Chpt 15 - Benthic 2016.ppt - CHAPTER 15 Animals of the...

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Unformatted text preview: CHAPTER 15 Animals of the Benthic Environment Chapter Overview Benthic communities include a variety of habitats. Littoral (intertidal) Rocky Sediments Continental shelf Florida Environments Coral reefs – require specific conditions Abyssal plain Hydrothermal vents support diverse communities that rely on chemosynthesis. Distribution of benthic organisms More benthic productivity beneath areas of high surface primary productivity 98% of marine species, mainly on continental shelves Affected by surface ocean currents Biomass matches surface chlorophyll distribution. Fig. Benthic rocky shores Epifauna Sessile - Attached to substrate (barnacles, 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 Intertidal Zone (rocky shore) Littoral zone – between average high and low tides Harsh conditions organisms must adapt to Drying out during low tide Strong wave activity Protection from predators Changing conditions – temperature, salinity, oxygen content Some species sessile Food Reproduction Competition for space to attach Intertidal zonation (rocky shore) Fig. 15.02 Intertidal zonation (rocky shore) Spray zone (supratidal) Avoid drying out Many animals have shells Few species of marine algae Predator avoidance Isopod Periwinkles cyanobacteria Intertidal zonation (rocky shore) High tide zone Must avoid drying - animals have shells Marine algae - rock weeds with thick cell walls Rocky intertidal zonation Middle tide zone More types of marine algae Crabs and mollusks Echinoderms – sea stars and urchins Soft-bodied animals Pisaster – sea star, mussel predator Abalone Intertidal (Rocky) – Middle tide zone Sea anemones Sea cucumber Hermit crab Brittle star Rocky intertidal - middle tide zone Sea Anemones Cnidaria – related to jellyfish and coral Nematocysts for capturing prey Pull into tube-shaped bodies above water pointreyesscience.wordpress.com Intertidal zonation (rocky shore) Low tide zone Abundant algae Many animals hidden by sea weed and sea grass Crabs abundant a/ Rocky Intertidal Tide pools Variety of algae Softbodied and shelled animals – snails, echinoderms (starfish, sea urchins), crabs Euryhaline - Organisms adapted to extreme changes caused by evaporation dzonoquaswhistle.blogspot.com/2007/06/cape-ki... Physical Environment of 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 Tidal flats - fine-grained, flat- lying, more stable than high energy sandy beach Sand beaches - ghost crabs Mud flats – fiddler crabs Benthic organisms on sediment-covered shores Similar intertidal zones Less species diversity Coquina with valves extended Greater number of organisms Mostly infauna – burrow into sediment Meiofana and Microbial communities Fig. 15.08 Sandy beaches Bivalve mollusks Annelid worms – sand worms Crustaceans - crabs Sand dollar Echinoderms Sand crab/sand flea Animals burrow Sea urchins, sand dollars Meiofauna – microscopic Meiofauna Ghost crab hiding Fig. 15.09 Sandy Beach Organisms Meiofauna Small, feed on bacteria Polychaete worms, mollusks, arthropods, nematodes (round worms). Mud flats Marsh grasses Sea grasses – (submerged) eelgrass and turtle grass common Bivalves and other mollusks Fiddler crabs Birds - feeding Fiddler crabs Shallow Offshore Communities Subtidal – continental shelf Rocky or sandy Kelp (Kingdom Protista) Associated with rocky seafloor and high energy coastline Holdfasts – anchor kelp Pneumatocysts – gas-filled, keep large species upright Holdfasts Shallow ocean floor Kelp forest (Kingdom Protista) Beds of giant brown bladder kelp and bull kelp Fast growing Highly productive ecosystems Shelter for variety of organisms Kelp bed distribution Fig.15.14c Shallow ocean floor Rocky benthic usually more diverse than sandy benthic Greater variation of habitat Protection from predators Lobster and crabs Variety of fish Benthic fish dorso-ventrally (top to bottom) flattened - Shallow ocean floor Florida and the Caribbean Less wave action – sandy/rocks Queen Conch Sea grasses and algae Conch and other large mollusks Spiny lobster Stingray Horse Conch Spiny lobster Worm rock reefs • Colonies of Sabellariid sand worms (Phragmatopoma caudata) form shallow reefs by cementing sand tubes together • St. Augustine to south end of Biscayne Bay – Bathtub Reef in St. Lucie Co. • Provide habitat for many organisms Coral reefs Coral reef - most coral polyps live in large colonies Feed with stinging tentacles Related to jellyfish Hard calcium carbonate structures Symbiosis of coral and algae Coral reefs made of algae, mollusks, foraminifers as well as corals Hermatypic coral - mutualistic relationship with algae – zooxanthellae (dinoflagellate) Algae provide food Corals provide nutrients ges Soft coral polyp (Lobophytum compactum). Green shows the polyp tissue, while the red shows the zooxanthellae. Coral reefs Coral reefs limited to: Warm (but not hot) seawater Under 30oC (86oF) Strong sunlight (for symbiotic algae) Strong waves or currents Clear seawater - low nutrients Normal salinity Hard substrate Coral reefs Most diverse of all marine ecosystems More diverse on western boundaries of oceans Tropical - surface circulation warmer