life and death at chek jawa 9th august 08

LIFE AND DEATH LIFE AND DEATH AT CHEK JAWAAT CHEK JAWA

99thth August 2008 August 2008

I volunteer with…I volunteer with…

► Team SeagrassTeam Seagrass► Naked Hermit CrabsNaked Hermit Crabs► Semakau intertidal walks with Semakau intertidal walks with

Raffles Museum of Biological Raffles Museum of Biological Research (RMBR)Research (RMBR)

Key pointsKey points of this session of this session1.1. High Biodiversity of Chek JawaHigh Biodiversity of Chek Jawa2.2. Mass death on January 2007Mass death on January 20073.3. How this study began?How this study began?4.4. What caused the mass death?What caused the mass death?5.5. How are the marine animals recovering?How are the marine animals recovering?6.6. What is the future of Chek Jawa?What is the future of Chek Jawa?7.7. Experiences of this projectExperiences of this project

Have you been to Have you been to Chek JawaChek Jawa before? before?

Where isWhere is Chek JawaChek Jawa

Chek Jawa

Chek Jawa is lauded for its high Chek Jawa is lauded for its high biodiversity biodiversity

Figure from

Ria Tan

Six distinct ecosystems

exist at Chek Jawa

and it is abundant

with locally rare fauna and flora

Coastal Hill ForestCoastal Hill Forest

MangrovesMangroves

Rocky ShoreRocky Shore

Photos: N. Sivasothi

Sandy EcosystemsSandy Ecosystems

Photos: Ria Tan

Seagrass LagoonSeagrass Lagoon

Coral Rubble AreaCoral Rubble Area

Photos: Ria Tan

URA development guide plan 1997URA development guide plan 1997

To be reclaimed

Chek Jawa reclamation deferred!Chek Jawa reclamation deferred!

Mass mortality Mass mortality occurredoccurred

on January 2007on January 2007

After a period of exceptional heavy rain After a period of exceptional heavy rain in Jan 2007, a field trip to Chek Jawa in Jan 2007, a field trip to Chek Jawa

revealed…revealed…

LivingLiving Carpet Anemones Carpet Anemones

DyingDying Carpet Anemones Carpet Anemones

LivingLiving Sponges Sponges

DyingDying Sponges Sponges

LivingLiving sea stars and sea cucumbers sea stars and sea cucumbers

DyingDying sea stars and sea cucumbers sea stars and sea cucumbers

Soft bodied marine animals affectedSoft bodied marine animals affected

Asking Asking questionsquestions►What happened at Chek Jawa?What happened at Chek Jawa?►What caused the mass death?What caused the mass death?►Why were some animals more Why were some animals more

affected as compared to others?affected as compared to others?►Is this mass death a tragic event?Is this mass death a tragic event?►Will Chek Jawa recover? Will Chek Jawa recover? ►If yes, how?If yes, how?

Answering Answering questionsquestions through.. through..

UROPSUROPS

What isWhat is

U R O P sU R O P s

Undergraduate Research Undergraduate Research Opportunities Programme in ScienceOpportunities Programme in Science

►doing an independent research project doing an independent research project ►work with Faculty staffwork with Faculty staff►work in a specific field of studywork in a specific field of study

What motivated me to do What motivated me to do this this Chek Jawa studyChek Jawa study??

►CuriosityCuriosity►Answer questionsAnswer questions►gain experiencegain experience►Relevance to conservationRelevance to conservation

My My supervisorssupervisors1. Mr. N. Sivasothi 1. Mr. N. Sivasothi (Department of Biological Science, NUS)(Department of Biological Science, NUS)

2. Dr. Peter Todd 2. Dr. Peter Todd (Department of Biological Science, NUS)(Department of Biological Science, NUS) 3. Dr. Dan Rittschof 3. Dr. Dan Rittschof (Duke University)(Duke University)

Photo: Ria Tan

At the beginning…At the beginning…

►reading up various literatures reading up various literatures ►compilation of data and past observationscompilation of data and past observations►Discussions with my supervisors and expertsDiscussions with my supervisors and experts►Conducting of field surveysConducting of field surveys

Figure: Aerial photograph of Chek Jawa (squared in white) and its surrounding. Photo by Google Earth.

