Ocean Month: The Impacts of Pesticides From Mauka to Makai

As HFC’s Ocean Month draws to a close, we wanted to highlight the amazing work being done on Maui to reduce pesticide use and protect oceans. Duane Sparkman and organizations like Maui Nui Marine Resource Council are leading the charge for a healthier, safer Maui and for cleaner oceans.

Aloha, I’m Duane Sparkman, owner and operator of Edaphic Perspective, an organic consulting company based in Hawaii. Doing landscape work in Hawaii for the past 25 years has allowed me to build great partnerships with science based nonprofits and developers in this ever changing environment. With assistance from Beyond Pesticides, Maui Nui Marine Resource Council, Hawaii SEED, Hokunui Environmental Solutions, County of Maui Parks Department, Wailea Community Association and Makena Golf Course, we are working to create a chemical free future here on Maui.

Maui Nui Marine Resource Council (MNMRC), based on Maui, has identified several culprits of reef degradation. Founded in 2007, Maui Nui Marine Resource Council works from the mountains (mauka) to the sea (makai) to enact smart, sustainable, science based solutions in concert with traditional Hawaiian values to address challenging environmental problems. Their vision is clean ocean water, healthy and vibrant coral reefs, and an abundance of native fish populations.

What is Driving Reef Decline and Ocean Pollution?

In protecting these treasured islands, this organization works against toxins poisoning our waters and the irreplaceable ecosystems within them. One of the primary contributors to reef degradation is fertilizer. Water soluble nitrogen, present in fertilizers, has been shown to promote the growth of invasive algae, which then blankets the reefs and cuts off the essential sunlight that is utilized to sustain coral colonies. Another ingredient in fertilizers, phosphorus, has been linked to rapid coral growth, elongating the coral and therefore causing it to become brittle and susceptible to breaking off during heavy wave action, which subsequently slows colony growth.

Another critical driving factor of coral degradation is climate change and the rapidly rising ocean temperatures that come with it. Warmer ocean waters lead to coral bleaching, a phenomenon that refers to the coral heads turning white as a result of the coral expelling the beneficial algae (zooxanthellae) they rely on.

Turbidity

Hokunui Environmental Solutions spraying their compost tea at a test plot at a ballfield in Keopuolani Park in Kahului, HI.

A driving factor of reef decline is turbidity, or when water becomes cloudy, opaque, or thick with suspended matter. Turbidity is often caused by sediment runoff, and is made worse by the use of synthetic herbicides and pesticides. These synthetic products destroy microbial life in soil, which has ripple effects throughout marine and terrestrial ecosystems, including ocean life. Protozoa, fungus and bacterial chains hold soil together and bind nutrients to the soil, which makes nutrients unavailable if there is runoff into the ocean. When this microbial life is killed by synthetic pesticides, nutrients from the soil run-off into the ocean and contribute to algae blooms and turbidity.

Turbidity is detrimental to coral, as coral needs sunlight to survive, and cloudy, turbid water blocks the sunlight. The suspended matter in turbid water also often carries excess nutrients which further contributes to coral decline.

What's being done?

To reduce turbidity, it is critical that we implement organic land management. Through promoting soil health, organic land care helps to reduce sediment and nutrient runoff, also reducing turbidity. In Hawai’i, areas managed organically have healthier soil, which has slowed landslides along highways and subsequently helped to reduce turbidity. To further reduce this ocean pollution that decimates coral populations, we worked in collaboration with a non-profit partner, Beyond Pesticides, and consultant Chip Osborne to develop a reef friendly fertilizer. Compost, compost teas, and worm teas are all other viable alternatives to fertilizers that do not negatively affect coral health or contribute to turbidity..

Sediment capture is also being implemented in most coastal developments in Hawai’i to reduce turbidity. Large retention basins capture stormwater and sediment by allowing the water to percolate through the soil while the sediment is trapped in the basin, as opposed to flowing directly into the ocean.

Maui Nui Marine Resource Council has partnered with Edaphic Perspective and Hokunui Environmental to assist the County of Maui, homeowners associations, private golf courses and resorts to begin the transition to organic land management. So far there are three test sites and two resorts using compost tea to support the transition to more holistic, reef-friendly landscaping practices. There is also interest from many private landowners to switch to organic land care, but the current primary obstacle is having the resources to provide the products, maintenance and installation services to interested parties. These challenges are currently being addressed as we collaborate with multiple stakeholders to create viable solutions to combat coral loss.

As we focus on ensuring ocean health for generations to come, we look forward to making organic land care a priority in Maui.