Lunar Cycle Research Articles

Evidence of separate influence of moon and sun on light synchronization of mussel’s daily rhythm during the polar night

Marine organisms living at high latitudes are faced with a light climate that undergoes drastic annual changes, especially during the polar night (PN) when the sun remains below the horizon for months. This raises the question of a possible synchronization and entrainment of biological rhythms under the governance of light at very low intensities. We analyzed the rhythms of the mussel Mytilus sp. during PN. We show that (1) mussels expressed a rhythmic behavior during PN; (2) a monthly moonlight rhythm was expressed; (3) a daily rhythm was expressed and influenced by both sunlight and moonlight; and (4) depending on the different times of PN and moon cycle characteristics, we were able to discriminate whether the moon or the sun synchronize the daily rhythm. Our findings fuel the idea that the capability of moonlight to synchronize daily rhythms when sunlight is not sufficient would be a crucial advantage during PN.

Celestial risk factors in groin hernia repair and random statistical association: a nationwide register-based study.

We aimed to investigate how celestial phenomena like zodiac signs, lunar phases, and Friday the 13th impacted the risk of reoperation after groin hernia repair. We conducted a nationwide register-based study based on the Danish Hernia Database and Danish Patient Safety Authority's Online Register between 2000-2019. We included patients ≥18 years undergoing open Lichtenstein or laparoscopic groin hernia repair. The main outcomes were risk of reoperation after groin hernia repair in relation to patient and surgeon zodiac sign, lunar phase at the time of the repair, and Friday the 13th vs other Fridays. 151,901 groin hernias were included in the analysis of patient zodiac sign, and 25,075 groin hernias were included in the analysis of surgeon zodiac sign. Compared with the Sagittarius, there was a significantly higher risk of reoperation (HR [95% CI]) if the performing surgeon was born under the Capricorn (1.93 [1.16-3.12]); Pisces (1.68 [1.09-2.57]); Aries (1.61 [1.07-2.38]); Taurus (1.62 [1.04-2.54]); Cancer (2.21 [1.48-3.28]); or Virgo (1.71 [1.13-2.59]). Repairs performed under the waxing (1.23 [1.03-1.46]) and the new moon (1.54 [1.11-2.13]) had significantly higher risk of reoperation (HR [95% CI]) compared with the waning moon. Neither patient zodiac sign nor Friday the 13th affected risk of reoperation after groin hernia repair. Surgeons' zodiac sign and lunar phase significantly affected the risk of reoperation after groin hernia repair. Neither patients' zodiac sign nor Friday the 13th influenced on the risk of reoperation after groin hernia repair. This indicates why significant findings should be considered carefully to distinguish between random statistical association and cause-and-effect relations.

Biologically meaningful moonlight measures and their application in ecological research

Light availability is one of the key drivers of animal activity, and moonlight is the brightest source of natural light at night. Moon phase is commonly used but, while convenient, it can be a poor proxy for lunar illumination on the ground. While the moon phase remains effectively constant within a night, actual moonlight intensity is affected by multiple factors such as disc brightness, position of the moon, distance to the moon, angle of incidence, and cloud cover. A moonlight illumination model is presented for any given time and location, which is significantly better at predicting lunar illumination than moon phase. The model explains up to 92.2% of the variation in illumination levels with a residual standard error of 1.4%, compared to 60% explained by moon phase with a residual standard error of 22.6%. Importantly, the model not only predicts changes in mean illumination between nights but also within each night, providing greater temporal resolution of illumination estimates. An R package moonlit facilitating moonlight illumination modelling is also presented. Using a case study, it is shown that modelled moonlight intensity can be a better predictor of animal activity than moon phase. More importantly, complex patterns of activity are shown where animals focus their activity around certain illumination levels. This relationship could not be identified using moon phase alone. The model can be universally applied to a wide range of ecological and behavioural research, including existing datasets, allowing a better understanding of lunar illumination as an ecological resource.Significance statementMoon phase is often used to represent lunar illumination as an environmental niche, but it is a poor proxy for actual moonlight intensity on the ground. A model is therefore proposed to estimate lunar illumination for any given place and time. The model is shown to provide a significantly better prediction of empirically measured lunar illumination than moon phase. Importantly, it also has much higher temporal resolutions, allowing to not only detect selectiveness for light levels between nights but also within each night, which is not achievable with moon phase alone. This offers unprecedented opportunities to study complex activity patterns of nocturnal species using any time-stamped data (GPS trackers, camera traps, song meters, etc.). It can also be applied to historical datasets, as well as facilitate future research planning in a wide range of ecological and behavioural studies.

