Common aquatic proxies

1. Common aquatic proxies Structural material Group diatoms chrysophytes sponges radiolaria foraminifera* ostracodes Silicates Carbonates *agglutinated forams have clastic, not carbonate tests

2. Diatoms Unicellular, eukaryotic, generally photosynthetic microorganisms encased in a cell wall impregnated with silica. They tolerate a wide range of thermal, pH and salinity conditions in aquatic habitats and wetland soils. photo: Yuki Sawai

3. Centric and pennate diatoms 2 2 1 3 2 1 1. Valve face 2. Mantle 3. Girdle (bands = cingula) 3

4. Diatoms(major groups based on cell morphology and ornamentation) Eucentric - circular valve outline; radially symmetrical valve ornamentation. Eccentric - bipolar or multipolar outline; radial symmetry. Araphid - bilateral symmetry to a central thickening (sternum). Monoraphid - bilateral symmetry ; sternum has fissure (raphe) on onevalve only. Naviculoid - bilateral symmetry; sternum has raphe on both valves. Cymbelloid - raphes on both valves; assymetric on either the longitudinal or transverse axis. Nitzschoid - raphes on both valves raised above valve on keel. Surirelloid - raphes on both valves raised above valve on wing. Epithemoid - raphes on both valves within a canal.

5. valve view colony in girdle view Eucentric diatoms Thalassiosira Aulacoseira lacustris

6. Araphid (e.g. “Fragilaria”)and monoraphid diatoms(e.g. Cocconeis) Epivalve (with raphe) Hypovalve ( no raphe)

7. Naviculoid diatomsPinnularia abaujensis Diploneis finnica Frustulia rhomboides

8. Cymbelloid diatoms Cymbella affinis Eunotioid diatoms Eunotia formica

9. keel Nitschzoid diatoms Epithemoid diatoms canal

10. Surirelloid diatoms www.marbot.gu.se/files/melissa/checklist/diatoms.html#list

11. Diatoms: taxonomic problems(e.g. freshwater and brackish Fragilariaceae) Round, Crawford & Mann (1990) Krammer & Lange-Bertalot (1991) Fragilaria Fragilariforma Pseudostaurosira Punctastriata Staurosira Staurosirella Opephora(*marine) Martyana Ctenophora Neosynedra Synedra Tabularia Asterionella Centronella Ceratoneis Diatoma Hannea Meridion Asterionella Centronella Ceratoneis Diatoma Fragilaria Meridion Opephora Synedra Tetracyclus Tabellaria Tabellariaceae

12. Image in light microscope “Fragilaria”morphology a b c SEM images a) Fragilariforma b) Staurosirella c) Punctastriata d) Staurosira e) Pseudostaurosira d e From: Round et al. (1990) The Diatoms. Cambridge U.P.

13. Diatoms: taxonomic problems - synonymies In Great Lakes catalogue (www.umich.edu/~phytolab/Great lakes/DiatomHomePage) as Oestrupia zachariasi In California Academy of Sciences catalogue (www.calacademy.org/research/diatoms)as Oestrupia bicontracta

14. Examples of applications of diatoms in palaeoenvironmental studies Sea-level change:western Scotland Palaeoseismology:Discovery Bay, WA Palaeolimnology:depth: Lake Oloiden, Kenya pH: Baby Lake, Ontario temperature: Längsee, Austria

15. Diatom record of sea-level change in an isolation basin on the west coast of Scotland

16. DiscoveryBay, WADiatom record of tsunamiinundation of marshes

17. Lake Oloiden, Kenya (salt-tolerant benthic, naviculoid) (planktonic centric)

18. Diatom-inferred pH change, Baby Lake, Ontario (1870-1990) pH 5 6 7 from: Dixit et al. (1992) Water , Air and Soil Pollution, 62, 75-87.

19. Late-Glacial summer surface water temperature, Längsee (548 m asl), Austria Pollen DiatomsSurface Water Temp from: Schmidt et al. (1998) Aquatic Sciences, 60, 56-88.

