15
Mar
Coral Reefs Under Threat by Glyphosate, Toxic Pesticides
(Beyond Pesticides, March 15, 2024) Toxic pesticides harm all beings and ecosystems, including coral reefs. Large benthic foraminifera (LBF) are single-celled organisms found on reefs that face adverse metabolic impacts after exposure to the weed killer glyphosate and insecticide imidacloprid, according to a study published in Marine Pollution Bulletin. The study found that “even the lowest doses of the fungicide and herbicide caused irreparable damage to the foraminifera and their symbionts.†Beyond Pesticides reiterates our mission of banning toxic petrochemical pesticides by 2032 and that this goal applies to land and water exposure to pesticides. LBFs are typically used as bioindicators for coral health because they are found in substantial quantities and gathering data is not intrusive or damaging to reef health.
Researchers in this study screened three different herbicides (one insecticide, one fungicide, and one herbicide) at three different concentration levels. The experiments were performed in six well-samples, each with 10mL of filtered artificial seawater and a singular LBF. The control plates are artificial seawater and the experimental plates include artificial seawater with the addition of three pesticides (imidacloprid, glyphosate, and tebuconazole). Each pesticide was applied at low, medium, and high doses to measure the direct impacts of each pesticide after dilution in seawater. The research team conducted two different experiments, one based on pulse-amplitude-modulation (PAM) fluorometry and the other to measure isotopic uptake. For the PAM fluorometry experiment the researchers “measured the photosynthetic performance of the photosymbionts [an organism in a photosymbiotic relationship] for two weeks at days 1, 3, 5, 7 and 14 using variable chlorophyll fluorescence imaging of photosystem II (PSII; Imaging PAM Microscopy Version–Walz GmbH; excitation at 620 nm). Measurement of the variable fluorescence over the maximum quantum yield fluorescence (Fv/fm) estimates the efficiency of photosystem II []. Fv/fm serves as a proxy for the vitality of the photosymbionts [] and therefore it can be used as an indicator of the health of the foraminifera themselves [].†In terms of the isotopic uptake experience, “Two-way ANOVAs (level of significance p = 0.05) were run to test if the type of pesticide, the concentration and/or incubation time significantly affected uptake of 15N and 13C, respectively. Significant results were further analyzed for group differences using Tukey’s post hoc test (level of significance p = 0.05).â€
This study differs from existing literature in how the researchers quantified the impact based on amount of pesticide products rather than solely on the individual pesticides that make up the main ingredient of the targeted products. “Roundup© [with the active ingredient glyphosate] only contains 1 % glyphosate, in Pronto©Plus the active substance tebuconazole has 13.6 % and in Confidor© the imidacloprid concentration is 20 %, according to the manufacturer’s information,†says the research team. “Based on that, the concentration of active pesticide substances, which can be found in the environment are not a factor of 10 smaller than ours tested, they are approximately the same concentration or even 10 times higher.†The scientists in this study found that, “the photosynthetic area decreased as the amount of pesticide added increased and as the incubation time increased.†Glyphosate-based Roundup Ready in particular “caused a reduction of the photosynthetic area in all foraminifera…independent of concentration.†The scientists also found that, “Foraminiferal [inorganic carbon] 13C uptake was significantly reduced at the highest pesticide concentration compared to the control (p < 0.001). The herbicide and fungicide showed comparable reductions of 13C uptake (p = 0.945), the reduction caused by the insecticide was less pronounced.â€
Oceans and water advocates continue to remind elected officials that we cannot talk about climate action without talking about oceans and waterways stewardship. Bodhi Patil, a UN-recognized oceans solutionist and co-creator of Ocean Uprise, a global activist accelerator initiative, guides his advocacy with the understanding that ocean health is human health. “Mitigating toxic pollutants, excess fertilizers, pesticides, and chemicals entering upstream water bodies and flowing into downstream reef ecosystems is a direct way to reduce the stressors on critically important coral reefs†says Bodhi. “Improved water quality and reduced water pollution will contribute to their long-term health and climate resiliency. We have to think about the ocean as a being that is connected to all waterways, because she is!â€
Advocates have worked tirelessly to codify ocean rights in a United Nations-recognized framework as the impacts of toxic pesticides continue to impact ocean creatures big and small. In 2023, due to the years of advocacy by people like Bodhi, 193 nations approved the draft version of the High Seas Treaty (also known as Biodiversity Beyond National Jurisdiction), an international framework that establishes universal rights to protect the oceans from harm. To date, 88 countries have signed the treaty and two countries (Chile and Palau) have ratified the treaty in their national legislatures. At least 60 countries must ratify the High Treaty for it to become international law. The exorbitant loss of over 90% of planktonic organisms from the 1940 baseline is analogous to the decline in terrestrial pollinator loss over the past several decades. Additionally, “In its 2017 risk assessment for the most widely used neonicotinoid, imidacloprid, EPA found, ‘[C]oncentrations of imidacloprid detected in streams, rivers, lakes and drainage canals routinely exceed acute and chronic toxicity endpoints derived for freshwater invertebrates.’ The agency evaluated an expanded universe of adverse effects data and finds that acute (short-term) and chronic (long-term) toxicity endpoints are lower (adverse effects beginning at 0.65 μg/L (micrograms per liter)-acute and 0.01 μg/L-chronic effects) than previously established aquatic life benchmarks (adverse effects from 34.5 μg/L-acute and 1.05μg/L-chronic effects).†Beyond Pesticides has reported on the linkage to the climate crisis and toxic petrochemical pesticide use in relation to aquatic organisms, oceans, and water.
Beyond Pesticides acknowledges the intersectional nature of the climate crisis and that pesticide drift and exposure (including glyphosate and imidacloprid) is a problem that applies to both terrestrial and marine environments. To avoid the introduction of toxic pesticides into ecosystems at the place of origin, advocates are calling on strengthening organic standards and providing new incentives to expand the domestic production and consumption of organic foods and products. See Keeping Organic Strong to learn how to engage with the National Organic Standards Board Spring 2024 meeting. Whether or not you live in a coastal city or along a waterway, see Parks for a Sustainable Future to learn about how to transition a higher education institution or a local parks department to organic land management principles.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Marine Pollution Bulletin
