Marine Ecology Research

Blog

  • NAEM Posterprize 2009

    NAEM Posterprize 2009

    10 February Judith Sarneel and me found our way back (was it a Levy walk?) to Conference centre “De Werelt” for 2 days of total saturation by Ecological research during the Netherlands Annual Ecology Meeting in Lunteren: At daytime listen to “Allee effects”, early warning signals by spatial patterns, plantquality-herbivore interactions and at nighttime getting inspired from foodweb interations compared between seagrass, Serengeti-Mara, Hluhluwe (S.A.), and Barro Colorado (Panama) ecosystems.

    The second day it was time for Madelon and me to present our poster “Overgrazing by Green Turtles?” (PDF) together with 45 others. The poster were evaluated on scientific quality, clarity and attractiveness. Not without succes, like you will see below we won the NERN and NECOV 2009 posterprize, and 300 euros! We are very happy with this result, now its time to write an article from it to apply for the PhD paper award next year ☺

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    The only critics on the poster: increase fontsize of the author names

  • Is it seagrass? oh it has eyes

    If I’m with my nose between the seagrass I sometimes encounter camouflaged creatures which I would have missed if I wasn’t studying the seagrass. These encounters are most rewarding and will “make my day” If you have more examples of fauna mimicking seagrass, please send me your pics/movies. Click here to see some more seagrass associated fauna

    The Robust ghostpipefish comes in several colours but the seagrass-green one is my favourite of course :).

    Some more fauna in the seagrass bed, it hides between leaves, roots, in the sediment. Do you also want to see this? than join the project as an intern.

  • New Year : New URL

    Like you must have noticed, I’ve moved the Blog of my Phd project to Penyu.nl! “Penyu” is off course ‘Sea Turtle’ in Bahasa Indonesia and I’m more flexible to do things with the weblog. Please change it in your Favourites or RSS subscriptions.

    So what happened after my last blogs where I showed you pictures of my fieldwork in Kalimantan? For 3 months I was hiding behind high piles of samples in the laboratory of my University back in the Nijmegen, together with Laura. We analyzed soil and surface water for Ammonium, Phospate, Potassium, Sodium, Cloride, in the autoanalyser. And also we analysed Nitrate, which required a specific set-up with a Cadmium column as a reductor, which we first had to build ourselves. Furthermore we analysed Carbon:Nitrate ratios including stabile isotope ratio’s of dryed seagrass plants, to do this we had to shred the seperate plant parts into fine powder and fold 1500 samples into thin cups to balls of 1-1mm. We weighed biomass of all samples and made extracted elements from the dryed seagrass material by threating them with acid in the microwaveoven. Later we analyzed in the ICP spectometer what elements (including phosphate) were present in this extraction to check what the plants (-parts) took up from the water and soil. So combining this analysis we can now also compare C:N:P ratio’s. Many thank to Jelle Eygensteyn (Technician on the G.I.) for all the help with the analysis! Besides this, Madelon and I are also trying to calculate how many Green turtles the seagrass field could feed. First results look very promissing!

    The last week of December I also followed a course in Basic Statistics (highly recommended) in Wageningen. So this year I can start with the analysis of all the data that I gathered in 2008 during my first fieldperiod. And now it is time to test the hypothesis, see if my experiments worked, and to make new plans for next fieldvisit coming August.

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  • Research projects available 2009-2010

    *Next fieldwork period from Augustus 2009*

    Are you looking for a research project for your MSc specialisation? AND:

    • Interested in Marine Ecology and Ecosystem wide processes?
    • Would like to participate in fieldwork in the Derawan Archipelago, East Kalimantan, Indonesia
    • Would like to gain experience in fieldwork in an experimental setting and in chemical laboratory technique
    • Highly motivated & enjoys working in field and lab?
    • Interested in being a co-author on a scientific paper?

    Then please send a 1-2 page CV and a letter with your motivation to me: m.christianen@science.ru.nl

    Background
    The objective of our project:

    • We wish to address the possible shifting states of seagrass in relation to eutrophication and turtle grazing, using field experiments in the Derawan Archipelago, Kalimantan, Indonesia.
    • In parallel, we wish to obtain insight in the variation in production and community composition of seagrass assemblages between sites at diffent distance to the river and relate this variation to spatial and environmental variables.

    Most field experiments will be carried out in the coastal zones of the Berau and Mahakam rivers, East-Kalimantan, Indonesia. Ecosystems states (e.g. eutrofication, turtle grazing) and possible shifts between them will be provoked in a series of experiments involving turtle exclosures, turtle grazing mimicking and nutrient enrichments, both in the field and in the lab. The research will be carried by Radboud University Nijmegen (The Netherlands) in close cooperation with the Indonesian Institute of Science (LIPI, Indonesia) and the Netherlands Institute of Ecology in Yerseke.

