Aquatic Biodiversity

Aquatic Biodiversity
What are the major types of saltwater
life zones, and how do human activities
affect them?
What are the major types of freshwater
life zones, and how do human activities
affect them?
Aquatic Life Zones (Aquatic Biomes)
• Characterized by amount of ______
dissolved in the water.
• Saltwater (marine) and freshwater
cover ~ _____ % of the earth’s
surface.
Aquatic Life Zones (Aquatic Biomes)
• Characterized by amount of NaCl
dissolved in the water.
• Saltwater (marine) and freshwater
cover ~ 75% of the earth’s surface.
• Food chains and webs are more
complex and longer than terrestrial
ones.
AQUATIC ENVIRONMENTS
 Organisms & Aquatic Life Zones
1. Plankton: free floating, weakly swimmers
- Phytoplankton (autotroph): ex: algae
- Zooplankton (heterotroph): animal plankton.
- Microscopic: ex: protozoans (amoeba, paramecia)
and macroscopic: jellyfish, krill, sunfish
-Ultraplankton: autotrophic bacteria (cyanobacteria
2. Nekton: free-swimming. ex: fish, turtles, whales
3. Benthos: bottom dwellers. Ex: barnacles, lobsters, crabs
4. Decomposers: ex: bacteria, water molds
Life as a Plankton
Limiting Factors in Aquatic Life
Zones
Name a few limiting factors:

______________________

_____________________

_____________________
Limiting Factors in Aquatic Life
Zones
Life (numbers and diversity) in the surface, middle, and
bottom layers are determined by:
Temperature
Sunlight penetration (for photosynthesis):affected by
depth and turbidity of water
Amount of dissolved oxygen:  at lower levels
Nutrient availability (CO2, NO3-, PO43-):
shallow waters lots of nutrients
Open ocean-  nutrients
Bottom of the ocean:  nutrients
 Oceans
• High biodiversity
• 2 zones:
1. Coastal- warm and nutrient rich area
90% of all marine species!  level of
photosynthesis
2. Open sea- cooler and less species
3. Ocean Bottom
The Coastal Zone
The Coastal Zone
The Coastal Zone: ??
The Coastal Zone: Estuaries
Coastal Zone: Estuaries
• Enclosed body of water formed where
seawater mixes with freshwater from
rivers & streams.
• Called “ Marine nurseries”- habitats for many
juvenile fish species.
• Warm, rich in nutrients, lots of light: 
NPP
• Estuaries and coastal wetlands include inlets,
mangrove forest swamps, & salt marshes
 Estuaries
• Extremely fertile because the river brings lots
of sediments.
• Stressful conditions and abundant nutrients
result in low species diversity, but great
abundance of the species present.
(What is another way to say this?)
Estuaries and Coastal Wetlands:
Centers of Productivity
1) Give 2 reasons why estuaries and
coastal ecosystems have high levels
of biodiversity.
Estuaries and Coastal Wetlands:
Centers of Productivity
Estuaries:
Filter toxic pollutants, excess plant nutrients,
sediments, and other pollutants.
Reduce storm damage by absorbing waves
and storing excess water produced by storms
and tsunamis.
Provide food, habitats and nursery sites for
many aquatic species.
It has a  level of photosynthesis due to 
light +  nutrients which supports biodiversity.
Herring gulls Peregrine falcon

Snowy
Egret Cordgrass

Short-billed
Dowitcher

Marsh
Periwinkle
Phytoplankton

Smelt

Zooplankton and
small crustaceans
Soft-shelled
clam

Clamworm
Bacteria

Producer to Primary to Secondary to All consumers

primary secondary higher-level and producers
consumer consumer consumer to decomposers
Type of Estuary: Mangrove
Forests
Mangrove
forests occur
in tropical
regions, while
salt marshes
occur in
temperate
regions.
Intertidal Zone
 Intertidal Zone
• Name 2 adaptations that allow
organisms to live in intertidal
environments.
____________, ____________
• Give examples of organisms that live in
this type of coastal area.
____________, ____________
 Intertidal Zone
• The area between high tides and low tides.
• Organisms have some adaptation to
withstand wave activity. Ex: burrowing in
sand, attaching to rocks, hiding in
shells.
• Rocky shores- areas pounded by waves,
varieties of algae, snails, crabs, etc.
• Sandy shores- no plants or algae, but insects,
shorebirds, crabs, and worms found.
 Coral Reefs
• Structure that is formed by coral polyps
(small invertebrates that live in colonies).
• Typically found in warm coastal waters of the
tropics and subtropics.
• Coral polyps form a hard, stony, exoskeleton
made of limestone.
• SYMBIOSIS: between polyps (animals) and
algae (protists).
 Coral Reefs Climate
• Usually found near land in shallow (lots
of light), warm, salty water.
• Tropical regions.
 Importance of Coral Reefs
• High biodiversity- considered the most
diverse and productive
• Grow very slowly
• Complex relationships that exist between
many organisms.
Sample Food Chain
Example of Food Chain
S ta rfis h

