Just got back on the mainland. Last month we succesfully set-up a large experiment on Derawan to look at interactive effects of hydrodynamics & turtle grazing on seagrasses. This involved building 30 cages and 15 large underwater wave-bunkers for which we almost used al the sand from the nearby sand spit. To determine the location of the plots we used an unmanned aerial photo plane. A small disaster happened and the plane crashed in the telephone tower, and the plane is now in Switserland for repair. See below for a photo-report of the last month:
And were back! To give you an idea of what we did before travelling to our remote fieldwork site, here’s a (simplified) checklist:
Arrange research & travel permit, KITAS, letters for governors, certificate of good conduct police (10 trips, at least 3 days)
Give presentation at World Delta Summit & follow EcoDynamic Design workshop
Buy all research equipment (60 kg) from small shops all around Jakarta,
transport this on the back of Arifins’ motorcycle and busway to avoid being stuck for ours in Jakarta’s traffic jams
Book 25 domestic flight tickets
Get essential soto-ayam & es jeruk nipis,
Prepare 30 under-water cages at Wawans house
Introduce Iris & Peter to Indonesia
Visit the wedding of Arifin’s son that follows Indonesia’s principle: SMP (sesudah makan pulang; finished your food? go home)
Go to Open Science meeting (Jakarta) and give OSM workshop (Makassar)
This all with laryngitis under 33 degrees celsius in formal dress.
This time Iris and Peter will join me for their MSc. intership during this last fieldwork period of my Phd. Here they are presenting our new penyu-team merchandise. You can follow Peters’ stories here, and Iris’ on facebook
After a week of CERF-ing (Conference of the Coastal & Estuarine Research Federation) in Daytona Beach, Florida, USA, I was totally saturated with new knowledge. So a great time to go out to the field & spend a day searching for Florida seagrasses near Sebastian Inlet. Lori, our guide never saw the seagrass in such turbid & low biomass conditions and even when snorkeling in knee deep water we couldn’t see the seagrass or bottom. BUT I did saw my first manatee in the wild, they came very close to us (± 2m). A cool way to end a conference!
After a week of CERF-ing (Conference of the Coastal & Estuarine Research Federation) in Daytona Beach, Florida, USA, I was totally saturated with new knowledge. So a great time to go out to the field & spend a day searching for Florida seagrasses near Sebastian Inlet. Lori, our guide never saw the seagrass in such turbid & low biomass conditions and even when snorkeling in knee deep water we couldn’t see the seagrass or bottom. BUT I did saw my first manatee in the wild, they came very close to us (± 2m). A cool way to end a conference!
After some long days in the field we took in the camp kitchen. Fons and Tjisse worked all night to measure the photosynthetic efficiency of the seagrasses, which resulted in this cool picture:
Check the slide show for a report of our last week of research in Shark Bay. Tjisse, Fons and Leon left after 2 weeks and because we had already finished the research (and our research budget: Australia=super expensive!) Laura & me cool explore Ningaloo reef.
Here we saw a lot of Green turtles mating, and .. Humpback whales.. UNDERWATER
Now I am back in the Netherlands, and still have a month time to prepare for the 4 months of fieldwork in Indonesia.
Beautiful seagrass patterns of Sharkbay: Let the fieldwork begin!
The team: Laura, me, Leon, Fons & Tjisse above the seagrass patterns
The seagrass leaves of Amphibolis are still full of red pigment after the winter period and make a really beautiful underwater panorama..We were very lucky with the weather and could work in extremely calm waters. In September the water temperature is between 18 and 20 C and a 5mm wetsuit is still quit cold.
Tjisse and Fons are analyzing the photosynthetic efficiency of our seagrass samples until 5 in the morning
Before starting the real work we spend a week preparing the field expedition. This included a medical test, x-rays, discussing our plans with John and Di from UWA (University of Western Australia), arranging a camper, the necessary permits etc. Jennifer Verduin was so kind to host Laura and me in Perth. And we also had a nice evening with Paul and his family.
