Plaster standards to measure water motion

Thompson, T. Lewis; Glenn, Edward P.

doi:10.4319/lo.1994.39.7.1768

Cited by 127 publications

(88 citation statements)

References 8 publications

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“…From these excellent relationships it has often been assumed that it was steady flow speed or current velocity that was measured in the field (e.g., Petticrew and Kalff 1991;Komatsu and Murakami 1994). Moreover, it has been suggested that gypsumdissolution rates be calibrated to flow speeds and reported in velocity units (Thompson and Glenn 1994). In addition, Petticrew and Kalff (1991) suggested that the gypsum-dissolution technique could potentially be used as a turbulence sensor; however, they calibrated dissolution rates exclusively to steady flow speed.…”

Section: Discussionmentioning

confidence: 99%

“…Still-water calibrations to determine this as a ''measure of the degree to which diffusion or dissolution was enhanced by water movement'' (Doty 1971) have given variable results (Muus 1968;Doty 1971) but have been widely used. The variability in the stillwater measurements has been attributed to the small water volume used (Jokiel and Morrissey 1993;Thompson and Glenn 1994), which may have led to less of a concentration gradient in the diffusive boundary layer, and thus a low dissolution rate or saturation of Ca 2ϩ . In addition, the variability has been attributed to placing gypsum devices too close to the bottom of containers (Thompson and Glenn 1994), thereby decreasing the concentration gradient in the diffusive boundary layer and decreasing dissolution rates.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, he noted that results obtained from several tidal cycles were difficult to replicate (Doty 1971). Jokiel and Morrissey (1993) cautioned against the use of stillwater controls used to obtain a diffusion factor, and Thompson and Glenn (1994) recommended discontinuing the use of still-water controls because of the variability introduced. Nixon et al (1980) speculated that turbulence may have contributed to dissolution rates in their studies.…”

mentioning

confidence: 99%

“…The dissolution of gypsum or gypsum-based plaster of Paris from ''plaster balls'' or ''clod cards'' was first introduced by Muus (1968) and Doty (1971) as an inexpensive technique to measure water flow in the absence of expensive field instrumentation for direct measurements of water velocity. Effects of temperature, salinity, and water volume on dissolution rates were subsequently investigated by Jokiel and Morrissey (1993) and Thompson and Glenn (1994). Since its first introduction, the gypsum-dissolution technique has been widely used in many habitats and for many applications, especially for studies of physical-biological interactions (Table 1).…”

mentioning

confidence: 99%

“…, Thompson & Glenn (1994) 42 , West (1997) 43 , Yamahira Water motion (DF) 5,9,11,16,42; (DF-fs) 5,14,19,20,23; (fs-f) 19,30,44; (fs-r) 15, 42; (m) 16,26,28,42,43 5, 19, 26; (ms) 9, 11, 14, 19, 23, 28; (se) 14, 15, 28; (ss) 9, 16, 19, 23, 30, 42; (w) 5, 19, 42 (ad) 16, 19, 23, 26, 30, 42; (bf) Gerard (1982) used gypsum buttons calibrated in a flume to calculate flows in a dense macrophyte forest. She estimated flow speeds of about 4 cm s Ϫ1 with this technique, even though the in situ flow speeds had appeared much lower to her, on the order of 1 cm s Ϫ1 .…”

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confidence: 99%

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Gypsum dissolution is not a universal integrator of ‘water motion’

