Posted May 19, 2016 by admin in Natural Resource Management | 37 Total Views
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EFFECTS OF CLIMATE CHANGE ON OCEAN PH AND ITS INFLUENCES ON MARINE RESOURCES : STRATEGY TO SUPPORT NATIONAL FOOD SECURITY

HEAD OF RESEARCH TEAM : Dr. Mutiara Rachmat Putri
TEAM MEMBERS : Dr. Susanna and Dr. Agus Setiawan
OFFICIAL ADDRESS : Theoritic Oceanography Laboratory Research Group of Oceanography Labtek XI, 1st Floor, Institute Technology of Bandung Jalan Ganesha 10 Bandung 40132
EMAIL : mutiara.putri@gmail.com

As  one  of  the  regions  with  very  high  biodiversity,  coral  reefs  in  the  waters  of  Indonesia  have provided benefits to coastal communities through the availability of marine resources  such as fish, corals, mollusks, seaweed and other biological resources. Currently, changes in  sea  surface  temperature  caused  by  global  climate  change  is  known  to  have  caused  ocean  acidification  phenomenon  that  continues  to  expand  its  territory.  Meanwhile,  the  increased  concentration  of  carbon  dioxide  as  a  greenhouse  gas  has  also  led  to  degradation  of  coral  through  the  increase  of  dissolved  calcium  carbonate  which  resulted  in  a  decrease  in  the  rate  of  calcification  so  that  the  shell  of  the  reef  becomes  more  weak  and  easily  eroded.  Moreover, the influence of regional and global phenomena such as Indonesia Throughflow  (Arlindo)  and  El  Nino  Southern  Oscillation  (ENSO)  will  also  change  the  physical,  chemical,  and biological properties of marine environment that are important for the coral reefs and  other marine life such as primary productivity and pH of seawater.

This research try to analyse some changes in physical and chemical properties of seawater  and  their  potential  impacts  to  marine  environment  based  on  field  data,  a  numerical  model  (to  calculate  the  variation  of  ocean  pH  in  the  Indonesian  waters),  and  performing  some  experiment  in  the  laboratory  (to  see  the  effect  of  temperature,  salinity  and  pH  to  marine  biota).

From  the  numerical  model  we  found  that  in  the  Karimata  Strait  as  a  shallow  waters,  the  range  of  pH  is  between  7.6  and  7.8.  The  minimum  and  maximum  pH  are  found  in  October  and  March,  respectively.  On  the  other  hand,  pH  in  the  Banda  Sea  is  higher  compare  to  Karimata Strait. The value is between 7.8 and 7.9, maximum in September and minimum in  June (Putri et al., 2015a). Comparing the results of numerical model to field  measurement,  we  obtain  a  similar  months  for  the  maximum  and  minimum  pH  values,  but  in  the  western  part  of  Indonesia  waters,  such  as  the  Karimata  Strait,  the  pH  is  from  7.6  to  8,  while  in  eastern  parts  of  Indonesia  waters,  such  as  the  Banda  Sea,  the  pH  is  between  8  and  8.4.  Anthropogenic factors such as forest fires and additional input of dissolve inorganic carbon  (DIC)  and  total  alkalinity  (TA)  seem  to  decrease  pH  in  the  east  coast  of  Sumatra  by  approximately 0.2 from 2007 to 2012 (Avrionesti and Putri, 2015).

