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CHAPTER 15 Animals of the Benthic Environment

CHAPTER 15 Animals of the Benthic Environment. Distribution of benthic organisms. More benthic productivity beneath areas of high surface primary productivity Mainly on continental shelves Affected by surface ocean currents. Fig. 15.1. www.portfolio.mvm.ed.ac.uk/studentwebs/session2.

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CHAPTER 15 Animals of the Benthic Environment

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  1. CHAPTER 15 Animals of the Benthic Environment

  2. Distribution of benthic organisms • More benthic productivity beneath areas of high surface primary productivity • Mainly on continental shelves • Affected by surface ocean currents Fig. 15.1

  3. www.portfolio.mvm.ed.ac.uk/studentwebs/session2 Benthic organisms on rocky shores • Epifauna(on top) • Attached to substrate (e.g., marine algae) • Move on/over seafloor (e.g., crabs, snails) • Moderate diversity of species • Greatest animal diversity at tropical latitudes • Greatest algae diversity at mid-latitudes http://dnr.metrokc.gov/wlr/waterres

  4. Intertidal zonation (rocky shore) Fig. 15.2 a

  5. Intertidal zonation (rocky shore) Fig. 15.2b • Spray zone (supratidal) • Avoid drying out • Many animals have shells • Few species of marine algae Monterey Bay, CA www.mbari.org/staff/conn/botany/methods

  6. http://www.woodbridge.tased.edu.au/mdc/Species%20Register/Barnacle-Tetra.jpghttp://www.woodbridge.tased.edu.au/mdc/Species%20Register/Barnacle-Tetra.jpg Intertidal zonation (rocky shore) • High tide zone • Avoid drying out so animals have shells • Marine algae—rock weeds with thick cell walls http://www.ecology.org/ecophoto/algae/Thumbnails/Plant%20Images-10360.jpg

  7. http://www.dfw.state.or.us/mrp/shellfish/commercial/Images/flat_abalone.jpghttp://www.dfw.state.or.us/mrp/shellfish/commercial/Images/flat_abalone.jpg Abalone Intertidal zonation (rocky shore) • Middle tide zone • More types of marine algae • Soft-bodied animals Pisaster – sea star, mussel predator http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Mollusca/Bivalvia/Mytiloida/Mytilidae/Pisaster%20Predate%20mussels.jpg

  8. http://www.fisherycrisis.com/chondrus/fig32.JPG Intertidal zonation (rocky shore) • Low tide zone • Abundant algae • Many animals hidden by sea weed and sea grass • Crabs abundant in all intertidal zones

  9. http://bivalves.info/Donax_hanleyanus.jpg Benthic organisms on sediment-covered shores • Similar intertidal zones • Less species diversity • Greater number of organisms • Mostly infauna– burrow into sediment • Microbial communities Coquina (Donax) Coquina with valves extended http://www.theseashore.org.uk/theseashore/Resources%20for%20seashoreweb/Images%20for%20New%20Pages/Donax.JPG

  10. Intertidal zonation (sandy shore) Fig. 15.8

  11. Benthic organisms on sediment-covered shores • Energy level along shore depends on • Wave strength • Longshore current strength • Wave/current energy determines habitat… • Coarse boulder beaches • Sand beaches • Salt marshes • Mud flats • Fine-grained, flat-lying tidal flat more stable than high energy sandy beach

  12. Animals burrow Bivalve mollusks Annelid worms Crustaceans Echinoderms Meiofauna Sandy beaches Mole crab Ghost crab hiding Fig. 15-9 http://photography.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Photography/Images/POD/g/ghost-crab-hiding-760340-sw.jpg

  13. http://www.weeksbay.org/photo_gallery/shorebirds/SEMIPALMATED%20PLOVER.jpghttp://www.weeksbay.org/photo_gallery/shorebirds/SEMIPALMATED%20PLOVER.jpg Mud flats • Eelgrass and turtle grass common • Bivalves and other mollusks • Fiddler crabs http://www.sms.si.edu/irlspec/images/06PhotoContest/06DeWolfeH3.jpg http://www.lacoast.gov/articles/bms/1/3_mud_flat_ground_view.jpg

  14. http://www.teara.govt.nz/NR/rdonlyres/ED9A6951-7B98-4AD2-A6A0-CA633137BE7C/74562/p4595doc.jpghttp://www.teara.govt.nz/NR/rdonlyres/ED9A6951-7B98-4AD2-A6A0-CA633137BE7C/74562/p4595doc.jpg Shallow ocean floor • Continental shelf • Mainly sediment covered • Kelp forest associated with rocky seafloor • Also lobsters • Oysters http://www.ianskipworth.com/photo/pcd1742/kelp_forest_15_4.jpg http://www.lifesci.ucsb.edu/~c_white/images/Lobsters%20in%20San%20Diego.JPG

