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Pennsylvania ‘megahatchery’ fouling stream and Chesapeake
Effort to clean up Pennsylvania fish hatcheries may help Chesapeake
Fast food diet bad for Bay’s tiniest animals / New criteria would improve quality of algae available in Chesapeake’s food web
Plankton comes from a Greek word meaning "wander or roam." German biologist Viktor Hensen coined the term in 1887 to collectively describe all forms of floating or drifting life in natural waters. Phytoplankton is derived from the combination of plankton and the Greek word, phuton or plant.
Plant plankton, which capture energy from sunlight and turn it into organic cell material, form the base of the aquatic food chain. These cells are eaten by small animal organisms, principally animal or zooplankton, which are in turn fed upon by the juvenile or filter-feeding adults of still larger species and so on up to menhaden, striped bass and bluefish which are consumed by humans and our industries.
In 1924, a manuscript by J. Johnstone, A. Scott and H.C. Chadwick made the connection between nitrogen in the seawater column and the succession of one species after another during the passage of seasons. Sir Alistair Hardy-knighted for his contributions to science-stated a hypothesis in 1935 that "dense concentrations of planktonic plants may produce an effect in the water which is uncongenial to animal life." In this, he anticipated today's wide recognition that plankton blooms of some organisms can be associated with fish kills.
Hardy developed a "plankton recorder," which when towed through the water, channeled the passing stream of organisms onto a strip of fine gauze which was spooled on a reel along with a second layer of equally fine cloth, keeping the layers of plankton samples separate. Like a strip of movie film, this was later uncoiled and drawn inch by inch across the stage of a microscope. The organisms, their kinds and abundances, were laboriously recorded by an expert, and the data tabulated to provide a trace of life through the swath of ocean travelled, sometimes as far as 100 miles.
The distribution of plankton in the sea was quickly recognized to be discontinuous, with patches of dense growth of one species replaced in a short distance with another.
It was also clear that phytoplankton and zooplankton reappeared annually at relatively predictable times of year, particularly in early spring, when late winter seasonal storms caused nutrient-rich runoff to enter coastal waters. While the numbers of these cells varied, the timing of appearance for individual species was somehow related to changes in water temperature, increasing intensity of sunlight and salinity.
In the late 19th century, after many years of data in England and Europe, a connection was made between plankton abundance and the commercial take of herrings in the coastal fishery.
Along U.S. East Coast estuaries, Dr. Thurlow Nelson of Rutgers University once noted that the appearance of the abundant and easily recognized plankton diatom, Skeletonema costatum, was so connected with success of the oyster harvest that it was truly a "million-dollar diatom."
In the 19th century, the quality of microscopes inproved, allowing researchers to make accurate drawings by which individual species could be identified with certainty. Many of these were done with camera lucida, a device that allowed the artist to see an image of the cell apparently projected on the paper while being drawn.
A group of Philadelphia physicians who met at the Academy of Natural Sciences of Philadelphia were among these illustrators. They had been banded together in 1858 by Joseph Leidy, who at the age of 10, created a lovely book of drawings, "Joseph Leidy's Book of Shells-1833."
In his adult years, he was described as "the last man who knew everything." An 1859 photograph shows him in his laboratory with a microscope. By the 1870s, he was among the first to recognize the ecological decline of the Schuykill and Wissahickon rivers as their microscopic life died. (He was also interested in larger life forms: dinosaurs, then barely more than a puzzling geological discovery. He was responsible, in 1868, for the first mounted, erect skeleton of Hadrosaurus foulkii, a duckbill dinosaur that roamed where New Jersey is today.)
Their illustrations, as well as those created by others, were published in monographs. Some of the oceanic phytoplankton cells are stunningly beautiful. This is especially true for diatoms, in which each cell is encased in an often ornate frustule of silica, which is extracted by the organisms from seawater and synthesized into astoundingly regular geometric patterns.
