Spatial and Temporal Dynamics of Primary Production in Antarctic Sea Ice

Spatial and Temporal Dynamics of Primary Production in Antarctic Sea Ice PDF Author: Benjamin Lundquist Saenz
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 242

Get Book Here

Book Description
Sea ice is an important driver of climate patterns and polar marine ecosystem dynamics. In particular, primary production by microalgae in sea ice has been postulated as a sink for anthropogenic CO2, and as a critical resource in the life cycle of Antarctic krill Euphausia superba, a keystone species. Study of the sea ice ecosystem is difficult at regional and global scales, however, because of the expense and logistical difficulties in accessing such a remote and hostile environment. Consequently, models remain valuable tools for investigations of the spatial and temporal dynamics of sea ice and associated ecology and biogeochemistry. Recent advances in model representations of sea ice have called into question the accuracy of previous studies, and allow the creation of new tools to perform mechanistic simulations of sea ice physics and biogeochemistry. To address spatial and temporal variability in Antarctic sea ice algal production, and to establish the bounds and sensitivities of the sea ice ecosystem, a new, coupled sea ice ecosystem model was developed. In the vertical dimension, the model resolves incorporated saline brine, macronutrients concentrations, spectral shortwave radiation, and the sea ice algae community at high resolution. A novel method for thermodynamics, desalination, and fluid transfer in slushy, high-brine fraction sea ice was developed to simulate regions of high algal productivity. The processes of desalination, fluid transfer, snow-ice creation, and superimposed ice formation allowed the evolution of realistic vertical profiles of sea ice salinity and algal growth. The model replicated time series observations of ice temperature, salinity, algal biomass, and estimated fluid flux from the Ice Station Weddell experiment. In the horizontal dimension, sub-grid scale parameterizations of snow and ice thickness allow more realistic simulation of the ice thickness distribution, and consequently, sea ice algal habitat. The model is forced from above by atmospheric reanalysis climatologies, and from below by climatological ocean heat flux and deep-water ocean characteristics. Areal sea ice concentration and motion are specified according to SSM/I passive microwave satellite estimates of these parameters. Sensitivity testing of different snow and ice parameterizations showed that without a sub-grid scale ice thickness distribution, mean ice and snow thickness is lower and bottom sea ice algal production is elevated. Atmospheric forcing from different reanalysis data sets cause mean and regional shifts in sea ice production and associated ecology, even when sea ice extent and motion is controlled. Snow cover represents a first-order control over ice algal production by limiting the light available to bottom ice algal communities, and changes to the regional, rather than mean, snow thickness due to the use of different ice and snow representations are responsible for large differences in the magnitude and distribution of sea ice algal production. Improved convective nutrient exchange in high-brine fraction (slush) sea ice is responsible for up to 18% of total sea ice algal production. A continuous 10-year model run using climatological years 1996-2005 produced a time series of sea ice algal primary production that varied between 15.5 and 18.0 Tg C yr-1. This study represents the first interannual estimate of Antarctic sea ice algal production that dynamically considers the light, temperature, salinity, and nutrient conditions that control algal growth. On average, 64% of algal production occurred in the bottom 0.2 m of the ice pack. Production was spatially heterogeneous, with little consistency between years when examined at regional scales; however, at basin or hemispheric scales, annual production was fairly consistent in magnitude. At a mean of 0.9 g C m-2 yr-1, the magnitude of carbon uptake by sea ice algae will not significantly affect the Southern Ocean carbon cycle. Light availability was the dominant control on sea ice algae growth over the majority of the year; however, severe nutrient limitation that occurred annually during late spring and summer proved to be the largest control over sea ice algal productivity.

Spatial and Temporal Dynamics of Primary Production in Antarctic Sea Ice

Spatial and Temporal Dynamics of Primary Production in Antarctic Sea Ice PDF Author: Benjamin Lundquist Saenz
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 242

