DOCSLIB.ORG

Diatom Ooze .,Eanography,P,Ankton

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Diatom Ooze .,Eanography,P,Ankton Bridge Ocean Education Teacher Resource Center Page 1 of 2 ' Bridge DATA Series OCEAN SCIENCE TOPICS Ooze LESSON PLANS Clues Diatom Ooze RESEARCH 8i DATA CONNECTXONS Written by: Lisa Ayers Lawrence, Virginia Sea Grant, Virginia Institute of Marlne Science PRQFkSSLONAL DEVELOPMENT Summary Plot the distribution of various oozes using information from Grade Level: GUIDING STU[)EN'TS sediment maps. 9-12 IPE5QIIHCE CENTER Objectives Lesson Time: ABOUT THE UKJDGE 1 hr. COMMUNICATE Descr~bethe characterlstlcs of d~fferenttypes of seafloor sediments and oozes Materials Required: IiOME Predict dlstrlbut~onof calcareous and s~l~ceousoozes. global map, Sediment Compare and discuss locat~onsof sed~mentsand oozes. DistrlbMion Patterns map Vocabulary Terrlgenous, Blogenous, Hydrogenous, Cosmogenous, Calcareous Natl. Science Standards ooze, Slllceous ooze, Foram~nlfera,Dlatoms, ad~olarla,Carbonate compensat~ondepth --Click here for a listof the aligned National Gence Education Introduction --Standards. 1 Jr\ NATI~~A~svlARI~~ Just as ocean beaches display a variety of sediment types, the ocean Related Resources EDUCATORS ASSOCIATION floor may be made or: sand, rock, remains of living organisms, or Geologgal other material. The grains and particles that make up the seafloor .,eanography,P,ankton, /? sediments are classified by their size and their point of origin. I' I Benthos cx: .\. ! Sediments can come from land (terrigenous), from living organisms \, (biogenous), from chemical reactions in the water column (hydrogenous), and even from outer ,.>A ,&>~(4 , space (cosmogenous). Terriqenous sediments dominate the edqes of the ocean basins, close to land where they originated. As move deeper into the ocean basins, biogenous sediments begin to dominate. ~iogenous sediments can consist of waste products or remains of organisms, including those of microscopic phytoplankton and zooplankton. When skeletal remains of microscopic organisms make up more than 30% of the sediment, it is called "ooze." There are two types of oozes, calcareous ooze and siliceous ooze. Calcareous ooze, the most abundant of all biogenous sediments, comes from organisms whose shells (also called tests) are calcium-based, such as those of foraminifera, a type of zooplankton. Foraminifera are one of the most abundant types of zooplankton and are widely distributed throughout the surface of the world's oceans. Siliceous oozes are made up of the remains of di~atornn,a microscopic phytoplankton, and radiolaria, a microscopic zooplankton. Diatoms are one of the most important primary producers in the ocean. Because they are primary producers, diatoms are found in nutrient-rich areas of the ocean especially in areas of upwelling like the polar seas. As you move from continental shelf to open ocean areas, the number of diatoms present decreases. Radiolarians, the other source of siliceous ooze, feed on phytoplankton and thus are also more abundant in nutrient-rich water. However, radiolaria favor the equatorial upwelling zones as opposed to the polar upwelling zones. Another factor that affects where biogenous sediments will occur is the depth of the ocean floor. Calcium carbonate dissolves readily under pressure and in cold water, therefore deeper ocean floors will have less calcareous ooze. At a depth of about 5 km, the rate of dissolution (how quickly calcium carbonate dissolves) is faster than the rate at which caicium shells are raining down from above. This depth is called the carbonate compensation depth or CCD. Data Activity Bridge Ocean Education Teacher Resource Center Page 2 of 2 DATA ACTIVITY Using what you've learned about the distribution of diatoms, radiolaria and foraminifera and about the carbonate compensation depth, predict where you think you would find calcareous and siliceous oozes. Print a globl-map, and mark your predictions on it. Next, print the General Sediment Distribution patterns map. This map shows the general location of biogenous sediments. Compare your map to the sediment distribution map. QUESTIONS Were your predictions close to where calcareous and siliceous oozes actually occur? How does your map compare with the seqiment distribution map? Which type of ooze dominates the ocean sediments, calcareous or siliceous? Why? What parts of the oceans do not have calcareous ooze? What might be some reasons for this? (Hint: depth, distribution of organisms) Where are large deposits of siliceous