Led by David Foster (pictured to the right), students ventured out to spend a total of 6 hours in Harvard Forest. Two of those hours were spent meeting researchers and exploring the forest's landscape. The other four were spent coring sediments in Black Gum Swamp that dated back as far as 15,000 years!
Below, students are pictured in sediment coring and analysis. Following the slideshow is a written analysis of what they found. |
Coring for Sediment
Analyzing Sediment in the Lab
Written Analysis
20 cm:
Tristan: Large organic matter, soft and moist. Grain, twigs, dark brown-black hard chunks, dirty, poorly sorted, lacks consistency, doesn’t hold together well, intact organic matter, “topsoil”. Rock: speckled, lustrous, quartz like. Soil piece: not solid, stringy filaments, roots possibly, small particles. Bark: a chunk like bark, porous.
70 cm:
Sally: Intact stems, woody materials, coarse with tiny rocks, and dark brown in color.
Stefanie: Wooden remains, slimy dark color. After rinse: chunks of wood, red color, up to about 1.5” in length, bark? Under microscope: orange/red clips of wood, twigs. Fine sift: light and dark colored bits of wood -> remains of trees? Spongy bits.
Nayab: Before cleaning: Big, dark, brown stems, and pieces of bark. Through microscope: Big pieces: Dark brown bark, stems, red twigs. Small pieces: Many different colors; small pieces of dark bark; light orange spongy material.
75 cm:
Tristan: Dark uniform in color, several large pieces, finer sediments. Big black chunk charcoal: compact coarse degrades to a fine material, fine lines, black powder, striated, pretty. Roots: filaments, white clear tendrils.
150 cm:
Sally: Bigger pieces of bark that are easy to break apart, dark in color.
Stefanie: Large wooden pieces. Post rinse: chunks of red wood, up to 1 inch long, rough texture. Remains of twigs, shrubs, grasses, stem of vascular plant?
Nayab: Before cleaning: Huge pieces of bark ~ 1 inch! Through microscope: Big pieces: Red-brown, rough textured bark. Small pieces: Bark, grass (could be shrubs).
210 cm:
Sally: A lot of leaves, big stems part of trees, stringy material found that can be tiny roots or moss, dark mud with lighter areas of leaves.
Stefanie: Large chunks of wood, pieces of leaves. Post sift: leather leaf shrub remains, stringy, translucent brown leaves. Fine sift: many leaf and twig remains, varied textures, spore capsule, moss, waterlogged shrubs and moss, well preserved.
Nayab: Before cleaning: Big twigs (some has branches), lots and lots of brown leaves. Through microscope: Big pieces: Leaves, veins from leaves, which we learned from Professor Foster were leather grass (the same type of grass we saw the previous day in the marshes!); lots of moss. Small pieces: Possible spore capsules that were squishy, sphere-like.
250 cm:
Tristan: Clay-like with fine material but also uniform with pieces of organic material, soggy but rigid enough to sift through, dark and milky brown. “Spider”: planty, coral-like possibly moss, perhaps a frond, star shaped, radial leaf. Football-shaped seed: very smooth, very solid, subtle hand texture.
300 cm:
Sally: Homogeneous mud/sediment, everything washed through the top sifter, bottom left with fine material and sediments. Found spores and seed pod or seed coat.
Stefanie: Homogenous, dark, smooth. Very fine bits. Small, light-colored, spongy balls. Broken with white -> spores? Seed pod fragment. Leaf pieces.
Nayab: Before cleaning: Homogeneous, squishy, dark brown composition. Through microscope: Big pieces: None. Small pieces: More possible spores that are yellow, brown, and bumpy; there was also possible seed pods that were white, hollow, and with a rectangular shape.
310 cm:
Tristan: Feels like a melted Hershey's.
450 cm:
Sally: Lake sediment, greenish black tint. tiny balls can be seen under the microscope that could be spores, and translucent twigs.
Stefanie: Course, fine, slimy, dark color. Few decaying tiny twigs and leaves, lattice work of decaying leaf. Tiny spongy bits, few twigs.
Nayab: Before cleaning: Similar composition to 300 cm sample, but more coarse. Through microscope: Big pieces: None. Small pieces: decomposed spongy matter, tiny twigs.
