Geology topics

Robert Eugene Turner

Publications and source records attributed to Robert Eugene Turner.

4 recordsLinked to original sources

USGS2026

Mangrove microbiomes as drivers of ecosystem recovery and restoration success

The microbes found in the rhizosphere, roots, leaves and stem surfaces and within the internal tissues of mangrove vegetation and their environment constitute the microbiome of the ecosystem. The organisms in the microbiome include bacteria, protozoa, fungi, algae, amoebas, and slime molds, which assist in maintaining and restoring mangrove ecosystems. This review explores the role of microbiomes in the maintenance of healthy mangrove ecosystems and in the successful restoration of degraded mangrove ecosystems. Microbes have important roles in several geomicrobiological cycles shaping mangrove ecosystems, including transforming nitrogen, phosphorus, carbon, sulfur and iron in biogeochemical cycles. Mangrove microbiomes contribute to the adaptation of vegetation to the harsh abiotic conditions in coastal areas, enhance nutrient uptake, produce plant-growth-promoting substances, and degrade the mangrove litter and the pollutants that can hinder restoration. Soil microbes function as biofertilizers, biopesticides, and bioremediation agents. The microbial diversity, composition, and functional capacity are important in the restoration of mangroves through their influence on voluntary recruitment following hydrologic restoration, on the establishment success of planted seeds and propagules, and on the survival of transplanted saplings and nursery-raised seedlings. The knowledge of the beneficial attributes of the microbiome can enhance the overall success of mangrove restoration. Identifying future needs, such as microbial inoculant validation, field-scale trials, and integration with hydrological restoration, are essential.

Microorganisms↗

USGS2026

Mangrove ecosystems: Importance, threats and opportunities for restoration

Mangroves are crucial for biodiversity conservation, coastal protection, and supporting local livelihoods. Mangroves may also protect coasts from storms and rising sea levels and can play a major role in climate mitigation. Threats to their health include activities such as infrastructural development, urban encroachment, aquaculture and crop farming, and oil and gas exploration. We review the threats and opportunities for the restoration of mangrove ecosystems on the coasts of Africa, which are highly impacted by oil spills. The most important challenge for mangrove restoration identified in this review is the restoration of appropriate hydrologic and salinity regimes prior to natural recruitment or the active planting of propagules.

Water↗

USGS2015

Nutrient-enhanced decomposition of plant biomass in a freshwater wetland

We studied soil decomposition in a Panicum hemitomon (Schultes)-dominated freshwater marsh located in southeastern Louisiana that was unambiguously changed by secondarily-treated municipal wastewater effluent. We used four approaches to evaluate how belowground biomass decomposition rates vary under different nutrient regimes in this marsh. The results of laboratory experiments demonstrated how nutrient enrichment enhanced the loss of soil or plant organic matter by 50%, and increased gas production. An experiment demonstrated that nitrogen, not phosphorus, limited decomposition. Cellulose decomposition at the field site was higher in the flowfield of the introduced secondarily treated sewage water, and the quality of the substrate (% N or % P) was directly related to the decomposition rates. We therefore rejected the null hypothesis that nutrient enrichment had no effect on the decomposition rates of these organic soils. In response to nutrient enrichment, plants respond through biomechanical or structural adaptations that alter the labile characteristics of plant tissue. These adaptations eventually change litter type and quality (where the marsh survives) as the % N content of plant tissue rises and is followed by even higher decomposition rates of the litter produced, creating a positive feedback loop. Marsh fragmentation will increase as a result. The assumptions and conditions underlying the use of unconstrained wastewater flow within natural wetlands, rather than controlled treatment within the confines of constructed wetlands, are revealed in the loss of previously sequestered carbon, habitat, public use, and other societal benefits.

Louisiana↗

USGS1983

Habitat Suitability Index Models: Northern Gulf of Mexico brown shrimp and white shrimp

A review and synthesis of existing information were used to develop estuarine habitat models for brown shrimp (Penaeus aztecus) and white shrimp (Penaeus setiferus). The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for estuarine areas of the northern Gulf of Mexico. Habitat suitability indexes are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service.

FWS/OBS↗