Nutrients and trace elements

Nós do fluxograma

• Nutrients and minor elements 

• Non-conservative elements concentration change due to addition or removal processes 

• Abundance and residence times removal reflected in low concentrations and short residence times - as they are corrlated minor elements - intermediate levels, high variability trace elements - trace levels, shortest RTs 

• Removal processes- adsorption -biological up take remove dissolved substances and add this material to the particulate phase. subsequent settling leads to removal from water column via sedimentation dependent on partlcle size - larger = faster 

• Adsorption most important for traced metals positive ions are attracted to the surface of partical and binds to it, then it is removed via sinking and more are added as it sinks = decreasing ions with depth 

• scavenger- type depth profiles highest levels near surface amd dcreasing levels with increasing depth 

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• Biological uptakes Determins depth profile of nuitrients they are taken up in euphotic zone into the algal biomass. detritus sinks from the zone into the deep - no nutrient uptake below euphotic zone. however bacterial breakdown realses nutirents at depth and recycles them 

• the two layered ocean there is a vertical segregration of processes - thermocline- prevents diff temperature water mixingnutrient cycling - uptake in mixed surface layer -transder of deriral biomass from top to bottom - gradual microbial degradation of biomass - release nutrients at depth also recycling via up welling 

• Nutrient type depth profiles controlled by uptake and regeneration 

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• Nutrient-type elements classification by biological requirements -macronutrients - these are required in large amounts and are structural components of phytoplankton so can all limit growth -micronutrients - these are required in small amounts and used in enzymes or photosynthetic apparatus they are also called - recycled elements- biolimiting elements 

• Bio-limiting trace metal profiles Zn -near zero levels nar surface but highest in deep water depth duration similiar to that of nitrate zinc is used for enzyme carbonic anhydrase - uptake of carbon dioxide Fe essential for phtosynthetic apparatus, nitrate uptake and nitrogen fixing it is supplied by aeolian transport - limitation may limit phytoplankton growth in remote open ocean areas with little duct deposition 

• conservative type depth profiles concentration only varies with salinity - ratio of element over salinty constant depth 

• Depth profiles 

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