An Evaluation of 20 Year Changes in Chemistry in the EPA Easter Lake Survey, A Statistical Population of Lakes in the Northeastern U.S.
Notice bibliographique
Résumé
In 1984, the U.S. Environmental Protection Agency conducted the Eastern Lake Survey (ELS-I) to assess the overall status of the eastern U.S. lake population, with particular attention to the relationship between acidic deposition and ANC. In 1986, a subset of the ELS-I lakes consisting of 145 lakes in the northeastern U.S. was re-sampled during ELS- 11. In 2004, we re-sampled the ELS-I1 lakes approximately on the 20th anniversary of their original sampling. The data produced by the two samplings allow for assessments of biologically relevant chemical changes that may reflect reductions in acidic deposition due to regulations in both the U.S. and Canada. Over 90% of the ELS-I1 lakes decreased in SO4 from an average of 1 10 peq/L in 1984 to 86 peq/L in 2004. Of particular interest were changes in base cation concentrations [Ca+Mg] that supply ANC to surface waters. Change in [Ca+Mg] corresponded to lake C1 concentration, a reflection of ion exchange due to anthropogenic sources of salt, such as road salt. Approximately half the ELS-I1 lakes were unaffected by anthropogenic salt. ELS-I1 lakes affected by anthropogenic salt were defined by lake [Cl] greater than 4 times [Cl] of precipitation. Over 70% of the lakes not affected by salt experienced a decrease in [Ca+Mg] with an average change of -6.9 yeq/L over 20 years. Eighty-five % of salt-affected lakes increased in [Ca+Mg], with an average increase of +62 yeq1L. ANC increased from an average of 86 peq/L in 1984 to 102 peq/L in 2004. Nearly 80% of the lakes in the low ANC lakes (ANC < 25 yeqlL) experienced increases in EqpH from an average of 5.9 in 1984 to 6.2 in 2004. Approximately 90% of the population had decreases in total A1 with AlUC class I experiencing the greatest average change of -74 pg/L over 20 years. However, samples of total A1 were not filtered in 1984 while they were filtered in 2004 which may have resulted in an overestimation of decrease in total Al. DOC increased significantly with an average increase from 4.1mglL in 1984 to 5.6 mg/L in 2004. Reductions in S emissions have correlated with increased ANC and reduced A1 concentrations in the most acid sensitive surface waters. Reduced ANC and A1 are important indicators of improvement in biologically-relevant chemistry in northeastern U.S. lakes. However, decreases in base cation concentrations, particularly in low ANC systems unaffected by anthropogenic salt, slowed recovery from acidic deposition in some regions. Anthropogenic sources of salt throughout much of the northeastern U.S. complicated assessments of changes in lake chemistry, particularly by increasing [Ca+Mg]. While many lakes in the Adirondack region and in Maine were unaffected by anthropogenic sources of salt, there were no lakes in the statistical population from southern New England that were unaffected by anthropogenic salt. These data suggest that current models for selecting statistical lake populations are not appropriate and underscore the importance of site selection for drawing conclusions regarding the effects of deposition changes on lake chemistry.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,003 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».