Methane flux from mangrove sediments along the southwestern coast of Puerto Rico

Journal Article · Tue Mar 01 00:00:00 EST 1994 · Estuaries; (United States)

DOI:https://doi.org/10.2307/1352563· OSTI ID:7159277

Sotomayor, D; Corredor, J E; Morell, J M ^[1]

---

1. Univ. of Puerto Rico, Mayagueez (Puerto Rico)

Although the sediments of coastal marine mangrove forests have been considered a minor source of atmospheric methane, these estimate have been based on sparse data from similar areas. We have gathered evidence that shows that external nutrient and freshwater loading in mangrove sediments may have a significant effect on methane flux. Experiments were performed to examine methane fluxes from anaerobic sediments in a mangrove forest subjected to secondary sewage effluents on the southwestern coast of Puerto Rico. Emission rates were measured in situ using a static chamber technique, and subsequent laboratory analysis of samples was by gas chromatography using a flame ionization detector. Results indicate that methane flux rates were lowest at the landward fringe nearest to the effluent discharge, higher in the seaward fringe occupied by red mangroves, and highest in the transition zone between black and red mangrove communities, with average values of 4 mg CH[sub 4] m[sup [minus]2] d[sup [minus]1], 42 mg CH[sub 4] m[sup [minus]2] d[sup [minus]1], and 82 mg CH[sub 4] m[sup [minus]2] d[sup [minus]1], respectively. Overall mean values show these sediments may emit as much as 40 times more methane than unimpacted pristine areas. Pneumatophores of Aviciennia germinans have been found to serve as conduits to the atmosphere for this gas. Fluctuating water level overlying the mangrove sediment is an important environmental factor controlling seasonal and interannual CH[sub 4] flux variations. Environmental controls such as freshwater inputs and increased nutrient loading influence in situ methane emissions from these environments. 34 refs., 3 figs., 3 tabs.

• OSTI ID: 7159277
• Journal Information: Estuaries; (United States), Vol. 17:1B; ISSN 0160-8347
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
COASTAL REGIONS
FORESTS
EUTROPHICATION
BIOLOGICAL EFFECTS
METHANE
EMISSION
PUERTO RICO
LOADING
MANGROVES
SEDIMENTS
SEWAGE
WATER POLLUTION
ALKANES
DEVELOPED COUNTRIES
GREATER ANTILLES
HYDROCARBONS
ISLANDS
LATIN AMERICA
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MATERIALS HANDLING
NORTH AMERICA
ORGANIC COMPOUNDS
PLANTS
POLLUTION
TREES
USA
WASTES
WEST INDIES
560300* - Chemicals Metabolism & Toxicology