Jose Lucas Perez Llorens - Academia.edu (original) (raw)

Papers by Jose Lucas Perez Llorens

Research paper thumbnail of Effect of marine heat waves on carbon metabolism, optical characterization, and bioavailability of dissolved organic carbon in coastal vegetated communities

Limnology and Oceanography

Dissolved organic carbon (DOC) plays an essential role in the global marine carbon cycle, with co... more Dissolved organic carbon (DOC) plays an essential role in the global marine carbon cycle, with coastal vegetated communities as important DOC producers. However, the ultimate fate of this DOC remains still largely unknown due to the lack of knowledge about its chemical composition and lability. Furthermore, global change could alter both DOC fluxes and its bioavailability, affecting the carbon sequestration capacity of coastal vegetated communities. This study explores, in two contrasting seasons (winter and summer), the effects of an in situ simulated marine heatwave on carbon metabolism and DOC fluxes produced by seagrass (Cymodocea nodosa) and macroalgae (Caulerpa prolifera) communities. In addition, the fluorescent characteristics and biodegradability of the dissolved organic matter released directly by the communities under such conditions are evaluated. Under marine heatwave conditions, a significant increase in net community production (NCP) in C. nodosa and a shift to negati...

Research paper thumbnail of Taxonomic list of epiphytic macroalgae and host of Cuba

The following set of data provides the systematic list of epiphytic and host macroalgae reported ... more The following set of data provides the systematic list of epiphytic and host macroalgae reported in the scientific literature until 2019. Information is provided on the distribution and type of habitats where epiphytic macroalgae have been registered in Cuba. Finally, the richness of epiphytic macroalgae species per host is offered.

Research paper thumbnail of Seafood in Mediterranean countries: A culinary journey through history

International Journal of Gastronomy and Food Science, 2021

Research paper thumbnail of Those Curious and Delicious Seaweeds

Editorial UCA eBooks, 2018

Research paper thumbnail of Nueva guía visual de la fauna y flora marina del intermareal de La Caleta y roquedos intermareales asociados

Universidad de Cádiz, Jun 15, 2021

Nueva guía visual de las especies de animales (54 especies) y macroalgas (52 especies) más habitu... more Nueva guía visual de las especies de animales (54 especies) y macroalgas (52 especies) más habituales y/o curiosas de los roquedos del intermareal de La Caleta (Cádiz) y roquedos intermareales asociados. Se incluyen mas del doble de las especies que aparecían en la guía publicada en 2019. Dos de las especies de animales añadidas fueron recientemente descritas como nuevas para la Ciencia a partir de material encontrado en La Caleta (en parte).Universidad de Cádiz Ministerio de Ciencia e Innovación Fundación Española de Ciencia y Tecnología (FECYT) Campus de Excelencia Internacional del MAR (CEIMAR)108 pagina

Research paper thumbnail of Guía visual de la fauna y flora marina del intermareal de La Caleta y roquedos intermareales asociados

esponjas de esta especie, que tienen forma de riñón, pueden alcanzar los 40 cm de longitud, y sue... more esponjas de esta especie, que tienen forma de riñón, pueden alcanzar los 40 cm de longitud, y suelen vivir agrupadas muy cerca unas de otras. Esta especie no tiene ni espículas ni fibras de espongina, las fibras de colágeno hacen las funciones de esqueleto. Su coloración que varía en función de la luminosidad, puede ser parda o violeta. Su reproducción puede ser sexual (liberando espermatozoides al agua que fecundan el ovulo y se transforma en una larva ciliada que es liberada al agua) o asexual (por separación de fragmentos de la esponja). En zonas umbrías y cuevas a partir de unos 3 m. de profundidad hasta aproximadamente 30 metros de profundidad.

Research paper thumbnail of Técnicas para la estimación de variables de interés en el análisis del estado ecológico de las praderas de angiospermas marinas

Este documento representa una herramienta de diagnóstico simplificada del estado de salud de las ... more Este documento representa una herramienta de diagnóstico simplificada del estado de salud de las praderas de fanerógamas marinas, con el estudio de una serie de indicadores biológicos que permitan dicha estimación. Por tanto, este documento sirve de guía para decidir qué ...

Research paper thumbnail of The role of bio-hydrodynamic interactions in determining the functioning of shallow, benthic ecosystems

Epi-benthic organisms play a strong role in controlling pelagic-benthic mass transfer rates by di... more Epi-benthic organisms play a strong role in controlling pelagic-benthic mass transfer rates by directly modifying concentration gradients (ie, production, or removal of material) and by indirectly modifying near-bed hydrodynamics. Focusing on these bio-hydrodynamic interactions, ...

