Phytoplankton

• Translates from Greek “free-floating plants”• Misnomer – some float, others have limited

motility (spontaneous movement)

Source: http://visindavefur.hi.is/svar.php?id=4815

Diatoms•Typically bloom in the spring

•Dissolved silica is limiting nutrient (frustules – cell wall made from silica)

•Cold water environments

•P or Si limited

Source: http://www.jeolusa.com/tabid/323/AlbumID/570-22/Default.aspx

Source: http://www.waterencyclopedia.com/Oc-Po/Plankton.html

Green Algae

• Typically bloom in summer

• Usually P-limitedSource: http://www.fcps.edu/islandcreekes/ecology/green_algae.htm

Source: http://bennettkids.homestead.com/algae.html

Dinoflagellates

• Typically bloom in summer

• Flagellated, motile

• Occasionally toxic (red tide)

Source: http://biology.unm.edu/ccouncil/Biology_203/Summaries/Protists.htm

Source: http://mac122.icu.ac.jp/biobk/BioBookDiversity_3.html

Blue-green algae

• Typically bloom in late summer/early fall

• Low N requirement (N-fixing organisms)

• Low sinking velocities (gas vacuoles)

• Warm water

Source: http://apexlyo.com/page8.html

Source: http://www.stockpix.com/stock/nature/botany/indexb.htm

Eutrophication

• Refers to the excessive rate of addition of nutrients, usually in reference to anthropogenic activities that increase the concentration of N and P to natural waters

• Results in the excessive growth of plants, including phytoplankton

• Negative water quality impacts:– Green color, decreased transparency, excessive weeds– Hypolimnetic loss of dissolved oxygen– Loss of species diversity (fish kills)– Taste and odor problems

Sources: http://library.thinkquest.org/04oct/01590/pollution/eutrophication.html

Source: http://www.cost869.alterra.nl/

Source: http://drake.marin.k12.ca.us/stuwork/rockwater/Eutrophication/index.html

Source: http://www.cop.noaa.gov/stressors/extremeevents/hab/features/hypoxiafs_report1206.aspx

Alexander et al. 2008. Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the Mississippi River Basin. ES&T 42: 822-830