2009 Annual Science Report

University of Hawaii, Manoa Reporting  |  JUL 2008 – AUG 2009

Executive Summary


Water is the medium in which the chemistry of all life on Earth takes place. It is likely to be equally important for Astrobiology in general. It is the theme we chose for the first five years of the University of Hawai’i (UH) NAI (CAN 3) and it is the theme we proposed for CAN5. Like our earlier effort, this proposal combines a set of studies that range from the interstellar medium to the interior of planet Earth, all designed to elucidate “the origin, history, and distribution of water and its relation to life in the Universe”, and the relation to Habitable Worlds. However, our focus has changed to highlight those areas of research which can make the most use of interdisciplinary approaches. The research areas are as follows:

* We don’t know where the water on Earth came from. It may be that the ... Continue reading.

Field Sites
35 Institutions
47 Project Reports
59 Publications
21 Field Sites

Project Reports

  • Detection of Planets Around M-Dwarfs

    In the studies of extrasolar planets, the nearest stars are of particular importance. We have started a survey of nearby M dwarfs in search of terrestrial planets.Our program has been responsible for the discovery of many planets around M dwarfs for the past several years, including the most recent one which is a Saturn-mass object. Our project is continuing and we expect more discovery of small planets in the next year.

  • Terrestrial and Habitable Planet Formation in Binary Stars

    We are studying the formation of Earth-like/habitable planets in binary star systems, in particular those that host a giant planet. We are simulating the formation of these bodies for different distribution of water in a circumstellar disk. With more than 50% of stars in binary systems, it is quite possible that Kepler space telescope may soon find many of such binary-planetary systems.

  • Rare Subduction Zone Carbonate Mineral May Hold Clues to Early Life

    Recent work performed by Erik Melchiorre as part of a NASA Minority
    Institution Research Sabbatical indicates that the rare purple mineral
    stichtite Mg6Cr2[(OH)16|CO3] . 4H2O may provide a record of
    the carbon, hydrogen and ocygen isotope values of serpentizing fluids
    from ancient subduction zones. This could be of significant interest
    in the study of methane signatures on Mars, as well as the study of
    early life on Earth.

    ROADMAP OBJECTIVES: 4.1 4.3 7.1 7.2
  • Detection of Super-Earths Using Transit Timing Variation Method

    Jupiter-like planets may orbit their parent stars in very close distances and reduce their brightness by blocking some of their lights. A second planets with a mass several times more than the Earth in such systems can disturb the orbit of the Jupiter-like planet and causes its transit to occur at different times. By measuring the time between these transit we can determine the size and orbit of the perturbing planet.

  • Nordic-UHNAI Astrobiology Summer School – Iceland 2009

    In collaboration with the Nordic Astrobiology Network, we organized an astrobiology summer school held in Iceland from Jun 29-Jul 13, 2009. Participants included 19 graduate students from the US, and 24 students from 16 countries, with a focus on Nordic participants. Activities during the two week program included lectures on the topics of Water, Ice and the Origin of Life in the Universe, a student poster session, field sampling on thermophiles, and labwork and computer modeling activities.

    ROADMAP OBJECTIVES: 2.2 3.1 5.2 5.3
  • Origin of the Parent Bodies of Iron Meteorites and Constraint on Giant Planet Formation

    Understanding the origin of the parent bodies of iron meteorites is essential to the theories of planet formation. These objects are formed less then two million years after the formation of the first bodies in the solar system. As a result understanding their formation may reveal clues to the time of the formation of giant planet. We are continuing our project on this topic, and are studying the effects of the growth of giant planets on the dynamics of planetesimals, and their chosmochemical properties.

  • Giant Planet Formation (Late Stage of the Formation of Jupiter)

    Measurements of the abundance of elements in Jupiter’s atmosphere have indicated that high-density materials are several times more abundant in Jupiter’s envelope than in the Sun. To understand the reason for this anomaly, we have started a project on the interactions of planetesimals with Jupiter’s gaseous envelope at the last stage of the formation of this planet.
    Results indicate that the deposition of sublimated materials from planetesimals due to gas drag can in crease the metalicity giant planets.

