week 2

• sea is salty due to dissolved salts from rivers and rocks
• practical salinity scale -> unites measure of salinity (compared against standard KCl)
• k+ shows conservative behaviour
• Phosphate inputs from hydrothermal vents are ignored (so true residence time for phosphates are longer)
• K (removal constant) measures the rate of geochemical reactivity
• the primary control of phytoplankton activity is nutrient availability
• N and P in soft tissues is most intensively recycled in the upper thermocline
• The upper thermocline is the transition layer in a body of water, typically the ocean, where the temperature decreases rapidly with depth. It lies between the mixed surface layer and the deeper, more stable water layers.
• bacterial recycling of organic matter helps to maintain dissolved nutrient levels in deeper waters
• photosynthesis dominates uptake of nutrients by photoplankton in surface water