Environmental response to tsunamis Kitty Currier, Sarah Sorensen, and Taylor Smith 11 March 2013

Environmental effects of tsunamis: Washover fans Gianfreda, F. et al. (2001) Impact of historical tsunamis on a sandy coastalb arrier: an example from the northern Gargano coast, southern Italy. Natural Hazards and Earth System Sciences 1: Foce Cauto washover fan (Italy), created around 493 BCE

Environmental effects of tsunamis: Washover fans Gianfreda, F. et al. (2001) Impact of historical tsunamis on a sandy coastalb arrier: an example from the northern Gargano coast, southern Italy. Natural Hazards and Earth System Sciences 1: Foce Cauto washover fan (Italy), created around 493 BCE

astjava/images/ej140.jpg Sumatra, Indonesia (Jan. 2005): 73 cm. thick sand deposit East Java, Indonesia (June 1994): rocky outcrop exposed Environmental effects of tsunamis: Sedimentation and erosion

copyright-e_siirila.jpg Environmental effects of tsunamis: Sedimentation on coral reefs

TongaTonga: coral limestone boulder; 10 m above sea level, ~130 m from present shoreline Environmental effects of tsunamis: Transportation of coral boulders

Ranonnga (Solomon Islands), after a magnitude 8.1 earthquake on April 2, Environmental effects of earthquakes: Tectonic uplift

5/images/Jan24_2005_lg/IMG_0935.jpg Environmental effects of earthquakes/tsunamis: Tectonic subsidence Sumatra, Indonesia, 2005

5/images/Jan24_2005_lg/IMG_0935.jpg Environmental effects of earthquakes/tsunamis: Tectonic subsidence & submergence & submergence Sumatra, Indonesia, 2005

eck_aceh_coral6m.jpg Environmental effects of earthquakes/tsunamis: Structural damage to coral efcheck_aceh_coral1m.jpg Sumatra, Indonesia, 2005

Indian Ocean tsunami (26 Dec. 2004) – “Coral reefs of the west coast of Thailand were minimally affected by the Indian Ocean tsunami of December 26, 2004…It is estimated that damaged sites will recover naturally in a time span of 5-10 years…” Phongsuwan, N., and B. Brown The influence of the Indian Ocean tsunami on coral reefs of Western Thailand, Andaman Sea, Indian Ocean. Atoll Research Bulletin 544: American Samoa tsunami (29 Sep. 2009) – “Much of the coral was broken or covered with sediments, and some of it died as a result. Both the run-up and run-down of the tsunami waves were very destructive. It will probably take years to decades for the reef to recover.” “UNSEEN DEVASTATION FROM TSUNAMIS CAN DESTROY CORAL REEFS.” 22 Nov Press release, Oregon State University Coral reefs and tsunamis

Effects of Tsunamis on Mangroves

Mangroves Woody plants Live along land-sea interface – Of bays, estuaries, lagoons, backwaters, and rivers – Upstream as far as water remains saline Circumtropical distribution High biodiversity habitat

Mangrove Habitat Provides a nursery and breeding ground Habitat for many species of epifauna and fauna – including bacteria, fungi, macroalgae, macrofauna, invertebrates, and other marine species Shoreline protection – sea from influences from land – land from ocean

Mangroves Excrete salt through foliage Roots mainly underwater Pneumatophores – Specially adapted roots – Grow upwards – Diffuse oxygen

Two Studies on Mangroves and Tsunamis Gulf of Mannar and South Andaman Island – Degree and extent of mangrove damage – Two study sites Gulf of Mannar, Mandapam Island group Andaman and Nicobar Archipelago, South Andaman Islands – Remote satellite images from before and after tsunami Thailand – January 15 th, 2002 and December 30 th, 2004 – Mangroves as a buffer

Gulf of Mannar- Mandapam Island Group

Mandapam Island Group Negligible impact on the mangroves from the tsunami wave Uninhabited- no human interference Partially protected by Sri Lanka Protected the islands from damage Mangroves and other species have regenerated Decreased shoreline

Andaman and Nicobar Archipelago

South Andaman Islands Inland coastal forest – no damage Heavy damage to mangroves along creeks Submergence of island – meters (Chatterjee et al.)

Classified Map showing the degree and extent of Damage Mangroves in South Andaman Island (Chatterjee et al.)

Submergence of Mangroves Buries pneumatophores Causes non-exposure of breathing roots for 6- 8 hours a day

Thailand Study Site

Thailand 927 km mangrove line Under a lot of pressure and is being destroyed – Shrimp farming, coastal development, and tin mining Dominated by species Rhizophora – Specialized roots to bind marine and terrestrial sediments – Protects against tropical storms and waves

Geographic relationship between damage from tsunami and mangrove coverage Vegetation in areas without mangroves was highly impacted – Low density mangrove areas faced high damage and land cover change of approximately 26.87% Mangroves resisted force of the tsunami – High density mangrove areas experienced approximately 2.77% change Recommends a mangrove buffer – m – Reduce damage from a potential tsunami wave

Background – Indian Ocean Tsunami Magnitude Up to 30m (98 ft) waves, up to 2km inland Circa 230,000 killed, millions displaced More than $14 Billion in humanitarian aid alone

Areas most Affected Tsunamis typically hit low lying areas, which are predominantly agricultural in much of the developing world The response of urban ecosystems is not well documented, and as these environments are heavily modified already, we can leave them out of the discussion Thus, agricultural remediation and environmental response in low lying lands is generally the most important aspect of speedy recovery

Immediate response: FAO Interventions FAO (Food and Agricultural Organization) broke down damage into three problem types: – Field Level Damage (such as sediment deposits, uprooted crops, salination, etc) – Infrastructure Damage (roads, irrigation, etc) – Farming Capacity Damage (loss of workers, farm animals, equipment, etc)

Damage typically increases as you approach the shore, particularly salt content in soil and water

Repair and Response Natural disasters are, by definition, something that a landscape sees as part of its natural evolution The timescale difference between natural landscape remediation and human requirements are the main issue Most resources and research have gone into restoring farmlands, and non-economically important areas are mostly left to sit and recover on their own Luckily, most affected areas see extensive rainfall, and thus have a natural means to flush salt out of aquifers and soils Human intervention can actually make the situation worse (such as in Sri Lanka)

Aceh Province Groundwater Contamination