Flashcards in Aquatic Ecology final Deck (324)
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61
larger scale effects of harvesting fish feed
taking ~85% of sea predators food; seabirds, marine mammals
62
Effects of farming on wild salmon health
smolts travelling to ocean pass by fish farms, pick up significant infections rates; many farm fish have sea lice (infestation from low diversity, close quarters)
63
forage fish
prey fish/bait fish, small pelagic fish preyed on by larger predators for food
64
areas of application for stable isotopes
paleoclimate reconstruction (O2)
paleolimnology
terrestrial aquatic linkages
food web ecology
migratory studies
individual feeding behaviour
65
paleolimnology, stable isotopes
historic patterns of productivity, mostly C, N
66
terrestrial aquatic linkages, stable isotopes
terrestrial--> aquatic (lake management)
marine derived nutrients (salmon)--> terrestrial
67
food web ecology, stable isotopes
contaminant transfer, ecology
68
migratory studies, stable isotopes
birds, fish, zooplankton, mammals, C
how much time in open/coastal ocean
algae isotope ratio highly variable in open/coastal
69
individual feeding behaviour, stable isotope
niche shift, omnivore, trophic position
within single population
ex. stickleback - some neutral all the time, some pelagic all the time, all related to evolution, studiable by isotopes
70
∂13C ratios
C fractionates during photosynthesis, little-no fractionation up food chain
determine what food sources are based on ∂13C ratio
71
∂13C determination of food source possible with following conditions
large isotopic separation (btw food sources)
over time food signatures are stable
two/few food sources
72
examples of ∂13C determination of food source
middle of lake - very highly negative
close to littoral zone (terrestrial C) - less negative
73
∂15N in food web ecology
tells trophic level, fractionated throughout trophic levels
74
trophic enrichment of ∂15N
2.92+/- 0.8 ‰
75
typical ∂15N signatures
algae 4-8‰
invertebrates 8-16‰
forage fish 10-14‰
predatory fish 10-18‰
76
typical ∂13C signatures
off-shore -28‰ (depleted)
near-shore -14‰
77
why is ∂15N fractionated up trophic level
preferential excretion of 14N
78
high ∂15N
heavy
more positive
79
atmospheric N2 ∂15N
0‰
hasn't been fractionated by organisms
80
enriched in ∂13C
heavy
less negative
∂13C never positive
81
depleted in ∂13C
light
more negative
∂13C never positive
82
inorganic fertilizer ∂15N
0‰
made from captured atmospheric N
83
fractionation
in a chemical reaction one isotope proceeds at a quicker rate than the other due to a slight difference in mass (lighter synthesized faster/easier, more efficient)
84
two types of fractionation
animals- body tissue
algae
85
animal tissue fractionation
14N is preferentially released so 15N increases relative to its food source
86
algae fractionation
photosynthetic enzyme can process 12C molecules quicker than 13C, utilize it preferentially
based on size
87
algae photosynthetic enzyme that processes carbon molecule
RUBISCO
88
isotopic composition in foodweb
sediment: ~-30, towards terrestrial
inverts: ~-33, ~50/50 terrestrial/planktonic
piscivorous fish: ~-28/-30 pretty close to terrestrial
89
littoral zone
near shore area where sunlight penetrates all the way to the sediment and allows aquatic plants (macrophytes) to grow
90
