A long-term record of human impacts on an urban ecosystem in the sediments of Töölönlahti Bay in Helsinki, Finland

1997 ◽  
Vol 24 (4) ◽  
pp. 326-337 ◽  
Author(s):  
MATTI TIKKANEN ◽  
ATTE KORHOLA ◽  
HEIKKI SEPPÄ ◽  
JUHANI VIRKANEN
Keyword(s):  
Human Impacts ◽  
Coniferous Forest ◽  
Urban Ecosystem ◽  
Ecological Impacts ◽  
Pollen Record ◽  
Diatom Species ◽  
Long Term Effects ◽  
Land Uplift ◽  
Forest Clearance

Ecological impacts of urbanization are receiving increasing scientific attention, yet few data sets permit long-term effects on terrestrial and aquatic ecosystems to be assessed. Töölönlahti Bay, in the centre of Helsinki, Finland, provided on opportunity to characterize recent human impacts especially by means of chemical and biostratigraphical analyses of a sediment core. Periods of coniferous forest, forest clearance, urbanization and the development of parks, can be distinguished in the pollen record of the core. Palynological diversity was highest before the forest clearance at the turn of the century. The character of the sediment and the water have changed substantially in response to rapid population growth, the construction of sewage systems and building within the catchment of the bay. This is reflected in marked increases in organic matter, phosphorus and heavy metal (Cd, Cu, Ni, Zn and Pb) concentrations between 1890 and 1960, accompanied by a rapid increase in diatom species indicative of eutrophication and a decline in diatom species diversity.Since the cessation of waste-water disposal in the 1960s, concentrations of a number of pollutants have declined and water quality has gradually improved, but conditions are still affected by internal and atmospheric loadings. As a consequence of land uplift (2 mm per year) and the rapid sedimentation rate (6 mm per year), the volume of the bay is decreasing. Within 200 years, the shallow bay, which is skirted by extensive parks and famous cultural buildings such as the Finlandia and the Opera Houses, will fill with sediment unless it is dredged.

scholarly journals Long-term effects of timber harvesting on hemicellulolytic microbial populations in coniferous forest soils

2015 ◽  
Vol 10 (2) ◽  
pp. 363-375 ◽  
Author(s):  
Hilary T C Leung ◽  
Kendra R Maas ◽  
Roland C Wilhelm ◽  
William W Mohn
Keyword(s):  
Forest Soils ◽  
Coniferous Forest ◽  
Timber Harvesting ◽  
Microbial Populations ◽  
Long Term Effects

Assessment of recent environmental changes in New Brunswick (Canada) lakes based on paleolimnological shifts in diatom species assemblages

2006 ◽  
Vol 84 (1) ◽  
pp. 151-163 ◽  
Author(s):  
M. Anne Harris ◽  
Brian F. Cumming ◽  
John P. Smol
Keyword(s):  
Climate Change ◽  
New Brunswick ◽  
Environmental Changes ◽  
Environmental Data ◽  
Species Assemblages ◽  
Past Century ◽  
Diatom Species ◽  
Long Term Effects ◽  
Recent Climate

New Brunswick lakes are subjected to multiple environmental stressors, such as atmospheric acid deposition and climate change. In the absence of long-term environmental data, the impacts of these stressors are not well understood. Long-term effects of environmental change on diatom species assemblages were assessed in the sediments of 16 New Brunswick lakes using paleolimnological approaches. A regional trend of increasing Cyclotella stelligera Cleve & Gunrow and decreasing Aulacoseira species complex was recorded in most lakes. Detailed paleolimnological analyses of Wolfe, Cundy, and West Long lakes revealed varying degrees of species change, with assemblage shifts beginning ca. 1900 CE (common era). These species trends are not consistent with acidification. However, linear regression of mean July temperature with time for two New Brunswick historical instrumental temperature records revealed statistically significant warming over the past century. The shift from heavily silicified tychoplanktonic Aulacoseira species to small planktonic diatom species, such as C. stelligera, is consistent with paleolimnological inferences of warming trends recorded in several other lake regions of the Northern Hemisphere. These assemblage shifts are likely due to recent climate change and may be mediated by reduced ice cover and (or) increased thermal stability (decreased lake mixing) during the open water period.

