Opinion: The importance of long term data on ecosystem function
This post is actually quite appropriate to the SERC Solar Radiation Laboratory (connected to the Photobiology Lab where I work), in which long term data on solar UV is collected...
Shifting Baselines
Why, you might ask, should the public care? As a member of a civilization that runs at such a fast pace and large scale, is is only through information collected a while back that we have a baseline with which to compare the current state. We need to know what bays and other ecological systems were like in the past to know how they are changing. The problem with just taking a baseline now is that it could have already shifted from human influence. This phenomenon is called 'shifting baselines,' and the classic example is of the change in size and number in cod population.
"[Shifting baseline syndrome] has arisen because each generation of fisheries scientists accepts as a baseline the stock size and species composition that occurred at the beginning of their careers, and uses this to evaluate changes. When the next generation starts its career, the stocks have further declined, but it is the stocks at that time that serve as a new baseline. The result obviously is a gradual shift of baseline, a gradual accommodation of the creeping disappearance of resource species, and inappropriate reference points for evaluating economic losses resulting from overfishing, or for identifying targets for rehabilitation measures."
Nutrients in Bays: A big problem in the Chesapeake but not in the San Fransisco Bay
These particular scientists have found strikingly different consequences for high nutrient loads in bays in two different parts of the country. In San Fransisco, shellfish do an amazing job of filtering phytoplankton out of the water, and nutrient levels are actually higher than in the Chesapeake. Over the last 10-20 years, there has been a shift in which animals are dominant, BUT this can be attributed to a natural oceanographic phenomenon (Pacific decadal oscillation). In the Chesapeake, however, nutrients from farming, and other human activities, leak out into the Chesapeake and cause low oxygen 'dead zones' that can kill fish and other organisms.
In the Chesapeake there are fewer shellfish these days than 100 years ago (I heard over 90% loss?), so likely there is now a lowered capacity to deal with high nutrient and resulting phytoplankton loads. Also, the West Coast experiences upwellings of cold nutrient-rich (and low oxygen) deeper ocean water from time to time, so maybe the San Fransisco Bay has had to adapt to this kind of situation regardless of human impact.
Anyway, the point of the story is that management of factors such as high nutrient loads cannot be done using blanket generalizations. High nutrient amounts in the Chesapeake are a problem even though they are lower than levels experienced in the San Fransisco Bay.
What can you do?
These scientists urged us after the lecture to contact our politicians. One of the scientists was involved in a zonation hearings committee.
See the South River Federation Website to volunteer and help out with work in the Chesapeake. They do oyster reef restoration and other projects...
