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Marine Biology
• “Let’s name the zone.. The zones…
• http://www.youtube.com/watch?v=ufxGw8
EqY5Q&safe=active
Major Ocean Life Zones
Intertidal
• Intertidal Zone:
– The area of shoreline between the low and high
tides
– Stressful, biologically productive habitat
– Sandy beaches:
• Constantly shifting environment, little protection against
waves
– Rocky shores:
• Good anchorage for seaweeds and animals, but
exposure to wave action at high tides; temperature
fluctuations and drying out at low tides
• Inhabitants have adaptations to drying out
Intertidal
Benthic
• The Benthic Environment
– The ocean floor, which extends from the
intertidal zone to the deep ocean trenches
– Consists of sediments (sand and mud)
– Burrowing animals
• Bacteria, worms, clams, etc.
– Three zones:
• Bathyal (shallowest)
• Abyssal
• Hadal (deepest)
Major Ocean Life Zones
Coral Reefs
• Benthic Environment:
– Corals: soft-bodied animals, similar to jellyfish
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Live in hard cups or shells of calcium carbonate
Accumulated skeletons produce coral reefs
Found in warm, shallow waters
Require light for symbiotic zooxanthellae
Also capture food with stinging tentacles
High productivity even in poor nutrient waters
Most diverse marine environment - 100s of species
Ecologically important as habitat and protect coastlines
form erosion
• Provide humans with foods, pharmaceuticals, recreation
Coral Reefs
Coral Reefs
Sea Grass Beds
• Benthic Environment
– Sea Grasses
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Flowering plants adapted to live in sea water
Require shallow water for photosynthesis
Quiet temperate, subtropical, and tropical waters
High primary productivity
Ecologically important:
– Stabilize sediments, reduce erosion, provide food and
habitat for marine organisms
Sea Grass Beds
Kelp Forests
• Benthic Environment
– Kelps
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Largest and most complex of all seaweeds
Brown algae,
Common in cooler temperate marine waters
Especially abundant in relatively shallow waters
along rocky shores
• Primary food producers for kelp forest ecosystem
• Provide habitat for many marine organisms:
– Tubeworms, sponges, sea cucumbers, clams, crabs,
fishes, sea otters
• Very diverse ecosystem
Kelp Forests
Problems in the Kelp Forests
• Otters in Trouble
– Sea urchins feed on kelp  otters feed on sea
urchins  kelp is maintained
– Sea otter population in Alaska has had a 90%
decline since 1990
• Sea urchin populations are exploding, devastating kelp
forests
• Killer whales typically feed on seals and sea lions, but
those populations have declined, so now feed on otters
• Starting point is possibly decline in fish stocks caused by
overfishing/climate change
• Terrestrial food chains have also been affected
Sea Otters- Keystone Species
Neritic Province
• The Neritic Province
– Part of the pelagic environment that overlies the
ocean floor from the shoreline to a depth of 200
meters
– Organisms are floaters (plankton) or swimmers
(nekton)
– Euphotic Zone: upper level of neritic zone
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Sufficient light to support photosynthetic organisms
Phytoplankton are basis of food webs
Zooplankton feed on phytoplankton
Plankton-eating nekton consumes zooplankton
Carnivorous nekton consumes plankton-eating nekton
Floaters and Swimmers
Oceanic Province
• The Oceanic Province
– The part of the pelagic environment that overlies
the ocean floor at depths greater than 200 m
– Largest marine environment (75% of water)
– Loosely described as ‘deep sea’
– Cold waters, high pressure, no light
– Life adapted to darkness and scarce food
• Drifting or slow swimming, reduced bone & muscle mass
• Light producing organs to locate mates or prey
• Depend on ‘marine snow’ (organic debris form upper
layers of ocean)
• Filter feeders, scavengers, predators
• Many large invertebrates, e.g., giant squid
Deep Sea Life
Global Climate Change
1. What are the four main life zones in the
ocean, and how do they differ from one
another?