Skilled microscopists used probes finer than human hair to arrange the cleaned frustules of diatoms on rectangular glass slides. A drop of transparent medium, such as balsam, was put in place along with a thin glass coverslip covering, then slowly heated. (Later investigators had good results making temporary mounts with Karo syrup.) When this cooled and solidified, a permanent mount had been created through which each diatom could be examined at high magnification.
A mounting medium with the right index of refraction makes the exquisite detail of each frustule stand out in stark relief. With accompanying documentation, the permanent mounts were sent all over the world and many of these classic preparations still exist.
In the 20th century, photography was used, but suffered from the poor depth of field-the problem of lenses being unable to focus simultaneously on parts of an object both near and more distant-which made parts of many images fuzzy and less useful for identification and understanding the cells' structures.
In the 1950s, when Dr. Ruth Myrtle Patrick and Charlie Reimer began their epic-and yet unfinished-"Diatoms of the United States," they chose to use beautifully inked illustrations for their work.
Patrick was the daughter of Frank Patrick, a Midwest lawyer interested in science. He nailed a can to the end of a stick and would dip stuff from ponds and the like to show young Ruth. He set a microscope up on a box, and she'd climb on his knee to look through the eyepiece-and was hooked. He left her with his motto: "Remember, you've got to leave this world better because you have passed this way." Most notably, she became one of the very early female researchers in aquatic science.
Patrick got her master's and doctorate degrees from the University of Virginia, married Charles Hodge IV in 1931, and worked part-time at the Academy of Natural Sciences in Philadelphia as an associate curator from 1939 to 1946. She recalls overhearing the academy's herpetologist remark: "Ruth is slipping." Queried, the man explained it was because she was wearing lipstick. Ruth pointed out one well-known Philadelphian who also wore lipstick, but was admonished, "but you have a Ph.D."
At a 2003 affair in her honor at the Academy's Dinosaur Hall, Patrick looked up at the balcony and described those years with good humor. "The systematists (taxonomists who identify and catalogue organisms) were ranged around this balcony in cubicles and would have spirited controversies. Once, an altercation broke out and one of them fell down here to the floor [a plunge of 15-20 feet] and had to be taken for medical help".
Another time, when the Academy was in tight financial straits, Patrick recalled that a ball was to be held in this same space. "Peggy Dilks and I cleaned the bathrooms; there was only one maintenance man for the whole place."
Patrick's research focused on diatoms by 1935. After looking at modern species and fossils deep in the sediments of Utah's Great Salt Lake, she recognized that they were a bellwether of environmental conditions.
In 1947, Patrick founded and was made chairperson of the academy's Limnology Department. Given a staff and resources at her command, she looked for ways to make the institution grow. In 1949 and 1950 her papers proposed "A biological measure of stream conditions based on survey(s)."
Meanwhile, problems with industrial effluents began appearing in East Coast estuaries. In 1950, the Woods Hole Oceanographic Institution reported that a local Long Island, NY, oyster fishery had collapsed through a "failure to fatten" that researchers had associated with billions of tiny, yet unidentified algae cells that were harmful to oysters. The algae's appearance correlated with the expansions of duck farming operations, which drained into the estuary.
By 1956, Patrick and M.H. Hohn had introduced the "Diatometer," a tool for determining the condition of aquatic life. This device was a tethered float with a carrier containing several clean glass microscope slides, upon which the microscopic diatom cells could colonize. While quite simple, it was unique at the time and was patented.
Patrick and her colleagues also made the connection between shifts in the species of diatoms as environmental conditions went from healthy to stressed-or back. The diatoms were cleaned, to make them transparent and more accurately identified and counted. The record was archived for later study and verification. These were her "biological canaries."
Patrick proposed this as a means of analysis for problems resulting from natural or industrial disturbances in an increasingly pollution-conscious United States. She espoused and stated the mantra: "Use (of an aquatic resource) without abuse" and many corporations liked the sound of that.
