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Bebauungsplaene Eppelborn/Eppelborn - Auf_der_Kepp_II_Teil

Bebauungspläne und Umringe der Gemeinde Eppelborn Ortsteil Eppelborn (Saarland):Bebauungsplan "Auf_der_Kepp_II_Teil" der Gemeinde Eppelborn, Ortsteil Eppelborn

Measurements of bending properties of kelp, Laminaria hyperborea, Heligoland, Germany

The flexural rigidity and bending modulus of kelp, Laminaria hyperborea, collected at the MarGate area (https://www.awi.de/en/science/special-groups/scientific-diving/margate.html) north of Heligoland, Germany (latitude: 54° 11.700'N, longitude: 7° 52.600'E) was determined from measurements performed at the Alfred Wegener Institute (AWI) Helmholtz Centre for Polar and Marine Research. Scientific divers from the Biological Institute Helgoland, AWI, collected nine kelps (Laminaria hyperborea) from the MarGate area on 21.06.2022. The collected kelps were transported into the laboratory in boxes filled with seawater from the site and stored in laboratory sinks filled with running aerated seawater from the North Sea during the experiments. The measurements were carried out on 23.06.2022, 25.06.2022, and 27.06.2022. They consisted of cutting strips 20 cm in length (L) and 2.5 cm in width (b) from the blades close to the stipe of each kelp. The cut-out strips were towel-dried, and their thickness (t, mm) and weight in grams were measured. The weight in grams was converted to weight per unit area (w, N/m²) to compute the flexural rigidity per unit width (J, Nm). A standard ruler with precision for the nearest millimeter was used to measure the length (L), width (b), and cantilever length (l) of strips. The thickness (t) of the strip was measured with a caliper gauge that measured to the nearest 0.01 millimeter. The weight of the strip was measured by a weighing scale (Sartorius, LE323S), which had a precision of 0.001 grams. The cut-out strips from each kelp form the nine samples tested for the bending properties. Each sample is used to repeat the cantilever test four times, i.e., both sides' ends, as Henry (2014) recommended to improve the accuracy. An apparatus consisting of two planes, one angled at 45° (θ = 45°) and the other parallel to the horizontal, was used for the test. The device was clamped onto a table on the horizontal plane. The experimental protocol consists of laying each strip onto the apparatus with the strip's edge coinciding with the apparatus's angled edge. After that, the strip is slowly moved forward with a ruler, with the ruler's zero coinciding with the strip's edge. This is done until the tip of the strip touches the inclined plane. The horizontal projection of the length of the hanging strip is equal to the distance between the ruler's tip and the apparatus's angle, termed the cantilever length (l). The flexural rigidity per unit width (J, Nm) and the bending modulus (Eb, N/m²) are then calculated with the second moment of area (I, m⁴) as in Henry (2014).

Summer heatwave impacts on the European kelp Saccharina latissima across its latitudinal distribution gradient – raw data to temperature-amplitude experiment with field material from five different locations

Temperature is a major factor for the global biogeographic pattern of marine benthic algal species and their loss has serious consequences for ecosystems. Local adaptation and phenotypic plasticity of species can result in intraspecific differences of thermal tolerance, and population loss might not only occur at thermal trailing edges. Understanding the underlying physiological and biochemical response mechanisms is from major importance. Therefore, we run the same short-term experiment with field sporophytes of Saccharina latissima from five locations along the European coast (Spitsbergen, Bodø, Bergen, Helgoland, Locmariaquer). We increased each respective mean summer temperature (control, ±0°C) by +2, +4 and +6°C to mimic realistic local heatwave events. The maximum photosynthetic quantum yield of photosystem II (Fv/Fm; Imaging-PAM, Walz GmbH Mess- und Regeltechnik, Effeltrich, Germany) was monitored every day. For growth, the size of the algal discs was photographed every second day, analyzed with ImageJ (Version 1.52a). Absolute concentrations of all pigments were analyzed using a HPLC. Afterwards, the pool sizes, the de-epoxidation state of the xanthophyll cycle (DPS), and the ratios were calculated. The C:N ratio, total nitrogen and total carbon content were analyzed with an elemental analyzer. Mannitol concentration was also analyzed in a HPLC. Phlorotannins were analyzed using the photometric Folin-Ciocalteu method.

Laminaria digitata gametophyte survival and microscopic sporophyte formation, abundance and growth during exposure to decreased temperatures

To assess the thermal adaptation of microscopic stages of the kelp Laminaria digitata along latitudes, we conducted laboratory experiments on samples from six locations in the NE Atlantic (Spitsbergen (SPT), Tromsø (TRM), Bodø (BOD; all Norway), Helgoland (HLG; Germany), Roscoff (ROS) and Quiberon (QUI; both France)), spanning the species' entire distribution range. Gametophyte stock cultures from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research were used. Prior to the experiments, cultures were stored at 15°C in iron-free ½ Provasoli enriched seawater in 3-4 µmol photons/m²/s red light. In experiment 2, samples were subjected to (sub-) optimal low temperatures (0-15°C) for 21 days, to assess gametophyte survival, sporophyte formation and growth. During the experiments, samples were kept in 15 µmol photons/m²/s white light under a 16:8h light:dark cycle. Sporophyte growth rates both in length and in width were determined as follows: GR = (x2-x1)/(t2-t1), where x is the length or width (μm) and t is the time in weeks at time point 1 and 2.

