Final Exam Concepts Part II

Question 1

Oligotrophic Gyre

Answer 1

An oligotrophic gyre is a ring-like system of ocean currents rotating clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere caused by the Coriolis Force. They generally form in large open ocean areas that lie between land masses.

Question 2

Biological Pump

Answer 2

The ocean’s biologically driven sequestration of carbon from the atmosphere to the deep sea.

Question 3

Thermocline

Answer 3

A zone in the water column that shows a sudden change in temperature with depth. The main thermocline is the zone where the temperature change marks the transition between the warm surface water and the cold deep water.

Question 4

Surface Mixed Layer

Answer 4

The upper layer of water that is mixed by wind, waves, and currents.

Question 5

Picoplankton

Answer 5

The component of the plankton that consists of extremely small organisms, 0.2 to 2 microns in size. They are too small to catch in a standard plankton set. They perform primary production in nutrient-limited areas.

Question 6

Surface:Volume Ratio

Answer 6

The amount of surface area relative to the total volume of an organism. As size increases, S:V decreases.

Question 7

Él Niño

Answer 7

Large-scale changes in atmospheric and ocean current patterns in which, among other things, warm surface water in the Pacific Ocean moves further to the east than normal. Él Niño refers specifically to the warming of the surface water in the Eastern Pacific.

Question 8

Know (in a general way) the location of oligotrophic gyres in the world’s oceans.

Answer 8

They are found in both the Northern Hemisphere and the Southern Hemisphere.

Question 9

Understand why the gyres are oligotrophic (i.e., have relatively low productivity).

Answer 9

There is a low level of phytoplankton which means less productivity.

Question 10

Understand the Biological Pump, and its role in the distribution of inorganic nutrients (and CO2) between the surface mixed layer and the deep ocean.

Answer 10

The biological pump is the ocean’s biologically driven sequestration of carbon from the atmosphere to the deep sea. It is the part of the oceanic carbon cycle responsible for the cycling of organic matter formed by phytoplankton during photosynthesis (soft-tissue pump), as well as the cycling of calcium carbonate (CaCO3) formed by certain plankton and mollusks as a protective coating.

Question 11

Know the relative level of primary production in oligotrophic gyres (compared to other ecosystems on earth), both in terms of primary production per area, and total global primary production.

Answer 11

The levels of primary production in oligotrophic gyres are extremely low (100 gC) compared to tropical rainforests which produce around 1200 gC. As far as global primary production goes, the open ocean has a higher level of primary production as compared to the tropical rainforests due to the fact that it makes up a much larger total area of the globe.

Question 12

Understand the importance of picoplankton as primary producers in oligotrophic gyres.

Answer 12

Together, they account for about 95% of the primary productivity in the ocean and about half of all primary productivity on earth. They are important primary producers because they can survive and are basically the food source for the area.

Question 13

Know what sorts of organisms directly consume these picoplankton.

Answer 13

Micro-zooplankton, such as copepods, ciliates, flagellates, and krill, eat picoplankton.

Question 14

Understand how surface:volume ratio varies with size, and why this matters to phytoplankton in these environments.

Answer 14

As sizes decreases, the ratio increases, enabling the phytoplankton to consume the scarce amount of nutrients available in those environments.

Question 15

Know the relative length of food chains in the gyres compared to other marine environments, and understand the consequences of these differences to upper levels of the food chain.

Answer 15

In the open ocean, there are 6 trophic levels which result in lower levels of nutrients being transmitted on each level. This ultimately leads to lower fish production. Open ocean (gyre): 6 trophic levels, continental shelf: 4 trophic levels, upwelling regions: 3 trophic levels.

Question 16

Understand the relationship between the trade winds and the sea surface temperature in the eastern equatorial Pacific. Know how Él Niño affects the trade winds, and how this, in turn, affects sea surface temperatures.

Answer 16

When Él Niño occurs, trade winds slacken, and upwelling ceases. Surface temperatures rise significantly. If the water current is moving Northwest, the trade winds blow Southwest.

