Environmental Engineering Reference
In-Depth Information
microelectronics, water filtration, food production, clothing, and food packaging),
studies have shown that nanomaterials may have a greater reactivity and toxicity than
larger particles, and may accumulate in tissues, affecting human and organism health,
likely having undesirable and environmentally harmful
interactions with biological
systems (
Nel et al. 2006; Arora et al. 2012
).
New environmental contaminants and their anticipated widespread production, use,
and disposal will likely cause novel environmental hazards with unknown consequences
on human health, organisms, and ecosystem structure and function. Accounting for
unanticipated environmental effects caused by newly created substances and compounds
will continue in the foreseeable future. Thus, balancing the concern of the impact of new
technology on ecosystems without hindering innovation or development will certainly
provetobeachallenge.
Challenges Associated with Global Change
Global change (planetary-scale changes in Earth's system, such as climate change,
urbanization, land-use change, loss of diversity, etc.) is already affecting ecosystems,
and these effects are predicted to increase in the coming decades. Uncertainties related
to global change will surely be an important driver of ecosystem science in the twenty-
first century. However, it is not easy to comprehend the mechanisms underlying rapid
global change, and a substantial amount of research is still needed to understand pro-
cesses affected by changing environmental conditions at different spatial and temporal
scales.
One of the fundamental questions for the coming years will be to understand whether
ecosystems will be resilient to pressures of anthropogenic global change, and which
characteristics of ecosystems will promote resilience. Ecosystem responses to multiple
aspects of anthropogenic change will not be uniform within communities or across land-
scapes, and may be surprising when effects are not additive or synergistic (
Folke et al.
2004
). Topics ripe for investigation as potential stabilizing processes include plant
phenotypic plasticity, reduced mortality due to release from competition, and enhanced
mutualistic relationships under postdisturbance conditions. Ecosystem scientists will
need to consider connectivity between protectedareasandlandscapesthatareincreas-
ingly modified by human activities, including urban areas (
Pickett et al. 2004
).
Elucidating and managing for ecosystem resilience in the face of global change across
spatial and temporal scales will be a true test of ecosystem science.
Another intriguing unknown is the role of biotic feedbacks in global change.
For example, under global warming, marine biota could increase the release of dimethyl-
sulfide, resulting in long-lasting clouds, which may mitigate the effects of climate change
by increasing the global albedo (
Halloran et al. 2010
). However, other studies suggest that
higher temperatures will stratify the ocean, decreasing the supply of nutrients to phyto-
plankton, and therefore decrease dimethylsulfide production (
Cox et al. 2000
). Similarly,
higher atmospheric CO
2
concentrations can enhance carbon sequestration by forests,
slowing down the accumulation of CO
2
in the atmosphere; but higher atmospheric CO
2
concentrations may also increase the release of CH
4
and N
2
O(gaseswithstrong
