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Test 5

Terms in this set (41)

Estuary
Semi enclosed area where fresh water and seawater meet and mix
Support high abundances and diversity.
Many invertebrates as well as vertebrate species Grasses, oysters reefs , etc. provide refuge
from some predators.
Essential nursery habitat -for invertebrate
larvae and juveniles, as well as juvenile fish.
What are the psycho-chemical characteristics of estuaries?
- variable salinity: tidal and seasonal
- Variable temperatures: seasonal, diurnal, etc.
- Different sediment characteristics
** % sands and % silt-clays
- Variable turbidity and light levels
- Variable DO and pH
Stenohaline
Tolerate only narrow range of salinities
- limited to upper or lower ends of estuary and rarely penetrate into estuary proper
- marine or fresh water
ex.) echinoderms
Euryhaline
Organisms that tolerate wide range of salinity
- most estuarine organisms
Osmoconformers
Soft bodied estuarine animals, like molluscs and polychaete worms often maintain osmotic balance simply by allowing body fluids to change with salinity of water
- salinity of blood exactly matches water
Osmoregulators
Keep salt concentration of their body fluids more or less constant regardless of water salinity
- adapt to different salinities by regulating concentration of solutes in their body fluids
- blood salinity stays the same no matter what water salinity is
CONSTANT SALINITY IN BLOOD
**many fishes, crabs, molluscs, and polychaetes
** freshwater eel, chinook salmon
What happens when salinity of water becomes lower than that of blood in osmoregulators?
Get rid of excess water through active transport, absorb some solutes before surrounding water to compensate for those lost in elimination of water (gills and kidneys accomplish this)
Isosmotic
same osmotic pressure
Hyperosmotic
Having an osmolality greater than another fluid, ordinarily assumed to be plasma or extracellular fluid.
- concentration is greater
Hypoosmotic
solution that has a lower solute concentration than another solution
Marsh grasses (e.g. Spartina)
Cordgrasses
- land plants that tolerate salt
- do not tolerate total submergence by sea water
- high primary production and provide habitat and breeding grounds for many species, protect against erosion, and natural water purification systems
- found in estuaries
Mangroves (e.g. Rhizophora)
trees and shrubs adapted to live along tropical and subtropical shores around the worlds
- land plants that tolerate salt
** Rhizophora --> red mangroves
Anadromous fish
spawn in fresh water, and then return to the sea
- spend most of their lives at sea
- Ex. Salmon, Atlantic sturgeons
Semi-anadromous fish
spawn near fresh water/salt water interface
Ex. shortnose sturgeon
Catadromous fish
migratory pattern opposite of salmon
- breed at sea and migrate into rivers to grow and mature
** fresh water eel
Elevins
After hatching carry yolk sac
Fry
young salmon, after alevins
- spend a year or more in their home stream in the case of some species, feeding on insects and other tiny animals
- swim up to the surface, gulp air to fill their swim bladders, and begin to feed.
Smolts/smoltification
series of physiological changes where juvenile salmonid fish adapt from living in fresh water to living in seawater. Physiological changes during smoltification include altered body shape, increased skin reflectance
Identify the different salinity regimes where stenohaline vs euryhaline organisms would be found and give some examples of animals that are found in each
Stenohaline: 30-40% salinity
** only upper or lower ends of salinity, rarely penetrate into estuary
**echinoderms, goldfish, haddock

Euryhaline: 0-40% salinity
** wide range of salinity
** Blue Crab, Bullsharks, spartina (salt marshes and sea grasss), salmon, oysters and mussels
Are fish osmoconformers or osmoregulators? What is the approximate salinity of fish blood?
Osmoregulators
- keep salt concentration of their body fluids more or less constant regardless of water salinity
- adapt to different salinities by regulating concentration of solutes in their body fluids

** 10 is salinity
- less salty than sea water
How do fish osmoregulate?
- use organs and ions to adjust to water
- active transport of solutes by kidneys and gulls
** absorb some solutes from surrounding water to compensate for those lose in elimination of water
Are the following invertebrates osmoconformers or osmoregulators:

Oysters Crabs Polycheates Echinoderms
Osmoconformers: Oysters, mussels, polychaete worms, crabs, echinoderms

OsmoregulatorsL some crabs, some polycheates (most are conformers)
Which would require more energy - to osmoregulate or osmoconform?
Osmoregulators
Diagram the salinity conditions of an estuarine system along a tidal river to the intersection with open ocean. Describe how tide levels (e.g. low vs high tides) affect the salinity regimes. Describe how weather conditions can affect the salinity regimes.
(0%) Freshwater --> 35% Sea
- at high tides crab is covered by water with a salinity 35%
- low tide it is covered with a low salinity between 5%-15%

** Sea water flows in fresh water flows out since it is less dense
** seasonal variations in fresh water runoff from rivers as a result of rainfall patterns or snowmelt
** Coriolis effect
- North of the Equator, fresh water flows from rivers toward the sea is deflected toward the right
- south of equator , flow is left
** regions of little fresh water runoff and high evaporation. salinity of water increases
Briefly describe the global distribution of salt marsh and mangrove ecosystems. What are some of the important ecological services of salt marshes and mangroves?
Salt marsh:
- estuaries in temperate and subartic regions are usually bordered by this (extensive grassy areas that extend inland from mudflats)
- home to decay bacteria, diatoms and thick mats of green algae and cyanobacteria that play crucial role of decomposing plant material
- habitat for burrowing animals, crustaceans, nematodes, crabs
** shelter and food to many marine and land animals

