Food web — a temperate lake through five trophic levels

{
  "nodes": [
    { "id": "sunlight", "type": "sun", "label": "Sunlight — the only external energy input", "x": 40, "y": 40, "width": 150, "height": 104, "fill": "#ede9fe", "stroke": "#6d28d9", "bold": true },
    { "id": "phytoplankton", "type": "leaf", "label": "Phytoplankton — 300 g C m⁻² yr⁻¹", "x": 215, "y": 40, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
    { "id": "daphnia", "type": "bug", "label": "Daphnia and copepods graze the algae", "x": 390, "y": 40, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
    { "id": "roach", "type": "ocean-wave", "label": "Roach and bleak — planktivorous fish", "x": 565, "y": 40, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
    { "id": "perch", "type": "ocean-wave", "label": "Perch — takes invertebrates and fry", "x": 740, "y": 40, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
    { "id": "pike", "type": "ocean-wave", "label": "Pike — top predator, trophic level 4.5", "x": 915, "y": 40, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
    { "id": "nutrients", "type": "water-drop", "label": "Nitrate and phosphate from the catchment", "x": 40, "y": 200, "width": 150, "height": 104, "fill": "#ede9fe", "stroke": "#6d28d9", "bold": true },
    { "id": "macrophytes", "type": "flower", "label": "Macrophytes in the littoral shallows", "x": 215, "y": 200, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
    { "id": "chironomids", "type": "bug", "label": "Chironomid larvae in the sediment", "x": 390, "y": 200, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d" },
    { "id": "mussels", "type": "hemisphere", "label": "Zebra mussels filter a litre a day each", "x": 565, "y": 200, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
    { "id": "heron", "type": "triangle", "label": "Heron and osprey take fish from above", "x": 740, "y": 200, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
    { "id": "efficiency", "type": "bar-chart", "label": "About 10% of energy crosses each level", "x": 915, "y": 200, "width": 150, "height": 104, "fill": "#ccfbf1", "stroke": "#0f766e", "bold": true },
    { "id": "detritus", "type": "layers", "label": "Detritus — dead plankton and leaf litter", "x": 40, "y": 360, "width": 150, "height": 104, "fill": "#dbeafe", "stroke": "#1d4ed8", "bold": true },
    { "id": "bacteria", "type": "petri-dish", "label": "Bacteria and fungi mineralise it", "x": 215, "y": 360, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
    { "id": "recycling", "type": "conveyor", "label": "Nutrients returned to the water column", "x": 390, "y": 360, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
    { "id": "mercury", "type": "cross", "label": "Methylmercury biomagnifies a millionfold", "x": 565, "y": 360, "width": 150, "height": 104, "fill": "#fee2e2", "stroke": "#b91c1c", "bold": true },
    { "id": "eutrophication", "type": "ocean-wave", "label": "Nutrient loading → bloom → anoxia", "x": 740, "y": 360, "width": 150, "height": 104, "fill": "#fee2e2", "stroke": "#b91c1c", "bold": true },
    { "id": "pyramid", "type": "pyramid-3d", "label": "Biomass pyramid inverts in midsummer", "x": 915, "y": 360, "width": 150, "height": 104, "fill": "#ccfbf1", "stroke": "#0f766e", "bold": true }
  ],
  "edges": [
    { "id": "e1", "source": "sunlight", "target": "phytoplankton", "thickness": 2.5 },
    { "id": "e2", "source": "nutrients", "target": "phytoplankton", "thickness": 2.5 },
    { "id": "e3", "source": "sunlight", "target": "macrophytes" },
    { "id": "e4", "source": "phytoplankton", "target": "daphnia", "thickness": 2.5 },
    { "id": "e5", "source": "phytoplankton", "target": "mussels", "label": "filtered straight out of the water" },
    { "id": "e6", "source": "macrophytes", "target": "chironomids" },
    { "id": "e7", "source": "daphnia", "target": "roach", "thickness": 2.5 },
    { "id": "e8", "source": "chironomids", "target": "roach" },
    { "id": "e9", "source": "daphnia", "target": "perch", "label": "young perch feed on plankton too" },
    { "id": "e10", "source": "roach", "target": "perch", "thickness": 2.5 },
    { "id": "e11", "source": "perch", "target": "pike", "thickness": 2.5 },
    { "id": "e12", "source": "roach", "target": "pike", "label": "pike take whatever is abundant" },
    { "id": "e13", "source": "roach", "target": "heron", "thickness": 2.5 },
    { "id": "e14", "source": "phytoplankton", "target": "detritus", "label": "the bloom that is not grazed" },
    { "id": "e15", "source": "mussels", "target": "detritus", "label": "pseudofaeces" },
    { "id": "e16", "source": "pike", "target": "detritus", "label": "carcasses sink" },
    { "id": "e17", "source": "detritus", "target": "chironomids", "label": "deposit feeding" },
    { "id": "e18", "source": "detritus", "target": "bacteria", "thickness": 2.5 },
    { "id": "e19", "source": "bacteria", "target": "recycling", "thickness": 2.5 },
    { "id": "e20", "source": "recycling", "target": "nutrients", "label": "the loop closes", "thickness": 2.5 },
    { "id": "e21", "source": "mercury", "target": "pike", "label": "the top predator carries the load", "style": "dashed" },
    { "id": "e22", "source": "efficiency", "target": "perch", "label": "why there are so few pike", "style": "dashed" },
    { "id": "e23", "source": "eutrophication", "target": "phytoplankton", "style": "dashed" },
    { "id": "e24", "source": "pyramid", "target": "daphnia", "label": "grazers can outweigh the algae", "style": "dashed" }
  ]
}