Mangrove forests are among the most productive ecosystems on Earth and mainly grow at tropical and subtropical latitudes. They provide many important ecological and societal functions. However, rapid spatiotemporal variations in mangroves have been observed worldwide, especially in the coastal zones of developing areas, and the integrity of mangroves has been significantly affected by anthropogenic activities in recent decades. The goal of this study was to determine the spatiotemporal characteristics of mangrove distribution over the past 30 years in Guangdong Province. This goal was achieved by classifying multi-temporal Landsat images using a decision tree method based on Classification and Regression Tree (CART) algorithm. The driving forces resulting in these spatiotemporal variations of mangroves were then discussed. Our analysis revealed that the classification method used in this study yielded good accuracy, with an overall accuracy and kappa coefficient of higher than 90% and 0.8, respectively. In Guangdong province, the mangrove forests covered areas of 9305, 9556, 6793, and 9700 ha in 1985, 1995, 2005, and 2015, respectively, with remarkable inter-annual changes. Mangrove forests are mainly located in Western Guangdong, and few are located in Eastern Guangdong. The distribution of mangrove patches became more fragmented from 1985 to 2005 and less fragmented from 2005 to 2015, and the distribution pattern in 2015 showed stronger connectivity than that in 1985. Natural factors, such as temperature, sea level rise, extreme weather events, and the length of the coastline, have macroscopic effects on the distribution of mangrove forests. Anthropogenic activities, such as deforestation, urbanization, and aquaculture development, have negative effects on the distribution of mangroves. On the other hand, the establishment of nature reserves has positive effects on the distribution of mangroves. The findings of this study provide a reference for the management and protection of mangroves, which is of great practical significance.

Total suspended solid (TSS) and chlorophyll‐a (Chl‐a) are critical indicators of water quality. Moderate‐resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite provides a critical tool to map TSS and Chl‐a on a daily basis. However, robust algorithms are required to retrieve TSS and Chl‐a from MODIS/Aqua images in the turbid Pearl River Estuary (PRE). Here, a new artificial neural network algorithm was developed to estimate TSS and Chl‐a in the PRE using a large amount of in situ measurements spanning more than a decade. Cross‐validation showed that the ANN‐based algorithm presented good performance with R²s of 0.73 and 0.66 for TSS and Chl‐a, respectively. The ANN‐based algorithm outperformed existing empirical and semi‐analytical algorithms. By implementing the proposed algorithm to MODIS/Aqua images, TSS and Chl‐a from August 2002 to July 2020 over the PRE were obtained. The results show that TSS decreased from northwest to southeast in all seasons while peaked in winter and summer. Chl‐a peaked in summer and the high Chl‐a patch transferred from the upper reach to the lower reach of the PRE with the increase of river discharge. TSS decreased at an annual rate of ∼0.13 mg L⁻¹ while Chl‐a increased at an annual rate of ∼0.05 mg m⁻³ in the last 18 years. Our findings suggest that machine learning provides a practical approach to estimate TSS and Chl‐a in turbid estuaries via MODIS/Aqua images and the approach developed in this study can be applied to other turbid waters with similar optical properties.

Post‐synaptic actions of glycine are terminated by specialized transporters. There are two genes encoding glycine transporters, GlyT1 and GlyT2. Glycine acts as a co‐agonist atN‐methyl‐d‐aspartate glutamatergic receptors (NMDARs). Blockage of GlyT1 enhances NMDAR function by controlling ambient glycine concentrations. Using whole‐cell patch‐clamp recordings of acute hippocampal slices, we investigated NMDAR kinetics of CA1 pyramidal neurons of mice expressing 50% of GlyT1 (GlyT1+/−). In this study, we report that the glycine modulatory site of the NMDAR at CA1 synapses is saturated in GlyT1+/− but not in wild‐type (WT) mice. We also found that the effect of ifenprodil, a highly selective NR2B‐containing‐NMDAR antagonist, is significantly reduced at CA1 synapses in GlyT1+/− compared to WT mice while immunoblotting experiments do not show significant differences for NR1, NR2A‐B‐C‐D subunits in both types of mice, suggesting alteration in NR2B‐containing‐NMDAR localization under a state of chronic saturating level of endogenous glycine. Using a pharmacological approach with MK‐801 and DL‐TBOA, we discriminated synapticvis‐à‐visextra‐synaptic NMDARs. We found that NR2B‐containing‐NMDARs are expressed at a higher level in the extra‐synaptic area of CA1 pyramidal neurons from GlyT1+/− compared to WT mice. Our results demonstrate that chronic saturating level of glycine induces significant changes in NMDAR localization and kinetic. Therefore, results from our study should help to gain a better understanding of the role of glycine in pathological conditions.