Cora l
Octopus

Zoopla nkton

Mora y Ee l
P hytopla nkton
 Damage to Coral Reefs
• Very sensitive to environmental changes.
• Natural disturbances: hurricanes or typhoons,
and predation by a large starfish-Acanthaster
• Anthropogenic disturbances (human)-
sediment run off, pollution, reef fishing,
coral bleaching…
• 300+ reefs are protected as reserves or
parks.
 Freshwater Life Zones
• Cover less than 1% of earth’s surface.
• Low salt concentration- < 1%
• Types:
Flowing (lotic) - streams, and rivers
Standing (lentic) - ponds, lakes, inland
wetlands
Lakes Zones
 Lakes Zones
• divided into four different “zones” determined by
depth and distance from the shoreline:
1. Littoral zone- top layer, shallow/near shore, 
biodiversity. aquatic plants, grazing snails, clams, insects,
crustaceans, fishes, and amphibians
2. Limnetic zone-sunlit water surface layer, main
photosynthetic layer. plankton, fishes
3. Profundal zone-cool and dark layer,  O2
4. Benthic zone-bottom layer, decomposers and
detritivores.
Freshwater Life Zones
Standing water Flowing water

Fig. 7-16 p. 139

 Lake Classification
Classified by: nutrient content and primary
productivity
Oligotrophic Eutrophic
Newly formed Excess supply of nutrients
Poorly nourished (Phosphates & nitrates)
Little sediment Shallow water
Deep water Murky water color
Clear water color High net prod.
Low net primary prod. Lots of plants, fish,
Trout, smallmouth bass plankton

MESOTROPHIC LAKES- intermediate

between oligotrophic and eutrophic
Effects of Plant Nutrients on
Lakes:
Too Much of a Good Thing

Plant nutrients from a lake’s environment

affect the types and numbers of organisms it
can support.
Effects of Plant Nutrients on
Lakes:
Too Much of a Good Thing

Cultural eutrophication:
Human inputs of nutrients from the
atmosphere and urban and agricultural
areas can accelerate the eutrophication
process.
* Not part of the Ch. 52 Quiz
 Terminology
Surface water- precipitation that does not
sink into ground or evaporate
Runoff- surface water that flows into
streams
Watershed (Drainage basin)- The region
draining into a river, river system, or other
body of water.
Not part of the Ch. 52 Quiz
Characteristics of Rivers and Streams
• bodies of flowing water moving in one direction
• found everywhere—they get their start at
headwaters, which may be springs, snowmelt
or even lakes
• travel all the way to their mouths, usually
another water channel or the ocean
• Not part of the Ch. 52 Quiz
Freshwater Inland Wetlands:
Vital Sponges
Inland wetlands
act like natural
sponges that
absorb and store
excess water
from storms and
provide a variety
of wildlife
habitats.
 Freshwater Inland Wetlands
• Lands that are covered with fresh water year round
or seasonally and located away from coastal areas.
• High biodiversity
• Ex: Marshes, Swamps, Floodplains, and Artic tundra
(summers)
• Vary in size- small to large
• Important in filtering pollutants, absorbing excess
water from storms, & providing habitats
• Not part of the Ch. 52 Quiz
Impacts of Human Activities on
Freshwater Systems
Dams, cities, farmlands, and filled-in wetlands alter
and degrade freshwater habitats.
Dams, diversions and canals have fragmented about 40%
of the world’s 237 large rivers.
Flood control levees and dikes alter and destroy aquatic
habitats.
Cities and farmlands add pollutants and excess plant
nutrients to streams and rivers.
Many inland wetlands have been drained or filled for
agriculture or (sub)urban development.
Not part of the Ch. 52 Quiz