Outline one economic and one environmental benefit of coral reefs.

Explain the function of the oceanic conveyor belt(s).

Examine the economic effects of El Niño and/or La Niña events.

Economic benefits include a range of tourist activities, fish stocks/nurseries, coral sales, economic role as “nature’s flood defence” protecting coastal assets. Environmental benefits include maintaining biodiversity/habitats, role in marine food webs, carbon sink, environmental role in protecting coastlines.

In each case, award [1 mark] for identifying a valid benefit and [1 mark] for development or exemplification.

An overview of the OCB’s importance would be that it has a vital global role [1 mark] in regulating/moderating Earth’s ocean and atmospheric conditions (there are other ways of expressing this) [1 mark].

The remaining [4 marks] should be allocated for more detailed explanation either of the causes/functioning of OCB or a more detailed examination of its role in specific regions e.g. transferring heat/energy between the Pacific and Indian Oceans and the Atlantic Ocean. The North Atlantic is therefore warmer than the North Pacific, so there is likely to be more evaporation, condensation and precipitation there. There are other important regional effects too, notably cold counter-current returning to the equator, leading to localized cooling in equatorial waters. Some aspects of OCB are still not fully understood / science is contested, and good answers may reflect on this.

Also accept wider interpretation of importance for human settlement and activities e.g. mild maritime climate of NW Europe.

El Niño – along with La Niña – is officially defined as a sustained sea surface temperature anomaly across the central tropical Pacific Ocean. The mechanisms which cause these events are not well understood and are not expected to always be well-articulated in candidate responses. Some background explanation of the phenomenon may be useful in order to help explain the economic impacts.

There are both direct effects in the local zone of influence and knock-on effects in other places. There are both positives and negatives in both instances.

During normal (non-El Niño) conditions, at the ocean surface easterly trade winds move water and lower atmosphere air warmed by the sun towards the west. This also creates ocean upwelling off the coasts of Peru and Ecuador and brings nutrient-rich cold water to the surface, increasing fishing stocks.

El Niño events are associated with warm and very wet summers (December to February) along the coasts of northern Peru and Ecuador, with the economic costs of major flooding whenever the event is strong or extreme.

Further afield, El Niño events also result in drier conditions in parts of Southeast Asia and parts of Australia and the economic impacts of this, including bush fires, can also be addressed. Fewer tropical cyclones in western Pacific reduces disaster costs.

Changes to ocean currents can affect local fishing industries along affected coastlines (for instance, Peruvian anchovies may migrate south to Chilean waters).

La Niña events are essentially the opposite of El Niño events and are characterized by unusually cold ocean temperatures in the eastern equatorial Pacific. Rain on the western coasts of the Pacific is heavier than usual. Atlantic tropical cyclone activity is generally enhanced during La Niña events. Economic impacts of all of this may be explored although it is not necessary for full marks to be awarded.

Marks should be allocated according to the markbands.

Well answered with good exemplification in many cases. Others recognized the benefits but failed to develop their response sufficiently to gain a second mark.

This is obviously being taught well in most centres. To gain the full marks candidates needed to give a more detailed account of the functions globally or in specific regions. Many simply referred to surface currents and the transfer of heat and cold from warm to cool areas and vice versa, or focused on the distribution of nutrients.

This concept has been well taught. Good candidates were able to well exemplify economic benefits and costs on both sides of the Pacific.  There were some excellent maps showing normal and El Niño events. La Niña events were typically ignored. Weaker answers tended to be vague, unsubstantiated and lacking in place detail, or offered up pure descriptions with no attempt to modify or adapt to the question needs, focusing on social as well as economic effects.