Question 17

Know the approximate frequency of Él Niño events, and understand (in a general way) the far reaching (~global) effects of these events. Be aware that we have just experienced one of the largest Él Niño events in recorded history.

Answer 17

Él Niño occurs in 2-7 year intervals.

Question 18

Mesopelagic Zone

Answer 18

The pelagic environment from a depth of approximately 100-200m to 1000m. Sometimes called the Twilight Zone. Not enough light in this zone for photosynthesis.

Question 19

Tubular Eyes

Answer 19

Specialized eyes of many midwater animals that allow acute upward or downward vision.

Question 20

Photophores

Answer 20

An organ that produces bioluminescence. An organ that emits light.

Question 21

Bioluminescence

Answer 21

The production of light by living organisms.

Question 22

Diel (Daily) Vertical Migration

Answer 22

A pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The migration occurs when organisms move up to the epipelagic zone at night and return to the mesopelagic zone of the oceans or to the hypolimnion zone of lakes during the day.

Question 23

Counter-Illumination

Answer 23

The emission of light by midwater animals to match the background light.

Question 24

Know the sorts of environmental conditions encountered by organisms in the mesopelagic and deep ocean, with respect to food supply, light level, temperature, and pressure.

Answer 24

In the Mesopelagic zone, there is enough light to see if the organism has well-developed eyes but not enough light for photosynthesis. In the Deep Ocean there is no light at all. The only food they have is what carbon moves down from the biological pump cycle. Temperature decreases and pressure increases in these zones, and the number of organisms living in these zones decreases.

Question 25

Over what depths is there enough light to support photosynthesis? Vision?

Answer 25

From 0-100 meters, there is enough light to support photosynthesis. Vision is possible all the way up to 1,000 meters deep.

Question 26

Be familiar with how the abundance of organisms varies with depth from the surface to the deep oceans, and why.

Answer 26

There are 100 to 1,000 less organisms living in the Deep Ocean and Mesopelagic zone than in the surface mixed layer because the only food they have is what carbon moves down from the biological pump cycle.

Question 27

Know the general characteristics of mesopelagic fishes, and understand the commonalities and differences between the characteristics of vertical-migrators and non-migrators.

Answer 27

Mesopelagic fish have large eyes that see in low light, a large mouth compared to their body, they have photophores, which are organs that emit light (bioluminescence), and small body size. Vertical Migrators live in the mesopelagic zone but travel upwards to the surface mixed layer to gather food. They are strong swimmers and have well-developed bones and muscles. They also have a swim bladder. Non-migrators reside solely in the mesopelagic zone and are ambush predators, conserving energy waiting for food to come to them. They have an expandable gut.

Question 28

Know the common pattern of diel (daily) vertical migration, and understand why many organisms undergo this migration.

Answer 28

During the day, they live in the mesopelagic zone, but at night, they migrate upwards. Some scientists believe they migrate with the light level. They undergo this journey to gather food.

Question 29

Be familiar with the functions of photophores among both mesopelagic and deep-sea fishes.

Answer 29

Photophores are organs that emit light, sometimes through bioluminescent symbiotic bacteria. Used for many different reasons:
- Counter-Illumination, decoys for defense, lures for prey, to aid vision, and attract mates

Question 30

Know the general characteristics of deep-sea fishes, and how these compare with the characteristics of mesopelagic fishes.

Answer 30

Deep ocean fishes have small eyes, small in body size, flabby muscles, reduced/nonexistent swim bladder, extremely large mouth, and some have bioluminescent lures.

Question 31

Hydrothermal vents

Answer 31

A deep-sea hot spring where heated seawater forces its way up through the crest.

Question 32

Chemo-autotrophy

Answer 32

An organism, typically a bacterium, that derives energy from the oxidation of inorganic compounds.

Question 33

Photo-autotrophy

Answer 33

Organisms that carry out photosynthesis. Using energy from sunlight, carbon dioxide and water are converted into organic materials to be used in cellular functions such as biosynthesis and respiration.