Research paper thumbnail of Those curious and delicious seaweeds: a fascinating voyage from biology to gastronomy

Research paper thumbnail of Los programas marinos de IGBP: Globec-Imber-Solasloicz

Research paper thumbnail of Seaweeds in mythology, folklore, poetry, and life

Journal of Applied Phycology, 2020

Seaweeds have been around since well before the dawn of mankind and have had varying degrees of i... more Seaweeds have been around since well before the dawn of mankind and have had varying degrees of influence on societies throughout history. Today, they have a well-established position of value after much scientific endeavour and commercialisation of applications. In the distant past, however, seaweeds were seen as a fundamental component of the sea and the beings associated with it, and they also held an essential connection to the land and the people who dwelt there. In the absence of science, myths and legends typically prevailed, and in the case of seaweed science today, many kernels of truth have now been exposed. This review traces myths and legends and some poetry which has been influenced by macroalgae over the ages, and it describes some of the early uses of seaweeds by humankind across the globe. With such a prominent role in the minds and imaginations of story tellers, artists, musicians, and poets, seaweeds command a position of respect in the evolution of ecological goods and services. While not strictly scientific, the information reviewed and laid out in this article underpins some of those uses of seaweeds that have now been established following thorough evidence-based research. Such research leads to a myriad of values of the goods and services rendered by seaweeds and their extracts, providing significant benefits to mankind, both currently, and into the future. Seaweeds were around well before the Anthropocene and are very likely to survive and contribute to global survival much longer than this current epoch.

Research paper thumbnail of Effects of light and biomass partitioning on growth, photosynthesis and carbohydrate content of the seagrass Zostera noltii Hornem

Journal of Experimental Marine Biology and Ecology, 2007

Plants of the seagrass Zostera noltii were cultured in the laboratory (mesocosms) for two weeks t... more Plants of the seagrass Zostera noltii were cultured in the laboratory (mesocosms) for two weeks to assess the effect of above: below-ground (AG/BG) biomass ratios and light on growth, photosynthesis and chemical composition. Experimental plant units (EPUs) with different proportions between AG and BG biomass were obtained from plants of the same size (containing 6 shoots and 5 internodes) by excising 0-5 shoots. The EPUs maintained the proportions in AG/BG biomass ratios during the experiment. While growth rate was unaffected by biomass partitioning at high light, maximum growth at low light was recorded in plants with low AG/BG ratios. The production of shoots and rhizomes showed a compensatory morphological response depending on the initial AG/BG proportions regardless of the light level. While shoot production, estimated as shoot appearance rate, was high at low AG/BG ratios and minimal under high AG/BG values, rhizome production, estimated as internode appearance rate and internode elongation rate, was maximal under high AG/BG proportions and decreased towards lower AG/BG ratios. This rhizomatic response was observed for secondary rhizomes and not for primary ones. In contrast to morphological response, no significant differences were detected in maximum electron transport rates (ETRm) among the different shoots in the plant. However, mean values of ETRm in plants were affected by biomass partitioning and light. EPUs grown in low light increased the sucrose stored in shoots as the AG/BG biomass ratios decreased; however, EPUs grown at high light showed no effect of biomass partitioning on sucrose levels. In conclusion, shoots excision by experimental manipulation caused a compensatory morphological response in plants while photosynthetic performance remained almost unaffected.

Research paper thumbnail of Effects of light availability on growth, architecture and nutrient content of the seagrass Zostera noltii Hornem

Journal of Experimental Marine Biology and Ecology, 2002

The growth vs. irradiance response of the seagrass Zostera noltii from Cadiz Bay Natural Park (so... more The growth vs. irradiance response of the seagrass Zostera noltii from Cadiz Bay Natural Park (southwestern Spain) was characterised. Plants were exposed along 14 days to different light treatments (1%, 7%, 42% and 100% surface irradiance, SI), using shade screens in an outdoor mesocosm. Growth at 100% SI (1.6 mg DW plant À 1 day À 1) was lower than that at 42% SI (2.4 mg DW plant À 1 day À 1), suggesting photoinhibition. The minimum light requirement estimated was 0.8 mol photons m À 2 day À 1 (2% SI). Light availability affected the pattern of plant development and the overall plant growth. The contribution of the apical shoots to the aboveground production was nearly constant (c.a. 1.13 cm plant À 1 day À 1) regardless of the light level (except at 1% SI). In contrast, recruitment and growth of lateral shoots arising from the main rhizome axes accounted for the observed differences in aboveground growth. Rhizome branching was only observed at 42% SI. The possibility of a light threshold for rhizome branching could explain the seasonality of shoot recruitment, as well as the observed decrease in shoot density along depth (or light) gradients in seagrass meadows. Carbon demands at low irradiances (1% and 7% SI) were partially met by mobilization of carbohydrate reserves (sucrose in belowground and starch in aboveground parts). Plant nitrogen content decreased with increasing light, especially in belowground parts, reaching critical levels for growth.

