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Sulfur in lucinid bivalves inhibits intake rates of a molluscivore shorebird
No full textA forager?s energy intake rate is usually constrained by a combination of handling time, encounter rate and digestion rate. On top of that, food intake may be constrained when a forager can only process a maximum amount of certain toxic compounds. The latter constraint is well described for herbivores with a limited tolerance to plant secondary metabolites. In sulfidic marine ecosystems, many animals host chemoautotrophic endosymbionts, which store sulfur compounds as an energy resource, potentially making their hosts toxic to predators. The red knot Calidris canutus canutus is a molluscivore shorebird that winters on the mudflats of Banc d?Arguin, where the most abundant bivalve prey Loripes orbiculatus hosts sulfide-oxidizing bacteria. In this system, we studied the potential effect of sulfur on the red knots? intake rates, by offering Loripes with various sulfur content to captive birds. To manipulate toxicity, we starved Loripes for 10 days by removing them from their symbiont?s energy source sulfide. As predicted, we found lower sulfur concentrations in starved Loripes. We also included natural variation in sulfur concentrations by offering Loripes collected at two different locations. In both cases lower sulfur levels in Loripes resulted in higher consumption rates in red knots. Over time the red knots increased their intake rates on Loripes, showing their ability to adjust to a higher intake of sulfur
Simple and complex burrow morphology in two Macrophthalmus species on the intertidal mudflats of Barr Al Hikman, Sultanate of Oman
No full textBurrowing Ocypodoidea crabs are an abundant component of many tropical and temperate coastal areas and central to the ecosystem functioning, for instance because they recycle nutrients, are important food for many shorebirds and alter the sediment by their burrowing behaviour. The burrow morphology of these crabs may differ between and within species, often correlated with differences in habitat preferences, crab morphology and life-history traits. Here we studied the burrow morphology and complexity of Macrophthalmus sulcatus and Macrophthalmus depressus, by means of casts (n = 7 and 10 respectively) and burrow excavations (n = 17 and 16 respectively) at the pristine intertidal mudflats of Barr Al Hikman in the Sultanate of Oman. We found that M. sulcatus construct simple burrows that were in all but one case inhabited by a single crab. By contrast, all burrows of M. depressus were complex with multiple entrances and many (deep-reaching) branches. There was a strong relation between M. sulcatus carapace width and burrow entrance size, indicating that the simple burrows are adapted to, and made by the occupant. There was no relation between M. depressus carapace width and burrow entrance size, and in six burrows more than one crab was encountered, suggesting that the complex burrows are not made by, and adapted to a single occupant. The complex burrows were found close to the shore whereas the simple burrows were found at the intermediate tidal zone. We speculate that the striking differences in burrow morphology may be explained by difference in habitat selection of the studied crabs, which most importantly relates to differences in sediment structure and tidal height. Also, crab morphology and life-history traits including the social life of the studied crabs could account for the observed difference in burrow morphology
Trace Metals Amundsen Sea Araon ANA08B and Weddell Sea PS117
No full textAmundsen ANA08B: Samples were collected onboard the South Korean icebreaker RV Araon during the ANA08B research expedition to the Amundsen Sea in the austral summer of 2017/2018. The sampling period spanned from the 24th of January to the 2nd of February 2018. A total of 10 full depth stations were investigated with a maximum of 12 sampling depths. The transect followed the in- and outflow of CDW in the ASP through a trough near the Dotson ice shelf. The ASP was surrounded by sea ice at the start of the sampling campaign, whereas the polynya had started to open to the open ocean on the northwest side by the end of sampling. Along this transect, station 53 was located off the shelf and outside the polynya in the marginal sea ice zone, station 52 was located near the outermost edge of the polynya at the shelf break, stations 42 and 36 were located at the Dotson Ice Shelf front on the in -and outflow side respectively, and the remaining stations were located in the central open water body of the ASP. Water was collected with the ‘Titan’ ultraclean CTD sampling system for trace metals mounted with pristine large volume samplers. To prevent light shock of phytoplankton, the original PVDF samplers were replaced by a light-proof version of the Pristine samplers and were made from polypropylene. The salinity (conductivity), temperature, fluorescence, depth (pressure) and oxygen were measured with a CTD (Seabird SBE 911+) mounted on the trace metal clean sampling system of NIOZ. The sampling system was deployed on a 11 mm Dyneema cable without internal conductive wires and therefore an SBE 17 plus V2 Searam in a titanium housing provided power, saved the CTD data and closed the sampling bottles at pre-programmed depths. After deployment, the complete CTD sampling system was placed in a cleanroom environment inside a modified high cube shipping container and subsamples were collected.
