Focusing on the Large Marine Ecosystems (LMEs) of the world, this course will introduce the concept and practice of ecosystem-based management. LMEs occupy areas of coastal ocean at least 200 000 km² or greater in size. These coastal waters produce 12.6 trillion USD in ecosystem goods and services annually and are vitally important for billions of people around the globe. Because LMEs are bounded by ocean features and are globally linked, management of human activities needs to occur in an integrated fashion across political boundaries and economic sectors (e.g. fishing, shipping, energy, tourism, and mining.) This represents a new type of management approached - shifting from single sector-based to multi-sector assessment and management within the spatial domain of the world's 66 Large Marine Ecosystems. There is global high-level support for this new approach and in this course, we will introduce the concepts and tools for assessing and managing LMEs. Together, leaders and experts in a global movement to recover and sustain the goods and services of LMEs will introduce you to the mechanisms used for assessment (Transboundary Diagnostic Analysis), planning and implementation (Strategic Action Programme). Based on recent activities in implementation and practice of the LME approach in 22 projects around the globe, we will showcase examples of effective management at this scale, and highlight the challenges and issues. By the end of the online course, we hope you will be able to actively use this knowledge to advance sustainable development of the world’s oceans. The course was created with the support and input of: the Global Environment Facility (GEF), the United Nations Development Program (UNDP), the National Oceanic and Atmospheric Administration (NOAA), UNESCO-IOC and IW:LEARN.
Pollution and ecosystem health
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From the course by University of Cape Town
Large Marine Ecosystems: Assessment and Management
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From the lesson
The Three Natural Science Modules
In this week, we deal with the three natural science modules within the five module approach.
Meet the Instructors
Coleen MoloneyAssociate Professor
Marine Research Institute
Of the three natural science modules in the large marine ecosystem approach,
the one on pollution and ecosystem health is the broadest in scope,
because it covers all the factors that affect the health of a marine ecosystem.
A healthy ecosystem is able to maintain
its physical and biological structure within normal bounds.
It's resilient to natural and unnatural perturbations
and it functions within acceptable limits
so it's able to continuously provide ecosystem services.
In contrast, an unhealthy ecosystem has experienced pressures that have
changed its physical structure or its chemistry or its living communities
so the ecosystem no longer provides the ecosystem services that it used to.
There are many pressures that can change the health of an ecosystem.
But this module focuses mainly on aspects of marine pollution and changes in
environmental chemistry because some of
the other pressures are covered in the other two natural science modules.
As examples of important ecosystem health issues,
I will talk briefly here about coastal eutrophication
and I invite you to view two video lectures that cover
the emerging issues of ocean acidification and marine plastic pollution.
Coastal eutrophication is a widespread issue affecting ecosystem health.
It occurs when nutrients like nitrogen and
phosphorus enter the coastal ocean in excessive amounts,
as runoff from land-based sources.
The nutrients active fertilizers causing rapid growth of
marine phytoplankton and outstripping the capacity of grazers to keep up,
eventually leading to high biomass harmful algal blooms.
Once the nutrients are depleted in these blooms,
there is mass mortality of the phytoplankton,
which leads to a build up of bacteria which decompose the phytoplankton,
but also use up oxygen in the process,
and this causes low-oxygen or no-oxygen dead zones in the coastal ocean.
These conditions cause mass mortalities of
other marine organisms like fish and shellfish.
They facilitate the emergence of marine pathogens and they
favor the explosive growth of species introduced from other regions.
Computer simulations that have projected the effects of
human-caused coastal eutrophication a few decades into
the future placed five large marine ecosystems at high risk.
These are the large marine ecosystems for the Gulf of Mexico,
the North Brazil Shelf,
the Bay of Bengal,
the East China Sea,
and the South China Sea.
What these high risk large marine ecosystems
have in common is the fact that they are linked to
extensive watersheds which receive nutrient loads from
intensive application of agricultural fertilizer and livestock production.
Coastal eutrophication can be addressed by increasing the efficiency
of nutrient use in crop production and by removing nutrients,
like nitrogen and phosphorus,
from sewage and waste water systems.
To monitor pollution and ecosystem health in the ocean,
it's possible to use indicators.
For pollution, these can be derived from the pathobiological examination of fish,
also through estuarine and nearshore monitoring of contaminants in the water column,
in the sediments, and in selective groups of organisms like mussels.
For some pollutants like heavy metals, bioaccumulation can occur
when the contaminants are transferred up a food chain without excretion,
thus becoming more and more concentrated at each trophic level.
These kinds of pollution effects can be assessed by examining
critical life history stages and by examining particular species,
like top predators, for indications of exposure to the pollutants.
Some of the indications of pollution include
impaired reproductive capacity and growth and disease of organs.
For measuring ecosystem health,
the Ocean Health Index was developed by
a group of researchers at the University of California, Santa Barbara.
It measures progress towards achieving 10 goals for healthy oceans.
And the scores for these can also be combined into a single aggregated value.
When the Ocean Health Index was applied to large marine ecosystems,
it was found that low scoring ecosystems generally were found in tropical areas,
whereas high scoring ecosystems generally occurred at more temperate latitudes.
All these measures and indicators not only help
improve understanding of what influences the state of an ecosystem,
but they also allow the assessment of ecosystem state
to be communicated effectively so that actions can be taken.
Many high profile environmental issues
fall under the pollution and ecosystem health module.
For many of these issues,
they are often obvious solutions,
and the fact that these aren't being implemented points
very strongly to the need to take into
account the issues we will be covering
next week in the modules relating to the human dimensions.
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