  • Main Belt Comet Origin, Formation and Activation

    Main Belt Comets are a new class of objects that have recently been detected in the asteroid belt. These objects carry sub-surface water ice that may have played an important role in the delivery of water to the Earth. This project aims to understand the origin of MBCs, their contribution to Earth’s water budget, and the regions in the asteroid belt where many of these bodies can be found.

  • Keck Astrochemistry Laboratory

    The overall goal of this project is to comprehend the chemical evolution of the Solar System. This will be achieved through an understanding of the formation of carbon-, hydrogen-, oxygen-, and nitrogen-bearing (CHON) molecules in ices of Kuiper Belt Objects (KBOs) by reproducing the space environment in a specially designed experimental setup. KBOs are small planetary bodies orbiting the sun beyond the planet Neptune, which are considered as the most primitive objects in the Solar System. A study of KBOs is important because they resemble natural ‘time capsules’ at a frozen stage before life developed on Earth. Our methodology is based on a comparison of the molecules formed in the experiments with the current composition of KBOs; such approach provides an exceptional potential to reconstruct the composition of icy Solar System bodies at the time of their formation billions of years ago. The significance of this project is that our studies elucidate the origin of biologically relevant molecules and help unravel the chemical evolution of the Solar System. Since KBOs are believed to be the main reservoir of short-period comets, which are considered as ‘delivery systems’ of biologically important molecules to the early Earth, our project also brings us closer to the understanding of how life might have emerged on Earth.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2
  • Modelling Grain Surface Chemistry in Dense Clouds

    Dust grains in interstellar molecular clouds accrete molecules from the gas,
    resulting in the growth of ice mantles that eventually get
    transported into the protostellar environment. It is here, that the
    warm and dense environments of star forming regions promote a rich
    chemistry that creates complex prebiotic compounds and a small
    fraction of this material ends up as planets. Quantifying the level of molecular complexity attainable through dust grain surface chemistry requires modeling the key
    hydrogenation and oxidation chemical pathways.

  • PanSTARRS MBC Stamp Server and Detection Limits

    We have been developing the architecture to search for main belt comets (MBCs) in the upcoming Pan-STARRS1 all sky survey. MBCs are an important new reservoir of water in the inner solar system, and we hope to be detecting a steady stream of them in PS1 beginning in late 2009 or early 2010.

    ROADMAP OBJECTIVES: 1.1 2.2 6.2
  • Irradiation of Lunar Samples

    We are irradiating silicate samples with 1 keV energetic protons (H+) to simulate weathering of silicate rocks on the moon from the solar wind. Here, the goal is to demonstrate the production of water through interaction of the impinging particles with oxygen atoms within the silicate material. This should help explain the recent discoveries from the Indian Chaandrayan-1 spacecraft mission which recently discovered water within the upper layers of the surface.

  • Ultra-Violet Processing of Ices in the Rosette Molecular Cloud

    Ices and organics in the molecular clouds are subjected to a plethora of harsh conditions such as thermal, ultraviolet- (UV), and particle-irradiation that destroy, sputter or modify the material. As a result, it is likely that the molecular compounds found in the initial cloud and those observed in circumstellar disks may not, at first glance, be very similar but instead are linked via complex chemical networks. the Sun formed in a high mass star-forming cloud where at least one, and most likely many, supernova events occurred, resulting in intense UV radiation throughout the cloud complex. The Rosette molecular cloud provides the perfect laboratory analog for the early solar nebula molecular cloud. This project is a comparative study of the UV processing of the ices toward several embedded stellar clusters in the Rosette molecular cloud.

  • Comet Holmes

    We observed the outburst of Comet Holmes. Using image processing techniques, we inferred the existence of a large number of distinct fragments or subnuclei ejected at a velocity of 100 meters per second. We deduced that these subnuclei may consist of clusters of small particles, and were most likely expelled by a very efficient gas ejection process.

