Chapter 5 Protists: Protozoa and Algae

Protists have little in common with each other except for they are all eukaryotes that are usually aquatic are animal-like, plant-like, or fungus-like two main groups important to marine environments: protozoa and algae

Protozoa animal-like organisms heterotrophic unicellular organism no cell wall, no chloroplast means “first animal” test = exoskeleton / shell made of calcium carbonate

Protozoa pseudopodia – extension of the cytoplasm that protrudes; used for locomotion and feeding

Foraminiferans mostly bottom dwelling thin retractable pseudopodia found in limestone and chalk beds

Foraminiferans white cliffs of Dover in England and pink beaches of Bahamas

Radiolarians marine planktonic organisms found in the open ocean uses pseudopodia to capture food spherical shell made of glass (silica) with radiating spines

Ciliates have hair-like cilia which are used for locomotion and feeding found on seaweed, on the gills of clams, in the intestines of sea urchins, and on the skin of fishes most common example is Paramecium

Algae plant-like organisms autotrophic have chloroplasts lack stem, leaves, and roots can be unicellular or multicellular

Ecological Importance of Protists important part of the marine food chain algae are producers similar to land plants protozoa are primary consumers that are food for larger organisms algae make oxygen as a by-product of photosynthesis

Human Importance of Algae used in food potential use of fuel because more efficient than corn used in research to make agar (bacteria medium) and gels (gel electrophoresis) used in agriculture as fertilizer, in livestock feed

Algae-Animal Partnership Zooxanthelle is a type of dinoflagellate that lives inside the tissues of animals (anemones, giant clams, coral, nudibranchs, jellyfish) have a mutualistic relationship with corals; ( benefit / benefit )

How does this mutualistic relationship work? Corals provide a protected environment and compounds needed for photosynthesis to zooxanthellae. In turn, zooxanthellae provide food as products of photosynthesis to coral.

How does this mutualistic relationship work? This gives corals a boost of nutrients, so they can secrete the calcium carbonate skeleton that serves as the foundation for coral reef. This important relationship represents a highly efficient exchange of nutrients in a nutrient-poor environment.

Harmful Algal Blooms (HAB) when algal multiplies rapidly it changes color the discolored water (green, brown, red, or orange) can be caused by microorganisms like dinoflagellates, diatoms, cyanobacteria hazardous because the microorganisms may produce toxins that can poison fish and shellfish

Harmful Algal Blooms (HAB) toxins can have detrimental effects on marine food chains can affect marine animals like turtles, dolphins, manatees, and sea lions sea lion deaths are now almost annual events along the southern California coastline

HABs and Humans people can be harmed by a HAB by eating fish or shellfish that have been exposed to a HAB most common way to be affected by HABs is by eating poisoned shellfish cooking doesn’t kill toxins

HABs and Humans diarrhetic shellfish poisoning – nausea, vomiting, diarrhea neurotoxic shellfish poisoning – neurologic symptoms (tingling fingers and toes) paralytic shellfish poisoning – numbness, paralysis, respiratory failure

What Causes HABs?

What Causes HABs? increase in nutrients may lead to algal blooms rivers carry fertilizer run-off that eventually make their way to the ocean introduction of new microorganisms on ships brought to new sites that have a lack of predators, leading to an overpopulation of algae warm water also seems to be linked to HABs