Research paper thumbnail of Effects of solar UV-B radiation on canopy structure of Ulva communities from southern Spain

Journal of Experimental Botany, 2002

Within the sheltered creeks of Ca  diz bay, Ulva thalli form extended mat-like canopies. The eff... more Within the sheltered creeks of Ca  diz bay, Ulva thalli form extended mat-like canopies. The effect of solar ultraviolet radiation on photosynthetic activity, the composition of photosynthetic and xanthophyll cycle pigments, and the amount of RubisCO, chaperonin 60 (CPN 60), and the induction of DNA damage in Ulva aff. rotundata Bliding from southern Spain was assessed in the ®eld. Samples collected from the natural community were covered by screening ®lters, generating different radiation conditions. During daily cycles, individual thalli showed photoinhibitory effects of the natural solar radiation. This inhibition was even more pronounced in samples only exposed to photosynthetically active radiation (PAR). Strongly increased heat dissipation in these samples indicated the activity of regulatory mechanisms involved in dynamic photoinhibition. Adverse effects of UV-B radiation on photosynthesis were only observed in combination with high levels of PAR, indicating the synergistic effects of the two wavelength ranges. In samples exposed either to PAR+UV-A or to UV-B+UV-A without PAR, no inhibition of photosynthetic quantum yield was found in the course of the day. At the natural site, the top layer of the mat-like canopies is generally completely bleached. Arti®cially designed Ulva canopies exhibited fast bleaching of the top layer under the natural solar radiation conditions, while this was not observed in canopies either shielded from UV or from PAR. The bleached ®rst layer of the canopies acts as a selective UV-B ®lter, and thus prevents subcanopy thalli from exposure to harmful radiation. This was con®rmed by the differences in photosynthetic activity, pigment composition, and the concentration of RubisCO in thalli with different positions within the canopy. In addition, the induction of the stress protein CPN 60 under UV exposure and the low accumulation of DNA damage indicate the presence of physiological protection mechanisms against harmful UV-B. A mechanism of UV-B-induced inhibition of photosynthesis under ®eld conditions is proposed.

Research paper thumbnail of Integrated outdoor culture of two estuarine macroalgae as biofilters for dissolved nutrients from Sparus auratus waste waters

Journal of Applied Phycology, 2005

Page 1. Journal of Applied Phycology (2005) 17: 557–567 DOI: 10.1007/s10811-005-9006-6 C Springer... more Page 1. Journal of Applied Phycology (2005) 17: 557–567 DOI: 10.1007/s10811-005-9006-6 C Springer 2005 Integrated outdoor culture of two estuarine macroalgae as biofilters for dissolved nutrients from Sparus aurata waste waters ...

Research paper thumbnail of Short-term phosphate uptake kinetics in Zostera noltii Hornem: a comparison between excised leaves and sediment-rooted plants

Hydrobiologia, 1995

Short-term phosphate uptake by excised leaves of Zostera noltii Hornem. as well as by leaves of s... more Short-term phosphate uptake by excised leaves of Zostera noltii Hornem. as well as by leaves of sediment-rooted plants were characterized and compared in a kinetic framework. Time courses of phosphate disappearance were measured over a wide range of initial substrate concentrations. Phosphate uptake determined by this perturbation method did not follow Michaelis-Menten kinetics. Both excised leaves and sediment-rooted plants exhibited a biphasic uptake pattern as a function of phosphate concentration. However, rooted plants showed higher uptake rates and accumulated higher amounts of phosphate than excised leaves. The results point out the importance of the structural and functional coupling between shoots and underground parts during the nutrient foliar uptake processes. Our study also indicates that Zostera noltii leaves function as a phosphate sink in the water column. A second objective of this work is to compare the perturbation and the multiple flask methods in determining the uptake kinetic parameters. The obtained results support that both methods provide valuable and complementary information in determining the uptake rates .