  • VYSOS Construction

    The VYSOS project aims at surveying all the major star forming regions
    all across the entire northern and southern sky for variable young
    stars. Two small survey telescopes have been purchased and provide
    large area shallow observations, and two larger telescopes allow
    deeper more detailed observations. All observations are done

    ROADMAP OBJECTIVES: 1.1 1.2 2.2
  • Light Curve of Main Belt Comet 176P/LINEAR

    Comet 176P/Linear belongs to the new class of main belt comets (MBCs) which show both, asteroid and comet like behavior. As these solar system bodies reside in the asteroid belt between Mars and Jupiter, they are easier to reach for a spacecraft compared to comets in the Oort cloud or the Kuiper belt. We are proposing a NASA Discovery-Class mission to such a main belt comet. Currently only four MBSs are known and it is crucial that we learn as much as possible about their physical properties. The aim of this project is to obtain a rotational light curve from recent observations with the UH2.2m telescope on Mauna Kea. The light curve will allow us to determine the how fast the comet’s nucleus is rotating.

  • Permafrost in Microclimates

    Microclimates are small areas where climate conditions differ from the surrounding area. This can lead to the occurrence of permafrost in otherwise ice-free areas or to exceptionally long lasting ice. The reasons for the persistence of the ice or its age are inadequately understood. In this project, two study sites are investigated. One is an exceptionally old glacial remnant in Upper Beacon Valley, Antarctica. Paradoxically, tiny amounts of melt water may play a crucial role in the survival of the ice. The second study area includes extremely rare patches of permafrost on the Hawaiian Islands, in cinder cones near the summit of Mauna Kea.

  • Mars Bulk Composition

    The bulk composition of Mars, including its total inventory of water, is central to understanding how planets form and to fully understanding the role of water in Martian geological evolution.

  • Lunar Differentiation

    Jeff Taylor with his colleague Linda Martel have been studying the genesis of highly differentiated lunar rocks. These give insight into the early stages of crust formation and provide a framework for understanding similar rocks from Vesta and Mars. They have been focusing recently on the chemical and mineralogical differences among KREEP basalts, which are characterized by enrichments in K, Rare Earth Elements, and Phosphorus.

  • Chemistry, Origin and Evolution of Subduction Zone Fluids Rising Beneath the Mariana Forearc

    Ultramafic rocks make up the mantle of most rocky bodies in the Solar System. When ultramafic rocks come in contact with liquid water they are altered to serpentinite over a wide range of temperatures, from freezing to about 500ºC. On Earth, plate tectonics provides ample opportunity for this contact to occur, especially in subduction zones. In extraterrestrial environments, serpentinization should occur wherever liquid water comes into contact with mantle-type rocks, such as on Mars and on the parent bodies of asteroids. We have collected waters upwelling through serpentinite mud volcanoes in the forearc region of the Mariana subduction zone in the NW Pacific Ocean. These waters are rich in methane produced inorganically during serpentinization. The methane supports chemosynthetic communites of extremophilic Archaea that thrive at an in-situ pH of 13.1.

  • Mineral-Catalyzed Coupling of Amino Acids to Polypeptides

    Enzymes carry out chemical functions within our body, and are produced from long chains of amino acids called polypeptides. Today, the manufacture of these long chains is made possible within our bodies by large 'machinery’ known as polymerases. However, these are vastly complex, and were almost certainly not present in the early stages of life. One question we are trying to answer here is whether or not it is possible to produce long chains of polypeptides under certain conditions which may be relevant to the origin of life, such as on the surface of a mineral.

    ROADMAP OBJECTIVES: 3.1 3.2 7.1 7.2
  • Main Belt Comet P/2008 R1 Garradd Characterization

    We identified P/2008 R1 as a main-belt comet (previously mis-classified as an ordinary Jupiter-family comet) and mounted an observational program to assess its physical properties, and a dynamical campaign to understand its orbit.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Deep Biosphere Workshop

    This is a Workshop on the use of borehole CORK observatories for microbiological and hydrogeological studies. It is planned to be an international workshop including European and Asian participation. We are also actively targeting early career researchers and those not yet actively involved in deep marine CORK observatory research.

