Aug 27, 2016

The mega challenge of marine microplastics: getting them off Mother Nature's menu.

Crustacean larvae full of plastic  microbeads
Microplastics and larger plastic bits in saltwater or fresh are problematic for the fish, birds, crustaceans, bivalves and other organisms that ingest them. How do we keep plastic out of their diets?

Recent research suggests that the key attraction of the plastic bits to fishes, birds and invertebrates is the flavor/odor of the biofilm of bacteria that has colonized these plastic particles as solid habitats.

Like other organisms, bacteria eat and breathe and emit wastes andsignaling chemicals. Those emissions are attractive to animals from protozoa to invertebrates and vertebrates, who treat the plastic particles as though they were mini-wontons or micro- matzo balls.

Since we won't be training Mother Nature to avoid plastic, and we aren't likely to stop manufacturing and using the stuff any time soon, can we make plastic unattractive to microbes?
Plastic makers have been required to tweak their products chemistry to protect public health, so it is not impossible to require plastic people to make their stuff unattractive to marine bacteria, or freshwater ones.
Pastic-filled bird carcass & plastics taken from it
But that raises more questions:
While you _could_ add an antibacterial to the plastic, the ubiquity of the plastic bits in the bays and seas is such that you would be filling the water column with antibacterial chemical-emitting particles - specifically geared toward repelling or killing natural marine or freshwater bacteria that live there.
That's not a good way to go.. How else to make plastic unappealing to marine bacteria?

Lethal effects of Atlantic Salmon smolt exposure to aluminum-rich acidic waters - peer reviewed studies suggest similar conditions prevail at Penobscot River mouth.

Below, read a variety of scientific reports on the mortality of Atlantic salmon smolts exposed to acidified freshwater, brackish water and/or saltwater contaminated with dissolved aluminum. About Salmon smoltification 

 There is a general consensus among the scientific community that exposure of Maine salmon smolts to pulses of low pH water carrying dissolved aluminum triggers premature smoltification
The culprit appears to be accumulation of gill surface aluminum, "leading to substantial alterations in gill morphology, reduced gill Na+/K+-ATPase (NKA) activity, and impaired ion regulation in both freshwater and seawater."

Are Penobscot  River's  Atlantic Salmon smolt  affected by declines in Penobscot River in part due to such acid/aluminum-rich water pollution in Stockton Harbor since the 1950s  in waters just outside the mouth of Penobscot River.  There on Stockton Harbor's Kidder's Point,  acid, sulfur and aluminum wastes have eroded, leached and plumed into the southwest end of  the harbor whose connection with  abandoned sulfuric acid, fertilizer and alum production complex on the harbor's Kidder Point. Tests since the 1980s document these conditions.

Consensus on adverse impacts.
The impact of this mixture of acid sulfur and aluminum on Atlantic salmon smolts has been well documented since at least the late 1980s by researchers in the USA, Canada, Norway and elsewhere.
Topical Searches
* Google Scholar Aluminum + estuarine
* Google scholar: aluminum + estuary +Maine
* Pub Med search on estuarine and aluminum


Effect of aluminum on fish in acidic waters. A term paper submitted to
The Department of Ecology and Natural Resource Management (INA)
Agricultural University of Norway, 2004 

Effects of Acidity and Aluminum on the Physiology and Migratory Behavior of Atlantic Salmon Smolts in Maine, USA  J. A. Magee, T. A. Haines, J. F. Kocik, K. F. Beland, S. D. McCormick, Water, Air, and Soil Pollution: Vol 130, Issue 1, pp 881–886 August 2001, 

Other species 
Watershed scale & chemistry studies of aluminum & acids' bio-impacts