Functional groups in marine phytoplankton assemblages dominated by diatoms in fjords of southern Chile

Alves‐de‐Souza, Catharina; González, María Teresa; Iriarte, José Luis

doi:10.1093/plankt/fbn079

Cited by 105 publications

(69 citation statements)

References 20 publications

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“…were associated with silicate-rich waters. Our data are consistent with other studies in the southern fjord system of Patagonia, where the phytoplankton community shows recurring changes in dominance and diversity of a number of diatom species (Iriarte et al, 2007;Alves-de-Souza et al, 2008;Iriarte and González, 2008;Montero et al, 2011), some of which have also been recorded in the sediments of the Puyuhuapi Channel .…”

Section: Discussionsupporting

confidence: 92%

“…The transition between these two periods appears to be rather abrupt, although the resolution of our in situ observations does not allow us to strongly substantiate this argument. However, similar shifts in other Patagonian fjords have been ascribed to fjordscale hydrographic changes driven by a seasonal changes in mesoscale wind forcing and solar radiation (Iriarte & González, 2008;Montero et al, 2011;Jacob et al, 2014).…”

Section: Discussionmentioning

confidence: 68%

“…Montero et al (2011) reported that the onset of the productive season in the Reloncaví Fjord (41°S, 72°W) coincided with a late winter relaxation of prevailing poleward winds. This seasonal shift in predominant winds and improved light conditions has been shown to influence the productivity of fjord and channel ecosystems (Iriarte & González, 2008;Montero et al, 2011). More locally, hydrodynamic patterns within a given fjord are strongly modulated by freshwater discharges, which can either intensify or weaken an estuarine type of circulation, and may modulate the occurrence and spatial extent of phytoplankton blooms (Goebel et al, 2005;González et al, 2013;Iriarte et al, 2014;Jacob et al, 2014).…”

Section: __________________mentioning

confidence: 99%

“…The productivity cycle within a number of Patagonian channels and fjords (41-51ºS) has been typically described in terms of two contrasting seasons: a productive season characterized by a marked spring diatom bloom followed by pulsed productivity events dominated by a sequence of different phytoplankton species, and then a non-productive season that predominantly features small phytoplankton cells (Iriarte et al, 2007;Iriarte & González, 2008;Czypionka et al, 2011;Montero et al, 2011;Paredes & Montecinos, 2011). Despite considerable recent research, uncertainty remains regarding the factors that modulate the seasonal phase change within Chilean fjords system, from non-productive in late autumn-winter to highly productive in late winter-autumn.…”

Section: __________________mentioning

confidence: 99%

“…Certain species are able to completely dominate a phytoplankton community (Legrand et al, 2003). In Chilean fjords ecosystems, diatoms are known to represent a significant component of the overall phytoplankton biomass (Iriarte et al, 2001;Cassis et al, 2002;Alves-de-Souza et al, 2008;Iriarte & González, 2008). In addition to efficiently transferring energy to higher trophic levels, diatoms make a significant contribution to the downward transfer of organic carbon (Iriarte et al, 2007;González et al, 2010;Montero et al, 2011;Iriarte et al 2013).…”

Section: __________________mentioning

confidence: 99%

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Diatom blooms and primary production in a channel ecosystem of central Patagonia

Montero

Daneri

Tapia

et al. 2017

lajar

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ABSTRACT.Here we report on the seasonal productivity cycle at a fixed station in the Puyuhuapi Channel (44ºS, 73ºW), Chilean Patagonia. The analysis of in situ water column data and longer-term records of satellitederived surface ocean color (Chl-a) highlighted two contrasting seasons. A more productive period occurred between August and April, where depth-integrated gross primary production (GPP) estimates ranged from 0.1 to 2.9 g C m -2 d -1, and a shorter, less-productive season lasted from May to July with GPP ranging from 0.03 to. Diatoms of the genera Pseudo-nitzschia, Skeletonema and Chaetoceros dominated the phytoplankton, and showed a pronounced seasonality greatly influenced by prevailing environmental conditions. Warmer waters were associated with high concentrations of Pseudo-nitzschia spp., while high abundances of Skeletonema spp. and Chaetoceros spp. were associated with fresher silicate-rich waters. A marked Skeletonema spp. bloom characterized the onset of the productive season in August 2008, and with some exceptions, the highest levels of GPP (1.5 to 2.9 g C m -2 d -1) were measured when Skeletonema dominated the phytoplankton community. Reduced production (low GPP) was observed during periods of increased discharge from the Cisnes River, whereas the "spring" diatom bloom (or late winter bloom in Puyuhuapi Channel) observed during August 2008 coincided with a ~50% drop in the freshwater discharge. We therefore suggest that periods of intensive freshwater Input, that increase the silicic acid concentrations in the upper layers, provide ideal growing conditions for diatoms as the freshwater flow subsequently recedes. Principal component analysis (PCA) suggests that a decrease in salinity, increase in silicic acid concentration, and growth of Skeletonema spp. and Chaetoceros spp., are probably key factors in the annual cycle of GPP in Puyuhuapi Channel.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 68%

