Land–ocean gradient in haline stratification and its effects on plankton dynamics and trophic carbon fluxes in Chilean Patagonian fjords (47–50°S)

González, Humberto E.; Castro, Leonardo R.; Daneri, Giovanni; Iriarte, J. L.; Silva, N.; Tapia, Fabián J.; Teca, Elisabeth; Vargas, Cristian A.

doi:10.1016/j.pocean.2013.06.003

Cited by 72 publications

(71 citation statements)

References 69 publications

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“…Saline stratification of the water column of Puyuhuapi Fjord resulted in a vertical segregation of dissolved inorganic nutrients and chlorophyll-a concentrations, consistent with previous observations for a variety of biogeochemical parameters in other Patagonian fjords (González et al, 2013;Silva and Vargas, 2014;Gutiérrez et al, 2015;Ríos et al, 2016).…”

Section: Community Composition Of Prokaryotes In Water Masses Of Puyusupporting

confidence: 89%

“…This ecosystem is greatly influenced by rivers and the Patagonian Ice Fields (Pickard, 1971) and supports high rates of biological productivity and vertical export fluxes of carbon (Pantoja et al, 2005;González et al, 2010González et al, , 2011González et al, , 2013Montero et al, 2011Montero et al, , 2017a. The Patagonian fjord ecosystem as a whole is considered to represent a net sink of CO 2 (Torres et al, 2011;González et al, 2013) and of enhanced sedimentary burial of organic carbon (Sepúlveda et al, 2011;Smith et al, 2015). Previous studies within this coastal ecosystem have highlighted the role of winds, low-pressure systems, and freshwater discharge in driving cycles of biological productivity and composition of the phytoplankton community at seasonal and shorter time scales (Montero et al, 2011(Montero et al, , 2017a.…”

Section: Introductionmentioning

confidence: 98%

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Linking Seasonal Reduction of Microbial Diversity to Increase in Winter Temperature of Waters of a Chilean Patagonia Fjord

et al. 2018

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Since microorganisms play a major role in the biogeochemistry of the ocean, understanding structure and dynamics of natural microbial communities is crucial in assessing the impact of environmental changes on marine ecosystems. In order to identify key environmental drivers of microbial community structure in Chilean Patagonian fjords, we analyzed composition of the prokaryotic community over an annual cycle at a single sampling site in Puyuhuapi Fjord. Distinctive communities represented mainly by Actinomycetales, Rhodobacteraceae, Cryomorphaceae, and Flavobacteriaceae were associated with Estuarine Fresh Waters, whereas Cenarchaeaceae and Oceanospirillales were representative of Modified Sub Antarctic Waters present in the fjord. Salinity and oxygen were first-order factors explaining segregation of microbial communities in these contrasting water masses. Positive correlations of members of Flavobacteriaceae, Alteromonadales, and Verrucomicrobiales with diatoms in subsurface waters and of Flavobacteriales (Cryomorphaceae and Flavobacteriaceae), Rhodobacteraceae, and Pelagibacteraceae with dinoflagellates in surface waters suggest that phytoplankton composition could define specific niches for microorganisms in Puyuhuapi fjord waters. A dramatic reduction of richness and individual abundances within Flavobacteriaceae, Rhodobacteraceae, and Cenarchaeaceae families was principally explained by seasonal increase of surface water temperature, with major reduction associated with changes in temperature during winter conditions. Taxa that are sensitive to increased temperature are key components of organic matter and element cycling, and we therefore suggest that potential decrease in diversity associated with rising of surface water temperature could impact current biogeochemical status of Patagonian fjord ecosystems.

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Section: Community Composition Of Prokaryotes In Water Masses Of Puyusupporting

confidence: 89%

Section: Introductionmentioning

confidence: 98%

Linking Seasonal Reduction of Microbial Diversity to Increase in Winter Temperature of Waters of a Chilean Patagonia Fjord

et al. 2018

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“…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). Freshwater inputs appear to stabilize the water column and increase the concentration of silicic acid in the upper layers, favouring the occurrence of diatom dominated phytoplankton blooms.…”

Section: __________________mentioning

confidence: 99%

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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“…In the Patagonian fjords limnetic and oceanic features overlap generating strong vertical and horizontal physicochemical gradients (e.g., Sievers and Silva, 2008;González et al, 2013). At present, the interaction between the resulting surface freshwater layer and nutrient-rich saline bottom water (mixing and/or stability of the water column) strongly controls primary production fluctuations and species composition (e.g., Saggiomo et al, 1994;Pizarro et al, 2000;Iriarte et al, 2007;Torres et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Holocene variations in productivity associated with changes in glacier activity and freshwater flux in the central basin of the Strait of Magellan

Aracena

Kilian

Lange

et al. 2015

Palaeogeography, Palaeoclimatology, Palaeoecology

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One of the most important factors controlling fjord primary production in southernmost Patagonia is the variability in the thermohaline structure of the water column. In the present-day environment, thermal stratification is mostly related to freshwater input and in particular, the seasonal melting of glaciers. Here we assess whether this relation between fjord productivity and freshwater input holds true for the Holocene, using a sediment record from the central basin of the Strait of Magellan (core MD07-3132, 53°44.17′S; 70°19.03′W, 301 m). Our approach relies on a proxy-based reconstruction of fjord sea surface temperature (alkenone SST), paleosalinity, freshwater input, and paleoproductivity. The results indicate that, during the early Holocene, the accumulation rate (AR) of marine organic carbon was low (b 20 kg m −2 kyr −1), most likely due to high freshwater contribution resulting in low salinity and low SSTs. After 8.5 kyr BP and during the mid and late Holocene all the productivity proxies increase. The AR's of marine organic carbon (~30 kg m −2 kyr ) reached the highest values during the last millennium. This increase was probably driven by the marine transgression where marine macronutrient-rich waters entered into the central basin, while lowered precipitation and decreased meltwater input contributed to increase the basin's SSTs and salinity. The late Holocene rise in productivity was interrupted by a low salinity phase between 3.2 and 2.2 kyr BP, during which productivity returned to early Holocene conditions in response to increased input of glacial clays, as suggested by high values of K/Si ratio (~1.2). Our results indicate that meltwater contribution from glaciers plays a crucial role in controlling fjord productivity on seasonal to millennial timescales.

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Land–ocean gradient in haline stratification and its effects on plankton dynamics and trophic carbon fluxes in Chilean Patagonian fjords (47–50°S)

Cited by 72 publications

References 69 publications

Linking Seasonal Reduction of Microbial Diversity to Increase in Winter Temperature of Waters of a Chilean Patagonia Fjord

Linking Seasonal Reduction of Microbial Diversity to Increase in Winter Temperature of Waters of a Chilean Patagonia Fjord

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

Holocene variations in productivity associated with changes in glacier activity and freshwater flux in the central basin of the Strait of Magellan

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