This lecture will help you understand:

This lecture will help you understand:
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 Schooling Marine fish

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

They live or feed along the bottom Halibut, pollock, flounder
Cod are groundfish They live or feed along the bottom Halibut, pollock, flounder Cod eat small fish and invertebrates They grow to 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

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

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

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/(oC g)=4.184J/(K g) ) Oceans regulate the earth’s climate They absorb and release heat Ocean’s surface circulation

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

Ocean water flows horizontally in currents: Convection
Currents: the ocean is composed of vast riverlike flows Driven by density differences, heating/cooling, gravity, and wind Influence global climate and El Niño and La Niña 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

Ocean water flows horizontally in currents Convection
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

Ocean Currents : A Big Picture

The upper waters of the oceans flow in currents

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)

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)

Understanding underwater geography
Maps show… Bathymetry: the measurement of ocean depths Topography: the physical geography or the shape and arrangement of landforms Continental shelves: gently sloping areas that underlie the shallow waters bordering continents Shelf-slope break: sudden drop off of the continental shelf Continental slope: connects the continental shelf to the ocean floor

Profile of the ocean

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

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)

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

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 ?

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

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) Corals are marine organisms in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps." The group includes the important reef builders that inhabit tropical oceans, which secrete calcium carbonate to form a hard skeleton. A coral "head," which appears to be a single organism, is a colony of myriad genetically identical polyps. Each polyp is typically only a few millimeters in diameter. Over many generations the colony secretes a skeleton that is characteristic of the species. Individual heads grow by asexual reproduction of individual polyps. Corals also breed sexually by spawning. Polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon. Although corals can catch small fish and animals such as plankton using stinging cells on their tentacles, most corals obtain the majority of their energy and nutrients from photosynthetic unicellular algae called zooxanthellae. Such corals require sunlight and grow in clear, shallow water, typically at depths shallower than 60 metres (200 ft). Corals can be major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the enormous Great Barrier Reef off the coast of Queensland, Australia. Other corals do not have associated algae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3,000 metres (9,800 ft).[3] Examples live on the Darwin Mounds located north-west of Cape Wrath, Scotland. Corals have also been found off the coast of the U.S. in Washington state and the Aleutian Islands in Alaska.

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 Corals are marine organisms in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps." The group includes the important reef builders that inhabit tropical oceans, which secrete calcium carbonate to form a hard skeleton. A coral "head," which appears to be a single organism, is a colony of myriad genetically identical polyps. Each polyp is typically only a few millimeters in diameter. Over many generations the colony secretes a skeleton that is characteristic of the species. Individual heads grow by asexual reproduction of individual polyps. Corals also breed sexually by spawning. Polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon. Although corals can catch small fish and animals such as plankton using stinging cells on their tentacles, most corals obtain the majority of their energy and nutrients from photosynthetic unicellular algae called zooxanthellae. Such corals require sunlight and grow in clear, shallow water, typically at depths shallower than 60 metres (200 ft). Corals can be major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the enormous Great Barrier Reef off the coast of Queensland, Australia. Other corals do not have associated algae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3,000 metres (9,800 ft).[3] Examples live on the Darwin Mounds located north-west of Cape Wrath, Scotland. Corals have also been found off the coast of the U.S. in Washington state and the Aleutian Islands in Alaska.

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

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)

Deepwater coral reefs exist
They thrive in waters outside the tropics On ocean floor at depths of m ( ft) Occur in cold-water areas Little is known about these reefs Already, many have been badly damaged by trawling Some reefs are now being protected

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

A typical intertidal zone

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

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 a

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

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

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

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

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

We extract energy from oceans
Crude oil and natural gas Oil spills damage fisheries Methane hydrate: a potential energy source Ice-like solid methane embedded in water crystals A vast supply, but research needs to be done Renewable energy sources, such as waves, tides, heat

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 Mg: firebomb, photoflash, marine flare Epsom Salt (MgSO4, laxative) Milk of Magnesia (M(OH)2), “ )

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

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

Major oils spills make headlines 1989 March 24, 1989; 11 M gal
Oil pollution comes from spills of all sizes causing 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

