The extent of the ozone hole over South America during the spring of 1993, 1994 and 1995

Serrano, A.; Cárcer, I. Aguirre de; Tocho, Jorge O.; Crino, E.; Sandoval, Héctor F. Ranea; Berni, M E; Silva, L Da; Henriques, Diamantino; Cussó, F.; Jaqué, F.

doi:10.1088/0022-3727/31/7/010

Cited by 10 publications

(5 citation statements)

References 9 publications

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“…These outcomes would indicate the importance of photoprotective mechanisms at the epilimnetic layers of clear North Patagonian Andean lakes. In particular, Patagonia is an area temporally influenced by the Antarctic polar vortex, and thus affected by low-ozone air masses (Orce & Helbling, 1997;Pe´rez et al, 1998). This situation and the optical and physical lake features would indicate a significant importance of UVR and PAR on the vertical distribution of phytoplanktonic cells in these freshwater systems (Villafan˜e et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Phytoplankton absorption spectra along the water column in deep North Patagonian Andean lakes (Argentina)

et al. 2007

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During a summer period we studied the vertical variation of in vivo and chlorophyll a specific phytoplankton absorption spectra in relation to the underwater light climate of ten deep North Patagonian Andean lakes of Argentina. The lakes were thermally stratified, and the underwater light climate was characterized by extended euphotic zones which included highly illuminated epilimnetic layers (both UVR and PAR) and metalimnia exposed to dim blue-green light. Most of the lakes presented the development of Deep Chlorophyll Maxima (DCM) at the metalimnetic layers, near 1% of surface PAR irradiance. Analyzing the fourth-derivative plots of in vivo phytoplankton absorption spectra [d IV a ph (l)], we were able to identify several maxima absorption values attributed to different pigments. Considering lakes with DCM, a significant positive linear relationship was found between d IV a ph (495-500 nm) normalized by chlorophyll a and downward irradiance. Indeed, a negative significant relationship was found between d IV a ph (495-500 nm) normalized by chlorophyll a and diffuse PAR attenuation coefficients. These results point out an increase in the relative concentration of different carotenoids at surface layers indicating the role of photoprotection of these pigments. On the other hand, significant negative linear relationships were found between fourth-derivative spectra normalized by chlorophyll a at 650, 590-595, 560-565 and 520-525 nm and downward irradiance. These results indicated an increase in the relative concentration of photosynthetic accessory pigments at deep layers of the euphotic zone. Furthermore, we found a decrease in depth of specific absorption spectra at 440, 670 nm and in the ratio a ph * (440 nm) to a ph * (670 nm). This pattern was associated with the package effect concept. The increase in relative photosynthetic accessory pigment concentrations and the decrease in values of specific absorption spectra at the bottom of the euphotic zone were attributed to changes in phytoplankton communities between surface and deep layers. These outcomes pointed out that the underwater light climate and temperature water structure are, like in marine systems, very important factors governing the distribution of phytoplanktonic organisms. ARTICLE IN PRESSwww.elsevier.de/limno 0075-9511/$ -see front matterIn addition, the possession of specific photosynthetic accessory pigments suggests that dominant species in the DCM are well adapted to these dim blue-green light scenarios.

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Section: Discussionmentioning

confidence: 99%

Phytoplankton absorption spectra along the water column in deep North Patagonian Andean lakes (Argentina)

et al. 2007

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“…During early spring, however, there are some days with relatively low ozone concentrations ( i.e. 220–270 DU) that are associated with the Antarctic polar vortex and the ozone “hole.” In fact, several studies have shown the presence of low‐ozone air masses over Patagonia, caused by the Antarctic polar vortex that covers the tip of South America for short periods of time (31,66–73) (Fig. 1) or ozone‐depleted air masses that detach from the polar vortex ( i.e.…”

Section: Atmospheric Characteristicsmentioning

confidence: 99%

“…The extent of the Antarctic ozone “hole” over Patagonia has been determined by different techniques/methodologies such as launching balloons (76), estimations with satellite imagery ( i.e. total ozone mapping spectrometer [TOMS] data from the Goodart Space Flight Center; http://http://jwocky.gsfc.nasa.gov) or using different types of radiometers (63), finding a signal that can be traced as north as 38° S (31,72,73). These studies have highlighted, however, the temporal and spatial variability of low‐ozone air masses over Patagonia.…”

Section: Atmospheric Characteristicsmentioning

confidence: 99%

Impact of Solar Ultraviolet Radiation on Marine Phytoplankton of Patagonia, Argentina^¶

