scholarly journals Fire, hurricane and carbon dioxide: effects on net primary production of a subtropical woodland

2013 ◽  
Vol 200 (3) ◽  
pp. 767-777 ◽  
Author(s):  
Bruce A. Hungate ◽  
Frank P. Day ◽  
Paul Dijkstra ◽  
Benjamin D. Duval ◽  
C. Ross Hinkle ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Primary Production ◽  
Net Primary Production

scholarly journals Carbon dioxide flux and net primary production of a boreal treed bog: Responses to warming and water-table-lowering simulations of climate change

2015 ◽  
Vol 12 (4) ◽  
pp. 1091-1111 ◽  
Author(s):  
T. M. Munir ◽  
M. Perkins ◽  
E. Kaing ◽  
M. Strack
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Primary Production ◽  
Water Level ◽  
Water Table ◽  
Forest Floor ◽  
Net Primary Production ◽  
Control Site ◽  
Co2 Uptake ◽  
Experimental Site

Abstract. Midlatitude treed bogs represent significant carbon (C) stocks and are highly sensitive to global climate change. In a dry continental treed bog, we compared three sites: control, recent (1–3 years; experimental) and older drained (10–13 years), with water levels at 38, 74 and 120 cm below the surface, respectively. At each site we measured carbon dioxide (CO2) fluxes and estimated tree root respiration (Rr; across hummock–hollow microtopography of the forest floor) and net primary production (NPP) of trees during the growing seasons (May to October) of 2011–2013. The CO2–C balance was calculated by adding the net CO2 exchange of the forest floor (NEff-Rr) to the NPP of the trees. From cooler and wetter 2011 to the driest and the warmest 2013, the control site was a CO2–C sink of 92, 70 and 76 g m−2, the experimental site was a CO2–C source of 14, 57 and 135 g m−2, and the drained site was a progressively smaller source of 26, 23 and 13 g CO2–C m−2. The short-term drainage at the experimental site resulted in small changes in vegetation coverage and large net CO2 emissions at the microforms. In contrast, the longer-term drainage and deeper water level at the drained site resulted in the replacement of mosses with vascular plants (shrubs) on the hummocks and lichen in the hollows leading to the highest CO2 uptake at the drained hummocks and significant losses in the hollows. The tree NPP (including above- and below-ground growth and litter fall) in 2011 and 2012 was significantly higher at the drained site (92 and 83 g C m−2) than at the experimental (58 and 55 g C m−2) and control (52 and 46 g C m−2) sites. We also quantified the impact of climatic warming at all water table treatments by equipping additional plots with open-top chambers (OTCs) that caused a passive warming on average of ~ 1 °C and differential air warming of ~ 6 °C at midday full sun over the study years. Warming significantly enhanced shrub growth and the CO2 sink function of the drained hummocks (exceeding the cumulative respiration losses in hollows induced by the lowered water level × warming). There was an interaction of water level with warming across hummocks that resulted in the largest net CO2 uptake at the warmed drained hummocks. Thus in 2013, the warming treatment enhanced the sink function of the control site by 13 g m−2, reduced the source function of the experimental by 10 g m−2 and significantly enhanced the sink function of the drained site by 73 g m−2. Therefore, drying and warming in continental bogs is expected to initially accelerate CO2–C losses via ecosystem respiration, but persistent drought and warming is expected to restore the peatland's original CO2–C sink function as a result of the shifts in vegetation composition and productivity between the microforms and increased NPP of trees over time.

scholarly journals Carbon dioxide flux and net primary production of a boreal treed bog: responses to warming and water table manipulations

2014 ◽  
Vol 11 (9) ◽  
pp. 12937-12983 ◽  
Author(s):  
T. M. Munir ◽  
M. Perkins ◽  
E. Kaing ◽  
M. Strack
Keyword(s):  
Carbon Dioxide ◽  
Primary Production ◽  
Water Level ◽  
Water Table ◽  
Forest Floor ◽  
Net Primary Production ◽  
Carbon Dioxide Flux ◽  
Water Levels ◽  
Co2 Uptake ◽  
Experimental Site

