Preface Preface of the First Edition Chapter 1: Introduction 1.1 Models of marine ecosystems 1.2 Models from nutrients to fish Chapter 2: Chemical-Biological Models 2.1 Chemical-biological processes 2.2 Simple models 2.3 Simple plankton models for the ocean Chapter 3: More Complex Models 3.1 Competition 3.2 Several functional groups 3.3 N2 fixation 3.4 Denitrification Chapter 4: Modelling Life Cycles of Copepods and Fish 4.1 Growth and stage duration 4.2 Stage-resolving models of copepods 4.3 Experimental simulations 4.4 A fish model Chapter 5: Physical-Biological Interaction 5.1 Irradiance 5.2 Coastal ocean dynamics 5.3 Advection-diffusion equation 5.4 Upscaling and downscaling 5.5 Resolution of processes Chapter 6: Coupled Models 6.1 Introduction 6.2 Regional to global models 6.3 Circulation models 6.4 Baltic sea 6.5 Description of the model system 6.6 Simulation of the annual cycle 6.7 Simulation of the decade 1980-1990 6.8 A load reduction experiment 6.9 Projection of future changes 6.10 Tracking of elements 6.11 Discussion Chapter 7: Circulation Model, Copepods and Fish 7.1 Recruitment (Match-Mismatch) 7.2 Copepods in the baltic sea model 7.3 Three-dimensional simulations 7.4 Modelling of behavioural aspects 7.5 Fish in a three-dimensional model 7.6 Ergom: A Biogeochemical Model for Regional Seas Chapter 8: A Brief Introduction to MATLAB 8.1 Fundamentals 8.2 Ordinary differential equations 8.3 Miscellaneous Appendix: Content of the Booksite Bibliography Index
Background. The purpose of this study was to explore the possible association between coronary artery disease (CAD) risk and cervical cancer.Methods. We used data from the National Health Insurance system of Taiwan to address the research topic. The exposure cohort contained 728 patients with cervical cancer. Each cancer patient was randomly frequency-matched with 4 participants by age, index-month, and index-year from the general population who did not have a cancer history before the index date (control group). Cox's proportion hazard regression analyses were conducted to estimate the relationship between cervical cancer and CAD risk.Results. Among patients with cervical cancer, the overall risk for developing CADs was significantly lower than that of the control group [adjusted hazard ratio (aHR): 0.57, 95% confidence interval (95% CI): 0.41-0.79]. Further analyses revealed that the lower risk was observed only in patients with older age (aHR: 0.57, 95% CI: 0.40-0.82), a shorter follow-up duration (aHR: 0.47, 95% CI: 0.31-0.72), or with estrogen supplements (aHR: 0.39, 95% CI: 0.22-0.68).Conclusions. The findings from this population-based study suggest that estrogen supplements are associated with a decreased CAD risk in patients with cervical cancer. (C) 2012 Elsevier Inc. All rights reserved.
Polynyas are common occurrences all around the Arctic and Antarctic. Coastal polynyas are generally highly productive, which can lead to substantial CO2 drawdown. Consequently, they are important sink regions for atmospheric CO2. Depending on the surface area, the timing, duration and other factors, large differences exist as to the importance of polynyas in a biogeochemical sense. In the Arctic, the North Water Polynya seems to be the most important one, while in the Antarctic the most important is the Ross Sea Polynya. Polynyas in the Arctic have been better investigated and therefore the important polynyas are described with some confidence as to accuracy and completeness. For the Antarctic, this only holds for the Ross Sea Polynya. For many other Antarctic polynyas, only incomplete information is available. This is true even for the large, well known Weddell Polynya of the 1970s, which represents one of the few open-ocean polynyas. Here its biogeochemical role is semi-quantitatively assessed by combining the physical data from the 1970s with the known distributions of biogeochemical properties from recent years. It is deduced that the Weddell Polynya was a significant one-time sink for anthropogenic CO2 and CFCs, with ensuing deep-sea sequestration. Notably, some coastal polynyas are instrumental in transferring anthropogenic CO2 from the ice-free shelves to the abyssal oceans.
