Analyzing the Effects of Coccolithophore Concentration on the Relationship Between Vertical Absorption Coefficient and Secchi Disk Depth

The study of how light passes through water, known as ocean optics, is useful in determining the constituents suspended at the surface of a water body. Understanding the composition of the water over time can answer questions about how the oceans have changed with global climate change and ocean acidification. The vertical absorption coefficient in ocean waters is an indicator characterizing how deeply light penetrates the water column. Using this information, scientists can better understand and predict the amount of primary productivity occurring in the area. Here we examine the relationship between vertical absorption coefficient and Secchi disk depth to determine if the concentration of a type of calcifying phytoplankton, coccolithophores, causes the relationship to deviate from the findings of a pivotal historical study conducted in 1929 by Poole and Atkins. Data was collected during July 2018 aboard the R/V Endeavor on the EN616 “Cocco-Mix” cruise in the Northwest Atlantic Ocean. Diffuse attenuation was determined using downwelling irradiance measurements gathered from a HyperPro that measures electromagnetic energy through the water column. Diffuse attenuation values were compared with Secchi disk depth measurements taken at the same time and location as the HyperPro casts. Results will contribute to our understanding of how the relationship between light extinction and Secchi disk depth changes between water bodies. This knowledge can be used to relate light extinction and Secchi disk depth in historical studies in the Northwest Atlantic that did not have access to more modern equipment to measure light extinction

Nanotechnology and azo-dyes in sweets

Nanotechnology is a fast growing field and consider as a key-technology of the 21st century. Nanoparticles are not only used in high-tech products or medical devices but are also more and more incorporated in food producers, for example in sweets. In addition, for food-coloring, azo-dyes are frequently used which makes an encounter of azo-dyes and nanoparticles unavoidable, The aim of this work was the isolation and characterisation of these dyes without including nanoparticles in a selected sweet product

Counteracting Green Alder Shrub Expansion by Low-Input Grazing

In the past decades, the decline of traditional agriculture has caused an abandonment of marginal pastures in many mountain areas of Europe. In the Swiss Alps, green alder (Alnus viridis) is the most abundant successional shrub. A survey of 24 pasture-shrub gradients showed that the encroachment by green alder, in contrast to other shrubs, is associated with a substantial decline in plant species richness. The understorey of alder is primarily populated by very few, broad-leaved herbaceous species benefitting from the atmospheric nitrogen fixed by actinomycetes in symbiosis with green alder. However, the understory vegetation also provides an underestimated forage, rich in protein and comparable in productivity and digestibility to nearby open pastures. A two-year grazing experiment with cattle (Dexter), sheep (local Engadine sheep) and mixed-breed goats in the Eastern Swiss Alps demonstrated that robust breeds were able to exploit these resources as they readily penetrated the thickets. The Engadine sheep and the goats consumed green alder bark and thus actively counteracted shrub encroachment. Dexter cattle did not forage on alder bark but on leaves and opened the thickets by their movement through them. Since goats preferred other woody species to green alder and depleted them before the alder, they may impair the regeneration of late-successional forest. Dexter heifers and Engadine lambs performed equally well on pastures with high shrub cover and on open pastures in terms of average daily weight gain, carcass and meat quality. This was facilitated by the comparatively low productivity of these breeds. In this way, low-input grazing systems utilizing adapted breeds, especially sheep, can add to conservation goals and sustain a viable meat production in marginal areas

Defensive responses of cuttlefish to different teleost predators

Author Posting. © Marine Biological Laboratory, 2013. This article is posted here by permission of Marine Biological Laboratory for personal use, not for redistribution. The definitive version was published in Biological Bulletin 225 (2013): 161-174.We evaluated cuttlefish (Sepia officinalis) responses to three teleost predators: bluefish (Pomatomus saltatrix), summer flounder (Paralichthys dentatus), and black seabass (Centropristis striata). We hypothesized that the distinct body shapes, swimming behaviors, and predation tactics exhibited by the three fishes would elicit markedly different antipredator responses by cuttlefish. Over the course of 25 predator-prey behavioral trials, 3 primary and 15 secondary defense behaviors of cuttlefish were shown to predators. In contrast, secondary defenses were not shown during control trials in which predators were absent. With seabass—a benthic, sit-and-pursue predator—cuttlefish used flight and spent more time swimming in the water column than with other predators. With bluefish—an active, pelagic searching predator—cuttlefish remained closely associated with the substrate and relied more on cryptic behaviors. Startle (deimatic) displays were the most frequent secondary defense shown to seabass and bluefish, particularly the Dark eye ring and Deimatic spot displays. We were unable to evaluate secondary defenses by cuttlefish to flounder—a lie-and-wait predator—because flounder did not pursue cuttlefish or make attacks. Nonetheless, cuttlefish used primary defense during flounder trials, alternating between cryptic still and moving behaviors. Overall, our results suggest that cuttlefish may vary their behavior in the presence of different teleost predators: cryptic behaviors may be more important in the presence of active searching predators (e.g., bluefish), while conspicuous movements such as swimming in the water column and startle displays may be more prevalent with relatively sedentary, bottom-associated predators (e.g., seabass).This project was funded by a United States Department of Defense, Defense Advanced Research Projects Agency, Defense Sciences Office (DARPA DSO) Grant (HR0011-09- 1-0017)