scholarly journals Potential feminization of Red Sea turtle hatchlings as indicated by in situ sand temperature profiles

2020 ◽  
Vol 2 (10) ◽  
Author(s):  
Lyndsey K. Tanabe ◽  
Joanne Ellis ◽  
Islam Elsadek ◽  
Michael L. Berumen
Keyword(s):  
Red Sea ◽  
Sea Turtle ◽  
Temperature Profiles ◽  
Sand Temperature

Factors that control the emergence of green turtle hatchlings from the nest

1993 ◽  
Vol 20 (3) ◽  
pp. 345 ◽  
Author(s):  
E Gyuris
Keyword(s):  
Temperature Gradient ◽  
Temporal Distribution ◽  
Sea Turtle ◽  
Absolute Temperature ◽  
Temperature Profiles ◽  
Sand Column ◽  
Sand Surface ◽  
Sand Temperature ◽  
Threshold Temperatures ◽  
Per Se

Sea turtle hatchlings typically emerge at night and temperature has often been suggested as controlling the timing of emergence. Models based on threshold temperatures, above which hatchling activity is inhibited, are not fully compatible with the observed temporal distribution of emergence. This study reports on the temporal pattern of hatchling emergence and associated sand temperature profiles and tidal regimes at Heron I., in the southern Great Barrier Reef, Australia. A new model is proposed on the basis of sand temperature gradients instead of the absolute temperature of the sand surface. The excellent fit between the temperature gradient model and the observed pattern of emergence suggests that it is the temperature gradient in the top 10cm of the sand column rather than an absolute temperature per se that turtle hatchlings use to time their emergence.

Use of pulse amplitude modulated (PAM) fluorometry for in situ measurements of photosynthesis in two Red Sea faviid corals

1998 ◽  
Vol 131 (4) ◽  
pp. 607-612 ◽  
Author(s):  
S. Beer ◽  
M. Ilan ◽  
A. Eshel ◽  
A. Weil ◽  
I. Brickner
Keyword(s):  
Red Sea ◽  
Pulse Amplitude ◽  
In Situ Measurements ◽  
Pam Fluorometry

Substrates with Programmable Heater Arrays for In-Situ Observation of Microstructural Evolution of Polycrystalline Films: Towards Real Time Control of Grain Growth

MRS Advances ◽  
2016 ◽  
Vol 1 (26) ◽  
pp. 1947-1952 ◽  
Author(s):  
Prabhu Balasubramanian ◽  
Chengjian Zheng ◽  
Yixuan Tan ◽  
Genevieve Kane ◽  
Antoinette Maniatty ◽  
...  
Keyword(s):  
Grain Growth ◽  
Microstructural Evolution ◽  
Control Strategies ◽  
Experimental Simulation ◽  
In Situ Observation ◽  
Temperature Profiles ◽  
Theory Approach ◽  
Polycrystalline Films ◽  
Real Time Control

ABSTRACTAn integrated experimental – simulation – control theory approach designed to enable adaptive control of microstructural evolution in polycrystalline metals is described. A micro-heater array, containing ten addressable channels, is used to create desired temperature profiles across thin polycrystalline films in situ to a scanning electron microscope (SEM). The goal is that on heating with controlled temperature profiles, the evolution of grain growth within the film can be continuously monitored and compared to Monte Carlo simulations of trajectories towards a desired microstructure. Feed-forward and feedback control strategies are then used to guide the microstructure along the desired trajectory.

Sentinel-2 mission Contribution for Supporting Bathymetric layers of SAFAGA coastal zone, Egypt

2021 ◽  
Author(s):  
Ramez Saeed ◽  
Saad Abdelrahman ◽  
Andrea Scozari ◽  
Abdelazim Negm
Keyword(s):  
Red Sea ◽  
Satellite Imagery ◽  
Data Science ◽  
New Technologies ◽  
Coefficient Of Determination ◽  
Change Environment ◽  
Bathymetric Data ◽  
Work Supports ◽  
Sentinel 2