Polynyas are areas of open water in ice-covered seas, and are important sites for enhanced water column and benthic production in both the Arctic and Antarctic. Research on polynyas during the last twenty years has allowed multi-disciplinary evaluation of processes in various polynyas, including the Northeast Water (NEW) polynya, North Water (NOW) polynya, St. Lawrence Island polynya (SLIP), and the Bathurst (BATH) polynya in the Arctic, and the Ross Sea polynya (RSP), McMurdo Sound polynya (MSP), and Terra Nova Bay (TNB) polynya in the Antarctic. Several other coastal polynyas around Antarctica have received limited study. Studies of benthic patterns and processes in polynyas indicate that faunal biomass, productivity, and carbon cycling are dependent on depth, season, ice cover, carbon supply, and hydrographic forcing. Polynyas generally have high primary productivity, which typically supports rich benthic communities through enhanced vertical carbon flux. Short and long-term indicators can provide a "foot print" of water column processes within polynyas, such as sediment community oxygen consumption and benthic biomass. Although zooplankton production directly influences the retentive nature of carbon in the euphotic zone, depth is the critical factor for the impact of net carbon export to the underlying benthos. We use a simple modeling exercise of two polynya case studies, the SLIP in the Arctic and RSP in the Antarctic, to evaluate export efficiency and benthic carbon cycling. Depth ultimately influences whether a polynya is a "retentive" versus "export" ecosystem, impacting the underlying benthic populations and associated carbon cycling. Defining polynyas and marginal ice zones as retentive versus export systems is potentially a powerful tool for understanding polar shelf processes, particularly when primary production is not measured simultaneously with benthic parameters.
Measurements of partial pressure of CO2 in surface waters (pCO2sw) and overlying air (pCO2air) were made intermittently in the central and western equatorial Pacific from January 1987 to January 2003. We estimated the long-term trend of the pCO2sw in the high nutrient low chlorophyll (HNLC) region and the western Pacific warm pool. The spatial distribution of pCO2sw in the HNLC region could be expressed as a linear function of sea surface temperature (SST) and concentration of macronutrients ([NO2−]+[NO3−]), and in the western Pacific warm pool as a function of SST and sea surface salinity (SSS). By using an average SST (27.4 °C) and concentration of nitrate and nitrite (3.9 μmol/kg) in the HNLC region and the average SST (29.6 °C) and SSS (34.29) in the western Pacific warm pool between 1987 and 2003, we obtained pCO2sw values for respective cruises. The growth rate of pCO2sw due to increases in atmospheric CO2 was calculated to be 1.4±0.5 μatm/yr in the HNLC region and 1.3±0.3 μatm/yr in the western Pacific warm pool. The sea−air CO2 flux in the equatorial Pacific since 1998 was evaluated by using underway pCO2sw data measured by Japan Meteorological Agency, Meteorological Research Institute (JMA/MRI), National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory (NOAA/PMEL), and NOAA, Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML). From 1998 to 2003 the sea−air CO2 flux in the equatorial Pacific (5°N–10°S, 140°E–90°W) showed lowest flux in January/February 1998 (0.1±0.1 Pg C/yr, 1997/98 El Niño), and highest (0.9±0.4 Pg C/yr) in January/February 2001, suggesting significant interannual variations in sea−air CO2 flux in the equatorial Pacific. In October 2002−January 2003, which was within a weak El Niño period, the CO2 flux in the equatorial Pacific was 0.5±0.3 Pg C/yr, almost same as that of the non-El Niño period. In this period, sea−air CO2 flux in the central and western equatorial Pacific decreased considerably to the same level of January/February 1998, but that in the eastern equatorial Pacific remained fairly constant.
Since 900,000 years the 100- and 41-kyr cycles of the ice volume dominate most of the climatic parameters. Exception occurs in the tropics, where some records exhibit stronger precession cycles. Primary productivity is one of these parameters. Late pleistocene quantitative changes in nannoplankton communities preserved in eight deep-sea cores are used to monitor primary productivity along the equator in the Indian and Pacific oceans. The precession-controlled changes, significantly present in these cores, are discussed here in detail. Primary production (PP) is highest during high precession times in most of the records, and during low precession time in the western Pacific warm pool (WPWP). The opposite response of the WPWP corresponds to the rocking of the east–west thermocline slope of the Indo-Pacific that strongly affects PP. These balance movements of the thermocline slope are linked to processes similar to the southern oscillation phenomenon but on a longer time scale and are labelled ENSO-like. The precession-induced ENSO-like variability precedes changes in the oxygen isotopic ratio, which indicates that it is not the result of ice sheet fluctuations. On the reverse, because deglaciations occur during the transition caused by the onset of El Niño-like phases that produce great transport of heat to the high latitudes, ENSO-like variability could be at the origin of late pleistocene deglaciations. The stack of all these PP records shows that the glacial PP was 50% (3.5 Giga ton of carbon) higher than the interglacials in the equatorial Indo-Pacific ocean.
