scholarly journals Long-term decline of the western Pacific leatherback,Dermochelys coriacea: a globally important sea turtle population

Ecosphere ◽  
2013 ◽  
Vol 4 (2) ◽  
pp. art25 ◽  
Author(s):  
Ricardo F. Tapilatu ◽  
Peter H. Dutton ◽  
Manjula Tiwari ◽  
Thane Wibbels ◽  
Hadi V. Ferdinandus ◽  
...  
2020 ◽  
Author(s):  
Niklas Meinicke ◽  
Maria Reimi ◽  
Christina Ravelo ◽  
Nele Meckler

<p>The Western Pacific Warm Pool (WPWP) as a major source of heat and water vapor has a crucial influence on climate dynamics both in the tropics and globally. Yet, there is conflicting proxy evidence regarding the evolution of WPWP temperatures since the Miocene. On the one hand TEX<sub>86</sub> data suggest a gradual cooling by ~2℃ (O’Brian et al., 2014, Zhang et al., 2014) from the Pliocene to today, while faunal (planktonic foraminifera) sea surface temperature estimates (Dowsett, 2007) and Mg/Ca data measured in planktonic foraminifera (Wara et al., 2005) on the other hand indicate the absence of any long-term temperature trends. It has been suggested that Mg/Ca temperatures could on these time scales be biased by long-term changes of the Mg/Ca ratio of seawater (Evans et al., 2016). To test the influence of the proposed seawater changes on Mg/Ca we combined data from two independent temperature proxies, Mg/Ca and clumped isotopes, measured on two species of planktonic foraminifera from IODP Site U1488 in the central WPWP. Our study finds good agreement between both proxies thereby verifying the validity of Mg/Ca records from the WPWP and confirming the absence of a Plio-Pleistocene cooling trend for the WPWP. This finding suggests that the persistent disagreement between foraminifer-based proxies such as Mg/Ca and biomarker data might be caused by different environmental parameters being recorded in the two archives.</p><p> </p><p>References:</p><p>O’Brien CL, Foster GL, Martínez-Botí MA, Abell R, Rae JWB, Pancost RD. High sea surface temperatures in tropical warm pools during the Pliocene. Nature Geoscience. 2014;7(8):606-11.</p><p>Zhang YG, Pagani M, Liu Z. A 12-million-year temperature history of the tropical Pacific Ocean. Science. 2014;344(6179):84-7.</p><p>Dowsett H. Faunal re-evaluation of Mid-Pliocene conditions in the western equatorial Pacific. Micropaleontology. 2007;53(6):447-56.</p><p>Wara MW, Ravelo AC, Delaney ML. Permanent El Nino-like conditions during the Pliocene warm period. Science. 2005;309(5735):758-61.</p><p>Evans D, Brierley C, Raymo ME, Erez J, Müller W. Planktic foraminifera shell chemistry response to seawater chemistry: Pliocene–Pleistocene seawater Mg/Ca, temperature and sea level change. Earth and Planetary Science Letters. 2016;438:139-48.</p>


2016 ◽  
Vol 41 (1) ◽  
pp. 7-48 ◽  
Author(s):  
Stephen Biddle ◽  
Ivan Oelrich

Many analysts worry that improvements in Chinese missile, sensor, guidance, and other technologies will enable China to deny the U.S. military access to parts of the Western Pacific that the United States has long controlled. Although these “antiaccess, area denial” (A2/AD) capabilities are real, they are a geographically limited long-term threat. As both the United States and China deploy A2/AD capabilities, a new era will emerge in which the U.S. military no longer enjoys today's command of the global commons, but is still able to deny China military hegemony in the Western Pacific. In this new era, the United States will possess a sphere of influence around allied landmasses; China will maintain a sphere of influence over its own mainland; and a contested battlespace will cover much of the South and East China Seas wherein neither power enjoys wartime freedom of surface or air movement. This in turn suggests that the Chinese A2/AD threat to U.S. allies is real but more limited than often supposed. With astute U.S. choices, most U.S. allies in this new system will be imperfectly, but substantially, secure.


2007 ◽  
Vol 6 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Peter H. Dutton ◽  
Creusa Hitipeuw ◽  
Mohammad Zein ◽  
Scott R. Benson ◽  
George Petro ◽  
...  

2015 ◽  
Vol 143 (11) ◽  
pp. 4561-4577 ◽  
Author(s):  
Mei Hong ◽  
Ren Zhang ◽  
Dong Wang ◽  
Min Wang ◽  
Kefeng Liu ◽  
...  

Abstract A new dynamical–statistical forecasting model of the western Pacific subtropical high (WPSH) area index (AI) was developed, based on dynamical model reconstruction and improved self-memorization, in order to address the inaccuracy of long-term WPSH forecasts. To overcome the problem of single initial prediction values, the self-memorization function was introduced to improve the traditional reconstruction model, thereby making it more effective for describing chaotic systems, such as WPSH. Processing actual data, the reconstruction equation was used as a dynamical core to overcome the problem of employing a simple core. The resulting dynamical–statistical forecasting model for AI was used to predict the strength of long-term WPSH forecasting. Based on 17 experiments with the WPSH during normal and abnormal years, forecast results for a period of 25 days were found to be good, with a correlation coefficient of ~0.80 and a mean absolute percentage error of <8%, showing that the improved model produced satisfactory long-term forecasting results. Additional experiments for predicting the ridgeline index (RI) and the west ridge-point index (WI) were also performed to demonstrate that the developed model was effective for the complete prediction of the WPSH. Compared with the authors’ previous models and other established models of reasonable complexity, the current model shows better long-term WPSH forecasting ability than do other models, meaning that the aberrations of the subtropical high could be defined and forecast by the model.


Author(s):  
Paulo C.R. Barata ◽  
Eduardo H.S.M. Lima ◽  
Márcio Borges-Martins ◽  
Juarez T. Scalfoni ◽  
Claudio Bellini ◽  
...  

Data from several sources and original data are presented regarding sightings, strandings and incidental captures of leatherback sea turtles (Dermochelys coriacea) on the Brazilian coast in a 33 year period, from 1969 to 2001. Two of the turtles were small juveniles (curved carapace length=40 cm and approximately 85 cm) and the remaining animals with known carapace size were large juveniles or adults. The origin of leatherbacks observed in Brazil is unknown. Several colonies in South America, including a Brazilian one, in the Caribbean, in western Africa and even in eastern South Africa could be the source of these turtles. The data presented here suggest that more effort should be directed to the assessment of the impact of fishing gear and marine pollution on leatherbacks and that systematic surveys on beaches should be maintained in order to monitor long term fluctuations in stranding levels and spatial stranding patterns. Genetic studies and satellite telemetry would be helpful in clarifying the origin of leatherbacks stranded or incidentally captured on the Brazilian coast.


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