Vertical distribution patterns of zooplankton across a gradient of fish predation in boreal lakes

Abstract Different physical factors such as solar radiation and wind impose strong vertical gradients in lake water columns and have important consequences on the distribution of aquatic organisms, from bacteria to fish. The heterogeneous vertical distribution of zooplankton in lakes is a clear example of a pattern related to these vertical gradients. Although the vertical distribution of zooplankton is probably controlled by multiple factors including light, resources, and predation, we still lack an integrated view of the interplay among these potential drivers, which are most often analysed separately. Moreover, most studies focussed on temperate lakes in which both phytoplankton resources and predation risk from fish are highest in the epilimnion, whereas only a few investigated boreal lakes, where phytoplankton is often more abundant in the metalimnion than in the epilimnion and cold‐stenothermic fishes prey on zooplankton below the warm epilimnetic layers. Here we investigated zooplankton vertical distribution in the epi‐ and metalimnetic waters of 17 boreal lakes that varied in fish predation, resource quantity and quality, and optical properties. The lakes were sampled at midday and midnight at five different depths in the well‐lit epi‐ and metalimnetic layers, where the strongest gradient in light (and predation risk) were expected. We used a multi‐model inference approach combined with linear modelling to examine the relative effects of physical factors (light attenuation, temperature and moon phase), resources (chlorophyll‐a and polyunsaturated fatty acids), and predation (fish and Chaoborus) on depth selection in four zooplankton taxa. All taxa showed a heterogeneous vertical distribution that in most cases had a clear diel migration pattern. Both predation and resources (food and temperature gradient) were associated with vertical depth selection by zooplankton, but each taxon had different responses to each factor. Vertebrate predators were associated with the vertical distribution of Daphnia, Calanoida, and Cyclopoida, but—unexpectedly—all these taxa reduced their diel vertical migration patterns in the presence of fish. Invertebrate predators were better correlated with the distribution of Cyclopoida, which tended to be shallower when Chaoborus was abundant. Food abundance seemed important for Holopedium glacialis and Calanodia, while the temperature gradient was partly associated with both Daphnia spp. and Calanoida distribution. Finally, we found an intriguing, albeit weak, positive association between the vertical distribution of Cyclopoida and that of food quality. These results showed that taxa less vulnerable to predators such as H. glacialis perform inverse DVM, and that this is at least partly related to moon phase rather than to fish predation. They also suggest that boreal lakes colonised by stenothermic planktivorous fish behave differently from the classical DVM paradigm, given that visual predators do not have access to fully lit layers.

Observation of Scintillation Enhancements and Large‐Scale Structures Within the Equatorial Ionization Anomaly During a Sudden Stratospheric Warming Event