Phytoplankton assemblages in polynyas are strongly impacted by the unique environment of those systems, and their growth and accumulation is always greater within a polynya than under heavy ice. The extent of this enhancement is dependent on the physical conditions of the polynya—the duration of the polynya's existence, the distribution of ice and snow, and the physical circulation within it. We review the polynyas in both Arctic and Antarctic waters that have been intensively studied and compare them with respect to biomass, daily productivity, chemical and physical constraints, annual productivity, export, and effects on food webs and the local biogeochemical cycles. We conclude that the most productive polynyas (the North Water polynya and the Ross Sea polynya) have remarkably similar short-term productivity, and the annual productivity and seasonal timing of both are also similar. However, the two have strong dissimilarities in modes of control and export. The ecological consequences of enhanced production within a polynya are also investigated, and appear to vary among polynyas. We suggest that the differences among polynyas within polar systems reflect the differences in large-scale physical forcing that exist across the Arctic and Antarctic, and that generalizations among polynyas need to encompass this variability.
The light use efficiency (LUE) approach using the normalized difference vegetation index (NDVI) is the simplest method to estimate terrestrial net primary production (NPP). A simple LUE-based model, which used LUEs of plants, solar radiation, NDVI and stress functions for soil water and air temperature, was applied to estimate global terrestrial NPP between 1982 and 1999. NDVI images were computed using channels 1 and 2 of the Advanced Very High Resolution Radiometer (AVHRR) produced by the Pathfinder AVHRR LAND (PAL) datasets, after a simple radiometric correction. Anomalies in time series of global average monthly NDVI of the original PAL data, which were probably caused by volcanic ashes exposed in the atmosphere by huge eruptions such as Pinatubo, were successfully reduced in the computed NDVI. The solar radiation, air temperature and soil water of NCEP/NCAR Reanalysis data were also used for the NPP estimation. LUEs were determined based on the maximum photosynthetic rate in the literature for 17 land cover types of the IGBP-DIS classification. NPP was also computed using a constant LUE for the global vegetation to understand the effects of multiple LUE-settings. As a result, global NPP was estimated at between 58.5 and 62.6 petagram (Pg) carbon in 1983 and 1998, respectively, for the multiple LUE-settings and between 51.0 and 54.8 Pg carbon in 1983 and 1991, respectively, for the constant LUE-setting. NPP increased about 0.1 Pg carbon annually (P<0.1) for the case of multiple LUE-settings and about 0.08 Pg carbon annually (not significant) for the case of constant LUE-setting. Carbon absorption by the terrestrial ecosystems in 1980s and 1990s are reported in a literature (Kalnay et al., 1996) based on an analysis of atmospheric CO2 concentration. The rate of change in carbon absorption observed in that study is similar to that of NPP by our estimation. Inter-annual changes in NPP varied from region to region. Most clear long-term increasing or decreasing trends of NPP appeared in semiarid areas. The inter-annual changes in NDVI seemed to relate most clearly to the inter-annual NPP changes in these areas among parameters used for the NPP estimation, which were NDVI, average monthly air temperature, volumetric soil water content and solar radiation.
Polynyas and the overlying atmosphere interact through a series of feedback mechanisms which impart a distinctive polar maritime character to the boundary layer over and downwind of the open water area. Enhanced turbulent fluxes across the ice-free interface introduce heat and moisture into the otherwise cold, dry polar atmosphere, modifying clouds through plume formation and radiative exchanges between the atmosphere and underlying surface. Anthropogenic aerosols of remote origin and local biogenic emissions provide additional direct and indirect radiative forcing, which may also influence precipitation rates, cloud optical depth, and ozone concentration. These combined effects modulate the efficacy of polar regions' ability to act as a "heat sink" for the climate system, establishing a link between the regional polynya meteorology and global conditions. Models, gridded analyses, and remotely-sensed and validating measurements which describe the meteorology and feedback mechanisms in and around polynyas are discussed in this chapter, with an outlook toward future efforts and novel measurement and analytical techniques.
