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OFI mobilizes knowledge by sharing the results of our research through contributions in journals, books, papers and other scientific publications.

Climate change threatens the world’s marine protected areas

A paper co-authored by OFI researcher — and Memorial University Associate Professor — Amanda Bates, is warning marine protected areas (MPAs) are increasingly at risk from climate change. Although MPAs are a primary management tool for mitigating threats to marine biodiversity, she says the warming associated with continued “business as usual” emissions will likely result in further habitat and species loss.

The team behind the paper pulled data from MPA sites around the world to create a global framework to examine environmental conditions in MPAs. They saw that the sites were undergoing rapid warming, the same as in other areas.

Read the full paper, published in Nature Climate Change ...


Dangerous ocean heat waves 

Heat waves in the ocean are happening more frequently and lasting longer than they did a century ago, concludes an OFI researcher in a new study published in Nature Communications

Eric Oliver, an assistant professor of oceanography at Dalhousie University and the lead author of the study, said in the early 20th century, there was an average of two marine heat waves per year globally, but now there are three or four. While they used to last 10 days on average, they now last for an average of 13 or 14 days.

Longer and more frequent marine heatwaves over the past century

Heatwaves are important climatic extremes in atmospheric and oceanic systems that can have devastating and long-term impacts on ecosystems, with subsequent socioeconomic consequences. Recent prominent marine heatwaves have attracted considerable scientific and public interest. Despite this, a comprehensive assessment of how these ocean temperature extremes have been changing globally is missing. Using a range of ocean temperature data including global records of daily satellite observations, daily in situ measurements and gridded monthly in situ-based data sets, the author's writers identify significant increases in marine heatwaves over the past century: from 1925 to 2016, global average marine heatwave frequency and duration increased by 34% and 17%, respectively, resulting in a 54% increase in annual marine heatwave days globally. 


Estimation of Transmittance of Solar Radiation in the Visible Domain Based on Remote Sensing: Evaluation of Models Using In Situ Data

OFI Scientific Director, Marlon Lewis, co-authored a paper that appeared in AGU Publications in January 2017. 

Key Points

  • The vertical distribution of solar radiation in the visible domain estimated from models using remote
    sensing data as input is evaluated
  • The best performance was provided by a scheme centered on the Inherent Optical Properties (IOPs)
  • The mean uncertainty of the estimated transmittance for a range of 0.1–100% is 23% from the IOPs
    system and insensitive to water types 

Closure and uncertainty assessment for ocean color reflectance using measured volume scattering functions and reflective tube absorption coefficients with novel correction for scattering

Understanding how the different components of seawater alter the propagation of incident sunlight through scattering and absorption is essential to using remotely sensed ocean color observations effectively. This is particularly apropos in heterogeneous coastal waters, where the different optically significant components (phytoplankton, detrital material, inorganic minerals, etc.) vary widely in concentration, often independently from one another.

Published in Applied Optics, Jan. 1, 2017. One of the authors is Marlon Lewis, OFI Scientific Director.

Read the full findings ...


Validation of Ocean Color Remote Sensing Reflectance Using Autonomous Float

This paper, published in the Journal of Atmospheric and Oceanic Technology, explores the use of autonomous profiling floats for in situ radiometry measurements. By drifting freely in the ocean and moving vertically by changing their buoyancy, profiling floats allow coverage of a wide range of locations, ocean optical properties, and atmospheric conditions. One of the authors is Marlon Lewis, OFI's Scientific Director.

Methods
Researchers used a set of six autonomous profiling floats deployed in the Mediterranean Sea, Pacific Ocean, and Atlantic Ocean to estimate radiometric quantities.

Read the full publication ...

A float after recovery
The optics package is the black body attached to the side of the float. The radiometers are marked with arrows (red: downwelling irradiance, orange: upwelling radiance). Photograph by Florent Besson.



Hyperspectral absorption and backscattering coefficients of bulk water retrieved from a combination of remote-sensing reflectance and attenuation coefficient

OFI researcher, Jungfang Lin, co-authored this paper which presents an updated scheme to derive hyperspectral a and bb with remote-sensing reflectance (Rrs)and diffuse attenuation coefficient (Kd) as the inputs.


Global Carbon Cycling on a Heterogeneous Seafloor

Diverse biological communities mediate the transformation, transport, and storage of elements fundamental to life on Earth, including carbon, nitrogen, and oxygen. However, global biogeochemical model outcomes can vary by orders of magnitude, compromising capacity to project realistic ecosystem responses to planetary changes, including ocean productivity and climate.

Carbon-Cycling-graphic.jpg#asset:334In this report, researchers — including OFI's Paul Snelgrove — compare global carbon turnover rates estimated using models grounded in biological versus geochemical theory and argue the turnover estimates based on each perspective yield divergent outcomes. Importantly, empirical studies that include sedimentary biological activity vary less than those that ignore it. Improving the relevance of model projections and reducing uncertainty associated with the anticipated consequences of global change requires reconciliation of these perspectives, enabling better societal decisions on mitigation and adaptation.







Taking the Pulse and Temperature of the North Atlantic Ocean

Observation is fundamental to understanding the ocean and forecasting its future and improving ocean health and promoting sustainable management. The Journal of Ocean Technology 2017 has published The GO-SHIP A02 Survey written by Evin McGovern, Caroline Cusack, Peter Croot, and OFI researcher and Dalhousie University professor, Doug Wallace.

The full report can be found here ...

Additional information:


Taking the Ocean’s Pulse: A Vision for the Canadian Biogeochemical Argo Program (2017)

By Katja Fennel, Blair Greenan and participants of the Canadian BGC Argo Workshop

About this paper: The ocean’s biogeochemical properties are changing rapidly with profound impacts on ecosystems and climate. In January 2017, a group of scientists from the Canadian federal government and universities gathered to discuss opportunities for Canada that arise from the international BGC-Argo initiative.

Recommendations:

  1. Actively strive to maintain and enhance Canada's position as an international leader in ocean observation through strong participation in the global BGC-Argo program.
  2. Enhance Canadian scientific capacity in biogeochemical modelling and prediction in order to capitalize fully on the potential of BGC-Argo.
  3. For Canada to reap maximum scientific and societal benefit from BGC-Argo, ample training opportunities for young scientists should be provided, which would also help ensure “eyes are on the data” at all times.
  4. Ensure free and near real-time access to the emerging data streams through properly resourcing data management.
  5. Form a national BGC-Argo steering committee to facilitate communication within the Canadian user community.

The full report is available here …