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Short-Term Spatial and Temporal Carbonate Chemistry Variability in Two Contrasting Seagrass Meadows : Implications for pH Buffering Capacities

Cyronak, Tyler; Andersson, Andreas J.; D’Angelo, Sydney; Bresnahan, Philip; Davidson, Charles; Griffin, Alyssa; Kindeberg, Theodor LU ; Pennise, Jimmy; Takeshita, Yuichiro and White, Margot (2018) In Estuaries and Coasts 41(5). p.1282-1296
Abstract

It has been hypothesized that highly productive coastal ecosystems, such as seagrass meadows, could lead to the establishment of ocean acidification (OA) refugia, or areas of elevated pH and aragonite saturation state (Ωa) compared to source seawater. However, seagrass ecosystems experience extreme variability in carbonate chemistry across short temporal and small spatial scales, which could impact the pH buffering capacity of these potential refugia. Herein, short-term (hourly to diel) and small-scale (across 0.01–0.14 km2) spatiotemporal carbonate chemistry variability was assessed within two seagrass meadows in order to determine their short-term potential to elevate seawater pH relative to source seawater. Two... (More)

It has been hypothesized that highly productive coastal ecosystems, such as seagrass meadows, could lead to the establishment of ocean acidification (OA) refugia, or areas of elevated pH and aragonite saturation state (Ωa) compared to source seawater. However, seagrass ecosystems experience extreme variability in carbonate chemistry across short temporal and small spatial scales, which could impact the pH buffering capacity of these potential refugia. Herein, short-term (hourly to diel) and small-scale (across 0.01–0.14 km2) spatiotemporal carbonate chemistry variability was assessed within two seagrass meadows in order to determine their short-term potential to elevate seawater pH relative to source seawater. Two locations at similar latitudes were chosen in order to compare systems dominated by coarse calcium carbonate (Bailey’s Bay, Bermuda) and muddy silicate (Mission Bay, CA, USA) sediments. In both systems, spatial variability of pH across the seagrass meadow at any given time was often greater than diel variability (e.g., the average range over 24 h) at any one site, with greater spatial variability occurring at low tide in Mission Bay. Mission Bay (spatial ΔpH = 0.08 ± 0.08; diel ΔpH = 0.12 ± 0.01; mean ± SD) had a greater average range in both temporal and spatial seawater chemistry than Bailey’s Bay (spatial ΔpH = 0.02 ± 0.01; diel ΔpH = 0.03 ± 0.00; mean ± SD). These differences were most likely due to a combination of slower currents, a larger tidal range, and more favorable weather conditions for photosynthesis (e.g., sunny with no rain) in Mission Bay. In both systems, there was a substantial amount of time (usually at night) when seawater pH within the seagrass beds was lower relative to the source seawater. Future studies aimed at assessing the potential of seagrass ecosystems to act as OA refugia for marine organisms need to account for the small-scale, high-frequency carbonate chemistry variability in both space and time, as this variability will impact where and when OA will be buffered or intensified.

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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Buffering, Carbonate chemistry, Coastal ecosystems, Ocean acidification, Seagrass, SeapHOx
in
Estuaries and Coasts
volume
41
issue
5
pages
1282 - 1296
publisher
Estuarine Research Federation
external identifiers
  • scopus:85040024285
ISSN
1559-2723
DOI
10.1007/s12237-017-0356-5
language
English
LU publication?
no
id
426d1538-9663-4435-aa3e-5118dff590f9
date added to LUP
2019-03-07 14:52:11
date last changed
2019-11-13 05:27:58
@article{426d1538-9663-4435-aa3e-5118dff590f9,
  abstract     = {<p>It has been hypothesized that highly productive coastal ecosystems, such as seagrass meadows, could lead to the establishment of ocean acidification (OA) refugia, or areas of elevated pH and aragonite saturation state (Ω<sub>a</sub>) compared to source seawater. However, seagrass ecosystems experience extreme variability in carbonate chemistry across short temporal and small spatial scales, which could impact the pH buffering capacity of these potential refugia. Herein, short-term (hourly to diel) and small-scale (across 0.01–0.14 km<sup>2</sup>) spatiotemporal carbonate chemistry variability was assessed within two seagrass meadows in order to determine their short-term potential to elevate seawater pH relative to source seawater. Two locations at similar latitudes were chosen in order to compare systems dominated by coarse calcium carbonate (Bailey’s Bay, Bermuda) and muddy silicate (Mission Bay, CA, USA) sediments. In both systems, spatial variability of pH across the seagrass meadow at any given time was often greater than diel variability (e.g., the average range over 24 h) at any one site, with greater spatial variability occurring at low tide in Mission Bay. Mission Bay (spatial ΔpH = 0.08 ± 0.08; diel ΔpH = 0.12 ± 0.01; mean ± SD) had a greater average range in both temporal and spatial seawater chemistry than Bailey’s Bay (spatial ΔpH = 0.02 ± 0.01; diel ΔpH = 0.03 ± 0.00; mean ± SD). These differences were most likely due to a combination of slower currents, a larger tidal range, and more favorable weather conditions for photosynthesis (e.g., sunny with no rain) in Mission Bay. In both systems, there was a substantial amount of time (usually at night) when seawater pH within the seagrass beds was lower relative to the source seawater. Future studies aimed at assessing the potential of seagrass ecosystems to act as OA refugia for marine organisms need to account for the small-scale, high-frequency carbonate chemistry variability in both space and time, as this variability will impact where and when OA will be buffered or intensified.</p>},
  author       = {Cyronak, Tyler and Andersson, Andreas J. and D’Angelo, Sydney and Bresnahan, Philip and Davidson, Charles and Griffin, Alyssa and Kindeberg, Theodor and Pennise, Jimmy and Takeshita, Yuichiro and White, Margot},
  issn         = {1559-2723},
  keyword      = {Buffering,Carbonate chemistry,Coastal ecosystems,Ocean acidification,Seagrass,SeapHOx},
  language     = {eng},
  month        = {07},
  number       = {5},
  pages        = {1282--1296},
  publisher    = {Estuarine Research Federation},
  series       = {Estuaries and Coasts},
  title        = {Short-Term Spatial and Temporal Carbonate Chemistry Variability in Two Contrasting Seagrass Meadows : Implications for pH Buffering Capacities},
  url          = {http://dx.doi.org/10.1007/s12237-017-0356-5},
  volume       = {41},
  year         = {2018},
}