Protista: The Algae and Heterotrophic Protists
Chapter 15
Ecology of Protists
Oldest eukaryotes~1.8 billion years old
Most protists are aquatic: either in oceans or marine coastlines or freshwater lakes, ponds and streams
Few live terrestrially
Contain > 12 phylaKingdom Plantae contains ~11 phyla
Grouping the Protists
Kingdom Protista
plants, fungi, or animals
Paraphyletic
Made up of single celled, colonial, or multicelledeukaryotes
Multicellular eukaryotes are not differentiated into tissues though
Ecology of the Protists
Plantae) but of the aquatic systemsPlay similar ecological roles of plants
Fix CO2 release O2Represent the base trophic level
Remember cyanobacteriaAutotrophic plankton phytoplankton
Plankton
This occurs when calcium carbonate accumulates as scales covering phytoplankton
When they die this calcium carbonate sinks to the bottom
Plankton
Haptophytes and dinoflagellatesproduce sulfur compounds
Leads to formation of clouds when excreted as sulfur oxidesReflect sunlight global cooling
Rapid increases of
rain
Plankton
Also have extremely rapid responses to nutrient input
Often cause toxic blooms, red tides and hypoxia
Algae (kelp)
intertropical regions. Yet if in any country a forest was destroyed, I do not believe nearly so many species of animals would perish as would here.
-‐Charles Darwin in reference to the kelp forests off Tierra del Fuego, Chile June 1834
Kelp
Kelp also weigh heavily upon ocean ecology Whereas terrestrial forests require + 30 years to develop kelp forests can grow in ~ 3 yearsTerrestrial forests are strongly associated with 3 phyla (Arthropoda, Annelida, and Chordata)
Kelp forests are associated with > 10 phyla!
Chordata, Arthropoda, Annelida, Echinodermata, Bryozoa, Cnidarian, Mollusca, Platyhelmenthes, Brachiopoda, Porifera + more
Kelp
Functions of kelp forests:Provide a basal trophic level
Dampen wave action on shore
Reduce light and facilitate low light understory species
Provide shelter for predator prey stabilization
Kelp
May also fix nutrients on landArid islands with productivity rely upon kelp detritus
Fixed C and N from bird and mammal feces in island systems is often correlated with shoreline to area ratio
More shoreline = more washed up kelp = more C and N fixed through birds and mammals = greater productivity
Kelp
Channel Islands California
Kelp
What does the Japanese whaling industry have to do with Pacific kelp forests?Post WWII whaling targeted the great whaleGreat whales represented a huge amount of energy removed from the system ~ 200x 109 caloriesThe predator of the great whale, the killer whale, has to use other energy sources to fill energy demands
A single male requires > 240,000 calories a day!!!
Kelp
Killer whales started
chainFrom 1990-‐ 2000 sea otter populations declined ~ 25% per year!Even when great whale populations are low, predation index is still relatively low
Kelp
The energy calculated from estimated prey sea otters (around 25% of the population) accounts for roughly more than 1 killer whale pod, or around 1/40 of the population demand
Kelp
Kelp?Sea otters eat sea urchinsSea urchins eatupon kelpPredation of sea otters by killer whales releases sea urchins and contributes to rapid deterioration of kelp beds
Approx 1/10 the size of 12
Lessons From Kelp!
Not an isolated incident!The same anthropogenic mediated depletion of top down predation of sea urchins occurred in the Atlantic
Removal of cod, crabs, and lobsters freed sea urchins from predation
Top down pressure has significant impacts upon ecosystems!
Removal of wolves from Yellowstone led to nearly 0 recruitment of aspens due to increased elk herbivory
Lessons From Kelp!
Biodiversity is important!California kelp beds have suffered numerous apex predator depletions and shifts and kelp deforestation is brief at max
More indirect interactions buffer the whole trophicsystem from cycling out of control with the loss of one species
Diverse food webs allow for competitive interactions to buffer population explosions
Lessons From the Office?
worst enemy. And the enemy of my enemy is my friend. So Jim, is actually my friend. But, because he is his own worst enemy, the enemy of my friend is my enemy so actually Jim is my enemy. But-‐-‐Dwight Schrute
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