DOCSLIB.ORG

Is the Schwabe Organ a Retained Larval Eye?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Is the Schwabe Organ a Retained Larval Eye? Is the Schwabe organ a retained larval eye? Anatomical and behavioural studies of a novel sense organ in adult leptochiton asellus (Mollusca, Polyplacophora) indicate links to larval photoreceptors Sumner-Rooney, L. H., & Sigwart, J. D. (2015). Is the Schwabe organ a retained larval eye? Anatomical and behavioural studies of a novel sense organ in adult leptochiton asellus (Mollusca, Polyplacophora) indicate links to larval photoreceptors. PLoS ONE, 10(9), [e0137119]. https://doi.org/10.1371/journal.pone.0137119 Published in: PLoS ONE Document Version: Publisher's PDF, also known as Version of record Queen's University Belfast - Research Portal: Link to publication record in Queen's University Belfast Research Portal Publisher rights © 2015 Sumner-Rooney, Sigwart. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made to ensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws. If you discover content in the Research Portal that you believe breaches copyright or violates any law, please contact [email protected]. Download date:27. Sep. 2021 RESEARCH ARTICLE Is the Schwabe Organ a Retained Larval Eye? Anatomical and Behavioural Studies of a Novel Sense Organ in Adult Leptochiton asellus (Mollusca, Polyplacophora) Indicate Links to Larval Photoreceptors Lauren H. Sumner-Rooney1,2*, Julia D. Sigwart1,2 1 School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland, 2 Queen’s Marine a11111 Laboratory, Queen’s University Belfast, Portaferry, Northern Ireland * [email protected] Abstract OPEN ACCESS The discovery of a sensory organ, the Schwabe organ, was recently reported as a unifying Citation: Sumner-Rooney LH, Sigwart JD (2015) Is feature of chitons in the order Lepidopleurida. It is a patch of pigmented tissue located on the Schwabe Organ a Retained Larval Eye? the roof of the pallial cavity, beneath the velum on either side of the mouth. The epithelium is Anatomical and Behavioural Studies of a Novel densely innervated and contains two types of potential sensory cells. As the function of the Sense Organ in Adult Leptochiton asellus (Mollusca, Schwabe organ remains unknown, we have taken a cross-disciplinary approach, using ana- Polyplacophora) Indicate Links to Larval Photoreceptors. PLoS ONE 10(9): e0137119. tomical, histological and behavioural techniques to understand it. In general, the pigmenta- doi:10.1371/journal.pone.0137119 tion that characterises this sensory structure gradually fades after death; however, one Editor: Joseph Clifton Dickens, United States particular concentrated pigment dot persists. This dot is positionally homologous to the lar- Department of Agriculture, Beltsville Agricultural val eye in chiton trochophores, found in the same neuroanatomical location, and further- Research Center, UNITED STATES more the metamorphic migration of the larval eye is ventral in species known to possess Received: March 23, 2015 Schwabe organs. Here we report the presence of a discrete subsurface epithelial structure Accepted: August 12, 2015 in the region of the Schwabe organ in Leptochiton asellus that histologically resembles the chiton larval eye. Behavioural experiments demonstrate that Leptochiton asellus with intact Published: September 14, 2015 Schwabe organs actively avoid an upwelling light source, while Leptochiton asellus with Copyright: © 2015 Sumner-Rooney, Sigwart. This is surgically ablated Schwabe organs and a control species lacking the organ (members of an open access article distributed under the terms of < the Creative Commons Attribution License, which the other extant order, Chitonida) do not (Kruskal-Wallis, H = 24.82, df = 3, p 0.0001). We permits unrestricted use, distribution, and propose that the Schwabe organ represents the adult expression of the chiton larval eye, reproduction in any medium, provided the original being retained and elaborated in adult lepidopleurans. author and source are credited. Data Availability Statement: All relevant data are within the paper. Funding: The authors received no specific funding for this work. A PhD studentship for LHSR was Introduction provided by DEL Northern Ireland (http://www.delni. gov.uk). These funders had no role in study design, Chitons (Mollusca, Polyplacophora) have a flattened, ovoid body with a muscular foot pro- data collection and analysis, decision to publish, or tected by eight dorsal shell valves. The chiton nervous system is considered to represent the ple- preparation of the manuscript. siomorphic condition amongst molluscs, lacking discrete ganglia and with few advanced PLOS ONE | DOI:10.1371/journal.pone.0137119 September 14, 2015 1/11 Is the Schabe Organ a Larval Eye? Competing Interests: The authors have declared sensory organs [1,2]. A previously unknown sensory organ, the Schwabe organ, has recently that no competing interests exist. been discovered and described throughout one of the two taxonomic orders of chitons [3]. This is as a stripe of brownish pigmentation, visible to the naked eye, which extends posteriorly and laterally from either side of the mouth towards the top of the foot (Fig 1A and 1B). The pigmented epithelium is innervated by bundles of nerve fibres and contains multiciliary cells and round basal cells with epithelial projections, both of which could