What environmental factor can increase the frequency of harmful algal blooms?

Harmful algal blooms (HABs) often thrive in warmer temperatures because these conditions can enhance algal growth and reproduction rates. Warmer water temperatures can create an environment that is more conducive to the proliferation of certain algal species, particularly those that can produce toxins. This response is frequently observed in various aquatic ecosystems, where rising temperatures, often associated with climate change, can lead to increased occurrences of blooms.

In contrast, cooler weather tends to inhibit algal growth due to lower metabolic rates and reduced reproductive cycles. Increased freshwater flow can dilute the concentration of nutrients in some cases, although it may also contribute to nutrient runoff, which can lead to blooms. Reduced nutrient input generally decreases the likelihood of blooms since nutrients such as nitrogen and phosphorus are essential for algal growth.