Mangroves:
- found in tropical and subtropical region where they replace temperate salt marshes
- flowering land plants adapted to live in intertidal
- require freshwater
- shelter animals like crabs, and provide food, nurseries for shrimp, lobsters and fishes
- birds make home on branches, bees and bats feed on pollen , and insects feed on flowers and leaves
-Rhizophora
-aerial roots and pneumatophores help tolerate anoxic sediments
Describe the importance of mangrove roots to mangrove communities. What are some common aquatic animals that are part of these communities?
many organisms attach to or take shelter among submerged roots
- cyanobacteria, seaweeds, sponges, polychaetes. gastropods, oysters, barnacles
- sponges living on roots provide nitrogen compounds to plants and protecting them from organisms that damage roots like isopods
What are the ecosystem services of salt marshes and mangroves?
Filtration of pollutants
Trap sediments
Buffer against storms
Wildlife habitat (aquatic & terrestrial)
Nursery habitat (for numerous species
of fish and shellfish )
What are some common Estuarine Crustaceans?
Copepods, Shrimp, Crabs, Barnacles
What are some characteristics of Estuaries?
Support high abundances and diversity
. Many invertebrates as well as vertebrate species Grasses, oysters reefs , etc. provide refuge
from some predators.
Essential nursery habitat -for invertebrate
larvae and juveniles, as well as juvenile fish.
If you sampled the fish in an estuary, and identified and measured everything you caught, what would be your expectations with regard to ages of the fish.
If the fish in the estuary are juveniles then they are anadromous like salmon, smelts and shad
- very few spend entire life in estuaries
Identify the major stages of blue crab life history with regard to their distribution in estuaries.
1. Adult crab is in river
2. Females migrate with eggs to estuaries
3. Larvae is released in open ocean
4. Zoea (larvae crab) in high salinity
5. develop into Megalopoda (second stage)
6. Develop into young crabs and migrate to estuaries
7. Adult Crab is back in river
Anadromous vs semi- anadromous
Anadromous Life History
spawn in fresh water, and then return to the sea Ex. Salmon, Atlantic sturgeons

Semi-anadromous Life History
spawn near fresh water/salt water interface Ex. shortnose sturgeon
A common development practice up until about the mid-20th century was to fill in saltmarsh habitats and some areas of tidal rivers so that houses and business could be build closer to deep oceanic water. How would these development approaches affect blue crab fisheries?
Salt marshes provide habitat for blue crabs, will decline population of blue crabs
Describe the life history of salmon,
** most are anadromous fish, meaning they are born in freshwater (rivers or streams), travel to and live much of their lives in salt water and return to freshwater to spawn. After spawning, all Pacific salmon and up to 50% of other species die within a few weeks.

Salmon spend most of their adult life in North Pacific, after several years at sea salmon mature sexually and start migrating into rivers
- guided by earths magnetic field
- store fat once enter fresh water, kidneys must adjust to change from salt to fresh water
- eventually find exact stream of their birth
Identify different stages of salmon, what they are eating and where they are located
1. Salmon eggs
2. Alevins
3. Fry
4. Smolts
5. Swim from the rivers to the sea where they feed and mature
6. Return migration to rivers to spawn
7. Spawning
8. Dead salmon after spawning

** young salmon eat insects, invertebrates and plankton; adults eat other fish, squid, eels, and shrimp. Unlike all other salmon, the sockeye salmon has a diet that consists almost entirely of plankton.
Name some pacific salmon species
Chinook ( King ) Salmon
Coho ( Silver ) Salmon
Sockeye ( Red ) Salmon
Chum ( Dog ) Salmon
Pink ( Humpy ) Salmon
Steelhead Trout
Where do salmon go to spawn? Do all salmon die after spawning?
- Spawn in freshwater
- No some species like the steel head and rainbow trout can spawn many times before dying
Atlantic:
- breeds on both sides of North Atlantic and migrates across the ocean.
- sometimes survive after spawning and return to ocean
Pacific:
- die after spawning
What are the major mechanisms for osmoregulation in fish? Why is osmoregulation so important for salmon and other anadromous fish. What life stage is especially critical with regard to osmoregulation and why?
When salinity of water becomes lower than blood, they get rid of excess water via active transport, absorbing some solutes from surrounding water to compensate for lost in elimination of water through gills, kidneys and other structures
- important because they migrate back and forth between rivers and sea and still need to maintain stable internal environment
- When returning to rivers to spawn
A common development practice up until about the mid-late 20th century was the creation of dams on major rivers, typically for generating hydro-electric power as well as cooling mechanisms for coal and nuclear power plants. How would these development approaches affect salmon fisheries?
To restore and improve salmon fisheries, some of the older smaller dams are being removed and restoration programs are being used to restore the rivers and streams. How is this likely to help the salmon fishery?
- Dams block passages of salmon when attempting to migrate to rivers when spawning
- Create resevoirs
** Reservoirs also slow the flow of water and, through insolation, can cause its temperature to rise to levels that are lethal to salmon

- will allow salmons to pass to rivers to allow spawning, repopulation
Describe the life history of eels, especially American and European eels.
Catadromous
- breed at sea and migrate into rivers to grow and mature
- both american and european eels spawn in sargasso sea at depths of 400-700m
** spawn at different overlapping periods and locations in sea
** eggs hatch into tiny transparant larva and gradually develop into leaf shaped leptocephalus larvae
- American larvae drift in plankton for at least a year, juveniles move into rivers along atlantic
- european larvae spend at least two or three years drifting gulf stream to reach rivers through western europe
- adults of both species grow to more than 1 m in length
- believe to use earths magnetic field to navigate
These species are harvested for food and are also very important models for research. What is the genus?
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