Seal Hair Research Articles

Dynamics of mercury stable isotope compounds in Arctic seals: New insights from a controlled feeding trial on hooded seals Cystophora cristata

Accurate interpretation of mercury (Hg) isotopic data requires the consideration of several biotic factors such as age, diet, geographical range, and tissue metabolic turnover. A priori knowledge of prey-predator isotopic incorporation rates and Hg biomagnification is essential. This study aims to assess Hg stable isotopes incorporation in an Arctic species of Phocidae, the hooded seal Cystophora cristata, kept in human care for 24 months (2012–2014) and fed on a constant diet of Norwegian Spring Spawning herring Clupea harengus. We measured THg, MMHg and iHg levels, as well as Hg stable isotope composition with both mass dependent (MDF) and mass independent (MIF) fractionation (e.g. δ202Hg and Δ199,200,201,204Hg) in hooded seal kidney, liver, hair and muscle, in addition to herring muscle. We then calculated Hg MDF and MIF isotopic fractionation between hooded seals and their prey. We found a significant shift in δ202Hg between hooded seal hair (+0.80‰) and kidney (−0.78‰), and herring muscle. In hooded seals tissues δ202Hg correlated positively with MMHg percentage. These findings suggest that tissue-specific Hg speciation is the major driver of changes in Hg isotopic fractionation rates in this Arctic predator. Δ199Hg, Δ200Hg, Δ201Hg and Δ204Hg values did not vary between herring and hooded seal tissues, confirming their utility as tracers of Hg marine and atmospheric sources in top predators. To our knowledge, this represents the first attempt to assess complex Hg isotope dynamics in the internal system of Arctic Phocidae, controlling the effects of age, diet, and distribution. Our results confirm the validity of Hg stable isotopes as tracers of environmental Hg sources even in top predators, but emphasize the importance of animal age and tissue selection for inter-study and inter-species comparisons.

1500-year reconstruction of Circumpolar Deep Water intrusion and its impact on southern elephant seal populations in King George Island, West Antarctic Peninsula

Circumpolar Deep Water (CDW) intrusion onto the continental shelf significantly affects basal melting of ice shelves, oceanographic and ecological processes in the West Antarctic Peninsula (WAP). Understanding the changes in CDW upwelling and its impacts on marine ecology during historical periods is urgent. Here, we presented a new reconstruction for the variability in CDW intrusion onto the WAP over the past 1500 years by using the cadmium (Cd) concentrations in southern elephant seal hairs collected from King George Island. In addition, multi-proxies including the abundance of seal hairs and TOC, TN, LOI, and bio-elements in the sediments were integrated to infer historical seal populations by using the Generalized Additive Models (GAMs). The overall trend of Cd concentrations was well consistent with those of primary productivity and sea ice, reflecting the contribution of CDW on regional oceanic environment and ecology. Notably, during a period of ∼900–500 yr BP, enhanced CDW intrusion allowed for increased regional marine productivity and decreased sea ice, and ultimately promoting an increase in seal populations. Enhanced CDW intrusion was possibly driven by southward shift and intensification of the Southern Hemisphere westerly wind. These results indicated that large-scale atmospheric circulation patterns were coupled with regional oceanic circulation and ecological processes of the Southern Ocean.

Formulation and evaluation of herbal hair serum-a review

In the mammalian system the hair follicle is known to the most significant organ that determine, appearance, gender distinction, provides intense temperature protection and plays a role in self-defence. The younger generations have begun to suffer extreme hair loss problem due to many reasons. The hair loss is not temporary in most cases. but it results in alopecia. Many people suffering from hair loss is in search of multiple treatments due to extreme anxiety and tension. To improve hair growth and to prevent hair loss, hair root activation is required. Citrus sinensis is used to antidandruff protection hair care. It’s had antibacterial and anti-inflammatory properties. Nigella sativa improves the shine, strength, volume, and texture of hair. Flax seed is full of fatty acids and antioxidants that tend to remove pollutants and dead cells from the scalp. Coconut oil may help to moisturise and seal hair. They can help to prevent dry, flaky scalp and dandruff. This review article focuses on the materials required for the formulation of hair serum and various evaluation tests to evaluate hair serum.

