lec 5 - Aquatic Systems and Ecological Niches -BIOL 208

Vocabulary practice flashcards covering ocean currents, vertical aquatic zones, river and lake structures, lake productivity categories, wetlands, and ecological niche concepts.

Gyres

Large ocean circulation systems created by horizontal surface currents, driven by winds, the Coriolis effect, and land masses

What 3 things are gyres driven by?

1. winds

2. coriollis effect (solar energy heats surface,  influences heart circulation in atmospheric cells)

3. land masses (keeps circulation in check)

Gyres are important for of exchange of which 3 things?

1. energy (movement of organisms)

2. salts

3. nutrients (can distribute nutrients across oceans = high productivity)

Ekman spiral

vertical spiral - coriolis effect starts movement of surface layers - each layer shifts at 45 degree angle & wind force diminishes as each layer gets deeper -
causes net water transport $90^\circ$ from the surface wind direction - causes coastal upwelling

Coastal upwelling

wind-driven process - wind blows parallel to coast & surface waters move offshore, causing deeper nutrient-rich waters to rise & increase primary productivity (ex. N, F for photoplankton) - can cause algal blooms

Are all algal blooms bad?

depends on intensity & frequency
short time = good
long time = bad (influenced by urban centres & organisms releasing toxins)

Limnology

study of inland aquatic systems, connects lotic (running) and lentic (standing) freshwaters

Lotic systems (aquatic biome)

Freshwater biome - running waters rivers, streams

Lentic systems

Freshwater biome - still waters - lakes, ponds, and wetlands

aquatic zones

broad divisons that ca be used for all aquatic systems + oceans, includes pelagic & benthic zones

Pelagic zone (broad aquatic zone)

in water, above bottom of aquatic substrate (anything higher than hadal)

Benthic zone (broad aquatic zone)

substrate at bottom of aquatic environments (can include hadal & abyssal)

Epipelagic zone (vertical ocean zone)

top layer (down to 200m)
photic zone, captures & absorbs solar energy = organisms have lots of colour diversity to attract mates & prey
warm temp
lots of organism diversity and phytoplankton

Mesopelagic zone (vertical ocean zone)

middle

Bathypelagic zone (vertical ocean zone)

deep ocean (down to 4000m)
organisms adapted to no sunlight (dull colours), cold temps, high pressure (would dissolve at surface), food scarcity (have slow metabolism, large mouths & bioluminescence to attract prey)

What drains most of the landscapes on earth (Lotic system)?

rivers, from rain run off & groundwater

Wetted channel (Horizontal river zone)

contains water year-round

Active channel (Horizontal river zone)

edges of river, water levels rise and low depending on season

Riparian zone (Horizontal river zone)

vegetated edges of river, tree roots absorb groundwater, organisms adapt to terrestrial & aquatic enviro - being submerged in summer & dry in winter

water column (vertical river zone)

open water in wetted channel

Benthic zone (vertical river zone)

between bottom of river & sediment

Hyporheic zone (vertical river zone)

where surface water and groundwater mix = specific living conditions for organisms (hyporheos)

How are hypoheos adapted to living in the Hyporheic zone (vertical river zone)?

tend to be string-like and flat to easily move through sediments & river currents, fast cycles

Phreatic zone (vertical river zone)

groundwater with low O2 = specific living conditions for organisms (phreatobites)

How are phreatobites adapted to living in the Phreatic zone (vertical river zone)?

pale colours, no eyes, sensing antentas (similar adaptations to deep ocean),

Littoral zone (horizontal zone in lakes & ponds, Lentic system)

shallow edge, where aquatic plants grow along a lake or pond where sunlight penetrates to the bottom substrate.

Limnetic zone (horizontal zone in lakes & ponds, Lentic system)

open water

Epilimnion zone (vertical zone in lakes & ponds, Lentic system)

warm, upper layer, absorbs solar energy, supports high diversity, (phytoplankton, fish, birds) - similar to photic zone in ocean)

Metalimnion zone (vertical zone in lakes & ponds, Lentic system)

thermocline: rapid decrease in temp

Hypolimnion zone (vertical zone in lakes & ponds, Lentic system)

dark, cold, low O2 due to decomposition of organic matter

thermal stratification

seasonal layering of a lake into distinct zones with different density & temp (vertical zones in lakes & ponds)

What happens to the vertical zones in lakes & ponds in spring & fall?

no thermal stratification, layers mix, are same temp & density, brings nutrients from bottom to top = agal blooms in summer

Oligotrophic lake
nutrients:

primary productivity:

O2 levels:
colour:

low (N, P)
low
high
clear

Eutrophic lake
nutrients:

primary productivity:

O2 levels:
colour:

high
high (from phytoplankton = agal blooms)
low (consumed by decomposers)
green

Dystrophic lake
nutrients:

primary productivity:

O2 levels:
colour:

low
low (organic & humic acids, from pine needles, changes pH = lake more acidic)
low
brown

Bogs

Freshwater wetlands sourced by rainwater, characterized by acidic peat soils, mosses, and carnivorous plants.

Fens

Freshwater wetlands sourced by groundwater, characterized by variable or neutral pH, grasses, sedges, and mosses.

Ecological niche

The range of environmental factors and biological interactions under which an organism can survive, grow, and reproduce.

Fundamental niche

The complete range of environmental conditions and resources a species can potentially occupy in the absence of species interactions like competition or predation.

Realized niche

The actual set of environmental conditions and resources a species occupies when restricted by biotic interactions with other species.

Competitive exclusion principle

The ecological principle stating that no two species relying on the exact same limiting resources can occupy the same realized niche indefinitely.

Hutchinsonian niche

A concept defining a species niche as an $n$-dimensional hypervolume, where $n$ is the number of environmental factors influencing survival and reproduction.

Niche partitioning

The process by which competing species divide limiting resources by using them in different ways, locations, or times, enabling them to occupy distinct realized niches and coexist.