Chapter 29-30 Flashcards
Limnology
investigation of aquatic systems within continental boundaries, including glaciers, groundwater, rivers, streams, and wetlands (freshwater)
who are primary producers in aquatic environments
- Autotrophic organisms that fix CO2, providing organic carbon
- In streams and lakes, macroscopic algae and terrestrial runoff provide organic carbon
what is the effect of eutrophication?
- Usually from N and P accumulation
- Can lead to harmful algal blooms, oxygen dead zones, and fish death
- Caused by runoff from terrestrial environments
what are Harmful Algal Blooms (HAB)?
Red tide—water becomes red or pink from growth of pigmented algae.
cHABs – cyanobacterial toxic blooms
* Can kill fish or marine mammals
How do different HABs effect fish?
Red tide- Brevetoxin build up in animals from the algae and they die
cHABs- cyanobacteria produce Microcystin which can get into drinking water and cause liver failure
what is an estuary?
tidal mixing between freshwater and saltwater
-microbes must be halotolerant (can withstand large changes in salinity)
- water is calm and nutrient rich
- nurseries for juvenile fish
- can have pollution killing macroscopic life
- results in BLOOMS
Photic zone
Upper 100 meters of the open ocean
- Diverse collection of microbes
Phytoplankton
major source of organic matter in the
open ocean
- picoplankton
nutrient levels extremely low
dissolved organic matter (DOM)
consumed by Heterotrophic microbes and are released by resident microbes.
* Can be sugars, proteins, lipids
Photosynthate
product of photosynthesis
Particulate organic matter (POM)
microbial cells, insoluble detritus, and other solid organic material
What is the microbial loop?
Key to survival in the photic zone its the tight recycling of nutrients, rather than allowing them to sink to the seafloor
open ocean N cycling
Open ocean limited by nitrogen
- Anammox reaction— reduction of NH4 to N2
- denitrification
- Four N2 fixation sources:
* Richelia intracellularis
* Genus Trichodesmium
* Crocosphaera watsonii
* Cyanobacterium (UCYN-A)
SAR11
are the most abundant organisms
on Earth.
- 25-50% of the microbial cells in the coastal and open ocean
Prochlorococcus
the most abundant and smallest cyanobacteria on Earth
- Responsible for ~5% oxygen production on Earth
-very large pan-genome
ecotype
genomic adaptations that confer environment type
amount of microbes in the open ocean
- Viruses are the most abundant by count
- Bacteria and Archaea are most abundant by mass
what is the role of viruses in the microbial loop?
catalyze the movement of nutrients from organisms to DOM and POM pools
where is the largest microbial biomass in the ocean?
Piezosphere- Depths with pressure above 100 atm
cold (<5 Celsius)- Psychrophilic and
psychrotrophic
subglacial lake microbes
-Diverse S cycling genes present
-Evidence for methanogenesis and methane oxidation
-Diverse N cycling genes present
Dominant metabolism types:
Chemolithoautotrophy
Chemoorganoheterotrophy
what is important about soil?
-store and release carbon
-hold nutrients thatmgrow food
-Purify water
-Are home to diverse communities
Mineral soil
Contains less than 20% organic carbon.
- Most of Earth’s soils are in this category
Organic soil
Possesses at least 20% organic carbon
Nitrogen in soil
Often considered in the soil carbon content as carbon to nitrogen ratio (C/N ratio)
- Agricultural soils have ratios above 30 and are nitrogen limited.
- This is why nitrogen fertilizer is added