AbstractTotal electron content (TEC) and L‐band scintillations measured by several networks of GPS and GNSS receivers that operate in South and Central America and the Caribbean region are used to observe the morphology of the equatorial ionization anomaly (EIA), examine the evolution of plasma bubbles, and investigate the enhancement of L‐band scintillations that occurred on February 12 and 13, 2016. A few weak and short magnetic storms developed these days, and a minor sudden stratospheric warming (SSW) event was initiated a few days before. During these unusual conditions, TEC maps reported a split of the otherwise continuous crests of the EIA and the formation of a large‐scale (thousands of kilometers) almost‐circular structure. The western part of the southern crest faded, and a north‐south aligned segment developed near the center of the South American continent, joining the north and south crests of the EIA, forming an anomaly that resembled a closed loop on the eastern side of the continent. Concurrently with the anomaly events, several GPS stations reported increases in the L‐band scintillation index from 0.4 to values greater than 1. We analyzed TEC values from receivers between ±6° from the magnetic equator to identify and follow TEC depletions associated with plasma bubbles when they reach different stations. Although the magnetic activity was moderate (Kp = 3°), we believe that the anomaly redistribution and the scintillation enhancements are not related to a prompt penetration electric field but to enhancing the semidiurnal lunar tide propitiated by the onset of the minor SSW event. We found that depending on the lunar tide phase cycle, the neutral wind's meridional component can augment sub‐km scale irregularities and enhance L‐band scintillations through the wind gradient instability when U·n < 0 or the action of wind gradients (U) within the bubbles. Our observations imply that the SSW event enables prominent changes in the thermosphere wind system at F‐region altitudes.

Four Elegies

Four Elegies

Estimation of Ground-Level PM2.5 Concentration at Night in Beijing-Tianjin-Hebei Region with NPP/VIIRS Day/Night Band

Reliable measures of nighttime atmospheric fine particulate matter (PM2.5) concentrations are essential for monitoring their continuous diurnal variation. Here, we proposed a night PM2.5 concentration estimation (NightPMES) model based on the random forest model. This model integrates the radiance of the Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB), moon phase angle, and meteorological data. We collected 13486 samples from the Beijing Tianjin–Hebei (BTH) region. The determination coefficient (R2) of the NightPMES model was 0.82, the root mean square error (RMSE) was 16.67 µg/m3, and the mean absolute error (MAE) was 10.20 µg/m3. The applicability analysis of the moon phase angles indicated that the amount of data available increased by 60% while the accuracy remained relatively unchanged. In the seasonal model, the meteorological factors and DNB radiance were found to be the primary factors affecting the PM2.5 concentration in different seasons. In conclusion, this study provided a method for estimating nighttime PM2.5 concentration that will improve our understanding of air pollution and associated trends in PM2.5 variation.

Four decades of phenology in an alpine amphibian: trends, stasis, and climatic drivers

Strong phenological shifts in response to changes in climatic conditions have been reported for many species, including amphibians, which are expected to breed earlier. Phenological shifts in breeding are observed in a wide number of amphibian populations, but less is known about populations living at high elevations, which are predicted to be more sensitive to climate change than lowland populations. The goal of this study is to assess the main factors determining the timing of breeding in an alpine population of the common toad (Bufo bufo) and to describe the observed shifts in its breeding phenology. We modelled the effect of environmental variables on the start and peak dates of the breeding season using 39 years of individual-based data. In addition, we investigated the effect of the lunar cycle, as well as the individual variation in breeding phenology. Finally, to assess the individual heterogeneity in the timing of breeding, we calculated the repeatability of the timing of arrival at the breeding site. Breeding advanced to earlier dates in the first years of the study but the trend continued only until the mid 1990s, and stabilised afterwards. Overall, toads are now breeding on average around 30 days earlier than at the start of the study period. High temperatures and low snow cover in winter and spring, as well as reduced spring precipitation were all associated with earlier breeding. Additionally, we found evidence of males arriving on average before females at the breeding site but no clear and strong effect of the lunar cycle. We only found weak evidence of among-individual variation in shifts in the breeding phenology, as well as a low repeatability of arrival timing. Our findings show that the observed changes in breeding phenology are strongly associated with the environmental conditions. These results contribute to filling a knowledge gap on the effects of climate change on alpine amphibian populations. Moreover, we show that changes in phenology, especially in the mountains, can be hard to predict as local microclimatic conditions do not necessarily reflect the observed global climatic trends.