diatom ooze? Are these deposits mostly near the edges of continents or in the middle of the ocean basins? Why? (Hint: areas of upwelling/high nutrient levels) Where do you see large deposits of siliceous radiolarian ooze? Why? The Bridge is S~O~PSQP~~by NOAA Sea Grant and the National Marine-Educata_rs Association @ Virginiil Sca Grn~ilMdtine Advisory Program Virginia Institute of Marine Science College of William and Mary Introduction to the Foraminifera Page 1 of 2 Introduction to the Foraminifera Foraminifera (forams for short) are single-celled protiss with shells. Their shells are also referred to as tests because in some forms the protoplasm covers the exterior of the shell. The shells are commonly divided into chambers which are added during growth, though the simplest forms are open tubes or hollow spheres. Depending on the species, the shell may be made of organic compounds, sand grains and other particles cemented together, or crystalline calcite. A typical foram : In the picture about, the dark brown structure is the test, or shell, inside which the foram lives. Radiating from the opening are fine hairlike reticulopodia, which the foram uses to find and capture food. Fully grown individuals range in size from about 100 micrometers to almost 20 centimeters long. A single individual may have one or many nuclei within its cell. The largest living species have a symbiotic relationship with algae, which they "farm" inside their shells. Other species eat foods ranging from dissolved organic molecules, bacteria, diatoms and other single celled phytoplankton, to small animals such as copepods. They move and catch their food with a network of thin extensions of the cytoplasm called reticulopodia, similar to the pseudopodia of an amoeba, although much more numerous and thinner. Click on the buttons below to learn more about Foraminifera. Introduction to the Foraminifera Page 2 of 2 Por more information about foraminifera : Try the Gulf of St.t.Law_r_ece Database, including images and information on Late Quaternary micro fossils. Clickhere to see images of some type specimens from the UCMP inicrofossil -collect~ns. - UCMP shartcuts: tree time I home of life : periods : to(3ics glossary ; help Introduction to the Bacillariophyta Page 1 of 2 Introduction to Bacillariophyta (The Diatoms) Life inside a glass box. The Bacillariophyta are the diatoms. With their exquisitely beautihl silica shells, or frustules such as that of Odontella shown above at right, diatoms are among the loveliest microfossils. They are also among the most important aquatic microorganisms today: they are extremely abundant both in the plankton and in sediments in marine and freshwater ecosystems, and because they are photosynthetic they are an important food source for marine organisms. Some may even be found in soils or on moist mosses. Diatoms have an extensive fossil record going back to the Cretaceous; some rocks are forrned almost entirely of fossil diatoms, and are known as diatomite or diatomaceous earth. These deposits are mined conlmercially as abrasives and filtering aids. Analysis of fossil diatom assemblages may also provide important inforrnation on past environmental conditions. Click on the buttons below to learn more about the Diatoms. Introduction to the Bacillariophyta Page 2 of 2 You can search the UCMP ii~icropaleontology~type collection for diatoms. For more information on diatoms and how they are used in environmental reconstruction, check out the Paleolimnology and Diatom Home Pages maintained by P. Roger Sweets at Indiana University, or visit the Aka1 Microscopy and Image Digitization~HoinePage at Bowling Green State University for many images of diatoms. You might also want to visit the Diato.m_Collectioils_of the California Academy of Sciences, including databases on diatom genera and literature. A general article 011 diatoms (15 Sep 1997) is available from the Mining Company. UCMP shortcuts: tree time topics gSossary j help : home ' of life periods ' ' Image of living diatom courtesy Virtual Foliage at the University of Wisconsin. Electron micrograph of Odontella taken by Karen Wetmore at UCMP. - - - Molecular Expressions Photo Gallery: Radiolarians Page 1 of 4 Radiolarians Mixed Radiolarians in Darkfield Illumination Radiolarians Radiolarians are single-celled protistan marine organisms that distinguish themselves with their unique and intricately detailed glass-like exoskeletons. During their life cycle, radiolarians absorb silicon compounds from their aquatic environment and secrete well-defined geometric networks that comprise a skeleton commonly known as a test. The radiolarian tests are produced in a wide variety of patterns, but most consist of an organized array of spines and holes (pores) that regulate a network of pseudopods useful in gathering food. When observed with an optical microscope, radiolarian tests are found to be low contrast light-scattering objects that are best viewed using Rheinberg illumination, darkfield illumination, phase contrast, or differential interference contrast (DIC) microscopy techniques. The diversity and beauty of radiolarian