CUT ABOVE THE REST: A MULTI‐DISCIPLINARY STUDY OF TWO SLATE KNIVES FROM FORAGER CONTEXTS IN COASTAL NORWAY

SummarySlate was a prominent tool material in the Scandinavian Stone Age. However, details of tool function have relied on morphology and have added little to our understanding of their role in hunting and processing. Here, we demonstrate that it is possible to identify both the use‐wear traces and residues from slate knives from northern Norway. By applying a multi‐disciplinary approach incorporating experimentation, use‐wear and organic residue analyses, we identified residues, including seal hair, and use‐traces which indicate the tools were used to process fresh marine mammals.

Whiskers provide time-series of toxic and essential trace elements, Se:Hg molar ratios, and stable isotope values of an apex Antarctic predator, the leopard seal

In an era of rapid environmental change and increasing human presence, researchers need efficient tools for tracking contaminants to monitor the health of Antarctic flora and fauna. Here, we examined the utility of leopard seal whiskers as a biomonitoring tool that reconstructs time-series of significant ecological and physiological biomarkers. Leopard seals (Hydrurga leptonyx) are a sentinel species in the Western Antarctic Peninsula due to their apex predator status and top-down effects on several Antarctic species. However, there are few data on their contaminant loads. We analyzed leopard seal whiskers (n = 18 individuals, n = 981 segments) collected during 2018–2019 field seasons to acquire longitudinal profiles of non-essential (Hg, Pb, and Cd) and essential (Se, Cu, and Zn) trace elements, stable isotope (ẟ15N and ẟ13C) values and to assess Hg risk with Se:Hg molar ratios. Whiskers provided between 46 and 286 cumulative days of growth with a mean ~ 125 days per whisker (n = 18). Adult whiskers showed variability in non-essential trace elements over time that could partly be explained by changes in diet. Whisker Hg levels were insufficient (<20 ppm) to consider most seals being at “high” risk for Hg toxicity. Nevertheless, maximum Hg concentrations observed in this study were greater than that of leopard seal hair measured two decades ago. However, variation in the Se:Hg molar ratios over time suggest that Se may detoxify Hg burden in leopard seals. Overall, we provide evidence that the analysis of leopard seal whiskers allows for the reconstruction of time-series ecological and physiological data and can be valuable for opportunistically monitoring the health of the leopard seal population and their Antarctic ecosystem during climate change.

Mercury offloaded in Northern elephant seal hair affects coastal seawater surrounding rookery

Methylmercury (MeHg) is a potent neurotoxin that is biomagnified approximately 1-10 million-fold in aquatic carnivores such as the Northern elephant seal (Mirounga angustirostris), whose excreta and molted pelage, in turn, constitute a source of environmental MeHg contamination at the base of marine food chains. The potential for this top-down contamination is greatest in coastal areas with productive marine ecosystems that provide ideal habitats for large marine mammal colonies that can number in the thousands. This recycling of MeHg was evidenced by comparing total mercury (HgT) and MeHg concentrations in seawater, and HgT in molted pelage of M. angustirostris, at the Año Nuevo State Reserve pinniped rookery with concentrations at neighboring coastal sites in Central California. Seawater MeHg concentrations around the rookery (average = 2.5 pM) were markedly higher than those at the comparison coastal sites (average = 0.30 pM), and were as high as 9.5 pM during the M. angustirostris molting season. As a consequence, excreta and molts from this marine mammal colony, and presumably other marine predator populations, constitute a major source of MeHg at the base of the local marine food chain.

Stable isotopes confirm a coastal diet for critically endangered Mediterranean monk seals

Understanding the ecology and behaviour of endangered species is essential for developing effective management and conservation strategies. We used stable isotope analysis to investigate the foraging behaviour of critically endangered Mediterranean monk seals (Monachus monachus) in Greece. We measured carbon and nitrogen isotope ratios (expressed as δ13C and δ15N values, respectively) derived from the hair of deceased adult and juvenile seals and the muscle of their known prey to quantify their diets. We tested the hypothesis that monk seals primarily foraged for prey that occupy coastal habitats in Greece. We compared isotope values from seal hair to their coastal and pelagic prey (after correcting all prey for isotopic discrimination) and used these isotopic data and a stable isotope mixing model to estimate the proportion of coastal and pelagic resources consumed by seals. As predicted, we found that seals had similar δ13C values as many coastal prey species and higher δ13C values than pelagic species; these results, in conjunction with mean dietary estimates (coastal=61 % vs. pelagic=39 %), suggest that seals have a diverse diet comprising prey from multiple trophic levels that primarily occupy the coast. Marine resource managers should consider using the results from this study to inform the future management of coastal habitats in Greece to protect Mediterranean monk seals.