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

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

Excess nutrients cause algal blooms
Harmful algal bloom : nutrients increase populations of algae that produce powerful toxins Red tide : algal species produce reddish pigments that discolor water Illness and death to wildlife and humans Economic losses to fishing industries and beach tourism Reduce runoff and prevent consumption of affected organisms

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

The total global fisheries catch has increased

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

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

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

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

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

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

Several factors mask declines
Industrialized fishing has depleted stocks, global catch has remained stable for the past 20 years Fishing fleets travel longer distances to reach less-fished portions of the ocean Fleets spend more time fishing and have been setting out more nets and lines, increasing effort to catch the same number of fish Improved technologies: faster ships, sonar mapping, satellite navigation, thermal sensing, aerial spotting Data supplied to international monitoring agencies may be false

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

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

Fisheries management Based on maximum sustained yield Maximal harvest while keeping fish available for the future Managers may limit the harvested or restrict gear used Despite management, stocks have plummeted It is time to rethink fisheries management Ecosystem-based management Shift away from species and toward the larger ecosystem Consider the impacts of fishing on habitat and species interactions Set aside areas of oceans free from human interference

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

Reserves work for both fish and fisheries
Found that reserves do work as win-win solutions Overall benefits included… Boosting fish biomass Boosting total catch Increasing fish size Benefits inside reserve boundaries included… Rapid and long-term increases in marine organisms Decrease mortality and habitat destruction Lessen the likelihood of extirpation of species

Areas outside reserves also benefit
Benefits included… A “spillover effect” when individuals of protected species spread outside reserves Larvae of species protected within reserves “seed the seas” outside reserves Improved fishing and ecotourism

How should reserves be designed?
20-50% of the ocean should be protected in no-take reserves How large? How many? Where? Involving fishers is crucial fisheries in coming with these answers

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

QUESTION: Review An “upwelling” is defined as….
The vertical flow of cold, deep water towards the surface The vertical flow of warm, deep water towards the surface The vertical flow of cold, shallow water towards the bottom The vertical flow of warm, deep water towards the bottom Answer: a

QUESTION: Review The area of an ocean that contains open water that receives sunlight is called the _______zone. Littoral Photic Pelagic Benthic Answer: b

QUESTION: Review _____ is defined as “large, dense, brown algae growing from the floor of continental shelves.” Coral Red tide Bottomfish Kelp Answer: d

QUESTION: Review Coral bleaching occurs when …. Corals reproduce
Fish move into coral reefs Zooxanthellae leave the coral Coral reefs expand their range Answer: c

QUESTION: Review An area where rivers flow into the ocean is called a(n) …? Estuary Mangrove swamp Salt marsh Coral reef Answer: a

QUESTION: Review Which of the following does not mask the decline of fisheries? Fishing fleets travel longer distances Fishing fleets spend more time fishing Fishing fleets use traditional methods of fishing Data supplied to monitoring agencies may be false Answer: c

QUESTION: Review Marine reserves have all the following benefits except: Fishing increases in the reserve The size of fish increases Larvae can “seed” areas outside the reserve Decreased mortality and habitat destruction Answer: a

QUESTION: Interpreting Graphs and Data
What does this graph show about the future of global fisheries catch? China will be a major player in applying fishing pressure China will be player a smaller role in applying fishing pressure The world will decrease its fishing pressure The U.S. is not included in this graph Answer: b

QUESTION: Interpreting Graphs and Data
Which conclusion can you draw from this graph? Oceans today contain far fewer fish Oceans today contain far more fish It is easier to find fish today There is little correlation between fishing and fish stocks Answer: b

QUESTION: Viewpoints If a developer wants to build a community on an estuary, providing jobs but eliminating the marsh, what should be done? Let the developer build; we need the jobs Let the developer build, but make him/her pay for any damage from storms Let the surrounding landowners vote whether to let the developer build Prevent the development; the potential damage is too great Answer: any

QUESTION: Viewpoints Do you plan to alter your decisions about eating seafood? Yes; I will be more selective about what I eat No; I will continue to eat the same type and amount of seafood as always Answer: any

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