Floraciones de fitoplancton al borde del hielo en el Artico/Artic ice-edge phytoplankton blooms

Los actuales cambios climáticos en el Ártico helado, podrían tener un impacto significativo en la floración del fitoplancton, con implicaciones importantes para el ecosistema ártico.
Durante la primavera y verano árticos, el mar helado se funde y se fracciona. El agua dulce procedente del hielo fundido forma una capa y flota sobre el agua salada más densa que hay debajo. Esta estratificación de la columna de agua junto con la luz solar estacional provoca la floración del plancton, que a menudo forma largas y estrechas (20-100 km) bandas a lo largo del hielo que se retira. En el pasado, estas floraciones se estudiaban durante cruceros científicos y se centraron principalmente en regiones como el Mar de Barents entre Noruega y el archipiélago Svalbard o en el estrecho de Berng cerca de Alaska.
Las investigacionbes llevadas a cabo por Mahé Perrette, Andrew Yool, Graham Quartly y Ekaterina Popova del Centro Nacional de Oceanografía (Reino Unido) han utilizado moderna tecnología espacial (satélites SeaWiFs y MODIS) en combinación con información procedente del Centro Nacional de Datos de Hielo y Nieve (E.E.U.U.) para observar y seguir desde el espacio, floraciones en los bordes del hielo con alta resolución espacial sobre grandes áreas y a lo largo de largos periodos de tiempo.
Han encontrado que estas floraciones tienen lugar en el Artico de primavera a fines de verano en todas las zonas cubiertas estacionalmente de hielo . Se observaron floraciones en un 77-89% de las zonas para las que disponían de datos adecuados. Las floraciones alacanzaban su máximo 20 días después de la retirada del hielo, y formaban largas cintas o bandas, en ocasiones de más de 100 km) a lo largo del borde del hielo.
Según el Dr Yool, "nuestros hallazgos demuestran la fuerte conexión biofísica entre la propagación de las floraciones y la fusión del hielo, la cual es independiente de la dirección concreta de la retirada de hileo"
La importancia de estos hallazgos radica en que muestran que los futuros cambios del hielo ártico derivados del cambio climático, podrían tener un impacto significativo en la aparición de floraciones de fitoplancton, así como sobre los animales situados más arriba en la cadena alimentaria de la que dependen, como es el caso de los peces.

Ongoing climate-driven changes to the Arctic sea-ice could have a significant impact on the blooming of phytoplankton with important implications for the Arctic ecosystem.
During the Arctic spring and summer, sea-ice melts and breaks up. Freshwater from melting ice forms a blanket over the denser, saltier water below. This stratification of the water column, along with seasonal sunshine, triggers the appearance of phytoplankton blooms, which often form long but narrow (20-100 km) bands along the receding ice-edge. In the past they have been studied largely during reserachs cruises and were focused on regions such as the Barents Sea between Norway and the Svalbard Archipelago, and the Bering Shelf bordering Alaska.
The research conducted by Mahé Perrette, Andrew Yool, Graham Quartly and Ekaterina Popova of the National Oceanography Centre (UK), has used modern satellite technology (NASA's SeaWiFs and MODIS satellites) as well as information on sea ice concentrations obtained from the US National Snow and Ice Data Center (NSIDC), to observe and monitor ice-edge blooms at high spatial resolution over large areas and extended periods of time from space.
They found that ice-edge blooms occurred in the Artic in all seasonally ice-covered areas and from spring to late summer. They observed ice-edge blooms in 77-89% of locations for which they had adequate data. The blooms usually peaked within 20 days of ice retreat, sometimes forming long belts along the ice edge (greater than 100 km).
"Our findings demonstrate strong biophysical linkage between bloom propagation and sea-ice melt back, which is independent of the actual direction of retreat," said Dr Yool.
These findings are important because they indicate that future change in Arctic sea- ice resulting from climate change could significantly impact the occurrence of phytoplankton blooms as well as the animals further up the food chain that ultimately depend upon them, including fish.

Tomado de/Taken from Science Daily

La publicación completa/The full paper

Resumen de la publicación/Abstract of the paper
Near-ubiquity of ice-edge blooms in the Arctic
M. Perrette, A. Yool, G. D. Quartly and E. E. Popova1
Biogeosciences, 8, 515-524, 2011
www.biogeosciences.net/8/515/2011/
doi:10.5194/bg-8-515-2011
Abstract. Ice-edge blooms are significant features of Arctic primary production, yet have received relatively little attention. Here we combine satellite ocean colour and sea-ice data in a pan-Arctic study. Ice-edge blooms occur in all seasonally ice-covered areas and from spring to late summer, being observed in 77–89% of locations for which adequate data exist, and usually peaking within 20 days of ice retreat. They sometimes form long belts along the ice-edge (greater than 100 km), although smaller structures were also found. The bloom peak is on average more than 1 mg m−3, with major blooms more than 10 mg m−3, and is usually located close to the ice-edge, though not always. Some propagate behind the receding ice-edge over hundreds of kilometres and over several months, while others remain stationary. The strong connection between ice retreat and productivity suggests that the ongoing changes in Arctic sea-ice may have a significant impact on higher trophic levels and local fish stocks.