Changes in trace elements during lactation in a marine top predator, the grey seal

Lactation in pinnipeds represents the most significant cost to mothers during the reproductive cycle. Dynamics of trace elements and their mobilization associated with energy reserves during such an intense physiological process remains poorly understood in marine mammals. The changes in tissue concentrations of 11 elements (Ca, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Se, V, and Zn) were investigated in a longitudinal study during the lactation period and during the post-weaning fast period. Blood, milk, blubber, and hair samples were collected sequentially from 21 mother–pup pairs of grey seals (Halichoerus grypus) from the Isle of May in Scotland. Maternal transfer through the milk was observed for all trace elements, except for Cd. As an indicator of the placental transfer, levels in pup lanugo (natal coat) revealed also the existence of maternal transfer and accumulation of all assayed trace elements during the foetal development. The placental and mammary barriers against non-essential metal transfer to offspring appear to be absent or weak in grey seals. Examining the contamination levels showed that this grey seal population seems more highly exposed to Pb than other phocid populations (2.2mg/kg dw of grey seal hair). In contrast, blood and hair levels reflected a lower Hg exposure in grey seals from the Isle of May than in harbour seals from the southeastern North Sea. This study also showed that trace element concentrations in blood and blubber could change rapidly over the lactation period. Such physiological processes must be considered carefully during biomonitoring of trace elements, and potential impacts that rapid fluctuations in concentrations can exert on seal health should be further investigated.

Effect of penguin and seal excrement on mercury distribution in sediments from the Ross Sea region, East Antarctica

Total mercury (Hg) concentration and several other geochemical parameters were determined for five sediment profiles from the Antarctic Ross Sea region. Our data exhibit significant positive correlations between Hg concentration and total organic carbon (TOC) content in all profiles, suggesting the predominant role of organic matter (OM) as a Hg carrier. The OM in the sediments originates primarily from penguin guano and algae. High Hg content in guano and a positive correlation between Hg and a guano bio-element (phosphorus, P) in the ornithogenic sediment profiles (MB6, BI and CC) indicate that Hg was strongly influenced by guano input. The bottom sediments of MB6 with seal hairs contain relatively high Hg. This increase is attributed to the input of seal excrement, suggesting that sedimentary Hg may be an effective trophic-level indicator from seals to penguins. The enrichment factor (EF) for Hg was calculated and the results indicated apparent Hg enrichment in the sediment profiles from the Ross Sea region caused by bio-vectors such as penguins and seals. Compared with typical sediments from other sites in Antarctica and the SQGs (sediment quality guidelines), the total amount of Hg in our study area is still not considered to be adversely high.

Relative Changes in Krill Abundance Inferred from Antarctic Fur Seal

Antarctic krill Euphausia superba is a predominant species in the Southern Ocean, it is very sensitive to climate change, and it supports large stocks of fishes, seabirds, seals and whales in Antarctic marine ecosystems. Modern krill stocks have been estimated directly by net hauls and acoustic surveys; the historical krill density especially the long-term one in the Southern Ocean, however, is unknown. Here we inferred the relative krill population changes along the West Antarctic Peninsula (WAP) over the 20th century from the trophic level change of Antarctic fur seal Arctocephalus gazella using stable carbon (δ13C) and nitrogen (δ15N) isotopes of archival seal hairs. Since Antarctic fur seals feed preferentially on krill, the variation of δ15N in seal hair indicates a change in the proportion of krill in the seal's diets and thus the krill availability in local seawater. For the past century, enriching fur seal δ15N values indicated decreasing krill availability. This is agreement with direct observation for the past ∼30 years and suggests that the recently documented decline in krill populations began in the early parts of the 20th century. This novel method makes it possible to infer past krill population changes from ancient tissues of krill predators.

Ecosystem evolution of seal colony and the influencing factors in the 20th century on Fildes Peninsula, West Antarctica

As the topmost predator in Antarctica, the seal is a unique indicator of Antarctic environment and climate changes. In this study, we collected a sediment core from the Fildes Peninsula of West Antarctica, and used cholesterol, cholestanol, epicoprostanol, coprostanol, and seal hair numbers as the proxy indicators of seal population size and phytol as of general vegetation, and we reconstructed the 20th century history of variation of the seal population and vegetation abundance on this island. The sealing industry in the early 20th century caused the dramatic decline of seal population, and the ban of seal hunting since the 1960s led to its recovery of seal population. The seal population during the past century was primarily controlled by human activities and krill density. The reconstructed relation between seal population and vegetation abundance may oifer new insights into Antarctic environment and ecology.