Load more

Recommended publications
  • Molecular Phylogenetic Position of Hexacontium Pachydermum Jørgensen (Radiolaria)
    Marine Micropaleontology 73 (2009) 129–134 Contents lists available at ScienceDirect Marine Micropaleontology journal homepage: www.elsevier.com/locate/marmicro Molecular phylogenetic position of Hexacontium pachydermum Jørgensen (Radiolaria) Tomoko Yuasa a,⁎, Jane K. Dolven b, Kjell R. Bjørklund b, Shigeki Mayama c, Osamu Takahashi a a Department of Astronomy and Earth Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan b Natural History Museum, University of Oslo, P.O. Box 1172, Blindern, 0318 Oslo, Norway c Department of Biology, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan article info abstract Article history: The taxonomic affiliation of Hexacontium pachydermum Jørgensen, specifically whether it belongs to the Received 9 April 2009 order Spumellarida or the order Entactinarida, is a subject of ongoing debate. In this study, we sequenced the Received in revised form 3 August 2009 18S rRNA gene of H. pachydermum and of three spherical spumellarians of Cladococcus viminalis Haeckel, Accepted 7 August 2009 Arachnosphaera myriacantha Haeckel, and Astrosphaera hexagonalis Haeckel. Our molecular phylogenetic analysis revealed that the spumellarian species of C. viminalis, A. myriacantha, and A. hexagonalis form a Keywords: monophyletic group. Moreover, this clade occupies a sister position to the clade comprising the spongodiscid Radiolaria fi Entactinarida spumellarians, coccodiscid spumellarians, and H. pachydermum. This nding is contrary to the results of Spumellarida morphological studies based on internal spicular morphology, placing H. pachydermum in the order Nassellarida Entactinarida, which had been considered to have a common ancestor shared with the nassellarians. 18S rRNA gene © 2009 Elsevier B.V. All rights reserved. Molecular phylogeny. 1. Introduction the order Entactinarida has an inner spicular system homologenous with that of the order Nassellarida.
    [Show full text]
  • Sediment Activity Answer Key
    Sediment Activity Answer Key 1. Were your predictions close to where calcareous and siliceous oozes actually occur? Answers vary. 2. How does your map compare with the sediment distribution map? Answers vary. 3. Which type of ooze dominates the ocean sediments, calcareous or siliceous? Why? Calcareous sediments are formed from the remains of organisms like plankton with calcium-based skeletons1, such as foraminifera, while siliceous ooze is formed from the remains of organisms with silica-based skeletons like diatoms or radiolarians. Calcareous ooze dominates ocean sediments. Organisms with calcium-based shells such as foraminifera are abundant and widely distributed throughout the world’s ocean basins –more so than silica-based organisms. Silica-based phytoplankton such as diatoms are more limited in distribution by their (higher) nutrient requirements and temperature ranges. 4. What parts of the ocean do not have calcareous ooze? What might be some reasons for this? Remember that ooze forms when remains of organisms compose more than 30% of the sediment. The edges of ocean basins bordering land tend to have a greater abundance of lithogenous sediment –sediment that is brought into the ocean by water and wind. The proportion of lithogenous sediment decreases however as you move away from the continental shelf. In nutrient rich areas such as upwelling zones in the polar and equatorial regions, silica-based organisms such as diatoms or radiolarians will dominate, making the sediments more likely to be a siliceous-based ooze. Further, factors such as depth, temperature, and pressure can affect the ability of calcium carbonate to dissolve. Areas of the ocean that lie beneath the carbonate compensation depth (CCD), below which calcium carbonate dissolves, typically beneath 4-5 km, will be dominated by siliceous ooze because calcium-carbonate-based material would dissolve in these regions.
