Particulate Matter & Trace Elements Flashcards
What are the 3 groups of elements used when using Al to normalise Bulk Inorganic Chemical Compositions? (With example of the type of components associated with each)
- Metal/Al constant with depth (Terrigenous components)
- Metal/Al decreasing with depth (Biogenous components)
- Metal/Al increasing with depth (Scavenged elements)
Why is the North Pacific used over the Atlantic when looking at Trace Elements?
It is at the end of the nutrient push, there are no river inputs and it is overall more stable than the Atlantic
What is the distribution of Scavenged Elements and give examples of these elements?
Concentrations decrease with depth.
Al, Pb, Mn, Th and Co
3 Methods of measuring Particulate Matter in the ocean
- Pinger-Electronic System
- Filter with 0.45 um pore size
- Sediment Traps
5 Sources of Particulate Matter
- Suspended matter carried by rivers
- Airborne (Aeolian) dust
- Cosmic Dust
- Biological Particles (debris, plankton, zooplankton)
- Coastal Sources
What is Marine Snow?
A combination of biological debris
6 Sources of Biological Debris
- Phytoplankton
- Zooplankton
- Faecal Matter
- Shell Debris
- Fish
- Waste Products
What is the overall distribution of suspended matter in the oceans?
Not uniform, depends where and when you are, productivity is seasonal and particles are driven by productivity, particles that make it to the seabed become part of the sedimentary record
4 Points about the Particulate Matter profile
- Maximum at the Surface
- Minimum in the middle of the water column
- Maximum at Depth
- Temporal and Spatial differences
What does Nepheloid mean?
Particle concentration at the bottom of the oceans. There is more on the Western side of the Atlantic due to the conveyor belt and bottom currents
What affects the settling speeds of particles?
Size and density
In the North Atlantic what time of year shows rapid deposition and an increase in biological debris?
July and August
Why do temporal changes occur and why are they important?
Because chemistry and biology of the oceans is strongly influenced by the processes in the surface waters, there are also strong seasonal pushes of phyto-detritus to the seafloor from the euphoric zone, linking the benthic organisms in the surface waters to the deep waters
What are gross chemical changes?
Short bursts of of rapid POM transport associated with productivity events control the composition of the settling particles, resulting in changes in chemical characteristics throughout the water column
What does POM stand for?
Particular Organic Matter
What are labile compounds?
Munch-able compounds that are utilised before reaching the seafloor
What are refractory compounds?
Resistant compounds - moe likely to reach the seafloor
Give some information of munch able stuff in the oceans!
Re-suspension and/or lateral advection of POM impacts the benthic boundary layer in terms of quality and quantity of POM arriving at the sediment surface
What does BBL stand for?
Benthic Boundary Layer
What is the Porcupine Abyssalplain (PAP)?
Found in the NE Atlantic and is characterised by strong seasonal fluxes of POM related to primary productivity cycles in the overlong eutrophic surface waters
What is the faecal pellet express?
The descending of marine snow throughout the water column
What controls the distribution of trace elements?
Rates of supply and removal, chemical speciation and the presence of nutrients
Why are correlations used when looking at trace elements?
High correlations provide evidence for the incorporation of travel elements into the biogenic parts containing nutrients
Which elements together are an indicator of hard skeletons?
Zn and Ni with Si
Which elements together are an indicator of soft skeletons?
Cd with P
Why does Manganese have multiple sources in the ocean?
Because of Hydrothermal Vents (especially black smokers)
What happens if waters are anoxic?
Minor elements such as Fe and Mn are more soluble in reducing conditions
How do the ocean and atmosphere systems link?
Much of the trace element demand by plankton may be supplied by dust, if trace elements limit plankton then dust controls plankton which controls the biological pump, which also impacts atmospheric levels of CO2
What does a lack of dissolved Fe mean?
Populations of marine algae will be lower than normal
What percentage of the worlds oceans has a Fe deficiency?
40%
