API src

Found 8 results.

Other language confidence: 0.9876870260421444

Effect of food limitation and temperature on survival and development of Hemigrapsus sanguineus first stage larvae

This is a laboratory experiment, carried out in Helgoland to explore how responses to the time scale and magnitude of fluctuations in environmental variables depend on the choice of time reference frame. The experiment consisted of exposing larvae of an intertidal invertebrate, Hemigrapsus sanguineus to different initial feeding periods (in days; food = freshly hatched Artemia sp Nauplii provided ad libitum), followed by a period without food. An ovigerous female of H. sanguineus was collected by hand in the intertidal of Helgoland (SW beach: “Kringel”; coordinates: 54.177323°N, 7.885273°E) during low tide on the 15th October 2020. It was kept until larval hatching in an aquarium (vol = 2 L with a shelter) at salinity = 32 ppt, temperature = 18°C, photoperiod 12:12, permanent oxygenation and fed every second day (from frozen shrimp); water was changed every day. Experiments started on date 31st October 2020 (day 0 of the feeding period). The feeding protocol was carried out with groups of freshly hatched zoea I larvae (3 replicates of 10 larvae each) at 4 temperatures (15, 17, 19, 21°C). Larvae were reared at salinity = 32 ppt. The response variables were developmental time (in days) and the number of larvae reaching the second zoeal stage. Additional columns provide calculations of the average duration of development depending on temperature and the proportion of feeding time given as a proportion of the full developmental time.

Experimental study on common starfish Asterias rubens to heatwaves and hypoxic upwelling: measured abiotics

Experimental study on the performance of the common starfish Asterias rubens subjected to heatwaves of different duration and amplitude (No, Present-day, Extended, Amplified and Amplified & Extended heatwave) followed by a hypoxic upwelling. The study was conducted at GEOMAR, Helmholtz-Centre for Ocean Research Kiel (54.329979 N, 10.148013 E) in the Indoor Benthocosms (Pansch and Hiebenthal 2019) over 63 days from July 10th until September 10th, 2018. The implemented treatments are based on a climatological analysis of a 15-year long data set (Pansch et al. 2018). The temperature was measured over the entire experimental period (TTX 110 type T, Ebro, Ingolstadt, Germany). Salinity, pH, and oxygen concentration were measured along with the simulated upwelling event (Multi 3630 IDS, WTW, Kaiserslautern, Germany).

Experimental study on common starfish Asterias rubens to heatwaves and hypoxic upwelling: survival

Experimental study on the performance of the common starfish Asterias rubens subjected to heatwaves of different duration and amplitude (No, Present-day, Extended, Amplified and Amplified & Extended heatwave) followed by a hypoxic upwelling. The study was conducted at GEOMAR, Helmholtz-Centre for Ocean Research Kiel (54.329979 N, 10.148013 E) in the Indoor Benthocosms (Pansch and Hiebenthal 2019) over 63 days from July 10th until September 10th, 2018. The implemented treatments are based on a climatological analysis of a 15-year long data set (Pansch et al. 2018). Starfish survival was checked every three days of the experiment.

Experimental study on common starfish Asterias rubens to heatwaves and hypoxic upwelling: implemented treatments

Experimental study on the performance of the common starfish Asterias rubens subjected to heatwaves of different duration and amplitude (No, Present-day, Extended, Amplified and Amplified & Extended heatwave) followed by a hypoxic upwelling. The study was conducted at GEOMAR, Helmholtz-Centre for Ocean Research Kiel (54.329979 N, 10.148013 E) in the Indoor Benthocosms (Pansch and Hiebenthal 2019) over 63 days from July 10th until September 10th, 2018. The implemented treatments are based on a climatological analysis of a 15-year long data set (Pansch et al. 2018). The temperature was measured over the entire experimental period (TTX 110 type T, Ebro, Ingolstadt, Germany).

