Publications

Density and distribution patterns of seafloor macrolitter in the eastern Red Sea

Depth-acclimation of photosynthesis, morphology and demography of Posidonia oceanica and Cymodocea nodosa in the Spanish Mediterranean Sea

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 236:89-97 (2002) - doi:10.3354/meps236089 Depth-acclimation of photosynthesis, morphology and demography of Posidonia oceanica and Cymodocea nodosa in the Spanish Mediterranean Sea Birgit Olesen1,*, Susana Enríquez2, Carlos M. Duarte3, Kaj Sand-Jensen4 1Department of Plant Ecology, University of Aarhus, Nordlandsvej 68, 8240 Riskov, Denmark 2Unidad Académia de Puerto Morelos, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Apto. Postal 1152, 77500 Cancún, Quintana Roo, Mexico 3Instituto Mediterráno de Estudios Avanzados (SCIC-UIB), Miquel Marqués 21, 07190 Esporles, Islas Baleares, Spain 4Freshwater Biological Laboratory, University of Copenhagen, 51 Helsingørsgade, 3400 Hillerød, Denmark *E-mail: birgit.olesen@biology.au.dk ABSTRACT: Depth-related changes in population structure, biomass partitioning and photosynthesis were studied in populations of Cymodocea nodosa and Posidonia oceanica on the NE Spanish coast. The population structure of both species changed much more with depth than leaf morphology and physiology. Leaf biomass declined 5- to 7-fold along the depth gradient reducing self-shading within the canopy, whereas the leaf area per unit leaf biomass and the photosynthesis-light response varied less than 1.5-fold among depths. Moreover, C. nodosa developed a greater proportion of leaves relative to rhizomes and roots at greater depths, thereby promoting the balance between photosynthesis and respiration in the shoots. C. nodosa, being a potentially fast-growing species compared to P. oceanica, had higher maximum photosynthetic and respiration rates as well as light compensation points for photosynthesis. Photosynthetic efficiency at low light, however, was almost the same for the 2 species as suggested by the relatively small differences in mass-specific light absorption. Only C. nodosa acclimated physiologically to depth as light-use efficiency increased, and light compensation point declined significantly from shallow to deep water. P. oceanica, however, possessed low respiration rates and slightly lower light compensation points values than C. nodosa throughout the depth range. Shoot mortality and recruitment rates were unaffected by rooting depth. C. nodosa stand experienced fast shoot turnover compared to P. oceanica, and shoot longevity of the former species decreased significantly with depth, suggesting higher risk of patch mortality at the depth limit. In contrast, P. oceanica shoot longevity was highest at great depths. Overall, these species differences in leaf metabolism and shoot dynamics suggest that C. nodosa responds faster to changing light conditions, whereas P. oceanica is able to survive longer at low irradiance due to low growth and respiratory maintenance rates. KEY WORDS: Seagrasses · Biomass partitioning · Shoot demography · Leaf production · Photosynthetic light response Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 236. Online publication date: July 03, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.

High summer temperatures amplify functional differences between coral‐ and algae‐dominated reef communities

Shifts from coral to algal dominance are expected to increase in tropical coral reefs as a result of anthropogenic disturbances. The consequences for key ecosystem functions such as primary productivity, calcification, and nutrient recycling are poorly understood, particularly under changing environmental conditions. We used a novel in situ incubation approach to compare functions of coral- and algae-dominated communities in the central Red Sea bimonthly over an entire year. In situ gross and net community primary productivity, calcification, dissolved organic carbon fluxes, dissolved inorganic nitrogen fluxes, and their respective activation energies were quantified to describe the effects of seasonal changes. Overall, coral-dominated communities exhibited 30% lower net productivity and 10 times higher calcification than algae-dominated communities. Estimated activation energies indicated a higher thermal sensitivity of coral-dominated communities. In these communities, net productivity and calcification were negatively correlated with temperature (>40% and >65% reduction, respectively, with +5°C increase from winter to summer), whereas carbon losses via respiration and dissolved organic carbon release more than doubled at higher temperatures. In contrast, algae-dominated communities doubled net productivity in summer, while calcification and dissolved organic carbon fluxes were unaffected. These results suggest pronounced changes in community functioning associated with coral-algal phase shifts. Algae-dominated communities may outcompete coral-dominated communities because of their higher productivity and carbon retention to support fast biomass accumulation while compromising the formation of important reef framework structures. Higher temperatures likely amplify these functional differences, indicating a high vulnerability of ecosystem functions of coral-dominated communities to temperatures even below coral bleaching thresholds. Our results suggest that ocean warming may not only cause but also amplify coral-algal phase shifts in coral reefs.