Get Book Here

Book Description
Sea ice is an important driver of climate patterns and polar marine ecosystem dynamics. In particular, primary production by microalgae in sea ice has been postulated as a sink for anthropogenic CO2, and as a critical resource in the life cycle of Antarctic krill Euphausia superba, a keystone species. Study of the sea ice ecosystem is difficult at regional and global scales, however, because of the expense and logistical difficulties in accessing such a remote and hostile environment. Consequently, models remain valuable tools for investigations of the spatial and temporal dynamics of sea ice and associated ecology and biogeochemistry. Recent advances in model representations of sea ice have called into question the accuracy of previous studies, and allow the creation of new tools to perform mechanistic simulations of sea ice physics and biogeochemistry. To address spatial and temporal variability in Antarctic sea ice algal production, and to establish the bounds and sensitivities of the sea ice ecosystem, a new, coupled sea ice ecosystem model was developed. In the vertical dimension, the model resolves incorporated saline brine, macronutrients concentrations, spectral shortwave radiation, and the sea ice algae community at high resolution. A novel method for thermodynamics, desalination, and fluid transfer in slushy, high-brine fraction sea ice was developed to simulate regions of high algal productivity. The processes of desalination, fluid transfer, snow-ice creation, and superimposed ice formation allowed the evolution of realistic vertical profiles of sea ice salinity and algal growth. The model replicated time series observations of ice temperature, salinity, algal biomass, and estimated fluid flux from the Ice Station Weddell experiment. In the horizontal dimension, sub-grid scale parameterizations of snow and ice thickness allow more realistic simulation of the ice thickness distribution, and consequently, sea ice algal habitat. The model is forced from above by atmospheric reanalysis climatologies, and from below by climatological ocean heat flux and deep-water ocean characteristics. Areal sea ice concentration and motion are specified according to SSM/I passive microwave satellite estimates of these parameters. Sensitivity testing of different snow and ice parameterizations showed that without a sub-grid scale ice thickness distribution, mean ice and snow thickness is lower and bottom sea ice algal production is elevated. Atmospheric forcing from different reanalysis data sets cause mean and regional shifts in sea ice production and associated ecology, even when sea ice extent and motion is controlled. Snow cover represents a first-order control over ice algal production by limiting the light available to bottom ice algal communities, and changes to the regional, rather than mean, snow thickness due to the use of different ice and snow representations are responsible for large differences in the magnitude and distribution of sea ice algal production. Improved convective nutrient exchange in high-brine fraction (slush) sea ice is responsible for up to 18% of total sea ice algal production. A continuous 10-year model run using climatological years 1996-2005 produced a time series of sea ice algal primary production that varied between 15.5 and 18.0 Tg C yr-1. This study represents the first interannual estimate of Antarctic sea ice algal production that dynamically considers the light, temperature, salinity, and nutrient conditions that control algal growth. On average, 64% of algal production occurred in the bottom 0.2 m of the ice pack. Production was spatially heterogeneous, with little consistency between years when examined at regional scales; however, at basin or hemispheric scales, annual production was fairly consistent in magnitude. At a mean of 0.9 g C m-2 yr-1, the magnitude of carbon uptake by sea ice algae will not significantly affect the Southern Ocean carbon cycle. Light availability was the dominant control on sea ice algae growth over the majority of the year; however, severe nutrient limitation that occurred annually during late spring and summer proved to be the largest control over sea ice algal productivity.

Sea Ice

Sea Ice PDF Author: David N. Thomas
Publisher: John Wiley & Sons
ISBN: 1118778383
Category : Science
Languages : en
Pages : 666

Get Book Here

Book Description
Over the past 20 years the study of the frozen Arctic and Southern Oceans and sub-arctic seas has progressed at a remarkable pace. This third edition of Sea Ice gives insight into the very latest understanding of the how sea ice is formed, how we measure (and model) its extent, the biology that lives within and associated with sea ice and the effect of climate change on its distribution. How sea ice influences the oceanography of underlying waters and the influences that sea ice has on humans living in Arctic regions are also discussed. Featuring twelve new chapters, this edition follows two previous editions (2001 and 2010), and the need for this latest update exhibits just how rapidly the science of sea ice is developing. The 27 chapters are written by a team of more than 50 of the worlds’ leading experts in their fields. These combine to make the book the most comprehensive introduction to the physics, chemistry, biology and geology of sea ice that there is. This third edition of Sea Ice will be a key resource for all policy makers, researchers and students who work with the frozen oceans and seas.

U.S. Antarctic Program

U.S. Antarctic Program PDF Author:
Publisher:
ISBN:
Category : Antarctica
Languages : en
Pages : 52

Get Book Here

Book Description


Southern Ocean Ecology

Southern Ocean Ecology PDF Author: Sayed Z. El-Sayed
Publisher: Cambridge University Press
ISBN: 9780521443326
Category : Nature
Languages : en
Pages : 448

Get Book Here

Book Description
BIOMASS (Biological Investigations of Marine Antarctic Systems and Stocks) was a unique, large-scale, long-term, international research programme established in 1977 to investigate the ecology of the Southern Ocean. Its main aim was to gain a greater understanding of the biological systems and stocks in the marine Antarctic environment, thereby providing a sound basis for the future management of the living resources within this immense ocean. The programme was drawn to a close in 1991 and its completion marked by a colloquium which brought together key researchers to summarise and review the results obtained. This volume, arising from that colloquium, provides a succinct, state-of-the-art account of the ecology of the Southern Ocean and serves as a comprehensive record of this unique and successful international project.