2. Finish Deep Sea Planet Earth
Day 3
Case Study:
Depleting Bluefin Tuna Stocks
– Being fished at 4 times the sustainable level
– Economic value places it in danger
– Conservation measures protect the species
– Overfishing
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Harvesting of fishes faster than they can reproduce
30% of worldwide fishes
80% of commercial fish stocks in US
If overfishing and pollution aren’t curbed,
populations of all harvested seafood species will
be gone by 2048
Human Impacts on the Ocean
• Learning Objectives:
1. Contrast fishing and aquaculture and relate
the environmental challenges of each
activity
2. Identify the human activities that contribute
to marine pollution and describe their effects
3. Explain how global climate change could
potentially alter the ocean conveyor belt
Human Impacts on the Ocean
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Fisheries and aquaculture
Marine shipping
Marine pollution
Coastal development
Offshore mining
Global climate change
In 2008, less than 4% of ocean remained
unaffected by human activities; 41%
serious harm
Human Impacts on the Ocean
• Marine Pollution and Deteriorating Habitat
– Paradox: ocean provides food but is used as
dumping ground
– Pollution increasingly threatens fisheries
– 80% of ocean pollution comes from land
activities
Human Impacts on the Ocean
Human Impacts on the Ocean
Human Impacts on the Ocean
• World Fisheries
– Valuable food resources
• 90% of world’s catch is fishes,
• 6% is clams, oysters, squid, octopus, and other
molluscs
• 3% is crustaceans: lobsters, crabs, shrimp
• 1% is marine algae
– World’s Annual Harvest
• 1950 - 19 million tons
• 2004 - 95 million tons
Human Impacts on the Ocean
• Problems and Challenges for the Fishing Industry
– No nation has legal claim to open ocean
• Resources are susceptible to overuse and degradation
(Tragedy of the Commons)
– Many species have been harvested to the point
where their numbers are severely depleted
• Unstable for marine species that rely on them as part of food
web
• At least 75% of world’s fish stocks are exploited,
overexploited or depleted
– Growing human population requires protein
– Technological advances allows efficient catch, removing
all fish from an area
– 25% of all is bycatch (unintentionally caught, then
discarded)
What a Scientist Sees
Human Impacts on the Ocean
• Aquaculture
– Fish farming: growing of aquatic organisms for human
consumption
• Fresh and marine water
• HDCs harvest more from open ocean
• Developing nations harvest more from aquaculture
– Abundant supply of cheap labor
– Limit to harvest is the area available for farming
• Fish farms have dense populations
– Lots of polluting waste
– Cause net loss of wild fish (raised fish tend to be carnivorous)
– Ocean ranching: deep-water, off-shore aquaculture
• Doesn’t harm coastline, but less oversight
Human Impacts on the Ocean
Human Impacts on the Ocean
• Shipping, Ocean Dumping, Plastic Debris
– Millions of ships dump oily ballast and waste
– MARPOL bans marine pollution from shipping
industry
• Not well enforced
– Ocean Dumping Ban Act
• Cities used to dump sewage into ocean, diseasecausing organisms contaminated shellfish
– Plastic waste
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Doesn’t degrade, just breaks up into smaller pieces
Pacific Garbage Patch, 2009, 2x size of Texas
Plastic pieces entangle marine mammals and birds
Filter feeders ingest plastic pieces, carriers of PCBs
Human Impacts on the Ocean
Human Impacts on the Ocean
• Coastal Development
– Alters or destroys coastal ecosystems:
• Mangroves, salt marshes, sea grass beds, coral
reefs
– Coastal areas overdeveloped, highly polluted,
overfished
– Coastal management plans are inadequate
• Biggest problem is human population size
• 60% of world’s population lives within150 km
(93 mi) of coastline
• As much as 75%, by 2025
Human Impacts on the Ocean
• Human Impacts on Coral Reefs
– 25% of world’s corals are at high risk
• Silt washing downstream from clear-cut forests is
smothering reefs
• High salinity from freshwater diversion projects
