Video 30 Aquatic Ecology


hi APES students welcome to video 30 on
aquatic ecology so when we talk about the different zones and different
aquatic life zones there are saltwater / marine and there’s also freshwater so
things like estuaries coastlines marshes swamps oceans those are considered to be
saltwater freshwater would be lakes and ponds streams and rivers and any Inland
Wetlands like marshes or swamps that are not going to be along the coast so these
are the different zones of the ocean um you want to know all the crazy detail
from this diagram but know that the bottom of the ocean is called the
abyssal zone on kind of the middle that is still getting a pretty good amount of
light would be the faithful zone and then the top portion of the ocean is
called the youth Adak this one is where a lot of the light is penetrating on you
also have the continental shelf over here off to the side and then you’ll
have the estuaries high tide coastal zone this is where most of your
biodiversity is going to be in the ocean so again the open ocean if you remember
does not actually have that much production going on if you remember our
NPP and GPP discussion so looking at the features of the ocean floor
you need to be able to answer these questions you don’t have to have an
actual diagram like this but just kind of be familiar with some of these terms
so the deepest place in our oceans is the ocean trench down here the type of
plate boundary that makes these trenches is a convergent plate boundary so where
one plate is going to be subducting going underneath the other plate that’s
where a trench storms sediment carried by rivers are deposited around here in
the continental margin and shelf area that’s going to be where all your
sediment is deposited plate boundary that is located at a mid-ocean ridge so
here’s a mid-ocean ridge basically an underground underwater mountain chain
and this is a divergent plate boundary that is making this and if you remember
divergent is where sea crust is actually getting formed and then it’s pushing out
on either sides going away from the boundary so here’s just another way of
looking at this again here’s the mid-ocean ridge here’s
where magma is coming up it will be pushing out on either side here’s gonna
be your trench over here and then here’s your abyssal zone that we just talked
about as well so looking at the different life zones of the ocean you
have plate plate planktonic means free-floating on to things like
phytoplankton zooplankton if it’s swimming in the ocean freely it’s called
neck tonic and then if it’s down at the bottom kind of you know scavengers
decomposers those are called benthic or benthos at the bottom so some limiting
factors in an aquatic life zone on basically what are things that limit the
amount of organisms that can live there you’re gonna have temperature light
clarity and turbidity dissolved oxygen and salt concentrations these are some
of the limiting factors another limiting factor this is specific to the ocean you
see this oxygen curve going down and then the corresponding carbon dioxide
curb kind of going up at the same time so the less oxygen you have the less
organisms you’re going to have more specific to having less oxygen they’ll
have to be adapted to that so looking at freshwater wetlands freshwater wetlands
are covered with freshwater for most of the year these things include marshes
and swamps Marsh contains non woody plants swaps or have woody plants those
are really the only difference here and most of our marshes and wetlands you’ll
notice down here are in the Southeast United States so a couple of different
things about why wetlands are important just be able to have a few they buffer
shorelines against erosion obviously kind of you know break the waves that
are coming through they trap and filter sediments nutrients pollution and all
those sorts of things they reduce flooding they protect agriculture
provide habitats for fish especially nursing grounds and they provide habitat
for endangered species as well so we’re going to look
at low-tech systems these are river systems we’re going to look at each one
of these different zones so the loading zones the first is the source on these
are your headwaters very steep they have high dissolved oxygen content the water
is moving very fast it’s also really cold so if I go back and look real quick
this is our source region Mountains transition is very slow and warm it’s
going to be lower dissolved oxygen we’re getting away from the fast-moving waters
so again here’s your transition zone floodplain area and then the floodplain
is flat meanders these are going to be very slow-moving waters you actually
start to get those curves which are the meanders the lowest amount of dissolved
oxygen they’re really quiet this is where your wetlands would be located
looking at the life zones of a lake it might be beneficial to draw like a
little bowl shape and then label these so benthic again is the bottom part so
we’re kind of keeping the alot of these terms similar benthic organisms at the
bottom of the ocean this is the benthic at the bottom of the lake profunda zone
is very deep but not quite at the bottom no photosynthesis is going to be
happening here very little Lynnette ik is the open area away from
the shoreline that gets a lot of the light and then the torold zone is going
to be to the shore to where plants can’t grow roots and this is going to be your
highest diversity there so when we classify different lakes or classifying
them based on nutrient content so we’re doing a eutrophication lab that’s kind
of what we’re talking about here so if it’s oligotrophic that means it’s very
nutrient poor on it looks like this lake it’s very clear there’s not a lot of
stuff growing in it if it’s you trophic that means it’s very nutrient rich you
might say a lot of the green algae things of that nature
so look at traffic lakes are very new again they’re nutrient poor they have
very steep banks they also have low net primary
activity they tend to be clear and they tend and not have as many populations on
so over time though things will go into lakes nutrients will be added and when
that happens you get a youth Adak lake sorry you trophic lake this is an old
Lake is very well nourished it’s usually shallower because sediment has built up
in the bottom that’s what leads to the turbidity it also has high net primary
productivity because it’s got a lot of nitrogen phosphorous in it and therefore
it’s got a lot of biodiversity so this is a natural process that over time
lakes go from oligotrophic to you terrific also think about in your fish
tank if you don’t clean it after a while it will eventually look like this this
is an algal bloom and the reason that it forms because you have excess nutrients
nitrogen and phosphorous usually it’s from this fish waste but you can also
get this in some other ways so cultural eutrophication is the process where
people are causing eutrophication to happen faster than it naturally would
also plants are using phosphorus and nitrogen and they’re growing out of
control mainly because of surface water runoff leading into the stream that
takes with it phosphorus and nitrogen from our fertilizers so because the
plants have grown out of control they’re now over populate and then they’re going
to die and after plants die bacteria decompose them in the process of
decomposition and this process uses up oxygen in the water which is your
respiration process and if you don’t know you do need to know this formula
opposite of photosynthesis so bacteria are going to use up this oxygen they’re
also releasing carbon dioxide into the system so therefore there’s no oxygen
left for aquatic life and they’re going to die just like these fish over here so
this will be an oligotrophic like you’re adding nutrients fertilizer and then
eventually you have a decrease and dissolved oxygen and the fish will die
so if it’s a hypoxic situation that means that oxygen is just reduced but
not completely gone if it’s anoxic that means there’s no oxygen left and you’re
gonna have big fish kills so this is a picture of a fish or a situation the
Outer Banks called the red tide this was a red
Oh bloom it was very toxic and the government was actually warning people
about getting in the water at all because it would be toxic to humans as
well as the organisms living in there and then here is what a fish kill might
look like basically they suffocate and they die and they’ll wash up on shore
very sad situation and as you can imagine this is not good for our
fisheries all right let me know if you have any questions you ready for quiz

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