Abstract. Mid-latitude treed bogs are significant carbon (C) stocks and are highly sensitive to global climate change. In a dry continental treed bog, we compared three sites; control, recent (1–3 years; experimental) and older drained (10–13 years; drained) with water levels at 38, 74 and 120 cm below the surface, respectively. At each site we measured carbon dioxide (CO2) fluxes and tree root respiration (Rr) (across hummock-hollow microtopography of the forest floor) and net primary production (NPP) of trees during the growing seasons (May to October) of 2011–2013. The carbon (C) balance was calculated by adding net CO2 exchange of the forest floor (NEff–Rr) to the NPP of the trees. From cooler and wetter 2011 to driest and warmest 2013, The control site was a~C sink of 92, 70 and 76 g m−2, experimental site was a C source of 14, 57 and 135 g m−2, and drained site was a progressively smaller source of 26, 23 and 13 g m−2, respectively. Although all microforms at the experimental site had large net CO2 emissions, the longer-term drainage and deeper water level at the drained site resulted in the replacement of mosses with vascular plants (shrubs) at the hummocks and lichens at the hollows leading to the highest CO2 uptake at drained hummocks and significant losses at hollows. The tree NPP was highest at the drained site. We also quantified the impact of climatic warming at all water table treatments by equipping additional plots with open-top chambers (OTCs) that caused a passive warming on average of ∼1 °C and differential air warming of ∼6 °C (at mid-day full sun) across the study years. Warming significantly enhanced the shrub growth and CO2 sink function of the drained hummocks (exceeding the cumulative respiration losses at hollows induced by the lowered water level × warming). There was an interaction of water level with warming across hummocks that resulted in largest net CO2 uptake at warmed drained hummocks. Thus in 2013, the warming treatment enhanced the sink function of control by 13 g m−2, reduced the source function of experimental by 10 g m−2, and significantly enhanced the sink function of the drained site by 73 g m−2. Therefore, drying and warming in continental bogs is expected to initially accelerate C losses via respiration but persistent drought and warming is expected to restore the peatland's original C sink function as a result of transitional shift of vegetation between the microforms and increased NPP of trees over time.

Microbial primary production and phototrophy

2018 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Carbon Dioxide ◽  
Primary Production ◽  
Microbial Mats ◽  
Higher Plants ◽  
Net Primary Production ◽  
Terrestrial Plants ◽  
Anoxygenic Photosynthesis ◽  
Photosynthetic Organisms ◽  
Anoxic Environments ◽  
Large Numbers

This chapter is focused on the most important process in the biosphere, primary production, the turning of carbon dioxide into organic material by higher plants, algae, and cyanobacteria. Photosynthetic microbes account for roughly 50% of global primary production while the other half is by large, terrestrial plants. After reviewing the basic physiology of photosynthesis, the chapter discusses approaches to measuring gross and net primary production and how these processes affect fluxes of oxygen and carbon dioxide into and out of aquatic ecosystems. It then points out that terrestrial plants have high biomass but relatively low growth, while the opposite is the case for aquatic algae and cyanobacteria. Primary production varies greatly with the seasons in temperate ecosystems, punctuated by the spring bloom when the biomass of one algal type, diatoms, reaches a maximum. Other abundant algal types include coccolithophorids in the oceans and filamentous cyanobacteria in freshwaters. After the bloom, small algae take over and out-compete larger forms for limiting nutrients because of superior uptake kinetics. Abundant types of small algae include two coccoid cyanobacteria, Synechococcus and Prochlorococcus, the latter said to be the most abundant photoautotroph on the planet because of its large numbers in oligotrophic oceans. Other algae, often dinoflagellates, are toxic. Many algae can also graze on other microbes, probably to obtain limiting nitrogen or phosphorus. Still other microbes are mainly heterotrophic but are capable of harvesting light energy. Primary production in oxic environments is carried out by oxygenic photosynthetic organisms, whereas in anoxic environments with sufficient light, it is anaerobic anoxygenic photosynthesis in which oxygen is not produced. Although its contribution to global primary production is small, anoxygenic photosynthesis helps us understand the biophysics and biochemistry of photosynthesis and its evolution on early Earth. These microbes as well as aerobic phototrophic and heterotrophic microbes make up microbial mats. These mats can provide insights into early life on the planet when a type of mat, “stromatolites,” covered vast areas of primordial seas in the Proterozoic.

Phytoplankton: Diatoms

2017 ◽  
Author(s):  
Alexandra Kraberg ◽  
Rowena Stern
Keyword(s):  
Carbon Dioxide ◽  
Life Cycle ◽  
Primary Production ◽  
Final Section ◽  
Net Primary Production ◽  
Carbon Dioxide Fixation ◽  
Tree Of Life ◽  
General Morphology ◽  
Family Level ◽  
Global Carbon

This chapter describes the taxonomy of diatoms, one of the most abundant and diverse (morphologically and genetically) phytoplankton groups. They are responsible for at least 25% of global carbon dioxide fixation and 20% of net primary production. It covers their life cycle, general morphology, and ecology and distribution. It includes a section that indicates the systematic placement of the taxon described within the tree of life, and lists the key marine representative illustrated in the chapter (usually to genus or family level). This section also provides information on the taxonomic authorities responsible for the classification adopted, and recent changes which might have occurred, and it lists relevant taxonomic sources. The final section describes and illustrates the genera or families in more detail by highlighting specific representatives on identification cards.

Sign in / Sign up

Export Citation Format

Share Document