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Daily variation patterns in seagrass photosynthesis along a vertical gradient

2003Journal article Open access
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dc.contributor.authorSilva, João
dc.contributor.authorSantos, Rui
dc.date.accessioned2018-12-07T14:58:39Z
dc.date.available2018-12-07T14:58:39Z
dc.date.issued2003
dc.description.abstractThe relationship between the available photosynthetic active radiation (PAR) and the photosynthetic yield of Photosystem II (PSII), measured by chlorophyll a fluorescence, was assessed in the intertidal seagrasses of Ria Formosa, a coastal lagoon in southern Portugal. Most of the lagoon's intertidal is occupied by a monospecific population of Zostera noltii (Hornemann), which occupies a vertical gradient of about 2 m. The upper distribution limit of this species comprises the edge of a Spartina maritima (Curtis) Fernald saltmarsh and the lower limit the transition to the subtidal, dominated by Cymodocea nodosa (Ucria) Ascherson. Diurnal changes in the pattern of rapid-light curves (RLCs) was investigated with pulse amplitude-modulated (PAM) fluorometry in Z. noltii and in C. nodosa in the upper and lower intertidal. The light reactions of photosynthesis were assessed by fitting photosynthesis-irradiance (P-I) models to the RLCs. The photosynthetic parameters of Z noltii revealed that this plant species exhibits sun- and shade-type responses in its upper and lower vertical distribution limits, respectively. At the lower distribution limit in low light, the initial slopes of all RLCs were significantly higher than at the upper site, but decreased with increasing irradiances, while at the upper distribution limit, although lower, the slopes were unaffected by increasing irradiance. C. nodosa presented a typical shade-type response, as evidenced by the daily variation and light dependence of both photosynthetic efficiency and optimal quantum yield. The relationship between the maximum electron-transport rate and irradiance suggests that this species is strongly light-limited. We suggest that attempts to characterize the photosynthetic behaviour of an intertidal meadow should consider both diurnal fluctuations in the plants' photosynthetic activity as well as its vertical distribution frequency.
dc.identifier.doi10.3354/meps257037
dc.identifier.issn0171-8630
dc.identifier.urihttp://hdl.handle.net/10400.1/12140
dc.language.isoeng
dc.peerreviewedyes
dc.publisherInter-Research
dc.subjectModulated pam fluorometry
dc.subjectSubmersed aquatic vegetation
dc.subjectMeasured In-Situ
dc.subjectChlorophyll fluorescence
dc.subjectThalassia-testudinum
dc.subjectCarbon assimilation
dc.subjectZostera-marina
dc.subjectQuantum yield
dc.subjectWater-quality
dc.subjectLight
dc.titleDaily variation patterns in seagrass photosynthesis along a vertical gradient
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage44
oaire.citation.startPage37
oaire.citation.titleMarine Ecology Progress Series
oaire.citation.volume257
person.familyNameSilva
person.familyNameSantos
person.givenNameJoão
person.givenNameRui
person.identifier82814
person.identifier42560
person.identifier.ciencia-id8216-527E-1BD4
person.identifier.ciencia-id9B18-444D-2244
person.identifier.orcid0000-0002-7211-1661
person.identifier.orcid0000-0002-7861-4366
person.identifier.ridJ-7874-2013
person.identifier.ridB-4168-2008
person.identifier.scopus-author-id7403023547
person.identifier.scopus-author-id7201375018
rcaap.rightsopenAccess
rcaap.typearticle
relation.isAuthorOfPublication61040b53-b17a-40f6-b42e-f5476a7a6ddb
relation.isAuthorOfPublication84487ca8-404a-4584-81f0-3662c340d712
relation.isAuthorOfPublication.latestForDiscovery61040b53-b17a-40f6-b42e-f5476a7a6ddb

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