Miller Chapter 11 Review
I.
Chapter 11: Sustaining Aquatic Biodiversity and Ecosystem Services
a. 11-1: What are the Major Threats to Aquatic Biodiversity and Ecosystem Services?
i. We have explored about 5% of the earth’s interconnected oceans and know
relatively little about marine biodiversity and its many functions
ii. Three general patterns related to marine biodiversity:
1. The greatest marine biodiversity occurs around coral reefs, in estuaries, and
on the deep-ocean floor.
a. An area of coral reef roughly equal to the size of a city block provides
economic and ecosystem services worth more than $1.2 million a year
2. Biodiversity is greater near the coasts than in the open seas because of the
larger variety of producers and habitats in coastal areas
3. Biodiversity is generally greater in the bottom region of the ocean than in the
surface region because of the larger variety of habitats and food sources on
the ocean bottom
a. The deepest part of ocean, where sunlight does not penetrate is the
planet’s least explored environment
iii. HIPPCO
1. H (Habitat loss and degradation)
a. Ocean acidification – the rising levels of acid in ocean waters due to
their absorption of carbon dioxide from the atmosphere
b. Freshwater – main causes are the damming of rivers and excessive
withdrawal of river water for irrigation and urban water supplies
i. Destroy aquatic habitats, degrade water flows, and disrupt
freshwater biodiversity
c. Vacuuming the seas decreases marine biodiversity and degrading
important marine ecosystem services
2. I (Invasive – Nonnative Species)
a. The deliberate or accidental introduction of hundreds of harmful
invasive species
b. Bioinvaders are displacing or causing the extinction of native species
and disrupting ecosystem services and human economics
i. Many of these invaders arrive in ballast water that is stored in
tanks in large cargo ships to keep them stable.
1. Even when ballast water is flushed from an oceangoing
ship’s tank before it enters a harbor – a measure now
required in many ports
a. Example: East coast of N. America is the lionfish
native to weastern Pacific Ocean
3. P (Population growth)
a. About 80% of the world’s people were living along or near seacoasts,
mostly in large coastal cities
4. P (Pollution)
a. Toxic pollutants from industrial and urban areas can kill some forms
of aquatic life by poisoning them
5. C (Climate change)
a. A rise in sea level would destroy more shallow coral reefs, swamp
some low-lying islands, drown many highly productive coastal
wetlands, and put many coastal areas such as a large part of the U.S.
Gulf and East Coasts underwater
b. Warmer and more acidic ocean water is also stressing phytoplankton
i. Phytoplankton - Produce half of earth’s oxygen and absorb a
great deal of the carbon dioxide that we are adding to the
atmosphere through the burning of fossil fuels and other
activities
c. Warmer, more acidic ocean waters make it harder for these plankton
to absorb their critical nutrients such as iron
6. O (Overexploitation)
a. Overfishing
iv. Fishery – a concentration of a particular wild aquatic species suitable for
commercial harvesting in a given ocean area or inland body of water.
1. Human demand for seafood has been met historically through fishing --- and
the demand has now become unsustainable.
2. Research indicated that modern industrial fishing has been a key factor in the
depletion of up to 80% of the population of some wild fish species in only 1015 years.
