Protozoa in the Deep Sea Foraminifera Xenophyophores Gromids WHY THEIR OWN LECTURE among the most abundant organisms relatively little known about modern forms key intermediaries in elemental cycling important proxies for paleo studies very beautiful cool and interesting Studies of agglutinated protozoans have lagged behind others because the tests are so fragile early sampling methods did not recover organisms intact sorters failed to pay attention to small mud lumps 1 Deep Sea Trends 1 Increased representation of protozoa with depth foraminiferans xenophyophores become abundant forams 50 of deep sea meiofauna 2 Dwarfish and gigantism increase with depth Agglutinating calcareous forams contribute to dwarfism Xenophyophores some agglut forams are giants 3 High species diversity Biogenic structures of agglutinating protozoans may contribute to diversity maintenance among metazoans Foraminifera Domain Eukaryota Kingdom Animalia Grade Protozoa Protocista Phylum Sarcomastigophora Subphylum Sarcodina Superclass Rhizopoda Class Foraminifera 2 Foraminifera ameboid protists testate Granuloreticulosea have a test anastomosing granular pseudopodia interact with environment through pseudopods motility attachment feeding building tests protection respiration reproduction date back to early Cambrian only group to range from nanobenthos to megabenthos 10 mm to 10 cm 900 genera 10 000 species Two Groups Monothalamous unilocular single chambered primitive Polythalamous multilocular multichambered 3 Types of Foraminifera Calcareous forms calcite tests secreted by foraminifera single or multichambered many shapes Bulimina aculeata H elegans Globobulimina pyrula Chilostomella ovoidea Globobulimina auricula Agglutinated Multichambered Discospira 4 What is an agglutinated foraminiferan Conqueria laevis 5 m Agglutinated forms tests formed of mineral grains or other tests Foraminifer generates glue to hold particles Textularids multichambered species common Komokiacians 1 5 mm branching tubules central ocean below CCD Microforaminifera Nanoforaminifera all types 5 Examples of monothalamous foraminifera with agglutinated walls saccamminids species with one aperture All from the deep NE Atlantic Sausage shaped saccamminids with dull surfaces 400m 712m 400m 712m 700m 700m 6 Allogromids tectinous organic tests soft shelled Major constituent of sediments but often ignored e g 41 of meiobenthos in Aleutian Trench Related to unilocular foraminifera single chambered Present in freshwater terrestrial and marine settings Examples of monothalamous foraminifera with organic walls allogromiids species with one aperture Weddell Sea Central Pacific NE Atlantic 7 Examples of monothalamous foraminifera with organic walls allogromiids species with two apertures NE Atlantic NE Atlantic North Pacific Off Spitzbergen NE Atlantic are less than 1 protoplasm by volume 8 Gromids testate ameboe order Filosea non anastomosing pseudopods organic test Gromia sphaerica Phylum Cercozoa Genus Gromia testate amoebae with filose pseudopodia Phylum Foraminifera testate amoebae with granuloreticulate pseudopodia Photos Sam Bowser Gromia oviformis 9 Giant gromiids from the Arabian Sea Gromia sphaerica 1640 m water depth Specimen in box core Pakistan Margin 1700 m Gromia sphaerica on the Pakistan margin1850 m Cluster of specimens Molecular evidence suggests that Gromia is closely related to Foraminifera Neighbor joining tree of eukaryotes based on SSU rDNA sequences Jan Pawlowski 10 Gromiids may have been ancestoral to the foraminifera during the Neoproterozic Pawlowski et al 2003 Proceedings of the National Academy of Sciences Phylogenetic relationships among 79 unilocular and 21 multilocular foraminifera inferred from partial SSU rDNA gene sequences Pawlowski Holzmann Berney Fahrni Gooday Cedhagen Habura Bowser 2003 The evolution of early foraminifera Proceedings of the National Academy of Sciences 11 Foraminiferan Size Structure most forams are 150 m Gooday et al 1995 North Atlantic Black allogromids dotted Laegenammiina diagonal hatching tubular agglut white other Composition Abyssal NE Atlantic 4850 m 12 Calcareous species dominate shelf and bathyal settings below the CCD agglutinated forms dominate Douglas Woodruff 1981 13 Foraminifera Metazoan macrofaunal communities behave similarly 300 microns NC Slope 850 m Gooday et al 2001 Site I II III Increasing Organic C Flux Density no m2 Forams 43 000 86 000 86 000 156 240 000 Macrofauna 9 10 000 16 21 000 38 55 000 H log2 Foram Macrofauna 5 1 4 6 5 5 4 8 4 6 1 7 2 1 2 8 Es100 Forams Macroauna 37 41 38 54 33 33 48 13 17 10 15 17 12 10 64 78 16 54 Rank 1 Dominance Forams 13 Macrofauna 7 9 Diversity Foram diversity mirrors that of metazoans nematodes polychaetes North Carolina Slope 40 Foraminifera 35 Diversity E S100 Polychaetes 30 25 20 15 10 0 Gooday et al 2001 50 100 Org C Flux g C m 2 y 1 150 200 Single sample often has 150 200 spp 63mm if well oxygenated 14 Trox Model Jorrisen et al 1995 Gooday 2003 Food controls foraminifera distributions and diversity at low organic enrichment levels oxygen controls at high organic levels van der Zwaan et al 1999 Jorissen 1999 Foraminifera from the Challenger Deep deepest point in the ocean 10 980 m Todo et al 2005 Science Single chambered nonCalcareous taxa dominate 15 FORAMINIFERAL DIVERSITY Kitazato Gooday Lowest diversity in the Challenger Deep Xenophyophores specialized foraminifera megafaunal 500 m only 100 species Common near continental margins high food supply Not recognized until 1972 thought to be sponges 16 Xenophyophore bearer of foreign bodies Phylum Superclass Class Order Sarcodina Rhizopoda Foraminifera Psamminida Stannomida Lifestyles Hard and soft substrate On Mn nodules and crusts ice rafted stones and biogenic substrates In sediments epifaunal and infaunal 17 Foram Xeno similarities 1 Can be large in size 2 Typical sizes for large epibenthic forams may be 1 4 cm length but some xenophyophore tests are up to 25 cm 3 Some foraminiferans and all xenophyophores appear to be multinucleate 4 Some foraminiferans and all xenophyophores produce fecal pellets called stercomata or stercomes These are 10 30 m in diameter and may be retained within the test In the case of xenophyophores they are packaged into string like masses called stercomare and are used as a structural component 5 Xenos and Forams feed with pseudopodia Features specific to Xenophyophores 1 Xenophyophores have an organic tubule system that encloses the protoplasm