Seminario	pdf KB
	1) Maite de los Santos: Photochem. Photobiol. Sci., 2003, 2, 51–61 Interactive effects of ozone depletion and climate change on biogeochemical cycles Richard G. Zepp et al.	331
	2) Claudia: Book Chapter Solar radiation as an ecosystem modulator. R. G. Wetzel (2003)	457
	3) Paola; Freshwater Biology (2003) 48, 108–122 Differential responses to UVR by bacterioplankton and phytoplankton from the surface and the base of the mixed layer MARGUERITE A. XENOPOULOS* and DAVID W. SCHINDLER	582
	4) Leticia Vidal: Limnology and Oceanography (1983) Carotenoid enhancement and its role in maintaining blue-green algal (Microcystis aeruginosa) surface blooms Hans W. Paerl, Jane Tucker, and Patricia T. Bland	1266
	5)Lizet: J. Phycol. 34, 928–938 (1998) ULTRAVIOLET SUNSCREENS IN GYMNODINIUM SANGUINEUM (DINOPHYCEAE): MYCOSPORINE-LIKE AMINO ACIDS PROTECT AGAINST INHIBITION OF PHOTOSYNTHESIS Patrick J. Neale,2 Anastazia T. Banaszak, and Catherine R. Jarriel	200
	6) Britos : Limnol. Oceanogr., 47(6), 2002, 1844–1848 Temperature-dependent ultraviolet responses in zooplankton: Implications of climate change	221
	7) Felo: Nature (2000) Effect of climate change relative to ozone depletion on UV exposure in subarctic lakes Reinhard Pienitz & Warwick F. Vincent	1267

PROGRAMA TEORICO-PRÁCTICO

(6-10 de Diciembre)

Part I: Introduction and basic concepts. Division of the solar spectrum, radiation at the top of the atmosphere and at the ground, spectral irradiance. Biological weighting function and action spectra. Factors affecting the UV climate reaching the Earth’s surface: changes in stratospheric (ozone trends, photochemistry, “miniholes” over South America) and troposheric ozone, solar variability, clouds, aerosols, changes in solar zenith angle. The UV:temperature ratio concept. Altitude effect. Trends in UV radiation at the Earth’s surface. Summary.

Part II: UV in the aquatic medium: reflection and refraction, reflection at the water surface as affected by wind speed, attenuation (Lambert-Bouguert law), measurements of downwelling and scalar irradiance, diffuse or vertical attenuation coefficient (Kd), How to calculate Kd, examples of UV penetration in sediment and water bodies. Inherent and apparent properties of a medium. Attenuation length or transparency. Weighted transparency. Relationship between Kd and absorption. Absorption of PAR and UV radiation by the water itself, humic substances, and seston. Absorption and water color relationship. Secchi depth and UV attenuation relationship. Qualitative vs. quantitative changes of irradiance in the water column. UVB and UVA penetration, Attenuation depth concept, penetration of UVB in different aquatic systems, the concept of physical refuge. Factors controlling the variability of UV attenuation among aquatic systems. Why DOC concentration but also DOM quality matter. Special cases in coastal lagoons and eutrophic lakes. Temporal changes in Kd (role of photobleaching, DOM imputs). Infleunce of phytoplankton in transparent lakes. Summary (4 h).

Part III: DOC, DOM, CDOM and interactions with UVR. Why the C pool is of major importance to aquatic systems? The central role of DOC in freshwater ecosystems. Examples. What is dissolved? Typical DOC values in aquatic systems. Main sources (allochthonous and autochthonous). Which process are important in producing autochthonous DOM? (Marine/lake snow, fecal pellets, gels, extracellular release of DOM by phytoplankton, sloppy feeding of zooplankton, protists grazing, virus mortality). DOC in precipitation. Runoff generation and calculation. Runoff and DOC concentrations in different climate zones. Factors affecting riverine DOC export and concentration (examples on role of soil carbon content, wetlands, vegetation). Changes in DOC concentration across latitude and altitude. DOM composition and structure. Chemical and optical characterization of DOM. Interactions between UV radiation and CDOM. Photoreactions: oxidation and degradation of DOM, loss of dissolved oxygen, formation of low molecular weight organic substances, inorganic species, release of complexed/ bound species, positive feedback of UVR on bacterial growth through photodegradation photobleaching (CDOM absorptivity half-lives, relative contribution of different wavebands, influence of mean lake depth, residence time), photochemical production of reactive oxygen species, Jablonsky diagram, important transient species, hydrogen peroxide. Summary (4 h).

