Publications by authors named "Mark C Benfield"

This study examines trends in PPE (masks, gloves) and disinfecting wipes over three years of the pandemic. The densities of discarded masks, wet wipes, and gloves (personal protective equipment: PPE), were quantified on the streets of Canakkale, Turkey during similar time periods in 2020, 2021 and 2022. Geotagged images of PPE on the streets and sidewalks were documented with a smartphone, while the track of an observer was recorded using a fitness tracker app along a 7.

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Recent research has revealed that shrimp sensory quality may be affected by ocean acidification but we do not exactly know why. Here we conducted controlled pH exposure experiments on adult tiger shrimp, which were kept in 1000-L tanks continuously supplied with coastal seawater. We compared survival rate, carapace properties and flesh sensory properties and amino acid composition of shrimp exposed to pH 7.

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The Deepwater Horizon spill is one of the largest environmental disasters with extensive impacts on the economic and ecological health of the Gulf of Mexico. Surface oil and coastal impacts received considerable attention, but the far larger oil spill in the deep ocean and its effects received considerably less examination. Based on 2017 ROV surveys within 500 m of the wellhead, we provide evidence of continued impacts on diversity, abundance and health of deep-sea megafauna.

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Despite the rapid increase in the number and applications of plankton imaging systems in marine science, processing large numbers of images remains a major challenge due to large variations in image content and quality in different marine environments. We constructed an automatic plankton image recognition and enumeration system using an enhanced Convolutional Neural Network (CNN) and examined the performance of different network structures on automatic plankton image classification. The procedure started with an adaptive thresholding approach to extract Region of Interest (ROIs) from in situ plankton images, followed by a procedure to suppress the background noise and enhance target features for each extracted ROI.

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For thousands of years humankind has sought to explore our oceans. Evidence of this early intrigue dates back to 130,000BCE, but the advent of remotely operated vehicles (ROVs) in the 1950s introduced technology that has had significant impact on ocean exploration. Today, ROVs play a critical role in both military (e.

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Accumulation of marine debris is a global problem that affects the oceans on multiple scales. The majority of floating marine debris is composed of microplastics: plastic particles up to 5 mm in diameter. With similar sizes and appearances to natural food items, these small fragments pose potential risks to many marine organisms including zooplankton and zooplanktivores.

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Plankton imaging systems are capable of providing fine-scale observations that enhance our understanding of key physical and biological processes. However, processing the large volumes of data collected by imaging systems remains a major obstacle for their employment, and existing approaches are designed either for images acquired under laboratory controlled conditions or within clear waters. In the present study, we developed a semi-automated approach to analyze plankton taxa from images acquired by the ZOOplankton VISualization (ZOOVIS) system within turbid estuarine waters, in Chesapeake Bay.

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Article Synopsis
  • The study examines the size of the largest marine megafauna, noting challenges in obtaining accurate measurements due to rarity and remoteness.
  • It reviews 25 species, documenting the largest known sizes, analyzing body size variation related to sex and environment, and identifying gaps in existing data.
  • The findings reveal significant variability in size distributions and provide allometric scaling equations for estimating sizes, while highlighting human impacts on size and geographic variations.
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The Deepwater Horizon Oil Spill resulted in the release of a large quantity of oil and gas into the northern Gulf of Mexico from a bathypelagic source. Due to a lack of pre-spill quantitative data the baseline condition of the communities near the spill site is unknown. This makes it difficult to determine the impact of the spill on deepwater megafauna.

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The deep-sea squid Grimalditeuthis bonplandi has tentacles unique among known squids. The elastic stalk is extremely thin and fragile, whereas the clubs bear no suckers, hooks or photophores. It is unknown whether and how these tentacles are used in prey capture and handling.

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Zooplankton in the ocean respond to visual and hydro-mechanical cues such as small-scale shear in turbulent flow. In addition, they form strong aggregations where currents intersect sloping bottoms. Strong and predictable tidal currents over a sill in Knight Inlet, Canada, make it an ideal location to investigate biological behaviour in turbulent cross-isobath flow.

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High-frequency acoustic scattering techniques have been used to investigate dominant scatterers in mixed zooplankton populations. Volume backscattering was measured in the Gulf of Maine at 43, 120, 200, and 420 kHz. Zooplankton composition and size were determined using net and video sampling techniques, and water properties were determined using conductivity, temperature, and depth sensors.

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An investigation of midwater zooplankton aggregations in a coastal fjord was conducted in November 2002. This study focused on quantitative comparisons between a calibrated, three-frequency (38, 120, and 200 kHz) vessel-based echo-sounder, a multinet towed zooplankton sampler (BIONESS), and a high-resolution underwater camera (ZOOVIS). Daytime layers of euphausiids and amphipods near 70-90-m depth were observed in lower parts of the inlet, especially concentrated by tidal flows around a sill.

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