Laminaria digitata gametophyte survival and sporophyte formation during exposure to increased temperatures

To assess the thermal adaptation of microscopic stages of the kelp Laminaria digitata along latitudes, we conducted laboratory experiments on samples from six locations in the NE Atlantic (Spitsbergen (SPT), Tromsø (TRM), Bodø (BOD; all Norway), Helgoland (HLG; Germany), Roscoff (ROS) and Quiberon (QUI; both France)), spanning the species' entire distribution range. Gametophyte stock cultures from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research were used. Prior to the experiments, cultures were stored at 15°C in iron-free ½ Provasoli enriched seawater in 3-4 µmol photons/m²/s red light. In experiment 1, we exposed gametophytes to (sub-) lethal high priming temperatures (20-25°C) for two weeks, followed by two weeks of recovery at 15°C, to observe gametophyte survival and sporophyte formation. During the experiments, samples were kept in 15 µmol photons/m²/s white light under a 16:8h light:dark cycle.

Integrated survival of Laminaria digitata gametophytes exposed to increased temperatures

To assess the thermal adaptation of microscopic stages of the kelp Laminaria digitata along latitudes, we conducted laboratory experiments on samples from six locations in the NE Atlantic (Spitsbergen (SPT), Tromsø (TRM), Bodø (BOD; all Norway), Helgoland (HLG; Germany), Roscoff (ROS) and Quiberon (QUI; both France)), spanning the species' entire distribution range. Gametophyte stock cultures from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research were used. Prior to the experiments, cultures were stored at 15°C in iron-free ½ Provasoli enriched seawater in 3-4 µmol photons/m²/s red light. In experiment 1, we exposed gametophytes to (sub-) lethal high priming temperatures (20-25°C) for two weeks, followed by two weeks of recovery at 15°C, to observe gametophyte survival and sporophyte formation. During the experiments, samples were kept in 15 µmol photons/m²/s white light under a 16:8h light:dark cycle.

Local adaptation of microscopic stages of North Atlantic Laminaria digitata to high and low temperatures along latitudes: survival, reproduction and growth

To assess the thermal adaptation of microscopic stages of the kelp Laminaria digitata along latitudes, we conducted laboratory experiments on samples from six locations in the NE Atlantic (Spitsbergen (SPT), Tromsø (TRM), Bodø (BOD; all Norway), Helgoland (HLG; Germany), Roscoff (ROS) and Quiberon (QUI; both France)), spanning the species' entire distribution range. In experiment 1, we exposed gametophytes to (sub-) lethal high priming temperatures (20-25°C) for two weeks, followed by two weeks of recovery at 15°C, to observe gametophyte survival and sporophyte formation. In experiment 2, samples were subjected to (sub-) optimal low temperatures (0-15°C) for 21 days, to assess gametophyte survival, sporophyte formation and growth. During the experiments, samples were kept in 15 µmol photons/m²/s white light under a 16:8h light:dark cycle. Prior to the experiments, cultures were stored at 15°C in iron-free ½ Provasoli enriched seawater in 3-4 µmol photons/m²/s red light.

Information on Laminaria hyperborea samples off the island of Helgoland in summer 2014

Laminaria hyperborea off the island of Helgoland (North Sea, Germany) was sampled along a depth gradient (0.5, 2, 4, 6 m) throughout summer 2014. Stipe length of the sporophyte was measured. In blade discs from three different blade regions (5, 25 and 50 cm above the stipe-blade transition zone) dry mass, fresh mass and dry mass:area ratio were measured.

Photosynthetically active radiation measured in different water depths near the island of Helgoland in summer 2014

In-situ photosynetically active radiation (PAR) was measured in different depths (1.2, 2.9, 4.4, 6.6 m) every 10-15 min during summer 2014. Odyssey PAR loggers were calibrated against a cosine-corrected planar PAR sensor (LI-190SA quantum sensor, LI-COR Inc., USA) over a 24 h period at 4 m depth in the Helgolandic South harbor. During the Laminaria hyperborea sampling period (seven weeks), incoming PAR was recorded continuously every 15 min at 1.2 and 2.9 m, and every 30 min at 4.4 and 6.6 m near the sampling area of sporophytes. To avoid biofouling of the sensor heads, PAR loggers were cleaned every week (1.2 m) or every second week (all other depths) by SCUBA divers.

Chlorophyll a content of Laminaria hyperborea off the island of Helgoland in summer 2014

Laminaria hyperborea off the island of Helgoland (North Sea, Germany) was sampled along a depth gradient (0.5, 2, 4, 6 m) throughout summer 2014. Chlorophyll a content was measured. Discs were cut from three different blade regions (5, 25 and 50 cm above the stipe-blade transition zone) and normalized to either dry mass, fresh mass or disc area. The samples were freeze-dried for approximately 36 h (Beta 1–8 LDplus, Christ, Osterode am Harz, Germany), finely ground for several minutes using steel grinding balls (3 mm diameter) in a Mikro-Dismembrator U (Braun Biontech International, Melsungen, Germany), cooled centrifuged (Centrifuge 3K10, Sigma, Osterode, Germany), and measured in the spectrophotometer (U-3310, Hitachi High-Tech, Japan) at two wavelengths (347 and 664.5 nm).

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