1,721,051 research outputs found
Phytoplankton biomass and production during late austral spring (1991) and summer (1993) in the Bransfield Strait
No full textPhytoplankton biomass and productivity were measured during two cruises in the Bransfield Strait in December 1991 (D91) and January/February 1993 (J93). Strong seasonal variability in productivity values was observed due to differences in the physiological response of phytoplankton. However, although the photosynthetic capacity of phytoplankton was markedly lower in D91 [P m B=0.61 ± 0.25 mg C (mg Chla)−1 h−1] than in J93 [P m B=2.18 ± 0.91 mg C (mg Chla)−1 h−1], average water column chlorophyll values in different areas of the strait were approximately similar in D91 (49–78 mg Chla m−2) and J93 (22–76 mg Chla m−2). The spatial distribution of chlorophyll was patchy and generally associated with the influence of the different water masses that meet together in the Bransfield Strait. No correlation was found between the mixed layer depth and either the integrated chlorophyll or the productivity. Our results suggest that major phytoplankton blooms in the Bransfield Strait are advected from the nearby Gerlache Strait or Bellingshausen Sea following the main eastward surface currents.22110,966Q3SCI
Phytoplankton metabolism in a stratified nearshore ecosystem with recurrent Harmful Algal Blooms (HABs)
No full textDatasets from HAB monitoring program in Mallorc
Phytoplankton metabolism in a stratified nearshore ecosystem with recurrent Harmful Algal Blooms (HABs)
No full text<p>Datasets from HAB monitoring program in Mallorca</p>
Pushing and pulling an algal bloom: Physical controls of diel variability in nearshore phytoplankton biomass
No full textHigh-biomass microalgal blooms frequently occur in littoral environments worldwide, often causing noxious effects on aquatic ecosystems and coastal communities. Here, we combine field observations and a simple retention–dispersion model to disentangle the short-term (∼hours) environmental drivers shaping the nearshore dynamics of such outbreaks. Temperature, salinity, fluorescence, current velocities, and meteorological variables were measured in the nearshore waters of a coastal location in Mallorca (Balearic Islands) during the summer of 2018. Daily averages from field data were used to adjust wind and buoyancy flow variations into a one-dimensional advection–diffusion model in the cross-shore direction. Results reveal that the interplay between wind forcing and cross-shore density gradients drives an alternating retention–dispersion mechanism, effectively explaining the observed diel chlorophyll variability within the nearshore boundary. This simplified model captures the primary dynamics of the bloom, isolating key factors that influence its behavior and offering practical insights for coastal water quality monitoring and management.This research was supported by funding from the European Union’s H2020 programme under the Marie Skłodowska-Curie grant agreement No. 955910, as well as projects DIACOM (PID2022-143018NB-I00) and HABSYS (TED2021-132886B-I00 PRTR) funded by the Ministerio de Ciencia, Innovación y Universidades (MICINN), the Agencia Estatal de Investigación (AEI), and the Fondo Europeo de Desarrollo Regional (FEDER, UE) . The work was carried out within the framework of the activities of the Spanish Government through the “María de Maeztu Centre of Excellence” accreditation awarded to IMEDEA.Peer reviewe
Patterns of chlorophyll interannual variability in Mediterranean biogeographical regions
No full textThe Mediterranean Sea exhibits a strong basin and regional scale phytoplankton variability correlated to its semi-enclosed nature, complex orography and the variety of physical and chemical processes that regulate its productivity. Herein, using 17 years of ocean-color composites, we investigate differences in the regional patterns of interannual variability in satellite-derived chlorophyll (Chl), a proxy for phytoplankton biomass. A neural network classification, based on the Self-Organizing Maps (SOM) analysis in the time domain, is used to reveal regions of similar temporal variability of Chl in the Mediterranean Sea. Characteristic temporal patterns extracted by the SOM analysis show different scales of variation that can be related to already identified oceanographic features and biogeochemical variability in the Mediterranean Sea. Clear differences are noticed between regions located in the Western basin and Adriatic Sea, where rivers, winter mixing and winds are known to drive variations in primary production at regional scale and regions located in the Eastern basin, represented by a large and rather homogeneous region. Using the SOM-defined characteristic temporal patterns of Chl, we analyzed the regional influence of the North Atlantic Oscillation (NAO) and El Niño Southern Oscillation (ENSO) in the long-term (>1 year) Chl variability. Our results indicate that NAO has more influence in the Chl variations occurring in regions located in the Western basin whereas ENSO exhibits higher impact on the central Mediterranean and Eastern basin during its positive phase. Both NAO and ENSO show non-stationary coherence with Mediterranean Chl. The analysis also reveals a sharp regime shift occurring in 2004–2007, when NAO changed from positive to negative values. This shift particularly affected the winter phytoplankton biomass and it is indicative of climate driven ecosystem-level changes in the Mediterranean Sea. Our results stablish a regional connection between interannual phytoplankton variability exhibited in different regions of the Mediterranean Sea and climate variations.Peer reviewe
Phytoplankton metabolism in a stratified nearshore ecosystem with recurrent harmful algal blooms (HABs)
No full textThe coastal ocean is experiencing changes in its physical and chemical properties that strongly affect planktonic metabolism assemblages and, in some cases, favor the occurrence of harmful algal blooms (HABs). Here we analyze the variations in phytoplankton biomass, gross and net primary production (NCP) as well as community respiration (CR) at two nearshore sampling sites (P1 and P2) located at a Mediterranean beach where high biomass HABs are recurrent. At P1, the most exposed site, phytoplankton chlorophyll was generally low, whereas dinoflagellates outbreaks of the genus Gymnodinium and Alexandrium were recurrent during summer at P2 spanning for 10-20 days. During bloom episodes, NCP increased up to 10-fold (>80 mmol O2 m-3 day-1). Contrastingly, variation in CR only reached an average of 1.8-fold the rates of non-bloom conditions. Remarkably, although the enhanced NCP:CR ratio suggests net autotrophic population growth, production per unit biomass at P1 and P2 was not significantly different. Our results indicate that although summer conditions favor the necessary primary production enhancement leading to HAB occurrences, the short-term dynamics driving high biomass episodes are not driven by metabolic variations but instead are governed by subtle accumulative processes of some flagellate species in the nutrient-rich nearshore environment.This research was financed by HYDROALGAL (RTC-2016-4812-5) project and partially carried out within the framework of the activities of the Spanish Government through the “María de Maeztu Centre of Excellence” accreditation to IMEDEA (CSIC-UIB) (CEX2021-001198-M). A.R-de-G. was supported by a post-doctoral fellowship “Incorporacion de personal investigador” funded by the Ministry of Innovation, Research and Tourism of the Balearic Island Government.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001198-M).Peer reviewe
El papel de los eventos episódicos en el desarrollo de proliferaciones fitoplanctónica
No full textComunicación presentada en la XI Reunión Ibérica sobre Microalgas Nocivas y Biotoxinas, celebrada del 30 de mayo al 1 de junio de 2011 en Bilbao (España)Peer Reviewe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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