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FROM THE FOREST TO THE SEA AND BACK AGAIN: MARINE INPUTS AND TERRESTRIAL BIOGEOCHEMISTRY IN THE PACIFIC NORTHWEST
Citation:
COMPTON, J. E. FROM THE FOREST TO THE SEA AND BACK AGAIN: MARINE INPUTS AND TERRESTRIAL BIOGEOCHEMISTRY IN THE PACIFIC NORTHWEST. Presented at Western Society of Naturalists Annual Meeting, Monterey, CA, November 17 - 20, 2005.
Impact/Purpose:
To study the influence of materials derived from the ocean on terrestrial ecosystem processes
Description:
Most models of watershed biogeochemistry include the movement of materials from land to rivers and eventually the ocean. Few conceptual views, however, acknowledge the influence of materials derived from the ocean on terrestrial ecosystem processes. Based on spatial patterns of stream chemistry in the Oregon Coast Range, it is possible that deposition of marine aerosols stimulates nitrate leaching from coastal forest soils. This work also considers the flux of elements from the ocean to the land via current and historic salmon migration. This study induced nitrate leaching by adding salt solutions in lab experiments using root-free soils. Salt deposition may influence nitrate dynamics through a number of mechanisms, including abiotic (direct exchange of chloride for nitrate), biotic (inhibition of microbial activity) and coupled abiotic-biotic effects (exchange of sodium for ammonium, then nitrification). Direct exchange of chloride for nitrate did not occur, but strong salt solutions did displace ammonium from the exchanger. In field experiments, addition of dilute sodium chloride solutions depressed soil respiration, indicating a biotic response at salt concentrations comparable to coastal deposition values. Lab salt additions also decreased the leaching of dissolved organic carbon, which has implications for the cycling of nitrogen and net nitrate production. Our findings of an interaction between marine aerosol inputs and soil processes represent a new perspective on nutrient dynamics in near coastal ecosystems.