Section: __________________mentioning

confidence: 99%

Section: __________________mentioning

confidence: 99%

Section: __________________mentioning

confidence: 99%

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Diatom blooms and primary production in a channel ecosystem of central Patagonia

Montero

Daneri

Tapia

et al. 2017

lajar

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A trait‐based framework for stream algal communities

Lange

Townsend

Matthaei

2015

Ecology and Evolution

118

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The use of trait‐based approaches to detect effects of land use and climate change on terrestrial plant and aquatic phytoplankton communities is increasing, but such a framework is still needed for benthic stream algae. Here we present a conceptual framework of morphological, physiological, behavioural and life‐history traits relating to resource acquisition and resistance to disturbance. We tested this approach by assessing the relationships between multiple anthropogenic stressors and algal traits at 43 stream sites. Our “natural experiment” was conducted along gradients of agricultural land‐use intensity (0–95% of the catchment in high‐producing pasture) and hydrological alteration (0–92% streamflow reduction resulting from water abstraction for irrigation) as well as related physicochemical variables (total nitrogen concentration and deposited fine sediment). Strategic choice of study sites meant that agricultural intensity and hydrological alteration were uncorrelated. We studied the relationships of seven traits (with 23 trait categories) to our environmental predictor variables using general linear models and an information‐theoretic model‐selection approach. Life form, nitrogen fixation and spore formation were key traits that showed the strongest relationships with environmental stressors. Overall, FI (farming intensity) exerted stronger effects on algal communities than hydrological alteration. The large‐bodied, non‐attached, filamentous algae that dominated under high farming intensities have limited dispersal abilities but may cope with unfavourable conditions through the formation of spores. Antagonistic interactions between FI and flow reduction were observed for some trait variables, whereas no interactions occurred for nitrogen concentration and fine sediment. Our conceptual framework was well supported by tests of ten specific hypotheses predicting effects of resource supply and disturbance on algal traits. Our study also shows that investigating a fairly comprehensive set of traits can help shed light on the drivers of algal community composition in situations where multiple stressors are operating. Further, to understand non‐linear and non‐additive effects of such drivers, communities need to be studied along multiple gradients of natural variation or anthropogenic stressors.

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Spatial distribution of brominated very short‐lived substances in the eastern Pacific

et al. 2013

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[1] Seawater concentrations and distributions of brominated very short-lived substances (BrVSLS), including bromoform (CHBr 3 ), dibromomethane (CH 2 Br 2 ), bromodichloromethane (CHBrCl 2 ), chlorodibromomethane (CHClBr 2 ), were measured in the upper water column (5-750 m) in the eastern Pacific. Inorganic nutrient, pigment concentrations, and picoplankton cell counts were measured to determine biogeochemical factors that affect the production and distribution of these BrVSLS. Elevated concentrations of BrVSLS were observed in coastal and tropical seawater. Concentration maxima for CHBr 3 , CH 2 Br 2 , and CHClBr 2 were observed below the mixed layer, near the subsurface chlorophyll a maxima, which suggest BrVSLS production may be related to photosynthetic biomass production. Our results also suggest that heterotrophic bacteria may also contribute to CH 2 Br 2 and CHBrCl 2 production in the water column. The maximum CHBrCl 2 concentration was observed at a depth much deeper than the euphotic zone, which suggests sources other than photosynthetic biomass. Elevated CHBrCl 2 concentrations in deeper waters were coincident with elevated CHCl 3 concentrations, which may be an evidence for successive chlorine substitution of CHBr 3 in deeper and older water masses.

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Functional groups in marine phytoplankton assemblages dominated by diatoms in fjords of southern Chile

Cited by 105 publications

References 20 publications

Diatom blooms and primary production in a channel ecosystem of central Patagonia

Diatom blooms and primary production in a channel ecosystem of central Patagonia

A trait‐based framework for stream algal communities

Spatial distribution of brominated very short‐lived substances in the eastern Pacific

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