Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro-climate over the past 150 years

Charlotte L. Briddon; Suzanne McGowan; Sarah E. Metcalfe; Virginia Panizzo; Jack Lacey; Stefan Engels; Melanie Leng; Keely Mills; Muhammad Shafiq; Mushrifah Idris

doi:10.1002/geo2.90

Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro-climate over the past 150 years

Charlotte L. Briddon (Corresponding author), Suzanne McGowan, Sarah E. Metcalfe, Virginia Panizzo, Jack Lacey, Stefan Engels, Melanie Leng, Keely Mills, Muhammad Shafiq, Mushrifah Idris

Research output: Contribution to journal/periodical › Article › Scientific › peer-review

6 Citations (Scopus)

Abstract

Rapid development and climate change in southeast Asia is placing unprecedented pressures on freshwater ecosystems, but long term records of the ecological consequences are rare. Here we examine one basin of Tasik Chini (Malaysia), a UNESCO-designated flood pulse wetland, where human disturbances (dam installation, iron ore mining, oil palm and rubber cultivation) have escalated since the 1980s. Diatom analysis and organic matter geochemistry (δ13Corg and C/N ratios) were applied to a sediment sequence to infer ecological changes in the basin since c. 1900 CE. As the Tasik Chini wetland is a rare ecosystem with an unknown diatom ecology, contemporary diatom habitats (plant surfaces, mud surfaces, rocks, plankton) were sampled from across the lake to help interpret the sedimentary record. Habitat specificity of diatoms was not strongly defined and, although planktonic and benthic groupings were distinctive, there was no difference in assemblages among the benthic habitat surfaces. An increase in the proportion of benthic diatom taxa suggests that a substantial decrease in water level occurred between c. 1938 and 1995 CE, initiated by a decline in rainfall (supported by regional meteorological data), which increased the hydrological isolation of the sub-basin. Changes in the diatom assemblages were most marked after 1995 CE when the Chini dam was installed. After this time both δ13Corg and C/N decreased, suggesting an increase in autochthonous production relative to allochthonous river flood pulse inputs. Oil palm plantations and mining continued to expand after c. 1995 CE and we speculate that inputs of pollutants from these activities may have contributed to the marked ecological change. Together, our work shows that this sub-basin of Tasik Chini has been particularly sensitive to, and impacted by, a combination of human and climatically induced changes due to its hydrologically isolated position.

Original language	English
Pages (from-to)	e00090
Journal	Geo: Geography and Environment
Volume	7
Issue number	1
DOIs	https://doi.org/10.1002/geo2.90
Publication status	Published - 2020
Externally published	Yes

Keywords

diatoms
ecology
human disturbance
hydrological variability
palaeolimnology
Southeast Asia

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10.1002/geo2.90Licence: CC BY

Cite this

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title = "Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro-climate over the past 150 years",

abstract = "Rapid development and climate change in southeast Asia is placing unprecedented pressures on freshwater ecosystems, but long term records of the ecological consequences are rare. Here we examine one basin of Tasik Chini (Malaysia), a UNESCO-designated flood pulse wetland, where human disturbances (dam installation, iron ore mining, oil palm and rubber cultivation) have escalated since the 1980s. Diatom analysis and organic matter geochemistry (δ13Corg and C/N ratios) were applied to a sediment sequence to infer ecological changes in the basin since c. 1900 CE. As the Tasik Chini wetland is a rare ecosystem with an unknown diatom ecology, contemporary diatom habitats (plant surfaces, mud surfaces, rocks, plankton) were sampled from across the lake to help interpret the sedimentary record. Habitat specificity of diatoms was not strongly defined and, although planktonic and benthic groupings were distinctive, there was no difference in assemblages among the benthic habitat surfaces. An increase in the proportion of benthic diatom taxa suggests that a substantial decrease in water level occurred between c. 1938 and 1995 CE, initiated by a decline in rainfall (supported by regional meteorological data), which increased the hydrological isolation of the sub-basin. Changes in the diatom assemblages were most marked after 1995 CE when the Chini dam was installed. After this time both δ13Corg and C/N decreased, suggesting an increase in autochthonous production relative to allochthonous river flood pulse inputs. Oil palm plantations and mining continued to expand after c. 1995 CE and we speculate that inputs of pollutants from these activities may have contributed to the marked ecological change. Together, our work shows that this sub-basin of Tasik Chini has been particularly sensitive to, and impacted by, a combination of human and climatically induced changes due to its hydrologically isolated position.",

keywords = "diatoms, ecology, human disturbance, hydrological variability, palaeolimnology, Southeast Asia",

author = "Briddon, {Charlotte L.} and Suzanne McGowan and Metcalfe, {Sarah E.} and Virginia Panizzo and Jack Lacey and Stefan Engels and Melanie Leng and Keely Mills and Muhammad Shafiq and Mushrifah Idris",

year = "2020",

doi = "10.1002/geo2.90",

language = "English",

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Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro-climate over the past 150 years. / Briddon, Charlotte L. (Corresponding author); McGowan, Suzanne; Metcalfe, Sarah E. et al.
In: Geo: Geography and Environment, Vol. 7, No. 1, 2020, p. e00090.