  15. Figure 15.14a,b

  16. Figure 15.14c

  17. Ever see a bivalve shell with a hole in it?

  18. http://www.h2o-mag.com/issue6/images_issue6/coral-01-copy.jpghttp://www.h2o-mag.com/issue6/images_issue6/coral-01-copy.jpg Coral reefs • Most coral polyps live in large colonies • Hard calcium carbonate structures cemented together by coralline algae www.gettankedaquariums.com www.mpm.edu/images

  19. Coral reefs • Coral reefs limited to • Warm (but not hot) seawater • Sunlight (for symbiotic algae) • Strong waves or currents • Clear seawater • Normal salinity • Hard substrate http://www.ee.bilkent.edu.tr/~aytur/pg www.waterfrontchattanooga.com/Newsroom/High_res

  20. Reef-building corals Fig. 15-17

  21. Symbiosis of coral and algae • Coral reefs made of algae, mollusks, foraminifers as well as corals • Hermatypic coral mutualistic relationship with algae – zooxanthellae • Algae provide food • Corals provide nutrients Soft coral polyp (Lobophytum compactum). Green shows the polyp tissue, while the red shows the zooxanthellae. www.bigelow.org/reefwatch2001/coral_reefs/images http://www.reefed.edu.au/explorer/images

  22. Coral reef zonation • Different types of corals at different depths Fig. 15.19

  23. http://www.sheppardsoftware.com/images/Oceania/factfile/GreatBarrierReef-EO.jpghttp://www.sheppardsoftware.com/images/Oceania/factfile/GreatBarrierReef-EO.jpg Importance of coral reefs Great Barrier Reef from space • Largest structures created by living organisms • Great Barrier Reef, Australia, more than 2000 km (1250 m) long • Great diversity of species • Important tourist locales • Fisheries • Reefs protect shorelines

  24. Humans and coral reefs • Activities such as fishing, tourist collecting, sediment influx due to shore development harm coral reefs • Sewage discharge and agricultural fertilizers increase nutrients in reef waters • Hermatypic corals thrive at low nutrient levels • Phytoplankton overwhelm at high nutrient levels • Bioerosion of coral reef by algae-eating organisms Coral covered with macroalgae http://daac.gsfc.nasa.gov/oceancolor/images/coral_reef_algae.jpg

  25. Other problems • Smoothering by dredging, runoff • Fishing practices, harvesting • Pollution • Global warming http://images.wri.org

  26. Large vs. small reef fish: Fishery management regulations such as minimum sizes allow fishermen to keep only the largest fish. As shown by the red snapper example, the largest fish produce the most eggs. One 24-inch red snapper produces the same number of eggs as 212 17-inch red snapper. So, by selectively removing the largest fish, the fishery removes the fish that have the greatest potential for producing more fish. ttp://oceanexplorer.noaa.gov/explorations/02sab/logs/aug05/media

  27. Crown-of-thorns starfish and reefs • Sea star eats coral polyps • Outbreaks (greatly increased numbers) decimate reefs Fig. 15.21

  28. Worm Reefs • Sabellariid worms (Phragmatopoma caudata) form shallow reefs • St. Augustine to south end of Biscayne Bay • Provide habitat for many organisms www.floridaoceanographic.org/environ/images www.stlucieco.gov/erd/threatened-endangered

  29. Adult worms (3/4 - 2 in. long) build reefs on limestone and coquina formations, jetties • Build sand hoods over tubes to reduce desiccation at low tide. • Protective tubes made of sand, joined to neighbors to build rigid, wave resistant structures. • 15,000 to 60,000 worms per m2 • Live up to 10½ years. • Thais (oyster drill) is an important predator

  30. http://www.amnh.org/nationalcenter/expeditions/blacksmokers/images/large/amnh19_18.jpghttp://www.amnh.org/nationalcenter/expeditions/blacksmokers/images/large/amnh19_18.jpg Benthic organisms on the deep seafloor • Little known habitat – only accessable via dredge and some submersibles and ROVs • Bathyal, abyssal, hadal zones • Little to no sunlight • About the same temperature • About the same salinity • Oxygen content relatively high • Pressure can be enormous • Bottom currents usually slow http://library.thinkquest.org/17297/images/alvin.gif http://www.whoi.edu/science/B/people/sbeaulieu/rad_patch_by_mound.jpg