Research paper thumbnail of Temperature and emergence effects on the net photosynthesis of two Zostera noltii Hornem. morphotypes

Hydrobiologia, 1993

Apparent photosynthetic rates (APS) of two Zostera noltii Hornem. morphotypes were measured in ai... more Apparent photosynthetic rates (APS) of two Zostera noltii Hornem. morphotypes were measured in air and in water at different temperatures with a closed infra-red gas analysis system (IRGA). Hyperbolic functions accurately described the photosynthesis-CO, relationships when the leaves were exposed to air. The photosynthetic behaviour in water, on the contrary, could not be described by Michaelis type kinetics, due to the existence of a rapid transition from the initial slope to the saturation phase. Both morphotypes (narrow-leaved, NLM and large-leaved, LLM) showed higher APS rates in water than in air, although the highest APS rates, in air as well in water, were recorded for the NLM. Temperature had a significant influence on the photosynthetic parameters: APS,,, (maximum photosynthetic rate) decreased (in air and in water) with increased temperature in both morphotypes; compensation points (CP) in air increased at high temperature, especially in the LLM. NLM specimens showed enhanced affinity (lower Km) with increasing temperature in air. On the contrary, Km values in water were not significantly affected by temperature. The results suggest that NLM specimens are better adapted than the LLM to occur exposed to air. The distributional pattern of the two morphotypes in the Palmones Estuary is discussed on the basis of their photosynthetic behaviour.

Research paper thumbnail of Interactions of light and organic matter under contrasting resource simulated environments: the importance of clonal traits in the seagrass Zostera noltii

Hydrobiologia, 2009

Light reduction in the water column and enhanced organic matter (OM) load into the sediments are ... more Light reduction in the water column and enhanced organic matter (OM) load into the sediments are two main consequences of eutrophication in marine coastal areas. This study addresses the combined effects of light, OM, and clonal traits in the seagrass Zostera noltii. Large Z. noltii plants were grown in sand with or without the addition of OM and under two light levels (high light and low light). Whereas some complete plant replicates were grown under homogeneous light and/or OM conditions, other replicates were grown under contrasting light and/or OM levels between the apical and the distal parts of the same plant. The three-way factorial design (light, OM load, and apex position) allowed us to determine the harmful effect of light reduction and OM enrichment on the growth, photosynthetic performance, and biochemical composition of Z. noltii. The addition of OM to the sediment promoted a decrease, or even an inhibition, in net plant growth regardless of the light level when the whole plants were grown under homogeneous light conditions. However, the results differed when plants were grown under contrasting light and/or OM conditions between apical and distal parts. In this case, the harmful effect of OM load was alleviated when apical parts were grown under high light conditions. OM loads also negatively affected the photosynthetic performance, evaluated as leaf fluorescence. The results indicate the importance of clonal traits in the response of Z. noltii growth to light conditions and OM enrichment.

Research paper thumbnail of Shoot organization in the seagrass zostera noltii: implications for space occupation and plant architecture

Helgoland Marine Research, 2006

The growth pattern of the seagrass Zostera noltii is described through the analysis of the shoot ... more The growth pattern of the seagrass Zostera noltii is described through the analysis of the shoot primordium organization within different shoot types using optical and scanning electron microscopy. Both histological approaches showed that Z. noltii shoots are organized by a successive repetition of a unit named ''phytomer'' (shoot primordium, node, internode, root, sheath and leaf), in resemblance with the shoot structure described for land grasses. This study showed that differences among shoot types are determined by two factors: (1) the presence or absence of some of the fundamental parts (mainly shoot primordium) in the ''phytomer'', (2) the evolvement stage of these elements. The branching of Z. noltii was limited by shoot structure and shoot primordium arrangement; in the ''natural'' branching pattern the first axillary shoot branched opposite to the previous branch. Simulation of the topology of a Z. noltii plant using the ''natural'' branching pattern, and its opposite one, with two different branching angles for each pattern, showed that the reduction in the branching angle notably decreases the colonizing efficiency (ca. 25% from 90 to 45°). Changes in the timing of shoot primordium development and/or release, and the optimization of the branching angle in response to external forcing (light, nutrients, density, etc.) may elucidate species-specific differences and colonization strategies with respect to abiotic conditions.

Research paper thumbnail of Growth, carbon allocation and proteolytic activity in the seagrass Zostera noltii shaded by Ulva canopies

Functional Plant Biology, 2003

The effects of light reduction [100%, 25%, 10% and 1% mean daily-integrated photon irradiance (I0... more The effects of light reduction [100%, 25%, 10% and 1% mean daily-integrated photon irradiance (I0)] by Ulva rigida C. Agardh canopies on carbon balance, sugar-related enzymes and proteolytic activities of the seagrass Zostera noltii Hornem. were investigated. Shaded plants showed negative net growth and starch was mobilized in both above- and below-ground tissues. Sucrose declined in below-ground parts under severe light deprivation (10% and 1% I0), but was accumulated in above-ground parts. Mobilization of the non-structural carbohydrates (sucrose and starch) was explained by changes in activities of sucrose synthase (SuSy, EC 2.4.1.13) and sucrose-phosphate synthase (SPS, EC 2.4.2.24). Under severe light reduction, the capacity of above-ground tissues for sucrose formation and export declined, indicated by the lowest SPS activity. In contrast, severe light reduction increased the 'sink strength' of below-ground tissues, demonstrated by the highest SuSy activities, and dimi...

