Swimming through sand: using accelerometers to observe the cryptic, pre-emergence life-stage of sea turtle hatchlings.

Animals that hatch within a subterranean nest, such as turtle hatchlings, expend some of their limited energy reserves digging out through sand or soil to reach the surface. In sea turtles, this emergence process can take the hatchlings 3-7 days. However, we have a poor understanding of this process as it is difficult to observe what is occurring underground. Here, we utilize a novel method to characterize digging-out behaviour: affixing an accelerometer directly to newly hatched green turtles (Chelonia mydas) to record movement until nest emergence. Our data revealed that buried hatchlings maintained a head-up orientation but did not move in the expected left and right swaying motion associated with alternating limb crawling. Rather, they moved using dorsal-ventral heaving and pitching as if swimming vertically through the sand to the surface. Movement activity was irregular and brief, interspersed by many short periods of inactivity, mostly lasting less than 10 min. The first 24 h of head-up activity displayed no diel patterns, but the last 24 h prior to emergence involved more intense movement during night-time hours compared with daytime hours. Thus, our results add valuable new insight, and in some cases change previous assumptions, regarding the digging behaviours during the egg-to-emergence life stage in sea turtles.

Characterization of 25 new microsatellite markers for the green turtle (Chelonia mydas) and cross-species amplification in other marine turtle species.

BACKGROUND: The green sea turtle, Chelonia mydas, is a migratory species with a strong natal homing behavior leading to a complex population structure worldwide. The species has suffered severe declines in local populations; it is therefore crucial to understand its population dynamics and genetic structure to adopt appropriate management policies. Here, we describe the development of 25 new microsatellite markers specific to C. mydas and suitable for these analyses. METHODS AND RESULTS: They were tested on 107 specimens from French Polynesia. An average allelic diversity of 8 alleles per locus was reported and observed heterozygosity ranged from 0.187 to 0.860. Ten loci were significantly deviant from the Hardy-Weinberg equilibrium, and 16 loci showed a moderate to high level of linkage disequilibrium (4-22%). The overall Fis was positive (0.034, p-value < 0.001), and sibship analysis revealed 12 half- or full-sibling dyads, suggesting possible inbreeding in this population. Cross-amplification tests were performed on two other marine turtle species, Caretta caretta and Eretmochelys imbricata. All loci successfully amplified on these two species, though 1 to 5 loci were monomorphic. CONCLUSION: These new markers will not only be relevant for further analyses on the population structure of the green turtle and the two other species, but they will also be invaluable for parentage studies, for which a high number of polymorphic loci are necessary. This can provide important insight into male reproductive behavior and migration, an aspect of sea turtle biology that is of critical importance for the conservation of the species.

Characterisation of UDP-glucuronosyltransferase activity in sea turtle Chelonia mydas.

Uridine diphosphate glucuronosyltransferase (UGT) enzymes conjugate many lipophilic chemicals, such as drugs, environmental contaminants, and endogenous compounds, promoting their excretion. The complexity of UGT kinetics, and the location of enzyme active site in endoplasmic reticulum lumen, requires an accurate optimisation of enzyme assays.In the present study, we characterised UGT activity in liver microsomes of green turtles (Chelonia mydas), an endangered species. The conditions for measuring UGT activity were standardised through spectrofluorimetric methods, using the substrates 4-methylumbelliferone (4-MU) and uridine diphosphate glucuronic acid (UDPGA) at 30 °C and pH 7.4.The green turtles showed UGT activity at the saturating concentrations of substrates of 250 µM to 4-MU and 7 mM to UDPGA. The alamethicin, Brij®58, bovine serum albumin (BSA), and magnesium increased UGT activity. The assay using alamethicin (22 µg per mg of protein), magnesium (1 mM), and BSA (0.25%) reached the highest Vmax (1203 pmol·min-1mg·protein-1). Lithocholic acid and diclofenac inhibited UGT activity in green turtles.This study is the first report of UGT activity in the liver of green turtles and provides a base for future studies to understand the mechanisms of toxicity by exposure to contaminants in this charismatic species.

