Quizzes Flashcards
Estuary Definition:
body of water where a river meets the sea and where fresh and saltwater mix
4 categories of carbon sources:
Ocean sources
River sources
Emergent veg
Submergent veg
4 most abundant ions in salt water:
Cl-
Na+
Mg
SO4
General salinity range:
0.5-30 “BRACKISH”
Why does saltwater sink relative to freshwater
Saltwater is denser due to the salt concentration within the same volume of water
3 tidal cycles
Semi-Diurnal Tide: two almost equal high tides and two low tides each day
Diurnal Tide: only one high and one low tide each day
Mixed Tide: two uneven tides a day
What does Burrard Inlet have
Mixed
3 factors that influence tides in estuary
Amount of freshwater input
Tidal patterns and current
Geology of area
Climate
Winds and weather
Geology classes of estuary
Coastal plane/flooded river valley
Delta
Fjord
Tectonic
Bar-built
Lagoon
Stratification and Fresh-Seawater Circulation classes of estuary
Salt-wedge (most stratified (least mixed))
Fjord
Slightly stratified (deep estuaries)
Vertically mixed (most mixed, shallow estuaries)
Freshwater
What geologic class of estuary is associated with West Coast rivers
Flooded river valley
Howe Sound geologic class
Fjord
Based on the estuary stratification classification, () estuaries have the highest, degree of stratification, and () estuaries are the most well-mixed
salt-wedge, vertically-mixed
Stratification class with rapidly flowing river discharge into the ocean where tidal currents are relatively weak
Salt-wedge
Stratification class of geologically classified Fjord
Fjord
Factors that control Fjord stratification
Sill acts as a natural barrier for denser saltwater
Rank the species of Pacific salmon based on the time spent in the estuary as juveniles before moving offshore into the marine environment (in order of increasing time spent)
Pink
Chum
Chinook
What are the two dominant life-history strategies of Chinook?
Ocean type - move into the estuary sooner and spend an extended amount of time growing
Stream type - spend longer in the stream growing before going to the estuary
Which occupies the estuary longer?
Ocean
Two life functions carried out by juvenile Pacific salmon in estuary habitats?
Need to undergo physical transformations from freshwater to saltwater fish as juveniles
Need to undergo physical transformations from saltwater to freshwater fish as spawners
Consume prey and grow large enough to migrate to the ocean
Imprinting on their natal streams
(concentrations of the hormone thyroxine =facilitate olfactory imprinting)
What line(s) of evidence suggests that some juvenile Chinook salmon rely on estuary habitats for an extended period of time before migrating off-shore?
Chinook salmon were recorded using tidal channels - presence detected over time, increasing fork length and growth
Mark and recapture surveys saw juvenile chinook return to tidal channels over several tide cycles
The scientific name of eelgrass?
Zostera marina
The main way that eelgrass reproduces?
Reproduce asexually from rhizomes
Ecological Services and Functions of eelgrass
- carbon capture and storage (sequestration!)
- removal of polluting nutrients, compounds
- trapping of suspended sediment, thereby improving water clarity and enhancing eelgrass growth
- wave attenuation
- reduces nearshore erosion by anchoring sediment with its spreading rhizomes
- provides food, breeding areas, and protective nursery habitat for fish, shellfish, crustaceans and many other animals
Human Impacts on Eelgrass
Dredging and filling associated with the construction of harbours and ports
Excess nutrient loading and chemical contamination
Logging
Land development
Oil spills
Docks create shading problems for eelgrass beds
Anchoring of recreational boats along the nearshore disturbs rhizomes
Boat propellers cut eelgrass beds in shallow waters
Invasives - European green crab
Burrard Inlet, what are three (3) distinct types of major stressors that have contributed to eelgrass declines?
- Dredging/infilling
- Eutrophication/water quality/chemical contamination
- Logging, oil spills, docks, anchoring, boat propellors
Factors Influencing eelgrass restoration Success
Proximity to natural eelgrass bed
Site selection (substrate, depth, current or wave disturbance)
Quality of donor stock
Light
Salinity
Temperature
a practical and common metric used to determine if a restored eelgrass bed is approaching reference condition?
Shoot density (m2)
Canada Goose Scientific name?
Five sub-species found in BC:
B. c. canadensis – Atlantic
B. c. moffitti – Great Basin
B. c. leucoparia – Aleutian
B. c. occidentalis – Dusky
B. c. fulva - Vancouver
Breeding goose on Vancouver Island?
(no historical records of large nesting populations)
What law protects Canada geese AND what level of government is responsible for
management decisions related to Canada geese?
Migratory Birds Convention Act (1994) MBCA
Federal government – Canadian Wildlife Service (CWS) within Environment Canada
What are the four (4) politically-acceptable mechanisms for managing geese
populations in BC?
Hunting
Damage/Danger Permit
Addling (oil pricking similar… basically a means to sterilize eggs)
First Nations harvesting (Charity permit is a use for the meat, but not a management tool)
Exclosure fencing
What stage in the life cycle of Canada Geese are herbivory pressures on native
marsh vegetation greatest and why?
During molting from mid-June to mid-July as they concentrate in large groups and cannot fly, hence their local grazing pressure is most intense.
Second greatest time is when young birds are maturing as energy demands are high
(partial marks)
What characteristics of human-modified landscapes have contributed to explosive
population growth of Canada geese?
Geese have 3 basic habitat requirements: Water, open space, and food.
Human-modified landscapes include the conversion of forests to an abundance of
open, green space in the form of agricultural land, parks, golf courses and other
features that support geese populations.
Across our urban landscape, we have also nearly eliminated hunting
opportunities, therefore there is no natural predator
