APS124 Pheonix 2 Flashcards
On average, as well as getting hotter, the planet is getting…
drier
What are 3 things an organism can do if the climate changes in its environment?
- Move (migrate) - stay in climate envelope via migration (range shift) - most migration so far has occured upslope rather than latitudinally
- Adapt - plastic and evolutionary responses have occurred - plasticity is rapid, but has limts - evolution will struggle to keep pace with rapid climate change
- Die - plenty of evidence that this is happening in response to climate change
Average species (764 species in different taxonomic groups) latitudinal shift is…
- 9km per decade
- greater in regions of greater warming
- shifts generally keep pace with climate, i.e. expected = observed
In the santa rosa mountains, elevation of the dominant plant species rose by … between 1977 to 2006/2007
~65m
Climate velocity is…
the speed you need to move to keep pace with climate change
The global mean climate velocity is..
0.42km yr-1
… regions have low climate velocity
mountainous
Climate velocities are fastest for .. biomes such as…
flat,
deserts, mangroves, flooded grasslands and savannas
High temperature and drought are likely to reduce..
NPP (net primary productivity - carbon gain)
In 2003 (heatwave) there was a … reduction in gross primary productivity across europe, which cancelled out 4 years of net ecosystem carbon …
30%,
sequestration
More evapotranspiration is positively correlated with..
higher annual productivity
(so is precipitation but that also includes factors such as runoff which cause a curved, rather than straight, line correlation)
Forests cover … of the land’s surface
~30%
Populations rely on forest for
- timber
- food
- medicines
- watershed protection
- recreation
- aesthetic value
- spiritual benefit
C sequestration can lead to
negative climate feedback
Trees…
grow slowly but can die quickly
There is increasing tree … in all continents except antarctica, for obvious reasons
mortality
In more drought-adapted forest, mortality is higher during … drought, whereas in less drought-adapted foresr, mortality is higher during … … drought
longer,
short-term seasonal
NDVI is
Normalised Difference Vegetation Index
- leaf cover or greenness or photosynthetic capacity
- used to estimate ecosystem productivity
- 1982 onwards
- Can be used to assess growing season length
NPP is
Net Primary Productivity:
- the net carbon uptake by vegetation
(photosynthesis - respiration)
Satellite data can be used to assess inter-annual variability in productivity, which gives a good idea of..
current sensitivity of ecosystems to climate variation
Seddon et al. (2016) said ecosystem (vegetation productivity requires warmth, water and light, and therefore the key climate change drivers are therefore:
- Air temperature
- Water availability
- Cloud cover
What did Seddon et al. study?
Compared changes in productivity (satellite) with air T, water and cloud data over past 14 years
Vegetation sensitivity index:
How responsive productivity was to inter-annual climate variability
- more sensitive in cooler environments (improved productivity)
- arid systems are very unsensitive
Rubisco is more efficient at…
greater CO2 as there’s less photorespiration
About 23% of photosynthesis is
C4 photosynthesis (with CO2 concentrating mechanism) - so less sensitive to changes in environmental CO2
FACE experiments:
Free Air CO2 Enrichment experiments
- Average crop yield stimulation of 17% (lower than previous estimates)
- Wheat and rice did not respond to elevated CO2
Warming climate also increases rate of..
respiration - more carbon loss
… of the world’s surface is ocean
71%
… of earth’s habitable volume is marine
> 99%
Water is liquid at…
unusually high temperatures and over a wide range of temperatures (0-100C)
Life depends entirely on…
liquid water
Maximum density of water is at … so there is usually…
~4C
liquid water below ice
Sound carries…
very well in water
At 20C, sound travels…
> 4 times faster in water
Approx … salt per 1000g seawater
35g
Salinity is measured in…
practical salinity units (psu), with 35psu very similar to 3.5%