Fibropapillomatosis dynamics in green sea turtles Chelonia mydas over 15 years of monitoring in Akumal Bay, Quintana Roo, Mexico.

Fibropapillomatosis (FP) is a tumor disease that affects all sea turtle species but is mainly seen in green turtles Chelonia mydas. The pathology of FP has been described extensively, but its dynamics in populations over time have been less studied. We analyzed the dynamics of FP in a population of green turtles in Akumal Bay on the central coast of the Mexican Caribbean. A total of 475 green turtles were captured over 15 yr (2004-2018). The highest prevalence of FP was found in the largest turtles, and there was a positive relationship between FP prevalence and size of turtles. FP was first detected in 2008 at a prevalence of 1.6%, and annual prevalence increased markedly from 17.9% in 2015 to 54% by 2018. Likewise, severity of FP increased over time, with most turtles falling into moderately to severely diseased categories (tumor score 2). The average size of turtles with FP was significantly larger than the size of individuals without FP. Regression of tumors was seen in 21% of turtles, tumor score was higher in smaller individuals, and only tumor score 2 was present in the largest sea turtles. An increase in the prevalence and tumor score of FP coincided with the massive arrival of Sargassum in 2015, suggesting that altered environmental conditions may have played a role. The increased prevalence of FP in Akumal Bay prompts the need to explain what might be driving this phenomenon and how widespread it is in the Caribbean.

Illegal take of nesting sea turtles in Tortuguero, Costa Rica: Conservation, trade, or tradition?

Tortuguero, Costa Rica is considered the second largest green turtle (Chelonia mydas) rookery in the world. By 1950, Tortuguero was one of the sites with the greatest take of green turtles in the Caribbean. Currently, Tortuguero is a worldwide example for ecotourism-based on sea turtle conservation. However, illegal take of nesting turtles still occurs. We aimed to describe the illegal take at Tortuguero, estimating the minimum number of sea turtles taken using data collected during daily and weekly track surveys from 2005 to 2021. Additionally, we conducted 12 semi-structured interviews with key informants to obtain a better understanding of this activity. We documented 735 nesting turtles illegally taken at Tortuguero, being the green turtle the most affected species; these findings were also supported by our interviewees. Respondents stated that in Tortuguero the take of sea turtles has always occurred and traditions regarding sea turtle meat consumption are still present, even though it is considered shameful in the village. However, our interviewees affirmed that most of the sea turtles taken are traded to other locations away from Tortuguero. Our findings represent the minimum of illegal take (documented only at the beach), as not all the sea turtles taken were observed. Finally, despite long-standing conservation efforts carried out in Tortuguero, further changes in the National Park's management plans are needed, including more personnel and increased law enforcement. This may be necessary to reduce the impact on the Tortuguero green turtle nesting population in the near future.

Differences in Antibody Responses against Chelonid Alphaherpesvirus 5 (ChHV5) Suggest Differences in Virus Biology in ChHV5-Seropositive Green Turtles from Hawaii and ChHV5-Seropositive Green Turtles from Florida.