Part IV: Strategies to minimize UV damage in aquatic organisms: behavioral avoidance, outer cover, protective compounds (scytonemin, sporopollenin, melanin, carotenoids, mycosporine-like amino acids or MAAs, mycosporines). Distribution of pigments and UV-absorbing compounds among different aquatic taxa. Tradeoff of pigmentation and predation. Photodynamic effect. Antioxidants substances and enzymes. Ecology of MAAs (synthesis, chemical transformation, bioaccumulation, distribution) UV refuge concept and MAAs. Why not all organisms can accumulate MAAs? Are they more sensitive to UV? MAAs versus carotenoids accumulation in zooplankton. MAAs in bloom-forming cyanobacteria. Physiological constraints of MAAs synthesis in relation to cell size. Other strategies (colony formation). Symbiosis and UV protection. DNA damage and mechanisms of repair. Role of temperature: cold temperatures means higher UV sensitivity? Summary (4 h).

Part V: Effects of UV radiation I. UVB effects at different organization levels. Alternate mechanisms for solar UV radiation to damage cellular material. How to study the effect of UVR on aquatic organisms? Examples of effects on primary producers. Seasonal dynamics and UV sensitivity (UV as another environmental parameters affecting organisms distribution). Examples of complex effects: benthic microalgae and insect larvae interactions. Effect on aquatic viruses (Role of A+T content in DNA). Heterotrophic bacteria and microalgae interactions. Heterotrophic flagellates and heterotrophic bacteria interactions. DNA damage among different protozoans, Long-term effects on heterotrophic flagellates. Effect on bacterivory. Effects on macrozooplankton (taxa- and species-specific sensitivity, photorepair capacity). Does UV sensitivity of zooplankton determine the type of lake they can colonize? (example of a deglaciation chronosequence). Effect on fish larvae and adults (sunburn, deformations). Sublethal effects. Indirect effects of UVB radiation (trophic interactions). Phototoxicity of UV and pollutants (why is necessary to consider solar UV radiation in toxicity tests?).

Part VI: The effect of UV radiation: synergistic and antagonistic processes of the climatic change. What is and how is defined “Climatic change”? Greenhouse gases and climatic warming. Climatic warming= Global warming? Cooling in some parts of the Earth. Ecological consequences for aquatic ecosystems. Some examples. Connection between climatic warming and UV stress in different aquatic systems. What matters more to aquatic ecosystems? ozone depletion or climatic warming effects on the concentration of colored dissolved organic matter Droughts and floods. Importance of ENSO for Uruguay. Climatic changes already detected in Uruguay? What scenarios of temperature and precipitation changes do climatic models forecast for Uruguay? Potential changes in aquatic ecosystems under warm-dry and warm-wet scenarios.
Dias 13-14: Seminarios y discusión crítica de publicaciones. Los temas de las publicaciones se distribuirán durante el curso en base en lo posible al interés de los participantes.

Dia 15/12: Salida de campo (mediciones y experimentos in situ si el tiempo acompaña...)

Dias 16-17: Análisis de muestras y datos.

Dia 18/12: Presentación de resultados y exámen.

Dias 13-14-16-17 : Consulta particular de estudiantes de posgrado.

INSCRIPCIONES: En la Secretaría Académica del PEDECIBA Biología, Facultad de Ciencias, teléfono 5258629, e-mail pedebiol@fcien.edu.uy