The Affect of Low Tide on the Digestion of Balanus glandula, the Acorn Barnacle.

The rocky intertidal zone, experiencing fully marine and fully terrestrial conditions, has become increasingly investigated as a model ecosystem for studying the future implications of climate change. The barnacle, Balanus glandula, a common rocky intertidal inhabitant, plays an important role as a key prey item for many organisms. Low tide can be particularly challenging for barnacles as they are marine organisms subjected to the abiotic conditions of a terrestrial environment. The most stressful of these are increased temperature and decreased oxygen availability. This study aimed to investigate how low tide impacts the energy budget, specifically the digestion, of B. glandula. Barnacles are unable to feed at low tide however, if they were able to digest at low tide, they could maximize their energy intake by emptying their stomach to prepare to feed at the next high tide. However, digestion is a metabolically costly activity, which could make it less energetically favorable to digest when there’s less oxygen available. To test for an effect of low tide on digestion, barnacles were fed, and the time to first fecal production measured as a ‘baseline’. This was repeated, but barnacles were exposed to either a 16ºC or 35 ºC low tide immediately after being fed. The change in digestion time was calculated by comparing these two times for each barnacle. It was found that regardless of temperature, barnacles delayed their digestion by about 50-60 minutes after exposure to a one hour low tide. To determine the energetic cost of digestion, the rate of oxygen consumption was compared between starved and digesting barnacles. I was unable to detect any evidence of elevated metabolic activity during digestion. Additional testing is needed to confirm these results as the barnacles may have not fed during the trial, thus had no food to digest. While it appears that increasing temperatures associated with climate change will have little impact on the digestion of barnacles at low tide, if climate change alters the duration of low tide, there could be an energetic impact to barnacles due to the slowing of their metabolism as indicated by the delay in their digestion

Measurements of Radio Pulse Reception with Stations of the ARA Experiment based on the SpiceCore Pulser Data Set

The Askaryan Radio Array Experiment located near the South Pole works to pinpoint specific instances of neutrinos from outside the solar system interacting with nucleons inside the Antarctic ice. Neutrinos are a subatomic particle that has nearly no mass and a net neutral charge. As they are, neutrinos tend not to interact with anything as they travel through space which means they can provide us with information about events occurring far from Earth that might not be easily attained through other methods. Neutrinos are known to be emitted from a myriad of sources, including the Sun, the interaction between cosmic rays and the Earth’s atmosphere, supernovae and as cosmic neutrino background believed to be a result of the Big Bang. As the neutrinos pass through and interact with the ice, their collisions with nucleons will emit energy in the form of radio waves. ARA detectors measure these radio waves to determine the neutrino flux: how many neutrinos pass through a given area over a given time. Specifically, the ARA experiment aims to measure ultra-high energy (UHE) neutrinos with energies above 10^15 electron volts. These UHE neutrinos are predicted to directly originate from cosmological sources. The measurement of this flux would be useful as evidence proving/disproving existing physics theories that expect certain flux values. If the measured flux deviates considerably from theorized values, it could also stand as an indication of physical phenomena that are not currently known. Due to the bending of radio waves propagating close to the surface of the ice, a phenomenon occurring due to the dependence of the index of refraction on depth, radio waves are not able to propagate from certain regions of space to the receiving ARA stations, according to classical linear optics. It has been observed at ARA, however, that the classical picture is violated in practice. Although a shadow zone does exist, it is smaller than what theory predicts. In this UCARE project, I worked on mapping the shadow zones found in the Antarctic ice experimentally, using calibration data generated by a radio transmitter inside a hole made for the SpiceCore project, which was recorded by the ARA stations

Enhanced Starting Track Real-time Stream for IceCube

IceCube real-time alerts allow for rapid follow-up observations of likely astrophysical neutrino events, enabling searches for multi-messenger counterparts. The Enhanced Starting Track Real-time Stream (ESTReS) is a real-time extension of the Enhanced Starting Track Event Selection (ESTES), a high astrophysical purity muon-neutrino sample recently used by IceCube to measure the astrophysical diffuse flux. A set of computationally cheap cuts allows us to run a fast filter in seconds. This online filter selects about 100 events per day to be sent to Madison, WI via satellite where the full ESTES event selection is applied within minutes. Events that pass the final set of cuts (ESTReS + ESTES) will be sent out as real-time alerts to the broader astrophysical community. ESTReS's unique contribution to the current real-time alerts will be events in the southern sky in the 5 TeV - 100 TeV range. We expect about 10.3 events per year which average 50% astrophysical purity. In this talk I will report the status of the ESTReS alert stream in the context of the IceCube real-time program.Comment: Presented at the 38th International Cosmic Ray Conference (ICRC2023). See arXiv:2307.13047 for all IceCube contribution

