This lecture will help you understand:

2. The marine environment Major marine ecosystems Human uses of marine resources Human impacts on the marine environment The state of ocean fisheries Marine protected areas and reserves This lecture will help you understand: Schooling Marine fish

3. Central Case: collapse of the cod fisheries • No fish has more impact on human civilization than the Atlantic cod • Eastern Canadians and U.S. fishermen have fished for cod for centuries since in early 1500s • Large ships and technology have destroyed the cod fishery (Trawling in particular) • Even protected stocks are not recovering Massachusetts cod fishermen haul in a dwindling catch

4. Cod are groundfish • They live or feed along the bottom • Halibut, pollock, flounder • Cod eat small fish and invertebrates • They grow to 60-70 cm long and can live 20 years • Inhabit cool waters on both sides of the Atlantic There are 24 stocks (populations) of cod Dwindles in 1980s - Trawling (p459) destroyed underground habitats

5. Oceans cover most of the Earth’s surface • The oceans influence global climate, team with biodiversity, facilitate transportation and commerce, and provide resources for us • They cover 71% of Earth’s surface and contain 97% of Earth’s surface water – Major Hydrosphere • Oceans influence the atmosphere, lithosphere, and biosphere

6. The oceans contain more than water • Ocean water is 96.5% water • Plus, ions of dissolved salts • Evaporation removes pure water and leaves a higher concentration of salt • Nutrients (nitrogen and phosphorus) • Dissolved gas: Oxygen is added by plants, bacteria, and atmospheric diffusion

7. Ocean water is vertically structured • Temperature declines with depth • Heavier (colder & saltier) water sinks • Light (warmer & less salty) water remains near the surface • Temperatures are more stable than land temperatures • Water’s much higher heat capacity than land or air It takes much more heat to warm water than air (~4x ) (i.e., larger specific heat: 1 cal/(oCg)=4.184J/(K g) ) • Oceans regulate the earth’s climate • They absorb and release heat • Ocean’s surface circulation

8. The ocean has several layers • Surface zone (~150 m): ~2% • Warmed by sunlight and stirred by wind, Consistent water density • Pycnocline(~1,000m): ~18% below the surface zone • Density increases rapidly with depth • Deep Zone: ~ 80% below the pycnocline • Dense, sluggish water • Unaffected by winds, storms, sunlight, & temperature

9. Ocean water flows horizontally in currentsConvection • Currents: the ocean is composed of vast riverlike flows • Driven by density differences, heating and cooling, gravity (Tide), and wind • Influence global climate • Transport heat, nutrients, pollution, and the larvae of many marine species • Some currents such as the Gulf Stream are rapid and powerful • The warm water moderates Europe’s climate

10. Ocean Currents : A Big Picture

11. The upper waters of the oceans flow in currents

12. Surface winds and heating create vertical currents • Upwelling: where surface current diverge, the vertical flow of cold, deep water towards the surface - Rich in nutrient from bottom, thus giving high primary productivity and lucrative fisheries • Also occurs where strong winds blow away from, or parallel to, coastlines • Downwellings:where surface currents come together (converge), oxygen-rich surface water sinks - transport warm water rich in gas (O2) for deep-water life. Start (11/20/08)

13. Seafloor topography can be rugged and complex • The seafloor consists of… • Underwater volcanoes • Steep canyons, trenches • Mountain range • The planet’s longest range is under water • Mounds of debris • Some flat areas Diverging Mid-Atlantic Ridge: N/S Amarican Plate and African Plate (Cf. p200)

14. Profile of the ocean

15. Regions of ocean differ greatly • Some zones support more life than others • Photic Zone: well-lighted top layer that supports high primary productivity (~ limnetic zone of a lake) • Pelagic Zone : habitats and ecosystems occurring between the ocean’s surface and floor (~ profundal zone of a lake) • Benthic Zone : habitats and ecosystems occurring on the ocean floor

16. Open ocean systems vary in biodiversity • Microscopic phytoplankton constitute the base of the marine food chain in the pelagic zone: Producers • Algae, cyanobacteria and protists • These organisms feed zooplankton (Primary Consumer) • Which then feeds fish, jellyfish, whales, etc. (Secondary Consumers) • Predators at higher trophic levels include larger fish, sea turtles, sharks, and fish-eating birds (Tertiary Consumer)

17. Marine Ecosystems: • Kelp Forest Ecosystem : • Deep Ocean Ecosystem : • Coral Reef Ecosystem : Coastal Ecosystems: • Intertidal (Littoral) Ecosystem : • Salt Marsh Ecosystem : • Mangrove Forest Ecosystem : • Estuary Ecosystem :

18. Kelp forests: Underwater Forests harbor many organisms: • Kelp: (~60 m) large, dense, brown algae growing from the floor of continental shelves (Cf.: Giant Sequoia ~ 80m) • Dense strands form kelp forests along temperate coasts • Shelter and food for organisms • Absorbs wave energy and protects shorelines from erosion • Eaten by people • Alginates serve as thickeners in cosmetics, paints, paper, and soaps → The Keystone species ?

