GEO 103 Exam 3 Dimova

What are the four characteristics of a living organism?

Capture, store, and transmit energy; Reproduce; Adapt to environment; Change over time.

What are the three main domains of life?

Bacteria, archaea, and eukarya.

What is the main function of bacteria in the ocean and can they be seen with the naked eye?

They decompose dead organic material and return it to the ocean as nutrients; they cannot be seen with the naked eye.

Give examples of single-celled and multi-celled eukaryotic organisms.

Single-celled: picoplankton like Ostreococcus; Multi-celled: copepods, humans, and marine mammals.

What is the difference between autotrophs and heterotrophs?

Autotrophs make their own food through photosynthesis or chemosynthesis from inorganic sources, while heterotrophs must eat other organisms or their remains.

Is chlorophyll an organism or a chemical compound?

It is a chemical compound.

What is the chemical equation for photosynthesis and where does it occur in the ocean?

6CO2 + 6H2O -> C6H12O6 + 6O2; It occurs in the upper water column (photic zone) because it requires sunlight.

What is the chemical equation for respiration and where does it occur in the ocean?

C6H12O6 + 6O2 -> 6H2O + 6CO2 + energy; It occurs everywhere because all organisms must respire to release chemical energy.

What is primary productivity?

The amount of inorganic carbon fixed by autotrophs into organic compounds.

How is primary productivity measured?

Timed weighing of autotrophs, timed weighing of inorganic carbon uptake, and space colorimetry.

What is space colorimetry and how does it work?

Satellites measure ocean color from space; high primary activity represents green light due to chlorophyll, which satellites track.

Which earth ecosystem is the most productive per unit area?

Estuaries and swamps.

Which areas within the ocean are the most productive and why?

Continental margins, equatorial divergences, and Antarctic divergences; they feature upwelling, vertical mixing, and river/dust inputs that supply nutrients.

Which areas within the ocean are the least productive and why?

Interiors of subtropical gyres (ocean deserts); the water prevents vertical mixing from bringing nutrients to the surface due to a stable pycnocline.

Name three photosynthetic organisms (autotrophs).

Seaweeds, diatoms, and cyanobacteria.

How is water transparency measured in the ocean?

Using a Secchi Disk or a Turbidity meter.

What are the two types of organisms based on the biozone they occupy?

Benthic (attached to sea floor) and Pelagic (free-floating).

How are organisms divided based on light penetration?

Into the photic (lit) zone and the aphotic (dark) zone.

What is the difference between the photic and aphotic zones?

The photic zone is lit by sunlight (first 200m), while the aphotic zone is in complete darkness where only respiration occurs.

What is plankton and what are some examples?

Drifting or weakly swimming organisms suspended in the water column; examples include phytoplankton, copepods, and jellyfish.

Why are plankton essential to the marine food chain?

They form the absolute base of the marine food chain, without which no higher animals could survive.

Why are coral reef systems highly productive despite living in nutrient-poor waters?

Corals concentrate nutrients by living symbiotically with algae.

How do corals recycle nutrients?

Corals respire and digest organic matter, recycling nutrients directly back to the algae inside them.

Why are coral systems highly sensitive to water temperatures?

High temperatures cause stress, resulting in the expulsion of their algae, a process known as coral bleaching.

What distinguishes corals from jellyfish?

While they have similar feeding methods, corals secrete hard Calcium Carbonate (CaCO3) cups for protection.

What provides the color of a coral?

Algae living within the coral tissues.

What is the symbiotic relationship between coral polyps and algae?

Algae perform photosynthesis and provide food to the coral, while the coral provides nutrients to the algae.

Why do corals prefer nutrient-poor waters?

Low nutrients prevent rapid algae growth, which reduces food competition for the coral.

What happens to corals if there is an excess of nutrients in the water?

Algae grow rapidly and outcompete the coral.

Why is clear water important for corals?

Clear water allows sunlight to penetrate deep enough to support photosynthesis.

What is a coral bleaching event?

The loss of algae from coral due to a loss of pigmentation, typically caused by warming oceans, which starves the coral.

Where are the largest coral communities found?

In warm, tropical parts of the ocean.

Why do corals grow from the bottom up?

They grow upwards toward the light to compete for space and light, similar to trees in a rainforest.

How do coral communities shape continental margins?

They build up massive limestone (CaCO3) structures.

What type of volcano is the original setup for creating coral reefs?

Hot spot volcanoes.

What are two reasons for the recent decline in ocean coral health?

Warmer oceans, over-nutrification, sedimentation, careless tourism, and coral mining.

How is climate defined?

The average weather in a region over a period of at least 30 years.

What is negative feedback in climate systems?

A process that counteracts an initial change.

What is positive feedback in climate systems?

A process that enhances an initial change.

Which three parameters do scientists monitor to record climate change?

Temperature, extent of ice coverage, and biodiversity.

What is proxy data in climate science?

Indirect evidence from natural climate recorders used to determine past conditions.

How do tree rings indicate past climate?

Trees grow faster during wet years and slower during dry years, which is represented in the thickness of the rings.

What does the sediment stratigraphic method reveal?

The type of sediment deposited reflects historical sea-level and climate shifts at a specific location.

What is the biostratigraphic method?

The study of specific species' fossils to indicate particular geologic timeframes.

What does the oxygen stable isotope method measure?

The ratio of light to heavy oxygen isotopes in samples, which correlates to historical temperatures.

What is isotopic fractionation?

The separation of light and heavy isotopes during physical state changes, such as evaporating and freezing.

Why is isotopic fractionation larger during cold climates?

Low temperatures lack the energy to mobilize both isotopes, whereas high temperatures have enough energy to mobilize both.

What is the greenhouse effect?

Atmospheric gases allow incoming short-wavelength sunlight to pass through but trap outgoing long-wavelength heat radiating from Earth.

What is the most potent greenhouse gas in nature?

Water vapor (H2O).

What is the role of dust in climate change?

It can block incoming sunlight and cool the Earth.

What are the three leading natural causes of climate change?

Milankovitch cycles (variations in Earth's orbit), volcanic eruptions, and the movement of Earth's plates.

What is the primary human-induced cause of climate change?

The burning of fossil fuels.

How does high atmospheric CO2 affect ocean chemistry?

It causes ocean pH to decrease, leading to acidification.

What is the biological pump?

The ocean's mechanism for reducing CO2 by pumping it from surface waters to deep waters through marine snow and burying organic material in sediments.