Prelim 2 Flashcards
(192 cards)
1
Q
Drew Harvell Lecture:
What will happen by the year 2100?
A
By the year 2100, without changes, more than half of the world’s marine species may become extinct.
2
Q
Drew Harvell Lecture:
What are Marine Protected Areas (MPAs)?
A
Marine Protected Areas conserve the biodiversity of the oceans and maintain productivity of fish stocks.
3
Q
Drew Harvell Lecture:
How much of the land area is protected?
A
About 12% of the land area is protected in comparison to 1% of the world ocean and seas.
4
Q
Drew Harvell Lecture:
What organisms are in danger of extinction?
A
Sharks & rays and corals. Sharks & rays are in more decline than corals. Corals are in steep decline but not as bad as sharks & rays.
5
Q
What is the generation of CO2?
A
Respiration
6
Q
What is Net Primary Production (NPP)?
A
Net Primary Production is the difference between the amount of CO2 consumed by photosynthesis and the amount of CO2 produced by respiration.
It is the net gain or net loss of carbon within the cell.
7
Q
What happens to light levels below compensation light level?
A
Phytoplankton cells have insufficient light to photosynthesize to meet basal metabolic needs and cell respiration exceeds photosynthesis, leading to negative values of net primary production.
8
Q
What happens to phytoplankton at low light levels, optimal light levels, and very high light levels?
A
At low light levels, phytoplankton are light limited.
At optimal light levels, phytoplankton are light saturated
At very high light levels, phytoplankton are photoinhibited.
9
Q
What is compensation depth?
A
The depth at which ambient light intensity is equal to compensation light intensity.
10
Q
What is the nutrient dependency of primary production?
A
At low concentration, the dominant cell diameter of phytoplankton is 1 micrometer.
At middle concentration, the dominant cell diameter of phytoplankton is 10 micrometers.
At high concentration, the dominant cell diameter of phytoplankton is 100 micrometers.
11
Q
What are the four phytoplankton nutrients of interest to oceanographers and why?
A
The four phytoplankton nutrients are nitrogen, phosphorus, silica (for diatoms), and iron.
One of these four nutrients can be in short supply and limit growth of phytoplankton.
12
Q
What is the main source of nitrogen, phosphorus, and silica to the surface ocean?
A
Vertically mixing or upwelling of nutrient-rich deep-water to the surface.
13
Q
What is the main source of iron input to the surface ocean and where is iron mainly limited?
A
The main source is from dust blowing off the continents.
The Southern Ocean is one of the main iron limited regions.
14
Q
Light and nutrients in surface ocean?
A
Light is plentiful but nutrients are limiting.
15
Q
Nutrients and light in deep ocean?
A
Nutrients besides iron are plentiful but light is limiting.
16
Q
What are surface and deep waters separated by?
A
Thermocline
17
Q
When is primary production enhanced?
A
High light and high nutrients
18
Q
What does surface convergence of Ekman Layer in the subtropics (forced by Trade and Westerly Winds) form?
A
Mounds/lens of warm (low-nutrient) water including gyre rotation and downward surface layer velocity into deeper ocean.
19
Q
What happens to primary production if surface convergence makes it difficult for nutrients to move upward to surface ocean?
A
Primary production is low year-round in the subtropical gyres.
Low surface layer nutrients present through all seasons.
20
Q
What do easterly trade winds cause?
A
Surface waters to pile up in the west
21
Q
Where is thermocline deep and shallow?
A
Thermocline is deep in the west and shallow in the east.
22
Q
What happens to the proximity of thermocline near surface in the east?
A
It enhances upwelling of cold and nutrient rich deep water to the lighted region of the surface ocean and enhances biological productivity in the area.
23
Q
What is tidal mixing?
A
Tidal mixing happens in shallow continental shelf regions. It is seasonally steady and mixes water column from bottom to top and brings bottom water with rich nutrients to the ocean surface.
24
Q
What is coastal upwelling?
A
Coastal upwelling comes from Wind/Ekman Offshore Transport. It is seasonally variable and enhances upward movement of deep water with rich nutrients.
25
What is subtropical gyre primary production?
It is low primary production year-round because of persistent lens of warm water.
26
What is equatorial primary production?
It has a modest season in the Atlantic and strong interannual variation in the Pacific due to El Nino.
27
What is coastal primary production?
It is high year-round especially during upwelling periods in California, Chile, Northwest Africa, South Africa, and Arabian Peninsula.
28
What is the change in seasonal thermocline depth?
From spring to summer, there is warm water, buoyant, hard mixing, and shallow water.
From summer to winter, there is cold ocean surfaces not as buoyant and deeper water.
29
What happens to cells below the Compensation Depth?
They lose carbon because of the extreme dim light that allows positive net primary production (NPP).
30
Why does the average light level that phytoplankton experience over the course of a day becomes dimmer as mixing depth increases?
Cells spend most of the day below compensation depth in the dark.
31
What happens to cells below the Critical Depth?
Cells spent most of the day below compensation depth and lost carbon.
Net losses of carbon below compensation depth exceed net gains of carbon above compensation depth.
32
What happens to mixing depth in the winter?
The mixing depth is very deep in the winter.
| Light limited and nutrients abundant.
33
What happens to mixing depth in the spring?
The mixing depth is shallow in the spring.
| Light abundant and nutrients abundant.
34
What happens to mixing depth in the summer?
The mixing depth is very shallow in the summer.
| Light abundant and nutrients limited.
35
What happens to mixing depth in the fall?
The mixing depth is shallow in the fall.
| Light modest and nutrients modest.
36
What is deep vertical mixing in the winter?