be sensory [3]. However, no specialised structures are visible to surface examination by SEM, and the function of the Schwabe organ remains unknown. Though chitons do not possess cephalic eyes, all members of the class (both taxonomic orders) have specialised pores in their dorsal shells, the aesthetes [4]. In many species, the aes- thetes contain photoreceptors and mediate negative light response behaviour, though the func- tion has never been documented for members of Lepidopleurida [4–9]. Larval development has been described for relatively few species of chitons, including only two species in the order Lepidopleurida: Leptochiton asellus [10] and Lepidopleurus cajetanus [11]. For all species where early ontogeny has been described, chiton trochophore larvae pos- sess larval eyes (Fig 1C). These are post-trochal pigmented photosensitive organs that are thought to contribute to the settlement behaviour of larvae, as several species’ larvae are nega- tively phototactic [12]. Chitons undergo metamorphosis from trochophore to adult form dur- ing settlement, forming a ventral foot and dorsal shell fields. Several authors have described the anatomical migration of the apical larval eyes to the dorsal side during metamorphosis, before they become covered by the growing shell field [reviewed in 12]. Heath [13] noted the persis- tence of the larval eye pigment and suggested it remained a functional eye for as long as it was visible at the dorsal side in developing and early post-metamorphic animals. The eye is ven- trally visible for some time in species in Chitonida [14], and Kowalevsky [15] described the eye sinking beneath the epithelium and persisting to adulthood in Chiton polii. However, clear ven- tral migration of the larval eye has only been reported in Leptochiton asellus [10]; Naef’s draw- ings of Lepidopleurus cajetanus larvae are ambiguous in this respect [11]. This ventral migration in Lepidopleurida results in the larval eye attaining a position reminiscent of the Schwabe organ in adults (Fig 1D). In fact this similarity is not just superficial, but is also reflected in the neuroanatomy. The position of the Schwabe organ is ventral to the lateral nerve cord, and slightly lateral and posterior to the origin of the first lateropedal connective [3; Fig 1F], corresponding precisely to the location of the larval eye [13; Fig 1E]. Sigwart et al. [3] described a bleaching effect that occurs in the pigmented region of the Schwabe organ and speculated this bleaching explained why the sense organ had not been described historically. Further observations of fixed specimens of Leptochiton asellus show that even when most of the pigment has faded, there is a small dot of dense pigment that persists (Fig 1A and 1B). In Leptochiton asellus this dot is found anterior to the centre of the Schwabe organ sunken beneath the surface, and in live animals appears to contain more concentrated pigmentation, suggesting it is an important component of the Schwabe organ. Determining the function of a sensory structure such as the Schwabe organ presents numer- ous challenges that can be managed in a number of ways; structurally (using anatomical or developmental observations) or functionally (directly demonstrating the use of the Schwabe organ through behavioural responses). Here, we combine these techniques in order to further explore the possibility of a link between the Schwabe organ and the larval eye. PLOS ONE | DOI:10.1371/journal.pone.0137119 September 14, 2015 2/11 Is the Schabe Organ a Larval Eye? Fig 1. The Schwabe organ in Leptochiton asellus and the
Load more

Recommended publications
  • Marine Invertebrate Field Guide
    Marine Invertebrate Field Guide Contents ANEMONES ....................................................................................................................................................................................... 2 AGGREGATING ANEMONE (ANTHOPLEURA ELEGANTISSIMA) ............................................................................................................................... 2 BROODING ANEMONE (EPIACTIS PROLIFERA) ................................................................................................................................................... 2 CHRISTMAS ANEMONE (URTICINA CRASSICORNIS) ............................................................................................................................................ 3 PLUMOSE ANEMONE (METRIDIUM SENILE) ..................................................................................................................................................... 3 BARNACLES ....................................................................................................................................................................................... 4 ACORN BARNACLE (BALANUS GLANDULA) ....................................................................................................................................................... 4 HAYSTACK BARNACLE (SEMIBALANUS CARIOSUS) .............................................................................................................................................. 4 CHITONS ...........................................................................................................................................................................................
