Marjolijn Christianen

Together with Nicole Esteban we have a nice paper out on #oceanoptimism: Climate change impacts clearly threaten many species. Sea turtles are a flagship conservation group and one major threat of climate warming is the feminisation of populations which may occur since all species have temperature dependent sex determination with female hatchlings being produced at warmer [...]

Our new paper that just came out today in Marine Biology research suggests so: Press release by Bureau Waardenburg/WUR below: And – in Dutch – an interview by NPO radio 1, science program Focus, about questions that leave you awake at night, broadcasted between 2-6 am. Underwater discovery oyster bed reveals native oyster mysteries The flat [...]

Green sea turtle digging its own watery grave due to invasion of non-native seagrass press release written by Jac Niessen and Lonneke Dortmans (Wageningen University) about our new paper that came out today in Journal of Ecology  (pdf) “Megaherbivores may impact expansion of invasive seagrass in the Caribbean” A seagrass species from the Red Sea [...]

A new paper by lead author Alan Rees and collegues reviews how we can use drones and other UAVs in sea turtle research and conservation. Here we review the diverse ways in which incorporating inexpensive UAVs may reduce costs and field time while improving safety and data quality and quantity over existing methods for studies [...]

Today our new paper came out in Frontiers of Marine Science. Emerging from the 12th International Seagrass Biology Workshop, held in October 2016, has been the view that grazing marine megafauna may play a useful role in helping to identify previously unknown seagrass habitats. Here we describe this concept, showing how detailed information on the distribution [...]

Can we estimate the exposure to river plumes for coastal ecosystems? During my PhD fieldwork in East Kalimantan I had the opportunity to collaborate with a multidisciplinairy team of hydrologists, physical geologists, modelers, coral reef biologists to study this. In this paper led by Ayi Tarya (Bandung Institute of Technology), Ton Hoitink (WUR) we found [...]

Today was my first day at the Aquatic Ecology and Water Quality Management group at Wageningen University. This is the official start of my NWO-VENI grant “Global defaunation and plant invasion: cascading effects on seagrass ecosystem services”. Looking forward to work here and expand my research (network)! More on this new research soon!     [...]

A short update to announce that 3 new co-authored papers have been accepted this month! So do you want to know why use FastlocGPS? Check out our comparison of Green turtle home range with Argos in Caribbean, Indian Ocean & W Australia Did you know?: Seagrass ecosystem trajectory depends on the relative timescales of resistance, [...]

Happy news! I received a personal VENI (research) grant today, from the Netherlands Organization for Scientific Research (NWO)! To work for 3-4 yrs on “Global defaunation and plant invasion: cascading effects on seagrass ecosystem services”. It will involve field experiments and a regional survey in the Caribbean and development of a new tools for global [...]

What fuels the Wadden Sea food web? This is the question that we addressed  in one of the largest ecological research projects in the Netherlands, the recently finalized “Waddensleutels” program. The answer is surprising, and has been published last month in Ecology. “Benthic primary producers are the solar panels that fuel the Wadden Sea food web” [...]

Seagrasses are often the “ungly duckling” in marine conservation, and receive disproportionally little attention in the media and in scientific studies when compared to mangroves and coral reefs. However, seagrasses are essential components of coastal zones due to their extremely high productivity and the high biodiversity they support. So time for more research! Inside Lac [...]

Our new paper is online available from today in Biological Conservation: a pdf here! The highlights of this paper: Shellfish reefs strongly modify habitat conditions in soft-sediment ecosystems. These non-trophic interactions strongly alter community and food web structure. Simple food web metrics captured these changes; classic community (biodiversity) metrics did not. Food web metrics are a useful [...]

Hello Everyone, Marjolijn has introduced me in her earlier posts; I am Fionne Kiggen and at the moment I am undertaking sea turtle research in St Eustatius for my Masters thesis at Wageningen University. I currently have two experiments running, one on Zeelandia beach on the Windward side of the island, and the second on [...]

Our in-water survey of sea turtles and their habitats in St. Eustatius (a.k.a. “Statia”) was very successful. We aimed to collect data to analyse the habitat use and population connectivity of green and hawksbill turtles as part of a larger NWO research program encompassing the 6 Dutch Caribbean Islands. Together with STENAPA (National Park authority of St Eustatius) and volunteers, and support [...]

Based on the monitoring data on nesting turtles that Jessica Berkel and her team at STENAPA are collecting we were able to predict the turtle’s return to the beaches. For this we used the inter-nesting durations of the first green turtles tracks that were reported for Zeelandia beach, St. Eustatius. Equipped with a turtle box, satellite transmitters, our red [...]

During our fieldwork on St. Eustatius. Laurent helped as a volunteer to catch turtles. He also made some really nice video footage while free diving. His guest post: “Being a volunteer in a scientific mission is very simple : You just have to listen to the Project Leader, and you have to be available anytime, [...]

Sea turtle sex is not determined at the time of fertilization like in humans, it is set by the temperature level during nest incubation. Recently for some small island rookeries througout the Caribbean researchers reported a shift towards a more female dominated hatchlings/populations as nest temperatures slightly increased in these areas (warmer beaches result in female turtles). At St. [...]

Lisa Becking (Wageningen University and IMARES) and I, together with Sea Turtle Conservation Bonaire (STCB) ; Mabel Nava, Sue Willis and Robert van Dam have shown in a recent publication that sea turtles who breed in Bonaire, Caribbean Netherlands, migrate great distances of up to 3500km to reach their foraging grounds across the Caribbean in 10 different countries. [...]

Bon dia! My name is Moniek and as an Ecology and Evolution student at the University of Groningen I have been doing fieldwork on Bonaire for my MSc internship. Most importantly I have been continuing the turtle exclusion experiment in Lac Bay; going out with a kayak and diving gear to measure and/or clean at [...]

Grazing is an important driver of ecosystem functioning! Not only in seagrass ecosystems :). This paper is a result of a very nice collaboration with Liesbeth Bakker and other colleagues working on herbivory in other ecosystems. Paper highlights: In this paper we show that herbivores provide strong top-down regulation on freshwater macrophytes and seagrasses. Their effects are [...]