Penetration of ultraviolet radiation in the waters of the estuary and Gulf of St. Lawrence

Kuhn, Penny; Browman, Howard I.; McArthur, Bruce; St-Pierre, Jean-François

doi:10.4319/lo.1999.44.3.0710

Cited by 59 publications

(45 citation statements)

References 23 publications

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“…The lowest DOC and chl a values-0.448 g m-3 and 0.05 pg I-', respectively-were measured at Stn S27 (sampled on 15 June 1997). The highest DOC value-3.59 g m-3-was recorded at Stn S21 (sampled on 1 September 1997), and the highest chl a value-2.02 pg l-'-was recorded at Stn S44 (sampled on 30 August 1997) (Kuhn et al 1999). …”

Section: Calanus Eggsmentioning

confidence: 99%

“…However, for most marine water types there is a significant autocorrelation between DOC and chl a, making it difficult to determine their respective contributions to the diffuse attenuation coefficients. However, the slopes of these relationships imply that yellow substance, and therefore DOC, is important (Kuhn et al 1999). Because of the mixed influence chl a and DOC have on UV attenuation in marine waters, seasonal changes in the relative concentrations of these parameters will significantly affect UV penetration.…”

Section: Calanus Eggsmentioning

confidence: 99%

“…Although the variables that affect UV-B attenuation are still under active investigation, particularly in marine environments (e.g. Kuhn et al 1999), dissolved organic carbon (DOC) and chlorophyll a (chl a) appear to be important (Scully & Lean 1994, Morris et al 1995, Laurion et al 1997.…”

Section: Stratospheric Ozone and The Impact Of Ultraviolet Radiationmentioning

confidence: 99%

“…Complete details of the methods used to obtain the optics and water chemistry data are reported in Kuhn et al (1999).…”

Section: Calanus Eggsmentioning

confidence: 99%

“…Spectral downwelling irradiance (290 to 400 nm at a resolution of 1 nm) was collected through the aperture of a submersible integrating sphere attached via a (Kuhn et al 1999).…”

Section: Underwater Opticsmentioning

confidence: 99%

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Impact of ultraviolet radiation on marine crustacean zooplankton and ichthyoplankton:a synthesis of results from the estuary and Gulf of St. Lawrence, Canada

Browman¹,

Rodriguez²,

Béland³

et al. 2000

Mar. Ecol. Prog. Ser.

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The objectives of the research program reported upon here were (1) to measure ambient levels of UV radiation and determine whichvariables most strongly affected its attenuation in the waters of the estuary and Gulf of St. Lawrence, Canada; and (2) to investigate the potential direct impacts of W radiation on species of crustacean zooplankton and fish whose early life stages are planktonic. In this geographic region, productivity-determining biophysical interactions occur in the upper 0 to 30 m of the water column. Measurements of the diffuse attenuation coefficients for ultraviolet-B radiation ( W -B , 280 to 320 nm) at various locations in this region indicated maximum 10% depths (the depth to which 10% of the surface energy penetrates at a given wavelength) of 3 to 4 m at a wavelength of 310 nm. Organisms residing in this layer-including the eggs and larvae of Calanus finmarchicus and Atlantic cod Gadus morhua-are exposed to biologically damaging levels of W radiation. As a result of these physical and biological characteristics, this system offered a relevant opportunity to assess the impacts of UV on subarctic marine ecosystems. Eggs of C. finmarchicus were incubated under the sun, with and without the W -B and/or UV-A (320 to 400 nm) wavebands. W-exposed eggs exhibited low percent hatchmg compared to those protected from W : W radiation had a strong negative impact on C. finmarchicus eggs. Further, percent hatching in W-B-exposed eggs was not significantly lower than that in eggs exposed to UV-A only: under natural sunlight, UV-A radiation appeared to be more detrimental to C. finmarchicus embryos than was UV-B. In analogous experiments with Atlantic cod eggs, exposure to UV-B produced a significant negative effect. However, UV-A had no negative effect on cod eggs. Additional experiments using a solar simulator (SS) revealed high wavelength-dependent mortality in both C. finmarchicus and cod embryos exposed to UV. The strongest effects occurred under exposures to wavelengths below 312 nm. At the shorter wavelengths (<305 nm) UV-B-induced mortality was strongly dose-dependent, but (for both C. finmarchicus and cod) not significantly influenced by dose-rate. Thus, at least within the limits of the exposures under which the biological weighting functions (BWFs) were generated, reciprocity held. The BWFs derived for UV-B-induced mortality in C. finmarchicus and cod eggs were similar in shape to the action spectrum for UV-B effects on naked DNA. Further, the wavelengthdependence of DNA damage was similar to that for the mortality effect. These observations suggest that W-induced mortality in C. finmarchicus and cod eggs is a direct result of DNA damage. There was no evidence of a detrimental effect of UV-A radiation in these SS-derived results. A mathematical model that includes the BWFs, vertical mixing of eggs, meteorological and hydrographic conditions, and ozone depletion, indicates that W-induced mortality in the C. finmarchicus egg population could be as high as 32.5 %, while the impact on the co...

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Section: Calanus Eggsmentioning

confidence: 99%

Section: Calanus Eggsmentioning

confidence: 99%

Section: Stratospheric Ozone and The Impact Of Ultraviolet Radiationmentioning

confidence: 99%

“…Complete details of the methods used to obtain the optics and water chemistry data are reported in Kuhn et al (1999).…”

Section: Calanus Eggsmentioning

confidence: 99%

“…Spectral downwelling irradiance (290 to 400 nm at a resolution of 1 nm) was collected through the aperture of a submersible integrating sphere attached via a (Kuhn et al 1999).…”

Section: Underwater Opticsmentioning

confidence: 99%

See 3 more Smart Citations