    [Show full text]
  • The Biology of Seashores - Image Bank Guide All Images and Text ©2006 Biomedia ASSOCIATES
    The Biology of Seashores - Image Bank Guide All Images And Text ©2006 BioMEDIA ASSOCIATES Shore Types Low tide, sandy beach, clam diggers. Knowing the Low tide, rocky shore, sandstone shelves ,The time and extent of low tides is important for people amount of beach exposed at low tide depends both on who collect intertidal organisms for food. the level the tide will reach, and on the gradient of the beach. Low tide, Salt Point, CA, mixed sandstone and hard Low tide, granite boulders, The geology of intertidal rock boulders. A rocky beach at low tide. Rocks in the areas varies widely. Here, vertical faces of exposure background are about 15 ft. (4 meters) high. are mixed with gentle slopes, providing much variation in rocky intertidal habitat. Split frame, showing low tide and high tide from same view, Salt Point, California. Identical views Low tide, muddy bay, Bodega Bay, California. of a rocky intertidal area at a moderate low tide (left) Bays protected from winds, currents, and waves tend and moderate high tide (right). Tidal variation between to be shallow and muddy as sediments from rivers these two times was about 9 feet (2.7 m). accumulate in the basin. The receding tide leaves mudflats. High tide, Salt Point, mixed sandstone and hard rock boulders. Same beach as previous two slides, Low tide, muddy bay. In some bays, low tides expose note the absence of exposed algae on the rocks. vast areas of mudflats. The sea may recede several kilometers from the shoreline of high tide Tides Low tide, sandy beach.
    [Show full text]
  • Grade Levels K-1
    Grade Levels K-1 Tlingit Cultural Significance Since time immemorial Tlingit people have survived using what nature provides. Southeast Alaska has a rich, extensive coastline, so Tlingit people gather numerous beach creatures that nourish them. They in turn respect the creatures of the tides and beaches that sustain them. During winter and early spring, when fresh foods weren’t always A series of elementary level thematic units available, they began the tradition of gathering food from the beaches. featuring Tlingit language, culture and history This unit is best suited for the spring because many schools conduct Sea Week/ were developed in Juneau, Alaska in 2004-6. Month activities during April or May. The project was funded by two grants from the U.S. Department of Education, awarded Elder/Culture Bearer Role to the Sealaska Heritage Institute (Boosting Academic Achievement: Tlingit Language Elders/Culture bearers enrich this unit through their knowledge of beach creatures Immersion Program, grant #92-0081844) and gathering and processing techniques. In addition they can help teach the and the Juneau School District (Building on Lingít names of beach creatures and enrich the activities with personalized cultural Excellence, grant #S356AD30001). and historical knowledge. Lessons and units were written by a team of teachers and specialists led by Nancy Overview Douglas, Elementary Cultural Curriculum Lesson #1—Old Woman of the Tides. This Tlingit legend provides a cultural Coordinator, Juneau School District. The context for learning about inter-tidal sea life. Students listen to the legend, team included Juneau teachers Kitty Eddy, sequence events from the story and retell it to others.