<p><strong>ABSTRACT</strong></p><p>With the fast and highly growing demand for all possible ways of remote work as a result of COVID19 pandemic, new technologies using Satellite data were highly encouraged for multidisciplinary applications in different fields such as; agriculture, climate change, environment, coastal management, maritime, security and Blue Economy.</p><p>This work supports applying Satellite Derived Bathymetry (SDB) with the available low-cost multispectral satellite imagery applications, instruments and readily accessible data for different areas with only their benthic parameters, water characteristics and atmospheric conditions.  The main goal of this work is to derive bathymetric data needed for different hydrographic applications, such as: nautical charting, coastal engineering, water quality monitoring, sediment movement monitoring and supporting both green carbon and marine data science.  Also, this work proposes and assesses a SDB procedure that makes use of publicly-available multispectral satellite images (Sentinel2 MSI) and applies algorithms available in the SNAP software package for extracting bathymetry and supporting bathymetric layers against highly expensive traditional in-situ hydrographic surveys. The procedure was applied at SAFAGA harbor area, located south of Hurghada at (26°44′N, 33°56′E), on the Egyptian Red Sea coast.  SAFAGA controls important maritime traffic line in Red Sea such as (Safaga – Deba, Saudi Arabia) maritime cruises.  SAFAGA depths change between 6 m to 22m surrounded by many shoal batches and confined waters that largely affect maritime safety of navigation.  Therefore, there is always a high demand for updated nautical charts which this work supports.  The outcome of this work provides and fulfils those demands with bathymetric layers data for the approach channel and harbour usage bands electronic nautical chart of SAFAGA with reasonable accuracies.  The coefficient of determination (R<sup>2</sup>) differs between 0.42 to 0.71 after applying water column correction by Lyzenga algorithm and deriving bathymetric data depending on reflectance /radiance of optical imagery collected by sentinel2 missions with in-situ depth data values relationship by Stumpf equation.  The adopted approach proved to give  highly reasonable results that could be used in nautical charts compilation. Similar methodologies could be applied to inland water bodies.  This study is part of the MSc Thesis of the first author and is in the framework of a bilateral project between ASRT of Egypt and CNR of Italy which is still running.</p><p><strong>Keywords: Algorithm, Bathymetry, Sentinel 2, nautical charting, Safaga port, satellite imagery, water depth, Egypt.</strong></p>

scholarly journals Heat, health and hatchlings: associations of in situ nest temperatures with morphological and physiological characteristics of loggerhead sea turtle hatchlings from Florida

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Kelsey A Fleming ◽  
Justin R Perrault ◽  
Nicole I Stacy ◽  
Christina M Coppenrath ◽  
Alison M Gainsbury
Keyword(s):  
Life Stage ◽  
Sea Turtle ◽  
Additional Stress ◽  
Loggerhead Sea Turtle ◽  
Righting Response ◽  
In Situ Incubation ◽  
Risk Of Predation ◽  
Increased Risk ◽  
Incubation Temperatures

Abstract Incubation temperatures, in addition to an embryo’s genetic makeup, are critical in many aspects of adequate sea turtle embryonic development. The effects of high and low incubation temperatures on hatchling quality have been previously examined; however, many of these studies were conducted on relocated or laboratory-reared nests, which do not accurately reflect natural nest temperature fluctuations. To observe the impacts of varying in situ incubation temperatures on loggerhead sea turtle (Caretta caretta) hatchling morphology, various health variables and locomotor performance, temperature data loggers were deployed in 15 loggerhead nests on Juno Beach, Florida, between May and July 2018. Over the course of the study period, 10 morphological traits were measured, blood analytes and heart rate were assessed for the establishment of reference intervals and the self-righting response in seawater was evaluated. Warmer months were associated with smaller body size and higher body condition index, larger umbilical scar size, slower righting time, lower heart rates and higher packed cell volume, hemoglobin, total solids, total white blood cell count, absolute heterophils and absolute basophils. These findings provide evidence that higher in situ incubation temperatures have the potential to adversely affect hatchlings from warmer nests due to increased risk of predation from smaller body sizes, decreased physical responses and overall fitness, altered hemodynamic balance (e.g. dehydration) and potential inflammation and/or stress. With rising temperatures, we predict sea turtle hatchlings may have increasing risks of developing suboptimal physiological features affecting overall fitness and ultimately survival. These results demonstrate that rising environmental temperatures can negatively impact sea turtle hatchlings, thus representing additional stress on sea turtle populations and contributing to our understanding of potential pathophysiological effects of climate change on the delicate life-stage class of the sea turtle hatchling. This information will be useful for formulating effective future sea turtle management plans.

scholarly journals Phytoplankton Biomass and the Hydrodynamic Regime in NEOM, Red Sea

2021 ◽  
Vol 13 (11) ◽  
pp. 2082
Author(s):  
Nikolaos Papagiannopoulos ◽  
Dionysios Raitsos ◽  
Georgios Krokos ◽  
John Gittings ◽  
Robert Brewin ◽  
...  
Keyword(s):  
Red Sea ◽  
Late Summer ◽  
Marine Conservation ◽  
Conservation Strategy ◽  
Late Winter ◽  
Northwestern Part ◽  
Local Circulation ◽  
Chl A ◽  
Under Construction