It brings high levels of nutrients to the surface and causes phytoplankton to mix below the critical depth, making cells spend time in the dark and NPP light limited.
37
How is shallow thermocline formed in the spring?
The mixing depth is above the shallow thermocline and above the critical depth, so phytoplankton spend time high in the water column with abundant sunlight.
Nutrients are plentiful from winter mixing, so cells have abundant nutrients and sunlight, causing the formation of a spring bloom.
38
Why is there continued stratification in the summer?
Mixing is shallow and above critical depth, but nutrients are depleted and NPP is nutrient limited.
Polar ocean regions are the same as temperate ocean, but ice shelf melting enhances stratification.
39
What is the global distribution of annual net primary production (NPP)?
1. Global NPP is about 104 Gt C yr-1
2. Terrestrial NPP is about 54% of Global NPP
3. Oceanic NPP is about 46% of Global NPP
40
Why does the Open Ocean contribute more to the global ocean total NPP than the coastal regions?
Open Ocean (Trade Winds, Westerly Winds, and Polar Regions) show less intensities of primary production (NPP per square meter) in comparison to coastal regions (29%). The Open Ocean contributes most (71%) as a whole to the global ocean total NPP because of the vast areas of these regions.
41
What nutrient is limited in Station Aloha in the North Pacific Subtropical Gyre?
Phosphorus
42
What nutrient is limited in the Southern Ocean?
Iron
43
What nutrients limit growth of phytoplankton?
Nitrogen limits growth of phytoplankton in the ocean, but iron and phosphate may limit growth in certain oceanic regions.
44
What is global ocean primary production?
The global ocean primary production has same magnitude as the global terrestrial system.
45
Why is the rate of primary production per square meter in the open ocean low?
The region is vast, so the open ocean as a whole contributes to the total global ocean primary production.
46
What is a holoplankton?
```
Planktonic organisms that live their entire life in fluid
suspension.
Examples:
1. Copepods
2. Shrimp
3. Arrow Worms
4. Some Jelly Fish
```
47
What is a meroplankton?
```
Planktonic organisms that spend only part of their life in
fluid suspension.
Examples:
1. Crabs
2. Barnacles
3. Oysters
4. Fish Larvae
```
48
How are complex food webs simplified?
They are simplified by grouping/classifying all species into a small number of broad categories.
49
How is an individual organism's membership determined?
1. What are the main food sources of the organism?
| 2. Who are the main predators of the organism?
50
What is an autotroph (broad grouping)?
Group of organisms whose energy/carbon for growth comes from non-organic sources such as phytoplankton because they use sunlight and CO2 for their energy/carbon needs.
51
What is a heterotroph (broad grouping)?
Group of organisms whose energy/carbon for growth comes from previously formed organic carbon material.
such as herbivorous zooplankton because they consume phytoplankton for their carbon needs. Carnivores would also be heterotrophs.
52
What is a trophic level (refined grouping)?
A nutritional feeding level within a food chain or food web such as primary producer (autotroph), primary consumer (herbivore), secondary consumer
(first carnivore), and tertiary consumer (second carnivore).
53
Is the heterotrophic organism a primary consumer or a secondary consumer or a tertiary consumer etc…?
Optimal prey size is determined by the consumer’s mouth size and, as a rule-of-thumb, prey size is often about 1/10 the consumer’s size.
54
What two factors does Trophic Transfer Efficiency depend on?
Exploitation Efficiency and Gross Production Efficiency
55
What is Exploitation Efficiency?
The efficiency with which a consumer population is able to find, capture and ingest all of the potential prey present in the environment.
56
What is Gross Production Efficiency?
The physiological/biochemical efficiency of converting ingested prey into consumer biomass.
57
What is the formula for Trophic Transfer Efficiency?
Trophic Transfer Efficiency = (Exploitation Efficiency x Gross Production Efficiency)
58
What are some strategies for Exploitation Efficiency (game of hide and seek)?
1. strategies for detecting prey
2. strategies for capturing prey once detected
3. counter strategies to avoid detection in the first place
4. counter strategies to frustrate capture if detected
Avoid encounters (vertically migrate) or avoid detection (be transparent) and frustrate capture (have spines or be very large or very small).
59
What is the Diel Vertical Migration (Avoid Detection)?
The zooplankton community migrates up to the surface ocean at night to feed in the dark while avoiding visual predators like small fish.
During the day they migrate down to the safety of the darkness found at depth.
60
What is Exploitation Efficiency in Spring Blooms in Temperate North Atlantic Region?
Exploitation Efficiency is very low (10%). The phytoplankton not found by grazers (copepods) sink into the deep ocean as dead phytoplankton cells. Grazers enter diapause (hibernation) and become decoupled.
61
What is Exploitation Efficiency in Tropical Oceans/Environments?
Exploitation Efficiency is very high (90%). Almost all phytoplankton found and consumed by grazers.
62
What is Gross Growth (Production) Efficiency?
Amount of CONSUMER BIOMASS produced divided by amount of PREY INGESTED. This efficiency ranges between 20% and 60%.
63
What is Trophic Transfer Efficiency a function of?
```
Exploitation Efficiency (10% to 90% )
Gross Production Efficiency (20% to 60%)
```
64
What is the combined effect range of both exploitation and gross production efficiencies (Exploitation + Gross Production)?
An overall trophic transfer efficiency of about 10% to 20%
65
Suppose you had phytoplankton productions of 1000 biomass units per year and you had a food chain with 3 trophic steps between phytoplankton and fish that you wanted to catch each year?
phytoplankton (1000) --> zooplankton (100) --> small fish (10) --> your fish (1)
How much fish production would you expect each year if tropic transfer efficiency is 10% for each trophic step?
