Long-term thermal sensitivity of Earth’s tropical forests

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate

Distribution of Arsenic in the Sediments and Biota of Hilo Bay, Hawaii

Sediment samples collected from the Waiakea Mill Pond, Wailoa River, and Hilo Bay were analyzed for arsenic. Arsenic was detectable in 10of II sediment samples, and ranged in concentration from 2 to 715 ppm. Two species of plant and seven species of animal were collected from the Waiakea Mill Pond and analyzed for arsenic. No arsenic was detected in the plants, whereas four of the seven animal species had arsenic concentrations ranging from a trace to 1.3ppm. Sediments of the Wailoa River estuary have much higher concentrations of' arsenic than those of Hilo Bay, indicating that most arsenic is located near the original source of pollution, a factory that once operated on the shores of the Waiakea Mill Pond. Much of the arsenic is found in anaerobic regions of the sediment where it has been relatively undisturbed by biological activity. The low levels of arsenic in the biota of the estuary suggest that there is little remineralization of the region's arsenic and that it is trapped in anaerobic sediment layers

Long-term thermal sensitivity of Earth's tropical forests

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (-9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per degrees C in the hottest forests (&gt;32.2 degrees C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth's climate.</p

Data from Sullivan et al. (2020) Long-term thermal sensitivity of Earth’s tropical forests. Science. DOI: 10.1126/science.aaw7578.

ABSTRACT: The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater rate of decline in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate