Environmental Science Test 4

How does the thermocline influence the seasonal patterns of nutrient primary productivity?

with more nutrients, there is more NPP in aquatic systems in the spring and summer than in the fall and winter.

FACE experiments

(Duke university) Free Air CO2 Enrichment; measures effects of CO2 enrichment on ecosystems NPP under ambient and enriched CO2→ all positive % change with enriched CO2 but amount changes

GCM: General Circulation Models / Global Circulation Models

Most complex model ever developed by humans look at all of the aspects of the earth's system, such as ocean currents and land surface processeshorizontal is latitude and longitude, vertical is height or pressure

omnivore

A consumer that eats both plants and animals

carnivore

A consumer that eats only animals (meat).

herbivore

A consumer that eats only plants.

chlorophyll

A green pigment found in the chloroplasts of plants, algae, and some bacteria

Need to offset the loss of water through transpiration with the uptake of water through roots

Assumes that there is sufficient water in the soil to replace that water lost by the plant through transpiration

how have the above two factors functioned to change the global carbon cycle?

Addition of 7 gigaton a year from fossil fuels & 2 gigaton from deforestation are put back into the cycle

Role of thermocline in limiting the uptake of CO2 by oceans

Although there is a transfer of carbon in the form of dead organic matter from the surface waters to the deeper waters of the oceans, the thermocline imposes a major limitation on the transfer of carbon from the surface into the deep waters of the ocean. As surface waters cool, the thermocline breaks down and vertical mixing occurs. The mixing brings nutrients from the deep waters to the surface. However, in the deep ocean waters(2000+m), this zone of mixing is restricted to the surface waters (75-300m)

primary producer

An autotroph, usually a photosynthetic organism.

What has been the general trend in atmospheric concentrations of CO2 over Earth's history (past 4 billion years)?

Atmospheric concentration of CO2 has declined over Earth's history shows that the removal of CO2 from the chemical weathering of rocks has been much greater than the rate of CO2 release from volcanic activity

diurnal and seasonal cycles of atmospheric CO2

CO2 concentrations are highest at night and early morning when plant respiration dominates (values decline over the day as CO2 is taken up in photosynthesis); winter has almost no photosynthesis occurring, during summer there is lots of photosynthesis taking place

Historical trends in atmospheric CO2 since the Industrial Revolution (past 150-300 years)

Changes in atmospheric CO2 concentrations have increased by over 45% since pre-industrial times

Changes in global average land - ocean surface temperature over the past century (since 1880)

Consistent increase in global annual surface temperature anomalies (same for ocean surface temperatures)

influence of equatorial upwelling on ocean productivity

Creates a zone right along the equatorial region that is unusually high in NPP because of the warmth and movement of nutrients; brings nutrients up from the depths

method for determining past atmospheric concentrations of CO2

Data prior to direct observations are estimated from various techniques, including the analysis of air trapped in antarctic ice sheets

global warming and changes in ocean circulation

Decline in sea ice cover in arctic, melting of Greenland ice sheet→ Fresh water input Reduced sinking because northern oceans have become less saline therefore less dense Conveyor weakens→ slows down the transport of warmer waters to the Northern atlantic

Major factor(s) controlling the uptake of CO2 by the oceans?

Diffusion of CO2 into the water

volcanoes and subduction as mechanisms for the exchange of carbon between the geosphere and atmosphere

Eventually they get subducted (drawn down) deep into the earth's crust where temperatures are high enough to cause calcium carbonate to undergo a metamorphosis in CaSiO3 rock, these rocks then eventually comeback to surface through volcanoes and CaSiO3 rocks will eventually be lifted to earth's surface where it is weather thus completing the cycle.

trend in average sea surface temperatures over the past 50 years

General increase in temperatures similar to land(.45F increase in mean annual tropical sea surface temperatures)

Trends in extreme temperatures over the past 50 years

Generally increasing for hot extremes in their temperature and frequency while cold frequency decreased

geographic pattern of surplus/deficit in annual average net radiation balance

Generally we have a surplus around the equator and tropics and a deficit in the polar regions and higher latitudes

CO2 uptake in aquatic plants

In submerged aquatic plants, the CO2 diffuses directly across the leaf surface into the leaf interior

influence of increasing ocean acidity on marine organisms

Has a negative impact on the majority of marine species

general patterns of carbon storage in living vegetation and soils (as they relate to our discussion of global patterns of net primary and ecosystem productivity)

Higher soil organic carbon density in north towards poles; Higher biomass carbon density below equator

influence of temperature and precipitation on decomposition

Higher temperature = higher rate of decomposition & higher soil moisture = higher rate of decomposition

Leading contributors to rising atmospheric concentrations of CO2 as a result of: Burning of Fossil fuels Forest clearing/burning

In 2014, China Wass largest emissions producer at 25% of world emission while the US lead emissions per capita. Forest clearing/burning = large problem in South America & Africa (amazon region especially)

How does nutrient cycling differ in terrestrial and open-water (lakes and ocean) ecosystems?