Interactions between microorganisms and marine microplastics: A call for research

Synthetic thermoplastics constitute the majority by percentage of anthropogenic debris entering the Earth’s oceans. Microplastics (≤5-mm fragments) are rapidly emerging pollutants in marine ecosystems that may transport potentially toxic chemicals into macrobial food webs. This commentary evaluates our knowledge concerning the interactions between marine organisms and microplastics and identifies the lack of microbial research into microplastic contamination as a significant knowledge gap. Microorganisms (bacteria, archaea, and picoeukaryotes) in coastal sediments represent a key category of life with reference to understanding and mitigating the potential adverse effects of microplastics due to their role as drivers of the global functioning of the marine biosphere and as putative mediators of the biodegradation of plastic-associated additives, contaminants, or even the plastics themselves. As such, research into the formation, structure, and activities of microplastic-associated microbial biofilms is essential in order to underpin management decisions aimed at safeguarding the ecological integrity of our seas and oceans

In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p

TXS 0506+056 with Updated IceCube Data

Past results from the IceCube Collaboration have suggested that the blazar TXS 0506+056 is a potential source of astrophysical neutrinos. However, in the years since there have been numerous updates to event processing and reconstruction, as well as improvements to the statistical methods used to search for astrophysical neutrino sources. These improvements in combination with additional years of data have resulted in the identification of NGC 1068 as a second neutrino source candidate. This talk will re-examine time-dependent neutrino emission from TXS 0506+056 using the most recent northern-sky data sample that was used in the analysis of NGC 1068. The results of using this updated data sample to obtain a significance and flux fit for the 2014 TXS 0506+056 "untriggered" neutrino flare are reported

Galactic Core-Collapse Supernovae at IceCube: “Fire Drill” Data Challenges and follow-up

The next Galactic core-collapse supernova (CCSN) presents a once-in-a-lifetime opportunity to make astrophysical measurements using neutrinos, gravitational waves, and electromagnetic radiation. CCSNe local to the Milky Way are extremely rare, so it is paramount that detectors are prepared to observe the signal when it arrives. The IceCube Neutrino Observatory, a gigaton water Cherenkov detector below the South Pole, is sensitive to the burst of neutrinos released by a Galactic CCSN at a level >10σ. This burst of neutrinos precedes optical emission by hours to days, enabling neutrinos to serve as an early warning for follow-up observation. IceCube\u27s detection capabilities make it a cornerstone of the global network of neutrino detectors monitoring for Galactic CCSNe, the SuperNova Early Warning System (SNEWS 2.0). In this contribution, we describe IceCube\u27s sensitivity to Galactic CCSNe and strategies for operational readiness, including "fire drill" data challenges. We also discuss coordination with SNEWS 2.0

All-Energy Search for Solar Atmospheric Neutrinos with IceCube

The interaction of cosmic rays with the solar atmosphere generates a secondary flux of mesons that decay into photons and neutrinos – the so-called solar atmospheric flux. Although the gamma-ray component of this flux has been observed in Fermi-LAT and HAWC Observatory data, the neutrino component remains undetected. The energy distribution of those neutrinos follows a soft spectrum that extends from the GeV to the multi-TeV range, making large Cherenkov neutrino telescopes a suitable for probing this flux. In this contribution, we will discuss current progress of a search for the solar neutrino flux by the IceCube Neutrino Observatory using all available data since 2011. Compared to the previous analysis which considered only high-energy muon neutrino tracks, we will additionally consider events produced by all flavors of neutrinos down to GeV-scale energies. These new events should improve our analysis sensitivity since the flux falls quickly with energy. Determining the magnitude of the neutrino flux is essential, since it is an irreducible background to indirect solar dark matter searches