Experimental study on common starfish Asterias rubens to heatwaves and hypoxic upwelling: feeding rate

Experimental study on the performance of the common starfish Asterias rubens subjected to heatwaves of different duration and amplitude (No, Present-day, Extended, Amplified and Amplified & Extended heatwave) followed by a hypoxic upwelling. The study was conducted at GEOMAR, Helmholtz-Centre for Ocean Research Kiel (54.329979 N, 10.148013 E) in the Indoor Benthocosms (Pansch and Hiebenthal 2019) over 63 days from July 10th until September 10th, 2018. The implemented treatments are based on a climatological analysis of a 15-year long data set (Pansch et al. 2018). Starfish feeding rate was quantified by measuring the shell length of consumed blue mussels (Dial Caliper DialMax Metric, Wiha Division KWB Switzerland).

Experimental study on common starfish Asterias rubens to heatwaves and hypoxic upwelling: wet weight

Experimental study on the performance of the common starfish Asterias rubens subjected to heatwaves of different duration and amplitude (No, Present-day, Extended, Amplified and Amplified & Extended heatwave) followed by a hypoxic upwelling. The study was conducted at GEOMAR, Helmholtz-Centre for Ocean Research Kiel (54.329979 N, 10.148013 E) in the Indoor Benthocosms (Pansch and Hiebenthal 2019) over 63 days from July 10th until September 10th, 2018. The implemented treatments are based on a climatological analysis of a 15-year long data set (Pansch et al. 2018). Starfish individuals were weighed at the start of the experiment, during the heatwaves, in between heatwaves and the upwelling event, directly after the upwelling event and at the end of the experiment.

Experimental study on common starfish Asterias rubens to heatwaves and hypoxic upwelling: righting time

Experimental study on the performance of the common starfish Asterias rubens subjected to heatwaves of different duration and amplitude (No, Present-day, Extended, Amplified and Amplified & Extended heatwave) followed by a hypoxic upwelling. The study was conducted at GEOMAR, Helmholtz-Centre for Ocean Research Kiel (54.329979 N, 10.148013 E) in the Indoor Benthocosms (Pansch and Hiebenthal 2019) over 63 days from July 10th until September 10th, 2018. The implemented treatments are based on a climatological analysis of a 15-year long data set (Pansch et al. 2018). Starfish activity was measured as righting response (i.e., time needed for the starfish to turn back onto their oral side after being placed on their aboral side) before the beginning of the heatwave treatments, at the end of the heatwaves, before, during and at the end of the upwelling event, and at the end of the experiment.

Experimental study on common starfish Asterias rubens to heatwaves and hypoxic upwelling

Experimental study on the performance of the common starfish Asterias rubens subjected to heatwaves of different duration and amplitude (No, Present-day, Extended, Amplified and Amplified & Extended heatwave) followed by a hypoxic upwelling. The study was conducted at GEOMAR, Helmholtz-Centre for Ocean Research Kiel (54.329979 N, 10.148013 E) in the Indoor Benthocosms (Pansch and Hiebenthal 2019) over 63 days from July 10th until September 10th, 2018. The implemented treatments are based on a climatological analysis of a 15-year long data set (Pansch et al. 2018). The temperature was measured over the entire experimental period (TTX 110 type T, Ebro, Ingolstadt, Germany). Salinity, pH, and oxygen concentration were measured along with the simulated upwelling event (Multi 3630 IDS, WTW, Kaiserslautern, Germany). Starfish feeding rate was quantified by measuring the shell length of consumed blue mussels (Dial Caliper DialMax Metric, Wiha Division KWB Switzerland). Based on a previously described relationship between shell size and tissue dry weight for mussels in the study area (Moron et al. 2020), the dry weight of consumed mussels was estimated. Starfish individuals were weighed at the start of the experiment, during the heatwaves, in between heatwaves and the upwelling event, directly after the upwelling event and at the end of the experiment. Starfish activity was measured as righting response (i.e., time needed for the starfish to turn back onto their oral side after being placed on their aboral side) before the beginning of the heatwave treatments, at the end of the heatwaves, before, during and at the end of the upwelling event, and at the end of the experiment.

1