Instead of a new WP_Query, use the pre_get_posts
filter
add_filter('pre_get_posts', 'custom_query');
function custom_query($query) {
if($query->is_main_query() && $query->is_author() && $_GET['eco']=='somemetakey') {
$query->set('meta_query', array(
array(
'key' => 'somemetakey',
'value' => $query->get('author')
)
));
}
}