Kuala Johore

Salinity decreases

Heavy rainfall and flooding eventsHeavy rainfall and flooding events

►Intensified northeast monsoon in Intensified northeast monsoon in December and JanuaryDecember and January

►Flooding reported in different parts of Flooding reported in different parts of Malaysia and SingaporeMalaysia and Singapore

►Freshwater surge into Chek Jawa from Freshwater surge into Chek Jawa from Johor RiverJohor River

Chek Jawa

Enhanced runoff?

Narrowed Narrowed Johor Straits Johor Straits channel channel amplifies amplifies dischargedischarge

How How widewide is the mouth of Johor River is the mouth of Johor River

What may have contributed to the What may have contributed to the mass death? mass death?

1.1. incidents of low tideincidents of low tide2.2. amplified river output amplified river output 3.3. prolonged direct rainfall prolonged direct rainfall

Side view

Bird’s eye view

Cumulative rainfall data for Cumulative rainfall data for January 2007January 2007 taken from Changi Meteorological Stationtaken from Changi Meteorological Station

0

50

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.

1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th 21st 22nd 23rd 24th 25th 26th 27th 28th 29th 30th 31st

January 2007

Cu

mu

lati

ve

rai

nfa

ll (

mm

)

Prolonged Prolonged direct rainfall for about three days

Mass death first sighted

Incidence of low tide: Incidence of low tide: 11-14 January 200711-14 January 2007

1.51.616:00

1.34.415:00

1.12.314:00

1.12.313:00

1.22.412:00

14th

1.31.113:00

1.34.612:0013th

1.54.722:00

1.61.921:00

1.81314:00

1.624.113:00

1.410.712:00

1.37.411:00

12th

1.61.40:00

1.410.923:00

1.33.322:00

1.32.121:00

1.414.111:00

1.37.810:00

11th

Tide level (m)Hourly Rainfall (mm)HourJan-07

Amplified river output?Amplified river output?

Rainfall data to predict river water Rainfall data to predict river water level patterns for January 2007level patterns for January 2007

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1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th 21st

December 2006

Cu

mu

lati

ve r

ain

fall

(m

m)

0

50

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.

1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th 21st 22nd 23rd 24th 25th 26th 27th 28th 29th 30th 31st

January 2007

Cu

mu

lativ

e ra

infa

ll (m

m)

December 2006 January 2007

-1.5

-0.5

0.5

1.5

2.5

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4.5

5.5

6.5

.

1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th 21st

December 2006

Riv

er

wat

er le

vel (

m)

River water-level data for December 2006, River water-level data for December 2006, taken from Johor River, Kota Tinggi.taken from Johor River, Kota Tinggi.

Conducting of field surveysConducting of field surveys

2.2. Transects surveys (once in 3 months)Transects surveys (once in 3 months)3.3. Monitoring of different groups of marine Monitoring of different groups of marine

animals (once in 2 months)animals (once in 2 months)

Sometimes we set off early…Sometimes we set off early…

…sometimes we go back late

T6T6

T5T5

T4T4

T3T3

T2T2

T1T1

N

Six transect linesSix transect linesT1

T2

T3

T4

T5

T6

T1

T5

T4

T3

T2

T6

Transect surveyingTransect surveying

Sometimes disasters do happen…Sometimes disasters do happen…

……af t e r a day’ s har d wor kaf t e r a day’ s har d wor k

0

5

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25

30

35

5-Jul-07

28-Sep-07

23-Dec-07

20-Feb-08

5-Jul-07

28-Sep-07

23-Dec-07

20-Feb-08

5-Jul-07

28-Sep-07

23-Dec-07

20-Feb-08

5-Jul-07

28-Sep-07

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20-Feb-08

5-Jul-07

28-Sep-07

23-Dec-07

20-Feb-08

5-Jul-07

28-Sep-07

23-Dec-07

20-Feb-08

1 2 3 4 5 6

Transect

Nu

mb

er

of

tub

ewo

rms

Number of tubeworms between four periodsNumber of tubeworms between four periods

suggests recovery

Monitoring RecoveryMonitoring Recovery

•Specific fauna targeted

•Once every two months

•Record density

•Study changes

Monitoring Mussel BedsMonitoring Mussel Beds

A closer lookA closer look

Asian date mussel Asian date mussel

An invasive species

A friend or a foe?A friend or a foe?> can dominate and exclude some species by aggregation in high density

> may restrict growth of seagrass

> provide additional habitat

Dec 2007 vs Jan 2008Dec 2007 vs Jan 2008

suggests a possibility of mussel beds slowly being replaced away as recovery progresses

Latest updateLatest update from last Mondayfrom last Monday

Missing in actionMissing in action

Slowly but surely being eaten up?Slowly but surely being eaten up?

