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Archive for October, 2013

Deposition of dioxin from terrestrial emissions into the world's oceans over one year of atmospheric transport

Model Suggests 40% of Global Dioxin Emissions End Up in Oceans

Researchers at the University of British Columbia recently presented a global model simulating how dioxins, a group of very toxic, persistent pollutants, travel from source regions and are deposited around the globe. Their findings suggest that oceans are impacted more dramatically than previously thought.

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How will phytoplankton communities change in a warming world?

A global marine ecosystem model was used to predict how primary productivity and carbon export by phytoplankton will change in the next 100 years due to climate change.

Roughly 360 years ago, on the island of Santorini, Greece, a September afternoon sky was blotted out as metals tarnished and island inhabitants complained of terrible eye pain. By the time the skies cleared, approximately 70 people had died of asphyxiation. Today, this picturesque vacation destination is a mecca for honeymooners yearning for blue roofed, white stucco buildings overlooking Mediterranean sunsets. What tourists can’t see from their hotel windows is Santorini’s neighbor, Kolumbo, an underwater volcano 7km to the northeast.

Passing gas makes islanders feel a burn: CO2 degassing, low pH and the similarities between an underwater Greek volcano and two Cameroon lakes

Roughly 360 years ago, on a September afternoon in the Aegean sea, the sky was blotted out as metals tarnished and inhabitants complained of terrible eye pain. By the time the skies cleared on one island, roughly 70 people had died of asphyxiation. Today, the picturesque vacation destination is covered with blue roofed, white stucco buildings overlooking Aegean sunsets. What tourists can’t see from their hotel windows is the island’s neighbor, Kolumbo, an underwater volcano 7km to the northeast…

European Otter (Lutra lutra) and trends of some perfluorinated compounds (PFCs).

Disconcerting trends of pollutants in the Scandinavian Otter Population

Fluorinated compounds are an emerging class of persistent pollutants that have a global presence in the environment, biota, and humans, but are only now beginning to be regulated. A group of researchers from Scandinavia looked at liver samples taken from otters in Sweden and Norway from 1972-2011 and found that concentrations of many of these compounds have increased at disquieting rates, particularly within the last decade.

Figure 1. A geographical reconstruction of glacial Lake Agassiz's total extent over ~5,000 years.  Arrows represent possible drainage routes and numbers represent the location of paleoclimate studies cited.

Catastrophic floods or drought? What caused the water level drop of glacial Lake Agassiz?

Formed from the meltwater of a colossal ice sheet that once blanketed North America, glacial Lake Agassiz experienced a sudden drop in water level approximately 12,900 years ago. The timing of this event aligns with a climatic return to cold conditions for 1,000 years, known as the Younger Dryas. A well-established hypothesis suggests that catastrophic drainage of Lake Agassiz explains the drop in water level and the associated abrupt climate change. This hypothesis has been recently challenged, explaining the drop in water level as a climate shift to desert-like conditions. How well does this competing hypothesis hold up?

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Coral Reefs Suffering from Ocean Acidification

Researchers investigated natural trends in carbonate chemistry of the Davies Reef flat in the central Great Barrier Reef on diel and seasonal timescales. They found the reef flat is below a calcification threshold, which implies that a transition in the reef may occur from a state of net calcification to dissolution, around 26.9% of the time during the summer and 14.1% of the time in the winter.

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Fish follow climate velocities through space and time

We expect marine species to respond to climate change by either adapting or changing geographical ranges. But observed shifts in marine species distributions are often difficult to decipher, spanning a wide array of directions and rates. Most hypotheses focus on biological differences amongst species to explain changing distributions. The authors of this paper explored climate velocities – or, isotherms moving through space and time – as an explanation for changing species distributions.

Figure 1: Total abundance vs. ESD prevalence in southern New England (by sea sampling survey done by Rhode Island Department of Environmental Management)

Disease affects New England Lobsters

Lobster, an important crustaceous member of inshore rocky bottom ecosystems in southern New England and a favorite sweet-meated-treat of many New Englanders, has shown a decline in abundance corresponding with an increase in enzootic shell disease (ESD) since the early 1990s. Castro et al. reviewed fifteen years of research on ESD in Rhode Island’s Narragansett Bay to better understand what this means for fishery sustainability. Understanding the prevalence of ESD in lobster populations can improve policies implemented for lobster fisheries to maximize the catchable yield and sustain a fishable population in southern New England.

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Life in plastic, it’s fantastic…for microbes in the plastisphere

Scientists find a diverse and distinct community of microorganisms that live on plastic trash at the surface of the North Atlantic Ocean. Is the “plastisphere” only a buzzword? Or can plastic waste be considered a new, man-made ecological habitat in the open ocean?

Illustration of a blue whale earplug. (A) Schematic diagram showing the location of the earplug within the ear canal: (a) whale skull, (b) tympanic bulla, (c) pars flaccida/tympanic membrane (“glove finger”), (d) cerumen (earplug), (e) external auditory meatus, (f) auditory canal, (g) muscle tissue, (h) blubber tissue, and (i) epidermis. (B) Extracted blue whale earplug; total length 25.4 cm. (C) Earplug longitudinal cross-section. (D) View (20x) or earplug cross-section showing discrete laminae. (Trumble et al. 2013)

Ear wax holds untold treasures for whale researchers

Ingested contaminants, along with hormones, are preserved in the whale’s earplug. Unlike muscle and blubber, ear wax does not allow rapid biodegradation of compounds. This wax builds up in laminar layers throughout the whale’s lifetime, producing a timeline of the whale’s existence, much like tree rings.

Depth at marine bird observation sites within Glacier Bay grouped into 3 foraging classes.

Determining marine bird distribution in Glacier Bay, Alaska using fine spatial-scale hydrographic modeling

Researchers in Glacier Bay surveyed fifteen species of marine birds and linked the observations to instantaneous measurements of current speed and water surface elevation to determine how fine-scale tidal features influence bird distribution.

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