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Author Langbehn, T.; Aksnes, D.; Kaartvedt, S.; Fiksen, Ø.; Jørgensen, C.
Title Light comfort zone in a mesopelagic fish emerges from adaptive behaviour along a latitudinal gradient Type Journal Article
Year 2019 Publication Marine Ecology Progress Series Abbreviated Journal Mar. Ecol. Prog. Ser.
Volume (down) 623 Issue Pages 161-174
Keywords Animals; Moonlight
Abstract Throughout the oceans, small fish and other micronekton migrate between daytimedepths of several hundred meters and near-surface waters at night. These diel vertical migrationsof mesopelagic organisms structure pelagic ecosystems through trophic interactions, and are akey element in the biological carbon pump. However, depth distributions and migration ampli-tude vary greatly. Suggested proximate causes of the migration such as oxygen, temperature, andlight often correlate and therefore the causal underpinnings have remained unclear. Using meso-pelagic fishes and the Norwegian Sea as a study system, we developed a dynamic state variablemodel that finds optimal migration patterns that we validate with acoustic observations along alatitudinal gradient. The model describes predation risk and bioenergetics, and maximizes ex -pected energy surplus, a proxy for Darwinian fitness. The model allows us to disentangle the driv-ers of migration and make predictions about depth distribution and related fitness consequencesalong a latitudinal trajectory with strong gradients in environmental drivers and vertical distribu-tion of scattering layers. We show that the model-predicted vertical migration of mesopelagicfishes matches that observed along this transect. For most situations, modelled mesopelagic fishbehaviour can be well described by a light comfort zone near identical to that derived from obser-vations. By selectively keeping light or temperature constant, the model reveals that temperature,in comparison with light, has little effect on depth distribution. We find that water clarity, whichlimits how deeply light can penetrate into the ocean, structures daytime depths, while surfacelight at night controlled the depth of nocturnal ascents.
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ISSN 0171-8630 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 2598
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Author Maggi, E.; Benedetti-Cecchi, L.
Title Trophic compensation stabilizes marine primary producers exposed to artificial light at night Type Journal Article
Year 2018 Publication Marine Ecology Progress Series Abbreviated Journal Mar. Ecol. Prog. Ser.
Volume (down) 606 Issue Pages 1-5
Keywords Plants; Animals; Ecology
Abstract Artificial light at night (ALAN) is a widespread phenomenon along coastal areas. Despite increasing evidence of pervasive effects of ALAN on patterns of species distribution and abundance, the potential of this emerging threat to alter ecological processes in marine ecosystems has remained largely unexplored. Here, we show how exposure to white LED lighting, comparable to that experienced along local urbanized coasts, significantly enhanced the impact of grazing gastropods on epilithic microphytobenthos (MPB). ALAN increased both the photosynthetic biomass of MPB and the grazing pressure of gastropods, such that consumers compensated for the positive effect of night lighting on primary producers. Our results indicate that trophic interactions can provide a stabilizing compensatory mechanism against ALAN effects in natural food webs.
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ISSN 0171-8630 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2063
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Author Wilson, P.; Thums, M.; Pattiaratchi, C.; Meekan, M.; Pendoley, K.; Fisher, R.; Whiting, S.
Title Artificial light disrupts the nearshore dispersal of neonate flatback turtles Natator depressus Type Journal Article
Year 2018 Publication Marine Ecology Progress Series Abbreviated Journal Mar. Ecol. Prog. Ser.
Volume (down) 600 Issue Pages 179-192
Keywords Animals
Abstract After emerging from nests, neonate sea turtles entering the water are thought to orientate away from shore using wave cues to guide them out to sea. Artificial light may interfere with this process, but the relative importance of natural and anthropogenic cues to the dispersal of hatchlings is unknown. Here, we used acoustic telemetry to track the movement of flatback turtle (Natator depressus) hatchlings dispersing through nearshore waters. Turtles dispersed in the presence and absence of artificial light through a receiver array where a range of oceanographic variables were measured. Turtle tracks were analysed using a full subsets Generalised Additive Mixed Model approach to identify the most important cues influencing the bearing, variance in bearing (a measure of the ability to orientate directly), rate of travel and time spent in the array. Artificial light reduced their swim speed by up to 30%, increased the amount of time spent in nearshore waters (by 50–150%) and increased the variance in bearing (100–180% more variable), regardless of oceanographic conditions. Under ambient conditions, ocean currents affected the bearing of hatchlings as they left the shore, but when light was present, this effect was diminished, showing turtles actively swam against currents in their attempts to move towards light. After accounting for the effects of currents on hatchlings dispersing under ambient conditions, turtles swam offshore by moving perpendicular to the coastline and did not appear to orient into incident wave direction. Overall, light disrupted the dispersal of hatchlings causing them to linger, become disoriented in the near shore and expend energy swimming against ocean currents.
