1. Marine Life and the Marine Environment
General Oceanography
Chapter 11
Marine Life and the Marine Environment
November 26-28, 2013
Young-Heon Jo

2. Chapter Overview
There are more than 250,000 identified marine species.
Most live in sunlit surface seawater.
A species’ success depends on the ability to
find food,
avoid predation,
reproduce, and
cope with physical barriers to movement.
Marine organisms are adapted to the ocean’s physical properties.

3. Classification of Life
Three domains
Archaea (고세균영역)
심해열수공서식
Bacteria (세균영역)
자색박테리아, 남주류
Eukarya (진핵생물영역)
DNA, 에너지 공급

4. Classification of Living Organisms
Five kingdoms
Monera
Protoctista
Fungi
Plantae
Animalia

5. Five Kingdoms of Organisms
Monera (원핵생물계)
Simplest organisms, single-celled
Cyanobacteria, heterotrophic bacteria, archaea
Protoctista (원생생물계)
Single- and multicelled with nucleus
Algae, protozoa
Fungi (균계)
Mold, lichen

6. Five Kingdoms of Organisms
Plantae (식물계)
Multicelled photosynthetic plants
Surf grass, eelgrass, mangrove, marsh grasses
Animalia (동물계)
Multicelled animals
Range from simple sponges to complex vertebrates

7. Taxonomic Classification
Carolus Linnaeus – 1758
Developed basis of modern classification of organisms
Taxonomy – systematic classification of organisms
Physical characteristics
Genetic information

8. Taxonomy Kingdom (계) Phylum (문) Class (강) Order (목) Family (과)
Genus (속)
Species (종)
Fundamental unit
Population of genetically similar, interbreeding individuals

9. Classification of Marine Organisms
Plankton (floaters)
Nekton (swimmers)
Benthos (bottom dwellers)

10. Types of Plankton Most biomass on Earth consists of plankton.
Phytoplankton
Autotrophic
Zooplankton
Heterotrophic

11. Other Types of Plankton
Bacterioplankton
Virioplankton
Holoplankton
Entire lives as plankton
Meroplankton
Part of lives as plankton
Juvenile or larval stages
Macroplankton
Large floaters such as jellyfish or Sargassum
Picoplankton
Very small floaters such as bacterioplankton

12. Life Cycle of a Squid

13. Nekton (유영동물) Independent swimmers Most adult fish and squid
Marine mammals
Marine reptiles

14. Nekton

15. Benthos (저서생물) Epifauna live on the surface of the sea floor.
Infauna live buried in sediments.
Nektobenthos swim or crawl through water above the seafloor.
Benthos are most abundant in shallower water.
Many live in perpetual darkness, coldness, and stillness.

16. Benthos

17. Hydrothermal Vent Communities
Abundant and large deep-ocean benthos
Discovered in 1977
Associated with hot vents
Bacteria-like archaeon produce food using heat and chemicals.

18. Number of Marine Species
More land species than marine species
Ocean has relatively uniform conditions
Less adaptation required, less speciation
Marine species overwhelmingly benthic (98%) rather than pelagic (2%)

19. Adaptations of Marine Organisms
The marine environment is more stable than land.
Organisms in the ocean are less able to withstand environmental changes.
Marine animals do not risk desiccation.

20. Adaptations of Marine Organisms
Physical support
Buoyancy
How to resist sinking
Different support structures in cold (fewer) rather than warm (more appendages) seawater
Smaller size

21. Adaptations of Marine Organisms
High surface area to volume ratio
Unusual appendages to increase surface area
Oil in micro-organisms to increase buoyancy

22. Viscosity and Streamlining Adaptations
Streamlining important for larger organisms
Less resistance to fluid flow
Flattened body
Tapering back end

23. Temperature and Marine Life
Narrow range of temperature in oceans
Smaller variations (daily, seasonally, annually)
Deep ocean is nearly isothermal

24. Ocean Temperature More stable than land for four reasons
Higher heat capacity of water
Ocean warming reduced by evaporation
Solar radiation penetrates deeply into ocean layers
Ocean mixing

25. Cold vs. Warm Water Species
Smaller in cooler seawater
More appendages in warmer seawater
Tropical organisms grow faster, live shorter, reproduce more often
More species in warmer seawater
More biomass in cooler seawater (upwelling)

26. Temperature and Marine Organisms
Stenothermal (협온성)
Organisms withstand small variation in temperature
Typically live in open ocean
Eurythermal ( 광온성)
Organisms withstand large variation in temperature
Typically live in coastal waters

27. Salinity and Marine Organisms
Stenohaline (헙염성)
Organisms withstand only small variation in salinity
Typically live in open ocean
Euryhaline (광염성)
Organisms withstand large variation in salinity
Typically live in coastal waters, e.g., estuaries

28. Salinity Adaptations Extracting minerals from seawater
High concentration to low concentration
Diffusion
Cell membrane permeable to nutrients, for example
Waste passes from cell to ocean

29. Osmosis
Water molecules move from less concentrated to more concentrated solutions
Osmotic pressure
In more concentrated solutions
Prevents passage of water molecules

30. Marine vs. Freshwater Fish

31. Dissolved Gases
Animals extract dissolved oxygen (O2) from seawater through gills.
Gills exchange oxygen and carbon dioxide directly with seawater.
Low marine oxygen levels can kill fish.
Gill structure and location varies among animals.

32. Gills on Fish

33. Adaptations to Marine Environment
Camouflage through color patterns
Countershading – dark on top, light on bottom
Disruptive coloration – large bold patterns, contrasting colors make animal blend into background

34. Camouflage and Countershading

35. Divisions of the Marine Environment
Pelagic (open sea)
Neritic (< 200 meters) and oceanic
Benthic (sea floor)
Subneritic and suboceanic

36. Pelagic Environment Divided into biozones
Neritic Province – from shore seaward, all water < 200 meters deep
Oceanic Province – depth increases beyond 200 meters

37. Oceanic Province Further subdivided into four biozones Epipelagic
Only zone to support photosynthesis
Dissolved oxygen decreases around 200 meters
Mesopelagic
Organisms capable of bioluminescence common
Bathypelagic
Abyssopelagic

38. Dissolved Oxygen with Depth
Dissolved oxygen minimum layer (OML) about meters
Nutrient maximum at about same depths
O2 content increases with depth below

39. Ocean Zones Based on Light Availability
Euphotic – surface to where enough light exists to support photosynthesis
Disphotic – small but measurable quantities of light
Aphotic – no light

40. Benthic Environments Supralittoral Subneritic Suboceanic Littoral
Sublittoral
Inner
Outer
Suboceanic
Bathyal
Abyssal
Hadal

41. Organisms of the Deep