Southern Ocean Primary Productivity: Variability and a View to the Future

Smith, Walker O; Comiso, Josefino C.

doi:10.5479/si.097884601x.23

Cited by 5 publications

(3 citation statements)

References 42 publications

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“…Since Cl − concentrations in aerosols are typically correlated with SO 4 2− in remote sites, it is clear evidence of their major marine sources 12 . In the Antarctic Maritime environment, an 8-year aerosol continuous monitoring conducted at South Shetland Islands 13 demonstrated that atmospheric chlorine de cit is enhanced, especially in the ne mode particles and during the austral summer, when the regional primary productivity reaches a maximum 14 . Although the de cit Cl − is partially related to organic acids, such as oxalic acid, fulvic acid, and malonic acid 15 , due to the de ciency of organic emissions in the Antarctic environment, the Cl-depletion is predominantly associated with particle processing by inorganic acids 11 .…”

Section: Introductionmentioning

confidence: 99%

Ozone depletion in the Antarctic region triggers intense changes in sea salt geochemistry

Gonçalves

Evangelista

Weis³

et al. 2022

Preprint

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The Antarctic environment has been used as a natural field laboratory to investigate the impacts of enhanced UV-B radiation over the polar terrestrial biota, marine life, and the cryosphere. UV-B increased levels occur due to the stratospheric ozone depletion detected since the early 80s’ decade. The real dimension of the ozone depletion threat to the Antarctic environments and the atmospheric chemistry remains uncertain. This work presents new pieces of evidence of this impact on individual aerosol particles sampled in West Antarctica, using a synchrotron-based multi-element microscopic/molecular speciation method. We used the Scanning Transmission X-ray microscopy with Near-Edge X-ray Absorption Fine Structure Spectroscopy combined with Computer-Controlled Scanning Electron Microscopy to identify the molecular changes in sea salt particles due to photolytic processes involving chlorine-enriched particles during the ozone depletion period since the 80´s decade. Combining our data with ice core records, we deduce that the modern effects of UV-B on the tropospheric chlorine geochemistry have no precedent for the Holocene.

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Section: Introductionmentioning

confidence: 99%

Ozone depletion in the Antarctic region triggers intense changes in sea salt geochemistry

Gonçalves

Evangelista

Weis³

et al. 2022

Preprint

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“…The Ross Sea is one of the most productive regions of the Southern Ocean [ Comiso et al ., ; Smith and Comiso , ], accounting for 25–30% of the total annual primary production south of 50°S [ Arrigo et al ., ]. Triggered by increasing surface irradiance, shoaling surface layer, and abundant iron, the spring bloom is the most productive time of year in the Ross Sea [ Smith et al ., ; Peloquin and Smith , ; Smith et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Quantifying phytoplankton productivity and photoinhibition in the Ross Sea Polynya with large eddy simulation of Langmuir circulation

et al. 2017

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Southern Ocean phytoplankton assemblages acclimated to low‐light environments that result from deep mixing are often sensitive to ultraviolet and high photosynthetically available radiation. In such assemblages, exposures to inhibitory irradiance near the surface result in loss of photosynthetic capacity that is not rapidly recovered and can depress photosynthesis after transport below depths penetrated by inhibitory irradiance. We used a coupled biophysical modeling approach to quantify the reduction in primary productivity due to photoinhibition based upon experiments and observations made during the spring bloom in Ross Sea Polynya (RSP). Large eddy simulation (LES) was used to generate depth trajectories representative of observed Langmuir circulation that were passed through an underwater light field to yield time series of spectral irradiance representative of what phytoplankton would have experienced in situ. These were used to drive an assemblage‐specific photosynthesis‐irradiance model with inhibition determined from a biological weighting function and repair rate estimated from shipboard experiments on the local assemblage. We estimate the daily depth‐integrated productivity was 230 mmol C m−2. This estimate includes a 6–7% reduction in daily depth‐integrated productivity over potential productivity (i.e., effects of photoinhibition excluded). When trajectory depths were fixed (no vertical transport), the reduction in productivity was nearly double. Relative to LES estimates, there was slightly less depth‐integrated photoinhibition with random walk trajectories and nearly twice as much with circular rotations. This suggests it is important to account for turbulence when simulating the effects of vertical mixing on photoinhibition due to the kinetics of photodamage and repair.

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“…However, there is little quantitative information on the photosynthetic response to UV in the Ross Sea and on the responses of natural assemblages of the colonial prymnesiophyte Phaeocystis antarctica, despite the important contribution of the Ross Sea to overall productivity of the Southern Ocean (see Smith and Comiso, 2009, and references therein). P. antarctica is the dominant phytoplankter in the Ross Sea, particularly during the early-spring period of ozone depletion.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Phytoplankton and Bacterial Productivity by Solar Radiation in the Ross Sea Polynya

Neale¹,

Jeffrey²,

Sobrino³

et al. 2009

Smithsonian at the Poles : Contributions to International Polar Year Science

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Southern Ocean Primary Productivity: Variability and a View to the Future

Cited by 5 publications

References 42 publications

Ozone depletion in the Antarctic region triggers intense changes in sea salt geochemistry

Ozone depletion in the Antarctic region triggers intense changes in sea salt geochemistry

Quantifying phytoplankton productivity and photoinhibition in the Ross Sea Polynya with large eddy simulation of Langmuir circulation

Inhibition of Phytoplankton and Bacterial Productivity by Solar Radiation in the Ross Sea Polynya

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