Postmortem submersion intervals in the River Thames

This paper catalogues a dataset drawn from Metropolitan Police records in the period 2004-2015 regarding drowning victims recovered from a tidal stretch of the River Thames and provides a comparative study with a similar dataset from the time period 1956-1959 by the County of London (Western District), H.M. Coroner of that time, Gavin Thurston, from the information gathered in his professional role. In addition to drawing comparisons between these time periods the paper draws inferences regarding the Post-Mortem Submersion Interval (PMSI) and proposing further study required. Both datasets show a significant bias towards male subjects counter to other comparable data in the literature. This bias is even more pronounced in the 2004-2015 period where additionally there are significantly more incidents during Full Moon Lunar Phase. Some weak seasonal trends were observed regarding equinoctial peaks but these were not statistically significant. There are few clear trends observable in factors that might influence Post-Mortem Submersion Interval although there was a weak and counter-intuitive inverse relationship between clothing weight and time in water. KEY WORDS: PMSI, Drowning, GIS

Home ranges, directionality and the influence of moon phases on the movement ecology of Indian flying fox males in southern India.

Flying foxes of the genus Pteropus are amongst the largest fruit bats and potential long-range pollinators and seed dispersers in the paleotropics. Pteropus giganteus (currently P. medius) is the only flying fox that is distributed throughout the Indian mainland, including in urban and rural areas. Using GPS telemetry, we mapped the home ranges and examined flight patterns in P. giganteus males across moon phases in a semi-urban landscape in southern India. Home range differed between the tracked males (n=4), likely due to differences in their experience in the landscape. We found that nightly time spent outside the roost, distance commuted and the number of sites visited by tracked individuals did not differ significantly between moon phases. In 61% of total tracked nights across bats, the first foraging site was within 45˚ of the emergence direction. At the colony-level, scan-based observations showed emergence flights were mostly in the northeast (27%), west (22%) and southwest (19%) directions that could potentially be related to the distribution of foraging resources. The movement ecology of fruit bats in relation to the pollination and seed dispersal services they provide requires to be investigated in future studies. This article has an associated First Person interview with the first author of the paper.

First person – Baheerathan Murugavel

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping researchers promote themselves alongside their papers. Baheerathan Murugavel is first author on ‘ Home ranges, directionality and the influence of moon phases on the movement ecology of Indian flying fox males in southern India’, published in BiO. Baheerathan is a PhD Student in the lab of Professor Hema Somanathan at School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, India, investigating the behaviour, sensory, and movement ecology of bats.

A Markov Chain Monte Carlo (MCMC) Multivariate Analysis of the Association of Vital Parameter Variation With the Lunar Cycle in Patients Hospitalized With COVID-19.

Over the last three years, the world has been battling a long-drawn pandemic resulting from the coronavirus outbreak. Despite the safety measures, there have been multiple pandemic waves happening throughout the world. Therefore, it is necessary to understand the fundamental characteristics of COVID-19 transmission and pathogenesis to overcome the threat of the pandemic. This study focused on hospitalized COVID-19 patients because of their high mortality rate, which indicates the need to improve inpatient management. Based on the cyclic nature of the pandemic, observations were made to examine the influence of lunar phases on six vital parameters of COVID-19 patients. A multivariate analysis was carried out to study the interactions of lunar phase pairwise on COVID-19 statuses and COVID-19 status pairwise on lunar phases by treating six vital parameters as independent entities. The results of multivariate analysis on the data of 215,220 vital values showed that lunar phases are associated with trends in variations in the vital parameters of COVID-19-infected patients. In summary, our results show that patients infected with COVID-19 appear to be more susceptible to lunar influence compared to non-COVID-19 patients. Furthermore, this study shows a vital parameter destabilization window (DSW) that can help identify which hospitalized COVID-19 patients can recover. Our pilot study forms the basis for future studies to eventually establish the incorporation of variation of vital signs with the lunar cycle into the standard of care for COVID-19 patients.

