Oceanography Lecture 6 (Ch.9)

Scyphozoans

(bell-shaped jelly fishes) -Bell-shaped body with fringe of tentacles -Microscopic - 20 m -Move by muscular contraction

Zooplankton

- Feeding modes: Grazers: feed on phyto- and bacterioplankton. Carnivores: feed on other zooplankters. Omnivores: feed on both phytos and zooplankters. - Holoplankton - entire life as plankton (dominate the open ocean) - Meroplankton - spend only a part of life as plankton (common in shallow coastal-ocean waters)

Hydrozoans

- Jelly fishes - Gas chamber for float and sail -Colony of 4 individuals (Float, tentacles, mouth, reproduction) - 6 inches in width

3 kinds of photic zones

- Most of the biological productivity of the ocean occurs in an area near the surface called the euphotic zone (or photic zone). - Below the euphotic zone lies the disphotic zone. - Below the disphotic zone lies the dark aphotic zone, the vast bulk of the ocean where sunlight never reaches.

Endotherm:

- high, stable internal temp - generate their own heat - high metabolism

Ectotherm:

- internal temperature depends on surroundings

Metabolic rates

- the measure of an organism's energy use - Metabolic rate determines the speed with which organisms move, react, and live. - Directly related to interior temperature

Picoplankton

- this category encompasses most other types of plankton, which are very small. Might account for up to 80% of photosynthetic activity in some parts of the ocean.

Plankton

-Found in nearly all aquatic habitats. -Small organisms suspended in water column. -Incapable of swimming against major currents (in contrast to Nekton) -Great diversity; nearly all phyla represented. - Includes phytoplankton (photosynthetic autotrophs) and zooplankton (heterotrophic)

Standing crop

-Total plant biomass per unit area or unit volume (Net primary production) - (amount grazed by herbivores)

Dinoflagellate Bioluminescence

-light up when disturbed (defense) -chemical reaction

Zones are classified by

1) Location 2) Behavior of the organisms found there.

Major types of phytoplankton

1. Diatoms - the dominant and most productive of the photosynthetic plankton (see marine sediment notes) 2. Coccolithophores - small single celled autotrophs (see marine sediment notes) 3. Dinoflagellates - widely distributed single-celled phytoplankton; use flagella to move

Global Primary Production (4 areas)

1. Upwelling areas -Most productive but smallest area 2. Coastal ocean -Intermediate productivity and area 3. Open ocean -Least productive, but largest area 4. Estuaries & Salt Marshes - Very productive

Adding what element to the ocean would increase the biological pump?

Adding iron (limiting factor) - unsustainable and environmental effects unknown

Trophic pyramid

At successively higher trophic levels: # of individuals decreases total biomass decreases Organism size increases Generation time increases (transfer efficiency 10%)

What is the largest animal on earth ever?

Blue whales

Oceanic biological pump

Carbon and nutrients moved to deep sea •About 90% of surface biomass is decomposed in surface ocean •About 10% sinks to deeper ocean •Only 1% organic matter not decomposed in deep ocean

Binomial nomenclature

Classification system in which each species is assigned a two-part scientific name (genus then species)

Epifauna vs Infauna

Epifauna (Animals on the surface of ocean floor) Infauna (Animals that burrow into top 1-5 cm of ocean floor)

Net primary production:

Gross minus respiration; supports higher trophic levels

Phylum

Group of closely related classes (shared body plan)

Hypertonic

Having a higher concentration of solute than another solution (cells shrivel up)

Hypotonic

Having a lower concentration of solute than another solution (cells swell up)

hypoxia vs anoxia

Hypoxia- Low Oxygen. Anoxia- No Oxygen.

Meroplankton

Juvenile and larval stages of nektonic and benthic organisms

Phytoplankton and zooplankton vs nektons

Occur in pelagic (open water) habitats Phytoplankton and zooplankton are drifters Nektons are swimmers

How do substances move through cells?