Three years later, in 1959, she published "How is Industry Meeting its Responsibility in Keeping Streams Clean" at the Seventh Annual Pennsylvania Clean Streams Conference.
She had struck a chord with management, and clients began to seek out the academy for help: sewage plants, auto manufacturers, power plants, nuclear installations. Diatometers and other measuring systems were deployed in rivers, streams, lakes and estuaries, in effluents and on oyster bars. They were also used as acute toxicity assays. This rapidly became a big business relative to the modest budgets most scientists worked with at the time. Her version of environmental consulting was born.
Her relationship with industry, growing throughout the 1960s, was not without criticism. Patrick once said: "I was considered almost a woman of the street" at the time. L. Eugene Cronin, director of the Chesapeake Biological Lab, said that he thought of Patrick-and those of us who worked for her in the Limnology Department-as "bi-ostitutues." He accused many environmental consultants of using data on living organisms to justify industrial activity, and claim no harmful effects.
Elewhere, ecologist Joel Hedgepeth wrote in 1957 that surveys in estuaries had begun in Australia, South Africa and North America. He noted that "an institute devoted to the problems of Chesapeake Bay has been established," referring to Johns Hopkins University's Chesapeake Bay Institute.
Most plankton collections from the water column up to that point had been made using towed nets, made of silk (or later nylon) bolting cloth that could strain out particles using a mesh of 200 threads to the inch.
By the mid-60s, it was recognized that most phytoplankton cells were extremely small and passed through any kind of net strainer. Biologists began collecting whole water samples, to which preservatives had been added, and examining the cells that settled out. This was the age of recognizing "nanoplankton" cells on the order of a few thousandths of a millimeter in diameter or smaller. These cells were vastly more abundant than the obvious "net plankton" species.
Eventually, Shirley Van Falkenburg and David Flemer, at the University of Maryland, and others, demonstrated that this fraction of small cells escaping the nets was actually accomplishing more photosynthesis than all of the larger cells combined.
Around that time, I was doing my graduate work on the plankton of increasingly eutrophic Barnegat Bay, NJ, which was undergoing rampant development and a population explosion.
Deeper into my studies in the late 1960s, I began recognizing yet another class of cells: immense numbers of almost submicroscopic organisms that far outnumbered all the net-plankton and nanoplankton combined. It was as if a new class of cells had been superimposed upon a normal community of other species. Were they algae? Bacteria? Some workers named these tiny organisms Nannochloris atomus amid a growing awareness of a whole class-and a number of species-of extremely small picoplankton species.
I archived and preserved each sample in small vials, storing hundreds of these in small fitted cases.
In 1971, I was hired by Patrick and went to work at the Academy of Natural Sciences' Laboratory in Benedict, MD. I continued to sample and count phytoplankton on the mainstem Bay as well as the Patuxent and Potomac rivers. I was surprised to find very few of these tiny picoplankton cells in my samples.
For seven years, I identified and made counts of the cells in connection with other physical and biological variables at a number of stations every couple of weeks throughout the year. That data was archived and has been used by other workers in the later Baywide monitoring program.
As at Barnegat, purely as a quality assurance hedge against my own errors, I archived each sample in similar vials. Some time after my departure from the Academy, these cases of vials were also discarded.
In the 1980s, immense numbers of tiny picoplankton cells, similar to those in Barnegat more than a decade earlier, were showing up in the Chesapeake. These now seem to be the first sign of brown tide epidemics, which now sporadically plague many East Coast estuaries.
I would like to go back, or have someone else go back, and put my old samples-now discarded-under a microscope and say: "Hey, those are early signs of the same stuff we are seeing today. Let's see if we can associate it with increases in population, or changes in land use or social practice."
The skills of present-day phytoplankton taxonomists, as well as the tools at their disposal, are far beyond the primitive methods available during my years working on Chesapeake Bay. What society chooses to do with them is up for grabs.