D) 1 biomass units of fish per year
66
Why are marine food chains strongly size-structured?
You can guess who-eats-who based on the size of the organisms.
67
Is the number of trophic levels between phytoplankton and harvestable fish smaller or bigger in high nutrient regions?
```
Smaller in high nutrient regions such as coastal upwelling regions.
Open Ocean (7 trophic levels)
Continental Shelf (4 trophic levels)
Upwelling Regions (3 trophic levels)
```
68
Open Ocean Province
Low primary productivity per square meter. Area extent is large, so overall primary production is high. Small phytoplankton leads to large number of trophic steps (7 total) and loss of (up to 1/10)^7=1/10,000,000 to get to harvestable fish. Does not make up overall primary production and produces small fish production.
69
Upwelling Province
High primary productivity per square meter. Area extent is small, so overall primary production is low. Large phytoplankton leads to small number of trophic steps (2 total) and loss of (up to 1/10)^2=1/100. Does make up small overall primary production and produce large fish production.
70
Why study marine microbes?
Proportion of living biomass in the global ocean. Bacteria and unicellular eukaryotes have high biomass.
71
What is oligotrophic?
Pelagic environment (water column) that has naturally very low plant nutrient concentrations. The vast subtropical gyres are oligotrophic
72
What is eutrophic?
Pelagic environment (water column) that has naturally high plant nutrient concentrations. The coastal upwelling zones are eutrophic.
73
What is the Traditional Food Chain Concept?
Organisms are in a given Trophic Level depending on whether they produce chlorophyll or not (Autotrophs vs. Heterotrophs) and on the organism’s size.
74
What is the source of carbon and energy for heterotrophic bacterial growth?
Heterotrophic bacteria grow on dissolved organic matter released from phytoplankton by steady leakage. It could also be released from cell senescence or sloppy feeding by zooplankton.
75
Discovery of an Important New Bacteria-Sized Autotroph
Sallie Chrisholm and others discovered a new autotroph in oligotrophic regions using analytical flow cytometry. This important new autotroph is called Prochlorococcus.
76
What is the New View (1990's) of Marine Food Webs?
It recognizes the importance of Prochlorococcus.
77
Where does growth advantage go to in oligotrophic (low nutrient) open-ocean environments?
The growth advantage goes to the smallest phytoplankton cells called Prochlorococcus.
78
What should we know about Prochlorococcus?
Prochlorococcus is an autotrophic bacterium, which contains chlorophyll and is the smallest type of phytoplankton.
1. Main primary producer in oligotrophic (low nutrient) environments.
2. Responsible for more than a quarter of global ocean primary production.
79
What should we know about heterotrophic bacteria?
Heterotrophic bacteria are highly abundant in all ocean environments.
Heterotrophic bacteria consumes dissolved organic carbon from large phytoplankton cells. Protozoans and heterotrophic bacteria cause the organic carbon to respire back to carbon dioxide.
80
What forms are most of the biomass in the open-ocean?
Heterotrophic bacteria and Prochlorococcus
81
Recall: What is the importance of the global ocean primary production?
It is the component of the global ocean cycle. It is important to our understanding of global climate and ability to predict future global climate change.
82
What is an efficient biological carbon pump?
Large dominant phytoplankton cells have large dominant grazers, which means large fecal material sinks to the deep ocean with organic carbon.
83
What is an inefficient biological pump?
Small dominant phytoplankton cells have small dominant grazers, which means small fecal material cannot sink and the particulate organic carbon is respired back to CO2.
84
What is the expected efficiency of the Biological Carbon
| Pump for Costal Upwelling Zones?
A) The carbon pump is very efficient in coastal upwelling zones
85
What happens to growth advantage when nutrient concentration is reduced?
The growth advantage shifts to small phytoplankton cells.
86
What happens to carbon when small phytoplankton cells are found at low nutrient concentrations?
Carbon is NOT efficiently pumped into the deep ocean.
87
What happens to carbon when large phytoplankton cells are found at high nutrient concentrations?
Carbon is efficiently pumped into the deep ocean.
88
What is the simplified pelagic food chain conceptualization?
From bottom to top
1. Primary Producers (Phytoplankton)
2. 1st Consumers
3. 2nd Consumers
4. 3rd Consumers
5. 4th Consumers
89
What is Vertical Zonation?
Communities are divided into distinct bands, or zones, at characteristic heights in the intertidal.
Species are not randomly distributed throughout the intertidal zone, but rather are arranged within relatively narrow vertical ranges.
90
What are physical stresses and their stress factors?
Physical stressors set upper limit to species distributions.
Stress Factors:
1. Desiccation
2. Temperature
3. Food Availability
4. Wave Energy
5. Salinity
6. Dissolved Oxygen
91
What are biological interactions and their factors?
Biological interactions set lower limit to species distributions.
Biological Factors:
1. Competition for Space
2. Predation
92
Species diversity within a Rocky Intertidal Community depend on
1. Intermediate Disturbance
| 2. Keystone Predators
93
What is Physical Disturbance?
Regulate species diversity within a community and open up gaps or patches in rocky intertidal.
94
What is the Intermediate Disturbance Hypothesis?
Disturbance maximizes species diversity by removing dominant species and allowing less competitive species to form themselves again.
Too much disturbance keeps the rock bare with few species. Too little disturbance allows the dominant competitor for space to take over and form a monoculture (single species).
95
What are Keystone Species?
Species that have effects on their communities that
are proportionately much greater than their abundance.
A rocky intertidal starfish called Pisaster is an example of keystone predator.