    [Show full text]
  • Rhizaria, Cercozoa)
    Protist, Vol. 166, 363–373, July 2015 http://www.elsevier.de/protis Published online date 28 May 2015 ORIGINAL PAPER Molecular Phylogeny of the Widely Distributed Marine Protists, Phaeodaria (Rhizaria, Cercozoa) a,1 a a b Yasuhide Nakamura , Ichiro Imai , Atsushi Yamaguchi , Akihiro Tuji , c d Fabrice Not , and Noritoshi Suzuki a Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041–8611, Japan b Department of Botany, National Museum of Nature and Science, Tsukuba 305–0005, Japan c CNRS, UMR 7144 & Université Pierre et Marie Curie, Station Biologique de Roscoff, Equipe EPPO - Evolution du Plancton et PaléoOcéans, Place Georges Teissier, 29682 Roscoff, France d Institute of Geology and Paleontology, Graduate School of Science, Tohoku University, Sendai 980–8578, Japan Submitted January 1, 2015; Accepted May 19, 2015 Monitoring Editor: David Moreira Phaeodarians are a group of widely distributed marine cercozoans. These plankton organisms can exhibit a large biomass in the environment and are supposed to play an important role in marine ecosystems and in material cycles in the ocean. Accurate knowledge of phaeodarian classification is thus necessary to better understand marine biology, however, phylogenetic information on Phaeodaria is limited. The present study analyzed 18S rDNA sequences encompassing all existing phaeodarian orders, to clarify their phylogenetic relationships and improve their taxonomic classification. The mono- phyly of Phaeodaria was confirmed and strongly supported by phylogenetic analysis with a larger data set than in previous studies. The phaeodarian clade contained 11 subclades which generally did not correspond to the families and orders of the current classification system. Two families (Challengeri- idae and Aulosphaeridae) and two orders (Phaeogromida and Phaeocalpida) are possibly polyphyletic or paraphyletic, and consequently the classification needs to be revised at both the family and order levels by integrative taxonomy approaches.
    [Show full text]
  • Dive Into Oceanography with Trusted Content and Innovative Media
    Dive into Oceanography with Trusted Content and Innovative Media The best-selling brief book in the oceanography market combines dynamic visuals and a student-friendly narrative to bring oceanography to life and inspire students to engage and learn more about the oceans and environments around them. The 13th edition creates an interactive learning experience, providing tightly integrated text and digital offerings that make oceanography approachable and digestible for students. An emphasis on the process of science throughout the text provides students with an understanding of how scientists think and work. It also helps students develop the scientific skills of devising experiments and interpreting data. A01_TRUJ1521_13_SE_WALK.indd 1 28/11/2018 13:12 Dive into the Process of Science GraphIt! Activities are a great way to help your students develop their understanding of graphs and data. These activities use real data to help students build science literacy skills and their understanding of how to analyze and interpret graphs. 4.5 What Are the Characteristics of Cosmogenous Sediment? 125 PROCESS OF SCIENCE 4.1: extinction, large outpourings of basaltic did not reveal any K–T deposits. Evidently, When The Dinosaurs Died: volcanic rock in India (called the Deccan the impact and resulting huge waves had Traps) and other locations had occurred. stripped the ocean floor of its sediment. The Cretaceous–Tertiary Also, if there was a catastrophic meteor However, at 1600 kilometers (1000 miles) (K–T) Event impact, where was the crater? from the impact site, the telltale sediments In the early 1990s, the 190-kilometer from the catastrophe, such as the iridium- BACKGROUND (120-mile)-wide Chicxulub (pronounced rich clay layer, were preserved in sea floor The extinction of the dinosaurs—and about “SCHICK-sue-lube”) Crater off the Yu- sediments.
