Phytoplankton
Phytoplankton are the microscopic plants that form the base of the food chain for all the world's oceans. Many Bigelow scientists, past and present, have studied these microscopic algae (e.g., Anderson, Balch, Christiansen, Goés, Guillard, Matrai, Sieracki, Wilson, CS Yentsch, CM Yentsch, Yoon). Because the world's oceans cover 71% of the earth's surface, the significance of phytoplankton is enormous. All animals (e.g., fishes, shellfish, sea birds, whales and worms) depend directly or indirectly on phytoplankton for their food (e.g., Fields, Larsen, Wahle). Phytoplankton are photosynthetic organisms that can convert carbon dioxide and water into basic sugars and oxygen using energy from the sun. These microscopic algae are responsible for approximately half of the earth's primary production. Or, to put it another way, marine phytoplankton are responsible for the oxygen in every other breath you take. Furthermore, marine phytoplankton were the original source of the organic carbon that, over geologic time, has been transformed by heat, pressure, and bacteria into petroleum (crude oil and natural gas). Today, billions of dollars are being invested in the large-scale production of algae for biofuel production, especially biodiesel production.
If the ocean life - and life on land - depends so much on phytoplankton, why does ocean water so often appear to be devoid of life? Divers can see long distances through the water as they swim through corals, whereas forests and grasslands have obvious trees and plants. How can this be possible? The answer is well known, and emeritus Bigelow scientists such as Guillard and Yentsch played key roles in finding that answer.
First, the oceans are broad and deep, and the numbers of phytoplankton cells in the oceans at any one instant in time is huge - conservatively estimated at 3 x 1023 cells. If these cells, averaging only 2 micrometers (two thousandths of a millimeter) in diameter, were placed end to end, they would form a cell chain that would extend from earth to moon and back 10 billion times! If the cells were organized to form the equivalent of a board of lumber that was 3 inches by 12 inches, the board would extend from the Earth to the moon. You could walk to the moon on a board made of the amount of phytoplankton that exists in the ocean at any one time. But this is only part of the answer.
Second, the cells are growing, dividing into two cells, and being eaten constantly. On average, a phytoplankton cell divides once per day, and on average, one of the two cells is eaten. In other words, each day the oceans produce a second board from the earth to the moon, and the organisms in the oceans eat one of the boards. This rapid pace of cells growing, dividing, and being eaten means that the oceans are very productive, but we see little evidence of the productivity.
On land, a very different story emerges. Cells may still be dividing once per day, but they are not eaten at the same rate. Cells accumulate in trees, sometimes for several centuries, before the tree trunk falls to the forest floor and is eaten by worms, insects, fungi, bacteria, etc. Plant life on land and in the oceans is fundamentally different. Bigelow scientists have helped describe this difference.
Phytoplankton are also very diverse. Some, known as cyanobacteria or blue-green algae, are simple forms that resemble bacteria. Other algal cells have a nucleus, and contain a chloroplast, a mitochondrion, and so forth, like typical plant cells and animal cells (animal cells lack chloroplasts, however). Some are simple, round cells that look like tiny green, brown, or red balls, while others have various shapes and even elaborate ornamentation. Some are naked cells, like animal cells; others have cell walls like plant cells. But it doesn't end there. Diatoms have cell walls made of glass - the same opaline glass that we use for windows. Coccolithophores have calcium carbonate scales that surround the cells, and these scales may have profound influences on ocean optics (Balch, Goés, Wilson). Still others have silica, carbohydrate, or proteinaceous scales. Dinoflagellate cells are often surrounded by armor-like plates. Not only is phytoplankton morphology diverse, but genetically the organisms are very different. Several groups are so different that even a cow and an oak tree are more similar than they are. Bigelow scientists are interested in the ecology of phytoplankton (Balch, Christiansen, Fields, Goés, Matrai, Sieracki), their cell/molecular biology (Anderson, Stepanauskas, Wharam, Wilson, Yoon), their genomics (McClellan, Wharam, Wilson, Yoon) and their taxonomy (Anderson, Yoon).