    [Show full text]
  • XIV. Appendices
    Appendix 1, Page 1 XIV. Appendices Appendix 1. Vertebrate Species of Alaska1 * Threatened/Endangered Fishes Scientific Name Common Name Eptatretus deani black hagfish Lampetra tridentata Pacific lamprey Lampetra camtschatica Arctic lamprey Lampetra alaskense Alaskan brook lamprey Lampetra ayresii river lamprey Lampetra richardsoni western brook lamprey Hydrolagus colliei spotted ratfish Prionace glauca blue shark Apristurus brunneus brown cat shark Lamna ditropis salmon shark Carcharodon carcharias white shark Cetorhinus maximus basking shark Hexanchus griseus bluntnose sixgill shark Somniosus pacificus Pacific sleeper shark Squalus acanthias spiny dogfish Raja binoculata big skate Raja rhina longnose skate Bathyraja parmifera Alaska skate Bathyraja aleutica Aleutian skate Bathyraja interrupta sandpaper skate Bathyraja lindbergi Commander skate Bathyraja abyssicola deepsea skate Bathyraja maculata whiteblotched skate Bathyraja minispinosa whitebrow skate Bathyraja trachura roughtail skate Bathyraja taranetzi mud skate Bathyraja violacea Okhotsk skate Acipenser medirostris green sturgeon Acipenser transmontanus white sturgeon Polyacanthonotus challengeri longnose tapirfish Synaphobranchus affinis slope cutthroat eel Histiobranchus bathybius deepwater cutthroat eel Avocettina infans blackline snipe eel Nemichthys scolopaceus slender snipe eel Alosa sapidissima American shad Clupea pallasii Pacific herring 1 This appendix lists the vertebrate species of Alaska, but it does not include subspecies, even though some of those are featured in the CWCS.
    [Show full text]
  • Fish Bulletin 161. California Marine Fish Landings for 1972 and Designated Common Names of Certain Marine Organisms of California
    UC San Diego Fish Bulletin Title Fish Bulletin 161. California Marine Fish Landings For 1972 and Designated Common Names of Certain Marine Organisms of California Permalink https://escholarship.org/uc/item/93g734v0 Authors Pinkas, Leo Gates, Doyle E Frey, Herbert W Publication Date 1974 eScholarship.org Powered by the California Digital Library University of California STATE OF CALIFORNIA THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF FISH AND GAME FISH BULLETIN 161 California Marine Fish Landings For 1972 and Designated Common Names of Certain Marine Organisms of California By Leo Pinkas Marine Resources Region and By Doyle E. Gates and Herbert W. Frey > Marine Resources Region 1974 1 Figure 1. Geographical areas used to summarize California Fisheries statistics. 2 3 1. CALIFORNIA MARINE FISH LANDINGS FOR 1972 LEO PINKAS Marine Resources Region 1.1. INTRODUCTION The protection, propagation, and wise utilization of California's living marine resources (established as common property by statute, Section 1600, Fish and Game Code) is dependent upon the welding of biological, environment- al, economic, and sociological factors. Fundamental to each of these factors, as well as the entire management pro- cess, are harvest records. The California Department of Fish and Game began gathering commercial fisheries land- ing data in 1916. Commercial fish catches were first published in 1929 for the years 1926 and 1927. This report, the 32nd in the landing series, is for the calendar year 1972. It summarizes commercial fishing activities in marine as well as fresh waters and includes the catches of the sportfishing partyboat fleet. Preliminary landing data are published annually in the circular series which also enumerates certain fishery products produced from the catch.