Fibropapillomatosis (FP) is a tumor disease associated with a herpesvirus (chelonid herpesvirus 5 [ChHV5]) that affects mainly green turtles globally. Understanding the epidemiology of FP has been hampered by a lack of robust serological assays to monitor exposure to ChHV5. This is due in part to an inability to efficiently culture the virus in vitro for neutralization assays. Here, we expressed two glycoproteins (FUS4 and FUS8) from ChHV5 using baculovirus. These proteins were immobilized on enzyme-linked immunosorbent assay plates in their native form and assayed for reactivity to two types of antibodies, full-length 7S IgY and 5.7S IgY, which has a truncated Fc region. Turtles from Florida were uniformly seropositive to ChHV5 regardless of tumor status. In contrast, in turtles from Hawaii, we detected strong antibody reactivity mainly in tumored animals, with a lower antibody response being seen in nontumored animals, including those from areas where FP is enzootic. Turtles from Hawaii actively shedding ChHV5 were more seropositive than nonshedders. In trying to account for differences in the serological responses to ChHV5 between green turtles from Hawaii and green turtles from Florida, we rejected the cross-reactivity of antibodies to other herpesviruses, differences in viral epitopes, or differences in procedure as likely explanations. Rather, behavioral or other differences between green turtles from Hawaii and green turtles from Florida might have led to the emergence of biologically different viral strains. While the strains from turtles in Florida apparently spread independently of tumors, the transmission of the Hawaiian subtype relies heavily on tumor formation.IMPORTANCE Fibropapillomatosis (FP) is a tumor disease associated with chelonid herpesvirus 5 (ChHV5) that is an important cause of mortality in threatened green turtles globally. FP is expanding in Florida and the Caribbean but declining in Hawaii. We show that Hawaiian turtles mount antibodies to ChHV5 mainly in response to tumors, which are the only sites of viral replication, whereas tumored and nontumored Floridian turtles are uniformly seropositive. Tumor viruses that depend on tumors for replication and spread are rare, with the only example being the retrovirus causing walleye dermal sarcoma in fish. The Hawaiian strain of ChHV5 may be the first DNA virus with such an unusual life history. Our findings, along with the fundamental differences in the life histories between Floridian turtles and Hawaiian turtles, may partly explain the differential dynamics of FP between the two regions.

Analysis of why sea turtles swim slowly: a metabolic and mechanical approach.

Animals with high resting metabolic rates and low drag coefficients typically have fast optimal swim speeds in order to minimise energy costs per unit travel distance. The cruising swim speeds of sea turtles (0.5-0.6 m s-1) are slower than those of seabirds and marine mammals (1-2 m s-1). This study measured the resting metabolic rates and drag coefficients of sea turtles to answer two questions: (1) do turtles swim at the optimal swim speed?; and (2) what factors control the optimal swim speed of turtles? The resting metabolic rates of 13 loggerhead and 12 green turtles were measured; then, the cruising swim speeds of 15 loggerhead and 9 green turtles were measured and their drag coefficients were estimated under natural conditions. The measured cruising swim speeds (0.27-0.50 m s-1) agreed with predicted optimal swim speeds (0.19-0.32 m s-1). The resting metabolic rates of turtles were approximately one-twentieth those of penguins, and the products of the drag coefficient and frontal area of turtles were 8.6 times higher than those of penguins. Therefore, our results suggest that both low resting metabolic rate and high drag coefficient of turtles determine their slow cruising speed.

DNA barcode analysis of the endangered green turtle (Chelonia mydas) in Mexico1.

Technological and analytical advances to study evolutionary biology, ecology, and conservation of green turtles (Chelonia mydas) are realized through molecular approaches including DNA barcoding. We characterized the usefulness of COI DNA barcodes in green turtles in Mexico to better understand genetic divergence and other genetic parameters of this species. We analyzed 63 sequences, including 25 from green turtle field specimens collected from the Gulf of Mexico and from the Mexican Pacific and 38 already present in the Barcode of Life Data Systems (BOLD). A total of 13 haplotypes were identified with four novel haplotypes from the Pacific Ocean and three novel haplotypes from the Atlantic Ocean. Intraspecific distance values among COI gene sequences by two different models were 0.01, demonstrating that there is not a subdivision for green turtle species. Otherwise, the interspecific distance interval ranged from 0.07 to 0.13, supporting a clear subdivision among all sea turtle species. Haplotype and total nucleotide diversity values of the COI gene reflect a medium genetic diversity average. Green turtles of the Mexican Pacific showed common haplotypes to some Australian and Chinese turtles, but different from the haplotypes of the Mexican Atlantic. COI analysis revealed new haplotypes and confirmed that DNA barcodes were useful for evaluation of the population diversity of green turtles in Mexico.

SPINAL ANESTHESIA IN GREEN SEA TURTLES (CHELONIA MYDAS) UNDERGOING SURGICAL REMOVAL OF CUTANEOUS FIBROPAPILLOMAS.

