Acidification of the HUMEX lake; effects on epilimnetic pools and fluxes of carbon

Journal Article · Wed Jan 01 00:00:00 EST 1992 · Environment International; (United States)

DOI:https://doi.org/10.1016/0160-4120(92)90032-Y· OSTI ID:7064246

Hessen, D O ^[1]

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1. Norwegian Inst. for Water Research, Oslo (Norway)

The paper presents data on carbon budgets during the first year of acidification of one half of humic lake Skjervatjern. Dissolved organic carbon (DOC), mainly allochthonous humus, ranged from 2 to 12 mg C L[sup [minus]1], with an average of 6 to 7 mg C for both the acidified and the reference basin. The minimum values occurred during winter when ground temperature fell below zero. Average dissolved inorganic carbon (DIC) was near 500 [mu]g C L[sup [minus]1] in the surface layers, but increased to more than 2 mg close to the bottom. Epilimnetic particulate organic carbon (POC) was also close to 500 [mu]g C L[sup [minus]1], of which more than 3/4 was detritus, while bacteria, phyto-, and macrozooplankton made up approximately 100, 50, and 20-40 [mu]g C L[sup [minus]1], respectively. Major flows were sedimentation, respiration, and discharge. Acidification gave no clearcut effects on the major pools and fluxes of carbon, which were mainly governed by climatic and hydrological events. There were, however, pronounced differences in biotic pools and biologically mediated carbon fluxes, with more unstable conditions in the acidified basin. Primary production and phytoplankton biomass increased in the acidified basin relative to the control. Zooplankton biomass had a strong midsummer peak, followed by a sudden collapse of the dominant species, Holopedium gibberum, in the acidified part. As a consequence, zooplankton community grazing also dropped. Grazing did, however, not exert an efficient control with phytoplankton biomass. Preliminary data indicated decreased respiration and increased sedimentation in the acidified part. A closer follow-up of these processes will be performed during the two upcoming years in order to separate transitional and more permanent changes in carbon metabolism. 19 refs., 6 figs., 1 tab.

• OSTI ID: 7064246
• Journal Information: Environment International; (United States), Vol. 18:6; ISSN 0160-4120
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
59 BASIC BIOLOGICAL SCIENCES
ACID RAIN
BIOLOGICAL EFFECTS
ENVIRONMENTAL EFFECTS
ORGANIC COMPOUNDS
WATER CHEMISTRY
SURFACE WATERS
ACIDIFICATION
CARBON CYCLE
BACTERIA
EXPERIMENTAL DATA
PHYTOPLANKTON
SEDIMENTATION
ZOOPLANKTON
AQUATIC ORGANISMS
ATMOSPHERIC PRECIPITATIONS
CHEMISTRY
DATA
INFORMATION
MICROORGANISMS
NUMERICAL DATA
PLANKTON
PLANTS
RAIN
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
550700 - Microbiology