Variation of Antarctic seal population in response to human activities in 20th century

A sediment core was collected from the Fildes Peninsula of Antarctica, which contained numerous seal hairs and was identified to be seal excrement deposition. By analyzing its total organic carbon (TOC) and concentrations of bio-elements, the seal population changes of the past century were reconstructed. The variation of seal population in the last century on the Fildes Peninsula is primarily controlled by human activities. The sealing industry in the early 20th century caused the dramatic decline of seal population. The protection of the Antarctic seals since the 1960s and the reduced seal’s competition with whales for prey resources due to whaling lead to the recovery of seal population and make the high level of the seal population sustainable.

Arctic Clothing of North America: Alaska, Canada, Greenland by J.C.H. King, Birgit Pauksztat, and Robert Storrie

Arctic Clothing of North America: Alaska, Canada, Greenland by J.C.H. King, Birgit Pauksztat, and Robert Storrie

Mercury‐selenium association in antarctic seal hairs and animal excrements over the past 1,500 years

Strong positive correlations between selenium (Se) and total mercury (HgT) contents in the liver of marine mammals and mercury mine workers in modern times have been documented in numerous investigations. Herein, we report a positive correlation between Se and HgT concentrations over the past 1,500 years in the seal hairs and in the lake sediments amended by seal or penguin excrements on King George Island (63 degrees 23' S, 57 degrees 00' W), West Antarctica. Because the changes in the input of Se and Hg into the marine environments of the studied sites do not seem to be synchronous, this striking correlation indicates a self-protection mechanism in Antarctic seals and penguins: Every time there is heavier Hg burden, more Se is accumulated to reduce the toxicity of Hg. This positive correlation between Hg and Se contents in the seal hairs and excrement sediments, however, becomes insignificant in the recent 50 years for unknown reasons.

Identification of hairs found in leopard seal (Hydrurga leptonyx) scats

The leopard seal is a top-order predator in the Southern Ocean ecosystem and preys on a wide variety of vertebrate species including seals and penguins. We assessed the use of hairs found in leopard seal scats to identify the species of pinniped consumed. A reference collection of hairs was obtained from four potential leopard seal prey species including crabeater, Weddell, Ross, and Southern elephant seals. Discrimination techniques applied to terrestrial mammals did not allow for identification of the seal hairs. Instead, a 2-dimensional (2-D) and 6-dimensional (6-D) analysis technique utilising Mahalanobis distances (D2) was used. The smallest Mahalanobis distance together with the largest value of p(F) positively identified hairs from each species. The 6-D analysis was more accurate and applied to hairs found in the leopard seal scats. The majority of prey species were identified as crabeater seals, which are a known prey item of the leopard seal.

A 1500-year record of lead, copper, arsenic, cadmium, zinc level in Antarctic seal hairs and sediments

To reconstruct the profiles of heavy metal levels in the South Ocean ecosystem of Antarctica, the concentrations of lead (Pb), copper (Cu), arsenic (As), cadmium (Cd), and zinc (Zn) in seal hairs and lake sediments spanning the past 1500 years from Fildes Peninsula of King George Island and in weathering lake sediments from Nelson Island of West Antarctica were determined. The lead contents in the seal hairs and the weathering sediments show a sharp increase since the late 1800s, very likely due to anthropogenic contamination from modern industries. After the 1980s, the Pb content in seal hairs dropped by one-third, apparently due to the reduced usage of leaded gasoline in the Southern Hemisphere. Copper arises mainly from the weathering process, and its level may be substantially affected by climatic conditions. The concentrations of Cd, As, and Zn do not show any clear temporal trends.

HCl-soluble 87Sr/86Sr ratio in sediments impacted by penguin or seal excreta as a proxy for historical population size in the maritime Antarctic

The strontium (Sr) isotopic compositions in the HCl-soluble and insoluble fractions of sediments impacted by penguin and seal excreta in the maritime Antarctic were analyzed. The HCl-soluble phase of the sediments impacted by penguin guano has a high 87 Sr/ 86 Sr ratio (average 0.7087), close to the ratio in seawater (average 0.7092), suggesting that the 87 Sr/ 86 Sr ratios in the sediments are significantly impacted by penguin guano. The 87 Sr/ 86 Sr ratios in the HCl-soluble phase of the sediments impacted by seal excreta vary between 0.705066 and 0.706117, with an average of 0.705507, higher than those of the local bedrock, but lower than the ratio in modern seawater; they are interpreted to be a mixture of Sr from seal excreta (30 to 50 %) and the weathering products of the local bedrock (50 to 70 %). The Sr contributions from penguin guano and seal excreta were calculated using the 2-member isotope mixing equation, and they have a significant correlation with the historical penguin population size as estimated from other geochemical analyses and the seal hair density in the sediments, respectively. These results suggest that the 87 Sr/ 86 Sr ratios in the HCl-soluble fraction of sediments impacted by penguin or seal excreta can potentially be used as an indirect and new proxy for the historical population size of these sea animals in the maritime Antarctic.

