Effects of natural gas pipeline condensate and crude oil spills, and comments on remediation, with emphasis on south Louisiana salt marshes: a review

This report reviews some of the natural ecological processes at work within a salt marsh as they relate to a spill of natural gas condensate - a mixture of aliphatic hydrocarbons, n-hexane, benzene, toluene, and xylene. It also reviews the environmental impacts of some of the components of natural gas condensate as well as related compounds (crude oil, higher molecular weight hydrocarbons, polycyclic aromatic hydrocarons - PAHs, linear alkyl-benzenes - LABs, etc.) on salt marsh ecosystems in southern Louisiana and elsewhere in the world. The behavior and persistence of these compounds once they have entered the environment is also considered.

The survival and growth of hybrid Clarias gariepinus and Heterotis longifilis fed with live and frozen Dapthnids

Six glass tanks, each containing dechlorinated tap water and stocked with 3-day-old Heterobranchus, larvae hybrid between, Heterobranchus longifilis (male and Clarias gariepinus (female) were administered two types of feeding trials viz: live and frozen Dapthnids. Each treatment was replicated three times. The larvae were each fed approximately 50 Dapthnids per feeding time for fifteen days. Morphometric measurements of weigh and total length were taken before and after the experiment, and water quality parameters were monitored throughout the experimental period. At the end of the experiment, fish larvae fed frozen, Dapthnids, showed higher survival rate than Heterobranchus fed live Dapthnids. Even though the statistical analysis revealed that there was no significant difference (P>0.05) in survival. However, the Heteroclarias fed live dapthnids performed better in terms of growth rate than Heteroclarias fed frozen dapthnids. The statistical analysis did not show significant difference (P>0.05) between the final length and weight of two treatments. Heteroclarias fed live dapthnids had higher length and weight than Heteroclarias fed frozen dapthnids. It was therefore concluded that based on this experiment there is the likelihood that frozen zooplankton (Daphnids) do not encourage growth of Heteroclarias, but improves its survival. However, it's suggested that frozen zooplankton can be used to supplement live zooplankton in situation of sacrcity

Natural habitat and population control mechanism of Crassula helmsii (Australian Swamp Stonecrop) in Australia

The plant Crassula helmsii (Kirk) Cochayne, was likely to become widely distributed and to dominate many damp and wet areas of nature reserves, recreational waters and agricultural drainage of Britain. The aim of this report was to study Australian Swamp Stonecrop in its natural habitat where it is in balance with its environment. This contrasts with its rapid and widespread distribution in the U.K. where its growth interferes with the use of fisheries and amenity lakes but also reduces the value of nature reserves and sites of special scientific interest by suppressing native flora. It was proposed to observe its growth at a variety of sites over its natural distribution and to include some environmental factors, e.g. water-level, water-chemistry (nutrients, acidity and alkalinity), frost-tolerance, salinity, with the help of portable sensors, locally-available services or data. 8 weeks of travel in Australia allowed time to study the plant in its natural habitat including the coastal areas of the southern half of the continent i.e . Western Australia, South Australia, New South Wales, Victoria, Tasmania and southern Queensland. The overall objective was to determine the environmental range by visits to selected sites of Crassula helmsii over its geographic range.

Effects of water movement and aeration system on the survival and growth of hatchery bred sugpo (Penaeus monodon Fabricius) in earthen nursery ponds

An experiment was conducted to determine the effects of water movement and airlift aeration on the survival and growth of P. monodon fry reared from P sub(4)P sub(5) to P sub(32)P sub(33) in earthen brackishwater ponds. The high survival rates obtained justify the need for aeration when using the earliest stages of fry (P sub(4)P sub(5)) at higher stocking densities. For older stages regardless of source and at lower stocking densities, nursery operations based on traditional methods could also achieve better survival rates.