a. Trawlers – catch on or near the ocean floor – destroy vast areas of
ocean bottom habitats, often catch endangered sea turtles causing
them to drown
b. Purse-Seine Fishing – used to catch surface-dwelling species such as
tuna, mackerel, anchovies, and herring
i. Killed large number of dolphins that swim on the surface above
schools of tuna
c. Long-Lining – which involves putting out lines up to 100km long hung
with thousands of baited hooks to catch swordfish, tuna, sharks, and
ocean-bottom species such as halibut and cod
i. Also hook and kill large numbers of sea turtles, dolphins, and
seabirds
d. Drift-Net Fishing – fish are caught by drifting nets that can hang as
deep as 15 meters (50ft) below the surface
i. Kill large quantities of unwanted fish (bycatch) along with
marine mammals, seabirds, and sea turtles
ii. Abandoned and lost nets known as ghost nets float beneath the
surface in many areas, trapping and drowning aquatic animals
for years before they finally sink or are recovered
v. Fishprint – defined as the area of ocean needed to sustain the fish consumption of an
average person, a nation, or the world
1. Commercial Extinction – which occurs when it is no longer profitable to
continue harvesting the affected species
a. Overfishing can result in only a temporary depletion of fish stocks, as
long as depleted areas and fisheries are allowed to recover
b. Depleted fisheries may not recover as jellyfish and other invasive
species move in and take over their food webs
vi. One result of the increasingly efficient global hunt for fish is that larger individuals
of commercially valuable wild species – including cod, marlin, swordfish, and tuna –
are becoming scarce
1. Tuna Ranching – which schools of half-grown Atlantic Bluefin and other tuna
are herded by the thousands into underwater pens and towed to areas where
they are help and fattened for slaughter
2. Whale harvesting in international waters has followed the classic pattern of
tragedy of the commons
vii. Case Study: Jellyfish
1. Often are found in large swarms or blooms of thousands even millions of
individuals
2. Have been rising and more frequent jellyfish stings have had a harmful
economic effect on a number of popular tourist beach areas
a. Often cause beach closings, disrupt commercial fishing operations
clogging nets, and close down coal-burning and nuclear power plants
by clogging their cooling water intakes
3. Tuna pens have been wiped out by swarms of jellyfish attracted the pens by
the fish feed and fish waste found there
4. Factors that play a role in this:
a. Overfishing of the species that can eat small jellyfish – the jellyfish in
turn then feed on fish eggs and larvae
b. Inputs of excessive plant nutrients from fertilizer runoff and sewage
due to coastal urban development
i. Spurs the growth of phytoplankton – jellyfish food
c. Warmer waters are also associated with jellyfish blooms
viii. Case Study: Sharks
1. Keystone species – some sharks play a crucial role in helping to keep their
ecosystem functioning
2. Without this ecosystem service provided by some shark species, the oceans
would be teeming with dead and dying fish and marine mammals
3. 73 million sharks are caught each year for their valuable fins and then
thrown back alive into the water, fins removed, to bleed to death or drown
because the can no longer swim.
4. Sharks are also killed for their livers, meat, hides, and jaws, and because we
fear them.
a. Each year an estimated 50 million sharks die when fishing lines and
nets trap them
5. Consuming shark fins and shark meat can be harmful to human health
because they contain very high levels of mercury and other toxins (AKA
Bioaccumulation)
6. Sharks are especially vulnerable to population declines because they grow
slowly, mature late, and have only a few offspring per generation
a. Among the earth’s most vulnerable and least protected animals
ix. Biological extinction – mostly from overfishing, water pollution, wetlands
destruction, and excessive removal of water from rivers and lakes
1. A combination of habitat loss, overfishing, pollution, and ocean acidification,
marine life is poised to enter a new period of mass extinction, which would
eventually affect the world’s terrestrial and marine ecosystem and thus the
world’s economies
a. Most threatened of all marine species are sea turtles
b. 11-2: How Can We Protect and Sustain Marine Biodiversity?
i. Protecting marine biodiversity is difficult for several reasons:
1. The human ecological footprint and the fishprint are expanding so rapidly
that it is difficult to monitor their impacts
2. Much of the damage to the oceans and other bodies of water is not visible to
most people
3. Many people incorrectly view the seas as an inexhaustible resource that can
absorb an almost infinite amount of waste and pollution and still produce all
the seafood we want.
ii.
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vii.
viii.