Reef accumulation is decoupled from recent degradation in the central and southern Red Sea

Bacterial activity in NW Mediterranean seagrass (Posidonia oceanica) sediments

Krill excretion and its effect on primary production

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 459:29-38 (2012) - DOI: https://doi.org/10.3354/meps09746 Krill excretion and its effect on primary production Pascal Lehette1,*, Antonio Tovar-Sánchez2, Carlos M. Duarte2,3, Santiago Hernández-León1 1Institute of Oceanography and Global Change, Universidad de Las Palmas de Gran Canaria, Spain 2Department of Global Change Research, IMEDEA, CSIC-UIB, Instituto Mediterráneo de Estudios Avanzados, Esporles, Mallorca, Spain 3The UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia *Email: pascal.lehette101@doctorandos.ulpgc.es ABSTRACT: During the austral summer, zooplankton excretion along the western Antarctic Peninsula was studied in a contrasting hydrographic regime including coastal and oceanic waters. In coastal waters, ammonium supply by mesozooplankton indicated a low contribution to fuel primary production. In oceanic waters, however, Antarctic krill Euphausia superba contributed a significant percentage to the nitrogen requirements of primary producers. Thus, the ontogenetic migration of adult krill during austral summer should be a key factor regulating the regenerated ammonium for primary production. A significant coupling of ammonium concentration in the water column and in situ krill biomass supported the significant role of krill excretion in the epipelagic realm. Results from short-term experiments with E. superba indicated that ammonium excretion rates were much higher than previously found. Because the use of experimental metabolic rates that are close to field rates would be more appropriate, we suggest to re-assess the ammonium supplied by the epipelagic marine biota. Moreover, the outcomes of experimental krill excretion rates, in situ measurements of ammonium and a review of data on primary production suggest that Antarctic krill sustain a high proportion of the daily phytoplankton production. KEY WORDS: Krill · Ammonium · Primary production · Euphausia superba · Southern Ocean · Austral summer · Western Antarctic Peninsula Full text in pdf format PreviousNextCite this article as: Lehette P, Tovar-Sánchez A, Duarte CM, Hernández-León S (2012) Krill excretion and its effect on primary production. Mar Ecol Prog Ser 459:29-38. https://doi.org/10.3354/meps09746 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 459. Online publication date: July 12, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

