Zonation and seasonality of benthic primary production and community respiration in tropical mangrove forests

Oecologia ◽  
1994 ◽  
Vol 98 (3-4) ◽  
pp. 320-327 ◽  
Author(s):  
D. M. Alongi
2006 ◽  
Vol 3 (4) ◽  
pp. 895-959 ◽  
Author(s):  
J.-P. Gattuso ◽  
B. Gentili ◽  
C. M. Duarte ◽  
J. A. Kleypas ◽  
J. J. Middelburg ◽  
...  

Abstract. One of the major features of the coastal zone is that part of its sea floor receives a significant amount of sunlight and can therefore sustain benthic primary production by seagrasses, macroalgae, microphytobenthos and corals. However, the contribution of benthic communities to the primary production of the global coastal ocean is not known, partly because the surface area where benthic primary production can proceed is poorly quantified. Here, we use a new analysis of satellite (SeaWiFS) data collected between 1998 and 2003 to estimate, for the first time at a nearly global scale, the irradiance reaching the bottom of the coastal ocean. The following cumulative functions provide the percentage of the surface of the coastal zone receiving an irradiance greater than Ez: PaNon-polar=28.80−16.69 log10(Ez)+0.84 log102(Ez)+0.83 log103(Ez) PaArctic=16.01−15.67 log10(Ez)+2.03 log102(Ez)+1.00 log103(Ez) Data on the constraint of light availability on the major benthic primary producers and net primary production are reviewed. Some photosynthetic organisms can grow deeper than the nominal bottom limit of the coastal ocean (200 m). The minimum irradiance required varies from 0.4 to 5.1 mol photons m−2 d−1 depending on the group considered. The daily compensation irradiance of benthic communities ranges from 0.24 to 4.4 mol photons m−2 d−1. Data on benthic irradiance and light requirements are combined to estimate the surface area of the coastal ocean where (1) light does not limit the distribution of primary producers and (2) net community production (NCP, the balance between gross primary production and respiration) is positive. Positive benthic NCP can occur over 37% of the global shelf area. The limitations of this approach, related to the spatial resolution of the satellite data, the parameterization used to convert reflectance data to irradiance, and the relatively limited biological information available, are discussed.


Author(s):  
Antonio Quesada ◽  
Eduardo Fernández-Valiente ◽  
Ian Hawes ◽  
Clive Howard-Williams

2014 ◽  
Vol 59 (5) ◽  
pp. 1555-1569 ◽  
Author(s):  
Karl M. Attard ◽  
Ronnie N. Glud ◽  
Daniel F. McGinnis ◽  
Søren Rysgaard

2016 ◽  
Vol 23 (1) ◽  
pp. 410 ◽  
Author(s):  
Leah Temper

The Tana Delta, on the east coast of Kenya near Somalia, comprises riverine mangrove forests, wetlands and rangelands and is home to a range of indigenous pastoralist, farmer and fisher communities, whose traditional multi-user livelihood strategies have helped preserve exceptional local biodiversity. This study assesses conflicts over biomass through an analysis of Human Appropriation of Net Primary Production (HANPP), an indicator used by system ecologists that quantifies human-induced changes on the productivity and harvest of biomass flows. HANPP is calculated by seeing how much of the net primary production (NPP) of biomass flows created through solar energy are appropriated by human activity, and how much is left in the ecosystems for other species. In this article we introduce calculations of the HANPP in political ecology by studying not only the distribution of biomass between humans and non-humans but also (and this is the main point) between different groups or social classes of humans. We also ask what alliances are being made to protect biodiversity and keep livelihoods intact. In a sugar cane plantation economy, biomass production and the proportion appropriated by humans may increase, the Orma pastoralists and the Pokomo farmers would be dispossessed, less biomass would be available for local 'wild' biodiversity, and a much larger proportion of the NPP would be exported as sugar or ethanol.Key words: Human appropriation of biomass; bioeconomy; biodiversity; property rights; pastoralists; sugar cane; wetlands.


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