Nitrification, mediated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), is important in global nitrogen cycling. In estuaries where gradients of salinity and ammonia concentrations occur, there may be differential selections for ammonia-oxidizer populations. The aim of this study was to examine the activity, abundance, and diversity of AOA and AOB in surface oxic sedime...

Abstract Darwin Harbour is a working port and the most populated city in Northern Territory of Australia. This macrotidal estuary located wet–dry tropics Australia notwithstanding mounting development pressures region, largely unmodified. The prevailing oligotrophic condition estuarine waters suggest that biogeochemical cycling sediments remain active, buffering influence anthropogenic inputs. ...

The extraction of climatic signals from time series of biogeochemical data is further complicated in estuarine regions because of the dynamic interaction of land, ocean, and atmosphere. We explored the behavior of potential global and regional climatic stressors to isolate specific shifts or trends, which could have a forcing role on the behavior of biogeochemical descriptors of water quality a...

Estuarine and coastal systems represent a challenge when it comes to determining the causes of ecological change because human and natural perturbations often interact. Phytoplankton biomass (chlorophyll a) and group-specific photopigment indicators were examined from 1994 to 2007 to assess community responses to nutrient and climatic perturbations in the Neuse River Estuary, NC. This system ex...

Oysters are edible organisms that are often ingested partially cooked or even raw, presenting therefore a very high risk to the consumers' health, especially in tropical regions. The presence of Vibrio cholerae and Vibrio parahaemolyticus in oysters sampled at an estuary in the Brazilian northeastern region was studied, with 300 oysters tested through an 8-months period. The salinity of the wat...

The influence of seasonal environmental conditions on the formation and release of organic compounds by photosynthesizing phytoplankton was studied In a tropical estuary. The pattern of ''C fixat~on into the various intracellular compounds changed from pre-monsoon to monsoon depending on the quality and intensity of light available during the 2 seasons as well as phytoplankton composition. Duri...