Techniques for anesthesia of green sea turtles (Chelonia mydas) are required for medical treatment. The use of spinal anesthesia has been reported in a few species of turtles for different purposes. The objective of this study was to evaluate the use of 2% lidocaine for spinal anesthesia of green sea turtles undergoing surgical removal of cutaneous fibropapillomas. Ten free-ranging green turtles presenting with cutaneous fibropapillomas were included in the study. Animals were accidentally captured or rescued by local fishermen and brought to the Ubatuba Research Base (Sao Paulo, Brazil) of the Brazilian Sea Turtle Conservation Program for rehabilitation. Animals were administered 2% lidocaine (0.2 ml/10 cm of carapace) in the epidural/subarachnoid space of the tail and monitored throughout surgery. The technique was effective for all animals, with fast onset of motor and sensory blockade (3 ± 1.76 min) and relatively fast recovery time (83.9 ± 16.2 min). Fibropapillomas were removed from all animals with no signs of pain (i.e., no behavioral response during surgical procedure, such as head and forelimb movement, showing discomfort) and they were all rehabilitated and successfully returned to their natural habitat. The technique was considered effective, safe, and affordable for use on green turtles undergoing surgical removal of cutaneous fibropapillomas.

COMPARISON OF AGAROSE GEL AND CAPILLARY ZONE ELECTROPHORESIS METHODS USING PLASMA FROM GREEN TURTLES (CHELONIA MYDAS).

Agarose gel electrophoresis (AGE) has been widely implemented throughout veterinary medicine and for analysis of plasma proteins of avian and reptile species. Capillary zone electrophoresis (CZE) is becoming a standard method in human clinical pathology laboratories but has not widely been used for the analysis of animal samples. The objective of the present study was to compare protein fractions derived from AGE and CZE methods using plasma from the green turtle (Chelonia mydas). Plasma samples were analyzed by AGE and CZE per manufacturer guidelines. The methods were assessed by CV analysis, Spearman's correlation, Passing-Bablok regression, and Bland Altman plots. CZE consistently resolved more fractions than AGE with three fractions observed in the prealbumin migrating region versus one for AGE and two fractions in the γ globulin region versus one for AGE. Compared with AGE, CZE showed a lower CV in intra-assay tests (1.0-4.9% vs 2.0-28.3%) and a lower or overlapping CV in interassay tests (1.0-10.6 vs 2.3-22.0). The prealbumin, α2 globulin, and ß globulin fractions correlated the least between the methods (for all three fractions: rs ≤ 0.28, P > 0.21). Moderate, significant correlations between AGE and CZE methods were observed for albumin (rs = 0.78, P < 0.0001) and γ globulins (rs = 0.78, P < 0.0001). CZE has a higher precision and ease of use over AGE and offers the opportunity to resolve additional protein fractions. This will necessitate the development of new conventions in placement of fraction delimits, definition of species-specific reference intervals, and evaluation of clinical utility in abnormal turtles.

Tumor re-growth, case outcome, and tumor scoring systems in rehabilitated green turtles with fibropapillomatosis.

Fibropapillomatosis (FP) is an infectious, neoplastic disease of major concern in sea turtle rehabilitation facilities. Rehabilitating sea turtles that undergo tumor removal surgery often have tumor regrowth and may experience mortality. We evaluated tumor score, removal, and regrowth in rehabilitating green sea turtles with FP in 4 rehabilitation facilities in the southeastern USA during 2009-2017. Of 756 cases, 312 (41%) underwent tumor removal surgery, 155 (50%) of those had tumor regrowth within an average of 46 ± 45 d, and 85 (27%) had multiple (>1) regrowth events. Of 756 turtles with FP, 563 (75%) did not survive after admission into a rehabilitation facility, including 283 (37%) that were euthanized and 280 that died without euthanasia (37%), and 193 survived, including 186 (25%) released and 7 (1%) placed in permanent captive care. Tumor removal surgery increased the odds of tumor regrowth but also enhanced survivorship, whereas tumor regrowth was not a significant predictor of case outcome. Three FP tumor scoring systems were used to assign tumor scores to 449 cases, and differing results emphasize that tumor scoring systems should be applied to the situations and/or location(s) for which they were intended. FP tumor score was not a significant predictor for the event or extent of FP tumor regrowth after surgical excision. Under current rehabilitation regimes, outcomes of rehabilitation for tumored turtles have a low probability of success. The results of this study may be used to help guide clinical decision-making and determine prognoses for rehabilitating sea turtles with FP.

