Aquatic Biodiversity and Ecosystem: Study Guide

Natural Resources

* materials and energy found in nature that are essential or useful to humans.
* provided natural services for free.
* often **overexploited** due to substitution
* **Can be ecological or Economic**
* These are **actions that are** provided by the environment via natural means.
* **Have no cost to humans**

Natural Resources: examples

 Climate moderation, nutrient cycling, reducing storm impact

Analogy to “goods” in a economy

the “goods” that nature is providing for humans to use

the “verbs” (natural resources)

the actions that NATURE provides

Define Economic or Ecological Services:

* Allows for transportation via waterways
* Provides natural pharmaceuticals
* Provides food for humans
* Provides habitat & nursery areas for organisms
* Allows for nutrient cycling
* Provides minerals
* Moderation of the climate

economic

economic

ecological

ecological

ecological/economic

ecological/economic

ecological

Water Salinity: definition

amount of salt found in a body of water

Salt Water Salinity

* refers to water with salt levels HIGHER THAN 35 ppt (parts per thousand)
* found in mostly **oceans**

\

Brackish Water Salinity

* water with variable salinity (usually changes with tide) .5 to 35ppt **(salt 5 ppt > than 35 < ppt) (parts per thousand)**
* Found most in **estuaries and bays**

Fresh Water Salinity

* Refers to water with salinity LOWER THAN .5ppt.
* Found in **rivers, streams, and lakes.**

Properties of Water: High Heat Capacity

* Wate**r holds onto the heat** well.


* One factor that allows for temperature regulation on earth.

Properties of Water: Ability to form hydrogen bonds

* allows for **cohesion/adhesion.**
* This leads to the **high surface tension** of water.
* *Makes the* ***transportation of substances*** *around the body* ***easier***

Properties of Water: “Universal solvent”

* **Dissolves** many substances (usually polar / charged substances)
* By dissolving chemicals, **water allows chemical changes to take place much more rapidly.**

Properties of Water: Density of water 

* Is lower when frozen = ice floats
* Floating ice keeps bodies of water from freezing solid

Freshwater Ecosystems

* Water may be standing (**lentic**) or flowing (**lotic**).
* Lentic System = standing water (lakes/ponds)

Lotic System = flowing water (river/stream)
* Accounts for about 2.2% of earth’s surface

Freshwater Ecosystem: Zones

* **Four** major zones
* Littoral
* Limnetic
* Profundal
* Benthic

Littoral Zone

* Where rooted plants grow high sun / O2
* photosynthesis occurs

Limnetic Zone

* The surface of water away from where rooted plants are.
* Dissolved oxygen is high here.
* organisms: algae and phyto (plant) plankton (drifter)

Profundal Zone

* deeper in the water column,
* less sunlight to support photosynthesis **(result of low light in the profundal zone)**
* Dissolved oxygen is low here.
* organisms: fish/consumers, nekton (strong swimmers)

Benthic Zone

* Found at the bed of freshwater ecosystems.
* Decomposers are dominant.
* Nourished by falling detritus from layers above.
* organisms: Benthos (organisms living in the Benthic Zone)

Freshwater Ecosystem: 2 Categories

Lentic System = standing water (lakes/ponds)

Lotic System = flowing water (river/stream)

Lotic Freshwater System: 3 Stages

* Source
* Transition
* Floodplain

Source Stage (1st Stage)

* **high** relief (slope)
* water velocity is **high.**
* **high rate** of erosion
* **erosion is the dominant force.**

Transition (2nd Stage)

* **moderate** relief (slope)
* water velocity is **moderate.**
* **moderate rate of erosion**
* **some** deposition
* **large sized sediments (ex: gravel) will fall out first**

Floodplain (3rd Stage)

* **low** relief (slope)
* water velocity is **low.**
* **high rate of deposition**
* **small sediments fall out.**
* **most agriculture is found** in floodplains because it is **high in minerals (silk and clay)** and gets **deposited in the soil**

Deposition

the process in which sediments fall out in suspension.

Erosion & Deposition in Lotic Systems: **Factors influencing erosion rate:**

* Water velocity
* Riverbed rock type
* Stream gradient
* Channel shape / roughness

**Factors in deposition rate:**

* Water velocity
* Particle size
* Sediment load

rates of erosion and deposition in terms of relief in the lotic system. Explain how erosion and deposition occur at different rates in different zones in the lotic system

Erosion is the dominant force in the first stage, so it is at a much higher rate due to the high relief

\
In the transition stage, the relief is moderate so the erosion rate starts to decrease but the deposition rates increase

\
In the floodplain stage, the relief is low so it has the highest rate of deposition

What is a wetland?

land covered by water for all or part of the year **excludes marine systems.**

What type of water salinity is in a wetland?

can be brackish OR freshwater.

\
Found in coastal (brackish) or inland (freshwater)

what type of water environment is wetlands?

* BOTH lentic and lotic
* Includes **swamps** (forested wetland), **marshes** (characterized by grasses), seasonal wetlands.

Wetlands Globally

* Despite their essential role in global climate regulation, **wetlands remain undervalued by policy** and decision-makers in national plans. 

Wetlands: Biggest Threats

* water drainage (making land for agriculture to make farms)
* pollution
* unsustainable use
* invasive species (plants can suck up a lot of water that takes away from other organisms)


* disrupted flows from dams.


* sediment dumping from deforestation.
* soil erosion upstream

Economic Services: Wetlands

* __**Flood control**__ - root systems, and soils act as a sponge, this capacity to hold water also regulates the water cycle.
* __**Water purification**__ - certain plant species found in wetlands have adaptations that allows for the breakdown of pollutants. Bacteria / decomposers help to filter water as well.
* __**Carbon sequestration**__ - Microbes in soils of wetlands store carbon, in addition to the diverse plant species found there.
* __**Habitat for biodiversity**__ - Many plant and animal species found around this kind of biome. 
* __**Recreational opportunities**__ - Wetlands are found in many national parts and reserves. (Think everglades)

Why is salinity significant abiotic factor to classify aquatic ecosystems?

you have different adaptations of organisms in different ecosystems so organisms that adapt in freshwater cannot adapt in brackish water

Watershed Definition

local areas of water drainage where water moves from a higher elevation to a lower elevation

How does the watershed concept relates to runoff over the land

The concept relates to runoff because once watershed occurs, the watershed collects surface runoff and delivers it to larger streams and rivers

How does land use affect water quality in a watershed?

it affects it due to agriculture, mining practices and urbanization

Why do floodplains have a HIGHER rate of productivity.

Since floodplains has regular flooding that can deposit nutrients and water. So that low velocity allows for smaller particles to get deposited like silk and clay. Those minerals get deposited in the soil and help crops grow on farms.

Three major types of sediments

* silk
* clay
* sand