    [Show full text]
  • Investigating the Ecological Consequences of Sea Otter Recovery in the Central Coast of British Columbia
    Investigating the Ecological Consequences of Sea Otter Recovery in the Central Coast of British Columbia Part I. Sea Otters, Kelp Forests & Recovery of Northern Abalone Part II. Do Sea Otters Trigger Trophic Cascades in the Rocky Intertidal? Summary Field Report of a 10-day pilot study conducted May 22-31, 2010 Principal Investigators: Lynn Lee & Dr. Anne Salomon Coastal Marine Ecology and Conservation Lab School of Resource and Environmental Management (REM) Hakai Network for Coastal People, Ecosystems and Management Simon Fraser University (SFU) Co-Investigators: Brooke Davis, SFU Environmental Sciences Undergraduate Student Dr. Jane Watson, Vancouver Island University Matt Drake, SFU Biology Undergraduate Student Julie Carpenter, Heiltsuk Integrated Resource Management Department (HIRMD) Stewart Humchitt, Heiltsuk community Submitted to: Frank Brown & Ross Wilson, Heiltsuk Integrated Resource Management Department Steven Hodgson, BC Parks and Protected Areas Eric Peterson & Christina Munck, Tula Foundation Report dated: March 2011 ACKNOWLEDGEMENTS Special thanks to Leandre Vigneault, Taimen Lee Vigneault, Jane Watson, Stan Hutchings and Karen Hansen for volunteering their time and enthusiasm to the field research; to Stewart Humchitt and Julie Carpenter for sharing their knowledge of Heiltsuk territory and lively discussions; to Rod Wargo for competent navigation throughout the Central Coast archipelago; to the staff of Hakai Beach Institute for keeping us well-fed and welcomed; and to Mark Wunsch for photos and video footage. to the Heiltsuk Integrated Resource Management Department for collaborating in this pilot study, including permission to conduct research in Heiltsuk traditional territory. FINANCIAL SUPPORT This project was supported by the Tula Foundation and the Hakai Beach Institute. Financial support was also provided by Anne Salomon’s Coastal Marine Ecology & Conservation (CMEC) Lab through Natural Science and Engineering Research Council of Canada (NSERC) grants.
    [Show full text]
  • GUMBOOT CHITON Cryptochiton Stelleri Middendorff, 1846 (Acanthochitonidae)
    GUMBOOT CHITON Cryptochiton stelleri Middendorff, 1846 (Acanthochitonidae) Global rank G5 (26Jun2006) State rank S5 (26Jun2006) State rank reasons Overall population and trends unknown, but the species is considered locally abundant and widespread in coastal areas. Threatened by human harvest; low recruitment rates make the species vulnerable to overharvest. There is also concern about contamination as a result of individuals are rarely observed (MacGinitie and coastal development and oil spills and the MacGinitie 1968). potential effects of climatic warming. Ecology TaxonomyRecent work by Okusu et al. (2003) Very few predators; they include the lurid places the genus Cryptochiton in a subclade rocksnail (Ocinebrina lurida), tidepool sculpin within the Acanthochitonina along with Tonicella, (Oligocottus maculosus), river otter (Lontra Mopalia, and Katharina, based on genetic and canadensis; O’Clair and O’Clair 1998) and the morphological similarities. large asteroid (Pycnopodia helianthoides; Yates 1989). A traditional source of food for humans, General description but the meat is very tough (Harbo 1997, O’Clair The largest chiton in the world, up to 33 cm long. and O’Clair 1998). The purple urchin In Southeast Alaska, typically smaller, about 15 (Strongylocentrotus purpuratus) and red urchin cm (Yates 1989, O’Clair and O’Clair 1998). (S. franciscanus) may compete with the gumboot Species is unique among chitons because all chiton for space and food (Yates 1989). May be eight plates are completely concealed by the an indirect commensal to coralline algae by thick and leathery reddish brown or brown mantle eating the fleshy red algae that grows on its (Field and Field 1999, Cowles 2005). The surface and reducing the negative effects of underside is yellow or orange, with a broad foot algae overgrowth (Yates 1989).