Research output: Contribution to journal/periodical › Article › Scientific › peer-review

TY - JOUR

T1 - Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro-climate over the past 150 years

AU - Briddon, Charlotte L.

AU - McGowan, Suzanne

AU - Metcalfe, Sarah E.

AU - Panizzo, Virginia

AU - Lacey, Jack

AU - Engels, Stefan

AU - Leng, Melanie

AU - Mills, Keely

AU - Shafiq, Muhammad

AU - Idris, Mushrifah

PY - 2020

Y1 - 2020

N2 - Rapid development and climate change in southeast Asia is placing unprecedented pressures on freshwater ecosystems, but long term records of the ecological consequences are rare. Here we examine one basin of Tasik Chini (Malaysia), a UNESCO-designated flood pulse wetland, where human disturbances (dam installation, iron ore mining, oil palm and rubber cultivation) have escalated since the 1980s. Diatom analysis and organic matter geochemistry (δ13Corg and C/N ratios) were applied to a sediment sequence to infer ecological changes in the basin since c. 1900 CE. As the Tasik Chini wetland is a rare ecosystem with an unknown diatom ecology, contemporary diatom habitats (plant surfaces, mud surfaces, rocks, plankton) were sampled from across the lake to help interpret the sedimentary record. Habitat specificity of diatoms was not strongly defined and, although planktonic and benthic groupings were distinctive, there was no difference in assemblages among the benthic habitat surfaces. An increase in the proportion of benthic diatom taxa suggests that a substantial decrease in water level occurred between c. 1938 and 1995 CE, initiated by a decline in rainfall (supported by regional meteorological data), which increased the hydrological isolation of the sub-basin. Changes in the diatom assemblages were most marked after 1995 CE when the Chini dam was installed. After this time both δ13Corg and C/N decreased, suggesting an increase in autochthonous production relative to allochthonous river flood pulse inputs. Oil palm plantations and mining continued to expand after c. 1995 CE and we speculate that inputs of pollutants from these activities may have contributed to the marked ecological change. Together, our work shows that this sub-basin of Tasik Chini has been particularly sensitive to, and impacted by, a combination of human and climatically induced changes due to its hydrologically isolated position.

AB - Rapid development and climate change in southeast Asia is placing unprecedented pressures on freshwater ecosystems, but long term records of the ecological consequences are rare. Here we examine one basin of Tasik Chini (Malaysia), a UNESCO-designated flood pulse wetland, where human disturbances (dam installation, iron ore mining, oil palm and rubber cultivation) have escalated since the 1980s. Diatom analysis and organic matter geochemistry (δ13Corg and C/N ratios) were applied to a sediment sequence to infer ecological changes in the basin since c. 1900 CE. As the Tasik Chini wetland is a rare ecosystem with an unknown diatom ecology, contemporary diatom habitats (plant surfaces, mud surfaces, rocks, plankton) were sampled from across the lake to help interpret the sedimentary record. Habitat specificity of diatoms was not strongly defined and, although planktonic and benthic groupings were distinctive, there was no difference in assemblages among the benthic habitat surfaces. An increase in the proportion of benthic diatom taxa suggests that a substantial decrease in water level occurred between c. 1938 and 1995 CE, initiated by a decline in rainfall (supported by regional meteorological data), which increased the hydrological isolation of the sub-basin. Changes in the diatom assemblages were most marked after 1995 CE when the Chini dam was installed. After this time both δ13Corg and C/N decreased, suggesting an increase in autochthonous production relative to allochthonous river flood pulse inputs. Oil palm plantations and mining continued to expand after c. 1995 CE and we speculate that inputs of pollutants from these activities may have contributed to the marked ecological change. Together, our work shows that this sub-basin of Tasik Chini has been particularly sensitive to, and impacted by, a combination of human and climatically induced changes due to its hydrologically isolated position.

KW - diatoms

KW - ecology

KW - human disturbance

KW - hydrological variability

KW - palaeolimnology

KW - Southeast Asia

U2 - 10.1002/geo2.90

DO - 10.1002/geo2.90

M3 - Article

SN - 2054-4049

VL - 7

SP - e00090

JO - Geo: Geography and Environment

JF - Geo: Geography and Environment

IS - 1

ER -

Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro-climate over the past 150 years

Abstract

Keywords

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