Massive die off of starfish along US West Coast.
96
What is Trophic Cascade (Sea Otter-Kelp Forest Example)?
1. Sea Otters eat sea urchins
2. Sea urchins are herbivores that eat
tiny young kelp (before they grow large).
3. Removal of sea otters allows sea urchins to grow to high abundance
4. Low abundance of sea otters leads to high abundance of sea urchins and low abundance of kelp forests
97
How long is the process of building a calcium carbonate reef structure?
It is a very slow process: < 1 mm per year to about 20 mm per year.
98
How are coral reefs formed?
1. A new island forms (mantle hot spot or ocean-ocean plate collision) and a fringing reef develops in shallow sunlit waters close to shore of the island.
2. The island slowly sinks with age (crust cools and thins) and at the same time the coral slowly grows upward by secreting its calcium carbonate support structure layer by-layer, forming a barrier reef.
3. Later in time the entire island is submerged
and all that is left is the reef - referred to now as coral atoll.
99
What is a Zooxanthellae?
Zooxanthellae are chlorophyll-containing algal
symbionts that live in the tissue of the coral polyp.
Corals receive 60- 90% of their overall nutrition from
photosynthetic-derived products!!!
100
What species do corals compete against for space?
Corals compete with other corals and with macroalgae.
101
What happens when corals compete with macroalgae?
The competitive advantage is shifted in favor of macroalgae when nutrients from agricultural activities run off the coast and onto coral reefs.
102
What is Coral Bleaching?
1. It is the zooxanthellae algae that give corals all of their beautiful natural colors.
2. Coral bleaching is the name where corals expel their symbiotic zooxanthellae algae due to environmental stress such as unusually warm water.
3. Corals can recover and regain their zooxanthellae if the stress is small or short-lived (a couple of weeks).
4. Coral death follows if the stress is extreme and/or prolonged.
103
Why are corals extremely sensitive to increases in ocean temperature?
Just 1 degrees Celsius above normal temperatures for a period of a few weeks leads to coral beaching.
104
2015-2016 El Nino Warming Effect Disastrous for Coral Reefs
Temporary warming events are super imposed on human caused multidecadal warming, increasing devastating effects on coral reef mortality.
105
How much was the Great Barrier Reef bleached?
Half of the Great Barrier Reef Has Been Bleached to Death Since 2016
106
What is the modeled onset of annual severe bleaching under Business as Usual emissions scenario?
1. Red regions will see regular beaching by 2030 (less than 15 years)
2. Orange and Yellow regions indicate onset of regular bleaching by 2040 (about 25 years)
3. Blue regions have until 2050-2060 (about 35 to 45 years)
4. Note: COP-21 Pledges will add an additional 10 years onto the onset dates above, but will not prevent severe annual bleaching from occurring…
107
What causes Ocean Acidification?
1. Increases in CO2 in the atmosphere leads to increases in ocean acidity
2. Projected Increases in ocean acidity lead to slowing of calcium carbonate precipitation and/or eventually coral dissolution
3. An atmosphere above 480 ppm is Expected to Enhance Coral Loss - We are now at 406ppm
4. Note that Twice PreIndustrial Atmospheric CO2 = 550 ppm
108
What is the expected scenario of reef changes with increasing atmospheric CO2?
375 ppm: +1 degrees Celsius
450-500 ppm: +2 degrees Celsius
>500 ppm: +3 degrees Celsius
The atmospheric CO2 concentration is currently at 406 ppm and going up by 2-ppm to 3-ppm each year - so it will reach 450 in about 20 years.
109
What is the expected scenario for coral reef survival with 1.5 degrees Celsius vs. 2 degrees Celsius global warming?
1. Coral reefs will decline by 70-90% in a 1.5ºC world
| 2. Virtually all (>99%) coral reefs will be lost in a 2ºC world
110
What is a Pakicetus?
A Pakicetus is a hoofed animal that looked like a dog/wolf with hoofed feet and long, thick tail. It lived 53 million years ago (after dinosaur age). It is classified as earliest whale.
The special ear bone feature is identified for cetaceans and found in no other species.
111
What are Mysticetes and Ondocetes?
Mysticetes are Baleen whales (filter-feeders), while Ondocetes are toothed whales.
112
What is the Pacific Humpback Migration?
1. Summer Feeding at high latitudes with long day length and lots of biological productivity
2. Winter Calving at low latitudes - usually warm, but low or no food
113
What are the differences in vocalization between Odontocetes and Mysticetes?
Odontocetes (toothed whales)
1. Produce rapid bursts of clicks and whistles
2. Single clicks are generally used for echolocation
3. Collections of clicks and whistles are used for communication.
Mysticetes (baleen whales)
1. Often make the long, low-frequency, sounds known as the whale song.
114
What is Mysticete Vocalization?
Complex and haunting sounds used in sexual selection and simple sounds may be used in navigation.
115
What are the sources of anthropogenic sound in the ocean?
1. Commercial Shipping - Engine and Propeller Noise
2. Naval Operations -Low Frequency Active Sonar
3. Oil Exploration - Seismic Surveys with Explosive Air Guns/Cannons
* Repeated Every Ten Seconds, 24 hours a day, For Days and Weeks at a Time
116
How do spectograms visualize the whale vocalization?
1. Time on the x-axis
2. Frequency on the y-axis
3. Loudness is denoted by Brighter Colors
117
What is Ambient Ship Noise?
It has Low Boat Traffic and High Boat Traffic
118
Why was the International Whaling Commission (IWC) set up?
It was set up by the terms of the International Convention for the Regulation of Whaling (ICRW) to make decisions on quota levels on the findings from the Scientific Committee of the IWC.