Research paper thumbnail of Effect of marine heat waves on carbon metabolism, optical characterization, and bioavailability of dissolved organic carbon in coastal vegetated communities

Limnology and Oceanography

Dissolved organic carbon (DOC) plays an essential role in the global marine carbon cycle, with co... more Dissolved organic carbon (DOC) plays an essential role in the global marine carbon cycle, with coastal vegetated communities as important DOC producers. However, the ultimate fate of this DOC remains still largely unknown due to the lack of knowledge about its chemical composition and lability. Furthermore, global change could alter both DOC fluxes and its bioavailability, affecting the carbon sequestration capacity of coastal vegetated communities. This study explores, in two contrasting seasons (winter and summer), the effects of an in situ simulated marine heatwave on carbon metabolism and DOC fluxes produced by seagrass (Cymodocea nodosa) and macroalgae (Caulerpa prolifera) communities. In addition, the fluorescent characteristics and biodegradability of the dissolved organic matter released directly by the communities under such conditions are evaluated. Under marine heatwave conditions, a significant increase in net community production (NCP) in C. nodosa and a shift to negati...

Research paper thumbnail of Taxonomic list of epiphytic macroalgae and host of Cuba

The following set of data provides the systematic list of epiphytic and host macroalgae reported ... more The following set of data provides the systematic list of epiphytic and host macroalgae reported in the scientific literature until 2019. Information is provided on the distribution and type of habitats where epiphytic macroalgae have been registered in Cuba. Finally, the richness of epiphytic macroalgae species per host is offered.

Research paper thumbnail of Seafood in Mediterranean countries: A culinary journey through history

International Journal of Gastronomy and Food Science, 2021

Research paper thumbnail of Those Curious and Delicious Seaweeds

Editorial UCA eBooks, 2018

Research paper thumbnail of Nueva guía visual de la fauna y flora marina del intermareal de La Caleta y roquedos intermareales asociados

Universidad de Cádiz, Jun 15, 2021

Nueva guía visual de las especies de animales (54 especies) y macroalgas (52 especies) más habitu... more Nueva guía visual de las especies de animales (54 especies) y macroalgas (52 especies) más habituales y/o curiosas de los roquedos del intermareal de La Caleta (Cádiz) y roquedos intermareales asociados. Se incluyen mas del doble de las especies que aparecían en la guía publicada en 2019. Dos de las especies de animales añadidas fueron recientemente descritas como nuevas para la Ciencia a partir de material encontrado en La Caleta (en parte).Universidad de Cádiz Ministerio de Ciencia e Innovación Fundación Española de Ciencia y Tecnología (FECYT) Campus de Excelencia Internacional del MAR (CEIMAR)108 pagina

Research paper thumbnail of Guía visual de la fauna y flora marina del intermareal de La Caleta y roquedos intermareales asociados

esponjas de esta especie, que tienen forma de riñón, pueden alcanzar los 40 cm de longitud, y sue... more esponjas de esta especie, que tienen forma de riñón, pueden alcanzar los 40 cm de longitud, y suelen vivir agrupadas muy cerca unas de otras. Esta especie no tiene ni espículas ni fibras de espongina, las fibras de colágeno hacen las funciones de esqueleto. Su coloración que varía en función de la luminosidad, puede ser parda o violeta. Su reproducción puede ser sexual (liberando espermatozoides al agua que fecundan el ovulo y se transforma en una larva ciliada que es liberada al agua) o asexual (por separación de fragmentos de la esponja). En zonas umbrías y cuevas a partir de unos 3 m. de profundidad hasta aproximadamente 30 metros de profundidad.

Research paper thumbnail of Técnicas para la estimación de variables de interés en el análisis del estado ecológico de las praderas de angiospermas marinas

Este documento representa una herramienta de diagnóstico simplificada del estado de salud de las ... more Este documento representa una herramienta de diagnóstico simplificada del estado de salud de las praderas de fanerógamas marinas, con el estudio de una serie de indicadores biológicos que permitan dicha estimación. Por tanto, este documento sirve de guía para decidir qué ...

Research paper thumbnail of The role of bio-hydrodynamic interactions in determining the functioning of shallow, benthic ecosystems

Epi-benthic organisms play a strong role in controlling pelagic-benthic mass transfer rates by di... more Epi-benthic organisms play a strong role in controlling pelagic-benthic mass transfer rates by directly modifying concentration gradients (ie, production, or removal of material) and by indirectly modifying near-bed hydrodynamics. Focusing on these bio-hydrodynamic interactions, ...