A 2000-year record of mercury and ancient civilizations in seal hairs from King George Island, West Antarctica

The concentrations of total mercury (Hg T) and three bio-essential elements (phosphor, potassium, sodium) were analyzed in Antarctic seal hairs from a lake core spanning the past 2000 years and collected from King George Island (63°23′S, 57°00 ′W), West Antarctica. The Hg T concentration shows a significant fluctuation while the levels of the three bio-essential elements remain almost constant. The rise and fall of the Hg T concentration in the seal hairs are found to be closely coincided with ancient activities of gold and silver mining using Hg-amalgamation process around the world, especially in the Southern Hemisphere. Briefly, Hg T levels are high during five episodes of extensive gold and silver mining activities—Rome Empire and China Han Dynasty (∼18–300 A.D.), Maya period and China Tang (750–900 A.D.), Incas civilization and Christian Kingdom (1200–1500 A.D.), New world (1650–1800 A.D.), and modern industry period (1840 A.D.–present); they are low during four time periods of reduced gold and silver mining activities—the China Han and Rome fall (since 300 A.D.), Maya fall and Wartime period in China (1050–1250 A.D.), Pizarro coming (ca. 1532 A.D.) and Independence War of South America (1800–1830 A.D.). Two profiles of Hg T in other two lake cores, one affected by seal excrements and the other by penguin droppings, from the same region are similar to the one in seal hairs. The Hg concentration profile in the seal hairs is significantly correlated with the one in a peat bog of Southern Chile near King George Island. Since Hg is existent mainly at the form of methyl-mercury in seal hairs, this correlation supports a relationship and link between atmospheric mercury concentration and methyl-mercury production. Comparing with samples from American and European continents, the Antarctic seal hairs provide an archive of total mercury concentration in surface seawater of the South Ocean less affected by regional human activities, and this archive may provide a good reference for assessing the global Hg emissions, depositions and recycling in the past thousand years.

A preliminary study of elemental geochemistry and its potential application in Antarctic Seal palaeoecology

concentration (TN), organic carbon isotope (δ 13 C) and atomic C/N ratio shows that the organic matter in the sediments with many seal hairs has a marine origin, predominantly derived from seal excrements. Among the determined element/ oxide concentrations, S, Se, F, Zn, Hg, FeO and P 2O5 were found to be remarkably enriched in the sediments influenced by seal excrements with respect to the sediments with few or without seal hairs, and their concentrations displayed strong and positive correlations with organic matter abundance, indicating that they had the same source and transportation mechanism as the in situ organic material. A comparison of these element/oxide concentrations with the seal hair numbers showed that they had similar distribution patterns with depth, and the correlations were positive and statistically significant. Based upon these results, S, Se, F, Zn, Hg, FeO and P 2O5 in the seal excrement sediments were identified as potential bio-elements and their concentrations could potentially be used as inorganic geochemical indicators for tracking seal palaeoecological processes in the Antarctic region.

Paleoecological implications of the nitrogen isotope signatures in the sediments amended by Antarctic seal excrements

Abstract The nitrogen isotope signatures in the sediments amended by seal excrements, from Fildes Peninsula of King George Islands, Antarctica, were examined for their paleoecological application potential. The contents of total organic carbon (TOC) and total nitrogen (TN) and the atomic C/N ratios in the sediments show that the organic carbon and nitrogen are predominantly of marine origin and derived from seal excrements. The remarkably high δ15N values in the sediments may be related to at least two important factors of trophic enrichment and NH3 volatilization, which requires further studies. The large variations in the seal hair abundances and the determined δ15N values in the sediments signify similar changes of the historical seal populations around the study site. A significant negative correlation between the δ15N values and seal hair abundance was observed, and this suggests that the δ15N values, like the number of seal hairs, can be used as a paleoecological proxy for the historical seal popula...