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

Porter, Elka T.; Sanford, Lawrence P.; Suttles, Steven E.

doi:10.4319/lo.2000.45.1.0145

Cited by 104 publications

(76 citation statements)

References 78 publications

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“…Relative mass transport rates (measured by dissolution of chalk blocks; ref. 45) were 60% greater at the more wave-exposed site (ANOVA: P Ͻ 0.0001, F 1,14 ϭ 102.32). At this more waveexposed location there was no evidence for effects of nutrient additions on macrophyte biomass, abundances of functional The response variables are the average abundances of functional groups: filaments, polysiphonous͞thinly corticated, thin blades, heavily corticated, articulated corallines, fleshy crusts, and coralline crusts (35).…”

Section: Resultsmentioning

confidence: 98%

Nutrient loading and consumers: Agents of change in open-coast macrophyte assemblages

Nielsen

2003

Proc. Natl. Acad. Sci. U.S.A.

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Human activities are significantly altering nutrient regimes and the abundance of consumers in coastal ecosystems. A field experiment in an open-coast, upwelling ecosystem showed that small increases in nutrients increased the biomass and evenness of tide pool macrophytes where consumer abundance and nutrient loading rates were low. Consumers, when abundant, had negative effects on the diversity and biomass of macrophytes. Nutrient loading increases and consumers are less abundant and efficient as wave exposure increases along open coastlines. Experimentally reversing the natural state of nutrient supply and consumer pressure at a wave-protected site to match wave-exposed sites caused the structure of the macrophyte assemblage to converge on that found naturally in wave-exposed pools. The increases in evenness and abundance were driven by increases in structurally complex functional groups. In contrast, increased nutrient loading in semienclosed marine or estuarine ecosystems is typically associated with declines in macrophyte diversity because of increases in structurally simple and opportunistic functional groups. If nutrient concentration of upwelled waters changes with climatic warming or increasing frequency of El Niñ os, as predicted by some climate models, these results suggest that macrophyte abundance and evenness along wave-swept open-coasts will also change. Macrophytes represent a significant fraction of continental shelf production and provide important habitat for many marine species. The combined effects of shifting nutrient regimes and overexploitation of consumers may have unexpected consequences for the structure and functioning of open-coast communities.

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Section: Resultsmentioning

confidence: 98%

Nutrient loading and consumers: Agents of change in open-coast macrophyte assemblages

Nielsen

2003

Proc. Natl. Acad. Sci. U.S.A.

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“…Flow parameters that separately describe the mean flow, the time-variant component of the flow, or a ratio of these parameters, do not provide good bases for comparing mass-transfer rates (Williams and Carpenter 1998;Porter et al 2000;Thomas and Cornelisen 2003). We chose rms-flow speed as an appropriate velocity scale because it provides a measure of total water motion, regardless of whether the flow is steady or oscillatory.…”

Section: Discussionmentioning

confidence: 99%

“…The dissolution of plaster has been widely used in aquatic sciences to characterize water motion because plaster dissolution is mass-transfer limited (Muus 1968;Porter et al 2000). Mass-transfer correlations have been used to accurately predict rates of dissolution of gypsum-coated coral skeletons (Baird and Atkinson 1997).…”

Section: Acknowledgmentsmentioning

confidence: 99%

Effects of surface roughness and oscillatory flow on the dissolution of plaster forms: Evidence for nutrient mass transfer to coral reef communities