Research paper thumbnail of Those curious and delicious seaweeds: a fascinating voyage from biology to gastronomy

Research paper thumbnail of Los programas marinos de IGBP: Globec-Imber-Solasloicz

Research paper thumbnail of Seaweeds in mythology, folklore, poetry, and life

Journal of Applied Phycology, 2020

Seaweeds have been around since well before the dawn of mankind and have had varying degrees of i... more Seaweeds have been around since well before the dawn of mankind and have had varying degrees of influence on societies throughout history. Today, they have a well-established position of value after much scientific endeavour and commercialisation of applications. In the distant past, however, seaweeds were seen as a fundamental component of the sea and the beings associated with it, and they also held an essential connection to the land and the people who dwelt there. In the absence of science, myths and legends typically prevailed, and in the case of seaweed science today, many kernels of truth have now been exposed. This review traces myths and legends and some poetry which has been influenced by macroalgae over the ages, and it describes some of the early uses of seaweeds by humankind across the globe. With such a prominent role in the minds and imaginations of story tellers, artists, musicians, and poets, seaweeds command a position of respect in the evolution of ecological goods and services. While not strictly scientific, the information reviewed and laid out in this article underpins some of those uses of seaweeds that have now been established following thorough evidence-based research. Such research leads to a myriad of values of the goods and services rendered by seaweeds and their extracts, providing significant benefits to mankind, both currently, and into the future. Seaweeds were around well before the Anthropocene and are very likely to survive and contribute to global survival much longer than this current epoch.

Research paper thumbnail of Effects of light and biomass partitioning on growth, photosynthesis and carbohydrate content of the seagrass Zostera noltii Hornem

Journal of Experimental Marine Biology and Ecology, 2007

Plants of the seagrass Zostera noltii were cultured in the laboratory (mesocosms) for two weeks t... more Plants of the seagrass Zostera noltii were cultured in the laboratory (mesocosms) for two weeks to assess the effect of above: below-ground (AG/BG) biomass ratios and light on growth, photosynthesis and chemical composition. Experimental plant units (EPUs) with different proportions between AG and BG biomass were obtained from plants of the same size (containing 6 shoots and 5 internodes) by excising 0-5 shoots. The EPUs maintained the proportions in AG/BG biomass ratios during the experiment. While growth rate was unaffected by biomass partitioning at high light, maximum growth at low light was recorded in plants with low AG/BG ratios. The production of shoots and rhizomes showed a compensatory morphological response depending on the initial AG/BG proportions regardless of the light level. While shoot production, estimated as shoot appearance rate, was high at low AG/BG ratios and minimal under high AG/BG values, rhizome production, estimated as internode appearance rate and internode elongation rate, was maximal under high AG/BG proportions and decreased towards lower AG/BG ratios. This rhizomatic response was observed for secondary rhizomes and not for primary ones. In contrast to morphological response, no significant differences were detected in maximum electron transport rates (ETRm) among the different shoots in the plant. However, mean values of ETRm in plants were affected by biomass partitioning and light. EPUs grown in low light increased the sucrose stored in shoots as the AG/BG biomass ratios decreased; however, EPUs grown at high light showed no effect of biomass partitioning on sucrose levels. In conclusion, shoots excision by experimental manipulation caused a compensatory morphological response in plants while photosynthetic performance remained almost unaffected.

Research paper thumbnail of Effects of light availability on growth, architecture and nutrient content of the seagrass Zostera noltii Hornem

Journal of Experimental Marine Biology and Ecology, 2002

The growth vs. irradiance response of the seagrass Zostera noltii from Cadiz Bay Natural Park (so... more The growth vs. irradiance response of the seagrass Zostera noltii from Cadiz Bay Natural Park (southwestern Spain) was characterised. Plants were exposed along 14 days to different light treatments (1%, 7%, 42% and 100% surface irradiance, SI), using shade screens in an outdoor mesocosm. Growth at 100% SI (1.6 mg DW plant À 1 day À 1) was lower than that at 42% SI (2.4 mg DW plant À 1 day À 1), suggesting photoinhibition. The minimum light requirement estimated was 0.8 mol photons m À 2 day À 1 (2% SI). Light availability affected the pattern of plant development and the overall plant growth. The contribution of the apical shoots to the aboveground production was nearly constant (c.a. 1.13 cm plant À 1 day À 1) regardless of the light level (except at 1% SI). In contrast, recruitment and growth of lateral shoots arising from the main rhizome axes accounted for the observed differences in aboveground growth. Rhizome branching was only observed at 42% SI. The possibility of a light threshold for rhizome branching could explain the seasonality of shoot recruitment, as well as the observed decrease in shoot density along depth (or light) gradients in seagrass meadows. Carbon demands at low irradiances (1% and 7% SI) were partially met by mobilization of carbohydrate reserves (sucrose in belowground and starch in aboveground parts). Plant nitrogen content decreased with increasing light, especially in belowground parts, reaching critical levels for growth.