    ROADMAP OBJECTIVES: 4.2 5.2 5.3 6.1 6.2
  • Formation of Carbon and Nitrogen-Rich Organics in Solar System Ices

    carbon and nitrogen-rich organics are essential to life as we know it, but how readily available were they on the primordial earth? clues about the composition of primordial material thar could be present come from irradiation experiments on the precursors already identified on interstellar ices

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2
  • Hydrogen in Nominally Anhydrous Minerals

    The amount of water in the Earth’s interior is not known. Experiments have shown that at high pressure, the high-pressure forms of the minerals that make up the Earth’s mantle can contain significant hydrogen substituting for magnesium. We are carrying out a series of experiments to determine how much hydrogen (=water) can be contained in these high-pressure minerals. Mineral samples produced at mantle pressures in the presence of water are being measured using the Cameca ims 1280 ion microprobe at the Unversity of Hawaii to determine the maximum amount of water that each mineral can hold at high pressure, providing a constraint on the possible water content of the mantle.

  • D/H Measurements in Samples From Mantle Hotspots

    The origin of Earth’s water is an open question. We are trying to constrain the origin of Earth’s water by measuring the D/H ratios of glass inclusions inside olivine grains from lavas erupted at the Hawaiian and Icelandic hot spots. The hope is that these glass inclusions retain hydrogen from the deep mantle of the Earth, hydrogen that may preserve the original hydrogen isotopic composition of the Earth.

  • Amino Acid Alphabet Evolution

    All life on earth uses a standard “alphabet” of just 20 amino acids. Members of this alphabet links together into different sequences to form proteins that then interact to produce living metabolism (rather like the English of 26 letters can be linked into words that interact in sentences and paragraphs to produce meaningful writing). However, a wealth of scientific research from diverse disciplines points to the idea that many other amino acids are made by non-biological processes throughout the universe: put simply, we have no idea why life has “chosen” the members of its standard alphabet. Our project seeks to gather and organize the disparate information that describes these non-biological amino acids, to understand their properties and potential for making proteins and thus to understand better whether the biology that we know is a clever, predictable solution to making biology – or just one of countless possible solutions that may exist elsewhere.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2 3.4 4.1 4.3 5.1 5.3 6.2 7.1 7.2
  • CASS Planning

    The computational astrobiology summer school (CASS) is a two week program, followed by a semester of mentored independent work, which has the following goals:

    - To introduce computer science and engineering (CS&E) graduate students to the field of astrobiology, – To introduce astrobiologists to the tools and techniques that current methods in CS&E can provide, and – To encourage interdisciplinary projects that will result in advances in astrobiology.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 3.3 3.4 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Lau Basin Cruise

    This project revolves around a volcanic eruption at the seafloor at about 1400 m depth. We responded to this eruption using a research ship, the RV Thompson, and the unmanned remotely operated underwater vehicle, JASON. We used the JASON to sample the fluids and rocks associated with the still active eruption to study the microbial ecology and geochemistry of early life at new eruptive sites.

  • MBC Mission Development

    The distribution of water and volatiles in our solar system may be a primary determinant of solar system habitability. Main Belt Comets (MBCs), a newly discovered class of volatile-containing objects in the asteroid belt, present a sub-class of particular significance both to the water history, and to the history of other important volatiles in our solar system. As comets in near-circular orbits within the asteroid belt, these objects may harbor water condensed and frozen out from the primordial ‘snow line’ of the young solar system. Studying MBC water and volatile inventory will advance our understanding of both the origin of Earth’s ocean and of volatile inventories throughout the Solar System. The UH NAI team is developing a concept for a Discovery class mission to study the Main Belt Comets.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Bioastronomy 2007 Meeting Proceedings

    The 9th International Bioastronomy coneference: Molecules, Microbes and Extraterrestrial Life was organized by Commission 51 (Bioastronomy) of the International Astronomical Union, and by the UH NASA Astrobiology team. The meeting was held in San Juan, Puerto Rico from 16-20 July 2007. During the reporting period the Proceedings were finalized and will have a publication date of 2009.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 3.3 3.4 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Distant Comet Activity

    Observations of comets coming in to the solar system for the first time show that they are very active at distances beyond where water ice sublimation can create outgassing. Understanding the processes that drive comet activity provides us with an understanding of the comet chemistry and allows a glimpse at conditions in the early solar system. Comets impacted the early earth and delivered water, other volatiles and organic materials to the planet, including the ingredients necessary for life. Understanding the chemical and physical make up of comets is important for unraveling the story of what makes a world habitable.

