[Coral-List] Kakaban Island - anchialine lake wiith a low pH environmental setting

[tomascik at novuscom.net]

Dear colleagues,

For those working on ocean acidification and looking for new exciting 
natural field laboratories where to study how calcifying flora and fauna 
may cope in low pH environments under high temperature conditions, 
please have a look at the one pager in the following link:
  
https://www.researchgate.net/publication/365515214_Presence_of_Alveopora_tizardi_Scleractinia_Acroporidae_as_an_epibiont_on_molluscan_shells_in_an_anchialine_lake_of_a_raised_atoll_Kakaban_Island_East_Kalimantan_Indonesia_An_opportunist_or_a_survivor

Considering the wide interest in ocean acidification, as a result of 
climate change, the low pH anchialine marine lake on Kakaban Island 
offers a unique natural laboratory that has been greatly underutilized 
by both the Indonesian and international coral reef scientific community 
thus far. We decided to publish the short “Photogallery” note in Galaxea 
with the hope that it will generate new interest in this unique 
anchialine marine lake before the environmental conditions are changed 
by tourism and introduced species.

Kakaban Island is located on a depositional basin stretching from the 
Mangkalihat peninsula (East Kalimantan) to the Simporna peninsula 
(Sabah, Malaysia) along the northeast coast of Borneo. The atoll is 
located on a relatively flat submarine platform that is 200 to 300 m 
deep. It is located 60 km east of the Berau River delta, in a 
delta-front setting. While the origin of Kakaban remains unresolved, it 
has been suggested that the island represents a lagoonal reef of a 
former barrier reef complex that was located on the edge of the shelf 
off the coast of East Kalimantan. As the shelf slowly subsided it 
carried the barrier reefs further offshore, and as a result of the 
subsidence the atoll was formed in a Darwinian manner. Based on 
sedimentation rate estimates from the Moluccas, and the seafloor 
bathymetry around Kakaban, it has been suggested that the formation of 
the atoll took about 1-2 million years. At some point in recent geologic 
history the slowly sinking platform under Kakaban must have curved 
upwards and consequently raising the atoll 60 m above present-day sea 
level. During the uplift, the former atoll lagoon lost all surface 
connections with the sea, thus making it anchialine. The lake (i.e., old 
lagoon) is now connected to the sea only through a network of 
underground fissures, caves and solution channels. The 11 m deep lagoon 
(about 1.5 km wide and 2.6 km long) is surrounded by a densely vegetated 
coral ridge rising to a height of 45-60 m above present-day sea level. 
Kakaban Island is roughly 2.5 km wide and 6 km long.

I hope that some of you will find this unique setting exactly what you 
have been looking for and will try to establish rewarding research 
partnerships with universities and researchers in Indonesia (e.g., 
Universitas Diponegoro - UNDIP).

For those of you who are interested to learn more about Kakaban please 
have a look at:

https://www.researchgate.net/publication/236849592_Recently_discovered_landlocked_basins_in_Indonesia_reveal_high_habitat_diversity_in_anchialine_systems

and

https://www.researchgate.net/publication/259286986_The_ecology_of_'Halimeda_Lagoon'_an_anchialine_lagoon_of_a_raised_atoll_Kakaban_Island_East_Kalimantan_Indonesia

Cheers,
Tom