19. Deep Ocean Ecosystem: • Animals adapt to extreme water pressure and the absence of light • Scavenge carcasses or organic detritus • Some are predators, while others have mutualistic relationships with bacteria • Some species carry bacteria that produce light chemically by bioluminescence (What’s the common example in land?) • Hydrothermal vents support tubeworms, shrimp, and other chemosynthetic species (The Black Smoker, p104, Fig. 4.18) Anglerfish lures prey with a glowing organ

20. Coral reefs are treasure troves of biodiversity • Located in shallow subtropical and tropical waters needs warm, clean pollution free, O2 rich water • Corals:tiny colonial marine organisms (animal) • Related to sea anemones and jellyfish • Remain attached to rock or existing reef and capture passing food with stinging tentacles • Derive nourishment from symbiotic photosynthetic brown algae, zooxanthallae • Extract CO2 ( in a form of CO32-) from sea water to build reef limestone (CaCO3)

21. Coral reefs are treasure troves of biodiversity • Corals:tiny colonial marine organisms (animal) • Related to sea anemones and jellyfish • Remain attached to rock or existing reef and capture passing food with stinging tentacles

22. Coral reefs consist of millions of corals • Coral reef: a mass of calcium carbonate composed of the skeletons of corals • Consists of millions of densely packed individuals • Protect shorelines by absorbing waves • Innumerable invertebrates and fish species find food and shelter in reef nooks and crannies

23. Coral reefs are in worldwide decline • Coral bleaching: occurs when zooxanthellae leave the coral • Coral lose their color and die, leaving white patches • From climate change, pollution, or unknown natural causes • Nutrient pollution causes algal growth, which covers coral • Divers damage reefs by using cyanide to capture fish • Acidification of oceans deprives corals of necessary carbonate ions for their structural parts • Limestone becomes part of lithosphere storage of C (or CO2) • Destruction of coral will cause more CO2 in the atmosphere End (11/20/08)

24. Intertidal Zones Ecosystem undergo constant change • Intertidal (littoral) ecosystems : where the ocean meets the land • between the uppermost reach of the high tide and the lowest limit of the low tide • Tides: periodic rising and falling of the ocean’s height due to the gravitational pull of the sun and moon • Intertidal organisms spend part of their time submerged in water and part of their time exposed to sun and wind

25. A typical intertidal zone

26. Intertidal zones are a tough place to live • But they have remarkable diversity • Rocky shorelines, crevices, pools of water (tide pools) • Anemones, mussels, crabs barnacles, urchins, sea slugs, and, starfish • Temperature, salinity, and moisture change dramatically from high to low tide • Sandy intertidal zones have slightly less biodiversity

27. Salt Marsh Ecosystems occur widely • Salt marsh: occur along coasts at temperate latitude • Tides wash over gently sloping, sandy, silty substrates • High primary productivity • Critical habitat for birds and commercial fish and shellfish species • Like any wetlands, Filter pollution • Stabilize shorelines against storm surges

28. People have changed and destroyed salt marshes for development • We lose key ecosystem service • Flooding worsens Tidal Creeks and Benches

29. Mangrove Forests Ecosystem: line coasts • In tropical and subtropical altitudes, these tropical evergreen replace salt marshes along sandy coasts • Mangroves: trees w/ unique roots • Curve upwards for O2 • Curve downwards for support • Nurseries for commercial fish and shellfish • Nesting areas for birds • Food, medicine, tools, construction materials

30. Mangrove forests have been destroyed • Development for residential, commercial, and recreational uses • Shrimp farming • Half the world’s mangrove forests are gone • Once destroyed, coastal areas no longer • Slow runoff • Filter pollutants • Retain soil • Protect communities against storm surges • We are protecting only 1% of remaining mangroves

31. Estuary Ecosystems: where fresh and salt water meet • Estuaries: water bodies where rivers flow into the ocean • Wide fluctuations in salinity • Critical habitat for shorebirds and shellfish • Transitional zone for anadromous (spawn in freshwater, mature in salt water) fishes (example?) • Affected by development, pollution, habitat alteration, and overfishing

32. Oceans provide transportation routes • Humans have interacted with oceans for thousands of years • Moving people and products over vast distances • Accelerated global reach of cultures • Has substantial impact on the environment • Moves resources around the world • Ballast water transplants organisms, which may become invasive

33. We extract minerals from oceans • Minerals such as sand, gravel, sulfur, calcium carbonate, and silica • Rich deposits of copper, zinc, silver, and gold • Magnesium: dissolved (Mg2+ , third most ions) H2O(l)+ CaO(s) → Ca2+(aq) + 2OH-(aq) Mg2+(aq) + 2OH-(aq) → Mg(OH)2(s) Mg(OH)2(s) +2HCl(aq) → MgCl2(aq) + 2H2O(l) MgCl2(aq) → MgCl2(s) → MgCl2(l) → Mg(s)+ Cl2(g) evaporate H2O melt Electrolyze • Manganese nodules are scattered along the ocean’s floor • But, they are too hard to currently mine

