Indonesian mangroves prove to be ‘sponge gardens’

Gepubliceerd op
16 mei 2013

The mangroves in the Caribbean are famous for housing a unique and diverse sponge fauna. Indonesia contains the most diverse mangrove ecosystems in the world, covering an area of almost 50 000 km2 , yet an ardent belief existed among sponge biologists that Indo-Pacific mangroves do not support the same type of sponge diversity as those in the Caribbean. Lisa Becking of IMARES Wageningen UR, together with her colleagues from Naturalis, studied sponges in mangroves in Indonesia along the coast and in marine lakes.

Photo: Sponges (pink and brown) and sea squirts (yellow) on a mangrove root. Photo's by Lisa Becking

Colourful diversity

This research shows that the opposite is true: Indonesian mangroves in fact display a colourful diversity of sponges! Particularly marine lakes, small bodies of seawater surrounded by land, proved to be a ‘sponge gardens’ where the coast was covered by a colourful carpet of woven sponges. During this study many undescribed sponges species were found, these species are new for science.

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The aim of the study was to quantify spatial variation in the abundance and species composition of sponges in marine lakes and adjacent coastal mangrove systems in the Berau region of Indonesia. Variation in species assemblages between localities can provide information on marine area relationships or connectivity, reflecting the processes operating in those areas. Knowledge of species diversity and spatial distribution patterns are furthermore essential for the design of successful Marine Protected Areas.

Sponges were chosen as a target group to measure biodiversity, because sponges are one of the most diverse taxa in the lakes and important players in reef and mangrove systems outside of the lakes in terms of diversity, biomass and filtering activities. 

New sponge species

A total 10.167 individual sponges were counted. These belonged to 115 species of which at least 40 are new to science. The new species were all found in marine lakes. Marine lakes are vulnerable to anthropogenic threats such as exploitation and alien species introduction. The findings of this research therefore have important implications for conservation. As a result , there the researchers collaborated with WWF/The Nature Conservancy Berau.

Research in new systems in the Tropics will inevitably lead to the discovery of new species for science. And unique species could have unique compounds that may be beneficial for humans. Because sponges also can be seen as little pharmacies – they produce a plethora of toxins that can be interesting for the pharmaceutical industry. For example, Zovirax®, the cream that anyone who suffers from herpes will know well, contains the compound Acyclovir which is derived from a spongecompound.

Coral Triangle

The sea covers over 70% of the earth, approximately 1-10 miljon species live in the sea of which it is estimated that two-thirds is yet undescribed. The region of the present study is in the Coral Triangle, the area between Malaysian, Philipinnes, Indonesia. And Papua New Guinae with the highest marine biodiversity on earth. With the present study we have inventoried a large number of new species and we are in the process of scientifically providing names for them. As such this study aids in a small way in closing the vast gap in biodiversity knowledge.