exam

Primary Productivity

1) Use radioactive C-14 (tagged) H14CO3- carbon is tagged and monitored through photosynthesis process in marine organisms light bottle to dark bottle technique- difference in carbon uptake- measure of gross productivity- done over depth. 2) Measure chlorophyll content of ocean from satellites

Zooplankton

1) Zooplankton (animal); heterotrophic plankton. 2) Most numerous primary consumers of the ocean 3) Graze on phytoplankton (diatoms, dinoflagellates, etc) Copepods- most abundant zooplankton Account for 70% of individuals

Limit Productivity

1) water- not limiting 2) Carbon dioxide or carbon- not limiting 3) *Inorganic nutrients- can be limiting (nitrogen, phosphorus, iron, etc.) 4) Sunlight- can be limiting (depth) Autotrophs- Inorganic nutrients required to 1) construct large organic molecules and 2) construct skeletons or shells *Lack of nutrients- most common factor limiting primary productivity. Too little light- limits productivity- Very little primary productivity below 330 ft (100 meters)- too much light is also a problem (quantity)

Photosynthesis equation

6CO2 + 6H2O >C6H12O6 + 6O2

Total oceanic productivity

75-150 g C fixed /m2/yr

Feeding relationships

A. Primary Producers or Autotrophs- self-nourishment- make own food- photosynthetic & chemosynthetic organisms B. Heterotrophs- organisms such as animals that must consume other organisms- because they are unable to synthesize own food molecules 1 0% of consumed energy is stored in consumer's flesh- the rest is lost as heat and work by organisms.

Respiration equation

C6H12O6 + 6O2 > 6CO2 + 6H2O +

Global distribution of plankton/Seasonal variations of phytoplankton productivity

For the most part, distribution of phytoplankton corresponds to distribution of major nutrients.

Marine Vs Terrestial Production

Marine total production about equal to terrestrial production

Depth of greatest productivity

Most of biological productivity of ocean occurs in the upper half of the photic zone- area near surface- called euphotic zone (good light)- less than 2% of world's ocean volume.

Holoplankton

Spends the majority of their life in plankton form

Diatoms, dinoflagellates, coccolithophores, silicoflagellates

dominant and best studied, 5,600 species Larger species barely visible to the unaided eye, Most are autotrophs Most have two whip-like projections (flagella)- one drives organism forward and the other rotates it in the water. Widely distributed Reproduce- simple fission Responsible for "red tide"- red coloring in ocean Produce potent toxins- by some species- to filter feeders (oysters, clams, scallops, mussels) toxic to man, not filter feeders. Zooxanthellae- single-celled dinoflagellates that are symbiotic with coral (live within coral), single-celled autotrophs covered with disks of calcium carbonates (Coccoliths).

Phytoplankton bloom peaks in the spring for the northern temperate zone

higher of the two peaks- Indicates plankton bloom in spring caused by increasing illumination. Smaller of the two peaks-Northern fall bloom caused by nutrients moving

Near-shore production vs. open-ocean production

primary production nearly always higher than open ocean because nutrient levels are highest near the continent's 1- coastal upwelling and 2- land runoff plankton most abundant there and production. Open Ocean - 1) Tropics- water generally deficient in surface nutrients Tropic oceans away from land Nearly devoid of visible plankton- due to strong thermocline which discourages vertical mixing necessary to bring up nutrients from the depths. *Tropical coral reefs- exceptions to the general rule of low tropical productivity. 2) Polar regions Winter months- has weeks or months of darkness- severely limit productivity Summer months- 24-hour daylight, upwelling nutrients- leads to plankton blooms, but doesn't last because nutrients are rapidly removed. *Antarctic- more productive than Arctic because Arctic Ocean is surrounded by landmasses that limit water circulation and nutrient upwelling nutrients depleted quickly. Southern ocean (Antarctic) enriched by water upwelling, rich in nutrients higher productivity. 3) Temperate and Subpolar Zones *Greatest productivity- due to 1-dependable light and 2- moderate nutrient supply *Greatest of any open ocean area. North temperate- higher of the two peaks- Indicates plankton bloom in spring caused by increasing illumination. Smaller of the two peaks-Northern fall bloom caused by nutrients moving toward the surface.

Compensation depth

respire as they photosynthesize- use some of the carbohydrates and O2 they produce.