L25

Question 1

horizon levels of soil

Answer 1

• differ in soil chracteristics
• influence microbial activity

top layer: O layer- not quite soil yet, undecomposed plant materials

A layer- organic material, surface soil (high in organic matter), dark in colour, microbial activity high, uses rehizosphere + water

B layer- subsoil (contains minerals + humus, little organic matter and microbial activity)

C layer- bed rock, develops directly from underlying bedrock

Question 2

explain melioidosis

Answer 2

• saprophytic gram neg. bacili
  -causes sepsis + pneumonia
• high case fatility rates
  -resistant to many antibiotics
• incidences/severity linked to rainfall + weather

Question 3

what defines environmental boundaries of a disease

Answer 3

• water
• general nutrient deficiency
• less acidic soilds
• various element concs. which reflect poor fertility
  -characteristics of the micro ecology
• plant associations, particularly grass like plants