Geology topics

L.P. Jayatissa

Publications and source records attributed to L.P. Jayatissa.

3 recordsLinked to original sources

USGS2021

Scientific contributions of the Mangrove Macrobenthos and Management (MMM) conference series, 2000-2019

The conservation of mangrove forests has become an important international policy priority in recent decades, and is mirrored by a large increase in research interest. Multiple disciplines now use mangroves as a study system, from molecular biology to social science. The variety of research conducted in mangroves is exemplified by the Mangrove Macrobenthos & Management (MMM) conference series, the world's largest gathering of researchers and practitioners dedicated to the science and conservation of the mangrove ecosystem. Established in 2000, MMM is a useful barometer with which to identify and measure research trends over the last 20 years. This study describes the history of the MMM conference series, and analyses the research presented in this series as a potential proxy of how the broader mangrove research field has changed through time. Presentations in early MMM conferences were dominated by macrobenthos studies, reflective of the origins of MMM as a forum specifically for mangrove macrobenthos research. However, later conferences have come to reflect the broader interests of the mangrove research field, and have tracked the emergence of blue carbon and other ecosystem services. Mangrove forests continue to be a rich and diverse ecosystem of study, and future MMM conferences will continue to provide a platform for impactful research and management.

Estuarine, Coastal and Shelf Science↗

USGS2017

Impacts of mangrove density on surface sediment accretion, belowground biomass and biogeochemistry in Puttalam Lagoon, Sri Lanka

Understanding the effects of seedling density on sediment accretion, biogeochemistry and belowground biomass in mangrove systems can help explain ecological functioning and inform appropriate planting densities during restoration or climate change mitigation programs. The objectives of this study were to examine: 1) impacts of mangrove seedling density on surface sediment accretion, texture, belowground biomass and biogeochemistry, and 2) origins of the carbon (C) supplied to the mangroves in Palakuda, Puttalam Lagoon, Sri Lanka. Rhizophora mucronata propagules were planted at densities of 6.96, 3.26, 1.93 and 0.95 seedlings m −2 along with an unplanted control (0 seedlings m −2 ). The highest seedling density generally had higher sediment accretion rates, finer sediments, higher belowground biomass, greatest number of fine roots and highest concentrations of C and nitrogen (N) (and the lowest C/N ratio). Sediment accretion rates, belowground biomass (over 1370 days), and C and N concentrations differed significantly between seedling densities. Fine roots were significantly greater compared to medium and coarse roots across all plantation densities. Sulphur and carbon stable isotopes did not vary significantly between different density treatments. Isotope signatures suggest surface sediment C (to a depth of 1 cm) is not derived predominantly from the trees, but from seagrass adjacent to the site.

Puttalam Lagoon↗

USGS2010

High mangrove density enhances surface accretion, surface elevation change, and tree survival in coastal areas susceptible to sea-level rise

Survival, growth, aboveground biomass accumulation, sediment surface elevation dynamics and nitrogen accumulation in sediments were studied in experimental treatments planted with four different densities (6.96, 3.26, 1.93 and 0.95 seedlings m −2 ) of the mangrove Rhizophora mucronata in Puttalam Lagoon, Sri Lanka. Measurements were taken over a period of 1,171 days and were compared with those from unplanted controls. Trees at the lowest density showed significantly reduced survival, whilst measures of individual tree growth did not differ among treatments. Rates of surface sediment accretion (means ± SE) were 13.0 (±1.3), 10.5 (±0.9), 8.4 (±0.3), 6.9 (±0.5) and 5.7 (±0.3) mm year −1 at planting densities of 6.96, 3.26, 1.93, 0.95, and 0 (unplanted control) seedlings m −2 , respectively, showing highly significant differences among treatments. Mean (±SE) rates of surface elevation change were much lower than rates of accretion at 2.8 (±0.2), 1.6 (±0.1), 1.1 (±0.2), 0.6 (±0.2) and −0.3 (±0.1) mm year −1 for 6.96, 3.26, 1.93, 0.95, and 0 seedlings m −2 , respectively. All planted treatments accumulated greater nitrogen concentrations in the sediment compared to the unplanted control. Sediment %N was significantly different among densities which suggests one potential causal mechanism for the facilitatory effects observed: high densities of plants potentially contribute to the accretion of greater amounts of nutrient rich sediment. While this potential process needs further research, this study demonstrated how higher densities of mangroves enhance rates of sediment accretion and surface elevation processes that may be crucial in mangrove ecosystem adaptation to sea-level rise. There was no evidence that increasing plant density evoked a trade-off with growth and survival of the planted trees. Rather, facilitatory effects enhanced survival at high densities, suggesting that managers may be able to take advantage of high plantation densities to help mitigate sea-level rise effects by encouraging positive sediment surface elevation.

Puttalam Lagoon↗