    [Show full text]
  • September 2002
    RADI LARIA VOLUME 20 SEPTEMBER 2002 NEWSLETTER OF THE INTERNATIONAL ASSOCIATION OF RADIOLARIAN PALEONTOLOGISTS ISSN: 0297.5270 INTERRAD International Association of Radiolarian Paleontologists A Research Group of the International Paleontological Association Officers of the Association President Past President PETER BAUMBARTNER JOYCE R. BLUEFORD Lausanne, Switzerland California, USA [email protected] [email protected] Secretary Treasurer JONATHAN AITCHISON ELSPETH URQUHART Department of Earth Sciences JOIDES Office University of Hong Kong Department of Geology and Geophysics Pokfulam Road, University of Miami - RSMAS Hong Kong SAR, 4600 Rickenbacker Causeway CHINA Miami FL 33149 Florida Tel: (852) 2859 8047 Fax: (852) 2517 6912 U.S.A. e-mail: [email protected] Tel: 1-305-361-4668 Fax: 1-305-361-4632 Email: [email protected] Working Group Chairmen Paleozoic Cenozoic PATRICIA, WHALEN, U.S.A. ANNIKA SANFILIPPO California, U.S.A. [email protected] [email protected] Mesozoic Recent RIE S. HORI Matsuyama, JAPAN DEMETRIO BOLTOVSKOY Buenos Aires, ARGENTINA [email protected] [email protected] INTERRAD is an international non-profit organization for researchers interested in all aspects of radiolarian taxonomy, palaeobiology, morphology, biostratigraphy, biology, ecology and paleoecology. INTERRAD is a Research Group of the International Paleontological Association (IPA). Since 1978 members of INTERRAD meet every three years to present papers and exchange ideas and materials INTERRAD MEMBERSHIP: The international Association of Radiolarian Paleontologists is open to any one interested on receipt of subscription. The actual fee US $ 15 per year. Membership queries and subscription send to Treasurer. Changes of address can be sent to the Secretary.
    [Show full text]
  • Radiozoa (Acantharia, Phaeodaria and Radiolaria) and Heliozoa
    MICC16 26/09/2005 12:21 PM Page 188 CHAPTER 16 Radiozoa (Acantharia, Phaeodaria and Radiolaria) and Heliozoa Cavalier-Smith (1987) created the phylum Radiozoa to Radiating outwards from the central capsule are the include the marine zooplankton Acantharia, Phaeodaria pseudopodia, either as thread-like filopodia or as and Radiolaria, united by the presence of a central axopodia, which have a central rod of fibres for rigid- capsule. Only the Radiolaria including the siliceous ity. The ectoplasm typically contains a zone of frothy, Polycystina (which includes the orders Spumellaria gelatinous bubbles, collectively termed the calymma and Nassellaria) and the mixed silica–organic matter and a swarm of yellow symbiotic algae called zooxan- Phaeodaria are preserved in the fossil record. The thellae. The calymma in some spumellarian Radiolaria Acantharia have a skeleton of strontium sulphate can be so extensive as to obscure the skeleton. (i.e. celestine SrSO4). The radiolarians range from the A mineralized skeleton is usually present within the Cambrian and have a virtually global, geographical cell and comprises, in the simplest forms, either radial distribution and a depth range from the photic zone or tangential elements, or both. The radial elements down to the abyssal plains. Radiolarians are most useful consist of loose spicules, external spines or internal for biostratigraphy of Mesozoic and Cenozoic deep sea bars. They may be hollow or solid and serve mainly to sediments and as palaeo-oceanographical indicators. support the axopodia. The tangential elements, where Heliozoa are free-floating protists with roughly present, generally form a porous lattice shell of very spherical shells and thread-like pseudopodia that variable morphology, such as spheres, spindles and extend radially over a delicate silica endoskeleton.
