediment grain size and organic matter content in the Virginia coastal 25 bays. The impact of changes in light attenuation in terms of water quality and temperature on 26 maximum and minimum depth limits was investigated through spatial analysis of field and 27 bathymetry data. The predicted depth ranges were compared to ranges of transplanted plants 28 along a depth gradient from 0.4 m to 2.0 m MSL (mean sea level) bracketing the known range 29 for eelgrass growth in Hog Island Bay, 0.8 m to 1.6 m MSL. I found that the maximum depth 30 limit for eelgrass growth can be predicted by light levels in areas with low pore-water sulfide 31 concentrations; however, in areas with high sediment pore-water sulfide concentrations there 32 may be a more complex interaction occurring where light requirements increase due to sulfide 33 intrusion. Predicting the minimum...

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“…Species within the same latitudes may also exhibit differences in response to temperature (Collier et al 2011, Masini & Manning 1997, Perez & Romero 1992.…”

Section: Introductionmentioning

confidence: 99%

Assessing Physiological Thresholds for Eelgrass (Zostera Marina L.) Survival in the Face of Climate Change

Ewers¹

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Assessing physiological thresholds for eelgrass (Zostera marina L.) survival in the face of climate change Carolyn Jane Ewers Seagrasses are well known for the important ecological roles they play in coastal marine waters worldwide. However, the severe rate of decline observed in seagrasses this century is expected to accelerate with climate change. Conservation efforts can be improved by quantifying physiological thresholds of seagrasses and using these estimates in modeling to forecast changes in distribution. This study examines the response of eelgrass (Zostera marina L.) across current temperatures to look for early warning signs of vulnerability and to evaluate the ways we determine critical thresholds for survival. Whole eelgrass ramets, collected from three beds in Morro Bay, California, were used to develop photosynthesis-irradiance (P-I) curves from 10-20°C. Productivity was not affected by changes in temperature when traditionally measured as the lightsaturated photosynthetic rate to dark respiration rate (P:R) ratio. However, photosynthesis in light-limited conditions declined at higher temperatures, suggesting a decrease in productivity when coupled with the increased respiration rates observed at higher temperatures. Irradiance thresholds increased with temperature; critical irradiance was the most sensitive to increases in temperature due to the inclusion of overnight energy use, which also increases with temperature. Measurements of root and rhizome respiration, overnight respiration, and variation across eelgrass beds reveal that these are important components to consider when calculating survival thresholds to use in modeling. Differences in physiological responses across beds suggest that some eelgrass beds operate more efficiently than others in current conditions and are likely to be more resilient to the progressing stressors of climate change. Management of eelgrass in the face of climate change will require reliable distribution forecasts, and therefore accurate estimates of physiological thresholds, to guide mitigation and restoration efforts.

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Thermal tolerance of two seagrass species at contrasting light levels: Implications for future distribution in the Great Barrier Reef

Cited by 120 publications

References 25 publications

Interactive effects of near-future temperature increase and ocean acidification on physiology and gonad development in adult Pacific sea urchin, Echinometra sp. A

Interactive effects of near-future temperature increase and ocean acidification on physiology and gonad development in adult Pacific sea urchin, Echinometra sp. A

Sustainable Seagrass Restoration in the Virginia Coastal Bays

Assessing Physiological Thresholds for Eelgrass (Zostera Marina L.) Survival in the Face of Climate Change

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