Weddell Sea PS117: Samples were collected on board the German icebreaker RV Polarstern during the PS117 research expedition to the Weddell Sea in the austral summer of 2018/2019. The sampling period spanned from the 26th of January to the 1st of February 2019. A total of 23 (semi)full depth stations were taken with a maximum of 20 sampling depths. Samples for trace metals were collected along the prime meridian (0° W) transect in December/January 2018-2019 at 8 stations. Northernmost station 22 is located at 59°S and southernmost station 30 at 69.37° S. Additionally, 4 stations were samples near the ice sheet and in the Weddell Basin that were not along a transect. Due to the malfunctioning sampling system, deepest depths were not sampled correctly and can therefore not be used in the analysis. Along the Weddell Sea transect a total of 11 trace metal stations, of which 6 full depth, were sampled in January/February 2019. The transect starts in the Weddell Sea basin at station 61 (45.8°W) and followed the continental slope towards the West-Antarctic peninsula where the shelf station 95 was closest to the continent (54.5° W).
Water was collected with the ‘Titan’ ultraclean CTD sampling system for trace metals mounted with pristine large volume samplers. To prevent light shock of phytoplankton, the original PVDF samplers were replaced by a light-proof version of the Pristine samplers and were made from polypropylene. The salinity (conductivity), temperature, fluorescence, depth (pressure) and oxygen were measured with a CTD (Seabird SBE 911+) mounted on the trace metal clean sampling system of NIOZ. The sampling system was deployed on a 11 mm Dyneema cable without internal conductive wires and therefore an SBE 17 plus V2 Searam in a titanium housing provided power, saved the CTD data and closed the sampling bottles at pre-programmed depths. After deployment, the complete CTD sampling system was placed in a cleanroom environment inside a modified high cube shipping container and subsamples were collected
Data from: Spatial patterns in age- and colony-specific survival in a long-lived seabird across 14 contrasting colonies
No full textDemographic rates such as recruitment and survival probability can vary considerably among populations of the same species due to variation in underlying environmental processes. If environmental processes are spatially correlated, nearby populations are expected to have more similar demographic rates than those further apart. Breeding populations and foraging ranges are spatially segregated in colonial seabirds, making them ideal for studying spatial patterns in demographic rates and their effects on local population dynamics. Here we explored variation in age-dependent survival probabilities across 14 colonies of Herring Gulls Larus argentatus breeding along the Dutch North Sea coast. We used long-term mark-recapture data of marked fledglings to estimate survival, and estimated spatial autocorrelation of survival probabilities. We assessed whether survival until recruitment age or until 10-years old (close to their expected lifespan) explained variation in population trajectories of each colony. Juvenile and adult survival showed a strong, but different, north-to-south gradient in survival, probability with lower juvenile but higher adult survival in northern colonies than southern colonies, whereas the spatial pattern of immature survival was less distinct. Neither recruitment nor the proportion of 10-year-old adults alive predicted whether a colony collapsed, declined, remained stable or increased. The distinct spatial pattern in survival suggests variation in regional food availability, which do not seem to drive local population dynamics. The absence of a link between survival and colony trajectories implies that connectivity between populations plays an important role affecting population dynamics
A probabilistic framework for Windows of Opportunity: the role of temporal variability in critical transitions_supplementary material
No full textThe establishment of young organisms in harsh environments often requires a Window of Opportunity (WoO). That is, a short time window in which environmental conditions drop long enough below the hostile average level, giving the organism time to develop tolerance and transition into stable existence. It has been suggested that this kind of establishment dynamics is a noise-induced transition between two alternate states. Understanding how temporal variability (i.e., noise) in environmental conditions affects establishment of organisms is therefore key, yet not well understood or included explicitly in the WoO framework. In this paper we develop a coherent theoretical framework for understanding when WoO open or close based on simple dichotomous environmental variation. We reveal that understanding of the intrinsic time scales of both the developing organism and the environment is fundamental to predict if organisms can or cannot establish. These insights have allowed us to develop statistical laws for predicting establishment probabilities based on the period and variance of the fluctuations in naturally variable environments. Based on this framework we now get a clear understanding of how changes in the timing and magnitude of climate variability or management can mediate establishment chances