Helbling

Barbieri

Marcoval³

et al. 2005

Photochem & Photobiology

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Patagonia area is located in close proximity to the Antarctic ozone “hole” and thus receives enhanced ultraviolet B (UV‐B) radiation (280–315 nm) in addition to the normal levels of ultraviolet A (UV‐A; 315–400 nm) and photosynthetically available radiation (PAR; 400‐700 nm). In marine ecosystems of Patagonia, normal ultraviolet radiation (UVR) levels affect phytoplankton assemblages during the three phases of the annual succession: (1) prebloom season (late summer‐fall), (2) bloom season (winter‐early spring) and (3) postbloom season (late spring‐summer). Small‐size cells characterize the pre‐and postbloom communities, which have a relatively high photosynthetic inhibition because of high UVR levels during those seasons. During the bloom, characterized by micro‐plankton diatoms, photosynthetic inhibition is low because of the low UVR levels reaching the earth's surface during winter; this community, however, is more sensitive to UV‐B when inhibition is normalized by irradiance (i.e. biological weighting functions). In situ studies have shown that UVR significantly affects not only photosynthesis but also the DNA molecule, but these negative effects are rapidly reduced in the water column because of the differential attenuation of solar radiation. UVR also affects photosynthesis versus irradiance (P vs E) parameters of some natural phytoplankton assemblages (i.e. during the pre‐ but not during the postbloom season). However, there is a significant temporal variability of P vs E parameters, which are influenced by the nutrient status of cells and taxonomic composition; taxonomic composition is in turn associated with the stratification conditions (e.g. wind speed and duration). In Patagonia, wind speed is one of the most important variables that conditions the development of the winter bloom by regulating the depth of the upper mixed layer (UML) and hence the mean irradiance received by cells. Studies on the interactive effects of UVR and mixing show that responses of phytoplankton vary according to the taxonomic composition and cell structure of assemblages; therefore cells use UVR if >90% of the euphotic zone is being mixed. In fact, cell size plays a very important role when estimating the impact of UVR on phytoplankton, with large cells being more sensitive when determining photosynthesis inhibition, whereas small cells are more sensitive to DNA damage. Finally, in long‐term experiments, it was determined that UVR can shape the diatom community structure in some assemblages of coastal waters, but it is virtually unknown how these changes affect the trophody‐namics of marine systems. Future studies should consider the combined effects of UVR on both phytoplankton and grazers to establish potential changes in biodiversity of the area.

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“…Ozone monitoring through ground-based instruments and comparison with data from satellites for midlatitude regions (Balis et al, 2007;McPeters et al, 1998;Keckhut et al, 2010) is essential because, in these densely populated re-gions, phenomena occur such as the formation of mini ozone holes in the Northern Hemisphere (Semane et al, 2002) and events that influence the Antarctic ozone hole (Farman et al, 1985;Solomon, 1999) in the Southern Hemisphere (Kirchhoff et al, 1996;Perez et al, 1998;De Laat et al, 2010;Pinheiro et al, 2012;Schuch et al, 2015). Ozone content exchange between the stratosphere and the troposphere (Holton et al, 1995;Stohl et al, 2003) occurs in both hemispheres (Škerlak et al, 2014) at midlatitudes.…”

Section: Introductionmentioning

confidence: 99%

Measurements of the total ozone column using a Brewer spectrophotometer and TOMS and OMI satellite instruments over the Southern Space Observatory in Brazil

et al. 2017

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Abstract. This paper presents 23 years of quasi-continuous measurements of the total ozone column (TOC) over the Southern Space Observatory (SSO) in São Martinho da Serra, Brazil (29.26 • S, 53.48 • and 488 m altitude). The TOC was measured by a Brewer spectrometer, and the results are also compared to daily and monthly observations from the TOMS (Total Ozone Mapping Spectrometer) and OMI (Ozone Monitoring Instrument) satellite instruments. Analyses of the main interannual modes of variability computed using the wavelet transform method were performed. A favorable agreement between the Brewer spectrophotometer and satellite datasets was found. The seasonal TOC variation is dominated by an annual cycle, with a minimum of approximately 260 DU in April and a maximum of approximately 295 DU in September. The wavelet analysis applied in the SSO TOC anomaly time series revealed that the Quasi-Biennial Oscillation (QBO) modulation was the main mode of interannual variability. The comparison between the SSO TOC anomaly time series with the QBO index revealed that the two are in opposite phases.

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The extent of the ozone hole over South America during the spring of 1993, 1994 and 1995

Cited by 10 publications

References 9 publications

Phytoplankton absorption spectra along the water column in deep North Patagonian Andean lakes (Argentina)

Phytoplankton absorption spectra along the water column in deep North Patagonian Andean lakes (Argentina)

Impact of Solar Ultraviolet Radiation on Marine Phytoplankton of Patagonia, Argentina^¶

Measurements of the total ozone column using a Brewer spectrophotometer and TOMS and OMI satellite instruments over the Southern Space Observatory in Brazil

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The extent of the ozone hole over South America during the spring of 1993, 1994 and 1995

Cited by 10 publications

References 9 publications

Phytoplankton absorption spectra along the water column in deep North Patagonian Andean lakes (Argentina)

Phytoplankton absorption spectra along the water column in deep North Patagonian Andean lakes (Argentina)

Impact of Solar Ultraviolet Radiation on Marine Phytoplankton of Patagonia, Argentina¶

Measurements of the total ozone column using a Brewer spectrophotometer and TOMS and OMI satellite instruments over the Southern Space Observatory in Brazil

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Impact of Solar Ultraviolet Radiation on Marine Phytoplankton of Patagonia, Argentina^¶