Ocean Biogeochemistry

Ocean Biogeochemistry PDF Author: Michael J.R. Fasham
Publisher: Springer Science & Business Media
ISBN: 3642558445
Category : Science
Languages : en
Pages : 324

Get Book Here

Book Description
Oceans account for 50% of the anthropogenic CO2 released into the atmosphere. During the past 15 years an international programme, the Joint Global Ocean Flux Study (JGOFS), has been studying the ocean carbon cycle to quantify and model the biological and physical processes whereby CO2 is pumped from the ocean's surface to the depths of the ocean, where it can remain for hundreds of years. This project is one of the largest multi-disciplinary studies of the oceans ever carried out and this book synthesises the results. It covers all aspects of the topic ranging from air-sea exchange with CO2, the role of physical mixing, the uptake of CO2 by marine algae, the fluxes of carbon and nitrogen through the marine food chain to the subsequent export of carbon to the depths of the ocean. Special emphasis is laid on predicting future climatic change.

Antarctic Ecosystems

Antarctic Ecosystems PDF Author: Alex D. Rogers
Publisher: John Wiley & Sons
ISBN: 1444347225
Category : Science
Languages : en
Pages : 585

Get Book Here

Book Description
Since its discovery Antarctica has held a deep fascination for biologists. Extreme environmental conditions, seasonality and isolation have lead to some of the most striking examples of natural selection and adaptation on Earth. Paradoxically, some of these adaptations may pose constraints on the ability of the Antarctic biota to respond to climate change. Parts of Antarctica are showing some of the largest changes in temperature and other environmental conditions in the world. In this volume, published in association with the Royal Society, leading polar scientists present a synthesis of the latest research on the biological systems in Antarctica, covering organisms from microbes to vertebrate higher predators. This book comes at a time when new technologies and approaches allow the implications of climate change and other direct human impacts on Antarctica to be viewed at a range of scales; across entire regions, whole ecosystems and down to the level of species and variation within their genomes. Chapters address both Antarctic terrestrial and marine ecosystems, and the scientific and management challenges of the future are explored.

Space Remote Sensing of Subtropical Oceans (SRSSO)

Space Remote Sensing of Subtropical Oceans (SRSSO) PDF Author: Cho-Teng Liu
Publisher: Elsevier
ISBN: 008054150X
Category : Science
Languages : en
Pages : 275

Get Book Here

Book Description
This volume contains the proceedings from the COSPAR Colloquium on "Space Remote Sensing of Subtropical Oceans" which took place between 12 and 16 September, 1996, at the Institute of Oceanography of the National Taiwan University. Included are contributions addressing the issue, from scientific points of views, of why the first scientific satellite of Taiwan, ROCSAT-1, should be equipped with the Ocean Colour Imager (OCI) for oceanographic investigations.

Ross Sea Ecology

Ross Sea Ecology PDF Author: F.M. Faranda
Publisher: Springer Science & Business Media
ISBN: 364259607X
Category : Science
Languages : en
Pages : 594

Get Book Here

Book Description
The Antarctic represents the last of the world's still unexplored continents. Since 1985, Italy has sent 10 expeditions to this region, three of those have been exclusively devoted to research on the marine ecology of the Ross Sea region. This volume presents a global picture of this research. It includes contributions on water mass characteristics, particulate organic matter and nutrient utilization, and physiological aspects of primary production. Further topics are zooplankton, krill and top predator interactions in relation to physical and biological parameters, ecological features of coastal fish communities and the spatio-temporal variability of benthic biocenoses.

Antarctic Journal of the United States

Antarctic Journal of the United States PDF Author:
Publisher:
ISBN:
Category : Antarctica
Languages : en
Pages : 466

Get Book Here

Book Description


Polynyas: Windows to the World

Polynyas: Windows to the World PDF Author: Walker O. Smith Jr.
Publisher: Elsevier
ISBN: 0080522939
Category : Science
Languages : en
Pages : 475

Get Book Here

Book Description
Approx.474 pagesApprox.474 pages