    [Show full text]
  • (Rhizaria) to Biogenic Silica Export in the California Current Ecosystem
    Global Biogeochemical Cycles RESEARCH ARTICLE The Significance of Giant Phaeodarians (Rhizaria) 10.1029/2018GB005877 to Biogenic Silica Export in the California Key Points: Current Ecosystem • Phaeodarian skeletons contain large amounts of silica (0.37–43.42 μg Si/ Tristan Biard1 , Jeffrey W. Krause2,3 , Michael R. Stukel4 , and Mark D. Ohman1 cell) that can be predicted from cell size and biovolume 1Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA, 2Dauphin Island Sea Lab, • Phaeodarian contribution to bSiO2 3 4 export from the euphotic zone Dauphin Island, AL, USA, Department of Marine Sciences, University of South Alabama, Mobile, AL, USA, Earth, Ocean, and increases substantially toward Atmospheric Science Department, Florida State University, Tallahassee, FL, USA oligotrophic regions with low total bSiO2 export • Worldwide, Aulosphaeridae alone Abstract In marine ecosystems, many planktonic organisms precipitate biogenic silica (bSiO2) to build fi may represent a signi cant proportion silicified skeletons. Among them, giant siliceous rhizarians (>500 μm), including Radiolaria and Phaeodaria, of bSiO2 export to the deep mesopelagic ocean (>500 m) are important contributors to oceanic carbon pools but little is known about their contribution to the marine silica cycle. We report the first analyses of giant phaeodarians to bSiO2 export in the California Current μ Supporting Information: Ecosystem. We measured the silica content of single rhizarian cells ranging in size from 470 to 3,920 m • Supporting Information S1 and developed allometric equations to predict silica content (0.37–43.42 μg Si/cell) from morphometric • Figure S1 measurements. Using sediment traps to measure phaeodarian fluxes from the euphotic zone on four cruises, • Figure S2 • Figure S3 we calculated bSiO2 export produced by two families, the Aulosphaeridae and Castanellidae.
    [Show full text]
  • 4. a Growth Model for Polymetallic Nodules
    A GEOLOGICAL MODEL OF POLYMETALLIC NODULE DEPOSITS IN THE CLARION‐CLIPPERTON FRACTURE ZONE ISA TECHNICAL STUDY SERIES Technical Study No. 1 Global Non‐Living Resources on the Extended Continental Shelf: Prospects at the year 2000 Technical Study No. 2 Polymetallic Massive Sulphides and Cobalt‐Rich Ferromanganese Crusts: Status and Prospects Technical Study No. 3 Biodiversity, Species Ranges and Gene Flow in the Abyssal Pacific Nodule Province: Predicting and Managing the Impacts of Deep Seabed Mining Technical Study No. 4 Issues associated with the Implementation of Article 82 of the United Nations Convention on the Law of the Sea Technical Study No. 5 Non‐Living resources of the Continental Shelf beyond 200 nautical miles: Speculations on the Implementation of Article 82 of the United Nations Convention on the Law of the Sea PAGE | II A GEOLOGICAL MODEL OF POLYMETALLIC NODULE DEPOSITS IN THE CLARION‐ CLIPPERTON FRACTURE ZONE This report contains a summary of two documents – A Geological Model of Polymetallic Nodule Deposits in the Clarion‐Clipperton Fracture Zone and a Prospector’s Guide prepared under the project ‘Development of a Geological Model of Polymetallic Nodule Deposits in the Clarion‐Clipperton Fracture Zone, Pacific Ocean’. ISA TECHNICAL STUDY: NO. 6 International Seabed Authority Kingston, Jamaica PAGE | III The designation employed and the presentation of materials in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the International Seabed Authority concerning the legal status of any country or territory or of its authorities, or concerning the delimitation of its frontiers or maritime boundaries. All rights reserved.