If  viewed  from  the  factors  of  climate  change,  sea  level  rise  in  the  eastern  region  of  Indonesia  is  largely  due  to  the  influence  of  the  El  Nino  Southern  Oscillation  (ENSO).  The  average sea level rise in eastern Indonesia over the last 20 years is about 6.2 cm/year (Titi  and Putri, 2015). This condition causes changes in temperature and increases the intensity  of  rainfall  that  decreased  the  salinity  and  can  trigger  an  ocean  acidification.  Some  experiments  in  the  laboratory  showed  that  season  changes  cause  high  variations  of  temperature,  salinity,  and  pH  in  the  Indonesian  waters.  Rise  of  temperature  by  2°C  and decrease  of  pH  by  0.4  unit  as  the  IPCC  scenario  can  cause  the  death  of  marine  life  such  as shellfish  and  coral  bleaching  in  some  parts  of  Indonesian  waters  (Putri, et  al.,  2015d).  Distribution of Net Primary Production (NPP) of Indonesia waters is strongly influenced by  the  ocean  dynamics  and  the  changes  of  seawater  temperature.  Using  the  Gaussian  Model  during  the  west  monsoon  and  first  monsoon  transition,  maximum  primary  productivity  in  the  Banda  Sea  is  found  in  the  layer  with  depth  of  30  to  40  meter  (100-250  mgC  m-2  day-1),  while  during  the  east  monsoon  and  second  monsoon  transition  the  maximum  primary  productivity (150-500 mgC m-2 day-1) is found in the surface layer (0 to 6 meter depth) due  to  the  upwelling  (Putri, et.al,  2015b).  Its  also  occurs  in  the  Bali  Straits.  The  upwelling  caused  the  abundant  of  chlorophyllWa  higher  during  the  east  monsoon  and  decrease  in  the  beginning  of  west  monsoon.  The  abundance  of  chlorophyllWa  during  the  east  monsoon  is  one  of  the  indicators  that  correlated  with  the  abundance  of  Lemuru  fish  where  the  maximum  catch  occurs  during  the  second  transition  monsoon, in  September-October-November (Putri, et.al, 2015c).

From  these  results  we  conclude  that  climate  change,  which  is  can  be  identified  from  sea  surface height anomaly (sea level anomalies) data as well as ENSO variation, will affect the  Indonesian  marine  condition  through  the  changes  of  physical,  chemical,  and  biological  properties  of  seawaters.  The  existence  of  anthropogenic  factors  from  various  human  activities also gives high contribution to these changes.

LIST OF RESEARCH OUTPUT

a Putri,  M.R.,  A.  Setiawan,  and  M.  Safitri,  2015a.  Variation  of  ocean  pH  in  the  Indonesian  Waters”, AIP Conference Proceedings 1677, 060021 (2015); doi 10.1063/1.4930701.

b. Putri,  M.R.,  A.  Setiawan,  and P.  Kemili,  2015b.  Net  Primary  Production  Variability  of  the  Banda Sea. Draft paper for American Journal of Environmental Science.

c.   Sari,  T.  and  M.R.  Putri,  2015.  Identification  of  Sea  Level  Variation  from  Multivariate  ENSO  Index  around  Small  Islands  in  Eastern  Indonesia,  poster  presentation  on  International  Conference  Small  Islands  Research  in  Tropical  Region  –  The  Spermonde  (SITRE), Makassar, 15W16 September 2015.

d. Putri,  M.R.,  A.  Setiawan,  and  T.L.P.  Yulianingrum,  2015c.  Vertically  ChlorophyllWa  Variation and the Lemuru Fish Abundant of Bali Stratis. Draft paper for National Journal  (Jurnal Ilmu dan Teknologi Kelautan).

e.  Avrionesti  dan  M.R.  Putri,  2015.  Perhitungan  Konsentrasi  Karbon  Antropogenik  di  Pesisir  Timur  Sumatra  Hasil  Pengamatan  Oktober  2012.  Prosidings  Seminar  Hasil  Penelitian Nasional, Universitas Brawijaya, Malang.

f. Putri, M.R., A.W. Radjab, and W.M. Tatipatta, 2015d. Laboratory Results : Effect of Ocean  pH on Grafarium Tumidum Shell in Ambon Bay. Draft paper for National Journal (Jurnal  Airaha)

g.   Ocean  pH  Mapping  of  Indonesia  waters  as  a  benchmark  for  the  Marine  and  Coastal Environment Management  (www.oceanography.itb.ac.id)


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