20. Chrysophytes Although it is difficult to distinguish species in LM, the resting spores of Chrysophytes may prove useful as supplementary sources of environmental information in freshwater habitats. Chrysophyte stomatocyst (resting spore)

21. Freshwater sponges (e.g. Heteromyenia sp.?) 1. sponge spicules and diatoms (Stump Lake, BC) 2. gemmosclere 3. mega and microscleres 1 3 2

22. Sponge palaeofaunas, 20 ka BP - PD (Jackson Pond, KY) * * H. latitientia now restricted to northern New England

23. Rhizoplegma borealia Radiolarians • marine unicellular protists; • siliceous skeletons in soft cytoplasm; lipid globules in cytoplasm (and spines?) enhance buoyancy; • planktonic: occur from surface to depths of several hundred meters; • size range = 2 - 30 mm diameter; • families distinguished by skeletal shapes; some groups are solitary, others colonial; • species abundance related to water temp., salinity, and nutrient status. Lophospyris pentagona Lamprocyclas maritalis source: www. radiolaria.org

24. An example of the application of radiolarians in palaeo-oceanographic studies Core 1019 from: Pisias et al (2001) Quat. Sci Rev., 20, 1561-1576

25. Radiolarian assemblages in the Pacific Ocean from: Pisias et al.(2001) Quat. Sci Rev., 20, 1561-1576. Max. factor loadings

26. Radiolarian assemblages in core 1019 (989 m water depth) YD T1 green line = GISP2 d18O record; black line=radiolarian record

27. Foraminifera Foraminifera are single-celled protists that live in all marine environments. They inhabit the sea floor (benthonic forms) or the surface layer of the oceans (planktonic forms). Most of the soft tissue of the cell of a foraminifer is enclosed within a test which may be composed of secreted organic compounds and mineral grains cemented together (agglutinated test), or secreted calcite or aragonite (calcareous test). The calcareous tests are divided, in part, into hyaline and porcellaneous types based on the orientation of the calcium carbonate crystallites comprising the test.

28. Examples of (1) agglutinated and (2) calcareous foraminifers (1) Textularia forquata (2) Elphidium excavatum length = 0.18 mm; breadth = 0.09 mm max. diam. = 0.48 mm; thickness = 0.20 mm foram photos and info. from http://www.cs.uwindsor.ca/meta-index/fossils/woop.html

29. “N. pachy left” Examples of applications of foraminifera in palaeoenvironmental studies: coiling and ocean temperature

30. Forams: “aplanktic” episodes in the Red Sea confirm eustatic lowstands from: Rohling et al. (1998) Nature, 394, 162-165. Low RSL = hypersaline Red Sea = no planktonic forams

31. Palaeo-temperature, core DSDP-609(N. Atlantic) based on “%N. pachy left” 100% 0%

32. Bensonocythere americana Ostracodes Ostracodes are crustaceans with two calcareous valves hinged along the dorsal margin to form a carapace which is commonly ovate or kidney-shaped. They have adapted to marine environments — oceans, estuaries and lagoons; hypersaline environments; freshwater environments — lakes, ponds, rivers and springs; and terrestrial environments such as the moist humus of forests. The majority of ostracodes are benthonic in habit. dorsal view lateral view source:www.cs.uwindsor.ca/meta-index/fossils/woop.html length = 0.69 mm height = 0.38 mm   width = 0.35 mm

33. Applications of ostracodes in Quaternary palaeoenvironmental research:Lake Manitoba during the Holocene Salinity (g/L) 1 2 3 4 from: Curry (1997) Can. J. Earth Sci., 34, 699-708.

34. Applications of ostracodes:changes in depth ranges (controlled by water temperature)record oceanographicconditions on Bahama Bank pores 4° cooler Krithe sp. from: Rodriguez-Lazaro & Cronin (1999) Palaeo3, 152, 339-364. 2° cooler

35. Aquatic proxies as sources of proxy data:advantages • short generation times; quick response to environmental change • many groups cosmopolitan (cf. regional floras and megafaunas) • in situ, not derived from surrounding terrestrial habitats, therefore representative of conditions within the water body, rather than the watershed.

36. Aquatic proxies as sources of proxy data:limitations • no ‘parent’ for reference material (cf. pollen & spores) • species concept often difficult to apply; • small forms hard to distinguish in LM; • unstable taxonomies; many synonyms; • meagre ecological information; • often responsive to a wide variety of inter-linked environmental stimuli (water temperature, conductivity, pH, nutrient status, depth); • small size leads to homogenization by currents, etc. (i.e. allochthonous components common in fossil assemblages).