what is the standing crop?

Let's break down this concept into simpler terms:

*What is a Standing Crop?*

              A standing crop refers to the total amount of living organisms (plants and animals) present in a body of water (like a lake or river) at a given time.

*Five Main Groups:*

        These organisms are divided into five main groups:

1. Phytoplankton (microscopic plants)

2. Bottom flora (plants attached to the bottom)

3. Bottom fauna (animals living on the bottom)

4. Zooplankton (microscopic animals)

5. Fishes

*Nutritional Chain:*

   These groups are connected through a food chain:

      Phytoplankton & Bottom flora (producers) → Zooplankton & Bottom fauna (consumers) → Fishes (top consumers)

*Productivity:*

            The number and size of these groups show how productive the water is.

*Pyramid of Aquatic Life:*

     

   Imagine a pyramid with:

- Phytoplankton at the base (largest amount)

- Bottom flora and fauna in the middle

- Zooplankton and fishes at the top (smallest amount)

This pyramid shows how energy and nutrients flow from producers to consumers.

*Key Points:*

- The size of each group depends on the ones below it.

- Changes in one group affect others.

- Measuring the standing crop helps understand the ecosystem's productivity.

*Example:*

Weber Lake's pyramid has:

- Phytoplankton: 70-80% of total biomass

- Bottom flora: 10-20%

- Bottom fauna: 5-10%

- Zooplankton: 2-5%

- Fishes: 1-2%

This distribution varies between lakes, but the pyramid shape remains.

Now, imagine this concept like a layered cake:

- Phytoplankton is the largest layer (foundation)

- Each subsequent layer (bottom flora, fauna, zooplankton, fishes) is smaller

- Energy and nutrients flow from the bottom up

*Distribution of Biomass in Lakes*

• Dissolved Organic Matter (DOM): 60%
• Fish: 0.5% (less than 1%)
• Other Animals: 5% (zooplankton, bottom fauna, etc.)
• Plants (phytoplankton, bottom flora): remaining percentage (approximately 35%)

*Efficiency Comparison*

- soft-water lakes: 2.5 times more efficient in converting plants into animals 

- Hard-water lakes: less efficient

*Lake Comparison*

Lake Type	Phytoplankton	Zooplankton	| Bottom Fauna	Fish
Soft-water (Weber, Nebish)	High	Moderate	Moderate	Low
Hard-water (Green, Mendota)	Lower	Lower	| Lower	Low

 

 

 

Key Findings*

1. DOM dominates lake biomass.

2. Soft-water lakes convert plants into animals more efficiently.

3. Fish comprise a small percentage of total biomass.

4. Plant-to-animal ratio varies between lake types.