    [Show full text]
  • Book Club Kit
    BOOK CLUB KIT LINDSAYHATTON.COM LINDSAY_HATTON /HATTTONLINDSAY Hello readers, I’m so happy you’ve chosen Monterey Bay for your book club. Monterey, California is a special place for many people. Its coastline is among the most famous in the world. Its aquarium welcomes nearly two million visitors every year. It has served as a muse for countless writers, artists, philosophers, and scientists, some of whom are characters in my book. I called Monterey home for the first twenty-one years of my life. During high school and college, I worked summers at the Monterey Bay Aquarium. I became well versed in the region’s colorful history and in the natural history of the bay. But to me, there was always something about my hometown that history alone couldn’t quite explain. There seemed to be an imagined tale of heartbreak and ambition just below the factual surface: an alternate founding legend that captured how it felt to stand knee-deep in a tank full of hungry bat rays, to watch the morning fog roll in, to be alone on Cannery Row at midnight and hear the whispers of ghosts. I like to think of Margot Fiske, the protagonist in Monterey Bay, as one of these ghosts. Unlike John Steinbeck and Ed Ricketts, she never actually existed. She is an invented composite of girls and women I’ve read about and known, and of girls and women I could have been. Through her, there are many questions I hope to explore. What is the price of inappropriate desire and its expression? Is it possible to both escape and embrace a family legacy? Do people belong to places, or do places belong to people? Is a true story the same as a story that tells the truth? When, if ever, is captivity preferable to freedom? For those of you who have spent time in Monterey, I hope the book recalls your best memories of this enigmatic and beloved town.
    [Show full text]
  • Applications for British Columbia, Canada, T
    T Applications for British Columbia, Canada, %FDFNCFS +FOO.#VSU]1IJMMJQ"LJOT]&SJO-BUIBN .BSUJOB#FDL]"OOF,4BMPNPO]/BUBMJF$#BO MARINE PROTECTED AREA NETWORK DESIGN FEATURES THAT SUPPORT RESILIENT HUMAN-OCEAN SYSTEMS - APPLICATIONS FOR BRITISH COLUMBIA, CANADA - Authors Jenn M. Burt1,3*, Phillip Akins2, Erin Latham2, Martina Beck2, Anne K. Salomon1,3, Natalie C. Ban2 1 - School of Resource & Environmental Management, Simon Fraser University, Burnaby, B.C., Canada 2 - School of Environmental Studies, University of Victoria, Victoria, B.C., Canada 3 - Hakai Institute, Tula Foundation, Quadra Island, B.C., Canada * Corresponding author - [email protected] Report section lead authors: (1) JMB, (2) JMB, (3) PA, (4) JMB, (5) EL, (6) JMB Citation Burt, J.M., Akins, P., Lathem, E. Beck, M., Salomon, A.K., Ban, N.C. 2014. Marine protected area network design features that support resilient human-ocean systems - Applications for British Columbia, Canada. Simon Fraser University. British Columbia, Canada. 159 pp. Web location http://www.sfu.ca/coastal/research-series/listing/marine-protected-area-network-design-features-that-support--resi.html Disclaimer This frst version of this document was prepared for the Kitasoo/XaiXais First Nation and the Great Bear Initiative Society in July 2013. The contents are the responsibility of the authors and do not necessarily refect the views of the Kitasoo/XaiXais First Nation or the Great Bear Initiative Society. Funding Funding for this report was provided by the Kitasoo/XaiXais First Nation and Coastal First Nations-Great Bear Initiative Society. Additional support for J.M. Burt’s time was provided by NSERC and through the Hakai Institute as a Hakai Scholar.