We surprised the hardware store assistant with a list of the strangest combination of fieldwork equipement, from osmocote to bamboo-sticks, to plaster etc. And bought 800 dollars of food to survive the next 4 weeks in Shark bay.
After arriving in Denham, Sharkbay (a 10 hr drive from Perth), it was time to take a first glimps of the seagrasses:
And the local fauna! Including loads of Dugongs, Sharks, Turtles, Emu’s walking inside mangroves, Kangaroos, and sea snakes later on.
At the look out at Eagle Bluff we saw sharks swimming around the seagrass patches.
Time for some fieldwork! This time not in Indonesia but 7 hours flying further east in Sharkbay, Australia!
Together with Laura Govers, Tjisse van der Heide, Leon Lamers and Fons Smolders and researchers for the University of Western-Australia we will investigate the driving mechanisms behind the unique seagrass patterns of Shark Bay (picture below). Recently, van der Heide et al. demonstrated that banded spatial patterns in seagrasses (France) resulted from a scale‐dependent feedback between seagrass and hydrodynamics. Moreover, additional measurements showed that stress predictably influenced patterning in the seagrasses, hence suggesting that self‐organized patterns might be a useful stress‐indicator in seagrass ecosystems. Now in Sharkbay, there are patterns at 2 scales: Inside larger seagrass bands smaller seagrass bands occur, we will try to unravel the underlying mechanisms of their formation. We will post updates of our fieldwork on this blog.
Last year I met Teresa Alcoverro and Rohan Arthur at the Turtle Symposium in India were we discovered that our research had a hudge overlap; we were both doing comparable work on ecosystems with very high densities of green turtles and declining seagrasses, and we only found this out just then. My lastest MS about habitat destruction by green turtles is in an advanced stage, so time to present my results at the lab in CEAB, in Blanes, Spain & discuss possibilities for comparing these special ecosystems of the Lakshadweep islands and the Derawan Archipelago where we both working in. Check out their great paper: “Implications of conserving an ecosystem modifier: Increasing green turtle (Chelonia mydas) densities substantially alters seagrass meadows“. Check also their interesting work showing that fishers of have been in conflict with turtles, and perceive that fish catches have declines over the years due to direct and indirect interactions with turtles. To be continued… (@ CERF)
The Radboud University has recently updated it’s “virtual classroom” with interesting microscopy pictures of tropical seagrasses and other submerged water plants, check it out, (Thanx Liesbeth Pierson)
Although this animal is already been found in 1996, this giant Archelon ischyros Turtle fossil of 70 million years old keeps impressing me.
Its “flipper-span” reaches 4.9 meters and its shell 4 meters across. Imagine snorkeling next to this this turtle. Did these ancient already graze on seagrasses? Probably not, it had a leathery carapace, and therefore this turtle seems more related to the present carnivorous leatherback turtle. The original fossile was found in Dakota by the South Dakota School of Mines and Technology . Thanks to Euroturtle for the link!
Update 1-6-2011: STUDENT RECRUITMENT CLOSED: both internship positions taken
I have 2 MSc. student internship opportunities available with fieldwork in Indonesia from end of November 2011 till February 2012. Students should already have finished 1 other internship. Contact me this month if you are interested.
During our divetrip to the Similan and Surin island in the Andaman sea I found some seagrass (a Halophyla sp. >8 cross veins) growing very deep, between burrows of the shy spotted garden eels. While I know that some species are found much deeper, e.g. 50m deep (Beer et al. 1982) I was quite happy finding it as a variation to the depressing coral reef. This reef consisted of 90% dead coral probably as a result of the 2004 Tsunami, 2010 Bleaching event (after some months with 34C water temperature, in contrast to the normal 29C), and some local dynamite fishing.
Here a group picture of al the people joining the ISBW inside the Emerald Cave after surviving the 80 meters of darkness to enter the cave in snake-formation:
Part of our Workshop was a fieldtrip were we spotted the dugong feeding trails (pic middle) of the 40 dugongs that live in the area around Trang. Further searches of Dominik Kneer and me after the workshop only resulted in a observation of 3 vage brown silhouettes underwater which we lost in the waves after a boat passed by.
