During the first section we discussed basics of marine science. Now we’ll begin taking a look at marine life

1. During the first section • we discussed basics of • marine science. • Now we’ll begin taking • a look at marine life and • all of it’s diversity.

2. The Microbial World

4. Introduction • We begin our survey of ocean life with the smallest of marine organisms, the bacteria and archea. • Both groups contain members which are capable of photosynthesis an are known as primary producers. • These primary producers are responsible for directly or indirectly feeding most marine organisms.

5. From the largest… Whale shark, Rhincodon typus

6. To the smallest… Octopus larvae

7. Prokaryotes • The first organisms we will consider will be the prokaryotes. • Prokaryotes are the smallest, simplest (and oldest) organisms around. • Unlike other animals we will study, prokaryotes lack a nucleus. • Two main categories of prokayotes are Archea and Bacteria

8. Marine bacteria take on many • shapes, including spheres such • as Thiomargarita namibiensis, • a benthic bacteria which can be • seen with the naked eye. • Other shapes include rods, rings • and spirals. • Some may form into • large calcium containing • mounds (stromatolites). • Still others break down organics • and cycle nutrients. Stromatolites, Exuma Cays, B.I

10. Life and Death • Perhaps one of the most interesting evolutions of bacteria cocerns the development of bioluminescence and toxins (tetrodotoxin). • Whether used as a flashlight fish’s trick for attracting prey, or giving a good buzz to your sushi, bacteria occupy some amazing niches in the marine world!

11. Cyanobacteria:Red Tide • Planktonic spp. such as cyanobacteria (which can cause red tides) often multiply very rapidly. • The contain red pigments. • They also can be caused by dinoflagellates (photo).

12. Archea: Extreme Conditions • Archea are similar to bacteria, but they are able to tollerate conditions most other bacteria wouldn’t dream of being caught around. • Some are able to tollerate temperatures near hydrothermal vents (176°F, 80°C).

13. Prokaryotic Metabolism

14. How do you eat?? • Many bacteria (autotrophs) are perfectly capable of feeding themselves, making their own organic compounds by photo- or chemosynthesis. • Bacterial photosynthesis is different than that found in plants (i.e. you might produce S instead of O2). • Some autotrophs which produce methane as biproducts are being used to meet our energy needs.

15. How do you eat (cont.)?? • Bacteria which utilize other sources of carbon (organics) to exist are known as heterotrophs. • Many heterotrophs are involved in decay processes and some even exist in anoxic (no O2) conditions. • Still others are actively fixing nitrogen from gas to molecules which other animals can use as food during primary production.

16. Unicellular Algae • Being composed of one cell isn’t an evolutionary dead end. • Alagae, Diatoms, Dinoflagellates, and Radiolarans all have been aound for millions of years (if not billions). • Being eukaryotic, unicellular organisms such as these use a variety of methods to eat, metabolize, and reproduce. • As a group these organisms are known as Protist!

17. Diatoms contain many organelles that enable them to exist under potentially harsh conditions. • Most diatoms constist of strikingly delicate outter shells of SiO2 (frustules) which provide limited protection and light penetration.

18. Diatoms reproduce asexually (cell division) and sexually (auxospore), depending on external conditions.

19. Dinoflagellates exhibit two flagella which permit movement. Theca Groove One flagella is located within the groove and the other is located at the lower end (not visible). Dinoflagellate, Gonyaulax polyedra

20. Slilicoflagellates are characterized by star-shaped internal skeletons. Some may be used for aging marine sediments.

21. Still others, like these Coccolithophorids are surrounded by shells of calcium carbonate (CaCO3) and are responsible for significant primary production! Umbilicosphaera sibogae

23. Some eukaryotes are more like animals than like plants! • In fact, having a single cell is about the only thing that these critters have in common with other eukaryotes we have observed. • Foraminiferans and radiolarans utilize specialized pseudopodia (spine-like projections) to capture food.

24. The outer shell, or test, is made of CaCO3 and serves as a protective structure.

25. Ciliates are protozoans which utilize cillia for feeding and in some cases locomotion.

27. Bahia Fosforescente, Puerto Rico