  31. Food sources in deep seafloor • Most food sinks from surface waters • Low supply and “patchy” Fig. 15.22

  32. http://i.treehugger.com/images/2007/10/24/deep-sea%20hydrothermal%20vent-jj-001.jpghttp://i.treehugger.com/images/2007/10/24/deep-sea%20hydrothermal%20vent-jj-001.jpg Deep-sea hydrothermal vent biocommunities • First discovered 1977 • Chemosynthesis • Archaea use sea floor chemicals to make organic matter • Unique communities • Tube worms • Giant clams and mussels • Crabs • Microbial mats www.jamstec.go.jp/jamstec/organi/GOIN

  33. Figure 15.27

  34. Chemosynthesis • Archaea use sea floor chemicals to make organic matter Figure 15.25b

  35. Global hydrothermal vent fields Fig. 15.24

  36. Deep-sea hydrothermal vent biocommunities • Vents active for years or decades • Animals species similar at widely separated vents • Larvae drift from site to site • “Dead whale hypothesis”

  37. “Dead whale hypothesis” – Dispersal of vent organisms • Pelagic eggs/larvae disperse to other food patches or vent fields • Methane-bearing springs on continental shelves and slopes are more common than originally thought • Possible dispersal to carcasses – support vent organisms • Take years to decompose • Use as "stepping stones Whale carcass with worms, sea cucumbers www.mbari.org

  38. On whale bones, only the pinkish trunk of this cross-section of a female Osedax tubeworm is visible. The white blobs are ovaries where more than 100 dwarf male tubeworms can live inside the female. Symbiotic bacteria give the tubeworm's roots their greenish color. Bacteria in the roots of Osedax produce nutrients by processing the fats and lipids in the bones of whales. www.geotimes.org/aug04

  39. Figure 15.C Fish carcass On ocean floor

  40. Deep-sea hydrothermal vent biocommunities • Life may have originated at hydrothermal vents • Chemosynthesis also occurs at low temperature seeps • Hypersaline seeps • Hydrocarbon seeps • Subduction zone seeps

  41. Figure 15.28 & 15.29

  42. Figure 15.29b

  43. http://oceanworld.tamu.edu/resources/oceanography-book/Images/Azam-(1998)-2.gifhttp://oceanworld.tamu.edu/resources/oceanography-book/Images/Azam-(1998)-2.gif Beneath the sea floor • Deep biosphere • Microbes live in porous sea floor • Might represent much of Earth’s total biomass In may 2008, prokaryotes were reported in mud cores extracted from between 860 to 1626 meters beneath the sea floor off Newfoundland. Cells were 100-1000 fold denser than in terrestrial cores of similar depth and about 5-10% of the cells were dividing. http://environment.newscientist.com/channel/earth/deep-sea/dn13960-huge-hidden-biomass-lives-deep- beneath-the-oceans.html

  44. Misconceptions • Scientists have already studied all the Earth’s systems so there will not be any new discoveries. • Science always has exact answers.

  45. Ocean Literacy Principles • 3e. - The ocean dominates the Earth’s carbon cycle. Half the primary productivity on Earth takes place in the sunlit layers of the ocean and the ocean absorbs roughly half of all carbon dioxide added to the atmosphere. • 5a. - Ocean life ranges in size from the smallest virus to the largest animal that has lived on Earth, the blue whale. • 5b. - Most life in the ocean exists as microbes. Microbes are the most important primary producers in the ocean. Not only are they the most abundant life form in the ocean, they have extremely fast growth rates and life cycles. • 5c. - Some major groups are found exclusively in the ocean. The diversity of major groups of organisms is much greater in the ocean than on land. • 5d. - Ocean biology provides many unique examples of life cycles, adaptations and important relationships among organisms (symbiosis, predator-prey dynamics and energy transfer) that do not occur on land. • 5e. - The ocean is three-dimensional, offering vast living space and diverse habitats from the surface through the water column to the seafloor. Most of the living space on Earth is in the ocean. • 5f. - Ocean habitats are defined by environmental factors. Due to interactions of abiotic factors such as salinity, temperature, oxygen, pH, light, nutrients, pressure, substrate and circulation, ocean life is not evenly distributed temporally or spatially, i.e., it is “patchy”. Some regions of the ocean support more diverse and abundant life than anywhere on Earth, while much of the ocean is considered a desert. • 5g. - There are deep ocean ecosystems that are independent of energy from sunlight and photosynthetic organisms. Hydrothermal vents, submarine hot springs, methane cold seeps, and whale falls rely only on chemical energy and chemosynthetic organisms to support life. • 5h. - Tides, waves and predation cause vertical zonation patterns along the shore, influencing the distribution and diversity of organisms. • 5i. - Estuaries provide important and productive nursery areas for many marine and aquatic species.

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