Biomass recovery of coastal young mangrove plantations in Central Thailand.

Around one-third of the world's most carbon-rich ecosystems, mangrove forests, have already been destroyed in Thailand owing to coastal development and aquaculture. Improving these degraded areas through mangrove plantations can restore various coastal ecosystem services, including CO absorption and protection against wave action. This study examines the biomass of three coastal mangrove plantations (Avicennia alba) of different ages in Samut Prakarn province, Central Thailand.

Determinants of Microbial-Derived Dissolved Organic Matter Diversity in Antarctic Lakes.

Identifying drivers of the molecular composition of dissolved organic matter (DOM) is essential to understand the global carbon cycle, but an unambiguous interpretation of observed patterns is challenging due to the presence of confounding factors that affect the DOM composition. Here, we show, by combining ultrahigh-resolution mass spectrometry and nuclear magnetic resonance spectroscopy, that the DOM molecular composition varies considerably among 43 lakes in East Antarctica that are isolated from terrestrial inputs and human influence. The DOM composition in these lakes is primarily driven by differences in the degree of photodegradation, sulfurization, and pH.

Dissolved Organic Matter Processing in Pristine Antarctic Streams.

Accelerated glacier melt and runoff may lead to inputs of labile dissolved organic matter (DOM) to downstream ecosystems and stimulate the associated biogeochemical processes. However, still little is known about glacial DOM composition and its downstream processing before entering the ocean, although the function of DOM in food webs and ecosystems largely depends on its composition. Here, we employ a set of molecular and optical techniques (UV-vis absorption and fluorescence spectroscopy, H NMR, and ultrahigh-resolution mass spectrometry) to elucidate the composition of DOM in Antarctic glacial streams and its downstream change.

Ammonia Oxidation Potentials and Ammonia Oxidizers of Lichen-Moss Vegetated Soils at Two Ice-free Areas in East Antarctica.

The maximum ammonia oxidation potential (AOP) of a topsoil in Langhovde, East Antarctica was 22.1±2.4‍ ‍ng N g dry soil h (2‍ ‍mM ammonium, 10°C, n=3).

Origin, distributions, and environmental significance of ubiquitous humic-like fluorophores in Antarctic lakes and streams.

This study characterized dissolved organic matter (DOM) obtained from 47 lakes and 2 streams on ice-free areas at Lützow-Holm Bay and Amundsen Bay in East Antarctica (n = 74), where few biogeochemical studies have been historically conducted. Samples were analyzed for basic water chemistry and by resin fractionation, UV-vis spectroscopy, and excitation emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC). Salinity of the samples ranged very broadly from fresh to hypersaline as a result of evaporative concentration.

Dissolved organic matter distribution and its association with colloidal aluminum and iron in the Selenga River Basin from Ulaanbaatar to Lake Baikal.

The Selenga River Basin (Mongolia and Russia) has suffered from heavy metal contamination by placer gold mining and urban activities in recent decades. The objectives of this study were to provide the first distribution data of dissolved organic matter (DOM) and humic substances (HS) in this data-scarce region, and to investigate their association with dissolved and colloidal metals. Two sampling campaigns were conducted in August of 2013 and 2014.

High salinity leads to accumulation of soil organic carbon in mangrove soil.

Although mangrove forests are one of the most well-known soil organic carbon (SOC) sinks, the mechanism underlying SOC accumulation is relatively unknown. High net primary production (NPP) along with the typical bottom-heavy biomass allocation and low soil respiration (SR) have been considered to be responsible for SOC accumulation. However, an emerging paradigm postulates that SR is severely underestimated because of the leakage of dissolved inorganic carbon (DIC) in groundwater.

Evaluation of salinity effect on quantitative analysis of aquatic humic substances using nonionic DAX-8 resin.

A nonionic macroporous resin, Amberlite(®) XAD-8, or its substitute, Supelite™ DAX-8, is used when isolating or quantifying aquatic humic substances (AHS). However, the effect of salinity on the adsorption behavior of AHS onto the resin is yet to be confirmed, rendering the possibility of salinity-induced changes in the values of quantified amounts or characteristics of AHS obtained from a salty system. To verify the results of quantification and isolation of AHS using the resin in different salinity systems, the effect of salinity on such quantitative analyses of AHS has been examined.