Establishing rates of carbon sequestration in mangroves from an earthquake uplift event

Abstract

A contribution to the special feature 'Blue Carbon' organized by Catherine Lovelock.Electronic supplementary material is available online at https://doi.org/10.6084/m9.figshare. c.4444169.We assessed the carbon stocks (CS) in mangroves that developed after a magnitude 7.1 earthquake in Silonay, Oriental Mindoro, south Luzon, The Philippines in November 1994. The earthquake resulted in a 50 cm uplift of sediment that provided new habitat within the upper intertidal zone which mangroves colonized (from less than 2 ha pre-earthquake to the current 45 ha, 23 years post-earthquake). The site provided an opportunity for a novel assessment of the rate of carbon sequestration in recently established mangroves. The carbon stock was measured in above-ground, belowground and sediment compartments over a seaward to landward transect. Results showed a mean carbon stock of 549 + 30 Mg C ha 21 (of which 13% was from the above-ground biomass, 5% from the below-ground biomass and 82% from the sediments). There was high carbon sequestration at a 40 cm depth that can be inferred attributable to the developed mangroves. The calculated rate of C sequestration (over 23 years post-earthquake) was 10.2 + 0.7 Mg C ha 21 yr 21 and is comparable to rates reported from mangroves recovering from forest clearing. The rates we present here from newly developed mangroves contributes to calibrating estimates of total CS from restored mangroves (of different developmental stages) and in mangroves that are affected by disturbances.

Refining the Global Estimate of Mangrove Carbon Burial Rates Using Sedimentary and Geomorphic Settings

“…The 2012 data set included rates upwards of 800 g m −2 yr −1 from anthropogenically impacted systems such as the Jiulongjiang Estuary, China (Alongi et al., 2005) and Tamandaré, Brazil (Sanders et al., 2010). Recent mangrove OC burial data include the addition of similarly high burial rates greater than 800 g OC m −2 yr −1 from sites that include Jaguaripe Estuary, Brazil (Hatje et al., 2021); Luzon, Phillipines (Salmo et al., 2019); and Berau, Indonesia (Kusumaningtyas et al., 2019) that drive the increase in kurtosis of the global data (Figures 1a and 2). Several studies have attributed regional increases in mangrove OC and nutrient burial rates to eutrophication influences and anthropogenic development of coastlines (Perez et al., 2020; Sanders et al., 2014).…”

“…This is in agreement with a foundational definition of coastal eutrophication as an increase in the rate of sediment organic matter accumulation; Nixon (1995) proposed that coastal OC burial rates in excess of 500 g m −2 yr −1 should be classified not just as eutrophic, but as hypertrophic. However, the high burial rates of the most recent observations have not been attributed to eutrophication, but rather to variability in primary production and decomposition, hydrologic isolation, or high allochthonous inputs (Hatje et al., 2021; Kusumaningtyas et al., 2019; Salmo et al., 2019). Outlier analysis suggests that these higher values are unusual in the context of the rest of the global data.…”

IUCN Red List of Ecosystems, Mangroves of the Western Coral Triangle

“…Mg C ha -1 , with a maximum of 2,730 Mg C ha -1 (Murdiyarso et al, 2015). In contrast, the average ecosystem mangrove carbon in 37 disturbed sites studied in the Philippines was only 400 Mg C ha -1 , with a very wide range from 57.7 to 1,746.6 Mg C ha -1 , due to significant differences site to site in the degree of disturbance caused by typhoon damage or conversion to aquaculture ponds (Salmo and Gianan, 2019).…”