Intrathermocline eddies at the Juan Fernandez Archipelago, southeastern Pacific Ocean

Andrade, Isabel; Hormazábal, Samuel; Combes, Vincent

doi:10.3856/vol42-issue4-fulltext-14

Cited by 10 publications

(12 citation statements)

References 50 publications

(79 reference statements)

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“…In that case, perhaps it is appropriate to consider that the present study documented a similar resistance of offshore eastern South Pacific A morphotype strains to that of coastal strains from high-CO 2 -low-pH waters. Although the offshore populations should be exposed less to high-CO 2 -lowpH conditions, they might experience such conditions occasionally: intra-thermocline eddies, subsurface lenses between approximately 100 and 500 m depth, have recently been documented to transport subsurface waters low in dissolved O 2 in an offshore direction in the eastern South Pacific (Andrade et al, 2014;Combes et al, 2015). These eddies would also be expected to be high in CO 2 and low in pH, and intrusions of such water might affect organisms at the base of the euphotic zone.…”

Section: P Von Dassow Et Al: Over-calcified Forms Of the Coccolithomentioning

confidence: 99%

Over-calcified forms of the coccolithophore Emiliania huxleyi in high-CO2 waters are not preadapted to ocean acidification

et al. 2018

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Abstract. Marine multicellular organisms inhabiting waters with natural high fluctuations in pH appear more tolerant to acidification than conspecifics occurring in nearby stable waters, suggesting that environments of fluctuating pH hold genetic reservoirs for adaptation of key groups to ocean acidification (OA). The abundant and cosmopolitan calcifying phytoplankton Emiliania huxleyi exhibits a range of morphotypes with varying degrees of coccolith mineralization. We show that E. huxleyi populations in the naturally acidified upwelling waters of the eastern South Pacific, where pH drops below 7.8 as is predicted for the global surface ocean by the year 2100, are dominated by exceptionally over-calcified morphotypes whose distal coccolith shield can be almost solid calcite. Shifts in morphotype composition of E. huxleyi populations correlate with changes in carbonate system parameters. We tested if these correlations indicate that the hyper-calcified morphotype is adapted to OA. In experimental exposures to present-day vs. future pCO2 (400 vs. 1200 µatm), the over-calcified morphotypes showed the same growth inhibition (−29.1±6.3 %) as moderately calcified morphotypes isolated from non-acidified water (−30.7±8.8 %). Under the high-CO2–low-pH condition, production rates of particulate organic carbon (POC) increased, while production rates of particulate inorganic carbon (PIC) were maintained or decreased slightly (but not significantly), leading to lowered PIC ∕ POC ratios in all strains. There were no consistent correlations of response intensity with strain origin. The high-CO2–low-pH condition affected coccolith morphology equally or more strongly in over-calcified strains compared to moderately calcified strains. High-CO2–low-pH conditions appear not to directly select for exceptionally over-calcified morphotypes over other morphotypes, but perhaps indirectly by ecologically correlated factors. More generally, these results suggest that oceanic planktonic microorganisms, despite their rapid turnover and large population sizes, do not necessarily exhibit adaptations to naturally high-CO2 upwellings, and this ubiquitous coccolithophore may be near the limit of its capacity to adapt to ongoing ocean acidification.

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Section: P Von Dassow Et Al: Over-calcified Forms Of the Coccolithomentioning

confidence: 99%

Over-calcified forms of the coccolithophore Emiliania huxleyi in high-CO2 waters are not preadapted to ocean acidification

et al. 2018

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“…The interaction between the physical forcings (e.g., wind and currents) and the seamount/island topography fosters the formation of meso and submesoescale eddies, which promotes the injection of macro and micronutrients into the euphotic zone stimulating biological productivity (Sangrà et al, 2007;Hasegawa et al, 2009;Andrade et al, 2014aAndrade et al, , 2014bAndrade et al, , 2014c. In the chain of seamounts and islands associated with the Easter Submarine Alignment and the Juan Fernández Ridge, significant increases in Chla have been observed, the variability of which is strongly influenced by the presence of meso and submesoscale eddies (Andrade et al, 2014a(Andrade et al, , 2014c. Surface and subsurface mesoscale eddies formed along the continental coast travel west at speeds on the order of 2 km d -1 (Hormazábal et al, 2013;Andrade et al, 2014a).…”

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confidence: 99%

“…In the chain of seamounts and islands associated with the Easter Submarine Alignment and the Juan Fernández Ridge, significant increases in Chla have been observed, the variability of which is strongly influenced by the presence of meso and submesoscale eddies (Andrade et al, 2014a(Andrade et al, , 2014c. Surface and subsurface mesoscale eddies formed along the continental coast travel west at speeds on the order of 2 km d -1 (Hormazábal et al, 2013;Andrade et al, 2014a). Depending on the disapation methods, some of these eddies may reach Easter Island after ~5 years while others may reach Robinson Crusoe Island after ~8 months (Andrade et al, 2014a(Andrade et al, , 2014b.…”