    [Show full text]
  • Phylogenomics Supports the Monophyly of the Cercozoa T ⁎ Nicholas A.T
    Molecular Phylogenetics and Evolution 130 (2019) 416–423 Contents lists available at ScienceDirect Molecular Phylogenetics and Evolution journal homepage: www.elsevier.com/locate/ympev Phylogenomics supports the monophyly of the Cercozoa T ⁎ Nicholas A.T. Irwina, , Denis V. Tikhonenkova,b, Elisabeth Hehenbergera,1, Alexander P. Mylnikovb, Fabien Burkia,2, Patrick J. Keelinga a Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada b Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok 152742, Russia ARTICLE INFO ABSTRACT Keywords: The phylum Cercozoa consists of a diverse assemblage of amoeboid and flagellated protists that forms a major Cercozoa component of the supergroup, Rhizaria. However, despite its size and ubiquity, the phylogeny of the Cercozoa Rhizaria remains unclear as morphological variability between cercozoan species and ambiguity in molecular analyses, Phylogeny including phylogenomic approaches, have produced ambiguous results and raised doubts about the monophyly Phylogenomics of the group. Here we sought to resolve these ambiguities using a 161-gene phylogenetic dataset with data from Single-cell transcriptomics newly available genomes and deeply sequenced transcriptomes, including three new transcriptomes from Aurigamonas solis, Abollifer prolabens, and a novel species, Lapot gusevi n. gen. n. sp. Our phylogenomic analysis strongly supported a monophyletic Cercozoa, and approximately-unbiased tests rejected the paraphyletic topologies observed in previous studies. The transcriptome of L. gusevi represents the first transcriptomic data from the large and recently characterized Aquavolonidae-Treumulida-'Novel Clade 12′ group, and phyloge- nomics supported its position as sister to the cercozoan subphylum, Endomyxa. These results provide insights into the phylogeny of the Cercozoa and the Rhizaria as a whole.
    [Show full text]
  • 20. Shell Horizons in Cenozoic Upwelling-Facies Sediments Off Peru: Distribution and Mollusk Fauna in Cores from Leg 1121
    Suess, E., von Huene, R., et al., 1990 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 112 20. SHELL HORIZONS IN CENOZOIC UPWELLING-FACIES SEDIMENTS OFF PERU: DISTRIBUTION AND MOLLUSK FAUNA IN CORES FROM LEG 1121 Ralph Schneider2 and Gerold Wefer2 ABSTRACT Shell layers in cores extracted from the continental margin off Peru during Leg 112 of the Ocean Drilling Program (ODP) show the spatial and temporal distribution of mollusks. In addition, the faunal composition of the mollusks in these layers was investigated. Individual shell layers have been combined to form shell horizons whose origin has been traced to periods of increased molluscan growth. It seems that the limiting factor for the growth of mollusks in upwelling regions near the coast of Peru is primarily the oxygen content of the bottom water. Optimal living conditions for mollusks are found at the upper boundary of the oxygen-minimum layer (OML). This OML in the modern sea ranges in depths from 100 to 500 m. Fluctuations in the OML boundary control the spatial and temporal distribution of shell horizons on the outer shelf and upper continental slope. The distribution of mollusks depends further on tectonic events and bottom current effects in the study area. In the range of outer shelf and upper slope, these shell horizons were developed during times of lowered sea level, from the late Miocene through the Quaternary, especially during glacial episodes in the late Quaternary. INTRODUCTION comprehensive reviews of the bivalve and gastropod taxon• omy of the equatorial East Pacific faunal province, but con• Ten holes were drilled using the drill ship JOIDES Reso• tained little information about the ecology of the genera lution during Leg 112, in November and December 1986, on described.