Research paper thumbnail of Effects of solar UV-B radiation on canopy structure of Ulva communities from southern Spain

Journal of Experimental Botany, 2002

Within the sheltered creeks of Ca  diz bay, Ulva thalli form extended mat-like canopies. The eff... more Within the sheltered creeks of Ca  diz bay, Ulva thalli form extended mat-like canopies. The effect of solar ultraviolet radiation on photosynthetic activity, the composition of photosynthetic and xanthophyll cycle pigments, and the amount of RubisCO, chaperonin 60 (CPN 60), and the induction of DNA damage in Ulva aff. rotundata Bliding from southern Spain was assessed in the ®eld. Samples collected from the natural community were covered by screening ®lters, generating different radiation conditions. During daily cycles, individual thalli showed photoinhibitory effects of the natural solar radiation. This inhibition was even more pronounced in samples only exposed to photosynthetically active radiation (PAR). Strongly increased heat dissipation in these samples indicated the activity of regulatory mechanisms involved in dynamic photoinhibition. Adverse effects of UV-B radiation on photosynthesis were only observed in combination with high levels of PAR, indicating the synergistic effects of the two wavelength ranges. In samples exposed either to PAR+UV-A or to UV-B+UV-A without PAR, no inhibition of photosynthetic quantum yield was found in the course of the day. At the natural site, the top layer of the mat-like canopies is generally completely bleached. Arti®cially designed Ulva canopies exhibited fast bleaching of the top layer under the natural solar radiation conditions, while this was not observed in canopies either shielded from UV or from PAR. The bleached ®rst layer of the canopies acts as a selective UV-B ®lter, and thus prevents subcanopy thalli from exposure to harmful radiation. This was con®rmed by the differences in photosynthetic activity, pigment composition, and the concentration of RubisCO in thalli with different positions within the canopy. In addition, the induction of the stress protein CPN 60 under UV exposure and the low accumulation of DNA damage indicate the presence of physiological protection mechanisms against harmful UV-B. A mechanism of UV-B-induced inhibition of photosynthesis under ®eld conditions is proposed.

Research paper thumbnail of Integrated outdoor culture of two estuarine macroalgae as biofilters for dissolved nutrients from Sparus auratus waste waters

Journal of Applied Phycology, 2005

Page 1. Journal of Applied Phycology (2005) 17: 557–567 DOI: 10.1007/s10811-005-9006-6 C Springer... more Page 1. Journal of Applied Phycology (2005) 17: 557–567 DOI: 10.1007/s10811-005-9006-6 C Springer 2005 Integrated outdoor culture of two estuarine macroalgae as biofilters for dissolved nutrients from Sparus aurata waste waters ...

Research paper thumbnail of Short-term phosphate uptake kinetics in Zostera noltii Hornem: a comparison between excised leaves and sediment-rooted plants

Hydrobiologia, 1995

Short-term phosphate uptake by excised leaves of Zostera noltii Hornem. as well as by leaves of s... more Short-term phosphate uptake by excised leaves of Zostera noltii Hornem. as well as by leaves of sediment-rooted plants were characterized and compared in a kinetic framework. Time courses of phosphate disappearance were measured over a wide range of initial substrate concentrations. Phosphate uptake determined by this perturbation method did not follow Michaelis-Menten kinetics. Both excised leaves and sediment-rooted plants exhibited a biphasic uptake pattern as a function of phosphate concentration. However, rooted plants showed higher uptake rates and accumulated higher amounts of phosphate than excised leaves. The results point out the importance of the structural and functional coupling between shoots and underground parts during the nutrient foliar uptake processes. Our study also indicates that Zostera noltii leaves function as a phosphate sink in the water column. A second objective of this work is to compare the perturbation and the multiple flask methods in determining the uptake kinetic parameters. The obtained results support that both methods provide valuable and complementary information in determining the uptake rates .

Research paper thumbnail of Temperature and emergence effects on the net photosynthesis of two Zostera noltii Hornem. morphotypes

Hydrobiologia, 1993

Apparent photosynthetic rates (APS) of two Zostera noltii Hornem. morphotypes were measured in ai... more Apparent photosynthetic rates (APS) of two Zostera noltii Hornem. morphotypes were measured in air and in water at different temperatures with a closed infra-red gas analysis system (IRGA). Hyperbolic functions accurately described the photosynthesis-CO, relationships when the leaves were exposed to air. The photosynthetic behaviour in water, on the contrary, could not be described by Michaelis type kinetics, due to the existence of a rapid transition from the initial slope to the saturation phase. Both morphotypes (narrow-leaved, NLM and large-leaved, LLM) showed higher APS rates in water than in air, although the highest APS rates, in air as well in water, were recorded for the NLM. Temperature had a significant influence on the photosynthetic parameters: APS,,, (maximum photosynthetic rate) decreased (in air and in water) with increased temperature in both morphotypes; compensation points (CP) in air increased at high temperature, especially in the LLM. NLM specimens showed enhanced affinity (lower Km) with increasing temperature in air. On the contrary, Km values in water were not significantly affected by temperature. The results suggest that NLM specimens are better adapted than the LLM to occur exposed to air. The distributional pattern of the two morphotypes in the Palmones Estuary is discussed on the basis of their photosynthetic behaviour.

