coastal and cultural eutrophication Flashcards
what groups of organisms are the primary producers in estuaries and the ocean?
in lakes/ estuaries:
- submurged vascular plants (flowering vegetation like seagrass)
- macroalgae (non-flowering vegetation like seaweed)
in seas and lakes:
- diatoms (micro-algae, phytoplankton)
- dinoflagellates (plankton, can be producers or consumers)
can you define eutrophication?
occurs when limiting nutrient is introduced to aquatic system -> creates algae bloom
what does the term “limiting nutrient” mean?
essential plant nutrient that is in shortest supply relative to the needs of plants
examples of point and non-point sources of nitrogen pollution
point source:
- discharge sewage treatment plants
- groundwater systems of homes w/own septic system
non-point source:
- runoff from agricultural fields
- release from soil after clear-cutting
- deposition of N from air
what different changes can occur in estuaries as a result of eutrophication?
- can influence some kinds of dinoflagellates to stimulate toxic forms (Pfiesteria) which can kill fish by giving them sores and making them lethargic -> results in a lack of oxygen in water
- can kill seagrass because microflora grows as epiphytes on seagrass and shades it
- can create a dead zone
- block light from surface which kills diatoms at bottom of estuaries and decreases food availability for fish who eat diatoms
- cause blooms in toxic plankton species which decreases biodiversity
what environmental impacts can be caused by dinoflagellates?
urea influences some dinoflagellates like Pfiesteria to become toxic and make fish sick (sores and lethargic) which results in many fish dying -> decomposition takes up oxygen in water
what is the seasonal succession in marine waters?
in spring, diatom bloom (abundant nutrients) -> N becomes limiting -> dinoflagellates replace diatoms because they are more mobile and better at getting scarce nutrients