NEOM (short for Neo-Mustaqbal) is a $500 billion coastal city megaproject, currently under construction in the northwestern part of the Red Sea, off the coast of Tabuk province in Saudi Arabia, and its success will rely on the preservation of biodiverse marine ecosystems. Monitoring the variability of ecological indicators, such as phytoplankton, in relation to regional environmental conditions, is the foundation for such a goal. We provide a detailed description of the phytoplankton seasonal cycle of surface waters surrounding NEOM using satellite-derived chlorophyll-a (Chl-a) observations, based on a regionally-tuned product of the European Space Agency’s Ocean Colour Climate Change Initiative, at 1 km resolution, from 1997 to 2018. The analysis is also supported with in situ cruise datasets and outputs of a state-of-the-art high-resolution hydrodynamic model. The open waters of NEOM follow the oligotrophic character of the Northern Red Sea (NRS), with a peak during late winter and a minimum during late summer. Coral reef-bound regions, such as Sindala and Sharma, are characterised by higher Chl-a concentrations that peak during late summer. Most of the open waters around NEOM are influenced by the general cyclonic circulation of the NRS and local circulation features, while shallow reef-bound regions are more isolated. Our analysis provides the first description of the phytoplankton seasonality and the oceanographic conditions in NEOM, which may support the development of a regional marine conservation strategy.

Estimating past and present sex ratios of sea turtles in Suriname

1996 ◽  
Vol 74 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Matthew H. Godfrey ◽  
N. Mrosovsky ◽  
R. Barreto
Keyword(s):  
Sea Turtles ◽  
Sex Ratios ◽  
Negative Relationship ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Dermochelys Coriacea ◽  
Green Turtles ◽  
Sand Temperature ◽  
Turtle Conservation ◽  
Sea Turtle Conservation

Leatherback (Dermochelys coriacea) and green (Chelonia mydas) sea turtles in Suriname lay eggs over several months of the year. During this nesting season, changes in rainfall produce changes in sand temperature, which in turn influence the sexual differentiation of incubating sea turtle embryos. The overall sex ratio of leatherback and green sea turtle hatchlings produced at Matapica beach in Suriname was investigated. Estimates of the sex ratios of these turtles in 1993 (green turtles 63.8% female, leatherbacks 69.4% female) were roughly 10% more female-biased than those from an earlier study in 1982. For both species, a significant negative relationship was found between monthly rainfall and monthly sex ratios. Using this relationship and data on rainfall in the past, it was possible to estimate overall sex ratios for an additional 12 years. These estimates varied considerably among different years, ranging from 20 to 90% female in the case of green turtles. Nevertheless, males tended to be produced primarily in April and May, while some females were produced in all months. Such seasonal patterns of production of turtles of different sexes have implications for sea turtle conservation programs that involve manipulating or harvesting eggs.

scholarly journals Quantifying meltwater refreezing along a transect of sites on the Greenland ice sheet

2015 ◽  
Vol 9 (2) ◽  
pp. 691-701 ◽  
Author(s):  
C. Cox ◽  
N. Humphrey ◽  
J. Harper
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
High Temporal Resolution ◽  
Temperature Profiles ◽  
Lateral Migration ◽  
Conservation Of Energy ◽  
Surface Mass ◽  
The Relationship ◽  
Heat Released

Abstract. On the Greenland ice sheet, a significant quantity of surface meltwater refreezes within the firn, creating uncertainty in surface mass balance estimates. This refreezing has the potential to buffer seasonal runoff to future increases in melting, but direct measurement of the process remains difficult. We present a method for quantifying refreezing at point locations using in situ firn temperature observations. A time series of sub-hourly firn temperature profiles were collected over the course of two melt seasons from 2007 to 2009 along a transect of 11 sites in the accumulation zone of Greenland. Seasonal changes in temperature profiles combined with heat flux estimates based on high-temporal-resolution temperature gradients enable us to isolate the heat released by refreezing using conservation of energy. Our method is verified from winter data when no refreezing takes place, and uncertainty is estimated using a Monte Carlo technique. While we limit our method to a subsection of firn between depths of 1 and 10 m, our refreezing estimates appear to differ significantly from model-based estimates. Furthermore, results indicate that a significant amount of refreezing takes place at depths greater than 1 m and that lateral migration of meltwater significantly complicates the relationship between total surface melt and total refreezing.

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