The LA Times has a piece about red tides and algae blooms, which are intensified by things like fertilizer runoff and high levels of organic waste. Bottom dredging, a popular and very damaging form of commercial fishing, can also create problems. The thing is, algae poisons can be extremely deadly, and so the effects of inhaling small amounts can include serious health risks for folks on the shoreline. Meanwhile, you can imagine what it does to marine life.
As you might guess, red tides are increasing in frequency since the 1970s. Sharply.
Patricia M. Glibert, a marine scientist at the University of Maryland, has done research indicating that the worldwide spread of paralytic shellfish poisoning closely tracks the expanding use of urea nitrogen fertilizer. She estimates that fertilizer use will rise 50% this decade "in parts of the world that are already saturated with nitrogen and frequently plagued by harmful blooms."
Cynthia Heil, a senior state scientist in Florida, sees the relationship more as pollution from agriculture intensifying or prolonging the outbreaks. After all, blooms also emanate far out at sea. Heil and a team of university scientists have published a study theorizing that iron-rich dust from Africa's Sahara Desert drifts across the Atlantic and triggers a natural process that stimulates harmful algae blooms off Florida's Gulf Coast. "The timing sure matches up with blooms," Heil said. "We know it has to contribute to enriching seawater with iron and nitrogen."
Who's right? Actualy, there no reason why both of them couldn't be correct. Fertilizer, man's impact in removing natural filters like wetlands, et. al. intensify some and/or cause some, natural cycles cause others. Result: more problems, more often, that are more severe.
Unlike global warming, this is an area of science where the links to human activity are testable, tight, consistent, and sizeable in relative scale. It's also an area where the time-lag between cause and effect is quite tight, and the cycles can reliably be affected by human choices.
As the effects gather, it may be time to rethink some of the choices that we're making. We can't end this problem entirely - but we can find ways to avoid feeding it.
Somebody needs to make up their freaking mind, because I've heard global warmers propose dumping massive amounts of iron dust into the oceans to stimulate algae growth, as a way of absorbing more CO2.
We obviously have a problem with irresponsible people who live on coastlines, exposing themselves to red slime, hurricanes, and melting polar ice caps. Find some high ground and haul your fat glutes up there!
...If La Palma goes, you'll be glad you did! (Explanation of the La Palma/ Cape Verde mega-tsunami possibility - think 150 foot waves along most of the eastern US seaboard, for no reason related to anything humans do.)
And I think we can safely rule out the iron dust plan as a good idea.
Patricia M. Glibert, a marine scientist at the University of Maryland, has done research indicating that the worldwide spread of paralytic shellfish poisoning closely tracks the expanding use of urea nitrogen fertilizer. She estimates that fertilizer use will rise 50% this decade "in parts of the world that are already saturated with nitrogen and frequently plagued by harmful blooms."
Joe, what are the alternatives to the use of urea nitrogen fertilizer? How effective are they? Are there mitigation strategies/techniques that would significantly reduce the flow of fertilizer residues into the sea? What impact would there be on agricultural productivity, and food cost, if we banned the use of urea nitrogen fertilizer?
Reducing the flow of organic wastes into both freshwater and sea water is something we can and should do. Ending bottom dredging as a commercial fishing practice is also something we can do. (It may substantially increase the cost of harvesting some shellfish but it won't have much impact on the overall cost of producing our food supply).
Thanks for posting about this. It’s definitely an issue to watch.
There are alternatives to the level of fertilizers currently used, which is extremely high, but the practice will not be going away by any means. The most obvious mitigation strategy is to foster healthy wetlands as part of the processing and cleanup chain, either near the source of the waste or at the end.
Note that organic farming may disdain chemical fertilizers, but problems like Pfisteria blooms from pig farm waste prove that natural fertilizers can work the same way.
The dilemmas will bite poorer countries hardest, as fertilizers are used to improve productivity and keep starvation at bay, while fostering wetlands could breed disease. On the other hand, destroying wetlands and using lots of fertilizer will bring serious health hazards and noticeable numbers of deaths to the highly-populated seacosts. Plus, if red tides et. al. become more frequent they'll put a serious crimp in seafood production, which is its own important source of calories and currency.
Breaking those dilemmas probably takes us into the realm of biotechnology via seed stocks engineered not to need so much fertilizer and support (currently not the incentive pattern), in addition to a rethink of some farming methods and subsidy structures. How big a rethink may depend in part on the relative importance and political power of seacost industries and dwellers versus agriculture... but in the end, they're all in the same interconnected boat if the country is anywhere close to the edge on food production.
As always, other options can be found if a problem is acknowledged. Could more mangrove swamps absorb some of the excess nutrients in more tropical areas, to the benefit of all without quite the same insect disease vector issues as a freshwater swamp? Don't know.
But once the problem is acknowledged, the effort of finding out, devising ways to improve the situation, and religning behavioural incentives can begin.
I'm going to wade into this one with both feet because not only do I make my living as a farmer, but I'm an agronomist and soil chemist by training.
Let's lay down some clear, technical baselines for this discussion.
a) The limiting nutrient in fresh water systems is phosphorus, and abundant supplies thereof will trigger algal blooms.
b) In salt water systems the limiting nutrient is nitrogen.
c) Nitrogen is nitrogen is nitrogen. It makes no significant difference to salt water systems if it comes out of a tank, a bag, or the arse end of a critter. It does make a difference to soil and crop, but that's a different discussion.
d) The salt water nitrogen problem is a direct result of leaching, run-off, and erosion, all of which reflect somewhat sloppy crop rotation and field management.
e) Common fertiliser sources of nitrogen are:
+ Anhydrous ammonia -- 82% N
+ Urea -- 46% N
+ Ammonium nitrate -- 34% N
+ Diammonium phosphate -- 18%N
f) Anhydrous is pretty rough on the soil and a lot of it may be lost to the air. Many farmers apply it in the fall (when they can work their ground) and double the application rate to cover leaching and runoff losses ... which are much worse in winter.
g) Urea is applied as granules, but if not covered almost immediately much of it will evaporate in to the air, and if it rains a lot more can be lost to run-off.
That's plenty for now. I'll step in later with several practical alternatives for effective nitrogen fertility without the negative environmental impact.
HINT: Much of my farm is planted to alfalfa.
Okay, not a lot of interest here. That's too bad as it's actually an important topic. As I hinted yesterday a lot of the solution lies in the realm of crop rotation, and in particular the use of soil-building legume sod crops, like alfalfa.
They fix nitrogen out of the air -- if I wanted to geek y'all out I could go into gruesome detail on the molybdenum-mediated nitrogenase reaction making it all possible -- and their roots bind the soil together.
The problem with "hay" is that not only is it not eligible for USDA Farm Program subsidies, but after any length of time it starts dequalifying your ground from those subsidies.
A co-dependent problem is that in many areas livestock are also produced in a highly concentrated setting, so their manure (instead of building the soil) becomes a run-off problem.
So there are basically two broad ways to address the nitrogen run-off problem:
a) Impose an intrusive and oppressive regulatory scheme to control nitrogen use on the farm.
b) Get rid of the Farm Program and its market-distorting subsidies.
Good Luck.
Is the use of organic cow manuree compost fertilizers (without biosolids)possibly helpful in improving the red tide problem?