Osmosis (uses cells partially permeable membrane to move from high to low), diffusion (movement from high to low concentration) and active transport (requires energy)

convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments (for example ichthyosaurs, penguins and dolphins all have flippers)

Primary production:

Rate of production of energy rich organic compounds (usually measured in gC m-2yr-1)

Photosynthesis

The process used by most producers to convert the sun's energy to food energy. 6CO2 + 6H2O = 6glucose + 6O2

Chemosynthesis

The production of food from inorganic molecules in the environment. The energy to bond carbon atoms into glucose comes from breaking the chemical bonds holding the sulfur and hydrogen atoms together in hydrogen sulfide

Gross primary production:

Total amount produced

Harmful algal blooms (HABs)

Toxic phytoplankton blooms -6% of phytoplankton species cause HABs. -Most HABs are caused by dinoflagellates (red pigments). - The color will be determined by the pigment of phytoplanktons - Due to addition of nutrients from sewage, agriculture, aquaculture

Plankton need to be near sunlight..

and float. To prevent sinking: • increase resistance (drag) -Greater surface area, shape, projections • increase buoyancy -Oil drops, air bubbles, lower tissue density

Primary productivity in the tropics is

fairly constant throughout the year

•Phytoplankton biomass controlled by

interaction of sunlight, stability of surface water, and nutrients in surface water

Osmoregulation:

the active regulation of water and salts to retain a constant internal water pressure

Isotonic

when the concentration of two solutions is the same

How do HABs harm the water?

• Bacterial decomposition of decaying phytoplankton can reduce oxygen levels and often lead to fish kills. • Dense phytoplankton shades benthic photosynthesizers (seagrass, seaweeds) • Toxins are not immediately harmful, but will accumulate in the tissue of filter-feeding organisms (shellfish).

Controls on Primary Production

• Light -Variations of light intensity with latitude and season -Variations of light intensity with depth -Water column stability and solar radiation (vertical transport) •Nutrients (primarily nitrogen and phosphorous) -Winter overturn -Storms and mixing -Seasonal cycles

6 Feeding Relationships

•Autotrophs - organisms that make their own food, also called producers. •Heterotrophs - organisms that must consume other organisms for energy •Trophic pyramid - a model that describes who eats whom •Primary consumers - these organisms eat producers •Secondary Consumers - these organisms eat primary consumers •Top consumers - the top of the tropic pyramid

Polar ocean productivity

•High in Southern Summer •Availability of sunlight and high nutrients due to upwelling of North Atlantic Deep Water -Surface divergence -No thermocline -No barrier to vertical mixing •Blue whales migrate to feed on maximum zooplankton productivity

Temperate ocean productivity

•Limited by both available sunlight and available nutrients •Highly seasonal pattern -Winter low (lots of nutrients, little sunlight) -Spring high (spring bloom) -Summer low (little nutrients, lots of sunlight) -Fall high (thermocline breaks down; fall bloom)

Copepods

•Microscopic or macroscopic •Shrimp-like •Consume ½ body weight each day •Herbivores, carnivores, parasites •Hard exoskeleton, segmented, joints •Majority of ocean's zooplankton biomass

Krill

•No bigger than ~ 5cm •Food for sea birds through largest whales •Prefer cold oceanic waters •Efficient grazers

Tropical ocean productivity

•Permanent thermocline is barrier to vertical mixing •Low rate of primary productivity (lack of nutrients) •High primary productivity in areas of -Equatorial upwelling -Coastal upwelling -Coral reefs •Symbiotic algae •Recycle nutrients within the ecosystem

Phytoplankton

•Primarily unicellular plantlike organisms (algae) •Cells are autotrophic (photosynthesis) and independent (even as chains) •Primarily microscopic -Exception: Sargassum: macroscopic floating algae

Dinoflagellates

•Second most productive group of marine algae •Unicellular, two flagella (can move toward light) •Armored cell wall (plates of cellulose) •Reproduce by cell division •Blooms turn water red, reddish-brown

What are the most important physical factors for marine organisms?

•light •dissolved gases •temperature •acid-base balance •salinity •hydrostatic pressure •dissolved nutrients (nitrogen and phosphorus are main limiting nutrients)