Growth of Mangrove in Volcano Mud

Since 29 May 2006, a mud volcano in Sidoarjo district of East Java, Indonesia, has been emitting hot mud at an average rate of more than 40,000 m3/day. The volcano is so called Lusi, which means “lu” for lumpur (mud) and “si” for Sidoarjo. From the geological standpoint, the mud is estimated to continue spewing for years. Mud volcanoes are geological phenomena due to overpressurized subsurface mud layers. Although it links to the gas exploration activities by Lapindo Brantas, the cause of the eruption has not yet been established. The nature of mud is still questioned since the reports show that the mud is not homogenous (UNEP/OCHA, 2006).

 

A more pressing concern after the eruption is how the mud should be discharged. Disposal scenario of dumping into the sea through Porong River is unpopular. It could lead to the water flow blockage and affect the coastal productivity. Some ecological engineers recommend the establishment of artificial mud island as the area of the waste material disposal. An artificial wetland system is proposed to receive and make use of deep earth eruptions and incorporate them into productive system (Awad, 2006, McLachan-Karr, 2006).  

Mangroves are the natural habitats of the Porong River Area. They have evolved in filtering waste and stabilizing sediments that run from the Porong areas. Because of their unique characteristics, mangroves are already organized to receive the mud within the artificial wetland system. Mangroves are expected to deal with rapid and large changes in environmental inputs. In related to this assumption, a preliminary assessment has been done in 2006-2007 to prove whether mangrove could survive within this mud. This study aims to investigate the probability of dominant mangrove species in Porong, which is Avicennia, to survive in “Lusi”.

 

Result

Within 10 days, Avicennia sp has shown fine growth compare to Rhizophora sp. There are no significant difference between the growth of mangrove with the media of simply mud and mudwith fertilizer. Direct and indirect sunlight is also one of the treatments that applied in thesamples. The current result does not show the significant influence of their growth with thosedifferent solar radiations setting. However, further observation is needed to conclude the findings.  

 

 source : Marine Conservation Team – IMRO

 

 

     

 

Wave on the mangrove

 Since the tsunami striken in 2004, mangrove became an interesting subject. Some say mangrove is the hero and show many pictures that compare the existing condition of the construction behind the mangrove. Indeed, not only mangrove but most all coastal vegetations were regarded as the buffer of this severe wave.

Yes, mangrove can absorb the wave, but I don’t think that mangrove is the hero. Mangrove is relatively a victim. It stabilizes the dynamical system on the coastline where the ocean and the land meet. Its function was forgotten, as consequence, people convert the mangrove forest into human settlement. This is the most mistake that people have made.

Now, people start to replant the mangrove in order to increase protection against the tsunami. But how long the mangrove can effectivelly absorb the tsunami wave ? Well, it is not an instant way. We can’t justify that by planting the mangrove today, we all will save tomorrow. In calm condition such as estuary, 3 year-old mangrove has height of only 2-3 meters. On the beach with very dynamic condition, we are very fortunate if all the replanted mangrove are alive and can grow well.

It is a simple way how we can survive from natural disaster such as cyclone, tsunami or storm wave. Just leave the existing condition of the mangrove forest (don’t convert into any kind of use) and increase our awareness of the ocean dynamic.