water Fringe islands and shallower water Greatest diversity - western Pacific and Indian oceans Reef-building corals Fig. 15.18 Coral reef zonation Different types of corals at different depths Fig. Coral reef zonation . Importance of coral reefs 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 – 1/3 of species Reefs protect shorelines Great Barrier Reef from space - Crown-of-thorns starfish and reefs Crown-of-thorns sea star - eats coral polyps (Pacific ocean) Outbreaks (greatly increased numbers) decimate reefs Collecting of large shell of Pacific Triton’s trumpet – reduced population of a major predator of starfish Fig. 15.21 Coral reefs in decline 30% healthy today, 41% healthy in 2000 One third of corals – high risk of extinction Humans – greatest threat Anchor Destructive fishing practices Tourist collecting Boat anchors damage Cyanide “fishing” %20to%20Coral%20Reefs%20M4 Coral reefs in decline Pollution - Sewage and agricultural fertilizers increase nutrients in reef waters Hermatypic corals thrive at low nutrient levels Algae overwhelm at high nutrient levels – Smothered by algae Bioerosion of coral reef by algae-eating organisms Coral covered with macroalgae Parrot fish eating coral . jpg Humans and coral reefs Other problems Sediments from construction or dredging smother coral Fishing practices, harvesting - Overfishing Sedimentation Humans and coral reefs Coral bleaching Water that is too warm causes loss of symbiotic algae, the coral’s primary energy source. Elevated UV levels Can recover if condition is temporary Often occurs during El Nino events Coral bleaching Dots show sites of coral bleaching Normal and Bleached Coral Climate change/global warming Coral reefs are affected by climate change Increased storm activity – tears up coral reefs Sea level rise – affects light penetration Increased precipitation – lowers salinity Ocean temperature increase – causes coral bleaching Ocean acidification Dissolves coral Great Barrier Reef before and after Cyclone Ita (2014) Climate change/global warming Coral reefs are affected by climate change Increased CO2 causes acidification – corals dissolve Deep-Ocean Floor Communities Less known about than shallower water communities Expensive to explore the deep only accessible via dredge and some submersibles and ROVs Robotic technology for exploration editions/blacksmokers/images/large/am f Benthic organisms on the deep seafloor Most common habitat on Earth Little known habitat bathyal, abyssal, hadal zones Light absent below 1000 m (3300 feet) Temperature usually between − 1.8°C (28.8°F) and 3°C (37°F) About the same salinity Oxygen content relatively high Pressure can be enormous Bottom currents usually slow crab.jpg /01/Coryphaenoides_videograb.jpg Food sources in deep seafloor Most food sinks from surface waters Low supply and “patchy” Fig. 15.24 Deep sea benthos Deposit feeders Large filter feeding animals are rare (food scarce) Crinoids, sponges, sea cucumbers, deep-sea corals Predators – fish, sea stars, brittle stars Blind lobster Brittle stars and sea stars Crinoid ce/04benthon/dsbenthos.htm Deep sea coral phelia/background/biology/media/biology1_600.j Deep sea benthos Long appendages to move about in deep soft sediment Chimera Tripod fish Sea pig (sea cucumber) Giant sea spider Deep-Sea Hydrothermal Vent Communities Hydrothermal vent communities - Discovery – WHOI Alvin in 1977 Galapagos Rift in Pacific Ocean Surrounding water temp 8 –12°C (46–54°F) Much higher than normal deep sea temp Chimney vents, hot acidic water ? articles.view/articleNo/32523/title/Life-onthe-Ocean-Floor--1977/ Deep-Sea Hydrothermal Vent Communities Hydrothermal vent biocommunities Organisms previously unknown to science Unusually large for depth in ocean Black smokers – underwater chimney vents emit sulfides Deep-sea hydrothermal vent communities Unique communities Giant tube worms Giant clams and mussels Crabs and shrimp Microbial mats Predatory fish Life supported by chemosynthesis Chemosynthesis Microscopic archaea – thrive on hydrogen sulfide from vents Manufacture sugar from hydrogen sulfide, carbon dioxide, and dissolved oxygen Fig 15.27 Chemosynthesis Base of hydrothermal vent food chain Worms, clams and mussels – symbiotic relationship with archaea ml Global hydrothermal and cold seep chemosynthetic communities Fig. 15.26 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” “Dead whale hypothesis” – Dispersal of vent organisms Pelagic eggs/larvae disperse to other food patches or vent fields Possible dispersal to carcasses – support vent organisms Take years to decompose Use as "stepping stones “ Whale carcass with worms, sea cucumbers Low Temperature Chemosynthesis Chemosynthesis also occurs at low temperature seeps Hydrocarbon seeps Oil and gas seeps Hydrogen sulfide and/or methane Figure 15.31 Low-Temperature Seeps Hypersaline seeps - salinity ~46 ppt, rich in hydrogen sulfide Florida Escarpment – seeping water from limestone fractures Support a diverse community Fig 15.30 Low-Temperature Seep Biocommunities Subduction zone seeps Juan de Fuca plate Folded sedimentary rocks Chemosynthetic Archaea feed on methane Global hydrothermal and cold seep chemosynthetic communities Fig. 15.26 Climate changes in the Oceans