scholarly journals A global review of green turtle diet: sea surface temperature as a potential driver of omnivory levels

2020 ◽  
Vol 167 (12) ◽  
Author(s):  
Nicole Esteban ◽  
Jeanne A. Mortimer ◽  
Holly J. Stokes ◽  
Jacques-Olivier Laloë ◽  
Richard K. F. Unsworth ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Satellite Data ◽  
Green Turtle ◽  
Cold Water ◽  
Chelonia Mydas ◽  
Sea Surface ◽  
Terrestrial Plants ◽  
Site Specific ◽  
Quantitative Evidence

AbstractTo better understand dietary requirements, trophic shifts, and trophic interactions of the threatened green turtle (Chelonia mydas), we conducted a comprehensive global review and literature tabulation (177 studies) reporting diets of individuals > 25 cm carapace length. We analysed those studies involving natural sites and healthy animals that reported relative proportions of all diet components (67 studies, 89 datasets at 75 sites, 13 geographic sub-regions, 3 oceans). We compared diets by sub-region and foraging site relative to four diet components, i.e., seagrass, macroalgae, terrestrial plants (including mangroves) and animal matter. To assess sea surface temperature (SST) as an environmental driver, values were extracted from satellite data (single year) and site-specific observations (study durations) and examined relative to diet composition. Satellite data indicated that at warmer sites with temperatures > 25 °C (≥ 6 months annually), diet was predominantly herbivorous (mean = 92.97%; SE = 9.85; n = 69 datasets). At higher latitude sites and in cold-water currents with SST < 20 °C (≥ 6 months annually), dietary animal matter featured prominently (mean = 51.47%; SE = 4.84; n = 20 datasets). Site-specific observations indicated that SST had a small but significant effect on contributions of animal matter (r2 = 0.17, P =  < 0.001) and seagrass (r2 = 0.24, P =  < 0.001) but not macroalgae and terrestrial plants. Our study presents the first quantitative evidence at a global scale that temperature may be an important driver of omnivory, providing a new perspective on variations in green turtle diet, especially in light of global warming and climate change.

scholarly journals Observed and projected sea surface temperature seasonal changes in the Western English Channel from satellite data and CMIP5 multi-model ensemble

2016 ◽  
Vol 37 (6) ◽  
pp. 2831-2849 ◽  
Author(s):  
Blandine L'Hévéder ◽  
Sabrina Speich ◽  
Olivier Ragueneau ◽  
Francis Gohin ◽  
Philippe Bryère
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Satellite Data ◽  
Seasonal Changes ◽  
Sea Surface ◽  
English Channel ◽  
Model Ensemble

Spatio-temporal variability of internal waves in the Caspian Sea

2020 ◽  
Author(s):  
Olga Lavrova ◽  
Andrey Kostianoy
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Internal Waves ◽  
Satellite Data ◽  
Caspian Sea ◽  
Bottom Topography ◽  
Sea Surface ◽  
Anthropogenic Factors ◽  
Landsat 8 ◽  
The Caspian Sea

