The graph shows changes in average annual ocean salinity and temperature with depth.

Referring to the graph:

(i) describe how ocean salinity varies with depth;

(ii) describe how ocean temperature varies with depth.

Explain three economic benefits of mangrove swamps.

To what extent have the management strategies adopted to resolve human pressures on one named coastline been successful?

(i)

Award up to [2] for any two points, provided at least one point has been quantified.

• Ocean salinity is lower nearer the surface (around 32.5 ppt) [1].
• Salinity increases very slowly in the top 100 m of ocean [1].
• Between 100 m and around 750 m ocean salinity increases quite rapidly (from 32.5 ppt to over 34 ppt) [1].
• From 750 m to about 1500 m ocean salinity increases slowly (from over 34 ppt to less than 35 ppt) [1].

(ii)

Award up to [2] for any two points, provided at least one point has been quantified.

• Temperature is highest nearer the surface (13–15°C) [1].
• Temperature is fairly constant in the top layer of water (to about 100 m) [1].
• Temperature decreases rapidly from about 100 m to 250 m (from about 13–15°C down to about 5°C) [1].
• Below 250 m temperature decreases slowly [1].

Award [1] for each economic benefit and a further [1] for development/exemplification.

Mangrove swamps provide many economic benefits, including:

• food, especially fish such as shrimp – these form the basis of a fishing industry
• fuel – the wood can be burnt for fuel
• building material – the wood can be used for fencing/housing
• protection against hurricanes/tsunamis – reduces losses/reconstruction costs
• high levels of biodiversity – unique wetland environment so ecotourism
• some species are used for medicines – eg for skin disorders, sores and for throat cancer; this has indirect economic benefits
• reduced costs for environmental clean-up agencies by absorbing nutrients from farming and sewage disposal.

For example:
Mangrove swamps support a fishing industry [1] because they provide a breeding ground for fish [1].

There are many different pressures in coastal areas: tourism and recreation; fishing; transport; energy developments; conservation; settlement; trade; industrial development; water abstraction; sand mining etc. These pressures tend to lead to conflicts over management strategies.

Conflict may be small-scale eg between dog walkers and families on Studland Beach, or between fisher folk and conservationists in Soufriere, St Lucia. It may also be large-scale, eg the proposed coal mining and transport of coal via the Great Barrier Reef, Australia.

Coastal management strategies include land-use zoning; coastal protection schemes; managed retreat; conservation areas; coastal reclamation; hard and soft engineering schemes; user fees; seasonal; establishment of management bodies; preparation of information materials (such as notice boards); inclusion of all stakeholders.

Good candidates may recognize that it is not possible to resolve conflicts/please all stakeholders but a good strategy may involve compromise that different parties can live with, eg aesthetically pleasing defences. Also, conflicts may become more common and therefore harder to resolve as tourism grows, technology develops and land-based activities put more pressure on the coastal
zone. There may be conflicts within stakeholder groups, eg some fishermen are mainly subsistence whereas others are commercially orientated.

An alternative approach might be to compare management strategies on two coastlines in order to assess their relative success.

At band D expect a description of coastal management strategies for a named coastline.

At band E expect either an explanation of coastal management strategies or an attempt to evaluate the relative success of named coastal management schemes in resolving conflicting pressures.

At band F expect both.

Marks should be allocated according to the markbands.

Many candidates struggled with reading the graph. Many could not get beyond simple description regarding increase/decrease and rarely used sufficient quantification.

This was generally well answered, showing good understanding of the benefits of mangrove swamps; although sometimes not well developed.

Although there were some strong responses, this question often caused significant problems. The question focused on resolving conflicting human pressures on a coastline. However, a limited range of management strategies was recognized. Most candidates simply described a selection of hard and soft engineering strategies, with little focus on human pressures, and little evaluation of their effectiveness.