The members of the IWC voted on 23 July 1982 to apply a moratorium to all commercial whaling beginning in 1985.
119
Why does Japan whale?
Japan whales now for scientific purposes. The numbers are close to 1,000 Minke (not-endangered), 50 Fin
(endangered), 50 Humpback (endangered) and 5 Sperm (endangered) whales each year.
NOTE: The IWC found the Japanese research to be unnecessary, and that the same ends could be
accomplished by non-lethal methods, but Japan continues this practice.
120
Why does Norway whale?
Norway registered an objection/reservation when the 1982 IWC whaling moratium was signed. Norway resumed domestic commercial whaling and objected against the moratorium in 1993. They now take about 600
Minke (not-endangered) whales each year.
121
Why does Iceland whale?
Iceland whales for scientific purposes and issued licenses in October 2006. Iceland has an exemption to the moratorium through reservation in 2002. They take about 150 Fin (endangered) and 200 Minke (notendangered)
whales each year.
122
What is the molecular structure of water?
Water is a highly polar molecule with non-bonding electrons, two hydrogen molecules with polar covalent bonds, and an oxygen molecule.
123
What are H-bonds?
H-bonds are relatively weak bond energy holding adjacent water molecules together with unchanging strength.
124
What is thermal (kinetic) energy?
Thermal/kinetic energy pushes/breaks adjacent molecules apart and increases with increasing temperature.
125
What is Latent Heat of Fusion?
The amount of heat required to convert 1 gram of solid ice to liquid water(80 calories per gram) --> phase change
126
What is Specific Heat Capacity?
The amount of heat energy required to raise 1 gram of liquid water by one degree celsius (1 calorie per gram per deg C). This is among the highest of any substance on earth. --> raise the temperature
127
What is Latent Heat of Vaporization?
The amount of heat energy required to convert 1 gram of liquid water to water vapor (540 calories per gram).
1 calorie = 4.184 Joules
128
What is an important consequence of water's high specific heat capacity?
2. 93% of the excess heat energy trapped by greenhouse gas build-up since the industrial era has been taken up by the ocean.
4. In other words — you owe the ocean a big thank you for greatly attenuating the magnitude of global warming!
129
What is Evaporation in regard to latent heat?
Latent Heat removed from the ocean and stored in the
| atmosphere in the form of water vapor.
130
What is Condensation in regards to latent heat?
Latent Heat released into the atmosphere as sensible heat by condensation of water vapor (to form clouds and rain).
131
What are the molecular properties of water?
1. Strong polar nature of the water molecule makes it a very good solvent for ionic constituents (salt ions) (ex: it can dissolve a lot of salt)
2. Hydrogen bonds are weak, but below 100 degrees C they are strong enough to allow water molecules to bond temporarily with other water molecules to form liquid water. Below 0 degrees C, they are strong enough to hold/lock all water molecules into solid crystalline ice.
3. High specific heat capacity means a given heat addition does not change ocean temperatures as much as would occur if the same amount of heat was added to the atmosphere (or land).
4. High latent heat of vaporization allows large amounts of heat to be removed from the ocean, stored at latent heat in the form of water vapor and then transported by winds to other parts of planet where it can then be released to the atmosphere as sensible heat upon precipitation.
132
What is salinity?
Salinity is a measure of salt concentration (total weight of salt) in a seawater sample. It is the number of grams of salt contained in a thousand grams of seawater and expressed as parts per thousand and denoted by
the symbol ‰.
Ex: 35 grams of salt in 1000 grams of seawater has a salinity of 35‰.
A more modern unit of salinity is used in official oceanographic research called the “practical
salinity unit” (psu), that is based on electrical conductivity measurements rather than the mass of salt
measurements. Both methods give essentially the same numerical values (i.e., 35‰ 35 psu).
133
What is the variation in surface salinity?
1. All salinities in the ocean (deep ocean included!) are/were set at the air-sea interface.
2. Evaporation at the ocean surface removes only freshwater and leaves behind salt - thus increasing surface ocean salinity,
3. Atmospheric precipitation adds freshwater to the surface ocean - thus reducing surface ocean salinity.
4. Overall, salinity is a direct function of evaporation minus precipitation.
134
What happens to the relative proportion of ions?
The relative proportion of ions making up the salt mass remains unchanged everywhere in the ocean.
135
What is Idealized Hadley Circulation?
High SLP at North Pole and 30 degrees North.
Low SLP at 60 degrees North and Equator.
Rain around the equator and 60 degrees.
1. Moist surface air at the equator warms and rises aloft. Air aloft spreads north/south and becomes more dense as it cools and dries (due to precipitation) and then sinks at about 30° latitude.
2. Dry air aloft descends and warms and spreads out over the sea surface at 30° to the north and south. The surface air picks up moisture and by 60° latitude it has warmed and moistened to the point where it rises, cools, precipitates and spreads out aloft north/south.
3. Near the poles the dry air aloft becomes very cold and very dense so it sinks over the poles and spreads out toward the equator.
136
What is Annual Average Precipitation Pattern?
Hadley circulation produces upward convection and high precipitation along the equator and also at about 60° Latitude.
137
What is Annual Average Evaporation Pattern?
Hadley circulation at around 30° latitude is where cold dry air aloft descends and warms and spreads out
north/south (and is turned by Coriolis) over the earth’s surface.
The warm and dry surface winds are conducive to strong evaporation in the subtropics regions centered at 30 degrees latitude.
138
What is Atlantic Ocean Salinity?
Once removed from the surface the salinity remains constant unless it mixes with other water masses.