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confidence: 99%

“…Surface and subsurface mesoscale eddies formed along the continental coast travel west at speeds on the order of 2 km d -1 (Hormazábal et al, 2013;Andrade et al, 2014a). Depending on the disapation methods, some of these eddies may reach Easter Island after ~5 years while others may reach Robinson Crusoe Island after ~8 months (Andrade et al, 2014a(Andrade et al, , 2014b. The surface and subsurface anticyclonic eddies that interact with the Juan Fernández Archipelago are formed primarily within the coastal transition zone between 33° and 39°S (Andrade et al, 2014a).…”

mentioning

confidence: 99%

“…Depending on the disapation methods, some of these eddies may reach Easter Island after ~5 years while others may reach Robinson Crusoe Island after ~8 months (Andrade et al, 2014a(Andrade et al, , 2014b. The surface and subsurface anticyclonic eddies that interact with the Juan Fernández Archipelago are formed primarily within the coastal transition zone between 33° and 39°S (Andrade et al, 2014a). The transport associated with these eddies could have deep implications for the connectivity of biological communities between islands and between island and mainland areas.…”

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confidence: 99%

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Overview of recent advances in oceanographic, ecological and fisheries research on oceanic islands in the southeastern Pacific Ocean

Fernández

Hormazábal

2014

lajar

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Local and remote physical processes driving variability of the planktonic system in the Juan Fernández Archipelago: A multidisciplinary framework providing conservation insights

Parada

Ernst

Cornejo-Guzmán

et al. 2021

Aquatic Conservation

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1. The Juan Fernandez Ridge, a vulnerable marine ecosystem located far off the coast of central Chile and formed by several seamounts, guyots and three islands (Robinson Crusoe, Santa Clara and Alejandro Selkirk), has recently been declared a Coastal Marine Protected Area of Multiple Uses with several National Parks embedded in it. 2. Recent studies have highlighted the influence of remote and local oceanographic structures on the hydrographic dynamics of this ridge. However, there is still a gap in understanding how they affect the structure and dynamics of the surrounding insular planktonic communities. 3. A hydroacoustic and oceanographic survey was conducted during the austral spring (October 2016), including hydrographic and zooplankton sampling around Robinson Crusoe Island. Oceanographic features were identified and tracked using satellite data (chlorophyll-a (Chl-a) and sea surface temperature) and modelling results. 4. Two events of Chl-a increase relative to a threshold (>0.45 mg m −3) were forced by different physical processes, both affecting the western side of Robinson Crusoe Island. In event A during the cruise period, Chl-a subsurface maxima were associated with the arrival of a coastal meander originating on the continental shelf off Chile (remote process); the zooplankton was dominated by copepods and salps, with an evident coastal-oceanic gradient. In event B, Chl-a maxima were linked to a local upwelling forced by the intensification of a localized SSW wind. No influence of remote eddies or local Von Kármán vortices on Chl-a distribution was observed. 5. These findings highlight the influence of remote and local physical processes on the structure of planktonic communities around Robinson Crusoe Island. Understanding the variability of these mechanisms and their effects at the base of the pelagic food web is critical in adopting an ecosystem-level approach.

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Intrathermocline eddies at the Juan Fernandez Archipelago, southeastern Pacific Ocean

Cited by 10 publications

References 50 publications

Over-calcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high-CO<sub>2</sub> waters are not preadapted to ocean acidification

Over-calcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high-CO<sub>2</sub> waters are not preadapted to ocean acidification

Overview of recent advances in oceanographic, ecological and fisheries research on oceanic islands in the southeastern Pacific Ocean

Local and remote physical processes driving variability of the planktonic system in the Juan Fernández Archipelago: A multidisciplinary framework providing conservation insights

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Intrathermocline eddies at the Juan Fernandez Archipelago, southeastern Pacific Ocean

Cited by 10 publications

References 50 publications

Over-calcified forms of the coccolithophore &lt;i&gt;Emiliania huxleyi&lt;/i&gt; in high-CO&lt;sub&gt;2&lt;/sub&gt; waters are not preadapted to ocean acidification

Over-calcified forms of the coccolithophore &lt;i&gt;Emiliania huxleyi&lt;/i&gt; in high-CO&lt;sub&gt;2&lt;/sub&gt; waters are not preadapted to ocean acidification

Overview of recent advances in oceanographic, ecological and fisheries research on oceanic islands in the southeastern Pacific Ocean

Local and remote physical processes driving variability of the planktonic system in the Juan Fernández Archipelago: A multidisciplinary framework providing conservation insights

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Product

Resources

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Over-calcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high-CO<sub>2</sub> waters are not preadapted to ocean acidification

Over-calcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high-CO<sub>2</sub> waters are not preadapted to ocean acidification