How can students in the photograph use the net to sample the invertebrates in the river.

Answer and Explanation:

Macroinvertebrate communities show spatial and temporal variability. Many taxons have more affinity for one specific type of habitat.

There are two principal sampling techniques. Qualitative and cuantitave. Qualitative techniques provide data about the river richness and the relationship between the different taxonomic group's abundance. They allow the obtention of the most representative and abundant taxons, estimates their densities, biomass, and calculates the diversity indexes for each sampling site by period. Nets are needed to sample.

Every possible microhabitat must be sampled. The use of the different sampling elements depends on the substrate.

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c

trachea, alveoli, lung capillaries, arteries