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Abstract In order to study the spatial patterns of genetic diversity of a clonal marine angiosperm, the seagrass Cymodocea nodosa, microsatellite markers were obtained by screening a genomic library enriched for the (CT) dinucleotide motif. Of 38 primer pairs defined, 15 amplified polymorphic microsatellites and are described. These loci identified a number of alleles ranging from two to seven, and showed expected heterozygosity ranging from 0.35 to 0.76, when a group of 40 individuals from Cadiz Bay in Spain was analysed. Additionally, we describe here the multiplexing conditions for 12 of these loci.
Abstract The formation of nodes, stem elongation and the phenology of stunted Avicennia marina was examined in the Central Red Sea, where Avicennia marina is at the limit of its distribution range and submitted to extremely arid conditions with salinity above 38 psu and water temperature as high as 35° C. The annual node production was rather uniform among locations averaging 9.59 node y −1 , which resulted in a plastocron interval, the interval in between production of two consecutive nodes along a stem, of 38 days. However, the internodal length varied significantly between locations, resulting in growth differences possibly reflecting the environmental conditions of locations. The reproductive cycle lasted for approximately 12 months, and was characterized by peak flowering and propagule development in November and January. These phenological observations provide a starting point for research and restoration programs on the ecology of mangroves in the Central Red Sea, while the plastochrone index reported here would allow calculations of the growth and production of the species from simple morphological measurements.
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 194:283-294 (2000) - doi:10.3354/meps194283 Latitudinal variability in phosphate uptake in the Central Atlantic Mireia Cañellas*, Susana Agustí, Carlos M. Duarte** Instituto Mediterráneo de Estudios Avanzados (IMEDEA), CSIC-Universitat de Illes Balears, c/Miquel Marquès 21, 07190 Esporles (Illes Balears), Spain *Present address: Regidoria de Medi Ambient i Sostenibilitat, Ajuntament de Sabadell, C. del Sol 1-1, 08201 Sabadell, Spain **Corresponding author. E-mail: ieacdq@clust.uib.es ABSTRACT: The role of P in regulating planktonic production in Atlantic waters was assessed by the examination of the phosphate turnover time and uptake rate along a latitudinal transect across the Central Atlantic Ocean (27°N to 36°S). Phosphate uptake rates and the affinity for phosphate were higher for small (<0.8 µm) organisms, compared with those >0.8 µm. Phosphate uptake rates were relatively low, resulting in long phosphate turnover times (days), except in the surface waters south of 25°S, which were also characterized by the highest uptake rates and affinity for phosphate, and the smallest total P pools observed along the transect. The organisms were found to realize their maximal phosphate uptake rates at ambient phosphate concentrations, suggesting the adequacy of the P supply to support the requirements of organisms. These findings suggest that inorganic P was not limiting community production in most of the Central Atlantic, except for the area south of 25°S, where P uptake could possibly be limited by P supply. The long turnover times generally observed in the Central Atlantic Ocean are in agreement with previous observations in oceanic systems elsewhere, suggesting that the observation that P is unlikely to be a limiting resource for planktonic growth can be extrapolated to most of the open ocean. The combined rate of P excretion from planktonic organisms and their microbial grazers as dissolved organic phosphorus (DOP) represented 75% of the total phosphate uptake. This DOP does not reach a sufficient accumulation as to drive an important downward flux of DOP, which represents a loss of only 9% of the P inputs into the biogenic layer. Hence, the high P uptake rate of the planktonic community in the Central Atlantic provides P in excess to support primary production, leading to a release as DOP, which appears to be rapidly recycled in the biogenic layer, thereby maintaining an adequate P supply to fuel primary production. KEY WORDS: Phosphate · Uptake · Atlantic · Excretion · Turnover · Picoplankton · Microplankton Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 194. Publication date: March 17, 2000 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 2000 Inter-Research.
Abstract. Transparent exopolymer particles (TEP) are the most ubiquitous gel particles in the ocean and form abiotically from dissolved precursors. Although these particles can accumulate at the ocean surface, being thus exposed to intense sunlight, the role of solar radiation for the assembly and degradation of TEP is unknown. In this study, we experimentally determined the effects of visible and ultraviolet B (UVB) radiation on (1) TEP degradation (photolysis experiments), (2) TEP assembly from dissolved polymers (photoinhibition experiments) and (3) TEP release by microorganisms. Solar radiation, particularly in the UVB range, caused significant TEP photolysis, with loss rates from 27 to 34% per day. Dissolved polysaccharides did not increase in parallel. No TEP were formed under UVB, visible or dark conditions, indicating that light does not promote TEP assembly. UVB radiation enhanced TEP release by microorganisms, possibly due to cell deaths, or as a protective measure. Increases in UVB may lead to enhanced TEP photolysis in the ocean, with further consequences for TEP dynamics and, ultimately, sea-air gas exchange.
Datos tecnicos: 5 minutos, color, espanol. Ficha tecnica: Gabinete de Presidencia CSIC y Departamento de Comunicacion
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 158:103-110 (1997) - doi:10.3354/meps158103 Is the apical growth of Cymodocea nodosa dependent on clonal integration? J. Terrados1,*, C. M. Duarte1, W. J. Kenworthy2 1Centro de Estudios Avanzados de Blanes, CSIC, Camí de Santa Bárbara, s/n, E-17300 Blanes (Girona), Spain 2Beaufort Laboratory, Southeast Fisheries Science Center, National Marine Fisheries Service, NOAA, 101 Pivers Island Road, Beaufort, North Carolina 28516-9722, USA *E-mail: terrados@ceab.csic.es The importance of clonal integration for the production of biomass by the apical meristem of Cymodoceanodosa (Ucria) Ascherson was tested insitu by experimental manipulation. The production of new biomass by the apical meristem of a horizontal rhizome, as well as the leaf growth of the remaining shoots, was greatly reduced when the horizontal rhizome was severed, even when up to 11 shoots were left connected to the apical meristem of the rhizome. In contrast, the elimination of up to 8 shoots after the 3 apical shoots on a horizontal rhizome did not affect the production of biomass by the apical meristem. These results show that growth at the apical meristem of a C.nodosa rhizome depends on resources translocated along the rhizome from shoots situated further than 50 cm from the rhizome apex and that all the individual shoots (ramets) in a C.nodosa clone should be considered as one unit. Clonal integration does not depend on the presence of living shoots along the translocation route but is dependent on the integrity of the horizontal rhizome. Clonal integration · Growth · Seagrasses · Cymodoceanodosa Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 158. Publication date: November 17, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.
