10. (a) The figure below shows the relative sizes of a lemming population (histogram or bars) and the percentage phosphorus in forage (curve) over a number of years - Leaving Cert Biology - Question 10 - 2006

Phosphorus is a vital nutrient that supports plant growth, which in turn increases the availability of forage for lemmings. Higher phosphorus levels result in more nutritious and abundant food sources, leading to improved health and reproductive success in lemmings. This relationship demonstrates the ecological importance of nutrient cycles in supporting wildlife populations.

To survey the lemming population, I began by selecting a matched ecosystem in a designated study area. I used capture and release methods, tagging individual lemmings to monitor their numbers. I recorded sightings over multiple sessions, documenting their presence at different locations within the studied area, and used various statistical methods to calculate population density.

Pollution refers to the introduction of harmful substances or contaminants into the environment, which can negatively affect ecosystems, living organisms, and human health. It can come from various sources including industrial waste, agricultural runoff, and urban development.

One significant pollutant from agricultural origin is nitrate, which can leach into water bodies from fertilizers. High levels of nitrate can lead to eutrophication, resulting in excessive algae growth that depletes oxygen levels in water, harming aquatic life and disrupting ecosystems.

One way to control nitrate pollution is through the implementation of buffer zones with vegetation along waterways. These buffers can absorb nitrates before they enter the water system, effectively reducing the amount of this pollutant.

The disposal of waste poses several issues, including land pollution, water contamination, and negative impacts on wildlife. To minimize waste, one effective strategy is to promote recycling programs that encourage the reuse of materials. Another approach is to implement waste reduction initiatives that focus on consumer education about minimizing packaging and food waste.