Quiz 1 Flashcards
what is a Reynolds number tell
relative importance of viscous and inertial forces
what is the Reynolds number proportional to
body size and velocity
is water viscous or non-viscous
viscous (sticky)
what implications does water density have on organisms
less need for structural elements (ex jelly fish)
organisms differ less in density, thuscan float more easily
does water have a high or low specific heat
high specific heat (energy needed to change temperature)
how does water affect temperature of ecosystem
buffers temperature change
how does water affect light
it attenuates (diminishes) it
what makes water tea coloured
dissolving organic matter
what are the hypotheses for the differences between aquatic and terrestrial ecosystems
Aquatic habitats are depositional ecosystems – since water flows downhill so lots of detritus
> Nutrient limitation – aquatic systems are generally limited by phosphorus, while terrestrial
ecosystems are generally limited by nitrogen
> aquatic plants are smaller – more edible, more nutrient rich than terrestrial systems, more turnover
> strength of herbivory – herbivores consume 3x greater proportion of primary production in aquatic than terrestrial food webs
> trophic cascades are mostly wet
> aquatic systems are more strongly saturated – big eats small
> transmission of information – use of chemical, visual, and auditory cues differ in aquatic vs terrestrial ecosystems
> aquatic systems are more patchier
> light limitation – less water underwater
are life spans generally shorter or longer in aquatic systems
shorter – so dynamics are easier to observe rapidly
what is intertidal
zone between high and low tide component
what causes the variety in tidal ranges
shape of ocean basin and how they determine the response of the water to the gravitational pull of the moon
what do intertidal organisms need to deal with
desiccation stress (removal of water)
variable salinity
why was rocky intertidal where a lot of ecology took place
strong gradient of environmental conditions
accessible
many organisms are : easy to count, slow, lack emotional appeal (societally okay to experiment on) , population changes happen rapidly
what is a sessile organism
fixed in one place
and are arranged in horizontal bands as a function of tidal height
what is a fundamental niche
conditions where a species could inhabit
what is a realized niche
conditions where a species does inhabit in presence of competition and predation
what determine upper limits of niche
tolerance and physical factors such as desiccation
what set lower limits of niche
set by biological factors such as predation and competition
what do the distributions of sessile organisms tell us
they define realized niche of a species and are a signal of strong gradients in stress and species interactions
what can species interactions define
physical niche of species
ex: space competition. defines lower boundary of some species
how do ecosystem engineers affect diversity
increase
what level of diversity has the highest diversity
intermediate
dynamic state is between competitive domination and nothing
how do burrowing animals affect intertidal sediments
mix it, which aerates it
what are the different depths of intertidal sediment
biogenetic mixing depth - where critters like to live
anaerobic (low oxygen depth) - critters = :(((
what is an ecosystem engineer
species that create, modify, or maintain physical habitat for themselves and other species
what are the types of ecosystem engineer
allogenic - organisms that form habitat by transforming materials from one state to another (ex: beavers)
autogenic- organisms that form habitat with their own physical structure (ex: trees)
what are autogenic ecosystem engineers referred to when they are abundant
foundation species
what does the presence of foundation species define
the structure and abiotic conditions of the ecosystem
what are the impacts of foundation species
increase habitat complexity
change water flow patterns
recruitment rates
sediment erosion and deposition
nutrient cycling
primary productivity
examples of foundation species
kelp forests glass sponge reefs mollusc - beds eel grass coral
what are foundation species linked to
alternative stable states
presence/lack of foundation species can shift identify of ecosystem
what is a subsidy
movement of resources or material that boost the productivity of the recipient ecosystem
does the donor ecosystem or the recipient ecosystem control subsidy
usually donor - controlled
what are scavenger communities in subtidal ecosystems often driven by
resource subsidies
why might subsides have complicated impacts on the food web dynamics
interference competition exploitative competition scramble competition facilitation subsidized predation
what determines the dynamics of lakes
interactions between physical, chemical, and biological components of the lake
explain relationship between temperature and density
<0 degrees : water freezes (low density), it floats
between 0 and 4 degrees : water is less dense at cooler temperatures
above 4 degrees : warmer water floats
how do salts and dissolved substances affect density
make water heavier
what is stratification
when there is a relationship between water, temperature, and depth
usually warmer at top layer
what is reverse stratification
when there is ice, water is coldest at top layer
what sets the stage for the seasonal dynamics of lakes
stratification
turnover
what is turnover
when lakes go from stratification in the summer to unstratified
often occurs during fall and is driven by cooling temperatures (decreasing density differences) and wind
what does water do to light
it attenuates (reduces it) it
light is absorbed by water and scattered by particulate matter dissolved in it
how does algae affect light
the more algae in the water, the less light can penetrate it
what is respiration
uses o2 and breaks down sugars to release energy
does respiration need light
no
what determines rates of photosynthesis and respiration
nutrients (phosphorus and nitrogen)
light (photosynthesis only)
temperature
what is lake trophic status
useful classification of lakes based on their nutrients, o2, production, and light
what are the categories of lake trophic status
oligotrophic - clear, low nutrients, low photosynthesis, low respiration
mesotrophic – intermediate clarity and nutrients
eutrophic – high nutrients, which leads to high production at the surface, which shades out lower regions causing low photosynthesis and high respiration rates (low o2)
what are the different layers of thermal stratification
epilimnion - surface, warm layer
metaliminion - middle, mixed layer
hypolimnion - cool, bottom layer
what were the key findings of Soule 2004
species extinction is generally expected. to reduce bioturbation, but the magnitude of reduction depends on the functional traits of individual species , risk of extinction, and order in which species are lost
- extinction and order in which species go extinct govern the ecosystem - level consequences of biodiversity loss
what were the key findings of Bertness, Callaway
The whole ecosystem is determined by one species (or group of species). These species often have positive impacts on biodiversity (Bertness and Callaway reading) and can profoundly influence many important ecosystem processes.
what were the key findings in Carpenter
food chain structure (number of trophic levels) can cascade down the food web to control primary productivity