Chapt 16 Pg 542-553 Increasing ocean temperatures Sea surface temps risen mostly since 1970 Deep waters showing increases Changes in the Oceans Changes in air and water circulation North Atlantic especially sensitive Melting glaciers – warmer poles Forces cold air further south over U.S. Warmer oceans More frequent and intense storms Changes to ocean thermohaline circulation Potential loss of oxygen to the deep sea resulting in anoxic bottom conditions nt/noaa-arctic-futures-site Dead crabs and fish at the bottom of the Baltic sea due to anoxic bottom conditions Dissolved carbon dioxide and ocean pH Ocean acidity increase Some atmospheric carbon dioxide dissolves in ocean water to become carbonic acid. Acidifies ocean Changes in the Oceans Ocean acidity increase Threatens calcifying organisms Coccolithophores Foraminifers Mollusks Sea urchins Corals Anything with a calcareous shell Fig 16.26 Changes in the Oceans Other predicted changes Reduced dissolved oxygen – increase in dead zones Change in ocean productivity Migration of mangroves Increased ocean stratification and stronger thermocline Decreased productivity due to diminished upwelling Decline in global phytoplankton biomass Florida’s mangroves migrating north Marine organisms unable to adapt to temperature changes Reducing Greenhouse Gases Human emissions contributing to excessive CO2 in Earth’s atmosphere Global engineering – attempts to counteract humancaused climate change Reducing sunlight reaching earth Removing human-caused greenhouse gases 1/feb/18/geo-engineering Reduce CO2 emissions IPCC - Intergovernmental Panel on Climate Change (1988) Kyoto Protocol (1997) – Intergovernmental Negotiating Committee of the UN Meeting negotiated in Kyoto, Japan The goal was to reduce worldwide greenhouse gas emissions to 5.2 percent below 1990 levels Most of the world’s industrialized nations (191) support the Kyoto Protocol. Notable exception - the United States, which releases more greenhouse gases than any other nation and accounts for more than 25 percent of those generated by humans worldwide. The U.S. signed the treaty (1998) To this date, but congress has failed to ratify it. Reducing greenhouse gases Greater fuel efficiency Alternative fuels Re-forestation Eliminate chlorofluorocarbons Ocean’s role in reducing CO2 Ocean’s biological pump CO2 incorporated in organisms and carbonate shells (tests) Stored as biogenous calcareous sediments and fossil fuels Ocean is repository or sink for CO2 Increases ocean acidity enough to affect organisms (corals) Fig 16.32 Ocean’s role in reducing CO2 Iron Hypothesis - add iron to fertilize ocean to increase productivity Increase phytoplankton, increase carbon dioxide removal from atmosphere Plankton die and fall to bottom, sequestering CO2 in sediment May not affect global CO2 levels significantly May cause unknown problems in ocean ecology Fig 16.34 What can you do to affect change? (See Afterword pg in text) Drive smart – keep your vehicle tuned and the tires properly inflated Make smart choices in vehicles Do you really need that 8 cylinder SUV? Go green – support non-fossil fuel energy Switch lights – use energy efficient fluorescent and LED lights Replace appliances with energy efficient models What you do to affect change? Properly insulate and weather strip your home Plant trees and protect plant communities Reduce, reuse and RECYCLE Be smart about how you consume water VOTE – be aware of the positions of your candidates Educate – yourself and your kids. Bad habits are often learned from parents Marine resources management Afterword – Pages 550-553 Public must see the fundamental need to manage and conserve our coastal resources Education - “In the end we conserve what we love. We love only what we understand. We will understand only what we are taught”. Multidisciplinary – partnership between business, politicians educational institutions and government scientists (DEP) - Marine resources management Coral reef and estuary management – protect breeding and nursery habitat of important fishery species provide and keep jobs Protect beaches and coral reefs as recreational resources tourist dollars Enforcement of regulations Monitor biophysical conditions – effects of climate change and pollution Fund applied research to improve resources and to better understand the physical, biological and chemical aspects of ocean systems Increase the number of MPA’s – Marine Protected Areas 8/ArticleID/11701/Simone-Alin-Monitoring-the-rapidly-changing-chemistry-of- Marine Protected Areas U.S. National Marine Sanctuaries 14 Marine protected areas (MPA) ~ 47,000 sq k (18,000 sq m) Includes the Florida Keys What can YOU do to reduce ocean pollution? Snip plastic six-pack rings and be careful what you do with fishing line Reduce use of laundry detergent, lawn fertilizers and pesticides Clean up after your pet Take care of vehicle leaks quickly Drive less, carpool For groceries - use fabric bags or recycle plastic bags What can you do to reduce ocean pollution? Don’t release balloons DON’T LITTER – All canals drain to the lagoon Volunteer for beach cleanup Inform and Educate others End of CHAPTER 15 Animals of the Benthic Environment ...
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