  • Planning for Analogue Environment Deployments With the Canadian Space Agency

    Kim Binsted is on secondment at the Canadian Space Agency, working on an analogue deployment to a site on the slopes of Mauna Kea for Jan/Feb 2010.

  • Quantification of the Disciplinary Roots of Astrobiology

    The questions of astrobiology span many scientific fields. This project analyzes databases of scientific literature to determine and quantify the diverse disciplinary roots of astrobiology. This is one component of a wider study to build a map of relationships between the constituent fields of astrobiology, so relevant knowledge in diverse fields can be most efficiently inform the study of life in the universe.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 3.3 3.4 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Stardust NExT and EPOXI Mission Observing Coordination

    The StardustNExT and EPOXI missions are extended missions to comets, scheduled to arrive on Feb. 14, 2011 and Nov. 4, 2010, respectively. Members of the UH NAI team have been participating in an international observing campaign designed to characterize the nuclei of comets 9P/Tempel 1 and 103P/Hartley 2 in advance of the encounter. In particular, during this reporting period preparation for observations and analysis of the rotation rates of the comets was undertaken.

  • TALCS Survey and MBCs

    We have performed an automated search of the Thousand Asteroid Light Curve Survey (TALCS) for evidence of Main Best Comets (MBCs). We looked for both comae and tails using specially developed automated image processing techniques. Neither approach found any clear MBC candidates, although there was an unexplained excess of diffuse light in the same as a whole.

  • Developing New Sampling System, Collection of Juan De Fuca Ridge Basement Fluids

    Our Deep Biosphere project is designed to exploit the unprecedented opportunities provided by the new generation of long-term borehole- observatories installed on the flanks of the Juan de Fuca Ridge (JdFR) by the Integrated Ocean Drilling Program, to study the microbial geochemistry and ecology of the sediment-buried ocean basement. The Drill ship drills deep holes through the sediments into the underlying basaltic rocks and then installs a 'CORK’ observatory consisting of casings, fluid delivery lines with seafloor access-spigots, downhole instruments, and a top plug.

    ROADMAP OBJECTIVES: 3.2 3.3 4.1 5.2 5.3
  • AIRFrame Technical Infrastructure and Visualization Software Evaluation

    To create visualizations of interdisciplinary relationships in the field of astrobiology, this component of the AIRFrame project involves creating a data model for source documents, a database structure, and evaluating off-the-shelf visualization software for possible application to the final project.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 3.3 3.4 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Analytical and Theoretical Studies on Origin of Earth’s Oceans and Atmosphere

    Origin of Earth’s oceans and atmosphere is an outstanding problem in Earth science. Given the importance of the oceans and atmosphere to Earth’s habitability, it is a critical question for astrobiology as well. Did these features of our planet, so critical for life, originate by regular processes that are likely to be duplicated frequently in other stellar systems, or was there a large element of chance involved? We are approaching this problem by investigating the occurrence of water in the interstellar medium, in the early solar system, and in the deep Earth, using a variety of chemical and isotopic techniques to characterize Earth’s water and to identify the processes that brought it here.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2
  • Characterizing Formation Pathways for 1st Generation Ices

    Molecular chemistry can provide insight into the physical processes at the earliest stages of star birth, when molecular cloud cores collapse to form protostellar condensations. Dust particles in the dense clouds accrete molecules from the gas, resulting in the growth of ice mantles that eventually get transported into the protostellar environment. It is here, that the warm and dense environments of star forming regions promote a rich chemistry that creates complex prebiotic compounds and a small fraction of this material ends up as planets. Understanding the dominant chemical pathways and the composition of the first ice mantles formed in starless molecular
    clouds allows to better interpret the physical effects of star formation (i.e., temperature, radiation, etc.) on molecular cloud material.