&lt;p&gt;Internal waves (IWs) are an intrinsic feature of all density stratified water bodies: oceans, seas, lakes and reservoirs. IWs occur due to various causes. Among them are tides and inertial motions, variations in atmospheric pressure and wind, underwater earthquakes, water flows over bottom topography, anthropogenic factors, etc. In coastal areas of oceans and tidal seas, &amp;#160;IWs induced by tidal currents over shelf edge predominate. Such IWs are well-studied in multiple field, laboratory and numerical experiments. However, the data on IWs in non-tidal seas, such as the Black, Baltic and Caspian Seas, are scarce. Meanwhile, our multi-year satellite observations prove IWs to be quite a characteristic hydrophysical phenomenon of the Caspian Sea. The sea is considered non-tidal because tide height does not exceed 12 cm at the coastline. And yet surface manifestations of IWs are regularly observed in satellite data, both radar and visible. The goal of our study was to reveal spatial, seasonal and interannual variability of IW surface manifestations in the Caspian Sea in the periods of 1999-2012 and 2018-2019 from the analysis of satellite data. All available satellite radar and visible data were used, that is data from ERS1/2 SAR; Envisat ASAR; Sentinel-1A,1B SAR-C; Landsat-4,5 TM; Landsat-7 ETM+; Landsat-8 OLI; Sentinel-2A,2B MSI sensors. During the year, IWs were observed from the beginning of May to mid-September. In certain years, depending on hydrometeorological conditions, such as water heating, wind field, etc., no IWs could be seen in May or September. IWs regularly occur in the east of Middle Caspian and in the northeast of South Caspian. In North Caspian, due to its shallowness and absence of pronounced stratification, IWs are not generated, at least their surface signatures cannot be found in satellite data. In the west of the sea, IWs are scarcely observed, primarily at the beginning of the summer season. IW trains propagate toward the coast, their generation sites are mainly over the depths of 50-200 m.&lt;/p&gt;&lt;p&gt;According to the available data for the studied periods, the time of the first appearance of IW signatures differs significantly from year to year. For example, in 1999 and 2000 it happened only in July.&lt;/p&gt;&lt;p&gt;Since no in situ measurements were conducted in the sites of regular IW manifestations, an attempt&amp;#160; was made to establish the dependence of IW occurrence frequency&amp;#160; on seasonal and interannual variations of sea surface temperature, an indirect indicator of the depth of the diurnal or seasonal thermocline, that is where IW were generated. Sea surface temperature was also estimated from satellite data.&lt;/p&gt;&lt;p&gt;Another issue addressed in the work was the differentiation between the sea surface signatures of IWs in the atmosphere and the sea. The Caspian Sea is known for their close similarity in spatial characteristics.&lt;/p&gt;&lt;p&gt;The work was carried out with financial support of the Russian Science Foundation grant #19-77-20060.&amp;#160; Processing of satellite data was carried out by Center for Collective Use &amp;#8220;IKI-Monitoring&amp;#8221; with the use of &amp;#8220;See The Sea&amp;#8221; system, that was implemented in frame of Theme &amp;#8220;Monitoring&amp;#8221;, State register No. 01.20.0.2.00164.&lt;/p&gt;

Temperature conditions of development juvenile NEA cod in the Barents sea for 1998-2015 on the basis of satellite data

2020 ◽  
Author(s):  
George Vanyushin ◽  
Tatyana Bulatova
Keyword(s):  
Life Cycle ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Satellite Data ◽  
Barents Sea ◽  
Sea Surface ◽  
Arctic Cod ◽  
Norwegian Sea ◽  
Temperature Conditions ◽  
The Barents Sea

&lt;p&gt;&lt;strong&gt;Temperature conditions of development juvenile NEA cod in the Barents sea for 1998-2015 on the basis of satellite data&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Vanyushin G. P., Bulatova T. V.&lt;/p&gt;&lt;p&gt;Russian Federal Research Institute of Fisheries and Oceanography (VNIRO)&lt;/p&gt;&lt;p&gt;107140 17, V. Krasnoselskaya str., Moscow&lt;/p&gt;&lt;p&gt;tel: 8(499)264-01-33, fax: 8(499)264-91-87,&lt;/p&gt;&lt;p&gt;e-mail: [email protected]&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Abstract&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;The paper considers the real temperature conditions in the main spawning area of North-East Arctic cod in the Norwegian sea and the development of its juveniles in the Barents sea in the periods from March to October 1998-2015. Here was taken as a principle the analysis of materials Bank mean weekly maps of sea surface temperature (SST) built on complex process: infrared digital data from metrological satellites of the series &quot;NOAA&quot; and quasisynchronous temperature data &quot;in situ&quot; from ships, buoys and coastal stations. A continuous series of indicators on temperature variability in the surface layer of sea water in coastal zone of the Norwegian sea during spawning periods and later on during the early ontogenesis of juvenile cod in the Barents sea &amp;#160;allowed to establish the dynamics of interannual seasonal temperature trends on a mesoscale period of time (1998-2015). This made it possible to assess the indirect impact of temperature conditions on the prospect of survival and, accordingly, the number of juvenile cod in the first year of its life after spawning &amp;#8211; the most important stage in the life cycle of a new generation of cod. The paper presents calculations of monthly and seasonal average values of SST and SST anomalies in the Norwegian and Barents seas, shows the interannual seasonal dynamics of these characteristics. Given for these years, the results of the comparative analysis between: seasonal values of temperature in the water surrounding the Lofoten Islands (March-April &amp;#8211; time of the main spawning) and in the water of the Barents sea (May-October - time of the early onthogenesis of juvenile cod) and professional expert estimates the number of yearlings cod. The relationship between these statistical data was positive and about equal to R= + 0,67. Information on the number of generations of cod at different stages of its life cycle was taken from the annual reports of the Arctic Fisheries Working Group ICES.&lt;/p&gt;&lt;p&gt;Keywords: satellite monitoring, sea surface temperature (SST), the&amp;#160; Northeast Arctic cod, main spawning and habitat waters, yearlings of the cod.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document