Photosynthetic parameters of phytoplankton and sea ice algae from landfast sea ice of the Chukchi Sea off Point Barrow, Alaska, were assessed in spring 2005 and winter through spring 2006 using Pulse Amplitude Modulated (PAM) fluorometry including estimates of maximum quantum efficiency (F(v)/F(m)), maximum relative electron transport rate (rETR(max)), photosynthetic efficiency (alpha), and the photoadaptive index (E(k)). The use of centrifuged brine samples allowed to document vertical gradients in ice algal acclimation with 5 cm vertical resolution for the first time. Bottom ice algae (0-5 cm from ice-water interface) expressed low F(v)/F(m) (0.331-0.426) and low alpha (0.098-0.130 (micromol photons m(-2)s(-1))(-1)) in December. F(v)/F(m) and alpha increased in March and May (0.468-0.588 and 0.141-0.438 (micromol photons m(-2)s(-1))(-1), respectively) indicating increased photosynthetic activity. In addition, increases in rETR(max) (3.3-16.4 a.u.) and E(k) (20-88 micromol photons m(-2) s(-1)) from December to May illustrates a higher potential for primary productivity as communities become better acclimated to under-ice light conditions. In conclusion,photosynthetic performance by ice algae (as assessed by PAM fluorometry) was tightly linked to sea ice salinity, temperature, and inorganic nutrient concentrations (mainly nitrogen).
We derive the magnetic flux
Evolution, the photospheric velocity field, and the vertical electric current
Evolution. The magnetic configuration before the jets is derived by the
Nonlinear force-free field (NLFFF) extrapolation.
We derive that the jets are above a pair of parasitic magnetic bipoles...
I analyze the properties of accretion
disks in the Kerr-like metric proposed by Johannsen and Psaltis (2011), whose
inner edges are located at the radii where this vertical instability occurs. I
derive expressions of the energy and axial angular momentum of disk particles
that move on circular equat...
We know much less about how trabecular bone scales with BM than about how cortical bone scales with BM. We therefore conducted a meta-analysis of the existing literature to test in rodents, humans and other mammals, predicted scaling properties between BM and several trabecular parameters: bone volu...
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