pH gradients in the diffusive boundary layer of subarctic macrophytes

Handle URI:
http://hdl.handle.net/10754/625628
Title:
pH gradients in the diffusive boundary layer of subarctic macrophytes
Authors:
Hendriks, Iris E.; Duarte, Carlos M. ( 0000-0002-1213-1361 ) ; Marbà, Núria; Krause-Jensen, Dorte
Abstract:
Highly productive macrophytes produce diurnal and seasonal cycles in CO concentrations modulated by metabolic activity, which cause discrepancies between pH in the bulk water and near seaweed blades, especially when entering the diffusion boundary layer (DBL). Calcifying epiphytic organisms living in this environment are therefore exposed to a different pH environment than that of the water column. To evaluate the actual pH environment on blade surfaces, we measured the thickness of the DBL and pH gradients within it for six subarctic macrophytes: Fucus vesiculosus, Ascophyllum nodosum, Ulva lactuca, Zostera marina, Saccharina longicruris, and Agarum clathratum. We measured pH under laboratory conditions at ambient temperatures (2–3 °C) and slow, stable flow over the blade surface at five light intensities (dark, 30, 50, 100 and 200 µmol photons m s). Boundary layer thickness ranged between 511 and 1632 µm, while the maximum difference in pH (∆pH) between the blade surface and the water column ranged between 0.4 ± 0.14 (average ± SE; Zostera) and 1.2 ± 0.13 (average ± SE; Ulva) pH units. These differences in pH are larger than predictions for pH changes in the bulk water by the end of the century. A simple quadratic model best described the relationship between light intensity and maximum ∆pH, pointing at relatively low optimum PAR of between 28 and 139 µmol photons m s to reach maximum ∆pH. Elevated pH at the blade surface may provide chemical “refugia” for calcifying epiphytic organisms, especially during summer at higher latitudes where photoperiods are long.
KAUST Department:
Red Sea Research Center (RSRC)
Citation:
Hendriks IE, Duarte CM, Marbà N, Krause-Jensen D (2017) pH gradients in the diffusive boundary layer of subarctic macrophytes. Polar Biology. Available: http://dx.doi.org/10.1007/s00300-017-2143-y.
Publisher:
Springer Nature
Journal:
Polar Biology
Issue Date:
20-Jun-2017
DOI:
10.1007/s00300-017-2143-y
Type:
Article
ISSN:
0722-4060; 1432-2056
Sponsors:
This study was funded by the Danish Environmental Protection Agency within the Danish Cooperation for Environment in the Arctic (DANCEA).
Additional Links:
https://link.springer.com/article/10.1007%2Fs00300-017-2143-y
Appears in Collections:
Articles; Red Sea Research Center (RSRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorHendriks, Iris E.en
dc.contributor.authorDuarte, Carlos M.en
dc.contributor.authorMarbà, Núriaen
dc.contributor.authorKrause-Jensen, Dorteen
dc.date.accessioned2017-10-03T12:49:30Z-
dc.date.available2017-10-03T12:49:30Z-
dc.date.issued2017-06-20en
dc.identifier.citationHendriks IE, Duarte CM, Marbà N, Krause-Jensen D (2017) pH gradients in the diffusive boundary layer of subarctic macrophytes. Polar Biology. Available: http://dx.doi.org/10.1007/s00300-017-2143-y.en
dc.identifier.issn0722-4060en
dc.identifier.issn1432-2056en
dc.identifier.doi10.1007/s00300-017-2143-yen
dc.identifier.urihttp://hdl.handle.net/10754/625628-
dc.description.abstractHighly productive macrophytes produce diurnal and seasonal cycles in CO concentrations modulated by metabolic activity, which cause discrepancies between pH in the bulk water and near seaweed blades, especially when entering the diffusion boundary layer (DBL). Calcifying epiphytic organisms living in this environment are therefore exposed to a different pH environment than that of the water column. To evaluate the actual pH environment on blade surfaces, we measured the thickness of the DBL and pH gradients within it for six subarctic macrophytes: Fucus vesiculosus, Ascophyllum nodosum, Ulva lactuca, Zostera marina, Saccharina longicruris, and Agarum clathratum. We measured pH under laboratory conditions at ambient temperatures (2–3 °C) and slow, stable flow over the blade surface at five light intensities (dark, 30, 50, 100 and 200 µmol photons m s). Boundary layer thickness ranged between 511 and 1632 µm, while the maximum difference in pH (∆pH) between the blade surface and the water column ranged between 0.4 ± 0.14 (average ± SE; Zostera) and 1.2 ± 0.13 (average ± SE; Ulva) pH units. These differences in pH are larger than predictions for pH changes in the bulk water by the end of the century. A simple quadratic model best described the relationship between light intensity and maximum ∆pH, pointing at relatively low optimum PAR of between 28 and 139 µmol photons m s to reach maximum ∆pH. Elevated pH at the blade surface may provide chemical “refugia” for calcifying epiphytic organisms, especially during summer at higher latitudes where photoperiods are long.en
dc.description.sponsorshipThis study was funded by the Danish Environmental Protection Agency within the Danish Cooperation for Environment in the Arctic (DANCEA).en
dc.publisherSpringer Natureen
dc.relation.urlhttps://link.springer.com/article/10.1007%2Fs00300-017-2143-yen
dc.subjectDiffusive boundary layeren
dc.subjectpH gradientsen
dc.subjectSubarctic macrophytesen
dc.titlepH gradients in the diffusive boundary layer of subarctic macrophytesen
dc.typeArticleen
dc.contributor.departmentRed Sea Research Center (RSRC)en
dc.identifier.journalPolar Biologyen
dc.contributor.institutionDepartamento de Biología, Universitat de les Illes Balears, crta Valldemossa km 7.5, Palma De Mallorca, 07122, , Spainen
dc.contributor.institutionDepartment of Global Change Research, IMEDEA (CSIC-UIB) Instituto Mediterráneo de Estudios Avanzados, Miquel Marqués 21, Esporles, 07190, , Spainen
dc.contributor.institutionFaculty of Biosciences, Fisheries and Economics, University of Tromsø, Tromsø, , Norwayen
dc.contributor.institutionDepartment of Bioscience, Arhus University, Vejlsøvej 25, Silkeborg, 8600, , Denmarken
dc.contributor.institutionArctic Research Centre, Bioscience, Aarhus University, Ny Munkegade 114, Århus C, 8000, , Denmarken
kaust.authorDuarte, Carlos M.en
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