MalaMix dataset: contextual and metabarcoding data

1. INTRODUCTION <em>MalaMix </em>is a compiled metabarcoding dataset composed of 451 marine samples collected from a range of depths - from the surface (3m) to deep waters (as far down as 4800m). This dataset covers three ocean layers: the epi- (0-200m – including DCM), meso- (200-1000m) and bathypelagic (1000-4000m). <em>MalaMix</em> combines samples obtained during two oceanographic expeditions with similar sampling strategies: i) the Malaspina-2010 global expedition that produced 263 samples collected between December 2010 and July 2011 from 120 stations distributed along the tropical and subtropical portions (latitudes between 35° N and 40° S) of the Pacific, Atlantic and Indian oceans; and ii) the <em>HotMix</em> trans-Mediterranean cruise that produced 188 samples collected between April and May 2014 in 29 stations distributed along the whole Mediterranean Sea (from -5° W to 33° E) and the adjacent Northeast Atlantic Ocean. <em>MalaMix</em> comprises: a 16S-V4V5 rRNA gene ASV table (MalaMix_16S.csv); an 18S-V4 rRNA gene ASV table (MalaMix_18S.csv); two tables of contextual metadata (MalaMix_EnvData_16S and MalaMix_EnvData_18S) including 6 standardized environmental parameters (temperature [°C], salinity, fluorescence, PO₄³⁻[µmol L^-1], NO₃⁻[µmol L^-1], and SiO₂[µmol L^-1]) as well as species taxonomic and phylogenetic diversity metrics a table (MalaMix_FCdata.csv) with flow cytometry microbial counts [cell mL^-1] and bacterial activity measurements [pmol Leu L^-1 h^-1]; a README file (README_Metadata.csv) describing the meaning and units of each variable column in the metadata tables. The raw DNA sequences are publicly available at the European Nucleotide Archive (https://www.ebi.ac.uk/ena) under accession numbers PRJEB23913 [18S rRNA genes] &amp; PRJEB25224 [16S rRNA genes] for the Malaspina surface dataset; PRJEB23771 [18S rRNA genes] &amp; PRJEB45015 [16S rRNA genes] for the Malaspina vertical profiles; PRJEB45011 [16S rRNA genes] &amp; PRJEB45014 [18S rRNA genes] for the Malaspina deep sea dataset; and PRJEB44683 [18S rRNA genes] &amp; PRJEB44474 [16S rRNA genes] for the HotMix expedition. Further methodological details are available here: https://www.biorxiv.org/content/10.1101/2023.01.13.523743v1 2. FUTURE FORMAT CHANGES No major changes are expected for the main general format of the database. 3. ACKNOWLEDGMENTS The current dataset was generated with funds from the projects INTERACTOMICS (CTM2015-69936-P, MINECO, Spain), MicroEcoSystems (240904, RCN, Norway), MINIME (PID2019-105775RB-I00, AEI, Spain), and PID2021-125469NB-C31 (AEI, Spain), as well as DOREMI (CTM2012-34294) and HOTMIX (CTM2011-30010-C02-01 and CTM2011-30010-C02-02) of the Spanish Ministry of Economy and Innovation, co-financed with FEDER funds. 4. COPYRIGHT NOTICE<br> <br> This database is provided “as is” and without any warranty of any kind, of openly available for non-commerical purposes (CC BY-NC). <strong>CC BY-NC</strong> means that users can make use of the work (including copying, distributing, adapting and building upon the work), but only for noncommercial purposes and as long as attribution is given to the creator: https://oabooks-toolkit.org/lifecycle/article/4012101-choosing-a-license

Climate warming and Mediterranean seagrass

Flexible and Biofouling Independent Salinity Sensor

Abstract Salinity is one of the most relevant parameters in oceanography used to study properties of the oceans as well as the effects of climate change. Salinity measurements are challenging, due to the harsh environment that leads to corrosion and biofouling. In the context of animal monitors, salinity sensors should also be minimally intrusive and have a long lifetime. Here, a conductivity cell for salinity sensing is presented based on a single‐step laser irradiation process on flexible polyimide substrate. The sensors are characterized by lightweight, flexibility, low power consumption and low fabrication costs. A two‐electrode cell is used to measure the impedance, and thereby the conductivity, of the water in the MHz frequency range. It offers an accuracy of ±0.5 psu, which is not affected by sensor deformation. Deployment of the sensors in the Red Sea revealed that the materials are corrosion resistant and can withstand the harsh environment. While biofouling is strongly affecting commonly employed low frequency conductivity measurements, in the MHz frequency range, it acts like a short‐circuited capacitance. Hence, biofouling independent salinity sensing can be achieved using a two‐electrode impedance measurement at a frequency of 1 MHz.