Real reason behind such an elimination is difficult to account for

More will be needed to give a scientific explanation

Carpet AnemonesCarpet Anemones

Photos: Ria Tan

•30 located and marked

•Shortest and longest diameter axis measured

•Tentacles counted

Not all things work!Not all things work!

Sea anemone morphology is variable Sea anemone morphology is variable

NOTNOT easy to study easy to study

What I’ve learnt from field What I’ve learnt from field applications from Dr Daphne Fautin?applications from Dr Daphne Fautin?

► anemones from tide pools anemones from tide pools contract when exposed to contract when exposed to airair

► can detach and movecan detach and move► difficult to determine sizedifficult to determine size► density differs density differs ► incorrect to correlated size incorrect to correlated size

with agewith age

Sand dollars Sand dollars

Sand stars Sand stars

Common sea stars Common sea stars

Button shells Button shells

Peacock Anemones Peacock Anemones

The sandbar before mass mortality is covered with several carpet anemones. After the mass mortality, the The sandbar before mass mortality is covered with several carpet anemones. After the mass mortality, the sand bar is almost barren of carpet anemones. These post mortality photographs were taken as part of sand bar is almost barren of carpet anemones. These post mortality photographs were taken as part of using photographs for comparison and also to monitor recruitment over time.using photographs for comparison and also to monitor recruitment over time.

12 January 2002

25 December 2007

16 August 2007

22 January 2008

Latest updateLatest update from last Mondayfrom last Monday

4 August 20084 August 2008

Still no anemones back on sand bar?

•long time to rebuild a population?

•Among the largest anemones

•live several centuries

•Replace themselves during their lifetime

•Reproduction is slow

LifeLife at Chek Jawa at Chek Jawa

What is the What is the futurefuture for for Chek JawaChek Jawa??

►Appears to be recoveringAppears to be recovering►Recruitment of larvae from nearby seeding Recruitment of larvae from nearby seeding

sitessites►Designation as protected area enhances Designation as protected area enhances

natural recoverynatural recovery►Marine life is vulnerable Marine life is vulnerable ►better understanding is essential to protect better understanding is essential to protect

Chek JawaChek Jawa

Some interesting Some interesting experiencesexperiences

Celebrating Celebrating ChristmasChristmas at at Chek JawaChek Jawa

http://bp2.blogger.com/_9jTkGowIILg/R-sh2V0wuXI/AAAAAAAADac/fp_sqkuX_CM/s1600-h/ria.jpg

On a more On a more seriousserious note… note…

Nearing Nearing submissionsubmission of report… of report…

Intense email discussions with Intense email discussions with various supervisors/experts etcvarious supervisors/experts etc

Corrections on my report draftsCorrections on my report drafts

How this project has enhanced my How this project has enhanced my undergraduate experienceundergraduate experience??

►Understand the meaning of Understand the meaning of researchresearch►Start questioning, analysing and exploringStart questioning, analysing and exploring►More questions than answersMore questions than answers►Walk out of comfort zone Walk out of comfort zone ►Some of best learning is Some of best learning is

by making mistakesby making mistakes

Friend who is inspired to do work at Friend who is inspired to do work at Chek Jawa too Chek Jawa too

What are my What are my future plansfuture plans ? ?

►Preparing to publish my findingsPreparing to publish my findings►Working on sea stars behaviour and ecologyWorking on sea stars behaviour and ecology► teaching after I graduate from NUSteaching after I graduate from NUS►Sharing experiences with my students Sharing experiences with my students

Find out Find out moremore about the project here about the project here

cjproject.blogspot.comcjproject.blogspot.com

http://cjproject.blogspot.com/

Thank youThank you!!

life and death at chek jawa 9th august 08

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