Question 34

Giant Tube Worms

Answer 34

Are marine invertebrates in the phylum Annelida found in the intertidal and pelagic zones.

Question 35

Hemoglobin

Answer 35

A blood protein that transports oxygen in many animals.

Question 36

Thermophilic

Answer 36

An organism that thrives in high temperatures between 41°C and 122°C (106°F and 252°F). They need to heat to live, because high temperatures allow for their metabolism to function and for them to grow.

Question 37

Know what hydrothermal vents are, and where on the ocean floor they are located.

Answer 37

Hydrothermal vents form in a volcanically active areas often on mid-ocean ridges where earth’s tectonic plates are moving away. They are the result of sea percolating down through fissures in the ocean crust. They exist because the earth is both geologically active and has large amounts of water on its surface and within its crust. They may form features called black smokers. This is a chimney composed of the salts from hardened lava and water. At the mid-ocean ridge, the plates are diverging.

Question 38

Understand the effect of pressure on the boiling point of water.

Answer 38

Pressure increases with temperature because at higher temperatures, the molecules are moving faster. Boiling occurs when the pressure reaches or exceeds the surrounding pressure from the atmosphere. So, more pressure = higher boiling point. The effect of pressure on boiling point gradually decreases as the pressure increases, though.

Question 39

Understand the role of chemo-autotrophic bacteria as primary producers in vent environments.

Answer 39

While most autotrophic organisms use light as the energy source to convert CO2 into organic carbon, chemo-autotrophy uses the chemical energy from sulfide.

Question 40

Know the source of energy for chemo-autotrophic bacteria.

Answer 40

Use chemical energy from sulfide.

Question 41

Understand the nature of the symbiosis between giant tube worms (and other vent invertebrates) and chemo-autotrophic (sulfide oxidizing) bacteria. Understand the role of the unusual tube worm hemoglobin in this symbiosis.

Answer 41

Giant tube worms do not have mouths or digestive tracts; they are filled with chemo-autotrophic bacteria. The worms supply the bacteria with sulfide and oxygen and receive organic matter in return. The bacteria live inside the tube worms, which have a bright red tip. The redness comes from the large amounts of hemoglobin. The hemoglobin brings the oxygen and the sulfur to the bacteria so it can perform chemosynthesis. Other animals like mussels, calms vent barnacles, and crabs use this method to gain energy.

Question 42

Greenhouse Effect

Answer 42

The retention of heat in the lower atmosphere due to the presence of carbon dioxide, water vapor, and other greenhouse gases that allow solar light energy to penetrate to the Earth’s surface but block the transmission of heat energy back into space.

Question 43

Greenhouse Gases

Answer 43

The primary greenhouse gases in Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone.

Question 44

Biological Pump

Answer 44

The ocean’s biologically driven sequestration of carbon from the atmosphere to the deep sea.

Question 45

Understand how the greenhouse effect works.

Answer 45

The earth absorbs light energy from the sun and releases the energy as infrared radiation. Eventually, the amount of light energy and infrared radiation will even out. The atmosphere acts like a blanket and reflects some of the radiation back into earth, making it a warmer environment. The infrared radiation escaping the atmosphere will eventually balance out the light energy coming in.

Question 46

Understand the influence of the earth’s atmosphere on its average temperature.

Answer 46

Without an atmosphere, the balance would be at 0°F. With the atmosphere, the temperature would be at 57°F.

Question 47

Be familiar with the important greenhouse gases in the earth’s atmosphere.

Answer 47

Carbon dioxide: Not the most effective of the greenhouse gases, but the most prevalent in the atmosphere. Some other gases include water vapor, methane, nitrous oxide, ozone, and CFCs.

Question 48

Understand why the CO2 concentration in the deep ocean is high.

Answer 48

The Gyres use up the most carbon because of the carbon cycle and the biological pump. If the biological pump stopped working, the carbon from the deep ocean would come up to the surface mixed layer and the amount of carbon in the atmosphere would double.