139
Surface Salinity Variation
1. Surface salinity varies widely and is a function of evaporation minus precipitation
1) High latitudes have low surface salinity
• High precipitation
• Low evaporation
2) Tropics have high surface salinity
• High evaporation
• Low precipitation
3) Equator has a dip in surface salinity
• High precipitation offsets high evaporation
2. While salinity may vary considerably in different regions, the relative proportion of one
ion to another does not vary.
140
What are the non-conservative seawater constituents?
Nutrients, oxygen, carbon dioxide
1. Sources
2. Sinks
3. Transports
4. Chemical Reactions
141
What are non-conservative constituents: plant nutrients?
1. Low in surface layer because of rapid uptake by phytoplankton in the presence of sunlight.
2. High at depth because of respiration/remineralization and no uptake by phytoplankton in the dark.
Sink through phytoplankton uptake & source through bacterial remineralization
142
What are non-conservative constituents: dissolved O2?
In mixed layer, photosynthesis produces O2.
In deep water, respiration consumes O2.
Little respiration occurs at depth due to low organics
needed to fuel O2 consumption combined with horizontal
advection of high O2 water from other locations.
Source through phytoplankton photosynthesis …and air-sea diffusion & sink through bacterial respiration
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What would make the oxygen minimum zone lower?
Global warming is expected to increase the strength of the thermocline and reduce vertical mixing and diffusion across this boundary.
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What is Weak Thermocline (Today)?
It is relatively easy mixing and diffusion (thick red arrow) of oxygen down into the oxygen minimum zone and thereby moderate extent of the minimum.
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What is Strong Thermocline (Future)?
It is relatively difficult mixing and diffusion (thin red
arrow) of oxygen down into the oxygen minimum
zone and thereby enhance the extent of the minimum.
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What is the observed de-oxygenation of global ocean?
1. Previous ocean models predict a global O2 inventory decline of 1-7% by 2100.
2. Direct observations recently published show a global O2 decline of 2% since 1960. Some regions exceed 4% decline.
3. Declines of a few percent are potentially
detrimental to marine ecosystems.
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What is the Conveyor Belt Circulation?
Warm less salty shallow current
| Cold salty deep current
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What are non-conservative constituents: CO2?
Photosynthesis takes up (consumes) some CO2 to make organic carbon and thereby lowers CO2 in the upper ocean.
Below the euphotic zone (the sun lit zone of surface ocean) the respiration by bacteria that
degrade dead organic carbon produces CO2 and thereby increases CO2 at depth.
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What are the sink and source for CO2?
Sink: Phytoplankton Photosynthesis Consumes CO2 in the surface ocean to form particulate organic carbon.
Source: Microbial Respiration Produces CO2
in the deep ocean.
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What is the largest active/mobile reservoir of carbon dioxide?
Carbon dioxide in the deep ocean (below the thermocline).
151
What causes CO2 to flux out of the ocean?
Bringing deep ocean water that is rich in CO2 into contact with the atmosphere.
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What does coastal upwelling bring?
It brings deep water that is cold and rich in CO2 (more acidic) up to the surface in coastal regions.
153
Ocean Acidification Part 1
1. The ocean has taken up 30% of all the CO2 we have emitted since the start of the industrial era — so you owe a big-big thank you to the ocean!
2. But this has come at a cost: Acidity has increased by 26%.
3. The ability of the ocean to take up more CO2 in the future will go down with increases in acidity
4. Cold waters take up more CO2 and so high latitude regions are acidifying faster than lower latitudes — polar seas are at great risk!
5. Coastal upwelling bring CO2 rich water (i.e., already pretty acidic) to the surface and with surface water now more acidic than before the net effect is for upwelling regions to be highly vulnerable to acidification.
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Ocean Acidification Part 2
1. With business as usual rates of CO2 emissions ocean acidity will increase by 170% by the end of the century
2. Within decades polar oceans will be corrosive to unprotected calcareous shells of marine organisms
3. Within decades tropical coral reef growth will be hampered or stopped altogether.
4. The far-reaching effects of ocean acidification are predicted to impact food webs
5. People who rely on the ocean’s ecosystem services are especially vulnerable and may need to adapt or cope with ocean acidification impacts within decades.
6. Big changes are expected in economically important upwelling regions
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Marine Chemistry Conclusion
1. The field of chemical oceanography is concerned with the geochemical (global-scale elemental) cycles that take place at least in part within the ocean.
2. A main approach to identifying geochemical cycles is to identify a particular element’s principal sources into the ocean, its major avenues of transport removal from the ocean and any significant chemical reactions that it participates in while in the ocean.
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Conclusion Part 1
1. Conservative Properties (temperature and salinity) do not change value once the water leaves the surface ocean (except when different water masses mix together at great depth)
2. Non-Conservative Properties (nitrate, phosphate, oxygen, carbon dioxide) can change value after the water leaves the surface ocean.
3. The Conveyor Belt Circulation explains why nitrate and phosphate get more concentrated as the deep water moves from the Deep North Atlantic and gradually into the Deep Pacific - organic matter rains down into
the deep water, and it is remineralized to nitrate and phosphate, as the deep water slowly moves toward the Pacific.
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Conclusion Part 2
1. Oxygen in the deep ocean become lower as the deep circulation slowly carries water from the North Atlantic to the Pacific because the remineralization process,
that caused nitrate and phosphate to increase along the way, consumes oxygen.