COMPARISON OF HEMATOLOGICAL, PLASMA BIOCHEMICAL, AND NUTRITIONAL ANALYTES OF REHABILITATING AND APPARENTLY HEALTHY FREE-RANGING ATLANTIC GREEN TURTLES (CHELONIA MYDAS).

Green turtles (Chelonia mydas) are unique because hatchlings and pelagic juveniles are carnivorous, whereas later life stages become primarily herbivorous. Although this dietary shift is well understood, nutritional requirements at each developmental stage are not. Diet selection during rehabilitation is challenging, because turtles are often fed high-protein, low-fiber diets to counteract poor appetite and emaciation, which can result in gastrointestinal disorders. The objective of this study was to analyze hematology, plasma biochemistry, and nutritional analytes to determine the effect of diet on rehabilitating green turtle health and recovery. Turtles in rehabilitation at the Georgia Sea Turtle Center (GSTC) on Jekyll Island, Georgia (n = 21) were sampled at admission, mid-rehabilitation, and recovery. Duration of rehabilitation ranged from 48 to 233 days (mean = 117) and included a shift from a mixed seafood-vegetable diet at admission to a primarily herbivorous diet at recovery. For comparison, free-ranging turtles captured during an ongoing monitoring project in St. Lucie County, Florida (n = 34) were evaluated for the same variables. Several analytes improved during rehabilitation, including total protein, uric acid, potassium, and vitamins A and E. Others were significantly different, including higher cholesterol and triglycerides, but lower calcium, vitamin D, and magnesium in recovery compared with freeranging turtles. These variations illustrate the benefits of appropriate supportive care during rehabilitation as well as the importance of a species-specific diet for green turtles, and may facilitate formulation of nutritionally complete gel diets for this species under human care.

NEUROLOGIC AND COMPUTED TOMOGRAPHY FINDINGS IN SEA TURTLES WITH HISTORY OF TRAUMATIC INJURY.

Boat strikes have been widely documented as a major cause of anthropogenic trauma and mortality in sea turtles. Axial trauma in these species involves the head and/or carapace and may cause severe damage to the nervous and pulmonary systems. The aims of this study were to develop an updated protocol for neurologic examinations in sea turtles, to describe computed tomography (CT) findings in sea turtles with sustained trauma, and to associate CT findings with neurologic status in sea turtles with and without traumatic injury. Ten sea turtles were examined, six green (Chelonia mydas) and four loggerhead (Caretta caretta) turtles: seven underwent neurologic and CT examinations, two had CT examinations only, and one had a neurologic examination only. The updated neurologic examination protocol was considered useful in differentiating normal from abnormal neurologic status, however some of these tests remain unreliable in sea turtles. Sea turtles with no history of trauma were found to have normal carapace shape, vertebral column, and neurologic status. Sea turtles with history of traumatic injury (more than 10 years prior to examination) had findings dependent on trauma site. Those with head trauma had variable presentations dependent on location of injury; while those with carapace trauma had varying degrees of kyphosis, lordosis, and scoliosis of the carapace, vertebral fractures, and paraparesis. Kyphosis of the carapace was associated with vertebral fractures detected on CT; however, the severity of vertebral abnormalities was not associated with the severity of neurologic deficits. These findings suggest that a combination of neurologic and CT examination may be beneficial in determining clinical significance of carapace deformation and associated neurologic deficits in sea turtles with traumatic injury.

Individual specialization in a migratory grazer reflects long-term diet selectivity on a foraging ground: implications for isotope-based tracking.

