The Influence of Deep Convection on Biologically Driven Carbon Sequestration in the Irminger Sea

The North Atlantic plays a key role in sequestering anthropogenic carbon. The biological carbon pump is one of the mechanisms by which carbon is sequestered in the ocean. Phytoplankton photosynthesize at the sea surface, and fix carbon dioxide into organic carbon, a fraction of which sinks to the deep ocean. For sinking carbon to be stored long-term (time scales \u3e 1 year), it must sink deeper than the winter ventilation depth before being respired. This study focuses on how deep winter ventilation (convective mixing to depths \u3e 1000 m) in the Irminger Sea influences the sequestration of carbon via the biological pump. We analyze a four-year continuous time series (September 2014 to June 2018) of temperature, salinity, dissolved oxygen, optical backscatter, and chlorophyll fluorescence depth profiles from 200 to 2,600 meters from the Apex Profiler Mooring at the Ocean Observatories Initiative (OOI) Global Irminger Sea Array (60.0°N, 39.5°W). Temperature, salinity, and dissolved oxygen data are used to identify the depth and timing of winter mixing. Using dissolved oxygen as a tracer for respiration of sinking organic matter, optical backscatter as a tracer of particulate organic matter, and chlorophyll as an indicator of surface-derived photosynthetic material, the amount of sinking organic carbon ventilated back to the atmosphere in winter, as well as the carbon that escapes below the winter ventilation depth, is evaluated. We present data collected during a research cruise to the Irminger Sea in June 2018, where we collected discrete samples to calibrate sensors on the OOI Apex Profiler Mooring, and determined variability in the depth of winter mixing across the Irminger basin (59.6˚ – 64.2˚ N and 21.9˚ – 41.4˚ W) using 20 depth profiles of temperature, salinity, and dissolved oxygen from CTD casts. Evidence of deep winter convection was found throughout the basin, though there is variability in the maximum depth of convection, ranging from 1100 to 1500 meters. Using the 2014-2018 time series of data collected by the profiler mooring, we found strong interannual variability in both winter ventilation depths and respiration rates from the in the Irminger Sea, with winter ventilation depths ranging from 800 to 1,150 meters over the four year time period, and depth-integrated respiration rates within the seasonally-ventilated thermocline ranging from 3.62 to 7.66 mol O2 m-2. We find the highest respiration rates in the upper thermocline which contribute the majority of the carbon that is released back into the atmosphere during mixing. We also find that winter ventilation depth influences how much carbon is ventilated into the atmosphere during winter mixing. This study shows the importance of year-round observations in order to better understand how deep convection influences carbon sequestration by the biological pump

Settler, Ancestor, Eastern White Pine: Living Histories in Northern New England

Eastern white pines (ewps) (have) grow(n) through the temporal and physical landscape now known as northern “New England” along with settlers who (have) shape(d) this place with the violence of settler colonialism and white supremacy. Settlers have severed and exploited human-tree relationships throughout the threads of revolution, wealth accumulation, industry, conservation, and death entangled in today’s political ecology. Using methods from history, autoethnography, and more-than-human/plant geographies, I position myself and case studies of two colonial settler ancestors in relation to ewps, focusing on places in Littleton MA, Burlington VT, Dover NH, Manchester VT, and Gilford, NH. I find that a “place praxis” which involves time, attention, and love in relationship with more-than-human beings can transform ways of being on and with land

Book Review: Domestic Violence and the Politics of Privacy

Review of Domestic Violence and the Politics of Privacy by Kristin A. Kell

On Treating A Survey Of Convenience Sample As A Simple Random Sample

Threat of bias has kept many from using data gathered in less than optimal conditions. We maintain that when convenience sampling represents race and gender at nearly correct proportions and can be beneficial, as these two variables are quite often used as stratification variables. We compared a convenience sample with a proven sample. Race and Sex were nearly proportional as was found in the proven sample. We conclude that the convenience sample can be used as though it is simple random

Shopping for Homes and Schools: A Qualitative Study of West Hartford, Connecticut

This qualitative study explores how access to public schooling is bought and sold in the real estate market in West Hartford, Connecticut, based on interviews with recent homebuyers

Ralph LeCocq\u27s First Employment Contract, August 1, 1912

Ralph\u27s first job after graduating law school. The contract was for working with E.P. Wanzer, Attorney for Plaintiff or Defendant, in Armour, South Dakota for one year to gain experience.https://nwcommons.nwciowa.edu/lecocqmiscellaneous/1024/thumbnail.jp

Missing the Goal: A Visual Guide to Sheff v. O\u27Neill School Desegregation: June 2007

This report provides and in-depth, spatial look at the Sheff v. O’Neill case. Including maps that show the racial make-up of the Sheff Region (22 districts around Hartford) throughout time, suburb participation in Project Choice and the districts that send students to magnet schools, the report takes a visual approach to data, translating numbers to colorful, descriptive maps. The report also includes a timeline of the case, a look at some traditional data tables, data presented several different ways and a discussion of the progress made toward the Sheff goals

A Test-Retest Transition Matrix: A Modification of McNemar’s Test

McNemar introduced what is known today as a test for symmetry in a two by two contingency tables. The logic of the test is based on a sample of matched pairs with a dichotomous response. In our example, the sample consists of the scores before and after an education program and the responses before and after the program. Each pair of scores is from only one person. The pretest divides the group of responders according to their answers to a dichotomous question. The posttest divides the two groups into two groups of like labels. The result is a two by two table. We construct a test of homogeneity, where the proportion of initially partitioned subjects will be equally distributed over the same partition after the program is completed, conditioned on the initial distribution