On our first night we released our floating flowers at the Loy Kratong festival (every full moon in November, pic right)
I presented my first exclosure experiment (seagrass with nutrient addition and mimicked turtle grazing) at the conference and received a 2nd prize in the student presentation competition, yeah.
After our first meeting in Texel in 2009 our second meeting was in Samarinda, Indonesia. The university of Samarinda (UNMUL) hosted the meeting and in 2 days we were updated of the outcomes the 15 WOTRO/ KNAW Phd projects that are now running in the Mahakam and Berau river Delta, including my project. The projects within the East Kalimantan program are very diverse ranging from geological, GIS, physical geography, to ecology, social and law. Many local NGO’ and scientists joined the meeting making it an interactive meeting. And the end of the second day Irfan Cibaj (Total) took us to a very interesting outcrop were he showed us the history of the previous delta in 70 meters of delta deposits. We even learned that there were once hard corals in the Mahakam delta, and that this delta is one in a series of ±30 delta’s that are situated on top of eachother. That puts a the human lifespan into perspective. On the 3rd day a big boat was arranged to travel downstream to show us the apex of the Mahakam rivers and the fluvial and tidal channels that transport the water out and into the delta respectivily. Duddy demonstrated and collected some sediment samples. We closed with a delicious Indonesian diner at Mesra Hotel and I travelled to Derawan Island for 2 days of fieldwork (heavy rain see pic). It was my shortest trip to Indonesia ever. Thanx Retno Wulandari for the picture above!
Before attending the symposium there were 2 obstacles to take: Waiting before it was safe again to fly from north-europe after the gigantic ash clouds following the eruption of Eyajallajokull. And secondly, getting my businessvisa (3 days at the visa office) from the Indian Ambassy in The Hague. But the day before departure I finally received the visa and planes were flying again, so Goa, India, here I come!
After 2 days of pre-symposium workshops on stabile isotopes, south (-east) asia, and opportunities to include dugongs in turtle research, the main symposium began. After a very interesting talk of Teresa Alcoverro on Turtle Grazing, it was time for my first presentation for the 700 seaturtle people in the ecosystem functioning session (invitation only). Based on a lot of positive feedback afterwards the talk was very succesfull. Attending the symposium, its many interesting presentations and meeting so many seaturtle people from around the world motivated me a lot. Thank you all!
In January, National Geographic Indonesia published a very nice map about the important habitats for the green turtles in the Derawan Archipelago. See low resolution map below. The Editor in chief visited Derawan and interviewed all goverment NGO’s and researchers (me) having something to do with the green turtles in November and he made a good review about the most important turtle issues. Below the map you can find the text were I was quoted.
Unfortunately just after NG left, another big threat to the turtles in the area became clear. Over 100 turtles got stuck in a >1000m net in front of Maratua Island, clearly set out to catch turtles specifically. You can read more in the article of Frank Zindel. The last 4 years a turtle net (big mesh sized) was found on 4 occasions in this area and killed a hudge number of turtles: ±150 dead turtles in 2005, ±400 in 2007, ±100 november 2009, ±15 December 2009 and the Chinese illegal poaching can still continue until the local authorities have enough resources to patrol regularly in the area.
Translated (thanks google translate) from the text of NG Januari.…”Marjolijn christianen, a Dutch researcher who pursues seagrass in waters off the island, conveys her worries about many sea turtles that are run over by fast speedboats in the shallow water area were the banana boat attracks a lot of tourists. Turtle carapaces are scratched when they are hit by the engine propeller of the fast speed boat. This propellor also damaged seagrass beds. Another threat, which is huge but more subtle, is pollution from the mainland and from the island Derawan itself. “I study the interaction of nutrients from river pollution and household waste on seagrass beds and the feeding relationship with the green turtle” Marjolijn explaines. Pollutants bring nutrients that feed algae. The more algae that grow in shallow water prevent sunlight to reach the seagrass, so its growth is reduced. Seagrass is a staple food of sea turtles and may decline as a result of the pollution, seagrass and thus turtles are estimated to continue decreasing.”…..
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