The presence of M. galloprovincialis-type genes among the population of mussels in the Dutch Wadd... more The presence of M. galloprovincialis-type genes among the population of mussels in the Dutch Wadden Sea, historically described as M. edulis, was assessed. We applied the molecular technique in which a fragment of the gene coding for an adhesive protein of the byssus of mussels is amplified by PCR and assayed for length using electrophoresis. Among 321 individual mussels collected
This report will show that (1) the synoptic intertidal benthic surveys of the Wadden Sea (SIBES) ... more This report will show that (1) the synoptic intertidal benthic surveys of the Wadden Sea (SIBES) has the power to detect change; a requirement for the continuous monitoring of ecological effects of gas exploitation and that (2) with time, in combination with the other monitoring programmes, SIBES will have the power to determine the influence of actual land subsidence to benthos in the East Frisian area, where subsidence is currently minimal. The Dutch Wadden Sea is acknowledged for its ecological importance, but also for its natural resources like fisheries, gas and salt. In total it is estimated that more than 20 billion cubic metres of gas lie beneath the Dutch Wadden Sea. In the last decades, gas production has taken place under the Wadden Sea (Zuidwal and Ameland) and the province of Groningen (Slochteren). Since 2007, gas production also began in the East Frisian area. Modelling studies estimate that sediment infilling should compensate for land subsidence that occurs with gas...
The ability to change organ size reversibly can be advantageous to birds that perform long migrat... more The ability to change organ size reversibly can be advantageous to birds that perform long migrations. During winter, red knots (Calidris canutus) feed on shellfish and carry a muscular gizzard that weighs 10% of their body mass. Gizzard size decreases when these birds eat soft foods, e.g. while breeding in the tundra. We studied the reversibility and time course of such changes using ultrasonography. Two groups of shellfish-adapted knots (N=9 and N=10) were fed alternately a hard and a soft food type. Diet switches elicited rapid reversible changes. Switches from hard to soft food induced decreases to 60% of initial gizzard mass within 8.5 days, while switches to hard food induced increases in gizzard mass to 147% within 6.2 days. A third group of knots (N=11), adapted to soft food for more than 1 year, initially had very small gizzards (25% of the mass of shellfish-adapted gizzards), but showed a similar capacity to increase gizzard size when fed shellfish. This is the first non-i...
We studied phenology, staging time and refuelling in Broad-billed Sandpipers Limicola falcinellus... more We studied phenology, staging time and refuelling in Broad-billed Sandpipers Limicola falcinellus stopping over during spring migration in the Sivash (Black Sea, Ukraine) in May 1991–94. In the study area, peak staging numbers of 2000–2500 individuals occurred in the third week of May. In May 1993, 460 birds were marked with a yellow dye and 126 of these were colour-ringed. Before 28 May no departure of birds dyed yellow could be detected; by 3 June all birds had departed. Colour-ringed adults in mid May 1993 staged for a ...
The presence of M. galloprovincialis-type genes among the population of mussels in the Dutch Wadd... more The presence of M. galloprovincialis-type genes among the population of mussels in the Dutch Wadden Sea, historically described as M. edulis, was assessed. We applied the molecular technique in which a fragment of the gene coding for an adhesive protein of the byssus of mussels is amplified by PCR and assayed for length using electrophoresis. Among 321 individual mussels collected
This report will show that (1) the synoptic intertidal benthic surveys of the Wadden Sea (SIBES) ... more This report will show that (1) the synoptic intertidal benthic surveys of the Wadden Sea (SIBES) has the power to detect change; a requirement for the continuous monitoring of ecological effects of gas exploitation and that (2) with time, in combination with the other monitoring programmes, SIBES will have the power to determine the influence of actual land subsidence to benthos in the East Frisian area, where subsidence is currently minimal. The Dutch Wadden Sea is acknowledged for its ecological importance, but also for its natural resources like fisheries, gas and salt. In total it is estimated that more than 20 billion cubic metres of gas lie beneath the Dutch Wadden Sea. In the last decades, gas production has taken place under the Wadden Sea (Zuidwal and Ameland) and the province of Groningen (Slochteren). Since 2007, gas production also began in the East Frisian area. Modelling studies estimate that sediment infilling should compensate for land subsidence that occurs with gas...
The ability to change organ size reversibly can be advantageous to birds that perform long migrat... more The ability to change organ size reversibly can be advantageous to birds that perform long migrations. During winter, red knots (Calidris canutus) feed on shellfish and carry a muscular gizzard that weighs 10% of their body mass. Gizzard size decreases when these birds eat soft foods, e.g. while breeding in the tundra. We studied the reversibility and time course of such changes using ultrasonography. Two groups of shellfish-adapted knots (N=9 and N=10) were fed alternately a hard and a soft food type. Diet switches elicited rapid reversible changes. Switches from hard to soft food induced decreases to 60% of initial gizzard mass within 8.5 days, while switches to hard food induced increases in gizzard mass to 147% within 6.2 days. A third group of knots (N=11), adapted to soft food for more than 1 year, initially had very small gizzards (25% of the mass of shellfish-adapted gizzards), but showed a similar capacity to increase gizzard size when fed shellfish. This is the first non-i...
We studied phenology, staging time and refuelling in Broad-billed Sandpipers Limicola falcinellus... more We studied phenology, staging time and refuelling in Broad-billed Sandpipers Limicola falcinellus stopping over during spring migration in the Sivash (Black Sea, Ukraine) in May 1991–94. In the study area, peak staging numbers of 2000–2500 individuals occurred in the third week of May. In May 1993, 460 birds were marked with a yellow dye and 126 of these were colour-ringed. Before 28 May no departure of birds dyed yellow could be detected; by 3 June all birds had departed. Colour-ringed adults in mid May 1993 staged for a ...
Uploads
Papers by Anita Koolhaas