<form class="form-inline">
  <div class="form-group">
    <label id="lower_bound_label"
           for="lower_bound_range_input">
    </label>
    <input class="form-control hidden"
           id="lower_bound_range_input"
           type="range"
           min="0">
  </div>
  <div class="form-group">
    <label id="upper_bound_label"
           for="upper_bound_range_input">
    </label>
    <input class="form-control hidden"
           id="upper_bound_range_input"
           type="range"
           min="0">
  </div>
</form>

<noscript>
  <br>
  <div class="alert alert-danger">
    <h1>JavaScript required</h1>
    <p>
      This visulisation requires JavaScript to work.
    </p>
  </div>
</noscript>

<div id="loading-notification">
  <h2>Visualisation loading...</h2>
  <div class="progress">
    <div class="progress-bar progress-bar-striped active"
         role="progressbar"
         style="width: 100%">
    </div>
  </div>
</div>

<svg style="width: 100%;"
     height="auto"
     viewBox="0 0 1000 1000"
     data-url="<%= root_taxon_path(@content_item.content_id, format: "json", cache: params[:cache]) %>"
     data-module="bubbles-visualisation">
</svg>

<form class="form-inline">
  <div class="form-group">
    <label id="lower_bound_label"
           for="lower_bound_range_input">
    </label>
    <input class="form-control hidden"
           id="lower_bound_range_input"
           type="range"
           min="0">
  </div>
  <div class="form-group">
    <label id="upper_bound_label"
           for="upper_bound_range_input">
    </label>
    <input class="form-control hidden"
           id="upper_bound_range_input"
           type="range"
           min="0">
  </div>
</form>

<noscript>
  <br>
  <div class="alert alert-danger">
    <h1>JavaScript required</h1>
    <p>
      This visulisation requires JavaScript to work.
    </p>
  </div>
</noscript>

<div id="loading-notification">
  <h2>Visualisation loading...</h2>
  <div class="progress">
    <div class="progress-bar progress-bar-striped active"
         role="progressbar"
         style="width: 100%">
    </div>
  </div>
</div>

<svg style="width: 100%;"
     viewBox="0 0 1000 1000"
     data-url="<%= root_taxon_path(@content_item.content_id, format: "json", cache: params[:cache]) %>"
     data-module="bubbles-visualisation">
</svg>

Remove height=auto from the bubbles SVG element
Remove height=auto from the bubbles SVG element