  • Comet Kopff Thermal Modelling

    We examine the behavior of a typical comet, designated 22P/Kopff, as it orbits the Sun. When the comet approaches the minimum distance form the Sun, a heat wave penetrates from the surface inwards. This input of heat causes the material to change. These changes invoke an outflow of various gases and solids, which are responsible for the patterns of activity, visible as a coma and tail.

  • Deuteration on Grain Surfaces

    The gas and dust in the interstellar medium undergoes considerable processing in the passage through a cold molecular cloud to a circumstellar envelope to protoplanetary disk to, ultimately, comets and planetesimals. Over the years, deuterium fractionation has been instrumental in deciphering the chemical routes in molecular clouds. Deuterated molecules have a highly temperature-sensitive chemistry and can provide valuable information on physical conditions in the early solar nebula. At low temperatures, the abundance of certain deuterium-bearing species is enhanced by many orders of magnitude. Understanding the discrepancy between the D/H ratio in comets and Earth’s oceans requires better knowledge of grain surface chemistry involving deuterium.

  • Formation of Higher Carbon Oxides in CO2 Rich Solar System Ices

    The interstellar medium contains large dark cold clouds which are full of sub-micrometer interstellar grains. These icy grains are found to contain large amounts of both carbon monoxide and carbon dioxide, however only carbon monoxide is found to be abundant in the gas phase. It is therefore likely that the production of carbon dioxide occurs through the processing of condensed carbon monoxide with irradiation from high energy cosmic rays. It is also likely that more exotic carbon oxides can be produced in this manner, a number of which have been detected for the first time as part of our studies.

  • Infrared Spectra and Radiation Processing of Water- and Ammonia Rich Solar System Ice

    Ammonia has been found in the atmospheres of Jupiter, Saturn, Uranus, and Neptune. In comets and interstellar ices, ammonia is present at around 1% abundance relative to water ice. Ammonia is a potentially important chemical component in the solar system both as a repository of nitrogen in primitive objects such as the nuclei of comets and as an agent by which ice convection can be enhanced in the deep interiors of ice-rich bodies. The spectra obtained in our experiments might be useful for comparison with astronomical observations to estimate the concentration of ammonia in outer solar system ices.

  • Kavli Symposium (Fall 2008)

    The Kavli Frontiers of Science symposia are jointly sponsored by the Kavli Foundation and the US National Academy of Sciences to bring together top young scientists in an interdisciplinary conference environment that encourages in-depth discussions related to exciting advances in the fields of astronomy and astrophysics, computer sciences, neurosciences and physics. As a Kavli fellow, and participant in these seminars, the UHNAI PI has organized a special astrobiology session at the fall 2008 Kavli symposium on the topic of Extrasolar planets, drawing participants from within the NAI. The purpose is to highlight the cutting edge science that is being accomplished in astrobiology through the NAI.

    ROADMAP OBJECTIVES: 1.2 6.2 7.2
  • Mechanisms of Marine Microbial Community Structuring

    The sub-tropical open ocean is an extreme environment that presents the opportunity to examine the factors affecting microbial community structure across a number of environmental gradients. We have developed and utilized a novel assay that allows us to simultaneously determine the taxonomic composition of Archaea, Bacteria and microbial Eucarya in DNA extracted from environmental samples. Samples analyzed represent the epi-, meso- and bathy-pelagic zones of the ocean, which display gradients in temperature, pressure, oxygen content, nutrient content and photosynthetically available radiation.

  • Microbial Ecology in Hawaiian Lava Caves

    We have been studying a microbial biofilm growing at very low light intensities and high temperature and humidity below the entrance of a lava cave in Kilauea Crater, Hawai’i Volcanoes National Park. The cave presents an oligotrophic environment, but condensation of geothermally heated groundwater that vents at the rear of the cave has promoted the development of a complex microbial community, similar in higher order taxonomic structure to copiotrophic soil environments. Given the existence of lava tubes of similar geologic composition on Mars, geothermal activity there may have allowed the existence, or persistence, of complex microbial communities in similar Martian environments, wherein they would be shielded from the effects of harmful UV radiation.