Additional file 1 of Water mass age structures the auxiliary metabolic gene content of free-living and particle-attached deep ocean viral communities

Additional file 1: Table S1. Metadata of the collected samples and metagenomes. Table S2. Sequence data of the obtained viral genomes and genome fragments. Table S3. Functional and taxonomic annotation of the CDS encoded in the viral genomes and genome fragments. Table S4. Relative abundances of viral viral genomes and genome fragments across 58 metagenomes calculated as RPKM. Table S5. Relative abundances of viral KEGG KOs across 58 metagenomes calculated based on RPKM of individual viral viral genomes and genome fragments. Table S6. Relative abundances of viral KEGG pathways across 58 metagenomes calculated based on RPKM of individualviral genomes and genome fragments. Table S7. Relative abundances of viral KEGG metabolism across 58 metagenomes calculated based on RPKM of individual viral genomes and genome fragments. Table S8. Relative abundances of viruses grouped according to family level taxonomic affiliation based on RPKM of individual viral genomes and genome fragments. Table S9. Relative abundances of viruses grouped according to predicted host phylum (or class for Proteobacteria) taxonomic affiliation based on RPKM of individual viral scaffolds. Table S10. Results of Mann-Whitney tests used to compare the relative abundances of: viruses grouped according to predicted host phylum (or class for Proteobacteria), family level taxonomic affiliation, viral KEGG pathways, and viral KEGG metabolisms. Table S11. Results of Pearson and Spearman correlation analyses used to quantify the degrees of association between environmental parameters and the relative abundances of: viruses grouped according to predicted host phylum (or class for Proteobacteria), family level taxonomic affiliation, viral KEGG pathways, and viral KEGG metabolisms.

Thermal tolerance of Halophila stipulacea in its native and exotic distributional range [Dataset]

Growth and abundance of Synechococcus sp. in a Mediterranean Bay:seasonality and relationship with temperature

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 170:45-53 (1998) - doi:10.3354/meps170045 Growth and abundance of Synechococcus sp. in a Mediterranean Bay: seasonality and relationship with temperature Nona S. R. Agawin*, Carlos M. Duarte, Susana Agustí Centro de Estudios Avanzados de Blanes, CSIC, Camino de Santa Bàrbara s/n, E-17300 Blanes (Girona), Spain *E-mail: agawin@ceab.csic.es ABSTRACT: In this study, we confirm the relationship between temperature and Synechococcus sp. experimental growth rates (r = 0.87, p < 0.005) and provide evidence of the existence of a general relationship. This link leads to a strong seasonality of abundance and biomass of Synechococcus sp. in the Bay of Blanes (NW Mediterranean), which was followed for 2 yr (1995, 1996), with high values in summer months (6 x 107 cells l-1) and low values in winter (5 x 105 cells l-1). The growth rate achieved in summer months (1.5 d-1) is close to or at the maximum possible at the in situ water temperature. As a result, Synechococcus growth may exceed the grazing capacity of its predators in summer, and this explains its significant contribution of >30% of the total gross autotrophic production and >20% of the total autotrophic biomass in summer. Thus, Synechococcus is an important source of organic C and nutrients for the coastal Mediterranean food web in the summer. KEY WORDS: Synechococcus sp. · NW Mediterranean Sea · Growth and abundance · Temperature Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 170. Publication date: September 03, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research.

Érosion de la biodiversité marine : quelles solutions ?