In terrestrial ecosystems, the amount of carbon and nutrients in the living vegetation decreases as you move from the tropical forests to the temperature and boreal regions, while the amount of carbon and nutrients in the soil increases. Same basic story in ocean, but decoupling of decomposition and respiration.Coastal Upwelling causes more nutrient cycling around land masses and coasts, while open-water ecosystems produce very little productivity

influence of thermocline dynamics on patterns of aquatic productivity in tropical, temperate and polar regions?

In the tropics, you don't have a thermocline, so they're less productive than the cooler temperate waters, because no movement of nutrients. Exception right along the equator because of equatorial upwelling.

respiration

Inhalation and exhalation of air.

plant growth

Is a function of the net carbon uptake and allocation

Potential influence of rising atmospheric concentrations of CO2 on greenhouse effect and global energy balance.

Less heat escapes into space, we have more greenhouse gases, and more retained long-wave radiation; changing co2 can change the net radiation balance, leading to changes of surface temperature, etc.

global warming and feedbacks on surface albedo (reduction in snow/ice cover)

Loss of reflective ice cooling 'albedo' & replaced by dark ocean warming (same for snow and land)

Global carbon cycle - main reservoirs and fluxes (atmosphere, oceans, land, etc.)

Major reservoirs (in order from greatest to least): sedimentary rock is the largest, ocean, soil, atmosphere, organisms. Fluxes: Rate at which carbon flows from one reservoir to another.-Photosynthesis (CO2 from atmosphere transferred to plants)-Plant respiration (CO2 from plant to atmosphere)-Litterfall (Carbon from plant parts, branches, leaves, etc. fall back to the Earth and return carbon to soil)-Soil respiration (decomposition releases CO2 to be released to atmosphere)-Ocean (carbon is absorbed at released at the Earth's surface

Greenhouse effect

Natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases

secondary producer

Organisms that derive energy from consuming plant or animal tissue and breaking down assimilated carbon compounds. (heterotrophs)

chemical weathering as a mechanism for the exchange of carbon between the atmosphere and geosphere (role of CaCO3, H2CO3, & CaSiO3)

Over the lifetime of the earth, roughly 75% of all carbon in the atmosphere has found its way into deposits of calcium carbonate (limestone) deposits which constitute by far the largest reservoir in the carbon cycle. An important family of rocks in the earth's crust is made up of molecules in which calcium occurs in combination with silicon (CaSiO3). When these calcium silicate rocks weather, the silicon atoms in them combine with oxygen to form quartz-like (silicon dioxide, SiO2) minerals and the calcium ions become available to form limestone. Highest CaCO3 concentrations overlie tectonic boundaries. However, limestone deposits don't last forever. Eventually they get subducted (drawn down) deep into the earth's crust where temperatures are high enough to cause calcium carbonate to undergo a metamorphosis in CaSiO3 rock, these rocks then eventually comeback to surface through volcanoes and CaSiO3 rocks will eventually be lifted to earth's surface where it is weather thus completing the cycle.

trends in global average precipitation over the past century

Overall increase in mean global annual precipitation

patterns of ocean productivity

Photosynthesis (and therefore net primary productivity) restricted to surface light availability (decreases with increasing depth). Limited to the compensation depth. The primary factor controlling NPP in the ocean is nutrients of the surface waters. Largest net primary productivity at coasts vs deep waters

climate change and sea-level rise (past 18,000 years & past 150 years)

Sea level was over 100 meters lower than today at ice cover peak 18000 years ago. In last 150 years has risen at roughly 3mm/year

stomata

Small openings (pores) on the underside of a leaf through which oxygen and carbon dioxide can move

Oxygen cycle- Role of: Photolysis Photosynthesis

Stage-1: All green plants during the process of photosynthesis, release oxygen back into the atmosphere as a by-product. Stage-2: All aerobic organisms use free oxygen for respiration. Stage-3: Animals exhale Carbon dioxide back into the atmosphere which is again used by the plants during photosynthesis. Now oxygen is balanced within the atmosphere.

Processes controlling the exchange of CO2 between terrestrial ecosystems and the atmosphere

The diffusion of CO2from the outside air intothe leaf through the stomata is a function ofthe diffusion gradient (concentration of CO2in air - concentration in leaf). As the concentration of CO2in the atmosphere rises, the concentration gradient becomes greater and the flow rate of CO2 into the leaf increases.The increased uptake rate of CO2 gives rise to an increase in the rate of photosynthesis.