34. Marine pollution threatens resources • Even into the mid-20th century, coastal U.S. cities dumped trash and untreated sewage along their shores • Oil, plastic, chemicals, excess nutrients make their way from land into oceans • Raw sewage and trash from cruise ships • Abandoned fishing gear from fishing boats In 2006, 359,000 Ocean Conservancy volunteers from 66 nations picked up 3.2 million kg (7 million lbs.) of trash

35. Nets and plastic debris endangers marine life • Plastic items dumped into the sea harm or kill wildlife • Plastic is non-biodegradable • Drifts for decades • Washes up on beaches • Wildlife eat it or get entangled and die • Marine debris affects people • Equipment damage • The 2006 Marine Debris Research, Prevention and Reduction Act

36. Oil pollution comes from spills of all sizescausing serious environmental problems • Major oils spills make headlines 1989 March 24, 1989; 11 M gal the Exxon Valdez hit a reef 2010, April 20th : 200 M gal the BP Offshore Station Explode • Most pollution comes from small sources, such as Boat leakage & runoff from land Naturally occurring leaks from the seabed • Oil spills coat & poison wildlife

37. Oil pollution has decreased • Governments have implemented more stringent regulations • The U.S. Oil Pollution Act of 1990 • Creates a $1 billion prevention and cleanup fund • Requires all ships have double hulls by 2015 • Recently, oil spills have decreased • The oil industry resists such safeguards

38. Toxic pollutants contaminate seafood • Mercury contamination • From coal combustion and other sources • Bioaccumulates and biomagnifies • Dangerous to young children and pregnant or nursing mothers • Avoid eating swordfish, shark, and albacore tuna • Eat seafood low in mercury (catfish, salmon, canned light tuna) • Avoid seafood from areas where health advisories have been issued

39. Emptying the oceans • We are placing unprecedented pressure on marine resources • Half the world’s marine fish populations are fully exploited • 25% of fish population are overexploited and heading to extinction • Total fisheries catch leveled off after 1998, despite increased fishing effort • It is predicted that populations of all ocean species we fish for today will collapse by the year 2048

40. The total global fisheries catch has increased

41. We have long overfished • People began depleting sea life centuries ago • Some species hunted to extinction: Steller’s sea cow, Atlantic gray whale, Caribbean monk seal • Overharvesting of Chesapeake Bay oyster beds led to the collapse of its fishery, eutrophication, and hypoxia • Decreased sea turtle populations causes overgrowth of sea grass and can cause sea grass wasting disease • People never imagined that groundfish could be depleted • New approaches or technologies increased catch rates

42. Fishing has industrialized Factory Fishing : highly industrialized, huge vessels use powerful technologies to capture fish in huge volumes - process and freeze their catches while at sea • Driftnets for schools of herring, sardines, mackerel, sharks • Longline fishing for tuna and swordfish • Trawling for pelagic fish and groundfish →devastate deep ocean ecosystem

43. Fishing practices kill nontarget animals • By-catch: the accidental capture of animals • Driftnetting drowns dolphins, turtles, and seals • Fish die from air exposure on deck • Banned or restricted by many nations • Longline fishing kills turtles, sharks, and albatrosses • 300,000 seabirds die each year • Bottom-trawling destroys communities • Likened to clear-cutting and strip mining

44. Modern fishing fleets deplete marine life rapidly • Grand Banks (p444) cod have been fished for centuries • Catches more than doubled with immense industrial trawlers • Record-high catches lasted only 10 years

45. Industrialized fishing depletes populations • Catch rates drop precipitously with industrialized fishing • 90% of large-bodied fish and sharks are eliminated within 10 years • Populations stabilize at 10% of their former levels • Marine communities may have been very different before industrial fishing • Removing animals at higher trophic levels allows prey to proliferate and change communities

46. Oceans today contain only one-tenth of the large-bodied animals they once did

47. We are “fishing down the food chain” • Figures on total global catch do not relate the species, age, and size of fish harvested • As fishing increases, the size and age of fish caught decline • 10-year-old cod, once common, are now rare • As species become too rare to fish, fleets target other species • Shifting from large, desirable species to smaller, less desirable ones • Entails catching species at lower trophic levels

48. Consumer choices influence fishing practices • Buy ecolabeled seafood • Dolphin-safe tuna • Consumers don’t know how their seafood was caught • Nonprofit organizations have devised guides for consumers • Best choices: farmed catfish and caviar, sardines, Canadian snow crab • Avoid: Atlantic cod, wild-caught caviar, sharks, farmed salmon

49. We can protect areas in the ocean • Marine protected areas (MPAs) : established along the coastlines of developed countries • Still allow fishing or other extractive activities • Marine reserves : areas where fishing is prohibited • Leave ecosystems intact, without human interference • Improve fisheries, because young fish will disperse into surrounding areas • Many commercial, recreation fishers, and businesses do not support reserves

50. Conclusion • Oceans cover most of our planet and contain diverse topography and ecosystems • We are learning about the oceans and coastal environments, intensifying our use their resources and causing severe impacts • Setting aside protected areas of the ocean can serve to maintain natural systems and enhance fisheries • We may once again attain the ecological systems that once flourished in our waters