Changes in phytoplankton production and upwelling intensity off A Coruña (NW Spain) for the last 28 years

Bode, Antonio; Álvarez, Marta; Ruiz-Villarreal, M.; Varela, Marta M.

doi:10.1007/s10236-019-01278-y

Cited by 21 publications

(21 citation statements)

References 71 publications

(115 reference statements)

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“…alternative forms of calculating RUE pp , that is, calculated sensu Ptacnik et al (2008) in terms of chlorophyll a (mg m −3 ) per unit of nitrate (µmol L −1 ), and sensu Lehtinen et al (2017) in terms of primary production (mg C m −3 h −1 ) per unit of nitrate (µmol L −1 ). Primary production was obtained from Bode et al (2019). These models were fitted to data covering the whole period, though restricting the phytoplankton species to the 55 taxa that were consistently identified along all three decades (Supplementary Table 1).…”

Section: Statistical Analysesmentioning

confidence: 99%

Phytoplankton Diversity Effect on Ecosystem Functioning in a Coastal Upwelling System

2020

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Species composition plays a key role in ecosystem functioning. Theoretical, experimental and field studies show positive effects of biodiversity on ecosystem processes. However, this link can differ between taxonomic and functional diversity components and also across trophic levels. These relationships have been hardly studied in planktonic communities of coastal upwelling systems. Using a 28-year time series of phytoplankton and zooplankton assemblages, we examined the effects of phytoplankton diversity on resource use efficiency (RUE, ratio of biomass to limiting resource) at the two trophic levels in the Galician upwelling system (NW Iberian peninsula). By fitting generalized least square models, we show that phytoplankton diversity was the best predictor for RUE across planktonic trophic levels. This link varied depending on the biodiversity component considered: while the effect of phytoplankton richness on RUE was positive for phytoplankton RUE and negative for zooplankton RUE, phytoplankton evenness effect was negative for phytoplankton RUE and positive for zooplankton RUE. Overall, taxonomic diversity had higher explanatory power than functional diversity, and variability in phytoplankton and zooplankton RUE decreased with increasing phytoplankton taxonomic diversity. Phytoplankton used resources more efficiently in warmer waters and at greater upwelling intensity, although these effects were not as strong as those for biodiversity. These results suggest that phytoplankton species numbers in highly dynamic upwelling systems are important for maintaining the planktonic biomass production leading us to hypothesize the relevance of complementarity effects. However, we further postulate that a selection effect may operate also because assemblages with low evenness were dominated by diatoms with specific functional traits increasing their ability to exploit resources more efficiently.

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Section: Statistical Analysesmentioning

confidence: 99%

Phytoplankton Diversity Effect on Ecosystem Functioning in a Coastal Upwelling System

2020

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“…Temperature and salinity profiles were obtained with a SeaBird SBE-25 CTD. Details on the analytical methods, plankton species composition and biomass, and environmental conditions at this station can be found elsewhere [19][20][21].…”

Section: Sampling and Determination Of Environmental Variablesmentioning

confidence: 99%

“…composition and biomass, and environmental conditions at this station can be found elsewhere [19][20][21]. We collected mesoplankton (200-5000 µm) by double oblique tows of a Juday-Bogorov net (200 µm mesh size) between the surface and the bottom.…”

Section: Sampling and Determination Of Environmental Variablesmentioning

confidence: 99%

“…High primary production, plankton biomass, as well as high yields of fisheries and aquaculture products are sustained mainly by the upwelling [17], but other nutrient inputs from continental origin were identified as being locally important [4,18]. In this region, decadal changes in primary production [16,19] and in zooplankton biomass and composition [19] were only related in part to upwelling intensity, as continental inputs of nutrients from rainfall and river outflow affected plankton populations at multiple scales.…”

Section: Introductionmentioning

confidence: 97%

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Effects of Upwelling Intensity on Nitrogen and Carbon Fluxes through the Planktonic Food Web off A Coruña (Galicia, NW Spain) Assessed with Stable Isotopes

2020

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The input of new nutrients by upwelling in shelf waters, and the associated carbon and nitrogen fluxes, can be traced by their stable isotope signatures in organic matter. Here, we analyze the relationships between upwelling intensity and natural abundance of stable carbon and nitrogen isotopes in seston, sedimented particles, and four plankton size fractions (200 to 5000 µm) sampled monthly during 2010 and 2011 in a seasonal upwelling ecosystem. Upwelling modified the seasonal warming stratification by introducing cold and nutrient-rich waters in subsurface layers, enhancing chlorophyll-a and diatom abundance. Seston and sedimented particles were enriched in heavy nitrogen (but not carbon) isotopes linearly with upwelling intensity, indicating a primary effect of upwelling on phytoplankton production. In contrast, all plankton fractions were enriched in heavy carbon isotopes with upwelling, mainly due to the consumption of diatoms. These results confirm the differential effect of upwelling on nitrogen and carbon fluxes in the plankton food web. Direct effects of the new nitrogen inputs on phytoplankton are less evident with the increase of plankton size as nitrogen is repeatedly recycled, while the enriched carbon of plankton suggests the consumption of diatoms during upwelling. We provide linear equations to assess the influence of changes in upwelling intensity on nitrogen and carbon fluxes in seston and plankton in this ecosystem, as well as to estimate reference baseline values for food web studies.