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ISSN 0171-8630 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1967
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Author Pendoley, K.; Kamrowski, R.
Title Influence of horizon elevation on the sea-finding behaviour of hatchling flatback turtles exposed to artificial light glow Type Journal Article
Year 2015 Publication Marine Ecology Progress Series Abbreviated Journal Mar. Ecol. Prog. Ser.
Volume (down) 529 Issue Pages 279-288
Keywords Animals; Hatchling orientation; Artificial lighting; Horizon elevation; Marine turtle; Conservation management; Elevation; Industry; Coastal development; Sea turtle; Sea turtle conservation
Abstract Marine turtles are threatened globally by increasing coastal development. In particular, increased artificial lighting at the nesting beach has the potential to disrupt turtle breeding success. Few published data exist regarding the behaviour of the flatback turtle Natator depressus, a species endemic to Australia, in response to artificial light. Given the ongoing industrialisation of the Australian coastline, this study is a timely investigation into the orientation of flatback hatchlings exposed to light glow produced by lighting typically used in industrial settings. We recorded the orientation of hatchlings at the nesting beach on Barrow Island, Western Australia, exposed to 3 types of standard lighting — high-pressure sodium vapour (HPS), metal halide (MH), and fluorescent white (FW)—at 3 different intensities. The light array was positioned either behind a high dune (producing a high, dark silhouette; 16° elevation), or in a low creek bed (producing a low silhouette and bright horizon; 2° elevation). At medium and high light intensities of all 3 light types, hatchlings were significantly less ocean-oriented when exposed to light at 2° elevation compared to 16° elevation. This difference remained with glow from low-intensity MH light; however, there was no significant difference in orientation of hatchlings exposed to low- intensity HPS and FW light glow at either elevation. Our study emphasises the importance of horizon elevation cues in hatchling sea-finding. Since all species of marine turtles show similar sea-finding behaviour, our results have important implications for management of lighting adjacent to turtle nesting beaches in Australia and elsewhere, as coastal development continues.
Address Pendoley Environmental Pty Ltd, 12A Pitt Way, Booragoon, Western Australia 6154, Australia; ruth.kamrowski@penv.com.au
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Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0171-8630 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1189
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Author Cruz, L.M.; Shillinger, G.L.; Robinson, N.J.; Tomillo, P.S.; Paladino, F.V.
Title Effect of light intensity and wavelength on the in-water orientation of olive ridley turtle hatchlings Type Journal Article
Year 2018 Publication Journal of Experimental Marine Biology and Ecology Abbreviated Journal Journal of Experimental Marine Biology and Ecology
Volume (down) 505 Issue Pages 52-56
Keywords Animals
Abstract Light pollution, associated with coastal development, poses a growing threat to sea turtles. Hatchlings are particularly affected during their crawl to the ocean since they exhibit phototaxis and may move towards or be disoriented by artificial lights. Although much is known about how hatchlings respond to artificial light while crawling to the ocean, far less is known about their response after reaching the water. Here, we investigate how hatchling olive ridley turtles (Lepidochelys olivacea) held in artificial pools responded to light of different wavelengths (red, 720 nm; yellow, 660 nm and green, 520 nm) and intensities (0.1–3.3 lx, mean 0.87 lx, SD = 0.85, 10.3–45.9 lx, mean 15.75 lx,SD = 7.12; 47.5–84.2 lx; mean 52.02 lx, SD = 9.11; 91.3–140.8 lx, mean 105 lx, SD = 13.24; 150.1–623 lx, mean 172.18 lx, SD = 73.42). When no light or red light below 39 lx was present, hatchlings oriented at a mean angle of 180° from true north and did not orient towards any discernable feature. However, hatchlings swam towards the light at intensities of red light above 39 lx, yellow light above 10 lx and green light above 5 lx. Our findings indicate that sea turtles will swim towards artificial lights even after reaching the water. Thus, we recommend light mitigation efforts should extend beyond nesting beaches and into the associated oceanic habitats.
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ISSN 0022-0981 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1894
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