Monitoring of a sediment plume produced by a deep-sea mining test in shallow water, Malaga Bight, Alboran Sea (southwestern Mediterranean Sea) - Dataset 2019
No full textIn this study different experimental designs for monitoring of sediment plumes produced by deep-sea mining are presented. Plumes of sediment stirred up from the seabed by mining machines are considered to represent a major environmental pressure which may extend far beyond the actual mining area. Two industry field tests with the scaled mining vehicle Apollo II of Royal IHC conducted in a relatively shallow setting offshore southern Spain provided valuable insights for anticipated monitoring of nodule mining activities in the deep Pacific. Although the tests were performed in only 300 m water depth, much less than the depth where future deep-sea mining will take place, the weakly stratified bottom water, tide-dominated near-bed currents with mean magnitude of around 5-10 cm s-1, and gently sloping seabed covered with fine muddy sediment provide a good analogue to operational conditions in the deep sea. The plume of suspended sediment mobilised by the mining vehicle was monitored with turbidity sensors deployed on a ship-operated CTD system and on a static array of moored sensors and monitored visually using a ship-operated ROV. It was found that the generated sediment plume extended not more than 2 m above the seabed close to the source (<100 m) but increased in height at greater distance. Furthermore, turbidity values decreased rapidly with increasing distance to the source. Even though plume monitoring suffered interference from bottom trawling activities in neighbouring areas, a distinct turbidity signal generated by the mining equipment could still be distinguished above background turbidity at 350 m away from the source. From the experience gained in shallow water, recommendations are made on how a combination of sensors operated from moving and moored platforms may be a suitable and successful strategy for monitoring man-made sediment plumes in the deep sea
Coralreef imagery Curacao 1973 (I-10)
No full textThis dataset covers the imagery from 1973 for transect I at 10 m water depth, as part of the long term monitoring program on coral reef dynamics in Curacao coastal waters (Rolf Bak, Erik Meesters & Andreas Haas).
B&W negatives (Kodak Tri-X) were scanned with Epson Perfection V850 Pro scanner at a resolution of 2400 dpi and saved in tif format
NIOZ jetty hourly data for temperature and salinity for 2021
No full textNIOZ jetty LON=4.789E LAT=53.002N, using EXO sensor at depth of -1.5 meter NAP. Derived product from 10 second calibrated data. Separate calibration measurement at 2 week intervals
Monitoring of a sediment plume produced by a deep-sea mining test in shallow water, Malaga Bight, Alboran Sea (southwestern Mediterranean Sea) - Dataset 2018
No full textIn this study different experimental designs for monitoring of sediment plumes produced by deep-sea mining are presented. Plumes of sediment stirred up from the seabed by mining machines are considered to represent a major environmental pressure which may extend far beyond the actual mining area. Two industry field tests with the scaled mining vehicle Apollo II of Royal IHC conducted in a relatively shallow setting offshore southern Spain provided valuable insights for anticipated monitoring of nodule mining activities in the deep Pacific. Although the tests were performed in only 300 m water depth, much less than the depth where future deep-sea mining will take place, the weakly stratified bottom water, tide-dominated near-bed currents with mean magnitude of around 5-10 cm s-1, and gently sloping seabed covered with fine muddy sediment provide a good analogue to operational conditions in the deep sea. The plume of suspended sediment mobilised by the mining vehicle was monitored with turbidity sensors deployed on a ship-operated CTD system and on a static array of moored sensors and monitored visually using a ship-operated ROV. It was found that the generated sediment plume extended not more than 2 m above the seabed close to the source (<100 m) but increased in height at greater distance. Furthermore, turbidity values decreased rapidly with increasing distance to the source. Even though plume monitoring suffered interference from bottom trawling activities in neighbouring areas, a distinct turbidity signal generated by the mining equipment could still be distinguished above background turbidity at 350 m away from the source. From the experience gained in shallow water, recommendations are made on how a combination of sensors operated from moving and moored platforms may be a suitable and successful strategy for monitoring man-made sediment plumes in the deep sea
NIOZ jetty hourly data for temperature and salinity for 2008
No full textNIOZ jetty LON=4.789E LAT=53.002N, using EXO sensor at depth of -1.5 meter NAP. Derived product from 10 second calibrated data. Separate calibration measurement at 2 week intervals