    What you will do:
    Participate in fieldwork and exclosure-experiments. Participate in lab-work, collecting toxicity and biogeochemical data. We can discuss the details of the internship to create an exciting project that encompasses both your research interests and the goals of our project.
    Your project could start in the middle of 2009, with fieldwork (3-6 months) starting from beginning of August 2009. Due to application deadlines of funding (and visa preparations) It is advised to start early < 6 month before the start of your project with the preparations.

    In Dutch:
    Studenten gezocht: Stage Mariene Ecologie Indonesie,
    Als je op zoek bent naar een buitenlandse stage voor je master in Mariene Ecologie / Biologie lees dan bovenstaande beschrijving even door. Ik ben op zoek naar studenten die bereid zijn om voor hun master project ook veldwerk uit te voeren in het buitenland. Indonesie op het eiland Kalimantan voor verschillende maanden. Heb je interesse, neem dan contact met me op.

  • Enhalus acoroides in Marine lake!

    In august I visited Maratua for some measurements on the seagrass there. When I arrived the water was too high to work; time for some exploring! So I asked a man from the village about the marine lakes there. Off we went, through palm forests and mangroves with a “parang” cutting out our way. And then we reached this marine lake. The jellyfish were a lot smaller then those of Kakaban lake and the other more famous lake of Maratua. And when I reached the opposite of the lake I found … Enhalus acoroides!! I still have to check the literature but it’s very interesting to find this species here! This marine lake has a lower salinity (26-28‰) than the surrounding ocean (33%-34%) because of the filtering effect of the coral and years of dilution by rainwater. I know seagrass can cope a large range of abiotic factors but finding this species here suprised me. Do you know more about this, and have you seen this somewhere else? I’m pleased to receive your comment! The lake was also very turbid at the shore as you can see on this pictures (click for more pics).

  • NH4 toxicity experiment

    After performing the same experiment with transported Thalassia hemprichii last year I wanted to test the same treatments in the field. So after some creative thinking I came up with this set-up (click for more pics):

    I’m (amongs others) testing if high ammonia concentrations could cause troubles to seagrass.

  • More Fieldwork at Derawan

    Time is flying. The enclosure experiment is finished and Laura and Madelon left for their holidays. Time for me to visit the civilized world and put some pictures on the internet. It isn’t very structured but that is because only emailing this pictures costed me 1 1/2 a small discription can be found next to the pictures. The last 3 weeks will be spend on performing an NH4 toxicity experiment and a comparison of seagrass productivity at an island close to the river compared to an island far from the river.

  • Berau and Monkeys

    Time for a presentatie for WWF, TNC and the local goverment in Berau about our research in Derawan. After a morning with presentations (Nina thanks for the translation in Bahasa Indonesia) and a very nice discussion it was time for a afternoon of jungle. We rented a boat and drove 0,5 hours from Berau to a small river where it was seeming with monkeys. The “Orang Belanda” Proboscis monkey was there and 4 other species. Not al pictures are sharp but more for the archives 🙂

  • Ongoing fieldwork

    Two months into my first research period I would like to update you on my progress. Because it’s almost impossible to post from my research location on Derawan I will show a compilation of photo’s. When I will be back in the Netherlands I will elaborate some more on the specific experiments. Click on the photo for all the research photo’s.

  • Turtles @ Derawan

    In the first week at Derawan I saw so many turtles, therefore a post about the “production of new turtles”. Yesterday night I saw 4 turtles (Chelonia mydas) crawling on the beach to search for a suitable site to lay their eggs above the high tide line.

    She digged out a large hole in the surface of the beach using a swimming movement of her front flippers, creating the “body pit”. After ten minutes or more, actively throwing sand behind her, she beginned digging with her hind limbs, excavating the egg chamber of about 60 cm deep. Without pausing she continued laying 90 ‘ping-pong-sized-eggs’ (While the eggs are being deposited into the egg chamber, they can tolerate bouncing, rolling, tumbling or handling, but about two hours after being laid, the embryo will resume development, and may be killed by a simple roll of the egg.) Ferry from the WWF digged up the eggs to protect them from poachers. Now we have to wait 45-70 days for the small Tukik (turtle hatchling in Bahasa Indonesia) to hatch. Higher temperatures produce more females and result in shorter incubation periods. At Derawan Ferry will check development of the nests so that he can digg the eggs out and release the small flippering friends before poachers or predators find them.
    After nesting, the female went back to the coral reef to rest and complete the next clutch of eggs. They are known to mainly rely on their stored fat reserved while resting and completing the next clutch of eggs. She can lay several clutches of eggs at approximately two-week intervals before finally migrating back to her feeding ground. We are still in doubt if the mother turtles are the same ones grazing on the seagrass fields in front of Derawan at daytime, or if they only visit this Island to lay their eggs and travel back to their feeding ground.