2. Carbon Dioxide that enters the ocean by diffusion across the air-sea interface, or from biological respiration, undergoes a chemical reaction with water to form
other inorganic carbon compounds (e.g., carbonate and bicarbonate) and this reaction needs to be considered when examining the overall cycling of carbon
dioxide in the ocean - for this class, the details of the reactions are not important, just knowing that other reactions need to be considered is enough - you do,
however, need to know that increases in CO2 leads to more acidic ocean
3. Sinking organic carbon and biogenic/mineral precipitation produces a strong vertical gradient of CO2 in the ocean.
158
What is the history of the term El Nino?
The original definition of El Niño goes back to 18th or 19th century when Peruvian sailors coined the term to describe a warm southward current that appeared annually near Christmas time off the Peruvian coast. Hence the name El Niño = Spanish for “The Child” = “Christ Child".
159
What is Walker Circulation (East-West Atmospheric Circulation Cell)?
1. Winds at the ocean surface move toward the equator, but are deflected by Coriolis toward the (right) west to form surface trade winds.
2. Winds aloft move away from the equator, but are deflected by Coriolis toward the (right) east to complete the Walker-Circulation.
Sir Gilbert Walker discovered that this east/west atmospheric circulation cell periodically reverses direction!
160
What is the Southern Oscillation?
The Southern Oscillation is the Periodic Reversal of the Walker Circulation Cell.
Low SLP and High SLP of Trade Winds - Normal Conditions
High SLP and Low SLP of Trade Winds - El Nino Conditions (reversed)
La Nina Conditions - exceptionally strong Trade Winds
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What is El Nino Southern Oscillation (ENSO) Coupled Ocean-Atmospheric Interactions?
In 1969 Jacob Bjerknes proposed that there was a physical connection between the oceanographic and atmospheric variations and now the oceanic (El Nino) and the atmospheric (Southern Oscillation) aspects are often combined in the single term 'El Niño Southern Oscillation' (ENSO) that encompasses both the ocean and the
atmosphere.
1. Roughly periodic (3-7 years) occurrence of prolonged (ca. 8 months) warming of coastal waters off of Peru and Ecuador
2. Coherent change in the east-west atmospheric circulation cell over the Pacific (Walker Cell) resulting in coherent changes in atmospheric pressure patterns,
precipitation patterns and wind direction
3. And Much Much More…
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What are the Sea Surface Temperature Patterns during La Nina?
Exceptionally Strong Trade Winds, Equatorial Upwelling and Cooling in the Eastern Pacific
163
What are the Sea Surface Temperature Patterns during Normal?
Normal Trade Winds, Upwelling and Cooling in the Eastern Pacific
164
What are the Sea Surface Temperature Patterns during El Nino?
Exceptionally Weak or Reversed Trade Winds, Little or No
| Equatorial Upwelling and Strong Warming in the Eastern Pacific
165
What should happen to global-average temperature when the thick warm pool of water in the western Pacific spreads out across a large area of the equatorial Pacific during an El Nino period?
A) Global Temperature Should: Go Up
The Correct Answer is (a) temperatures will go up as the
area of warm water in contact with the atmosphere increases and allows the ocean to give up some of its stored heat to the atmosphere.
166
What is the current status of El Nino?
El Niño conditions are developing across the Pacific Ocean, with meteorologists now putting the probability of a full event developing by the end of the year at almost 75 percent.
167
What are other natural climate variations that can temporarily warm and cool the earth?
1. El Nino Southern Oscillation (ENSO)
2. North Atlantic Oscillation (NAO)
3. Atlantic Multi-Decadal Oscillation (AMO)
4. Pacific Decadal Oscillation (PDO)
5. Arctic Oscillation (AO)
But in All Cases they are Superimposed on a Very large
Multi-Decadal Trend that IS human-caused global warming.
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Why is Human-Caused Global Warming a Multi-Decadal Trend?
The temporary warming and cooling effects of natural
climate oscillations are superimposed on a very large multi-decadal warming trend that represents human-caused global warming signal.
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Summary of El Nino
1. Besides El Nino Southern Oscillation (ENSO) there are a large number of other natural climate oscillations that change phase (sea surface temperature pattern and wind velocity pattern) on the order of decades
2. When examining the issue of global warming, one needs to take into account natural climate variability that can occur on the order of decades!
3. Global Warming is a Multi-Decadal Trend with natural decadal oscillations superimposed on that trend!
170
What is happening to atmospheric CO2 concentration?
Atmospheric CO2 concentration is increasing by about 2 to 3 ppm each year. So in just 20 years it will be about 450 ppm.
171
Global Temperature Anomalies Since the Industrial Era
| 1.0 °C Rise in Global Average Temperature
1. Limiting global warming to 2°C above pre-industrial levels is the accepted upper limit of warming expressed by the international community. And limiting warming 1.5 °C is the preferred level we aspire to attain.
2. During the the last ice age there was one kilometer of ice laying on top of Ithaca and global average
temperatures were just 4 °C colder.
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Putting Things Into Perspective
```
Present CO2 (406 ppm)
Inter-Glacial CO2 (280 ppm)
Glacial CO2 (180 ppm)
```
For 800,000 years orbital variations (Milankovitch Forcing) has altered ocean circulation that, in turn, allowed CO2 to move between the deep ocean and the atmosphere that then caused glacial and interglacial cycles.
The best that orbital variations could do is drive atmospheric CO2 up to 280 ppm. Humans, however, have driven CO2 to 406 ppm - humans are now more powerful than the orbital variations at drove our past ice ages!
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Natural Ocean-Atmosphere Oscillations
Numerous Naturally Occurring Ocean-Atmosphere Oscillations Can Temporarily Raise or Lower Global Average Temperatures on Time Scales of Year and up to a Decade or Two.