Fish Use of a Borland-Type Fish Lock in an Iberian River

Fish locks were fitted at dams to improve fish migration in Europe, but also in America and Australia. In Iberia, several dams were equipped with locks in the 1970s and 1980s, and in this study the fish use of the Borland fish lock installed in the most downstream dam in the Douro River was investigated by visualizing fish during each cycle. Moreover, a creel survey was conducted encompassing the same period to characterize the fish caught downstream. During the study, 770 lock cycles were completed, with 58,982 fish being observed in 234 cycles, mostly moving upstream. Eels (Anguilla anguilla) were the most numerous, being followed by the mugilids (Chelon ramada and Mugil cephalus). The number of fish using the lock was low from November to April, increasing from May to July, and was related to tide height, discharge at the powerplant tailrace, moon phase and time of day. Sea lamprey (Petromyzon marinus) and shads (Alosa spp.) were caught downstream of the dam but were never found using the lock. While more research is needed to assess the fate of the eels moving upstream, management of the anadromous taxa in the Douro River must rely on the last 20 km of the river.

Mapping the astronomy content knowledge of Chilean in-service teachers

ABSTRACT This paper reports a mapping of the astronomy content knowledge held by a sample of 171 Chilean in-service teachers, both from primary and secondary education, using a multiple-choice test. The responses were analysed by total achievement, and the proportion of alternative conceptions for each item was identified. Moreover, the test items were divided by Big Ideas in Astronomy and curricular topics to analyse teachers’ performance by subject, and the effect of some demographic factors was calculated. The results show a relatively low level of astronomy content knowledge and a considerable presence of alternative conceptions amongst Chilean in-service teachers, especially in day-to-day topics like diurnal motion, seasons, and Moon phases. Furthermore, we detected a significant effect on secondary teachers’ performance depending on their teaching degree and on primary teachers’ performance concerning their gender and previous participation in astronomy professional development programmes. Our outcomes offer evidence to improve astronomy teacher training, especially in the Chilean context, and contribute to the still scarce astronomy education research from the country.

Minimising discards while taking revenue into account: Spatio-temporal assessment of catches in an artisanal shrimp trawl fishery in Peru

Around 4.2 million tonnes of fish and other species, some of which are of conservation concern, are discarded every year in bottom trawl fisheries. This study focusses on a small-scale shrimp trawl fishery located in northern Peru that operates with high level of discards which causes conflict with other local fishers. Despite trawling being an illegal activity within the 5NM off the coast, this fishery has been operating in these inshore areas for over 40 years because it sustains the well-being of hundreds of fishers. This study aimed to identify the factors that affect the spatio-temporal variation in catches in order to propose recommendations that can be adopted by fishers to minimise their impact on the ecosystem while still providing economic opportunities. The spatial distributions of shrimp, main commercial species and discards were modelled over time using hierarchical generalised additive models. Strong spatio-temporal variation was observed for all catch components and moon phase affected commercial species and discards differently. The results show that, to reduce the environmental impacts of this fishery in the short-term, the fishing area could be divided into north and south and that fishing activities should be limited to the southern area in the autumn. Other recommendations rely on temporal closures during the week of the first quarter of the moon phase. Finally, considering the institutional weaknesses in monitoring, control and surveillance, we suggest that the only realistic approach to reduce the fishery's environmental impacts in the short-term is to foster the willingness of fishers to adopt responsible fishing practices. Yet, long-term solutions will require comprehensive co-management efforts.