Net Primary Productivity (NPP)

The energy captured by producers in an ecosystem minus the energy producers respire

what processes lead to the period of elevated atmospheric O2 during the carboniferous period (250-450 million years ago)?

The first existence of terrestrial plant life that began photosynthesis as the primary process responsible for accumulation of O2 in atmosphere

how does the proportion of carbon that is contained in lignin-based compounds influence the rate of decomposition of plant litter?

The higher the rate of initial lignin content = slow decomposition rate

Influence of nutrient availability on NPP in aquatic ecosystems (lake and ocean)

The more nutrients and light available, NPP in aquatic ecosystems increases.

CO2 and ocean acidification

The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification

Role of ocean thermohaline circulation on the uptake of CO2 by oceans.

The only true process that is able to cause complete mixing, but occurs on a timescale of centuries

carbon allocation

The process in which plants allocate the net carbon gain to the production of new tissues

fate of carbon dioxide emissions - only a portion remaining in atmosphere

The rest go into the oceans and terrestrial ecosystems

global carbon cycle

The worldwide movement of carbon among terrestrial ecosystems, the oceans, and the atmosphere.

primary causes of past and recent sea-level rise

Thermal expansion: surface waters expand as they warm and the melting of the glaciers

how does the thermocline influence the seasonal patterns of nutrient availability in the surface waters?

Thermocline of summer months causes nutrient cycling to occur only in surface waters.In turnover (spring and fall) and in winter months, when the thermocline has broken down, vertical mixing occurs, bringing nutrients from deep water to surface Thus, low nutrients in summer months and high nutirients in winter High tempertures and light in summer months and low in winter months NPP spikes between transition from spring to summer

know how to interpret graphs that present the results of litterbug experiments (percent original mass remaining as a function of time)

WHAT WHAT WHAT?

what is the source of fossil fuels?

Vegetation dies and forms peat, peat is compressed b/t sediment layers to form lignite Further compression forms bituminous coal

Geographic patterns of atmospheric water vapor

Water vapor is the dominant greenhouse gas in the atmosphere, so low atmospheric water vapor in the polar regions increases the relative contribution of carbon dioxide to the "regional greenhouse effect"

CO2 fertilization effect (photosynthesis and plant growth)

an increase in the rate of photosynthesis (and plant growth) under elevated CO2

Autotroph

an organism that obtains food (carbon) without consuming other organisms. Generally utilize carbon dioxide as a source of carbon, using energy from the sun to convert CO2 (and other inorganic compounds) into organic compounds(primary producers)

Heterotroph

an organism that obtains food by easting other organisms or their by products (secondary producers)

influence of relative humidity on the rate of transpiration

as relative humidity increases the rate of transpiration decreases because the gradient becomes less steep

During which period(s) of the day should a greenhouse warming have the greatest relative effects of surface temperatures? (diurnal patterns of surface energy balance)

at night because there is almost no shortwave radiation and longwave is dominant (incoming solar radiation peaks around high noon. Outgoing radiationreaches its minimum around dawn.)

influence of light availability on the process (rate) of photosynthesis

availability has a direct and positive relation on the rate of photosynthesis

whole plant carbon balance

carbon uptake-carbon loss(function of the total plant mass) = net carbon uptake; environmental conditions that reduce the rate of photosynthesis will decrease the total carbon gain of the plant and therefore the rate of growth

food chain

diagram defining the relationship between different feeding groups (groups of organisms that derive their food resources in a similar manner)

processes controlling exchanges of carbon between oceans and atmosphere

diffusion; Warm tropical waters release gases; Colder waters from deeper below come up to the surface bc of upwelling, warm there, and release gases; Ocean is a source in the Eastern Pacific, where cold and deep water is upwelling, then warms up and releases part of its dissolved CO2; When surface currents lead water circulate towards the poles, surface waters cool down (including the Gulf Stream) and the net flux is going from the atmosphere to the ocean

influence of temperature variation on the rate of net photosynthesis (Tmin, Topt, Tmax)

direct effect on the rate; Tmin = minimum temperature below which photosynthesis will not occur (cold limit), Tmax = minimum temperature above which photsynthesis will not occur (hot limit), Topt = optimal temperature range for photosynthesis

long-term inorganic carbon cycle

emphasis on calcium carbonate (CaCO3, limestone), by far the largest of the carbon reservoirs. This cycle is linked to the carbonate-silicate cycle, supplying the calcium ions necessary for the formation of limestone.