Stable isotope analysis (SIA) can be a useful tool for tracking the long-distance movements of migratory taxa. However, local-scale sources of isotopic variation, such as differences in habitat use or foraging patterns, may complicate these efforts. Few studies have evaluated the implications of local-scale foraging specializations for broad-scale isotope-based tracking. Here, we use > 300 h of animal-borne video footage from green turtles (Chelonia mydas) paired with SIA of multiple tissues, as well as fine-scale Fastloc-GPS satellite tracking, to show that dietary specialization at a single foraging location (Shark Bay, Western Australia) drives a high level of among-individual δ13C variability (δ13C range = 13.2‰). Green turtles in Shark Bay were highly omnivorous and fed selectively, with individuals specializing on different mixtures of seagrasses, macroalgae and invertebrates. Furthermore, green turtle skin δ13C and δ15N dispersion within this feeding area (total isotopic niche area = 41.6) was comparable to that from a well-studied rookery at Tortuguero, Costa Rica, where isotopic dispersion (total isotopic niche area = 44.9) is known to result from large-scale (> 1500 km) differences in foraging site selection. Thus, we provide an important reminder that two different behavioral dynamics, operating at very different spatial scales, can produce similar levels of isotopic variability. We urge an added degree of caution when interpreting isotope data for migratory species with complex foraging strategies. For green turtles specifically, a greater appreciation of trophic complexity is needed to better understand functional roles, resilience to natural and anthropogenic disturbances, and to improve management strategies.

Synchronous activity lowers the energetic cost of nest escape for sea turtle hatchlings.

A potential advantage of group movement in animals is increased locomotion efficiency. This implies a reduced energetic cost for individuals that occur in larger groups such as herds, flocks and schools. When chelonian hatchlings hatch in the underground nest with finite energy for their post-hatching dispersal phase, they face the challenge of minimizing energetic expenditure while escaping the nest. The term 'social facilitation' has been used to describe the combined digging effort of sea turtle hatchlings during nest escape. Given that in a normal clutch, a substantial part of the energy reserve within the residual yolk is used by hatchlings in the digging out process, a decreased cohort size may reduce the energy reserve available to cross the beach and sustain the initial swimming frenzy. This hypothesis was experimentally tested by varying cohort size in hatchling green turtles (Chelonia mydas) and measuring energy expenditure during the nest escape process using open-flow respirometry. The energetic cost of escaping through 40 cm of sand was calculated to vary between 4.4 and 28.3 kJ per individual, the cost decreasing as the number of individuals in the cohort increased. This represents 11-68% of the energy contained in a hatchling's residual yolk at hatching. The reduced energetic cost associated with large cohorts resulted from both a lower metabolic rate per individual and a shortened nest escape time. We conclude that synchronous digging activity of many hatchlings during nest escape evolved not only to facilitate rapid nest emergence but also to reduce the energetic cost to individuals.

Conservation hotspots for marine turtle nesting in the United States based on coastal development.

Coastal areas provide nesting habitat for marine turtles that is critical for the persistence of their populations. However, many coastal areas are highly affected by coastal development, which affects the reproductive success of marine turtles. Knowing the extent to which nesting areas are exposed to these threats is essential to guide management initiatives. This information is particularly important for coastal areas with both high nesting density and dense human development, a combination that is common in the United States. We assessed the extent to which nesting areas of the loggerhead (Caretta caretta), the green (Chelonia mydas), the Kemp's ridley (Lepidochelys kempii), and leatherback turtles (Dermochelys coriacea) in the continental United States are exposed to coastal development and identified conservation hotspots that currently have high reproductive importance and either face high exposure to coastal development (needing intervention), or have low exposure to coastal development, and are good candidates for continued and future protection. Night-time light, housing, and population density were used as proxies for coastal development and human disturbance. About 81.6% of nesting areas were exposed to housing and human population, and 97.8% were exposed to light pollution. Further, most (>65%) of the very high- and high-density nesting areas for each species/subpopulation, except for the Kemp's ridley, were exposed to coastal development. Forty-nine nesting sites were selected as conservation hotspots; of those high-density nesting sites, 49% were sites with no/low exposure to coastal development and the other 51% were exposed to high-density coastal development. Conservation strategies need to account for ~66.8% of all marine turtle nesting areas being on private land and for nesting sites being exposed to large numbers of seasonal residents.

