On the hydrography of Puyuhuapi Channel, Chilean Patagonia

Schneider, Wolfgang; Peréz-Santos, Iván; Ross, Lauren; Bravo, Luis; Seguel, Romanet; Hernández, Freddy

doi:10.1016/j.pocean.2014.03.007

Cited by 66 publications

(71 citation statements)

References 14 publications

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“…The freshwater surface layer exits the Puyuhuapi Channel through the Jacaf Channel as water from the Cisnes River is pushed to the north and out towards the Moraleda channel. Overall, the hydrography of the whole Puyuhuapi channel is strongly influenced by the Cisnes River, which is the main source of freshwater discharge into this basin (Calvete & Sobarzo, 2011;Schneider et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…The deeper saline water originates from SubAntarctic Surface Water characteristic of open ocean environments in these latitudes (Chaigneau & Pizarro, 2005). The freshwater upper layer is supplied by the Cisnes River, several smaller rivers, and rain runoff, and it is a permanent feature of the Puyuhuapi Channel, although the degree of mixing with deeper saline water is seasonally variable (Schneider et al, 2014). Based on recent studies in other fjord ecosystems in the region, we hypothesized that the seasonal pattern of productivity in the Puyuhuapi area may be strongly influenced by freshwater input with a consequential series of blooms dominated by diatom species.…”

Section: __________________mentioning

confidence: 99%

“…1). The channel runs in a N-NE direction and connects directly to the open sea via the Moraleda Channel at its mouth, and through the Jacaf Channel near the head (Schneider et al, 2014;Fig. 1).…”

Section: Study Area and Sampling Strategymentioning

confidence: 99%

“…The Puyuhuapi Channel receives freshwater discharge from the Ventisqueros (north and south), Pascua and Cisnes rivers, plus additional inputs from numerous creeks and rainfall (Calvete & Sobarzo, 2011). The freshwater input drives an estuarine type of circulation, with a thin layer of freshwater flowing from the continent, on top of a thicker layer of oceanic Sub- Antarctic Waters (Silva et al, 2009;Schneider et al, 2014). Freshwater coming from the continent is loaded with silicic acid while Sub-Antarctic Waters (SAAW) is enriched with nitrate and orthophosphate (Silva, 2008).…”

Section: Study Area and Sampling Strategymentioning

confidence: 99%

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

Montero

Daneri

Tapia

et al. 2017

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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: Discussionmentioning

confidence: 99%

Section: __________________mentioning

confidence: 99%

Section: Study Area and Sampling Strategymentioning

confidence: 99%

Section: Study Area and Sampling Strategymentioning

confidence: 99%

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

Montero

Daneri

Tapia

et al. 2017

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“…This suggests that the origin of hypoxia was low ventilation, as it was proposed by Silva et al (1998) and Schneider et al (2014). Nevertheless, lowest DO values were recorded above the southern sill depth (150 m), which indicates that other processes, such as organic matter remineralization, could be contributing to DO reduction and hypoxia (Silva, 2006).…”

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confidence: 60%

Deep ventilation event during fall and winter 2015 in the Puyuhuapi Fjord (44.6 S)

Peréz-Santos

2017

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ABSTRACT. The Puyuhuapi Fjord has previously been reported as one of the hypoxic fjords in Patagonia (dissolved oxygen -DO below 2 mL L -1 ). Hydrographic sampling between 1995-2015 confirmed hypoxia below 100 m depth, down to the bottom (250 m). A line of sensors at an oceanographic mooring in Puyuhuapi were deployed to continuously record the temporal-vertical behaviour of water column temperature and salinity from the surface down to 120 m, from February to July 2015. A Multi-parameter water quality sonde was deployed at the bottom of the line, with a DO optical sensor. From February to mid-May, hypoxia was sustained (1.4-1.6 mL L -1 ). However, from May until the end of June, DO values increased (2.8 mL L -1 ), exceeding the hypoxia threshold. This was the first event of deep ventilation reported in a Patagonian fjord. During this time period, deep water temperatures increased by 1.3°C, coinciding with the decreased in salinity from 33.6 to 32.8. The main cause of this event was attributed to the arrival of a new volume of mixed oceanic water into the Fjord, transported by Modified Subantartic Water, with warm temperatures and slightly higher DO values, given its origin in the surface layer of the outer region of the Patagonian fjords and channels.

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Three‐dimensional tidal flow in a fjord‐like basin with converging width: An analytical model

et al. 2017

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A three‐dimensional analytical model was used to understand tidal dynamics in deep and narrow (fjord‐like) basins. This model allows the width of the basin to decay exponentially with along‐channel distance from the mouth. Both the length scale of exponential convergence Lb∗ and the friction parameter Av∗ (vertical eddy viscosity) were the free parameters. Model results show amplification of the tidal amplitude toward the head of the basin. Amplification depends on the narrowing rate of the funnel‐like width of the channel and on friction. Cross‐channel variations in along‐channel tidal flow are also sensitive to the friction parameter. A typical along‐channel tidal flow distribution was found across the channel when the vertical eddy viscosity was characteristic of a basin with strong friction, or the Stokes number was larger than 0.1 (St > 0.1). Maximum along‐channel tidal velocities (ranging from 0.25 to 0.5 m s−1 depending on width convergence strength) were located in the center of the basin and at the surface. Decreasing values of the Stokes number, St < 0.1, resulted in along‐channel velocity maxima located near the lateral boundaries and subsurface in the middle of the channel. These tidal flow distributions were explained by a critical value of St and were verified with observations from Reloncavi Fjord, Chilean Patagonia yielding good agreement.

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On the hydrography of Puyuhuapi Channel, Chilean Patagonia

Cited by 66 publications

References 14 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

Deep ventilation event during fall and winter 2015 in the Puyuhuapi Fjord (44.6 S)

Three‐dimensional tidal flow in a fjord‐like basin with converging width: An analytical model

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