Research paper thumbnail of Interactions of light and organic matter under contrasting resource simulated environments: the importance of clonal traits in the seagrass Zostera noltii

Hydrobiologia, 2009

Light reduction in the water column and enhanced organic matter (OM) load into the sediments are ... more Light reduction in the water column and enhanced organic matter (OM) load into the sediments are two main consequences of eutrophication in marine coastal areas. This study addresses the combined effects of light, OM, and clonal traits in the seagrass Zostera noltii. Large Z. noltii plants were grown in sand with or without the addition of OM and under two light levels (high light and low light). Whereas some complete plant replicates were grown under homogeneous light and/or OM conditions, other replicates were grown under contrasting light and/or OM levels between the apical and the distal parts of the same plant. The three-way factorial design (light, OM load, and apex position) allowed us to determine the harmful effect of light reduction and OM enrichment on the growth, photosynthetic performance, and biochemical composition of Z. noltii. The addition of OM to the sediment promoted a decrease, or even an inhibition, in net plant growth regardless of the light level when the whole plants were grown under homogeneous light conditions. However, the results differed when plants were grown under contrasting light and/or OM conditions between apical and distal parts. In this case, the harmful effect of OM load was alleviated when apical parts were grown under high light conditions. OM loads also negatively affected the photosynthetic performance, evaluated as leaf fluorescence. The results indicate the importance of clonal traits in the response of Z. noltii growth to light conditions and OM enrichment.

Research paper thumbnail of Shoot organization in the seagrass zostera noltii: implications for space occupation and plant architecture

Helgoland Marine Research, 2006

The growth pattern of the seagrass Zostera noltii is described through the analysis of the shoot ... more The growth pattern of the seagrass Zostera noltii is described through the analysis of the shoot primordium organization within different shoot types using optical and scanning electron microscopy. Both histological approaches showed that Z. noltii shoots are organized by a successive repetition of a unit named ''phytomer'' (shoot primordium, node, internode, root, sheath and leaf), in resemblance with the shoot structure described for land grasses. This study showed that differences among shoot types are determined by two factors: (1) the presence or absence of some of the fundamental parts (mainly shoot primordium) in the ''phytomer'', (2) the evolvement stage of these elements. The branching of Z. noltii was limited by shoot structure and shoot primordium arrangement; in the ''natural'' branching pattern the first axillary shoot branched opposite to the previous branch. Simulation of the topology of a Z. noltii plant using the ''natural'' branching pattern, and its opposite one, with two different branching angles for each pattern, showed that the reduction in the branching angle notably decreases the colonizing efficiency (ca. 25% from 90 to 45°). Changes in the timing of shoot primordium development and/or release, and the optimization of the branching angle in response to external forcing (light, nutrients, density, etc.) may elucidate species-specific differences and colonization strategies with respect to abiotic conditions.

Research paper thumbnail of Growth, carbon allocation and proteolytic activity in the seagrass Zostera noltii shaded by Ulva canopies

Functional Plant Biology, 2003

The effects of light reduction [100%, 25%, 10% and 1% mean daily-integrated photon irradiance (I0... more The effects of light reduction [100%, 25%, 10% and 1% mean daily-integrated photon irradiance (I0)] by Ulva rigida C. Agardh canopies on carbon balance, sugar-related enzymes and proteolytic activities of the seagrass Zostera noltii Hornem. were investigated. Shaded plants showed negative net growth and starch was mobilized in both above- and below-ground tissues. Sucrose declined in below-ground parts under severe light deprivation (10% and 1% I0), but was accumulated in above-ground parts. Mobilization of the non-structural carbohydrates (sucrose and starch) was explained by changes in activities of sucrose synthase (SuSy, EC 2.4.1.13) and sucrose-phosphate synthase (SPS, EC 2.4.2.24). Under severe light reduction, the capacity of above-ground tissues for sucrose formation and export declined, indicated by the lowest SPS activity. In contrast, severe light reduction increased the 'sink strength' of below-ground tissues, demonstrated by the highest SuSy activities, and dimi...