Scientists at a coastal research station have drawn Fig. 1 to show changes affecting a coral reef near Zanzibar. Warmer sea water has caused coral bleaching...
Question 1 Report
Scientists at a coastal research station have drawn Fig. 1 to show changes affecting a coral reef near Zanzibar. Warmer sea water has caused coral bleaching, while a nearby mangrove area has been cut back for tourist boats. The diagram links the reef, seagrass, mangroves and a fishing village. Fishers report smaller catches and the village has experienced more wave damage during storms. The research station is asking whether protecting connected ecosystems is a better response to climate change than concentrating only on the coral reef. Refer to Fig. 1.
(a) Identify the ecosystem shown in Fig. 1 that can reduce wave energy before it reaches the village. [4]
(b) Describe two ways in which mangroves and seagrass support fish populations. [6]
(c) State four possible effects of coral bleaching on the fishing village. [8]
(d) Explain why management of the mangroves, seagrass and reef should be linked in this coastal area. [12]
Answer Details
(a) Mangroves reduce wave energy before it reaches the village. Their roots and trunks obstruct waves, slow them and protect the shore. [4]
(b) Mangroves provide sheltered nursery areas and root hiding places from predators. Seagrass provides food and habitat. Both ecosystems support juvenile fish and improve water quality by trapping sediment, so healthier habitats can support more fish. [6]
(c) Bleaching occurs when corals expel their symbiotic algae and lose colour. Coral growth may slow or corals may die, reducing reef habitat. Fish numbers and diversity can fall, causing lower catches, lower fishing income and poorer food security. Tourism income may decline, and reduced reef protection can increase storm-wave damage. Any eight valid effects gain credit. [8]
(d) Mangroves trap sediment before it reaches reefs, keeping water clearer for coral growth. Seagrass stabilises seabed sediment and connects mangrove nursery habitat with reef feeding habitat; fish use several ecosystems during their life cycle. Reefs support fisheries and break wave energy offshore, while mangroves also reduce wave energy. Together they lower erosion and flood risk. Warming can bleach coral, so reducing local stresses such as sediment and boat damage improves resilience. Integrated protection supports livelihoods, biodiversity and adaptation to climate change. [12]
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