• Overfishing of top predators
• Damage by tourists
• Pollution from ocean dumping and coastal
pollution
• Bleaching = stressed corals expel zooxanthellae
What a Scientist Sees
Human Impacts on the Ocean
• Offshore Extraction of Mineral and Energy
Resources
– Large deposits of minerals lie under the sea
floor
• Manganese nodules – mining would adversely affect sea life and market value
would not cover expense of mining
– Disputes over deposits under international waters
• Petroleum – Major source of energy
– Major threat to fishing
Human Impacts on the Ocean
Human Impacts on the Ocean
• Climate Change
– Incomplete understanding, unanticipated
effects
• There could be a disruption of the ocean conveyor
belt, which transports heat around the globe
• Climate warming could shut down conveyor belt
within a decade
– Could cause major cooling in Europe
– Major warming in other parts of the world
– Would not sequester CO2 into ocean  more CO2 in
atmosphere  more warming  more weakening of belt
Global Climate Change
1. What are some of the harmful environmental
effects associated with the fishing industry?
With aquaculture?
2. How does the widespread use of plastics
contribute to ocean pollution?
3. How might the effect of global climate
change on the ocean alter the global
climate?
Addressing Ocean Problems
• Learning Objectives:
1. Describe international initiatives that address
problems in the global ocean
2. Explain goals associated with correcting
ocean problems in the future
Addressing Ocean Problems
• Problems are complex and require complex
solutions
– UN Convention on the Law of the Sea (UNCLOS) 1994 - 157 countries have ratified
• Protecting ocean resources
– UN fish stocks agreement - 1995
• Regulates marine fishing
– Fishery Conservation and Management Act - 1977
• Protect essential fish habitat for 600 species
• Reduce overfishing, rebuild populations, minimize bycatch
• Fishing quotas, restrictions on fishing gear, limits on number
of fishing boats, closure of fisheries during spawning
Addressing Ocean Problems
• Future Actions
– US Commission on Ocean Policy-2004 report
• Create a new ocean policy to improve decision
making– Consolidate agencies
• Strengthen science and generate information for
decision makers
– Need for high quality research
• Enhance ocean education to instill in citizens a
stewardship ethic
– Environmental education should be part of the curriculum
at all levels, including strong marine component
Addressing Ocean Problems
• Future Actions
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Establishment of “no-take” reserves
Substantial reduction of fishing fleet
Remove subsidies of fishing industry
Adopt an ecosystem-based approach to manage
ocean environments
• Focus on preserving the health and function of the
entire marine ecosystem
• Establish networks of fully protected marine reserves
• Less than 5% of US marine environments have been
protected, with great success
Addressing Ocean Problems
Case Study
• The Dead Zone in the Gulf of Mexico
– N and P runoff from Mississippi river
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Algae grow rapidly, dead algae sink to bottom
and decompose, deplete water of O2 (hypoxic
zone)
– Only anaerobic bacteria thrive there
– March to September, worst June-August
– Climate change is making dead zones
worse, even without runoff
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Threaten biodiversity and coastal fisheries
Case Study
Global Climate Change
1. Which international treaties aim to protect
ocean resources?
2. What are the main goals recommended by
the US Comission on Ocean Policy?
Major Ocean Life Zones
• Marine environment is divided into zones:
– Intertidal zone
– Benthic (ocean floor) zone
– Pelagic (ocean environment) zone
• Neritic
– From shore to 200 m (650ft) depth
• Oceanic
– Depth greater than 200m, beyond continental shelf
Quick Pop Quiz- just 2 and 4.
1. Describe the El Nino event and what
effect it has on global weather.
2. Name two zones in the ocean.
3. Describe what the TAO/TRITON array do.
4. Where are most coral reefs located?
(Think latitude.)