    [Show full text]
  • Status of Rocky Reef Ecosystems in California 2006 – 2011
    Reef Check Foundation Status of Rocky Reef Ecosystems in California 2006 – 2011 Jan Freiwald, Megan Wehrenberg, Colleen Wisniewski, Gregor Hodgson ISBN number: 978-0-615-82375-1 To cite: Jan Freiwald, Megan Wehrenberg, Colleen Wisniewski, Gregor Hodgson. (2013) Status of Rocky Reef Ecosystems in California 2006 – 2011. Reef Check Foundation, Pacific Palisades, CA, USA. Reef Check Foundation P.O. Box 1057 17575 Pacific Coast Highway Pacific Palisades CA 90272-1057 USA Tel: 1-310-230-2371 Email: [email protected] http://reefcheck.org © 2013 Reef Check Foundation Table of Abbreviations AAUS – American Academy of Underwater Sciences AOP – Aquarium of the Pacific CDFG – California Department of Fish and Game (now called California Department of Fish and Wildlife) CDFW – California Department of Fish and Wildlife CeNCOOS – Central and Northern California Ocean Observing System CIMI – Catalina Island Marine Institute CRANE - Cooperative Research and Assessment of Nearshore Ecosystems EBM – Ecosystem Based Management EML – Ecological Metadata Language HSU – Humboldt State University MBA – Monterey Bay aquarium MLMA – Marine Life Management Act MLPA – Marine Life Protection Act MPA – Marine Protected Area NCCSR – North Central Coast Study Region NED – Nearshore Ecosystem Database NGO – Non-governmental Organization PISCO – Partnership for Interdisciplinary Study of Coastal Oceans QA/QC – Quality Assurance/Quality control RCCA – Reef Check California RLFF – Resource Legacy fund Foundation SCCOOS – Southern California Coastal Ocean Observing System
    [Show full text]
  • UC Riverside UC Riverside Electronic Theses and Dissertations
    UC Riverside UC Riverside Electronic Theses and Dissertations Title High Performance Abrasion-Resistant Materials: Lessons from Nature Permalink https://escholarship.org/uc/item/5z84503s Author Wang, Qianqian Publication Date 2012 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA RIVERSIDE High Performance Abrasion-Resistant Materials: Lessons from Nature A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Chemical and Environmental Engineering by Qianqian Wang September 2012 Dissertation Committee: Dr. David Kisailus, Chairperson Dr. Guanshui Xu Dr. Pablo D. Zavattieri Copyright by Qianqian Wang 2012 The Dissertation of Qianqian Wang is approved: _____________________________________________ _____________________________________________ ____________________________________________ Committee Chairperson University of California, Riverside Acknowledgements I want to thank my advisor, Dr. David Kisailus, for his incredible support and help on this project during the past four years. Passionate, knowledgeable and insightful in materials science, he gave me guidance and inspiration for this project. Kind, nice and patient, Dr. Kisailus made my research life as a Ph. D. student easier. He helped me a lot in conducting experiments, analyzing data and writing paper. Dr. Kisailus also helped me a lot in the skills of presentation and academic communications. With his support, I got the chance to present my work at several world class conferences. I am also grateful for his help in the guidance for my career development. It will never be overestimated about how much Dr. Kisailus helped me during the past four years for Ph.D. study. I want to thank Dr. James Weaver, who was a post-doctoral researcher in our lab and worked on this project before September 2009.
    [Show full text]
  • Layout Molluscs Program Guide
    Branches on the Tree of Life Molluscs Written and Photographed by David Denning and Bruce J. Russell Produced by BioMEDIA ASSOCIATES, ©2006 Running Time 18 minutes The Phylum Mollusca is the second most diverse phylum of living animals, with more than 60,000 known species alive today. Molluscs have also left a remarkable fossil record with over 40,000 described extinct species, some going back over 500 million years to early Cambrian times. This excellent fossil record is largely a result of the hard, calcifi ed shells produced by these extinct mollusc species. One of the earliest Molluscs groups was the Monoplacophora, which had limpet-like shells, but a distinctive body with pairs of gills in along the sides of the mantle cavity. This group is represented by a fossil of Scenella shown in this program which was found in the Burgess Shales of British Columbia. Only a few species of Monoplacophorans, such as the ‘living fossil’ Neopolina, survive today in very deep ocean basins. The word ‘mollusc’ means ‘soft-bodied’. The mollusc body is bilaterally symmetrical. Most Molluscs have a muscular foot, which can take a variety of forms, and is used variously for crawling, digging, or swimming. Most molluscs are protected by a hard shell made from calcium carbonate minerals extracted from the water. The shell is secreted along a rim of soft tissue called the mantle, which forms the mantle cavity hiding a delicate set of gills. While the gills are typically ‘feather-like’ in most species, some molluscs have modifi ed gills and others exchange oxygen and carbon dioxide directly through the skin.
    [Show full text]