scholarly journals Plant responses to volcanically elevated CO<sub>2</sub> in two Costa Rican forests

2019 ◽  
Vol 16 (6) ◽  
pp. 1343-1360 ◽  
Author(s):  
Robert R. Bogue ◽  
Florian M. Schwandner ◽  
Joshua B. Fisher ◽  
Ryan Pavlick ◽  
Troy S. Magney ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Chlorophyll Concentration ◽  
Carbon Isotopic Composition ◽  
Tropical Trees ◽  
Ecological Impacts ◽  
Atmospheric Co2 ◽  
Natural Experiments ◽  
Long Term Effects ◽  
Active Volcanoes

Abstract. We explore the use of active volcanoes to determine the short- and long-term effects of elevated CO2 on tropical trees. Active volcanoes continuously but variably emit CO2 through diffuse emissions on their flanks, exposing the overlying ecosystems to elevated levels of atmospheric CO2. We found tight correlations (r2=0.86 and r2=0.74) between wood stable carbon isotopic composition and co-located volcanogenic CO2 emissions for two of three investigated species (Oreopanax xalapensis and Buddleja nitida), which documents the long-term photosynthetic incorporation of isotopically heavy volcanogenic carbon into wood biomass. Measurements of leaf fluorescence and chlorophyll concentration suggest that volcanic CO2 also has measurable short-term functional impacts on select species of tropical trees. Our findings indicate significant potential for future studies to utilize ecosystems located on active volcanoes as natural experiments to examine the ecological impacts of elevated atmospheric CO2 in the tropics and elsewhere. Results also point the way toward a possible future utilization of ecosystems exposed to volcanically elevated CO2 to detect changes in deep volcanic degassing by using selected species of trees as sensors.

Human impacts on soft-sediment systems—trawling and fisheries

2009 ◽  
Author(s):  
John S. Gray ◽  
Michael Elliott
Keyword(s):  
World War Ii ◽  
Human Impacts ◽  
Otter Trawl ◽  
Status Report ◽  
Complex Nature ◽  
Long Term Effects ◽  
Ecosystem Effects ◽  
The 1960S ◽  
The Impact

Given the discussion above regarding natural changes in the marine benthos, we should now consider the human-mediated (anthropogenic) changes and the response of benthic systems to human impacts. From the 1960s to the 1980s the general opinion seemed to be that pollution (considered in the next chapter) was the most important marine problem, but we now realize that habitat change and habitat loss are of greater concern: see, for example, the Quality Status Report 2000 (OSPAR 2000). One of the greatest effects on the integrity of the seabed and hence its biota is now known to be caused by bed trawling. This has now generated an enormous literature, and the reader is directed to Daans and Eleftheriou (2000) and Hollingworth (2000) for more details. We can take this information and summarize the overall ecosystem effects of fisheries in detailed flow diagrams (referred to as ´horrendograms´!) to show the interlinked and complex nature of the impact—the effects trawling are included here, but see also those in McLusky and Elliott (2004) (e.g. Fig. 8.1). Historically, the effects of trawling on benthos caused concern as early as 1376 when a petition was made to the English parliament by fishermen concerned over the damage done to the seabed and fisheries by bottom trawling (De Groot 1984). This was despite the gear used by sailing vessels in those days being relatively light and towed at slow speeds and in shallow water only. When steam trawlers were developed in the early 1900s, everything changed. The weight and size of trawls increased and use of tickler chains (mounted on the bottom rope to disturb bottom-living fish upwards and into the trawl net) were of great concern, although studies done in the 1970s to allay the fears of fishermen did not find long-term effects on macrobenthos (Jones 1992). At the end of World War II the otter trawl was developed and its use became widespread. This and the beam trawl (see Fig. 8.4) were (and still are) the types of gear most widely used to fish the seabed.

scholarly journals Plant responses to volcanically-elevated CO<sub>2</sub> in two Costa Rican forests