Polynyas are considered model ecosystems for understanding high-latitude carbon cycling, especially with regards to climate-sensitivity of the biological pump. Explanations for highly efficient carbon export from polynyas and other marginal ice zones often focus on the balance of autotrophy and heterotrophy in these perennially cold ecosystems. The remineralization of algal production is controlled, at least in part, by the activities of pelagic heterotrophic bacteria. Here, we review these activities in both Arctic and Antarctic polynya ecosystems and include a discussion of commonly used methods. Recent research findings from the Northeast Water (NEW), North Water (NOW), and Ross Sea Polynya (RSP) programs are summarized and compared. Overall the pelagic bacteria of these ecosystems respond quickly to spring and summertime algal blooms, similar to their temperate counterparts. We find little evidence for growth rate limitation by low temperature, at least during the phytoplankton growing season. Despite sometimes significant rates of bacterivory and viral lysis, bacterial growth is fast enough for stocks to accumulate to levels similar to those observed in temperate oceans. Despite apparent differences in DOM cycling and availability, Arctic and Antarctic polynya bacteria are more similar than dissimilar in their seasonal activities. High-latitude food web structure, leading bacteria to a focus on hydrolysis and solubilization of particulate matter may partly explain this finding. We speculate about the impacts of global warming on these ecosystems and envision a scenario in which hemispheric differences in polynya microbial ecology and biogeochemical function will be amplified.
The decade of the 1990s was very likely the warmest of the second millennium. The 1990s was also characterized by one of the strongest El Niño-Southern Oscillation (ENSO) events of the twentieth century, which occurred in 1997–1998 and was followed by worldwide mass coral bleaching. In this study, we examined the signal-recording ability of Porites spp. corals by comparing high-resolution coral oxygen isotope (δ18O) records from the northwestern Pacific with instrumental records of these profound events of the 1990s. Temporal changes in coral skeletal δ18O records from Ishigaki Island, Japan, showed good agreement with instrumental records of sea-surface temperature (SST) because the effect of seasonal and interannual variations in salinity on the δ18O of seawater in that region was relatively small. In the northwestern equatorial Pacific, the cooler SST and relative drought-characterizing El Niño events were particularly well recorded by corals from the Philippines. These conditions were also faithfully recorded as distinct positive anomalies in coral δ18O records from Chuuk Atoll and Pohnpei Island in Micronesia. Bleached Porites spp. corals from Ishigaki Island, as well as corals from Pandora Reef of the Great Barrier Reef, Australia, showed a growth gap, indicating a substantial decrease in skeletogenesis during the 1997–1998 mass bleaching event. At Ishigaki Island and the Pacific side of the Philippine Islands, a decreasing trend in δ18Oc was found even over the relatively short period between 1980 and 2000 which may indicate an SST rise and/or surface-water freshening related to global warming. Our results demonstrate the potential of coral isotope records to serve as indicators of climatic change in the tropical and subtropical waters of the northwestern Pacific, where the number of coral records is still limited.
Polynyas in both the Arctic and Antarctic are known to be sites of substantial accumulations of top-trophic predators. Three polynyas (the Ross Sea polynya, the North Water polynya, and the Northeast Water polynya) are described in detail with regard to the distribution and activities of birds and marine mammals. The comparison shows that a substantial variation occurs both spatially and temporally among polynyas, but confirms that these regions are critical and active sites of material and energy transfer in polar systems.
Polynya models can be divided into two categories: polynya flux models and general circulation polynya models. Flux models predict the location of the polynya edge by postulating mass and momentum balances at the polynya edge that are based on the dynamic equations for frazil and consolidated new ice. The general circulation approach uses comprehensive dynamic-thermodynamic sea ice models to predict the ice concentration in a certain region and, from this, the evolution of the polynya, which is characterised as the oceanic area within which ice concentration is smaller than a given threshold (10%, say). In this chapter, we review the most recent literature on both polynya modelling approaches.