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“…The seasonal pattern of water column stratification, typical of temperate regions, is masked in the Atlantic Ocean off the western Galician coast by frequent upwelling pulses (the so-called NW Iberian upwelling system) between March and September-October (Casas et al, 1997), interrupted by periods of relaxation of winds or downwelling (Bode et al, 2019). As a result, there is an accumulation of autotrophically synthetized organic compounds which support the export offshore and sinking fluxes of organic matter (Bode et al, 1998;Álvarez-Salgado et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Vertical Niche Partitioning of Archaea and Bacteria Linked to Shifts in Dissolved Organic Matter Quality and Hydrography in North Atlantic Waters

Rodríguez‐Ramos

Nieto‐Cid

Auladell³

et al. 2021

Front. Mar. Sci.

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Understanding the factors that modulate prokaryotic assemblages and their niche partitioning in marine environments is a longstanding challenge in marine microbial ecology. This study analyzes amplicon sequence variant (ASV) diversity and co-occurrence of prokaryotic (Archaea and Bacteria) communities through coastal-oceanic gradients in the NW Iberian upwelling system and adjacent open-ocean (Atlantic Ocean). Biogeographic patterns were investigated in relation with environmental conditions, mainly focusing on the optical signature of the dissolved organic matter (DOM). Alpha- and beta-diversity were horizontally homogeneous [with the only exception of Archaea (∼1700 m depth), attributed to the influence of Mediterranean water, MW], while beta-diversity was significantly vertically stratified. Prokaryotic communities were structured in four clusters (upper subsurface, lower subsurface, intermediate, and deep clusters). Deep (>2000 m) archaeal and bacterial assemblages, and intermediate (500-2000 m) Bacteria (mainly SAR202 and SAR406), were significantly related to humic-like DOM (FDOM-M), while intermediate Archaea were additionally related to biogeochemical attributes of the high-salinity signature of MW. Lower subsurface (100-500 m) Archaea (particularly one ASV belonging to the genus Candidatus Nitrosopelagicus) were mainly related to the imprint of high-salinity MW, while upper subsurface (≤100 m) archaeal assemblages (particularly some ASVs belonging to Marine Group II) were linked to protein-like DOM (aCDOM254). Conversely, both upper and lower subsurface bacterial assemblages were mainly linked to aCDOM254 (particularly ASVs belonging to Rhodobacteraceae, Cyanobacteria, and Flavobacteriaceae) and nitrite concentration (mainly members of Planctomycetes). Most importantly, our analysis unveiled depth-ecotypes, such as the ASVs MarG.II_1 belonging to the archaeal deep cluster (linked to FDOM-M) and MarG.II_2 belonging to the upper subsurface cluster (related to FDOM-T and aCDOM254). This result strongly suggests DOM-mediated vertical niche differentiation, with further implications for ecosystem functioning. Similarly, positive and negative co-occurrence relationships also suggested niche partitioning (e.g., between the closely related ASVs Thaum._Nit._Nit._Nit._1 and _2) and competitive exclusion (e.g., between Thaum._Nit._Nit._Nit._4 and _5), supporting the finding of non-randomly, vertically structured prokaryotic communities. Overall, differences between Archaea and Bacteria and among closely related ASVs were revealed in their preferential relationship with compositional changes in the DOM pool and environmental forcing. Our results provide new insights on the ecological processes shaping prokaryotic assembly and biogeography.

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Changes in phytoplankton production and upwelling intensity off A Coruña (NW Spain) for the last 28 years

Cited by 21 publications

References 71 publications

Phytoplankton Diversity Effect on Ecosystem Functioning in a Coastal Upwelling System

Phytoplankton Diversity Effect on Ecosystem Functioning in a Coastal Upwelling System

Effects of Upwelling Intensity on Nitrogen and Carbon Fluxes through the Planktonic Food Web off A Coruña (Galicia, NW Spain) Assessed with Stable Isotopes

Vertical Niche Partitioning of Archaea and Bacteria Linked to Shifts in Dissolved Organic Matter Quality and Hydrography in North Atlantic Waters

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