long-term organic carbon cycle

emphasis on the formation and destruction of fossil fuels and other sediments containing organic carbon

short-term organic carbon cycle

emphasis on the interactions between the atmosphere and the biosphere: terrestrial (land) and marine (ocean) components

influence of annual precipitation and temperatures on NPP in terrestrial ecosystems

environmental conditions that reduce the rate of photosynthesis will decrease the total carbon gain of the plant and therefore the rate of plant growth. More precipitation = higher NPP (but slope begins to decrease for high values of precipitation) High mean annual temperature = high NPP (slope starts at almost 0 increases then plateaus off at high temps)

rubisco

enzyme that catalyzes the photosynthesis reaction (most abundant enzyme on earth)

Diffusion of CO2 from atmosphere into surface waters

generally taken up by primary producers but can also react with H20 to get HCO3-

net photosynthesis

gross photosynthesis - respiration

In which region(s) should a greenhouse warming have the greatest relative effects of surface temperatures?

high latitudes, specifically in northern hemisphere because it has more land than southern high latitudes ("regional greenhouse effect")

influence of (soil) water availability on rates of net photosynthesis

high water concentration in soil = high net photosynthesis and high stomatal conductance

nutrient cycling

how dead plants are reused by plants in a cyclical pattern

climate change and extreme weather events - hurricanes

hurricanes destructive power has increased around 70%. percent of hurricanes classified as category 4 or 5 has increased similarly

dependence of secondary productivity on primary productivity

increase in primary productivity increases secondary productivity; herbivores also constrain carnivore productivity

diffusion

is the tendency for particles of any kind to spread out spontaneously from where they are more concentrated to where they are less concentrated

transpiration

loss of water from the inside of the leaf to the atmosphere through the stomata

stomatal conductance (components)

number and opening of stomata, function of rate of transpiration

climate change and the decline of sea ice and glaciers

over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide

Future predictions: general global trends in average temperature and precipitation

overall predicted increase in temperature and precipitation wet areas will get wetter, dry areas will get dryeron average, we predict warmer and wetter planet, but some areas get cooler and some areas get dryer

global warming and feedbacks on melting of permafrost and increased decomposition

overall result in decrease in rate of decomposition therefore increase in CO2 increased atmospheric CO2 --> higher surface temperatures --> decreased permafrost --> increased decomposition --> increased atmospheric CO2 (continuous loop)

what processes have been responsible for the rise in atmospheric concentrations of oxygen(O2) over the past 2 billion years?

photolysis: whereby high energy ultraviolet radiation breaks down atmospheric water into component atoms (small role) photosynthesis is the primary process responsible for the accumulation of O2 in atmosphere

processes controlling exchanges of carbon between terrestrial ecosystems and atmosphere

photosynthesis and respiration

Influence of rising atmospheric CO2 on NPP in terrestrial ecosystems.

resulted in an elevated NPP

how does increasing greenhouse gases influence surface temperatures? (reduction of outgoing longwave radiation)

slows down surface temperature cooling so on average warms earth's surface

controls on the uptake of CO2 and loss of water through stomata

stomata can be expanded and shrunk

permafrost

subsurface layer of soil that remains frozen throughout the year (occurs in the high latitudes of Arctic and Antarctic regions)

Ecosystem

the biotic community and its abiotic environment functioning as a system

What factors led to the peak in the burial of organic matter during the Carboniferous period (250-450 million years ago)?

the first existence of terrestrial plants

influence of nitrogen availability on nitrogen uptake rate (by plant)

the greater the concentration of nitrogen in the soil, the greater the rate of nitrogen uptake by the plant roots

relationship between leaf nitrogen concentration and rate of net photosynthesis

the greater the nitrogen concentration, the greater the rate of net photosynthesis

IPCC Report - Cause of "recent" warming

the increase in anthropogenic greenhouse gas concentrations (aka increase in greenhouse gases caused by human activity); "very likely due" to human activity - strong statement

Major causes for the rise in atmospheric CO2 over the past 150 years

the mining and burning of fossil fuels & deforestation- slash&burn style clearing

photosynthesis

the process by which plants use light energy to make food molecules from carbon dioxide and water

During which season(s) should a greenhouse warming have the greatest relative effects of surface temperatures? (seasonal patterns of surface energy balance)

the winter

Future sea-level rise - primary causes

thermal expansion (of oceans) and melting of ice caps/glaciers, as a result of global warming and increased CO2 levels

consumer-decomposer

two major types of heterotrophs; consumers - an organism that obtains its energy by feeding on other organisms, decomposers - an organism that obtains energy from the breakdown of dead organic matter to more simple substances

photosynthetically active radiation (PAR)

wavelengths of light between 400 and 700 nm that photosynthetic organisms use as a source of energy