4. Most of the world’s ocean area lies outside the legal jurisdiction of any
country – classic case of tragedy of the commons
There are several ways to protect and sustain marine biodiversity:
1. Regulatory approach
a. 1975 Convention on International Trade in Endangered Species
(CITES)
b. 1979 Global Treaty on Migratory Species
c. US Marine Mammal Protection Act of 1972
d. US Endangered Species Act of 1973
e. US Whale Conservation and Protection Act of 1976
f. 1995 International Convention on Biological Diversity
i. The problem is with some international agreements, it is hard
to get all nations to comply – which can weaken the
effectiveness of such agreements
1. The resulting fines and punishments for violators are
often inadequate
2. Use economic incentives
a. According to the World Wildlife Fund study, sea turtles are worth
more to coastal communities alive than dead
Exclusive Economic Zone - Foreign fishing vessels can take certain quotas of fish
within such zones – but only with government permission
High Seas – open oceans beyond the legal jurisdiction of any country ---- law and
treaties pertaining to them are difficult to monitor and enforce
1. The United Nations Law of the Sea treaty, which went into effect in 1984
a. Not signed by the US
Marine Protected Areas (MPAs) – areas of ocean partially protected from human
activities
1. Only partially protected – nearly all allow dredging, trawler fishing, and
other ecologically harmful resource – extraction activities
Ecosystem Approach – widespread use – focused on protecting and sustaining
entire marine ecosystems and their ecosystem services for current and future
generations rather than relying mostly on protecting individual species
Marine Reserves – areas that are declared off limits to destructive human activates
in order to enable their ecosystems to flourish and recover
1. Would include large reserves on the high seas, especially near extremely
productive nutrient upwelling seas
2. Smaller reserves in coastal zones that are adjacent to well-managed,
sustainable commercial fishing areas
a. “Underwater wilderness” areas would be closed to activities such as
commercial fishing, dredging, and mining, as well as to waste disposal
3. Studies show that within fully protected marine reserves, within 2-4 years
after a strict protection begins, commercially valuable fish populations can
double, average fish size can grow by almost a third, fish reproduction can
triple, and species diversity can increase by almost one-fourth
Marine Hotspots – threatened areas in need of full protection because of their
importance to marine biodiversity and ecosystem services
1. Many marine reserves are too small to protect most of the species within
them and do not provide adequate protection against illegal fishing, garbage
dumping, or pollution that flows from the land into coastal waters
ix. Researchers are struggling to design ways to monitor changes over vast areas and
determine the effectiveness of such reserves in sustaining and rebuilding marine
populations
1. Urge that protected corridors be established to connect the global network of
marine reserves
x. Prevention Approach – toward aquatic ecosystem degradation, which is far less
expensive and risky than restoration efforts
1. New corals – divers drill holes into the dead reefs and insert ceramic discs
holding springs of fledgling coral
2. To deal with problems of pollution and overfishing:
a. Closely monitor and regulate fishing and coastal land development
and greatly reduce pollution from land-based activities
b. Chemicals that are put on lawns and the kinds of waste that are
generated need to be monitored because most of it will end up in the
ocean
c. Purchase only sustainably harvested or sustainably farmed seafood
xi. Integrated Coastal Management – a community-based effort to develop and use
coastal resources more sustainably
1. The overall aim of such programs is for fisheries, business owners,
developers, scientist, citizens, and politicians, to ID shared problems and
goals in their use of marine resources
c. 11-3: How Should We Manage and Sustain Marine Fisheries?
