Impacts of pollution on coastal and marine ecosystems including coastal and marine fisheries and approach for management: a review and synthesis

The history of aquatic environmental pollution goes back to the very beginning of the history of human civilization. However, aquatic pollution did not receive much attention until a threshold level was reached with adverse consequences on the ecosystems and organisms. Aquatic pollution has become a global concern, but even so, most developing nations are still producing huge pollution loads and the trends are expected to increase. Knowledge of the pollution sources and impacts on ecosystems is important not only for a better understanding on the ecosystem responses to pollutants but also to formulate prevention measures. Many of the sources of aquatic pollutions are generally well known and huge effort has been devoted to the issue. However, new concepts and ideas on environmental pollution are emerging (e.g., biological pollution) with a corresponding need for an update of the knowledge. The present paper attempts to provide an easy-to-follow depiction on the various forms of aquatic pollutions and their impacts on the ecosystem and organisms.     

Energetics and Dynamics of an Impulsive Flare on March 10, 2001

We present Hα observations from ARIES (Nainital) of a compact and impulsive solar flare that occurred on March 10, 2001 and which was associated with a CME. We have also analyzed HXT, SXT/Yohkoh observations as well as radio observations from the Nobeyama Radio Observatory to derive the energetics and dynamics of this impulsive flare. We coalign the Hα, SXR, HXR, MW, and magnetogram images within the instrumental spatial-resolution limit. We detect a single HXR source in this flare, which is found spatially associated with one of the Hα bright kernels. The unusual feature of HXR and Hα sources, observed for the first time, is the rotation during the impulsive phase in a clockwise direction. We propose that the rotation may be due to asymmetric progress of the magnetic reconnection site or may be due to the change of the peak point of the electric field. In MW emission we found two sources. The main source is at the main flare site and another is in the southwest direction. It appears that the remote source is formed by the impact of accelerated energetic electrons from the main flare site. From the spatial correlation of multiwavelength images of the different sources, we conclude that this flare has a three-legged structure.     

Development of a numerical model for nitrates in groundwater in the reservoir area of the Komesu subsurface dam, Okinawa, Japan

A numerical model consisting of simplified equations was developed to simulate nitrate concentrations in groundwater in a reservoir area of a subsurface dam in a Quaternary limestone region. The model was composed of a water balance sub-model and a nitrogen balance sub-model; the water balance sub-model was built from tank models which can express the quick dilution near caves and the effect of dam construction; and the nitrogen balance sub-model was made to represent changes in nitrogen forms and movement of nitrogen in the soil and aquifer zones. The model was calibrated and verified by observed data before and after the dam construction and then applied to a predictive simulation under a simple assumption that rainfall descends gradually. The model seemed applicable to long-term prediction of changes in NO₃-N in the reservoir area.     

Characteristics of Porphyry Cu Mineralization at Waisoi (Namosi District), Viti Levu, Fiji

The porphyry Cu deposits at Waisoi in Namosi district, Viti Levu are separated into two deposits: the Waisoi East deposit and the Waisoi West deposit. In the Waisoi East deposit, quartz porphyry is exposed and in the Waisoi West deposit, diorite porphyry is sporadically exposed in addition to a small body of quartz porphyry. The mineralization in the Waisoi East deposit is characterized by the bornite–chalcopyrite–pyrite assemblage associated with traces of molybdenite and native gold. Polyphase fluid inclusions in stockwork quartz veinlets show homogenization temperatures ranging from 210 to >500°C. The high‐grade Cu mineralization in the Waisoi West deposit is characterized by the bornite–chalcopyrite–pyrite assemblage accompanied with sheeted and stockwork quartz veinlets. Polyphase fluid inclusions occasionally containing hematite flakes in quartz veinlets in the center of the Waisoi West deposit homogenize at temperatures ranging from 450°C to >500°C. However, fluid inclusions in stockwork quartz veinlets in the periphery, homogenize at lower temperatures around 210°C. Both in the Waisoi East and Waisoi West deposits, primary bornite–chalcopyrite–pyrite assemblage in the high Cu‐grade zone was deposited at the upper stability limit of chalcopyrite with respect to sulfur fugacity. Thus, the principal Cu mineralization at the Waisoi deposits occurred at a relatively high sulfur fugacity, that is, in a high‐sulfidation environment.     

Compensatory response of the unicellular-calcifying alga <Emphasis Type="Italic">Emiliania huxleyi</Emphasis> (Coccolithophoridales,Haptophyta) to ocean acidification

Ocean acidification damages calcareous organisms, such as calcifying algae, foraminifera, corals, and shells. In this study, we made a device equipped with a Clark-type oxygen electrode and a pH-stat to examine how the most abundant calcifying phytoplankton, the coccolithophorid Emiliania huxleyi, responded to acidification and alkalization of the seawater medium. When E. huxleyi was incubated at pH 8.2, close to oceanic pH, the medium was alkalized during photosynthesis, and the alkalization rate [determined as μmol HCl added (mg Chl)⁻¹ h⁻¹] was identical to the activity of photosynthesis [determined as μmol O₂ evolved (mg Chl)⁻¹ h⁻¹]. When pH was maintained at 7.2 by the pH-stat, alkalization activity was stimulated and exceeded photosynthetic activity, resulting in an increase in the ratio of alkalization to photosynthesis (Alk/PS). On the other hand, no alkalization and photosynthesis were observed at pH 9.2. In contrast, acidification of seawater was observed in the dark because of the release of respiratory CO₂ from cells at pH 8.2–9.2, but not at pH 7.2. When orthophosphate was rapidly depleted within a day in the batch culture, intracellular calcification gradually increased, and both photosynthesis and alkalization decreased gradually. During the period the Alk/PS ratio also decreased gradually. These results indicate that E. huxleyi possesses an ability to compensate for the acidification of seawater when photosynthesis is more actively driven than respiration. These results suggest that the E. huxleyi cells may not be severely damaged by oceanic acidification during photosynthesis because of their homeostatic function to avoid negative effects on cellular activity. Finally, we concluded that E. huxleyi cells possess a buffering ability to reduce acidification effects when photosynthesis is actively driven.