Porter

Sanford

Suttles

2000

Limnology & Oceanography

104

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The dissolution of gypsum or plaster of Paris has been widely used as an inexpensive integral measure of 'water motion' in the field and in laboratory tanks for studies of physical-biological interactions. Commonly, gypsumdissolution rates have been calibrated to steady flow speed or velocity in the laboratory and the calibrations have been applied to dissolution (i.e., mass-transfer) rates in the field or in tanks. We evaluated the gypsum-dissolution technique in a steady-flow, a fluctuating-flow, and a mixed-flow environment by comparing dissolution rate to direct flow measurements with an acoustic Doppler velocimeter. We found that dissolution rates were related to steady flow and to fluctuation intensity in the exclusively steady-flow and fluctuating-flow environments, respectively. The relationships were weak in the mixed-flow environment. Finally, dissolution and thus mass-transfer relationships were different in each flow environment, and the effects of steady flow and fluctuation intensity were not additive. Providing that it is rigorously checked and appropriately calibrated, the dissolution technique can be used to measure steady flow speed or fluctuation intensity in a steady-flow or fluctuating-flow environment, respectively. However, comparisons of dissolution rates between steady-flow, fluctuating-flow, and mixed-flow environments or within environments that change over time to determine water motion will be misleading. The gypsum-dissolution technique can be used as a good direct indicator of mass-transfer rates. However, mass-transfer rates are different in different flow environments. The gypsum-dissolution technique is not a universal integrator of 'water motion. ' The dissolution of gypsum or gypsum-based plaster of Paris from ''plaster balls'' or ''clod cards'' was first introduced by Muus (1968) and Doty (1971) as an inexpensive technique to measure water flow in the absence of expensive field instrumentation for direct measurements of water velocity. Effects of temperature, salinity, and water volume on dissolution rates were subsequently investigated by Jokiel and Morrissey (1993) and Thompson and Glenn (1994). Since its first introduction, the gypsum-dissolution technique has been widely used in many habitats and for many applications, especially for studies of physical-biological interactions (Table 1). The gypsum-dissolution technique has been thought to provide a comparative or absolute measure of water movement that ''incorporates any water motion due to tidal as well as wind-wave effects in the same integrated measure' ' (Wildish and Kristmanson 1997). Furthermore, the dissolution technique has expanded to include materials other than gypsum (e.g., Koehl and Alberte 1988;Bartol et al. 1999). AcknowledgmentsWe thank W. Boicourt for letting us participate in the field ''Tower'' experiment and for providing the temperature and salinity data to calibrate the field-dissolution results. We thank K. Sebens, D. Stoecker, V. Kennedy, M. Palmer, and three anonymous reviewers for ...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Gypsum dissolution is not a universal integrator of ‘water motion’

Porter

Sanford

Suttles

2000

Limnology & Oceanography

104

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Tidal channel meanders serve as stepping‐stones to facilitate cordgrass landward spread by creating invasion windows

Ning

Cui

Chen

et al. 2023

Ecological Applications

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Understanding the mechanisms by which the geomorphic structures affect habitat invasibility by mediating various abiotic and biotic factors is essential for predicting whether these geomorphic structures may provide spatial windows of opportunity to facilitate range‐expansion of invasive species in salt marshes. Many studies have linked geomorphic landscape features such as tidal channels to invasion by exotic plants, but the role of tidal channel meanders (i.e., convex and concave sides) in regulating the Spartina alterniflora invasion remains unclear. Here, we examined the combined effects of tidal channel meander‐mediated hydrodynamic variables, soil abiotic stresses, and propagule pressure on the colonization of Spartina in the Yellow River Delta, China, by conducting field observations and experiments. The results showed that lower hydrodynamic disturbance, bed shear stress, and higher propagule pressure triggered by eddies due to the convex structure of channel meanders facilitated Spartina seedling establishment and growth, whereas the concave side considerably inhibited the Spartina invasion. Lower soil abiotic stresses also significantly promoted the invasibility of the channel meanders by Spartina. Based on these findings, we propose a conceptual framework to illustrate the effects of the meandering geomorphology of tidal channels on the mechanisms that might allow the landward spread of Spartina and related processes. Our results demonstrate that the meandering geomorphic structures of tidal channels could act as stepping‐stones to significantly facilitate the landward invasion of Spartina along tidal channels. This implies that geomorphic characteristics of tidal channels should be integrated into invasive species control and salt marsh management strategies.

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