Environmental Science Quiz | Applied Climate Change, Ocean Acidification and Ecosystem Questions

Earth's surface emits part of the energy it receives as infrared radiation. Greenhouse gases absorb particular infrared wavelengths and re-emit energy in all directions, including back toward the surface. This keeps the lower atmosphere and surface warmer than they would otherwise be. It is distinct from the ozone layer's absorption of ultraviolet radiation.

Weather describes short-term atmospheric conditions at a particular time and place, whereas climate describes averages and variability over decades. Daily variability can produce cold days even during a long-term warming trend, so one day cannot disprove the 30-year pattern. Likewise, one hot day alone cannot prove climate change.

Whether an area is a carbon sink or source depends on the difference between inputs and outputs over the same period and boundary. Uptake is 100 units, while release is 70 + 40 = 110 units, so 10 net units move to the atmosphere. A forest is not automatically a sink; fire, respiration and decomposition must be included in the budget.

Floating ice already displaces water equal to its weight, so melting it causes little direct change in A's water level. B represents glaciers and ice sheets on land: meltwater is newly added to the ocean, raising the level. In the real world, thermal expansion of warming seawater also contributes to global mean sea-level rise.

Dissolved carbon dioxide increases hydrogen ions and lowers seawater pH. Hydrogen ions react with carbonate ions, reducing the carbonate available for calcium-carbonate shells and skeletons. Ocean acidification means a decline in pH relative to the previous condition; seawater does not have to fall below pH 7 for acidification to occur.

Excess nitrogen and phosphorus can drive an algal bloom. When the algae die, microbial respiration during decomposition consumes dissolved oxygen, particularly in deep water that mixes poorly. The nutrients do not directly erase oxygen atoms; the critical mechanism is the biological sequence of growth, death and decomposition.

When a substance accumulates in organisms and is difficult to metabolize or excrete, predators can acquire it from many prey organisms. Its concentration may therefore rise at successively higher trophic levels, a process called biomagnification. The stepwise pattern fits this process, although not every chemical biomagnifies in the same way.

Being non-native is not the same as being invasive. B was introduced outside its native range, spread rapidly and caused both displacement of native species and economic loss, so it fits the invasive-species criteria. A is non-native, but the information reports no harm, so non-native status alone is insufficient to classify it as invasive.

Habitat fragmentation can restrict movement to food, shelter and mates and can reduce exchange between populations. In this case, higher movement and mate-finding in B are consistent with improved connectivity. However, corridor effectiveness depends on the species, width, placement and safety; it is not guaranteed to be identical for every organism.

Bright sea ice has a high reflectivity, whereas dark ocean water absorbs more solar energy. When ice loss exposes water, increased absorption and warming can promote additional melting, creating a positive feedback that amplifies the initial change. Here, positive means self-reinforcing, not beneficial.