1. El Nino Southern Oscillation
2. Pacific Decadal Oscillation
3. North Atlantic Oscillation
4. Atlantic Multi-Decadal Oscillation
5. Arctic Oscillation
The multiyear and multi-decadal natural climate
oscillations are averaged out and the underling
global warming tend (blue line) is revealed.
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What is human forcing compared to?
Human Forcing Through Addition of CO2, CH4,
N20 is Much Larger Than Natural Forcing Components at
Decade Time Scales.
175
What is the strong evidence for human cause?
1. If we account only for natural forcing (solar & volcanos etc…) in climate models, we are not able to
recreate the observed increase in global temperature.
2. Only by also accounting for both natural forcing
and CO2 from fossil-fuel burning and
deforestation to the model are we able to
recreate the observed temperature increases
since the industrial era.
3. The fact that dozens of different numerical models
used by different groups of scientists around the
world get basically the same answer for their
numerical experiments provides strong evidence
that humans are responsible for the increase in
global temperature observed since the industrial.
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IPCC 5th Assessment Report (AR5)
1. The fact the the earth has warmed significantly since the industrial era is Unambiguous
2. The fact that humans are largely responsible for the observed warming is Extremely Likely (i.e., 95% certain)
Antidotally: we are now more certain of human caused global warming than we are that smoking causes cancer!
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What is the response of the ocean to global warming?
Sea Level Rise
178
Sea Level Rise Since the Beginning of the Industrial Era
1. There has already been a 20cm (about 8 inches) rise above preindustrial era levels
2. The Rise is Accelerating
3. IPCC* 5 report that came out abouta 5 years ago placed the expected rise to 1 meter above pre-industrial
level by the end of this century…
4. More recent estimates put the end of century sea level rise at 8 feet…
179
What are the contributions to sea level rise?
Roughly half of the current sea-level increase is due to thermal expansion and the other half is due to melting land ice.
180
Populations and Assets at risk to a 1-meter sea level rise at the end of this century…
Tens of millions of people
| Ten of trillions of dollars in assets
181
What would happen to sea levels at 2 degrees Celsius?
In a 2 degrees Celsius world future generations will have to deal with sea levels of 40 to 70 feet higher than at present.
182
What is the response of the ocean to global warming?
Arctic Ice Loss
183
Observed Global Warming is Not Evenly Distributed Over the Earth
Polar Regions are Especially Sensitive Due to Loss of Albedo Effect
184
When is the arctic largely to be ice free?
The arctic is expected to be largely ice free in
| the summer by 2035.
185
What are the two issues in the arctic?
1. Vast oil reserves under the sea floor of the arctic.
| 2. Shipping lanes between US East Coast or Western Europe and all of Asia.
186
How Much Longer Can We Keep
| Emitting CO2?
Not Much Longer!
187
The Paris COP-21 Climate Talks…
| Leaders of essentially all the nations on earth signed a final statement containing these key points
1. To maintain stable human societies we must prevent the earth from warming above 2 ºC relative to
the pre-industrial level.
-To stay below 2 ºC warming we must take the global energy system to net zero carbon emissions by mid-century - the whole planet!!!
2. For the survival of a many island nations we aspire to prevent the earth from warming above 1.5 ºC relative to the pre-industrial level.
-To reach this goal we would have begin immediately and reduce by half in 12 years and to zero by mid-century.
3. BTW— Voluntary national pledges made under the Paris pact to cut CO2 emissions, if fulfilled,
would yield a 3 ºC world at best.
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This Generation’s Unique Place in the Full
| Arc of Human History…
Because the CO2 we put into the atmosphere (minus 50% removed by land and ocean) stays in the atmosphere for 10,000 years (forever essentially), there has always been a fixed limit to the total amount of CO2 that can be emitted before we cross the 1.5C and 2.0C warming thresholds.
We started approaching that limit the very first day we began clearing forests for farming and burning fossil carbon for energy. And the rate of approach of this limit has accelerated with time.
Past generations have brought us to brink of a critical decision point in human history with little room/time for indecision.
It turns out that are the generation that will decide if humanity will cross these warming thresholds — and once crossed,
there is no going back!
Our decision to cross or not cross the limit will affect the lives of all people on earth for the next 10,000 years -
basically for the rest of human history. This is the fate our generation is called upon to face…
189
This Special Generation…
1. Every so often a generation is called upon to rise to greatness. In 1940 a generation was asked to rise up and fight a world war.
2. This generation is now being called upon to rise to an even greater challenge - to decarbonize that planet in two decades to save all of humanity.
3. We can be small and shrink back and say it is too complex or it will cost too much or we can seize this moment to be truly great.
4. As President Obama said, “we are the first generation to fully understand the threat of climate change and we are the last generation that has a chance to fix the
problem”
5. It really is a matter of now or never - and all of it has to take place within the next two decades!
190
We currently have technologies that are economically
| viable to deploy…
Numerous agencies and NGOs such as, The International Energy Agency, Stanford University, The United Nations, Google have undertaken separate analyses addressing the feasibility of transitioning to clean energy.
- they all come to the same conclusion: 100% global transition to clean energy is possible — both technically and economically
- the only barriers that exist are social and political (leadership).
And since you get to decide the leaders, it is up to YOU!
191
Cornell's Climate Action 2035 Plan
Campus Energy Infrastructure
192
The coming years will test all of us…
1. Of all the generations that have ever existed on this
earth, it falls on this generation to decide if we cross the
1.5 ºC or 2.0 ºC warming thresholds.
2. Every so often a generation is called upon to rise up and do something extraordinary.
-This generation is called upon to rise up and rapidly
decarbonize the global energy system by mid-century
3. If we succeed in this effort, our generation will be
celebrated by future generations for the next 10,000
years!
