The influence of the ocean on the chemistry of precipitation in Nova Scotia*

Abstract

Between the fall of 1977 and December 1980, over 800 samples of precipitation were collected at 9 rural locations across Nova Scotia. Average pH was 4.61, and an average conductivity of 25 µS cm -1 confirmed the low ionic strength of rain and snow. Of all ions, chloride was the most abundant at 76 µeq L -1 (2.7 mg L -1 ). Oceanic origins were perceived as the source for chloride as well as for Na, Mg, 51 % of K, 21% of Ca, and 21% of SO 4 , and the sea collectively accounted for 66% of all ions inNova Scotian precipitation. In contrast, the dominating ions in New York, New Hampshire, Ontario and Norway were H + and SO 4 . In Nova Scotia, chloride concentrations in rain (mg L -1 ) are a function of distance D (km) from the coast and may be described by the equation Cl [mg L -1 ] = 4.5D -0.42 . It indicates that Cl concentrations are reduced by about 50% within 0.5 km of the coast, and 80% within 5 km. The continental North American chloride data examined are also consistent with the relationship. The shape of the chloride curve is similar to curves others have developed from rain and lake water chemistry observations in Holland and the United Kingdom, although those, and other European data, indicate that the marine influence is less pronounced in northeastern North America. The marine influence of precipitation chemistry on Nova Scotia has a maximum seasonal amplitude during the winter. RÉSUMÉ On a collecté, de l'automne 1977 à décembre 1980, plus de 800 échantillons de précipitation à 9 sites ruraux de Nouvelle-Écosse. Un pH moyen de 4,61 et une conductibilité moyenne de 25 µS cm -1 indiquent la faible teneur ionique de la pluie et de la neige. De tous les ions, le chlorure est le plus répandu, 76 µeq L -1 (2,7 mg L -1 ). On a constaté que le chlorure ainsi que le Na, le Mg, 51 % du K, 21 % du Ca et 21 % du SO 4 provenaient de source océanique et que collectivement avec l'océan ils étaient responsables de 66 % de tous les ions dans les précipitations de la province. Par contre, dans les états de New York et du New Hampshire, ainsi qu'en Ontario et en Norvège, les ions dominants étaient H + et SO 4 . En Nouvelle-Écosse, les concentrations de chlorure dans la pluie (mg L -1 ) sont fonction de *This paper is based on a presentation made at the Canadian Hydrology la distance des côtes D (km) et peuvent être décrites par l'équation Cl = 4,5D -0.42 qui indique que les concentrations de Cl sont réduites d'environ 50 % à moins de 0,5 km des côtes et de 80 % à moins de 5 km. Les données sur le chlorure, à l'échelle du continent nord-américain, font état du même rapport. La courbe du chlorure est semblable aux courbes développées par autres pour la pluie et les observations de la chimie des eaux lacustres en Hollande et au Royaume-Uni, bien que celles-ci et d'autres données européennes montrent que l'influence océanique est moins prononcée sur le nord-est de l'Amérique du Nord L'influence océanique de la chimie des précipitations sur la Nouvelle-Ecosse a une amplitude maximale saisonnière durant l'hiver.

Using sulfur stable isotopes to assess mercury bioaccumulation and biomagnification in temperate lake food webs

“…In fact, fish d 34 S values from our temperate systems were higher and more consistent with values from estuarine and marine fishes [26,28] than values in freshwater ecosystems in other parts of North America [12,14,25,27,44,45,47]. Although the lakes are considered to be in the "interior" of southwestern Nova Scotia, Kejimkujik receives relatively high mean annual precipitation (1330 mm [48]), no point of mainland Nova Scotia is farther than 55 km from a coastline, and marine aerosols influence the chemistry of all surface waters [49]. Although the lakes are considered to be in the "interior" of southwestern Nova Scotia, Kejimkujik receives relatively high mean annual precipitation (1330 mm [48]), no point of mainland Nova Scotia is farther than 55 km from a coastline, and marine aerosols influence the chemistry of all surface waters [49].…”

“…In the present study, the similarity of δ 34 S composition in aquatic ecosystems in this region to estimates from marine systems may be related to their proximity to the coast. Although the lakes are considered to be in the “interior” of southwestern Nova Scotia, Kejimkujik receives relatively high mean annual precipitation (1330 mm ), no point of mainland Nova Scotia is farther than 55 km from a coastline, and marine aerosols influence the chemistry of all surface waters . The present results also suggest that there is not always a clear threshold δ 34 S value that can distinguish between marine and freshwater S sources.…”