i. 1st step in protecting and sustaining the world’s marine fisheries is to make the best
possible estimates of their fish and shellfish populations
1. Maximum Sustainable Yield (MSY) – model to project the maximum number
of individuals that can be harvested annually from fish of shellfish stocks
without causing a population drop
2. Optimum Sustainable Yield (OSY) – have attempted to take into account
interactions among species and to provide more room for error
3. Multispecies Management – a number of interacting species, which takes into
account their competitive and predator-prey interactions
4. Precautionary Principal – sharply reducing fish harvest and closing some
overfished areas until they recover and until we have more information
about what levels of fishing they can sustain
ii. Obvious Steps –
1. Take in protecting marine biodiversity – and therefore fisheries – is to
regulate fishing
2. Catch-Share System – where each fisher gets a share of the total allowable
catch
3. Comanagement – which coastal communities and the government work
together to manage fisheries
a. Set quotas for various species and divides the quotas among
communities
b. May also limit fishing seasons and regulate the types of fishing gear
that can be used to harvest a particular species
iii. Government Subsidies:
1. Governments around the world give a total of more than $30 billions per
year in subsidies to fisheries to help them keep their business running
a. Each year $10 to $14 billion of these subsidies is spent to encourage
overfishing and expansion of the fishing industry
iv. Consumer Choices –
1. An important component of sustaining aquatic biodiversity and ecosystem
services is bottom-up pressure from consumers demanding sustainable
seafood, which will encourage more responsible fishing practices
2. Labeling fresh and frozen seafood to inform consumers about how and
where the fish and shellfish were caught
a. Certification of sustainably caught seafood
3. Certify and label products of sustainable aquaculture, or fish farming
operations
4. To choose plant-eating species of fish
a. Ex. Tilapia – raised through aquaculture
v. History shows that most attempts to improve environmental quality and promote
environmental sustainability require bottom-up political and economic pressure by
concerned citizens. INDIVIDUALS MATTER
d. 11-4: How Should We Protect and Sustain Wetlands?
i. Coastal wetlands and marshes and inland wetlands are important reservoirs of
aquatic biodiversity that provide vital economic and ecosystem services
ii. For centuries, people have drained, filled in, or covered swamps, marshes, and other
wetlands to create rice fields or other cropland, to accommodate expanding cities
and suburbs, and to build roads
1. Most of this will be underwater before the end of the century because of
rising sea levels
iii. In the US zoning laws have been used to steer development away from wetlands
1. Requires a federal permit to fill in wetlands occupying more than 1.2 hectare
(3.0 acres) or to deposit dredge material in wetlands
iv. Mitigation Banking – allows destruction of existing wetlands as long as an equal or
greater area of the same type of wetland is created or restored
1. At least half of the attempts to create new wetlands failed to replace lost
ones, and most of the created wetlands did not provide the ecosystem
services of natural wetlands
2. Projects often fail to meet the standards set for them and are not adequately
monitored
3. Should be used only as last resort
v. Private investment bankers make money by buying wetland areas and restoring or
upgrading them by working with the US Army Corps of Engineers and the US
Environmental Protection Agency
1. Banks or credits that the bankers can then sell to developers
vi. Most US wetland banking systems require replacing each hectare of destroyed
wetland with two or more hectares of restored or created wetland as a build-in
ecological insurance policy
vii. We need to make sure that new replacement wetlands are created and evaluated
BEFORE existing wetlands are destroyed.
1. This example of applying the precautionary principal is often the reverse of
what is actually done
viii. Case Study: Florida Everglades
1. South Florida’s Everglades – created as a vast network of wetlands with a
variety of wildlife habitats
2. 1947 the US government established Everglades National Park
a. But this protection effort did not work – as conservationists had
predicated – because of massive water distribution and land
development project to the north
3. The canal provided flood control by speeding the flow of water, but it drained
large wetlands north of Lake Okeechobee – which farmers then converted to
grazing land
4. Have provided south Florida’s rapidly growing population with a reliable
water supply and flood protection
a. Has been drained, paved over, polluted by agricultural runoff, and
invaded by a number of plant and animal species
5. 1970’s – that this huge plumbing project was reducing populations of native
plants and wildlife
6. 1990’s – Comprehensive Everglades Restoration Plan – several ambitious
goals
a. Restoration of the curving flow of more than half of the Kissimmee
River
b. Removal of 400km (248miles) of canals and levees that block natural
water flows from the south of Lake Okeechobee
c. Conversion of large areas of farmland to marshes
d. The creation of 18 large reservoirs and underground water storage
areas to store water for the lower Everglades and for south Florida’s
population
e. Building a canal-reservoir system for catching the water now flowing
out to sea and pumping it back into the Everglades
e. 11-5: How Should We Protect and Sustain Freshwater Lakes, Rivers, and Fisheries?
