Looking back on the expedition it’s been tough work of long days in the field and long nights processing samples, but it has been immensely satisfying. We will return home with a computer full of data!

We’re very grateful to the great team at the TNC research station and at Papua Diving. They supported us in many ways and it was so nice to see how everybody got completely involved in the project – it clearly was not only an adventure for us, everybody got a kick out of discovering new lakes in islands that none of us had been to before!

If you’re coming to this blog for the first time and want to read the entries in chronological order, you’ll have to start at the bottom.

TNC Misool Station

overview of lakes

The expedition has been a great success, we located over 40 marine lakes new to science!

Some lakes turned out to be impossible for us to reach due to treacherous cliffs surrounding the lakes. If we had real rock-climbing equipment we would possibly have been able to do it, but even then there’s little way of climbing razorsharp yet brittle karst cliffs that go straight up at a 90 degree angle…..

The diversity of lakes that we did get to survey is immense. Different colors, different depths, salinities, shaped, sizes, and lots of different organisms. On the whole sponges, algae and mussels were the most dominant groups.

Video from inside a lake of cliff and jungle surroundings

Marine lakes represent a geomorphological gradient of highly connected lakes to highly isolated lakes. The highly connected lakes contain water that is similar to the reefs and house mostly species from reefflats, sometimes even stony coral.

Video of coral in a more connected marine lake

The more isolated the lake is, the lower the salinity typically is and the more unique species it contains. In the isolated lakes of Misool we have found many rare species that are only known from a few isolated lakes in the world. Additionally we have collected at least 10 species new to science.

Video of sampling among mangroves in a highly isolated marine lake

surveys

Video climbing through jungle to marine lake

not so undiscovered

The isolated water bodies of marine lakes are, like island systems, extremely vulnerable to threats from human activities. Particularly the highly isolated lakes could be irreversibly damaged. Some of the lakes near villages or the ‘resorts’ (camp accommodations north of Panah Panah for pearl farm workers) contained floating devices with cages. These were used to temporarily store recently caught fish. The introduction of fish or any other non-native marine species can radically change the diversity within the lakes. Introduced species can become invasive and dominant which could ultimately cause endemic lake species to go extinct. This actually also applies to us, so we always rinse all our gear in the evenings to make certain we do not unintentially bring in propagules of alien species.

Within Misool the most extreme form of exploitation was in a lake on the island Karwop. The whole lake had been transformed into an aquaculture containing fish such as tilapia. The density of fish was so high that the turbid water was literally bubbling with fish. The limestone rocks surrounding all lakes in Misool are porous and allow exchange of water with the adjacent waters. This means that the water from the aquaculture containing high nutrient concentrations and possible bacteria is a likely seeping to the surroundings, possibly causing harm to the coral reefs. It is a rather destructive practice that is also used in lakes of Vietnam; we sincerely hope it does not become common practice in Misool.

lunch

On nice days we would select one of the many uninhabited islands with Bounty-advertisement-beauty as our lunch location. If we were lucky Romel had caught some fish while we were working in the lake. Grilled fish over a fire, add some rice and coconuts and life is good.

However this trip was characterized by rain, so soaked rice was more often than not the motto.

shivering in the tropics

Ok, so you think about the tropics and most of you will think HEAT. And this is true. In part atleast. Yes the air temperature ranges between 35-40C and the sea between 28-30C. Yet for many a marine biologist doing fieldwork in the tropics means a lot of shivering cold. We spend most of the day on boats, exposed to all the elements, so no shortage of getting soaked by (cooler) rain and then being blown about for hours while remaining damp. Allright that may not be much of a convincer to some. The major source of shivering comes from the ages we spend under the water. 30C is pretty warm for seawater, yet it is still a good 7C lower than body temperature. When you spend 2 hrs diving, barely moving while you are recording data, even with a 5mm wetsuit, you can come up shivering. Well we do at least. If it’s sunny the shivering can subside soon enough, however we’ve had mostly rainy days so that meant quite continuous shivering. Sometimes I think I’ve never felt so cold as in the tropics….