500 cm:
Tristan: Fine grain, dark but some pieces of light brown chunks, clay-like, wells sorted, uniform. Twig: well preserved, fibrous compact, grainy, brown, dark outside, orange rust inside, cool uniform, porous, translucent, orange sparkles. Thin mineral flake: (orange sparkles), like mica, lustrous but not consistent.
Tristan: Large organic matter, soft and moist. Grain, twigs, dark brown-black hard chunks, dirty, poorly sorted, lacks consistency, doesn’t hold together well, intact organic matter, “topsoil”. Rock: speckled, lustrous, quartz like. Soil piece: not solid, stringy filaments, roots possibly, small particles. Bark: a chunk like bark, porous.
70 cm:
Sally: Intact stems, woody materials, coarse with tiny rocks, and dark brown in color.
Stefanie: Wooden remains, slimy dark color. After rinse: chunks of wood, red color, up to about 1.5” in length, bark? Under microscope: orange/red clips of wood, twigs. Fine sift: light and dark colored bits of wood -> remains of trees? Spongy bits.
Nayab: Before cleaning: Big, dark, brown stems, and pieces of bark. Through microscope: Big pieces: Dark brown bark, stems, red twigs. Small pieces: Many different colors; small pieces of dark bark; light orange spongy material.
75 cm:
Tristan: Dark uniform in color, several large pieces, finer sediments. Big black chunk charcoal: compact coarse degrades to a fine material, fine lines, black powder, striated, pretty. Roots: filaments, white clear tendrils.
150 cm:
Sally: Bigger pieces of bark that are easy to break apart, dark in color.
Stefanie: Large wooden pieces. Post rinse: chunks of red wood, up to 1 inch long, rough texture. Remains of twigs, shrubs, grasses, stem of vascular plant?
Nayab: Before cleaning: Huge pieces of bark ~ 1 inch! Through microscope: Big pieces: Red-brown, rough textured bark. Small pieces: Bark, grass (could be shrubs).
210 cm:
Sally: A lot of leaves, big stems part of trees, stringy material found that can be tiny roots or moss, dark mud with lighter areas of leaves.
Stefanie: Large chunks of wood, pieces of leaves. Post sift: leather leaf shrub remains, stringy, translucent brown leaves. Fine sift: many leaf and twig remains, varied textures, spore capsule, moss, waterlogged shrubs and moss, well preserved.
Nayab: Before cleaning: Big twigs (some has branches), lots and lots of brown leaves. Through microscope: Big pieces: Leaves, veins from leaves, which we learned from Professor Foster were leather grass (the same type of grass we saw the previous day in the marshes!); lots of moss. Small pieces: Possible spore capsules that were squishy, sphere-like.
250 cm:
Tristan: Clay-like with fine material but also uniform with pieces of organic material, soggy but rigid enough to sift through, dark and milky brown. “Spider”: planty, coral-like possibly moss, perhaps a frond, star shaped, radial leaf. Football-shaped seed: very smooth, very solid, subtle hand texture.
300 cm:
Sally: Homogeneous mud/sediment, everything washed through the top sifter, bottom left with fine material and sediments. Found spores and seed pod or seed coat.
Stefanie: Homogenous, dark, smooth. Very fine bits. Small, light-colored, spongy balls. Broken with white -> spores? Seed pod fragment. Leaf pieces.
Nayab: Before cleaning: Homogeneous, squishy, dark brown composition. Through microscope: Big pieces: None. Small pieces: More possible spores that are yellow, brown, and bumpy; there was also possible seed pods that were white, hollow, and with a rectangular shape.
310 cm:
Tristan: Feels like a melted Hershey's.
450 cm:
Sally: Lake sediment, greenish black tint. tiny balls can be seen under the microscope that could be spores, and translucent twigs.
Stefanie: Course, fine, slimy, dark color. Few decaying tiny twigs and leaves, lattice work of decaying leaf. Tiny spongy bits, few twigs.
Nayab: Before cleaning: Similar composition to 300 cm sample, but more coarse. Through microscope: Big pieces: None. Small pieces: decomposed spongy matter, tiny twigs.
500 cm:
Tristan: Fine grain, dark but some pieces of light brown chunks, clay-like, wells sorted, uniform. Twig: well preserved, fibrous compact, grainy, brown, dark outside, orange rust inside, cool uniform, porous, translucent, orange sparkles. Thin mineral flake: (orange sparkles), like mica, lustrous but not consistent.