Question 49

Know whether the ocean today is a net source or a net sink for atmospheric CO2, and why.

Answer 49

The oceans are responsible for taking our extra carbon dioxide emissions. They are the largest sink of carbon, having a thousand times more carbon than the atmosphere.

Question 50

Understand the relative scientific certainty associated with different aspects of the global climate change phenomenon (observations vs. causes. vs. predictions).

Answer 50

It is extremely likely that human influence has been the dominant cause of global warming. During the winter, there is an increase in CO2 because the amount of respiration is higher than the amount of photosynthesis. During the summer, there is a decrease because photosynthesis outweighs respiration. The carbon dioxide concentrations at Manuna Loa have been increasing since the 1950s.
Observations of global climate change: temperature, sea level, arctic sea ice, glaciers, and ocean pH. Humans have increased their CO2 emissions exponentially, leading scientists to believe that humans are the main cause behind global warming. The IPCC has increased its certainty that humans are the main cause of global warming.

Question 51

Be aware of the strong scientific consensus regarding the causes of observed global climate change over the past century.

Answer 51

Methane and nitrous oxide concentrations in the atmosphere are both increasing similar to carbon dioxide.
Over the century, the average temperature of the earth has increased by 0.9°C. The sea level elevation has
been increasing by 100 feet in the last 100 years because the ocean temperature has been heating up and
expanding. The Arctic Sea Ice Caps have been decreasing compared to their average size. There is a
decrease in the amount of ice to reflect the heat away from Poles. The continental glaciers are also
disappearing, which shows that the increase in temperature is happening in all environments.

Question 52

Know how atmospheric CO2 concentration has changed over the past 50 years or so, and why.

Answer 52

Right now the CO2 is the highest it has been in at least 800,000 years of data. Human industry has added a good amount of CO2 to the atmosphere, but CO2 only increases at a rate of 4.2ppm/year (book says 1.5ppm/year).

Question 53

Understand the yearly variation in atmospheric CO2 concentration, as well as the long-term trend.

Answer 53

The concentration of CO2 in the earth’s atmosphere has been increasing over the past two centuries. 2015 was the hottest year on record.

Question 54

Know (in a general way) how the concentration of CO2 in today’s atmosphere compares with the concentration over the past 400,000 years.

Answer 54

Right now, the CO2 is the highest it has been in at least 800,000 years of data.

Question 55

Know (in a general way) the observed trend in average global temperature over the past century. Be aware of the geographic variation in this trend.

Answer 55

Over a century, the average temperature of the earth has increased by 0.9°C. Some places have gotten much warmer than normal, like the arctic.

Question 56

Know (in a general way) the observed trend in sea level and ocean pH over the past few decades, and understand the reasons for each of these trends.

Answer 56

Sea level has increased and ocean pH has decreased (acidified). The decrease in pH is due to the high amount of CO2 and other nutrients being increased in the ocean. Sea level rise causes are explained below.

Question 57

Understand how the melting of (i) Sea-Ice and (ii) Land-Ice affect sea level.

Answer 57

The melting of sea-ice does not affect sea level. This ice in the water has already dispersed the water, therefore there is no effect. Land-ice, however, causes the sea level to rise when melted. The ice melts into the ocean, therefore increasing the overall water level.

Question 58

Know (in a general way) the observed trend in Arctic Ice extent and the size of glaciers over the past few decades.

Answer 58

The size of glaciers has decreased along with the Arctic Ice. This has created a possible new route of travel for ships, which could have possible economic results.

Question 59

Understand the “positive feedback” between reduced arctic sea-ice extent and sea water temperature.

Answer 59

“Positive feedback” is a term that refers to the impact that sea-ice melting has on seawater temperature. As more ice melts, there is less ice left to reflect the sunlight back out of the atmosphere. Ice reflects a significantly higher amount of sunlight than open ocean. This results in sea temperature rising at a faster rate as more ice melts.