The Role of Microteaching on Pre-Service Primary School Science Teachers’ Conceptual Understandings Regarding Phases of the Moon

Microteaching is a significant way to prepare pre-service teachers to overcome specific challenges in a natural classroom environment. It is widely accepted that pre-service science teachers gain pedagogical benefits from microteaching activities. Furthermore, microteaching enhances the conceptual understanding of the presenter on the related teaching topics. This research intends to map two pre-service science teachers’ conceptual understanding before and after engaging in microteaching on the concept of phases of the moon. The data were collected through pre and post-interviews and observations of microteaching. Activated knowledge elements during interviews and microteaching were determined and compared. The study’s results provided evidence that microteaching is a fruitful way to improve pre-service science teachers' understanding of phases of the moon. Furthermore, it was detected that both the quality and quantity of pre-service science teachers' knowledge elements increased after their microteaching engagements

Reproductive condition of the black-lip pearl oyster Pinctada margaritifera during the lunar phase.

This study analyzed the relationship between the lunar phase and the reproductive cycle of Pinctada margaritifera inhabiting Weno Island, Chuuk Lagoon, Micronesia. We measured indicators of maturity (gonadosomatic index [GSI]and sexual maturation-related genes) and investigated changes in the gonadal maturity stages (GMS) of P. margaritifera over lunar cycle. GSI was higher around the full moon. GMS of P. margaritifera were classified as the early gametogenesis stage, ripe and spawning stage, and spent and degenerating stage. A large percentage of oysters was observed in the ripe and spawning stage at the first quarter moon in female and the full moon in male as well as in the spent and degenerating stages at the third quarter moon in both sexes. In addition, the expression of doublesex- and mab-3-related transcription factor 2 (DMRT2) in the male P. margaritifera black-lip pearl oyster was the highest during the full and third quarter moon phases, whereas no difference in expression was observed with the lunar phase in females. In contrast, the expression of vitellogenin (VTG) was the highest in female P. margaritifera during the first and third quarters. No difference in expression was observed according to the lunar phase in males. The results suggest that the lunar phase directly affects the expression of sexually mature gonads in P. margaritifera black-lip pearl oyster.

Hidden Cycles of Time in the Layout of Mesoamerican Ballcourts

ABSTRACT Thousands of ballcourts are known throughout Mesoamerica, as they are usually a main component of public architecture at mostly high-ranking archaeological sites. These buildings appear in different designs and layouts and were deeply tied to politics, religion, sacred belief, ritual, ceremonies, and sport. Considering that the construction of public buildings followed well-established architectural standards in accordance with social norms and religious concepts, I hypothesize that ballcourts were designed using closed polygon layouts with lengths and areas that displayed significant worldview numbers and time counts. Analysis of the layouts of 28 ballcourts from 17 archaeological sites indicates that Mesoamericans intentionally plotted short- and long-term annual and ritual calendric counts, and lunar and Venus synodic cycles. It is concluded that these buildings hosted public events to commemorate the completion or beginning of a new time cycle and to honor the related deities for whom they were built.

Don’t Blame It on the Moon

Aim: There is a longstanding, popular belief that the lunar cycle has an impact on human behavior. The purpose of this study was to evaluate changes in behavior amongst psychiatric patients at a mental health facility over a 7-year period in comparison to the lunar cycle. Method: A retrospective analysis was conducted using behavioral occurrence reports from a hospital database for a 252-bed adult psychiatric hospital in Canada. There were 7,153 behavioral occurrences during the study period across 627,763 patient days. Results: Occurrences varied greatly by lunar day, with peaks above the average for some days and dips below for others, while maintaining the average for the rest of the lunar days; however, no specific pattern was observed and the variation was not statistically significant. The popular notion that a full moon arouses behavioral disturbances was not supported in this analysis of psychiatric inpatients. Clinical Implications: The belief that the full moon causes escalating behaviors should be critically evaluated by healthcare providers as it may contribute to further stigmatization of individuals with mental illness.

Sex-based divergence in tidal, lunar and seasonal cycles of activity in the olive sea snake, Aipysurus laevis (Elapidae, Hydrophiinae)

Sex-based divergence in tidal, lunar and seasonal cycles of activity in the olive sea snake, Aipysurus laevis (Elapidae, Hydrophiinae)