i. Currently, 4 of every 10 freshwater species in N. America are considered to be
vulnerable, threatened, or endangered, according to a joint study by US, Canadian,
and Mexican scientist
ii. Invasive species, pollution, and climate change threaten the ecosystems of many
lakes, rivers, and wetlands
iii. Increasing human populations pressure and projected climate change during this
century will elevate these threats
iv. Case Study: Great Lakes and Invasion by Alien Species
1. Invasions by nonnative species are a major threat to the biodiversity and
ecological functioning of many lakes
2. Collectively, the Great Lakes are the world’s largest body of freshwater
3. Many of the alien invaders arrive on the hulls of, or in bilge-water discharges
of, oceangoing ships that have been entering the Great Lakes through the St.
Lawrence Seaway since 1959
4. Trying to use a chemical that kills lamprey larvae – cost $15 million a year
v. Rivers and streams provide important ecosystem and economic services, but
overfishing, pollution, dams, and water withdrawal for irrigation are disrupting
these services
1. Services are given little to no monetary value when the cost and benefits of
dam and reservoir projects are assessed
2. Values to these ecosystem services – an application of the full-cost pricing
a. This would help to sustain them
vi. The Columbia River dam system has benefited many people, but it has sharply
reduced populations of wild salmon
1. Dams interrupt their life cycle by interfering with the migration of young fish
downstream, and blocking the return of mature fish attempting to swim
upstream to their spawning grounds
vii. Sustaining freshwater aquatic systems begins with understanding that land and
water are connected
1. Lakes and streams receive many of their nutrients from the ecosystem of
bordering land
viii. Protect a stream or lake from excessive inputs of nutrients and pollutants, we must
protect its watershed
1. Freshwater ecosystems can be protected through laws, economic incentives,
and restoration efforts
a. Ecosystem and economic services of rivers will probably require
taking down some dams and restoring river flows
2. 1968, the US Congress passed the National Wild and Scenic Rivers Act to
establish protection of rivers with outstanding wildlife, geological, scenic,
recreational, historical, or cultural values
a. Wild Rivers – those that are relatively inaccessible (except by trail)
b. Scenic Rivers – rivers of great scenic value that are free of dams,
mostly underdeveloped, and accessible in only a few places by roads
ix. Sustainable management of freshwater fisheries involves supporting populations of
commercial and sport fish species, preventing such species from being overfished,
and reducing or eliminating populations of harmful invasive species
1. Traditional way – to regulate the time and length of fishing seasons and the
number and size of fish that can be taken
2. Other techniques include building reservoirs and ponds and stocking them
with fish, and protecting and creating fish spawning sites
a. Hatcheries can be used to restock ponds, lakes, and streams
x. All of these practices should be based on continuing studies of their effects on
aquatic biodiversity and ecosystem services
f. 11-6: What Should be our Priorities for Sustaining Aquatic Biodiversity?
i. Proposed the following priorities for an ecosystem approach to sustaining aquatic
biodiversity and ecosystem services:
1. Complete the mapping of the world’s aquatic biodiversity
2. ID and preserve the world’s aquatic biodiversity hotspots
3. Create large and fully protected marine reserves
4. Protect and restore the world’s lakes and river systems
5. Initiate ecological restoration projects worldwide
6. Find ways to raise the incomes of people who live on or near protected lands
and waters
ii. These strategies for protecting the earth’s vital biodiversity and ecosystem services
will not be implemented without bottom-up political pressure on elected officials
from individual citizens groups
1. “Vote with wallets”
iii. We can eat lower on the food chain by choosing plant-eating species