#Lake natron tanzania series#

The dates of these two extremes were found using the MODIS water product from the period 2013–2017.

Panel (a) shows the lake almost completely dry, panel (b) shows the lake at its maximum extent (see also Figs 5 and 6 of ref. Variations in water extent illustrated and derived from MODIS imagery (MODIS corrected reflectance imagery from NASA Worldview). We start with providing the necessary background information on the lake. 5 possible important sources and mechanisms driving the emissions. Based on the available data, we discuss in Sec. 4 we discuss surface emissivity features and provide the necessary spectroscopic evidence. This result leads to the question whether the observed NH 3 enhancements are actually genuine and not due to a surface retrieval artefact. We show that the largest NH 3 column loadings are observed over Natron’s exposed salt encrusted mudflats. 3 we analyse spatial and temporal patterns and link these with available hydrological parameters. In this paper, we use the 2008–2017 NH 3 IASI data and other publicly available datasets to help understand the nature of the emissions. Yearly averaged emission fluxes were estimated to be of the order of 15 kt/year (with an estimated lower and upper bound of 4 and 180 kt/year). The hotspot over Lake Natron, Tanzania (Figs 1 and 2) was the only one that was identified as having a natural origin. About one third of these hotspots were attributed to high-density animal farming, but surprisingly, the majority were linked to industrial activity, in particular to chemical fertilizer production plants. Careful analysis of this map revealed 248 NH 3 emission hotspots.

#Lake natron tanzania series#

Recently 13, a hyperresolved (0.01° × 0.01°) world map of NH 3 was presented, following the combined exploitation of all available IASI satellite data over ten years and a series of algorithmic improvements 14. Satellite measurements are currently available from four instruments: AIRS 9, TES 10, CrIS 11 and IASI 12. Sources of atmospheric ammonia include animal waste, fertilizers, combustion (biomass burning, waste burning, transport), industry (production of chemicals, manufacturing processes), soils, plants and oceans 3, 6, 7.Ībout a decade ago, it was discovered that infrared satellites can detect and measure atmospheric NH 3, which resulted in the first measurement-based global maps of its distribution 8. Largely due to the widespread availability of industrially fixed nitrogen 2, atmospheric emissions of NH 3 are increasing steadily 3, 4, with devastating effects on air quality, ecosystems and climate 5. As a by-product, we also show that hyperspectral infrared sounders such as IASI are capable of mapping different types of evaporative minerals such as trona and thermonatrite.Īmmonia (NH 3) plays a critical role in the global biogeochemical cycle of nitrogen 1 as one of the key components of reactive nitrogen. We formulate six processes that may explain why the largest losses are observed specifically over concentrated brines and/or exposed sediments. High temperatures and alkalinity are known to promote NH 3 losses from soda lakes.

The likely source of NH 3 at Lake Natron is decomposition of organic material, either from rivers and springs or produced in the lake (plankton, bird excreta). The timing is different from the agricultural dominated NH 3 emissions in the wider Natron area, which peak early in the year, after the first wet season. The largest NH 3 column loadings generally occur at the end of the dry season in September–November over Lake Natron’s largest mudflat, that is exposed with receding water levels. Temporal analysis reveals that the emissions are episodic and linked with the lake’s surface area. Here we explore 10 years of IASI NH 3 satellite data and other publicly available datasets over the area to characterize the natural NH 3 emissions in this unique ecosystem. Its remote location and the absence of nearby large anthropogenic sources suggest that the observed NH 3 is mainly of natural origin. The lake is in the centre of an endorheic (limited drainage) basin and has shallow, saline-alkaline waters. The list is based on available data and may be incomplete.In a recent global analysis of satellite-derived atmospheric NH 3 data, a hotspot was observed in the vicinity of Lake Natron, Tanzania. It does indicate whether each species is globally threatened or endangered according to the IUCN and also whether it is migratory, very rare, or accidental in the country.

The table below lists species recorded at this locale but does not indicate frequency of occurrence there.