The microcosm of particles within seagrass Posidonia oceanica canopies

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 181:289-295 (1999) - doi:10.3354/meps181289 The microcosm of particles within seagrass Posidonia oceanica canopies Carlos M. Duarte*, Esther Benavent, Maria del Carmen Sánchez Instituto Mediterráneo De Estudros Avanzados (IMEDEA), CSIC-UIB, c/ Miquel Marqués 21, E-07190 Esporles, Mallorca (Islas Baleares), Spain *Address for correspondence: Centro de Estudios Avanzados de Blanes, CSIC, Cami de Santa Barbara s/n, E-17300 Blanes, Spain. E-mail: duarte@ceab.csic.es ABSTRACT: Comparison of the amount and nature of suspended material within Posidonia oceanica canopies, in 6 meadows in the Spanish Mediterranean coast differing in extent and depth, with those in the overlying waters showed the canopies to be significantly enriched in particulate organic carbon, nitrogen and phosphorus relative to the overlying waters (on average, 87, 34 and 54% more C, N and P, respectively). Biovolume of detritus (both angiosperm-derived and plankton-derived) was large, particularly within seagrass canopies, where it dominated the seston pool (about 5-fold greater biovolume than that of living particles), compared to a roughly equal biovolume of detrital and living particles in the particle pools in the overlying waters. The dominance of detrital particles was further reflected in the high C/N and C/P ratios of the suspended materials (median atomic C:N:P ratios = 492:40.9:1 and 596:45:1 of the materials suspended within the canopy and in the overlying waters, respectively), which were intermediate between those of living plankton and P. oceanica. The relative enrichment of P. oceanica canopies by particles tended to be greatest when particle loads in the overlying waters were small, suggesting that the effect of seagrasses as traps of particles is enhanced in particle-poor waters. The results obtained support the hypothesis that the water within seagrass canopies is enriched by (mostly detrital) particles, particularly in particle-poor waters. This suggests that seagrasses not only contribute a substantial fraction of the particles themselves, but also act as sinks of particles. KEY WORDS: Seagrass · Seston · Sedimentation · Detritus Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 181. Publication date: May 18, 1999 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1999 Inter-Research.

Losses of Soil Organic Carbon with Deforestation in Mangroves of Madagascar

Pathways for Understanding Blue Carbon Microbiomes with Amplicon Sequencing

The capacity of Blue Carbon Ecosystems to act as carbon sinks is strongly influenced by the metabolism of soil-associated microbes, which ultimately determine how much carbon is accumulated or returned to the atmosphere. The rapid evolution of sequencing technologies has facilitated the generation of tremendous amounts of data on what taxa comprise belowground microbial assemblages, largely available as isolated datasets, offering an opportunity for synthesis research that informs progress on understanding Blue Carbon microbiomes. We identified questions that can be addressed with a synthesis approach, including the high variability across datasets, space, and time due to differing sampling techniques, ecosystem or vegetation specificity, and the relationship between microbiome community and edaphic properties, particularly soil carbon. To address these questions, we collated 34 16S rRNA amplicon sequencing datasets, including bulk soil or rhizosphere from seagrass, mangroves, and saltmarshes within publicly available repositories. We identified technical and theoretical challenges that precluded a synthesis of multiple studies with currently available data, and opportunities for addressing the knowledge gaps within Blue Carbon microbial ecology going forward. Here, we provide a standardisation toolbox that supports enacting tasks for the acquisition, management, and integration of Blue Carbon-associated sequencing data and metadata to potentially elucidate novel mechanisms behind Blue Carbon dynamics.

Beyond CO2: air-sea volatile organic carbon exchange in the Southern Ocean

Universal spatial properties of coral reefs

Georeferenced database on the spatial properties of all individual shallow-water tropical coral reefs worldwide. The dataset was obtained by processing and analyzing the global-scale coral reef benthic data provided by the Allen Coral Atlas (ACA), a publicly available dataset of high-resolution satellite imagery and machine learning-based coral reef classifications. The original data, already divided into different coral provinces, was segmented to identify the individual reefs of each province using a label assignment algorithm. This allows to analyze several spatial properties of coral reefs such as the size distribution, area-perimeter relationship, fractal dimensions and shape measures. The dataset contains measures of area, perimeter, fractal dimension, compactness and elongation index (diameter ratio) for each individual reef in each coral province.