    [Show full text]
  • Ocean Deposits Ocean Deposits Are the Unconsolidated Sediments (Inorganic Or Organic ) Derived from Various Sources Deposited on the Oceanic Floor
    Ocean Deposits Ocean deposits are the unconsolidated sediments (Inorganic or Organic ) derived from various sources deposited on the oceanic floor. What are the sources of these ocean deposits ? These ocean deposits are derived from three major sources: 1- Terrigenous Sources 2- Volcanic Deposits 3- Pelagic Deposits What are Terrigenous Deposits ? Weathering is an ongoing process being carried upon,on the various continental rocks by numerous mechanical and chemical agents. As a result of which, these rocks get disintegrated and get decomposed to form fine to coarse sediments.These sediments brought by rivers, streams, winds, glaciers, oceanic currents, waves etc get deposited upon the continental margins are thereby known as terrigenous deposits. The shape and size of these materials differ which in turn influence their seaward distribution. Bigger sized sediments get deposited near the coast such as boulders, cobbles and pebbles, while the finer sediments get deposited away from the sea coast. On the basis of size of particles and density, following pattern has been identified. Deposit Size( Diameter) Gravel 2mm- 256mm Sand 1mm – 1/16mm Silt 1/32mm – 1/256mm Clay 1/256mm – 1/8192mm Mud Finer than 1/8192mm Mud has been further classified into following categories: Type of Mud Characteristics Sediments derived from rocks containing Iron Blue Mud Sulphide and decomposed organic content. Sediments derived from rocks containing Iron Red Mud Oxide Color of blue mud changes into green due to reaction with sea water. It Contains silicates of Green Mud potassium and glauconites Derived from coral reefs located on continental Coral Mud shelf What are Volcanic Deposits ? These are the materials which are deposited in marine environment by volcanic eruptions on land which are carried by wind, river, rain wash etc to the oceans and volcanic eruption in the ocean which deposit sediments directly into the ocean.
    [Show full text]
  • Pyritized Radiolarians from the Mid-Cretaceous Deposits of the Pieniny Klippen Belt — a Model of Pyritization in an Anoxic Environment
    GEOLOGICA CARPATHICA, 51, 2, BRATISLAVA, APRIL 2000 9 1 -9 9 PYRITIZED RADIOLARIANS FROM THE MID-CRETACEOUS DEPOSITS OF THE PIENINY KLIPPEN BELT — A MODEL OF PYRITIZATION IN AN ANOXIC ENVIRONMENT MARTA BĄK and ZBIGNIEW SAWŁOWICZ Institute of Geological Sciences, Jagiellonian University, Oleandry 2A, 30-063 Kraków, Poland; [email protected] (Manuscript received August 24, 1999; accepted in revised form March 15, 2000) Abstract: Excellently preserved, pyritized radiolarian skeletons have been found within the Upper Cenomanian de­ posits in the Pieniny Klippen Belt (PKB—Carpathians, Poland). On the basis of a study of their chemical composi­ tion, structure of replacing skeletons and exceptional preservation of all morphological details, we propose a new model where the pyritization process took place not in sediment but while the radiolarian skeletons were suspended in the anoxic water column. The radiolarians rich in organic matter, sinking through the upper (iron-rich) part of an anoxic water column, became the sites of organic matter decomposition and enhanced bacterial sulphate reduction. Dissolved iron in this zone diffused into the radiolarians and precipitated as iron sulphides replacing the opaline skeletons. This process was controlled by the rates of opal dissolution and of bacterial sulphate reduction, and the availability of dissolved iron. The preservation of radiolarians in the Upper Cenomanian deposits from different depth sub-basins of the PKB was compared. We found that the extent of pyritization and preservation of radiolarian skel­ etons may be dependent on the depth of the basin and the position of the oxic-anoxic interface. Key words: Carpathians, Pieniny Klippen Belt, anoxic event, pyritization, Radiolaria.
    [Show full text]