class 2 aqua

Describe the relationship between gross primary production, net primary production, and respiration

net primary = gross primary - cost of respiration

List factors that impact light penetration in aquatic environments

inorganic nutrients, water clarity, depth

Define turbidity, euphotic zone, and compensation depth

turbidity: cloudiness of water due to particles

euphotic zone: layer of water where there is sufficient light for photosynthesis to occur

compensation depth:

Explain how a Secchi disk is used to assess turbidity

if you can see a Secchi disk deeper than the water is clearer if it has to be shallower to be seen its cloudier water

Draw a graph of photosynthetic rate vs. light intensity and explain how and why both vary with depth

theres a sweet spot for light intensity depending on the organism. too bright can inhibit but too little can be not enough to power photosynthesis

Describe the factors that can influence the compensation depth

Explain how the depth of the euphotic zone can influence which organisms function as the dominant primary producers in a system

Speculate on how human activities might perturb primary producers and ecosystems

human activity can cause increased sediment runoff/turbidity which then favors cyanobacteria over other primary producers which affects food chain

Define macro-, micro-, and limiting nutrients

macro: required in large amounts

micro: required in smallest amounts and often serve as catalysts in metabolic reactions

limiting: the nutrient available in shortest supply

Explain why inorganic nutrients are important

Explain what a limiting nutrient is

the nutrient available in shortest supply

Describe the experimental design for single and multi-nutrient enrichment experiments

1 control

others different combination of nutrients and look for changes in phytoplankton population which tells us which nutrients are important

Predict what the results would be if a nutrient was limiting in a single or multi-nutrient enrichment experiment

• in single you would see growth. tells us thats one of the limiting nutrients

• in multi you would see growth if it was not the limiting nutrient but if you didn’t see growth then there is limiting and potentially co-limiting

List & describe confounding factors associated with interpretation of results from single and multi-nutrient enrichment experiments

• Multi-nutrient co-limitation: more than one essential nutrient is limiting

• Biochemical co-limitation: one nutrient may facilitate uptake or assimilation of a second nutrient

• Community co-limitation: Different phytoplankton species may be limited by different nutrients

Interpret data from nutrient enrichment experiments to identify potentially limiting nutrients

Discuss the changes in lake Apopka and the underlying factors that caused it to transition from a clear water lake with lush submerged aquatic vegetation to a green-water

lake dominated by phytoplankton

Identify the cause of of the phytoplankton blooms in the Long Island Bays and which nutrient was limiting in these Bays

people ate a lot of ducks (that were raised on farms along waterways) lots of duck waste that entered these water sources which caused phytoplankton blooms. blooms impacted other organisms making them unable to respire or feed efficiently. conducted experiment which had control and nitrogen and phosphate enriched flasks and determined. determined nitrogen as limiting nutrient.

Explain what the ELA is and describe the results of the enrichment experiment of lake 226.

Experimental lakes area

one side of lake added nutrients and other side added other nutrients and looked for differences in phytoplankton levels

one side resulted in algal bloom (carbon and nitrogen) other side did better with phosphorus showing it as the limiting nutrient

Explain what processes and factors lead to phosphorus typically being limiting in freshwater systems and nitrogen being limiting in marine systems.