2018 ◽  
Author(s):  
Robert R. Bogue ◽  
Florian M. Schwandner ◽  
Joshua B. Fisher ◽  
Ryan Pavlick ◽  
Troy S. Magney ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Chlorophyll Concentration ◽  
Carbon Isotopic Composition ◽  
Tropical Trees ◽  
Ecological Impacts ◽  
Atmospheric Co2 ◽  
Natural Experiments ◽  
Long Term Effects ◽  
Active Volcanoes

Abstract. We explore the use of active volcanoes to determine the short- and long-term effects of elevated CO2 on tropical trees. Active volcanoes continuously but variably emit CO2 through diffuse emissions on their flanks, exposing the overlying ecosystems to elevated levels of atmospheric CO2. We found tight correlations (r2 = 0.86 and r2 = 0.74) between wood stable carbon isotopic composition and co-located volcanogenic CO2 emissions for two species, which documents the long-term photosynthetic incorporation of isotopically heavy volcanogenic carbon into wood biomass. Measurements of leaf fluorescence and chlorophyll concentration suggest that volcanic CO2 also has measurable short-term functional impacts on select species of tropical trees. Our findings indicate significant potential for future studies to utilize ecosystems located on active volcanoes as natural experiments to examine the ecological impacts of elevated atmospheric CO2 in the tropics and elsewhere. Results also point the way toward a possible future utilization of ecosystems exposed to volcanically elevated CO2 to detect changes in deep volcanic degassing by using selected species of trees as sensors.

Long-term Consequences of Upstream Impoundment

1980 ◽  
Vol 7 (4) ◽  
pp. 325-332 ◽  
Author(s):  
Geoffrey E. Petts
Keyword(s):  
Human Impacts ◽  
Channel Morphology ◽  
Long Term Effects ◽  
Third Order ◽  
First Order ◽  
Channel Form ◽  
Sediment Loads ◽  
Flood Magnitude ◽  
Invertebrate Population

Since 1970 a large number of environmental problems have been identified as resulting from the long-term effects of human impacts. Consideration of human activity within the environment as three orders of impact, provides a basic framework for the appreciation and evaluation of long-term problems. Consequent upon dam construction, major changes of flood magnitude and frequency and of the quantity and calibre of sediment loads (first-order impacts), will induce the readjustment of channel morphology and ecology (second-order impacts). However, the macrophytic and macro-invertebrate population, for example, are also adjusted to channel morphology—particularly channel shape and substrate composition—so that further readjustments of the macrophyte and macro-invertebrate populations may be effected by changes of channel form (third-order impacts).

scholarly journals Economic Transformation of the Nicobar Islands Post-tsunami

2021 ◽  
Vol 4 (2) ◽  
pp. 119-147
Author(s):  
Shaina Sehgal ◽  
Suresh Babu
Keyword(s):  
Construction Materials ◽  
Economic Transformation ◽  
Ecological Impacts ◽  
Regional Economies ◽  
Long Term Effects ◽  
The Social ◽  
Trading Partners ◽  
Import And Export ◽  
Nicobar Islands

Natural disasters can have lasting impacts on regional economies. Island economies, in particular, have protracted recoveries from disasters due to their location, size, and economic dependence on trading partners. As imports and exports are especially explicit and discernible in ports, islands facilitate investigations on the long-term effects of disaster relief, reconstruction, and redevelopment on trade. In this paper, we examine the transformational impact of the 2004 Indian ocean earthquake and tsunami. We examine changes to physical imports and exports in the archipelago to reflect on the social, economic, and ecological impacts of the 2004 disaster and subsequent recovery. We analyse disaggregated physical import and export data for 2003–2017 from revenue ports in the Nicobar Islands in India along with data from field surveys and interviews conducted on the islands. We find that while the archipelago’s physical trade balance has been continuously growing since 2003, it increased at a higher rate after the disaster and thereafter stabilized to levels comparable to the pre-tsunami period. However, further analysis indicates that the nature and quantity of physical imports during this period, such as of fuel and construction materials, are unprecedented; and there are diverging trajectories of redevelopment within the archipelago...

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

Sign in / Sign up

Export Citation Format

Share Document