lecture 5 - aquatic biomes

Name 3 major ecological functions of soil organisms

• nutrient cycling and decomposition

• Soil structure formation

• Carbon sequestration

• Plant growth regulation

Differentiate between lotic and lentic systems

Lotic = flowing water (rivers and streams)

Lentic = still water (lakes, ponds, wetlands)

Define pelagic vs benthic zones

Pelagic = open water column

Benthic = bottom of the water body

List the oceanic depth zones from shallowest to deepest

Epipelagic → mesopelagic → bathypelagic → abyssal → hadal

What is upwelling and why’s it important

Wind driven process that brings nutrient rich deep water to the surface. Fuels high primary productivity (phytoplankton blooms)

Name the horizontal and vertical zones of rivers

Horizontal = wetted channel, active channel, riparian zone

Vertical = water column, benthic zone, hyporheic zone, phreatic zone

Describe the vertical layers of a lake

• Epilimnion - warm oxygenated

• Metalimnion - thermocline

• Hypolimnion - cold low oxygen

What is thermal stratification

Separation of lake water into temperature layers, often stable under seasonal turnover

• warm top, cold bottom

Compare oligotrophic and eutrophic lakes

Oligotrophic = low nutrients, clear water, high oxygen

Eutrophic = nutrient rich, turbid, low oxygen from decomposition

Differentiate between bogs and fens

Bogs = rain fed, acidic, mosses/carnivorous plants

Fens = groundwater fed, variable pH, grasses/sedges

Define a species niche

The range of abiotic and biotic conditions where a species can survive, grow, and reproduce

Explain the difference between a fundamental and realized niche

Fundamental = abiotic range under which a species might live in the absence of interactions with other species

Realized = actual conditions occupied after competition/ predation constraints

What is the competitive exclusion principle

Two species with identical niches cannot coexist indefinitely, one will outcompete the other

What is hutchinsons n-dimensional hyper volume concept

Describes a species niche as a multidimensional space defined by environmental variables critical to survival and reproduction

What is niche partitioning and how does it promote coexistence

When species use shared resources differently (by time, location, or method), reducing direct competition

What are some ways you can characterize the niche

• historical data on distribution

• Invasive species - habitat conditions found in region of origin

• Climate modeling (temp, precipitation, seasonality)

• Soil type, presence of predation and competitors