Metal contents of marine turtle eggs (Chelonia mydas; Lepidochelys olivacea) from the tropical eastern pacific and the implications for human health.

Concentrations of eight elements were measured in Chelonia mydas and Lepidochelys olivacea eggs collected along the Pacific coast of Panama. Manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and mercury (Hg) concentrations were similar to previous reports of these species from around the world, while lead (Pb) was lower than previous reports. Cd posed the highest health risk to people who regularly eat the eggs, with average consumption rates leading to target hazard quotients (THQ) of up to 0.35 ± 0.15. Our conclusions indicate that current turtle egg consumption in isolated, coastal Pacific communities may pose a health concern for young children, and that youth and young adults should limit their consumption of turtle eggs to reduce their total intake of nonessential metals.

Extreme temperatures, foundation species, and abrupt ecosystem change: an example from an iconic seagrass ecosystem.

Extreme climatic events can trigger abrupt and often lasting change in ecosystems via the reduction or elimination of foundation (i.e., habitat-forming) species. However, while the frequency/intensity of extreme events is predicted to increase under climate change, the impact of these events on many foundation species and the ecosystems they support remains poorly understood. Here, we use the iconic seagrass meadows of Shark Bay, Western Australia--a relatively pristine subtropical embayment whose dominant, canopy-forming seagrass, Amphibolis antarctica, is a temperate species growing near its low-latitude range limit--as a model system to investigate the impacts of extreme temperatures on ecosystems supported by thermally sensitive foundation species in a changing climate. Following an unprecedented marine heat wave in late summer 2010/11, A. antarctica experienced catastrophic (>90%) dieback in several regions of Shark Bay. Animal-borne video footage taken from the perspective of resident, seagrass-associated megafauna (sea turtles) revealed severe habitat degradation after the event compared with a decade earlier. This reduction in habitat quality corresponded with a decline in the health status of largely herbivorous green turtles (Chelonia mydas) in the 2 years following the heat wave, providing evidence of long-term, community-level impacts of the event. Based on these findings, and similar examples from diverse ecosystems, we argue that a generalized framework for assessing the vulnerability of ecosystems to abrupt change associated with the loss of foundation species is needed to accurately predict ecosystem trajectories in a changing climate. This includes seagrass meadows, which have received relatively little attention in this context. Novel research and monitoring methods, such as the analysis of habitat and environmental data from animal-borne video and data-logging systems, can make an important contribution to this framework.

Dynamics of Virus Shedding and In Situ Confirmation of Chelonid Herpesvirus 5 in Hawaiian Green Turtles With Fibropapillomatosis.

Cancers in humans and animals can be caused by viruses, but virus-induced tumors are considered to be poor sites for replication of intact virions (lytic replication). Fibropapillomatosis (FP) is a neoplastic disease associated with a herpesvirus, chelonid herpesvirus 5 (ChHV5), that affects green turtles globally. ChHV5 probably replicates in epidermal cells of tumors, because epidermal intranuclear inclusions (EIIs) contain herpesvirus-like particles. However, although EIIs are a sign of herpesvirus replication, they have not yet been firmly linked to ChHV5. Moreover, the dynamics of viral shedding in turtles are unknown, and there are no serological reagents to confirm actual presence of the specific ChHV5 virus in tissues. The investigators analyzed 381 FP tumors for the presence of EIIs and found that overall, about 35% of green turtles had lytic replication in skin tumors with 7% of tumors showing lytic replication. A few (11%) turtles accounted for more than 30% cases having lytic viral replication, and lytic replication was more likely in smaller tumors. To confirm that turtles were actively replicating ChHV5, a prerequisite for shedding, the investigators used antiserum raised against F-VP26, a predicted capsid protein of ChHV5 that localizes to the host cell nucleus during viral replication. This antiserum revealed F-VP26 in EIIs of tumors, thus confirming the presence of replicating ChHV5. In this light, it is proposed that unlike other virus-induced neoplastic diseases, FP is a disease that may depend on superspreaders, a few highly infectious individuals growing numerous small tumors permissive to viral production, for transmission of ChHV5.