2005

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We dissolved plaster forms in seawater to examine the effects of surface roughness and flow conditions on masstransfer rates. Plaster blocks with varying roughness were dissolved under both steady and oscillatory flows between 7 and 43 cm s Ϫ1 yielding calcium mass-transfer coefficients (S Ca ) that varied from 0.5 to 3 m d Ϫ1. S Ca measured in a flume was 30-40% greater under oscillatory flow than under steady flow at flow speeds Ͻ10 cm s Ϫ1 ; this difference decreased with increasing flow speed. Plaster blocks with added millimeter-, centimeter-, and decimeter-scale roughness were dissolved under oscillatory flows between 2 and 26 cm s Ϫ1 on three different coral reef flats. Plaster dissolution rates in the field were linearly proportional to surface area regardless of the roughness scale. Variation in S Ca across different reef environments was less affected by whether the flow was steady or oscillatory (a factor of 1.2-1.6) than it was by flow speed alone (a factor of 4.7).Water motion is an important factor regulating the exchange of metabolites between reef communities and their surrounding environment. Rates of nutrient uptake (Atkinson and Bilger 1992; Thomas and Atkinson 1997), photosynthetic production (Dennison and Barnes 1988;Carpenter et al. 1991), and nitrogen fixation (Williams and Carpenter 1988;Carpenter et al. 1991) by coral and algae increase with greater water motion. This occurs as a result of changes in the rate at which dissolved compounds are physically transferred across concentration boundary layers adjacent to the surfaces of autotrophic organisms. Prior studies of metabolite mass transfer have been conducted using reef communities with morphologies incorporating multiple scales of roughness (10 Ϫ3 to 10 Ϫ1 m); however, little attention has been paid to the relative importance of varying roughness scales to total rates of metabolite mass transfer to reef communities. It is well known that autotrophic reef organisms exhibit morphologies that incorporate multiple scales of roughness (Kaandorp 1999). However, the success of correlating nutrient mass-transfer rates to bottom drag or frictional dissipation have led some investigators to suggest that small roughness scales are unimportant to total rates of metabolite mass transfer (Baird and Atkinson 1997;Hearn et al. 2001). In addition, most studies of water motion on coral and algal metabolism have been conducted under steady, unidirection-1 To whom correspondence should be addressed. Present address: MSB 205, 1000 Pope Road, Honolulu, Hawaii 96822 (falter@ hawaii.edu). AcknowledgmentsThanks to Jim Fleming and Eric Hochberg for suggestions and help in doing field work.

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“…Categorical definitions based on a location's biological or physical properties are frequently used in the published literature, but may be subject to idiosyncrasies of the researcher (Lindegarth and Gamfeldt 2005). One common quantitative approach is based on the measurement of dissolution of plaster, but its interpretation is complicated by differences in temperature and other conditions among sites (Muus 1968, Doty 1971, Porter et al 2000. A number of techniques for quantifying maximum wave force exist (Denny 1985, Bell andDenny 1994); however, the relationship between wave force and changes to immersion/emersion patterns is unknown.…”

Section: Discussion and Recommendationsmentioning

confidence: 99%

Evaluation of effective shore level as a method of characterizing intertidal wave exposure regimes

Gilman

Harley

Strickland

et al. 2006

Limnology & Ocean Methods

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Wave splash modifies the duration and timing of aerial exposure of intertidal organisms, influencing patterns of vertical zonation, thermal stress, and the consequences of climate change. Harley and Helmuth (Limnol. Oceanogr. 48:1498-1508) described a method for measuring effective shore level (ESL), a metric that combines the influence of wave splash and tidal regime on patterns of emersion and immersion. They identified immersion events as sharp drops in temperature recorded by submersible dataloggers and compared the tide height at the time of the temperature drop to the wave height recorded by an offshore buoy. Here we explore the generality of this method at 10 sites along the Pacific coast of North America spanning 14°of latitude. We deployed miniature temperature loggers at fixed intertidal heights at each site and recorded temperatures at intervals of 5 to 15 min for periods of up to 5 years. We use these data to explore the effects of different approaches to calculating temperature drops and wave heights, as well as variation in the buoy location, on ESL calculations. We present a software program (SiteParser) that can be used to identify temperature drops in a datalogger time series and also calculate daily and monthly summary statistics of temperature. We show that ESL parameters provide a useful metric for comparing the effects of wave action on immersion patterns within sites. We also introduce a metric of average wave run-up that can be used to compare the effect of wave action on immersion patterns among more distant locations.

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

Cited by 104 publications

References 78 publications

Nutrient loading and consumers: Agents of change in open-coast macrophyte assemblages

Nutrient loading and consumers: Agents of change in open-coast macrophyte assemblages

Effects of surface roughness and oscillatory flow on the dissolution of plaster forms: Evidence for nutrient mass transfer to coral reef communities

Evaluation of effective shore level as a method of characterizing intertidal wave exposure regimes

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